CN103419656B - The power system of electronlmobil, electronlmobil and heating of battery method - Google Patents

Abstract

The invention provides a kind of power system of electronlmobil, comprise battery pack, cell heater, battery manager, switch box, motor, electric machine controller and isolation inductance.Cell heater is connected with battery pack; Battery manager is connected with cell heater with battery pack respectively, for the temperature in battery pack lower than the first heating-up temperature threshold value and dump energy higher than parking power threshold after control cell heater be battery pack heating, and permission electronlmobil driving heating the time limit power travel; The voltage that switch box is used for battery pack exports distributes; Electric machine controller is connected with switch box with motor, the pre-charging capacitor having first, second input end and be connected between the first and second input ends; Isolation inductance needs to mate with described pre-charging capacitor.This power system can realize heating, and the efficiency of heating surface is high, cost is low, practical.The present invention also proposes a kind of heating of battery method of electronlmobil and a kind of electronlmobil.

Description

Electric vehicle, electric vehicle power system and battery heating method

technical field

The invention relates to the technical field of electric vehicles, in particular to a battery heating method of an electric vehicle, a power system of the electric vehicle using the method, and an electric vehicle with the power system.

Background technique

With the continuous development of science and technology, new energy vehicles, especially pure electric vehicles, are slowly entering every family as a means of transportation. Users have higher and higher requirements for vehicle performance, especially for comfort. Vehicles are required to adapt to different driving needs. However, most pure electric vehicles at this stage obviously cannot meet this requirement, especially in the cold winter, when the temperature is too low, the performance of the power battery will decline, both in terms of discharge capacity and battery capacity. Can't even use it. Specifically, the general operating temperature of power batteries, especially lithium-ion batteries, is -20°C to 55°C, and batteries are not allowed to be charged at low temperatures. When the ambient temperature is too low, the internal battery of the electric vehicle will have the following problems: (1) At low temperature, lithium ions are easy to deposit on the negative electrode, lose electrical activity, and may even cause safety problems. Therefore, vehicles and battery packs are often used at low temperatures, which will greatly damage the life of the battery pack, and may cause safety hazards in more serious cases. (2) At low temperature, when lithium-ion batteries are charged, lithium ions are easily deposited on the negative electrode and become dead lithium, and the capacity that the battery can exert is significantly reduced. Cause an internal short circuit, causing a safety hazard. This is why vehicles cannot be charged (including regenerative) at low temperatures. (3) At low temperature, the discharge capacity of the battery is limited, which is not conducive to driving. These problems are undoubtedly very embarrassing for pure electric vehicles that advertise new energy and green environmental protection. Therefore, there is an increasing call for a power battery heating solution that can change this dilemma.

The battery heating solution is a very important technology in the field of pure electric vehicles. The quality of the battery heating strategy and the performance of the battery heater directly affect the comfort, operation stability and safety of the car. At present, many new technologies have begun to be applied to battery heating, but due to their own performance defects, they have not been widely used in the automotive field. For example, add an insulation cover to the outside of the battery, and use insulation materials to insulate and keep warm. cover, to play a role in heat preservation; or add a heating patch on the outer surface of the battery, etc. Most of these schemes utilize external huge heating equipment and power supply to heat the battery, so these schemes are only suitable for the example where the battery position is fixed. In addition, using an external power source to heat the battery of a pure electric vehicle has limitations and is not suitable for vehicles that are not in a fixed location. Therefore, these heating technologies have not been widely used in pure electric vehicles.

Contents of the invention

The purpose of the present invention is to solve at least one of the above-mentioned technical drawbacks.

For this reason, the first object of the present invention is to propose a power system for an electric vehicle. The system does not need an external power supply, and the power required for heating is completely provided by its own power battery, which greatly reduces the limitation of the use of the electric vehicle in a low temperature environment. The efficiency is also high, the cost is low, and the practicability is strong. The second object of the present invention is to provide an electric vehicle with the above-mentioned power system. Another object of the present invention is to provide a battery heating method for an electric vehicle.

To achieve the above object, the embodiment of the first aspect of the present invention discloses a power system of an electric vehicle, comprising: a battery pack; a battery heater, the battery heater is connected to the battery pack, and the battery heater It is configured to charge and discharge the battery pack to heat the battery pack, wherein the battery heater has an output power adjustment module, and the output power adjustment module is used to adjust the charging current and /or adjust the discharge current to adjust the heating power of the battery pack; the battery manager, the battery manager is connected to the battery pack and the battery heater respectively, for when the temperature of the battery pack is lower than After the first heating temperature threshold and the remaining power of the battery pack is higher than the parking power threshold, adjust the battery heater to heat the battery pack in different heating start modes according to the temperature of the battery pack and the remaining power, And the output power adjustment module controls the battery heater to heat the battery pack with the corresponding heating power according to the temperature of the battery pack, and controls the battery heater to heat the battery pack at intervals; An electric box, the distribution box is used to distribute the voltage output by the battery pack; a motor; a motor controller, the motor controller is connected to the motor and the distribution box respectively, and the motor controls The device has a first input terminal, a second input terminal, and a pre-charged capacitor connected between the first input terminal and the second input terminal, and the motor controller is used to distribute according to the control command and the distribution box voltage to supply power to the motor; and an isolation inductor connected between the battery pack and the distribution box, and the inductance value of the isolation inductor is the same as the pre-charge capacity of the motor controller match.

According to the power system of the electric vehicle in the embodiment of the present invention, the power battery in the battery pack on the vehicle is discharged with a large current, and the internal resistance of the battery itself generates heat to achieve the purpose of heating the battery pack. The power system does not require an external power supply, and the power required for heating is completely provided by the power battery of its own battery pack. The battery pack is heated and managed through the battery manager and battery heater, which greatly reduces the restrictions on the use of electric vehicles in low-temperature environments and can meet Customer driving and charging requirements at low temperature. In addition, the power system directly heats the power battery, which has higher heating efficiency, lower cost and strong practicability.

The embodiment of the second aspect of the present invention discloses an electric vehicle, including the above-mentioned power system of the electric vehicle. The vehicle can drive normally in cold areas, and can heat the battery pack while driving, so as to ensure safe and smooth driving.

The embodiment of the third aspect of the present invention discloses a battery heating method for an electric vehicle, comprising the following steps: detecting the temperature of the battery pack and the remaining power of the battery pack; if the temperature of the battery pack is lower than the first heating temperature threshold and the remaining power of the battery pack is higher than the parking power threshold, the battery manager adjusts the battery heater according to the temperature of the battery pack and the remaining power to start heating the battery The battery pack is heated, and the battery heater is controlled by the output power adjustment module according to the temperature of the battery pack to heat the battery pack with the corresponding heating power, and the battery heater is controlled to heat the battery pack at intervals Heating; if the temperature of the battery pack is lower than the first heating temperature threshold and the remaining power of the battery pack is lower than the parking power threshold, the battery manager issues a command to prohibit the electric vehicle from heating, driving or charging; and if the temperature of the battery pack is higher than the first heating temperature threshold, the battery manager controls the main contactor in the distribution box to close.

According to the battery heating method of the electric vehicle in the embodiment of the present invention, the pure electric vehicle can realize the heating of the power battery of the battery pack without relying on an external power source, so that the temperature of the battery pack can rise to the required temperature, and then follow the normal discharge and charge strategy The use of battery packs greatly reduces the restrictions on the use of electric vehicles in low-temperature environments, and can meet the requirements of customers for driving and charging at low temperatures. At the same time, the battery heating method of the embodiment of the present invention adopts different heating starting methods, and uses different power heating according to the real-time temperature of the battery pack, and the control is more precise, so that the performance of the battery pack can be fully utilized and the safety is improved. In addition, the method of the embodiment of the present invention judges whether the output power of the battery pack is too large by sampling the rate of change of the throttle depth of the electric vehicle, thereby stopping heating the battery pack when the output power of the battery pack is too large, thereby avoiding the battery pack The over-discharge of the electricity improves the service life of the battery pack and ensures the power of the electric vehicle. Heating is carried out at intervals in time, that is, the heating is stopped for a period of time, so that the battery pack is heated periodically, which alleviates the impact of high current on the battery pack and improves the service life of the battery pack.

Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Description of drawings

The above and/or additional aspects and advantages of the present invention will become apparent and easy to understand from the following description of the embodiments in conjunction with the accompanying drawings, wherein:

FIG. 1 is a schematic structural diagram of a power system of an electric vehicle according to an embodiment of the present invention;

2 is a schematic structural diagram of a power system of an electric vehicle according to another embodiment of the present invention;

3A is an electrical schematic diagram of a power system of an electric vehicle according to an embodiment of the present invention;

3B is an electrical schematic diagram of a power system of an electric vehicle according to another embodiment of the present invention

FIG. 4 is a schematic diagram of electrical connection of a power system of an electric vehicle according to another embodiment of the present invention;

FIG. 5 is a schematic diagram of electrical connection of a power system of an electric vehicle according to an embodiment of the present invention;

6 is a schematic structural diagram of a distribution box in a power system of an electric vehicle according to an embodiment of the present invention;

7 is a flowchart of a battery heating method for an electric vehicle according to an embodiment of the present invention;

8 is a flowchart of a battery heating method for an electric vehicle according to another embodiment of the present invention;

FIG. 9 is a further flow chart of a battery heating method for an electric vehicle according to an embodiment of the present invention;

10 is a further flowchart of a battery heating method for an electric vehicle according to another embodiment of the present invention; and

FIG. 11 is a general flowchart of a battery heating method for an electric vehicle according to an embodiment of the present invention.

detailed description

Embodiments of the present invention are described in detail below, examples of which are shown in the drawings, wherein the same or similar reference numerals designate the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the figures are exemplary only for explaining the present invention and should not be construed as limiting the present invention.

In describing the present invention, it should be understood that the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", The orientation or positional relationship indicated by "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than Nothing indicating or implying that a referenced device or element must have a particular orientation, be constructed, and operate in a particular orientation should therefore not be construed as limiting the invention.

In the description of the present invention, it should be noted that unless otherwise specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a mechanical connection or an electrical connection, or it can be two The internal communication of each element may be directly connected or indirectly connected through an intermediary. Those skilled in the art can understand the specific meanings of the above terms according to specific situations.

These and other aspects of embodiments of the invention will become apparent with reference to the following description and drawings. In these descriptions and drawings, some specific implementations of the embodiments of the present invention are specifically disclosed to represent some ways of implementing the principles of the embodiments of the present invention, but it should be understood that the scope of the embodiments of the present invention is not limited by this limit. On the contrary, the embodiments of the present invention include all changes, modifications and equivalents coming within the spirit and scope of the appended claims.

A power system of an electric vehicle according to an embodiment of the first aspect of the present invention will be described below with reference to FIGS. 1 to 10 .

1 and 2, the power system of the electric vehicle includes: a battery pack 101, a battery heater 102, a battery manager 103, a distribution box 104, a motor 105, a motor controller 106 and an isolation inductor L2. in:

3A or 3B, the battery heater 102 is connected to the battery pack 101, the battery heater 102 is configured to charge and discharge the battery pack 101 to heat the battery pack, the battery heater 102 has an output power adjustment module 1021, the output The power adjustment module 1021 is used for adjusting the charging current and/or discharging current of the battery pack 101 to adjust the heating power of the battery pack 101 . The battery manager 103 is connected to the battery heater 102 through the CAN line 107 , and is also connected to the battery pack 101 through the sampling line 108 . In addition, the battery manager 103 also has the functions of judging the current vehicle state of the electric vehicle, calculating the temperature and remaining power of the battery pack 101, and can send control signals to related electrical devices through the CAN line 107, so as to realize the control of each related device. Function management. Specifically, the battery manager 103 is used to adjust the battery heater according to the temperature and remaining power of the battery pack 101 after the temperature of the battery pack 101 is lower than the first heating temperature threshold and the remaining power of the battery pack 101 is higher than the parking power threshold 102 heats the battery pack in different heating start modes, and controls the battery heater 102 to heat the battery pack 101 with the corresponding heating power through the output power adjustment module 1021 according to the temperature of the battery pack, and controls the battery heater 102 at intervals to The battery pack 101 is heated. The distribution box 104 is a high-voltage device that switches a large current. The battery manager 103 distributes the voltage output by the battery pack 101 by sending a control signal to the distribution box 104 . The motor controller 106 is connected to the motor 105 and the distribution box 104 respectively, and the motor controller 106 has a first input terminal, a second input terminal and a pre-charged capacitor C2 connected between the first input terminal and the second input terminal, The motor controller 106 is used to supply power to the motor 105 according to the control instruction and the voltage distributed to the motor controller by the distribution box 104 . Specifically, the motor controller 106 inverts the DC power provided by the battery pack 101 into the three-phase AC power required by the motor 105 through its internal drive circuit to supply power to the motor 105, and can , to realize the control of the motor. The inductance value of the isolation inductor L2 matches the precharge capacitor C2 of the motor controller.

In one embodiment of the present invention, the battery heater performs a fault self-test and sends the test result to the battery manager.

Specifically, as shown in FIG. 3A and/or FIG. 3B , the battery heater includes: a first switch module 301 , a first capacitor C1 , a first inductor L1 and a second switch module 302 . Wherein, one end of the first switch module 301 is respectively connected to the first electrode of the battery pack 101 and the isolation inductor L2; one end of the first capacitor C1 is connected to the other end of the first switch module 301, and the other end of the first capacitor C1 is connected to the The second electrode of the battery pack 101 is connected; one end of the first inductor L1 is connected to the node between the first switch module 301 and the first capacitor C1; one end of the second switch module 302 is connected to the other end of the first inductor L1, and The other end of the second switch module 302 is connected to the second electrode of the battery pack 101 . Both the control ends of the first switch module 301 and the second switch module 302 are connected to the battery manager 103. When the battery pack 101 is heated, the battery manager 103 sends a signal to the battery heater 102, and the battery heater 102 controls the first switch. The module 301 and the second switch module 302 are sequentially turned on to generate charging current and discharge current in the above-mentioned battery pack sequentially, and when the first switch module 301 is turned on, the second switch module 302 is turned off, and when the second switch module 302 is turned on At this time, the first switch module 301 is turned off. It should be noted that, in this embodiment, the number of the first capacitor C1 may be one or multiple, as shown in FIG. 3A and/or FIG. 3B, the number of the first capacitor C1 is four , in order to simplify the description and distinguish multiple first capacitors C1, as shown in Figure 3A or Figure 3B, the four first capacitors C1 are respectively represented as C11, C12, C13 and C14 and C.1, C.2, C.3 and C.4.

Further, as shown in FIG. 3A or FIG. 3B , ESR in the battery pack 101 is the equivalent internal resistance of the battery pack, ESL is the equivalent inductance of the battery pack, and E is the battery pack. L2 is an isolation inductor, which is used to isolate the battery heating circuit Part2 from the motor equivalent load circuit Part5, so that the reverse voltage of the battery pack 101 is absorbed by the isolation inductor L2 and will not be added to the subsequent load. C2 is the precharge capacity, and R is the equivalent load of the motor. When the battery heater is working, its internal switch module is turned on and off according to a certain sequence.

In an example of the present invention, as shown in FIG. 3A or FIG. 3B , the switch module may be an IGBT (Insulated Gate Bipolar Transistor, insulated gate bipolar transistor). When the heating starts, the internal components such as inductors and capacitors are in the initial state and do not store energy. The working process of the battery heater includes: (1) When IGBT1 is turned on and IGBT2 is turned off, the battery pack E passes through the circuit "C1-D1 -ESL-ESR-E-C1” charges the first capacitor C1. After charging for a period of time, the voltage across the first capacitor C1 is equal to the voltage of the battery pack E, but due to the presence of inductive elements in the circuit, the second The first capacitor C1 continues to charge, and the voltage across the first capacitor C1 is higher than the voltage of the battery pack E. When the charging current is zero, the first capacitor C1 starts to discharge. At this time, the discharge circuit is "C1-D1-ESL-ESR-E- C1" until the discharge current is zero. (2) IGBT1 is turned off, and when IGBT2 is turned on, the first capacitor C1 continues to discharge. There is a discharge circuit as "C1-D2-L1-IGBT2-C1". Due to the existence of the first inductor L1, the first capacitor C1 continues to discharge, so that the voltage across the first capacitor C1 is lower than the voltage of the battery pack E. Repeat the above process like this.

As shown in Figure 3A, due to the selection of different first capacitors C1 (C11, C12, C13 or C14), the peak voltages of C11, C12, C13 or C14 in the discharge circuit 2 (heating circuit) will be different, and the heating circuit The peak values of the forward current and reverse current in are different, so the heating power is different, that is, the larger the capacitance, the greater the heating power. And changing the duty ratio (pulse width) of the output pulse of the second switch module 302 will affect the forward charging and reverse charging action time of the battery heating circuit, and the general circuit will have a corresponding optimal point.

Therefore, as a specific example, the output power adjustment module 1021 is configured to adjust the duty cycle of the output pulses of the first switch module 301 and the second switch module 302 according to the instruction of the battery manager 103 . The battery manager 103 sends a CAN signal (command) to the output power adjustment module 1021 of the battery heater 102 according to the temperature of the battery pack 101 (battery pack), so that the output power adjustment module 1021 is connected to the corresponding first capacitor C1 (C11, C12, C13 or C14), in order to achieve the purpose of changing the second switch module 302 (IGBT2) pulse width (duty cycle of the output pulse), so that the heating power of the battery electric heater 102 changes accordingly, so as to better adapt to the battery pack 101. Discharge law. Specifically, if different first capacitors C1 are selected, such as C11, C12, C13 or C14, the peak voltage of the first capacitor C1 in the discharge circuit 2 (heating circuit) will be different, and the discharge circuit 2 (heating circuit) The peak value of the forward current and the reverse current are different, therefore, the power to heat the battery pack 101 is different, the selection of different C11, C12, C13 or C14 for the first capacitor C1 will change the output pulse of the second switch module 302 (IGBT2) The duty ratio (pulse width) of the pulse width changes accordingly with the change of the first capacitor C1, but generally the change cannot be too large and can only be fine-tuned, as shown in Figure 3A, the size of C11, C12, C13, and C14 The relationship is, for example, C11<C12<C13<C14. Therefore, by selecting capacitors with different capacitances to be used as the first capacitor C1, the heating power will be changed.

Generally speaking, the lower the temperature of the battery pack 101 is, the lower the discharge capacity of the battery pack 101 is, the voltage is relatively lower, and the output power is also lower. Therefore, selecting different heating powers according to the temperature of different battery packs 101 is in line with the battery discharge characteristics. As shown in Figure 3A, when the temperature is very low, you can choose to turn on C11 and choose a smaller heating power.

As shown in Figure 3B, in another example of the present invention, multiple first capacitors C1 (C.1, C.2, C.3 and C.4) can also be the same, by changing the connection of the first capacitor C1 The quantity changes the heating power. That is, when there are multiple first capacitors C1 , the output power adjustment module 1021 adjusts the number of connected first capacitors C1 according to the instruction of the battery manager 103 .

Specifically, in combination with Figure 3B, C.1, C.2, C.3 and C.4 are arranged in parallel, and according to the electrical characteristics of the capacitors, if two capacitors are connected in parallel, the total equivalent capacitance is the sum of the two. Therefore, assume that the capacitance values of the four capacitors C.1, C.2, C.3 and C.4 are all equal. And in conjunction with the foregoing embodiments, the following definitions can be made:

C11=C.1; C12=C.1+C.2; C13=C.1+C.2+C.3; C14=C.1+C.2+C.3+C.4.

Therefore, C14=4*C.1, C13=3*C.1, C12=2*C.1, C11=C.1.

By adjusting the number of connected capacitors, the purpose of changing the size of the capacitor and thus the heating power can also be achieved. According to the above embodiments, the output power adjustment module 1021 is a relay, as shown in FIG. 3A and/or FIG. 3B .

According to the power system of the electric vehicle in the embodiment of the present invention, when the first switch module 301 is turned on, if the isolation inductance L2 is not added, the precharge capacitor C2 charges the first capacitor C1 through the first switch module 301, and the charging current The size is determined by the impedance in the loop, which makes the current waveform of the first capacitor C1 uncontrollable, and the characteristics of the heating circuit are changed, thus causing the circuit to not work normally. Therefore, when the motor 105 and the battery heater 102 work simultaneously, an isolation inductance L2 needs to be added.

In one embodiment of the present invention, the inductance L of the isolation inductor L2 is determined according to the following formula: Among them, T is the equivalent load duty cycle of the motor, and C is the capacitance value of the precharge capacitor C2.

In one embodiment of the present invention, the battery heater 102 further includes a power connector for connecting and fixing the power line 109 . The power connector needs to meet the anti-eddy current requirements, and because the current change frequency is very fast during the battery heater 102 operation, the magnetic permeability material inside the power connector rises rapidly, so the magnetic permeability of the power connector should be low. In addition, the battery heater 102 also includes a low-voltage connector for connecting and communicating with external systems, including a CAN line 107 for connecting to the battery manager 103 and a self-test signal line and a fault signal line.

Referring to FIGS. 2 and 4 , in one embodiment of the present invention, the isolation inductor L2 is placed inside the battery heater 102 . As shown in FIG. 4 , the inside of the battery heater 102 includes an isolation inductor L2 , a fuse 401 and the heater's own electrical components. In addition, the battery heater 102 also includes four power connectors, two of which are connected to the battery pack 101 through power lines 109 , and the other two power connectors are connected to the distribution box 104 through power lines 109 , as shown in FIG. 2 . In one embodiment of the present invention, power connectors are used at the beginning and end of the high voltage wire harness.

According to the power system of the electric vehicle of the embodiment of the present invention, the isolation inductor L2 is installed inside the battery heater 102, and its advantage is that when the battery heating is not needed, the battery heater 102 can be completely removed, and the distribution box 104 and the The battery pack 101 is connected. Electric vehicles do not need external battery heaters in places with high temperatures, and battery heaters are installed in cold places, so there is no need to make too many changes to adapt to sales regions during model development, which greatly helps to save costs.

Referring to FIG. 1 and FIG. 5 , in another embodiment of the present invention, the isolation inductor L2 can also be placed inside the distribution box 104 . It can be understood that whether the isolation inductor L2 is placed in the battery heater or the distribution box, it is between the battery pack and the distribution box. As shown in Figure 1, there is no power line connection between the distribution box 104 and the battery heater 102. Specifically, the battery pack 101 includes four power connectors, which are connected to the distribution box 104 through two power lines 109, and then It is connected to the battery heater 102 through the other two power lines 109 . However, it is necessary to add a relay 501 as an on-off device for the isolation inductor L2 to select whether to connect the isolation inductor L2 to the circuit, as shown in FIG. 5 . The battery heater 102 and the distribution box 104 are connected in parallel. In addition, a fuse 401 is installed inside the battery pack 101 .

According to the power system of the electric vehicle of the embodiment of the present invention, the isolation inductor L2 is installed inside the distribution box 104, which has the advantage that the influence of the battery heater 102 on the distribution box 104 is greatly reduced. In addition, when the battery is heating, the relay 501 connects the isolation inductance L2 into the circuit; when the battery is not heating, the relay 501 removes the isolation inductance L2 out of the circuit.

In one embodiment of the present invention, referring to FIG. 1 , FIG. 2 and FIG. 3A and FIG. 3B , the battery heater 102 in the power system of an electric vehicle further includes a cooling assembly 110 for cooling the first battery heater 102 The switch module 301 and the second switch module 302 are cooled.

In one embodiment of the present invention, the cooling assembly 110 further includes an air duct disposed in the battery heater and a fan disposed at one end of the air duct. The battery heater uses a fan for cooling.

In another embodiment of the present invention, the cooling assembly 110 further includes a cooling liquid channel disposed in the battery heater, and a cooling liquid inlet and a cooling liquid outlet disposed on the battery heater.

The battery heater adopts cooling liquid for heat dissipation, which has good heat dissipation effect and excellent sealing performance.

In one embodiment of the present invention, as shown in FIG. 6 , the distribution box 104 in the power system of the electric vehicle further includes: a main contactor 601 and a pre-charging contactor 602 . Wherein, the main contactor 601 is used for distributing the output voltage of the distribution box 104 to the electrical equipment of the electric vehicle, such as the motor 105 , under the control of the battery manager 103 . The pre-charging contactor 602 is connected to one of the first input terminal 603 and the second input terminal 604 of the motor controller 106. In this embodiment, as shown in FIG. 6, the pre-charging contactor 602 is connected to the first input terminal 603 connected. It can be understood that the pre-charging contactor 602 can also be connected to the second input terminal 604 in other embodiments. The pre-charging contactor 602 is used to charge the pre-charging capacitor C2 under the control of the battery manager 103 before the motor controller 106 controls the motor 105 to start.

In one embodiment of the present invention, when the remaining power of the battery pack (also referred to as SOC, StateOfCharge) is higher than the driving power threshold, the electric vehicle is allowed to enter the driving heating mode, wherein the driving power threshold is higher than the above-mentioned Parking power threshold.

Driving heating specifically means that in addition to the battery heater heating the battery pack, other high-voltage electrical equipment of electric vehicles can also work at the same time, such as motors, air conditioners, etc., but the motors and air conditioners will be limited to power operation. Correspondingly, parking heating means that in addition to the battery heater heating the battery pack, other high-voltage electrical equipment of the electric vehicle does not work. For example, when the heater is working, the high-voltage electrical equipment such as the motor and air conditioner does not work. Correspondingly, the driving power threshold refers to the remaining power of the battery pack when the electric vehicle is allowed to enter the driving heating mode, and the parking power refers to the remaining power of the battery pack when the electric vehicle is allowed to enter the parking heating mode.

Specifically, as shown in Figure 7, when any of the following conditions is met, the battery manager controls the battery heater to heat the battery pack during driving:

When the temperature of the battery pack is higher than the first temperature threshold and lower than the second temperature threshold, and the remaining power of the battery pack is higher than the first power threshold;

When the temperature of the battery pack is higher than the second temperature threshold and lower than the third temperature threshold, and the remaining power of the battery pack is higher than the second power threshold, wherein the second power threshold is lower than the first power threshold;

When the temperature of the battery pack is higher than the third temperature threshold and lower than the fourth temperature threshold, and the remaining power of the battery pack is higher than the third power threshold, wherein the third power threshold is lower than the second power threshold;

When the temperature of the battery pack is higher than the fourth temperature threshold and lower than the fifth temperature threshold, and the remaining power of the battery pack is higher than the fourth power threshold, wherein the fourth power threshold is lower than the third power threshold.

In an example of the present invention, as shown in FIG. 7, the first temperature threshold, the second temperature threshold, the third temperature threshold, the fourth temperature threshold, and the fifth temperature threshold may be -30°C, -25°C, - At 20°C, -15°C, and -10°C, the first power threshold, the second power threshold, the third power threshold, and the fourth power threshold can be 30%, 27.5%, 25%, and 22.5% of the total power of the battery pack, respectively.

In another embodiment of the present invention, as shown in FIG. 8, specifically, the battery manager judges whether the temperature of the battery pack is higher than the ninth temperature threshold, and if so, the remaining power of the battery pack is higher than the eighth power threshold , the battery manager controls the battery heater to heat the battery pack during driving; if not, the battery manager judges whether the temperature of the battery pack is higher than the eighth temperature threshold, if yes, and the remaining power of the battery pack is higher than the seventh power threshold, Then the battery manager controls the battery heater to heat the battery pack during driving; if not, the battery manager judges whether the temperature of the battery pack is higher than the seventh temperature threshold, if yes, and the remaining power of the battery pack is higher than the sixth power threshold, then The battery manager controls the battery heater to heat the battery pack during driving; if not, the battery manager judges whether the temperature of the battery pack is higher than the sixth temperature threshold; if yes, and the remaining power of the battery pack is higher than the fifth power threshold, the battery The manager controls the battery heater to heat the battery pack while driving. Wherein, the seventh temperature threshold is higher than the sixth temperature threshold, the eighth temperature threshold is higher than the seventh temperature threshold, the ninth temperature threshold is higher than the eighth temperature threshold; the sixth power threshold is lower than the fifth power threshold, and the seventh power threshold The eighth power threshold is lower than the sixth power threshold, and the eighth power threshold is lower than the seventh power threshold.

In an example of the present invention, as shown in FIG. 8, the sixth temperature threshold, the seventh temperature threshold, the eighth temperature threshold, and the ninth temperature threshold may be -30°C, -25°C, -20°C, -15°C, respectively. °C, the fifth power threshold, the sixth power threshold, the seventh power threshold, and the eighth power threshold may be 30%, 27.5%, 25%, and 22.5% of the total power of the battery pack, respectively.

In one embodiment of the present invention, when the remaining power of the battery pack is lower than the above-mentioned driving power threshold and higher than the above-mentioned parking power threshold, the electric vehicle is allowed to enter the parking heating mode.

Specifically, as shown in Figure 7, when any of the following conditions is met, the battery manager controls the battery heater to heat the battery pack when it is parked:

When the temperature of the battery pack is higher than the tenth temperature threshold and lower than the eleventh temperature threshold, and the remaining power of the battery pack is higher than the ninth power threshold;

When the temperature of the battery pack is higher than the eleventh temperature threshold and lower than the twelfth temperature threshold, and the remaining power of the battery pack is higher than the tenth power threshold, wherein the tenth power threshold is lower than the ninth power threshold;

When the temperature of the battery pack is higher than the twelfth temperature threshold and lower than the thirteenth temperature threshold, and the remaining power of the battery pack is higher than the eleventh power threshold, wherein the eleventh power threshold is lower than the tenth power threshold;

When the temperature of the battery pack is higher than the thirteenth temperature threshold and lower than the fourteenth temperature threshold, and the remaining power of the battery pack is higher than the twelfth power threshold, wherein the twelfth power threshold is lower than the eleventh power threshold .

In an example of the present invention, as shown in FIG. 7, the tenth temperature threshold, the eleventh temperature threshold, the twelfth temperature threshold, the thirteenth temperature threshold, and the fourteenth temperature threshold may be -30°C, -30°C, - 25°C, -20°C, -15°C, -10°C, the ninth power threshold, the tenth power threshold, the eleventh power threshold, and the twelfth power threshold can be 20%, 17.5%, and 15%, 12.5%.

In another embodiment of the present invention, as shown in FIG. 8, specifically, the battery manager judges whether the temperature of the battery pack is higher than the eighteenth temperature threshold, and if so, the remaining power of the battery pack is higher than the sixteenth temperature threshold. power threshold, the battery manager controls the battery heater to stop and heat the battery pack; if not, the battery manager judges whether the temperature of the battery pack is higher than the seventeenth temperature threshold, and if so, the remaining power of the battery pack is higher than the tenth threshold The battery manager controls the battery heater to stop and heat the battery pack; if not, the battery manager judges whether the temperature of the battery pack is higher than the sixteenth temperature threshold, and if so, the remaining power of the battery pack is higher than the sixteenth temperature threshold. 14 power threshold, the battery manager controls the battery heater to heat the battery pack; if not, the battery manager judges whether the temperature of the battery pack is higher than the fifteenth temperature threshold, and if so, the remaining power of the battery pack is higher than At the thirteenth power threshold, the battery manager controls the battery heater to heat the battery pack when it is parked. Among them, the sixteenth temperature threshold is higher than the fifteenth temperature threshold, the seventeenth temperature threshold is higher than the sixteenth temperature threshold, the eighteenth temperature threshold is higher than the seventeenth temperature threshold; the fourteenth power threshold is lower than the tenth Three power thresholds, the fifteenth power threshold is lower than the fourteenth power threshold, and the sixteenth power threshold is lower than the fifteenth power threshold.

In an example of the present invention, as shown in FIG. 8, the fifteenth temperature threshold, the sixteenth temperature threshold, the seventeenth temperature threshold, and the eighteenth temperature threshold may be -30°C, -25°C, -20°C, respectively. °C, -15°C, the thirteenth power threshold, the fourteenth power threshold, the fifteenth power threshold, and the sixteenth power threshold can be 20%, 17.5%, 15%, and 12.5% of the total power of the battery pack, respectively.

According to the power system of the electric vehicle in the embodiment of the present invention, the battery manager can control the battery heater to heat the battery pack in the driving heating mode or the parking heating mode through the real-time temperature and remaining power of the battery pack, and the control accuracy is finer and easier to implement .

In one embodiment of the present invention, as shown in Figure 9, the battery manager is also used to control the battery heater to heat the battery pack, if the driver presses the heating button again for a preset time, then It is judged whether the operation of pressing the heating button again satisfies the preset condition, and if it is judged to be satisfied, the electric vehicle and/or the battery heater are further controlled according to the temperature of the battery pack and the remaining power. Specifically, if the temperature of the battery pack is lower than the nineteenth temperature threshold, the battery manager issues a prompt to prohibit heating, driving or charging of the electric vehicle; if the temperature of the battery pack is higher than the nineteenth temperature threshold, the battery manager Control the battery heater to stop heating the battery pack. Further, if the temperature of the battery pack is higher than the nineteenth temperature threshold, and the remaining power of the battery pack is lower than the seventeenth power threshold, the battery manager will issue a prompt to prohibit heating, driving or charging of the electric vehicle; and if the battery If the remaining power of the battery pack is higher than the seventeenth power threshold, and the temperature of the battery pack is higher than the nineteenth temperature threshold, the battery manager allows the electric vehicle to run with limited power.

In an example of the present invention, as shown in FIG. 9 , the nineteenth temperature threshold may be -20° C., and the seventeenth power threshold may be 25% of the total power of the battery pack.

In yet another embodiment of the present invention, the battery manager is used to adjust the output power of the battery heater according to the real-time temperature of the battery pack, so as to enter different heating processes to heat the battery pack. Specifically, as shown in Figure 10, when the temperature of the battery pack is higher than the third heating temperature threshold and lower than the fourth heating temperature threshold, the battery manager controls the battery heater to heat the battery pack with the first power; When the temperature of the battery pack is higher than the fourth heating temperature threshold and lower than the fifth heating temperature threshold, the battery manager controls the battery heater to heat the battery pack with the second power; when the temperature of the battery pack is higher than the fifth heating temperature threshold and lower than When the sixth heating temperature threshold is reached, the battery manager controls the battery heater to heat the battery pack with the third power; when the temperature of the battery pack is higher than the sixth heating temperature threshold and lower than the seventh heating temperature threshold, the battery manager controls the battery The heater heats the battery pack with the fourth power. In an example of the present invention, the third heating temperature threshold, the fourth heating temperature threshold, the fifth heating temperature threshold, the sixth heating temperature threshold, and the seventh heating temperature threshold may be -30°C, -25°C, -20°C, respectively. °C, -15 °C, -10 °C.

In one embodiment of the present invention, as shown in Figure 10, the battery manager is also used to judge whether the heating time reaches the first preset time (T1), and when it is judged to reach the first preset time, control the battery heater Stop heating the battery pack. At the same time, the battery manager is also used to calculate the stop time after controlling the battery heater to stop heating the battery pack, and restart the battery heater to heat the battery pack when the stop time reaches the second preset time (T2).

In another preferred embodiment of the present invention, the battery manager 103 controls the battery heater to stop by judging whether the current throttle depth change rate of the electric vehicle has reached a preset threshold, and when judging that the preset threshold is reached, the battery heater is controlled to stop The battery pack is heated to determine whether to heat the battery pack 101, that is, if it is judged that the current throttle depth change rate of the electric vehicle reaches a preset threshold, the battery manager 103 controls the battery heater 102 to stop heating the battery pack 101 ; If not, the battery manager 103 controls the battery heater 102 to continue heating the battery pack 101 . It can be understood that the throttle depth change rate is determined according to the throttle depth change value of the electric vehicle within a certain period of time. heating. Specifically, for example, when the electric vehicle accelerates suddenly or travels on an uphill section, more power support is required, so the current throttle change rate of the electric vehicle will become larger (the output power increases), and the battery pack 101 has an instantaneous electric output power. Threshold value (preset threshold), the preset threshold is the current throttle change rate of the electric vehicle when the battery pack 101 can provide the maximum power support for the electric vehicle, therefore, once the current throttle change rate of the electric vehicle reaches the preset threshold , under normal circumstances, the instantaneous output power of the battery pack 101 is already the maximum. At this time, it will not be able to provide output power for the battery heater 102. Therefore, the safety of the battery pack 101 can be guaranteed, the overload discharge of the battery pack can be avoided, and the battery pack can be further improved. Service life of group 101.

According to the power system of the electric vehicle in the embodiment of the present invention, the battery pack on the vehicle is discharged with a large current, and the internal resistance of the power battery itself generates heat to achieve the purpose of heating the battery pack. The power system does not need an external power supply, and the power required for heating is completely provided by its own battery pack. The battery pack is heated and managed through the battery manager and battery heater, which greatly reduces the restrictions on the use of electric vehicles in low-temperature environments, and can realize electric vehicles. Heating while driving can meet the limited power operation of electric vehicles while heating the battery, and meet customers' driving and charging requirements at low temperatures. In addition, the power system directly heats the battery, which has higher heating efficiency, lower cost, strong practicability, and easy industrialization.

The embodiment of the second aspect of the present invention discloses an electric vehicle, including the above-mentioned power system of the electric vehicle. The vehicle can drive normally in cold areas, and can heat the battery pack while driving, so as to ensure safe and smooth driving.

A battery heating method for an electric vehicle according to an embodiment of the third aspect of the present invention will be described below with reference to FIGS. 7 to 11 .

As shown in Figure 11, the battery heating method for electric vehicles includes the following steps:

Step S1101: Detect the temperature of the battery pack and the remaining power of the battery pack;

Step S1102: If the temperature of the battery pack is lower than the first heating temperature threshold and the remaining power of the battery pack is higher than the parking power threshold, the battery manager adjusts the battery heater according to the temperature of the battery pack and the remaining power to start the heating in different ways Heat the battery pack, and control the battery heater to heat the battery pack with the corresponding heating power according to the temperature of the battery pack through the output power adjustment module, and control the battery heater to heat the battery pack at intervals;

Step S1103: If the temperature of the battery pack is lower than the first heating temperature threshold and the remaining power of the battery pack is lower than the parking power threshold, the battery manager issues a prompt to prohibit heating, driving or charging of the electric vehicle;

Step S1104: If the temperature of the battery pack is higher than the first heating temperature threshold, the battery manager controls the main contactor in the distribution box to close.

Specifically, in one embodiment of the present invention, as shown in FIG. 7, the battery heating method of an electric vehicle includes the following steps:

Step S701: Turn ON the electricity on the whole vehicle.

Step S702: Detect whether the temperature of the battery pack is lower than the first heating temperature threshold. The battery manager detects the temperature of the battery pack in the vehicle. If the temperature of the battery pack is higher than the first heating temperature threshold, the battery pack does not need to be heated, and step S703 is performed; if it is lower than the first heating temperature threshold, the battery pack needs to be detected. , execute step S704.

Step S703: the battery manager controls the main contactor in the distribution box to close. Before the main contactor is closed, the battery manager controls the pre-charging contactor to be closed, and after the pre-charging is completed, the main contactor is closed.

Step S704: The battery manager judges whether the heating and driving conditions are met according to the temperature of the battery pack and the remaining power. Specifically, if the remaining power of the battery pack is higher than the driving power threshold, the electric vehicle is allowed to enter the driving heating mode; if the remaining power of the battery pack is lower than the driving power threshold and higher than the parking power threshold, the electric vehicle is allowed to enter the parking heating mode. Wherein, the driving power threshold is higher than the parking power threshold.

Step S705: whether to heat for driving. If yes, the battery manager needs to further calculate the temperature and remaining power of the battery pack, and execute step S706; if not, execute step S707.

Step S706 includes:

When the temperature of the battery pack is lower than the first temperature threshold, the battery manager sends a message to the instrument indicating that the temperature of the battery pack is too low, and the vehicle is not allowed to be heated, driven and charged.

When the temperature of the battery pack is higher than the first temperature threshold and lower than the second temperature threshold, and the remaining power of the battery pack is higher than the first power threshold, the battery manager controls the battery heater to heat the battery pack, and performs the next step S710: If the remaining power of the battery pack is lower than the first power threshold, execute step S709.

When the temperature of the battery pack is higher than the second temperature threshold and lower than the third temperature threshold, and the remaining power of the battery pack is higher than the second power threshold, the battery manager controls the battery heater to heat the battery pack, and executes the next step S710, wherein the second power threshold is lower than the first power threshold; if the remaining power of the battery pack is lower than the second power threshold, execute step S709.

When the temperature of the battery pack is higher than the third temperature threshold and lower than the fourth temperature threshold, and the remaining power of the battery pack is higher than the third power threshold, the battery manager controls the battery heater to heat the battery pack, and performs the next step S710, wherein the third power threshold is lower than the second power threshold; if the remaining power of the battery pack is lower than the third power threshold, execute step S709.

When the temperature of the battery pack is higher than the fourth temperature threshold and lower than the fifth temperature threshold, and the remaining power of the battery pack is higher than the fourth power threshold, the battery manager controls the battery heater to heat the battery pack, and performs the next step S710, wherein the fourth power threshold is lower than the third power threshold; if the remaining power of the battery pack is lower than the fourth power threshold, execute step S709.

Step 707: Stop heating. Execute the next step S708.

Step S708 includes:

When the temperature of the battery pack is lower than the tenth temperature threshold, the battery manager sends a message to the instrument indicating that the temperature of the battery pack is too low, and the vehicle is not allowed to be heated, driven and charged.

When the temperature of the battery pack is higher than the tenth temperature threshold and lower than the eleventh temperature threshold, and the remaining power of the battery pack is higher than the ninth power threshold, the battery manager controls the battery heater to heat the battery pack, and executes the next step Step S710; if the remaining power of the battery pack is lower than the ninth power threshold, execute step S709.

When the temperature of the battery pack is higher than the eleventh temperature threshold and lower than the twelfth temperature threshold, and the remaining power of the battery pack is higher than the tenth power threshold, the battery manager controls the battery heater to heat the battery pack, and executes the following steps: A step S710, wherein the tenth power threshold is lower than the ninth power threshold; if the remaining power of the battery pack is lower than the tenth power threshold, step S709 is executed.

When the temperature of the battery pack is higher than the twelfth temperature threshold and lower than the thirteenth temperature threshold, and the remaining power of the battery pack is higher than the eleventh power threshold, the battery manager controls the battery heater to heat the battery pack, and executes Next step S710, wherein the eleventh power threshold is lower than the tenth power threshold; if the remaining power of the battery pack is lower than the eleventh power threshold, step S709 is executed.

When the temperature of the battery pack is higher than the thirteenth temperature threshold and lower than the fourteenth temperature threshold, and the remaining power of the battery pack is higher than the twelfth power threshold, the battery manager controls the battery heater to heat the battery pack, and executes Next step S710, wherein the twelfth power threshold is lower than the eleventh power threshold; if the remaining power of the battery pack is lower than the twelfth power threshold, step S709 is executed.

Step S709: The battery manager sends a message to the meter indicating that the remaining power of the battery pack is too low, and the vehicle is not allowed to be heated, driven and charged.

Step S710: self-check whether the battery heater is faulty before heating. If there is no fault, the heating is performed normally, and step S711 is executed; if there is a fault, step S712 is executed.

Step S711: heating the battery pack. During the heating process, step S713 also needs to be executed.

Step S712: The battery heater fails, and the vehicle is not allowed to be heated, driven and charged.

Step S713: Check whether the heating system is faulty. If there is no fault, the heating is performed normally, and step S714 is executed; if there is a fault, step S715 is executed.

Step S714: Whether the heating is completed. If completed, send a CAN message to the battery heater to stop the battery heater, and execute step S716; if not, execute step S711.

Step S715: The heating system fails, and the heating of the battery pack is stopped.

Step S716: Heating ends.

In an example of the present invention, as shown in FIG. 7, the first heating temperature threshold may be -10°C, and the first temperature threshold, the second temperature threshold, the third temperature threshold, the fourth temperature threshold, and the fifth temperature threshold are respectively It can be -30°C, -25°C, -20°C, -15°C, -10°C, and the first power threshold, the second power threshold, the third power threshold, and the fourth power threshold can be 30% of the total power of the battery pack. %, 27.5%, 25%, 22.5%; the tenth temperature threshold, the eleventh temperature threshold, the twelfth temperature threshold, the thirteenth temperature threshold, and the fourteenth temperature threshold can be -30°C, -25°C, -20°C, -15°C, -10°C, the ninth power threshold, the tenth power threshold, the eleventh power threshold, and the twelfth power threshold can be 20%, 17.5%, 15%, or 12.5%.

In another embodiment of the present invention, as shown in FIG. 8, specifically, the battery heating method of an electric vehicle may also include the following steps:

Step S801: Turn ON the electricity on the whole vehicle.

Step S802: Detect whether the temperature of the battery pack is lower than the first heating temperature threshold. The battery manager detects the temperature of the battery pack in the vehicle. If the temperature of the battery pack is higher than the first heating temperature threshold, the battery pack does not need to be heated, and step S803 is executed; if it is lower than the first heating temperature threshold, the power of the battery pack needs to be detected. , execute step S804.

Step S803: the battery manager controls the main contactor in the distribution box to close. Before the main contactor is closed, the battery manager controls the pre-charging contactor to be closed, and after the pre-charging is completed, the main contactor is closed.

Step S804: The battery manager judges whether the heating and driving conditions are met according to the temperature of the battery pack and the remaining power. Specifically, if the remaining power of the battery pack is higher than the driving power threshold, the electric vehicle is allowed to enter the driving heating mode; if the remaining power of the battery pack is lower than the driving power threshold and higher than the parking power threshold, the electric vehicle is allowed to enter the parking heating mode. Wherein, the driving power threshold is higher than the parking power threshold.

Step S805: Whether to heat for driving. If yes, the battery manager needs to further calculate the temperature and remaining power of the battery pack, and execute step S806; if not, execute step S807.

Step S806 includes:

The battery manager judges whether the temperature of the battery pack is higher than the ninth temperature threshold, if yes, and the remaining power of the battery pack is higher than the eighth power threshold, then executes the next step S810, if the remaining power of the battery pack is lower than the eighth power threshold , then execute step S809; if no, the battery manager further judges whether the temperature of the battery pack is higher than the eighth temperature threshold, if yes, and the remaining power of the battery pack is higher than the seventh power threshold, then execute the next step S810, if the battery If the remaining power of the battery pack is lower than the seventh power threshold, step S809 is executed; if not, the battery manager further determines whether the temperature of the battery pack is higher than the seventh temperature threshold, and if so, the remaining power of the battery pack is higher than the sixth power threshold , then execute the next step S810, if the remaining power of the battery pack is lower than the sixth power threshold, then execute step S809; if not, the battery manager further judges whether the temperature of the battery pack is higher than the sixth temperature threshold, if yes, and the battery If the remaining power of the battery pack is higher than the fifth power threshold, execute the next step S810; if the remaining power of the battery pack is lower than the fifth power threshold, execute step S809; if the temperature of the battery pack is lower than the sixth temperature threshold, the battery management The controller sends information to the instrument to show that the temperature of the battery pack is too low, and the vehicle is not allowed to be heated, driven and charged. Wherein, the seventh temperature threshold is higher than the sixth temperature threshold, the eighth temperature threshold is higher than the seventh temperature threshold, the ninth temperature threshold is higher than the eighth temperature threshold; the sixth power threshold is lower than the fifth power threshold, and the seventh power threshold The eighth power threshold is lower than the sixth power threshold, and the eighth power threshold is lower than the seventh power threshold.

Step 807: Stop heating. Execute the next step S808.

Step S808 includes:

The battery manager judges whether the temperature of the battery pack is higher than the eighteenth temperature threshold, if yes, and the remaining power of the battery pack is higher than the sixteenth power threshold, then executes the next step S810, if the remaining power of the battery pack is lower than the tenth threshold Sixth power threshold, then execute step S809; if not, the battery manager further judges whether the temperature of the battery pack is higher than the seventeenth temperature threshold, if yes, and the remaining power of the battery pack is higher than the fifteenth power threshold, then execute the next step Step S810, if the remaining power of the battery pack is lower than the fifteenth power threshold, then execute step S809; if not, the battery manager further judges whether the temperature of the battery pack is higher than the sixteenth temperature threshold, if yes, and the remaining power of the battery pack If the power is higher than the fourteenth power threshold, then execute the next step S810, if the remaining power of the battery pack is lower than the fourteenth power threshold, then execute step S809; if not, the battery manager further determines whether the temperature of the battery pack is higher than The fifteenth temperature threshold, if yes, and the remaining power of the battery pack is higher than the thirteenth power threshold, then perform the next step S810, if the remaining power of the battery pack is lower than the thirteenth power threshold, then perform step S809; if the battery When the temperature of the battery pack is lower than the fifteenth temperature threshold, the battery manager sends a message to the instrument indicating that the temperature of the battery pack is too low, and the vehicle is not allowed to be heated, driven and charged. Among them, the sixteenth temperature threshold is higher than the fifteenth temperature threshold, the seventeenth temperature threshold is higher than the sixteenth temperature threshold, the eighteenth temperature threshold is higher than the seventeenth temperature threshold; the fourteenth power threshold is lower than the tenth Three power thresholds, the fifteenth power threshold is lower than the fourteenth power threshold, and the sixteenth power threshold is lower than the fifteenth power threshold.

Step S809: The battery manager sends a message to the meter indicating that the remaining power of the battery pack is too low, and the vehicle is not allowed to be heated, driven and charged.

Step S810: self-check whether the battery heater is faulty before heating. If there is no fault, the heating is performed normally, and step S811 is executed; if there is a fault, step S812 is executed.

Step S811: heating the battery pack. During the heating process, step S813 also needs to be executed.

Step S812: The battery heater fails, and the vehicle is not allowed to be heated, driven and charged.

Step S813: Check whether the heating system is faulty. If there is no fault, the heating is performed normally, and step S814 is executed; if there is a fault, step S815 is executed.

Step S814: Whether the heating is completed. If completed, send a CAN message to the battery heater to stop the battery heater, and execute step S816; if not, execute step S811.

Step S815: The heating system fails, and the heating of the battery pack is stopped.

Step S816: Heating ends.

In an example of the present invention, as shown in FIG. 8, the first heating temperature threshold may be -10°C, and the sixth temperature threshold, seventh temperature threshold, eighth temperature threshold, and ninth temperature threshold may be -30°C respectively. , -25°C, -20°C, -15°C, the fifth power threshold, the sixth power threshold, the seventh power threshold, and the eighth power threshold can be 30%, 27.5%, 25%, and 22.5% of the total power of the battery pack, respectively. %; the fifteenth temperature threshold, the sixteenth temperature threshold, the seventeenth temperature threshold, and the eighteenth temperature threshold can be -30°C, -25°C, -20°C, -15°C respectively, the thirteenth power threshold, The fourteenth power threshold, the fifteenth power threshold, and the sixteenth power threshold may be 20%, 17.5%, 15%, and 12.5% of the total power of the battery pack, respectively.

According to the battery heating method of an electric vehicle in the embodiment of the present invention, the battery manager can control the battery heater to heat the battery pack in the driving heating mode or the parking heating mode through the real-time temperature and remaining power of the battery pack, and the control accuracy is finer and easier. accomplish.

In one embodiment of the present invention, as shown in FIG. 9, further, the battery heating method of an electric vehicle includes the following steps:

Step S901: Turn ON the electricity on the whole vehicle.

Step S902: Detect the temperature and remaining power of the battery pack.

Step S903: the battery manager controls to close the pre-charging contactor, and after the pre-charging is completed, close the main contactor. The whole vehicle runs according to the normal strategy. Specifically, the battery manager controls the closing of the pre-charging contactor in the distribution box to charge the pre-charging capacitor, and turns off the pre-charging contactor after the pre-charging capacitor is charged.

Step S904: Whether the temperature of the battery pack is lower than the first heating temperature threshold. If yes, execute step S905; if no, execute step S903.

Step S905: the battery manager calculates whether the battery power is higher than the driving power threshold. If yes, execute step S907; if no, execute step S906.

Step S906: the battery manager calculates whether the power is higher than the parking power threshold. If yes, execute step S907; if no, execute step S908. Wherein, the driving power threshold is higher than the parking power threshold.

Step S907: the user confirms whether heating is required. If yes, execute step S909; if no, execute step S910.

Step S908: The battery manager sends a message to the meter indicating that the battery pack is too low, and the vehicle is not allowed to be heated, driven and charged.

Step S909: the battery heater self-checks whether there is any fault before heating. If yes, execute step S911; if no, execute step S912.

Step S910: The battery manager sends a message to the meter indicating that the user is not allowed to heat, and the vehicle is not allowed to be heated, driven and charged.

Step S911: The battery manager stops supplying power to the battery heater and sending messages, and sends a message to the meter to display "heating system failure", and the vehicle is not allowed to be heated, driven and charged.

Step S912: the battery manager sends a heating signal to the battery heater to start heating.

Step S913: The battery manager controls to engage the pre-charging contactor. After the pre-charging is completed and the main contactor is engaged, the vehicle starts heating, and the heating system keeps checking its own state. Specifically, the battery manager receives the starting command input by the driver of the electric vehicle, calculates the current power of the battery pack, calculates the maximum allowable output power of the battery pack, and controls the electric vehicle to run with limited power according to the maximum allowable output power.

Step S914: Whether the user presses the heating button for a preset time. If yes, execute step S915; if no, execute step S920. In an example of the present invention, the preset time may be 2 seconds.

Step S915: Whether the temperature of the battery pack is lower than the nineteenth temperature threshold. If yes, execute step S916; if no, execute step S917.

Step S916: The whole vehicle is not allowed to be heated, driven and charged.

Step S917: Whether the power of the battery pack is higher than the seventeenth power threshold. If yes, execute step S918; if no, execute step S919.

Step S918: Allow the electric vehicle to run with limited power.

Step S919: The battery manager sends a message to the meter indicating that the user stops heating, and the vehicle is not allowed to be heated, driven and charged.

Step S920: Whether the heating system fails during the heating process. If yes, execute step S921; if no, execute step S922.

Step S921: The battery heater stops working, and the instrument displays an alarm. The whole vehicle is not allowed to be heated, driven and charged.

Step S922: Whether the temperature of the battery pack is higher than the first heating temperature threshold. If yes, execute step S925; if no, execute step S923.

Step S923: Whether the temperature of a single battery is higher than the second heating temperature threshold. If yes, execute step S925; if no, execute step S924.

Step S924: Whether the continuous heating exceeds the heating time threshold. If yes, execute step S925; if no, execute step S913.

Step S925: the heating is completed, and the battery heater stops working.

In an example of the present invention, the first heating temperature threshold may be -10°C, the second heating temperature threshold may be 20°C, the nineteenth temperature threshold may be -20°C, and the seventeenth power threshold may be 25% of the electricity, the heating time threshold can be 20 minutes.

In another embodiment of the present invention, as shown in FIG. 10 , further, the battery heating method of an electric vehicle may further include the following steps:

Step S1001: Turn ON the electricity on the whole vehicle.

Step S1002: Detect the temperature and remaining power of the battery pack.

Step S1003: the battery manager controls to close the pre-charging contactor, and controls to close the main contactor after the pre-charging is completed. The whole vehicle runs according to the normal strategy.

Step S1004: Whether the temperature of the battery pack is lower than the first heating temperature threshold. If yes, execute step S1005; if no, execute step S1003.

Step S1005: the battery manager calculates whether the battery power is higher than the driving power threshold. If yes, execute step S1008; if no, execute step S1006.

Step S1006: The battery manager calculates whether the power is higher than the parking power threshold. If yes, execute step S1008; if no, execute step S1007.

Step S1007: The battery manager sends a message to the meter indicating that the battery pack is too low, and the vehicle is not allowed to be heated, driven and charged.

Step S1008: the user confirms whether heating is required. If yes, execute step S1009; if no, execute step S1010.

Step S1009: self-check whether there is a fault in the battery heater before heating. If yes, execute step S1011; if no, execute step S1012.

Step S1010: The battery manager sends a message to the instrument indicating that the user is not allowed to heat, and the vehicle is not allowed to be heated, driven and charged.

Step S1011: The battery manager stops supplying power to the battery heater and sending messages, and sends a message to the instrument showing "heating system failure", and the vehicle is not allowed to be heated, driven and charged.

Step S1012: the battery manager sends a heating signal to the battery heater to start heating.

Step S1013: The battery manager controls to pull in the pre-charging contactor, and after the pre-charging is completed, controls to pull in the main contactor, and then enters into the vehicle heating, and the heating system keeps checking its own state. Specifically, the battery manager receives the starting command input by the driver of the electric vehicle, calculates the current power of the battery pack, calculates the maximum allowable output power of the battery pack, and controls the electric vehicle to run with limited power according to the maximum allowable output power.

Step S1014: Enter different heating processes according to the temperature of the battery pack. The battery manager adjusts the output power of the battery heater according to the temperature of the battery pack, and executes the next step S1015.

Step S1015 specifically includes:

When the temperature of the battery pack is higher than the third heating temperature threshold and lower than the fourth heating temperature threshold, the battery manager controls the battery heater to heat the battery pack with the first power. That is, the output power adjustment module is connected to the first capacitor C11 as shown in FIG. 3A or connected to C.1 as shown in FIG. 3B .

When the temperature of the battery pack is higher than the fourth heating temperature threshold and lower than the fifth heating temperature threshold, the battery manager controls the battery heater to heat the battery pack with the second power, that is, the output power adjustment module is connected as shown in Figure 3A The first capacitor C12 is connected to C.1 and C.2 as shown in FIG. 3B at the same time.

When the temperature of the battery pack is higher than the fifth heating temperature threshold and lower than the sixth heating temperature threshold, the battery manager controls the battery heater to heat the battery pack with the third power, that is, the output power adjustment module is connected as shown in Figure 3A The first capacitor C13 or C.1, C.2 and C.3 in FIG. 3B are connected at the same time.

When the temperature of the battery pack is higher than the sixth heating temperature threshold and lower than the seventh heating temperature threshold, the battery manager controls the battery heater to heat the battery pack with the fourth power. That is, the output power adjustment module is connected to the first capacitor C14 as shown in FIG. 3A or connected to C.1, C.2, C.3 and C.4 as shown in FIG. 3B at the same time.

Step S1016: The battery manager judges whether the instantaneous change of the throttle depth reaches a preset threshold according to the throttle depth message. If yes, execute step S1017; if no, execute step S1019.

Step S1017: The battery heater stops working, and the battery pack only supplies power for the vehicle and the vehicle electrical appliances.

Step S1018: Check whether the uphill or rapid acceleration of the vehicle is over. If yes, execute step S1013; if no, execute step S1017.

Step S1019: the battery manager judges whether the heating time reaches the first preset time (T1). If yes, execute step S1020; if no, execute step S1021.

Step S1020: the battery heater stops working, and the battery manager determines whether the stop time reaches a second preset time (T2). If yes, execute step S1013; if no, continue to execute step S1020.

Step S1021: Whether the user presses the heating button for a preset time. If yes, execute step S1022; if no, execute step S1027. In an example of the present invention, the preset time may be 2 seconds.

Step S1022: Whether the temperature of the battery pack is lower than the nineteenth temperature threshold. If yes, execute step S1023; if no, execute step S1024.

Step S1023: The whole vehicle is not allowed to be heated, driven and charged.

Step S1024: Whether the power of the battery pack is higher than the seventeenth power threshold. If yes, execute step S1025; if no, execute step S1026.

Step S1025: Allow the electric vehicle to run with limited power.

Step S1026: The battery manager sends a message to the instrument indicating that the user stops heating, and the vehicle is not allowed to be heated, driven and charged.

Step S1027: Whether the heating system fails during the heating process. If yes, execute step S1028; if no, execute step S1029.

Step S1028: The battery heater stops working, and the instrument displays an alarm. The whole vehicle is not allowed to be heated, driven and charged.

Step S1029: Whether the temperature of the battery pack is higher than the first heating temperature threshold. If yes, execute step S1032; if no, execute step S1030.

Step S1030: Whether the temperature of a single battery is higher than the second heating temperature threshold. If yes, execute step S1032; if no, execute step S1031.

Step S1031: Whether the continuous heating exceeds the heating time threshold. If yes, execute step S1032; if no, execute step S1013.

Step S1032: the heating is completed, and the battery heater stops working.

In an example of the present invention, the third heating temperature threshold, the fourth heating temperature threshold, the fifth heating temperature threshold, the sixth heating temperature threshold, and the seventh heating temperature threshold may be -30°C, -25°C, -20°C, respectively. °C, -15 °C, -10 °C, the nineteenth temperature threshold can be -20 °C, the seventeenth power threshold can be 25% of the total power of the battery pack, the first heating temperature threshold can be -10 °C, the second heating The temperature threshold may be 20° C., and the heating time threshold may be 20 minutes. The first power is lower than the second power, the second power is lower than the third power, and the third power is lower than the fourth power.

To sum up, specifically, after the vehicle is powered on, the battery manager starts to work, detecting the temperature of the battery pack and the on-off status of the main contactor in the power distribution box. The temperature of the battery pack is the average temperature of the battery pack 101. The battery manager samples the temperature of each battery module in the battery pack through the battery information collector, collects the temperature value of each battery in the battery pack, and calculates the temperature of the battery pack. temperature of all batteries inside. If the temperature of the battery pack is lower than the first heating temperature threshold, and the remaining power of the battery pack is higher than the parking power threshold, and the user presses the heating button for 2 seconds, the battery manager sends a message to the battery heater through the CAN line, Allow the entire vehicle to be heated. Before the driving heating starts, that is, before the motor works, the battery manager sends a control signal to the power distribution box to control the pre-charging contactor to pull in, so that the battery pack charges the pre-charging capacitor C2. When the pre-charging capacitor voltage is close to the battery pack voltage After that, the motor is allowed to work.

Wherein, the heating button is arranged on the instrument panel as a switch for the user to control the battery heater. Press this button to allow the battery heater to work, provided that the temperature of the battery pack is lower than the first heating temperature threshold and the remaining power of the battery pack is higher than the parking power threshold; if the button is pressed again, and Hold for 2 seconds, the battery heater will stop working forcibly.

The main contactor of the distribution box is located inside the distribution box and is used to switch the power supply of the motor controller. If the remaining power is higher than the driving power threshold, the battery manager sends a control signal to the distribution box to control the main contactor to pull in and allow the motor to work. The motor controller inverts the DC power provided by the battery pack into the three-phase AC power required by the motor through the drive circuit, supplies power to the motor, and allows the vehicle to run with limited power.

The pre-charging contactor is also located inside the distribution box and connected in series with the pre-charging capacitor C2. In particular, the precharge capacitor C2 is charged before the motor works because:

1. The pre-charging process can avoid current impact and prevent sintering when the main contactor is closed. A current-limiting resistor is connected in series between the pre-charging capacitor and the pre-charging contactor. When the pre-charging is completed, the battery manager controls the main contactor to pull in, and then disconnects the pre-charging contactor.

2. The starting current of the motor is large in the short period of time just after starting, which will lower the voltage of the entire battery pack. Therefore, charge the pre-charge capacitor C2 first to make its voltage close to the voltage of the battery pack, and then start the motor. Since the voltage of the capacitor cannot change suddenly, it is connected in parallel with the motor to reduce the influence of the motor starting on the voltage of the battery pack.

After the battery heater receives the heating permission signal sent by the battery manager, it starts to self-check its own system, and starts to check whether there is a system failure. In one example of the present invention, the battery heater sends a single 0.5 millisecond pulse to verify that the battery heater is faulty. If no fault is found in the battery heater, the battery heater sends a control pulse (for example, the period is 20 milliseconds, 20% duty cycle) to control the internal switch module circuit, so that the battery pack is short-circuited for a short time to achieve the purpose of heating the battery pack, and at the same time The battery heater sends a CAN signal to the meter, and the meter displays "power battery heating" after receiving the signal.

During the heating process of the battery pack, the battery manager and the battery heater have been detecting the status of the battery pack. Under normal circumstances, if the temperature of the battery pack is detected to be higher than the first heating temperature threshold, or the continuous heating time exceeds the heating time threshold, or If the highest single-cell battery temperature is higher than the second heating temperature threshold, the battery heater stops sending pulse control signals to the switch module, and stops heating the battery pack. The battery heater sends a CAN signal to the instrument, and the instrument displays "heating complete" after receiving the signal, and the heating process of the vehicle battery pack is over at this time. In an example of the present invention, the second heating temperature threshold may be 20° C., and the time threshold may be 20 minutes. Preferably, during the heating process of the battery pack, when it is detected that the temperature of the battery pack is 5° C. higher than the first heating temperature threshold, the heating of the battery pack is stopped.

The work flow under normal trouble-free conditions is as described above.

If the temperature of the battery pack detected by the battery manager is higher than the first heating temperature threshold, the battery manager will work according to the starting strategy of the vehicle at normal temperature; if the battery pack temperature is lower than the first heating temperature threshold and the remaining battery power is lower than When the power threshold of parking is set and the main contactor is not in the state of pull-in, the battery manager will send a CAN signal to the battery heater and the meter, and the battery pack is not allowed to be heated. When the meter receives the signal, it will display "the remaining battery pack is insufficient", and At this time, the whole vehicle is not allowed to be heated, driven and charged.

During the self-test of the battery heater, if any of the battery heater failure, undervoltage protection, overvoltage protection, overheating protection, pulse width interval and maximum on-time protection occurs, the battery pack is not allowed to be heated. The heater sends a fault signal, and the instrument will display "heating system fault" when it receives the signal, and heating is not allowed at this time.

If any of the battery heater failure, undervoltage protection, overvoltage protection, overheat protection, pulse width interval and maximum on-time protection occurs during the battery heater heating the battery pack, the battery heater will stop heating the battery pack. Heating, and sending a fault signal, the instrument will display "heating system fault" when receiving the signal, and the heating of the battery pack will be terminated this time.

In an example of the present invention, for the above-mentioned fault types, further, the protection circuit made inside the battery heater is described as follows:

1) Fault reset circuit. When there is a fault signal, the IGBT is cut off, the internal ERROR (fault) pin is low level, the fault signal is output through the optocoupler, and the pin ERROUT (fault output) is low level. If you want to release the protection state, the PWM (PulseWidthModulation, pulse width modulation) wave should be kept at high level for 2 seconds, the fault signal is reset, and the circuit returns to normal working state. If it cannot be reset within 2 seconds, it means that the circuit has a permanent fault and cannot work normally.

2) Pulse width interval and maximum on-time protection. In order to ensure the normal operation of the internal IGBT discharge module of the battery heater, the pulse frequency sent by DSP (Digital Signal Processor, digital signal processor) should not be too fast, and the pulse width time should not be too long. For example, the maximum pulse width can be 5 milliseconds, and the minimum interval can be 7-10 milliseconds, otherwise there will be a fault signal output.

3) Secondary power generation. In an example of the present invention, the internal IGBT of the battery heater is driven by a DC-DC isolated power supply, the recommended voltage value of the gate positive bias voltage may be +15V, and the negative bias voltage may be -7V. The negative bias speeds up the turn-off of the IGBT and prevents the IGBT from being falsely turned on due to excessive inrush current.

4) Undervoltage protection. The undervoltage protection circuit is mainly to prevent problems such as increased power consumption of the internal IGBT of the battery heater caused by insufficient driving voltage. When the power supply voltage of the internal control circuit of the battery heater drops to the first voltage threshold, the undervoltage protection occurs. In an example of the present invention, the first voltage threshold may be 9V.

5) Over temperature protection. The overheating protection circuit can prevent damage to the IGBT caused by excessive temperature, mainly through temperature sampling through the thermistor, and overheating protection occurs when the temperature of the module bottom plate is higher than the safe temperature threshold. This circuit can also be used to detect whether the thermistor is open circuit, when the thermistor is open circuit, the equivalent resistance is infinite, and the protection signal is output. In an example of the present invention, the safe temperature threshold may be 85°C.

6) Overvoltage protection. Since the discharge circuit usually has a large inductance, when the IGBT is turned off, the collector will excite a very high voltage, so a high-voltage capacitor is connected in parallel between the collector and the emitter of the IGBT. The overvoltage protection module is mainly to prevent the instantaneous collector voltage of the IGBT from being too high when it is turned off, causing the IGBT to be overvoltage and burn out. When the collector voltage exceeds the second voltage threshold, a protection signal is output. In an example of the present invention, the second voltage threshold may be 800V.

During the heating process of the heating system, if the user suddenly presses the heating button and holds it for 2 seconds, the battery heater stops heating the battery pack, and the battery pack is not allowed to be charged, nor is the car allowed to run.

According to the battery heating method of the electric vehicle in the embodiment of the present invention, the pure electric vehicle can realize the heating of the battery pack without relying on the external power supply, so that the temperature of the battery pack can be raised to the required temperature, and then the battery can be used according to the normal discharge and charging strategy. The group greatly reduces the restrictions on the use of electric vehicles in low-temperature environments, and can meet the requirements of customers for driving and charging at low temperatures. At the same time, the battery heating method of the embodiment of the present invention adopts different heating starting methods, and uses different power heating according to the real-time temperature of the battery pack, and the control is more precise, so that the performance of the battery pack can be fully utilized and the safety is improved. In addition, the method of the embodiment of the present invention judges whether the output power of the battery pack is too large by sampling the rate of change of the throttle depth of the electric vehicle, thereby stopping heating the battery pack when the output power of the battery pack is too large, thereby avoiding the battery pack The over-discharge of the electricity improves the service life of the battery pack and ensures the power of the electric vehicle. Heating is carried out at intervals in time, that is, the heating is stopped for a period of time, so that the battery pack is heated periodically, which alleviates the impact of high current on the battery pack and improves the service life of the battery pack.

In the description of this specification, descriptions referring to the terms "one embodiment", "some embodiments", "example", "specific examples", or "some examples" mean that specific features described in connection with the embodiment or example , structure, material or characteristic is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Although the embodiments of the present invention have been shown and described, those skilled in the art can understand that various changes, modifications and substitutions can be made to these embodiments without departing from the principle and spirit of the present invention. and modifications, the scope of the invention is defined by the appended claims and their equivalents.

Claims (45)

1. A power system of an electric vehicle, comprising: Battery; a battery heater, the battery heater is connected to the battery pack, and the battery heater is configured to charge and discharge the battery pack to heat the battery pack, wherein the battery heater has An output power adjustment module, the output power adjustment module is used to adjust the charging current and/or discharge current of the battery pack to adjust the heating power of the battery pack, and the battery heater will detect results are sent to said battery manager; a battery manager, the battery manager is respectively connected to the battery pack and the battery heater, and is used for parking when the temperature of the battery pack is lower than the first heating temperature threshold and the remaining power of the battery pack is higher than After the power threshold, the battery heater is adjusted according to the temperature of the battery pack and the remaining power to heat the battery pack in different heating start modes, and is controlled by the output power adjustment module according to the temperature of the battery pack The battery heater heats the battery pack with a corresponding heating power, and controls the battery heater to heat the battery pack at intervals; a distribution box, the distribution box is used to distribute the voltage output by the battery pack; motor; A motor controller, the motor controller is respectively connected to the motor and the distribution box, and the motor controller has a first input end, a second input end, and a connection between the first input end and the second input end. A pre-charging capacitor between two input terminals, the motor controller is used to supply power to the motor according to the control command and the voltage distributed by the distribution box; and An isolation inductor, the isolation inductor is connected between the battery pack and the distribution box, and the inductance value of the isolation inductor matches the pre-charging capacity of the motor controller. 2. The power system of an electric vehicle according to claim 1, wherein when the remaining power of the battery pack is higher than the threshold value of the driving power, the electric vehicle is allowed to enter the driving heating mode, wherein the driving power The threshold is higher than the parking power threshold. 3. The power system of an electric vehicle according to claim 2, wherein the battery manager controls the battery heater to heat the battery pack when any one of the following conditions is met: The temperature of the battery pack is higher than the first temperature threshold and lower than the second temperature threshold, and the remaining power of the battery pack is higher than the first power threshold; The temperature of the battery pack is higher than the second temperature threshold and lower than the third temperature threshold, and the remaining power of the battery pack is higher than the second power threshold, and the second power threshold is lower than the first power threshold threshold; The temperature of the battery pack is higher than the third temperature threshold and lower than the fourth temperature threshold, and the remaining power of the battery pack is higher than the third power threshold, and the third power threshold is lower than the second power threshold Threshold; or The temperature of the battery pack is higher than the fourth temperature threshold and lower than the fifth temperature threshold, and the remaining power of the battery pack is higher than the fourth power threshold, and the fourth power threshold is lower than the third power threshold threshold. 4. The power system of an electric vehicle according to claim 2, wherein the battery manager controls the battery heater to heat the battery pack when any of the following conditions is satisfied: The temperature of the battery pack is higher than the sixth temperature threshold, and the remaining power of the battery pack is higher than the fifth power threshold; The temperature of the battery pack is higher than a seventh temperature threshold, and the remaining power of the battery pack is higher than a sixth power threshold, wherein the seventh temperature threshold is higher than the sixth temperature threshold, and the sixth power the threshold is lower than the fifth power threshold; The temperature of the battery pack is higher than the eighth temperature threshold, and the remaining power of the battery pack is higher than the seventh power threshold, wherein the eighth temperature threshold is higher than the seventh temperature threshold, and the seventh power the threshold is lower than the sixth power threshold; or The temperature of the battery pack is higher than the ninth temperature threshold, and the remaining power of the battery pack is higher than the eighth power threshold, wherein the ninth temperature threshold is higher than the eighth temperature threshold, and the eighth power The threshold is lower than the seventh power threshold. 5. The power system of an electric vehicle according to claim 3 or 4, wherein when the remaining power of the battery pack is lower than the driving power threshold and higher than the parking power threshold, the electric power is allowed to The car goes into parking heating mode. 6. The power system of an electric vehicle according to claim 5, wherein the battery manager controls the battery heater to heat the battery pack when any one of the following conditions is met: The temperature of the battery pack is higher than the tenth temperature threshold and lower than the eleventh temperature threshold, and the remaining power of the battery pack is higher than the ninth power threshold; The temperature of the battery pack is higher than the eleventh temperature threshold and lower than the twelfth temperature threshold, and the remaining power of the battery pack is higher than the tenth power threshold, and the tenth power threshold is lower than the first Nine power thresholds; The temperature of the battery pack is higher than the twelfth temperature threshold and lower than the thirteenth temperature threshold, and the remaining power of the battery pack is higher than the eleventh power threshold, and the eleventh power threshold is lower than the thirteenth temperature threshold the above tenth power threshold; or The temperature of the battery pack is higher than the thirteenth temperature threshold and lower than the fourteenth temperature threshold, and the remaining power of the battery pack is higher than the twelfth power threshold, and the twelfth power threshold is lower than the The eleventh power threshold is described above. 7. The power system of an electric vehicle according to claim 5, wherein the battery manager controls the battery heater to heat the battery pack when any one of the following conditions is met: The temperature of the battery pack is higher than a fifteenth temperature threshold, and the remaining power of the battery pack is higher than a thirteenth power threshold; The temperature of the battery pack is higher than the sixteenth temperature threshold, and the remaining power of the battery pack is higher than the fourteenth power threshold, wherein the sixteenth temperature threshold is higher than the fifteenth temperature threshold, so The fourteenth power threshold is lower than the thirteenth power threshold; The temperature of the battery pack is higher than the seventeenth temperature threshold, and the remaining power of the battery pack is higher than the fifteenth power threshold, wherein the seventeenth temperature threshold is higher than the sixteenth temperature threshold, so the fifteenth power threshold is lower than the fourteenth power threshold; or The temperature of the battery pack is higher than the eighteenth temperature threshold, and the remaining power of the battery pack is higher than the sixteenth power threshold, wherein the eighteenth temperature threshold is higher than the seventeenth temperature threshold, so The sixteenth power threshold is lower than the fifteenth power threshold. 8. The power system of an electric vehicle according to claim 1, wherein the battery manager is further configured to control the battery heater to heat the battery pack, if the driver presses the heating button again button, then judge whether the operation of pressing the heating button again satisfies the preset condition, if judged to be satisfied, then further control the electric vehicle and/or the battery heater according to the temperature and remaining power of the battery pack . 9. The power system of the electric vehicle as claimed in claim 8, characterized in that, If the temperature of the battery pack is lower than a nineteenth temperature threshold, the battery manager issues a prompt to prohibit heating, driving or charging of the electric vehicle; and If the temperature of the battery pack is higher than the nineteenth temperature threshold, the battery manager controls the battery heater to stop heating the battery pack. 10. The power system of the electric vehicle as claimed in claim 9, characterized in that, If the remaining power of the battery pack is lower than the seventeenth power threshold, the battery manager issues a prompt to prohibit heating, driving or charging of the electric vehicle; and If the remaining power of the battery pack is higher than the seventeenth power threshold and the temperature of the battery pack is higher than the nineteenth temperature threshold, the battery manager allows the electric vehicle to run with limited power. 11. The power system of an electric vehicle according to claim 8, wherein the battery manager is also used to judge whether the current rate of change of the throttle depth of the electric vehicle has reached a preset threshold, and when it is judged that the rate of change of the throttle depth has reached the preset threshold, When the preset threshold is exceeded, the battery heater is controlled to stop heating the battery pack. 12. The power system of an electric vehicle according to claim 11, wherein the battery manager is further used to determine that when the current throttle depth change rate of the electric vehicle is lower than the preset threshold value, control the The battery heater continues to heat the battery pack. 13. The power system of an electric vehicle according to claim 1, wherein the battery manager is further configured to judge whether the heating time reaches a first preset time, and when it is judged that the heating time reaches the first preset time, time, control the battery heater to stop heating the battery pack. 14. The power system of an electric vehicle according to claim 13, wherein the battery manager is further configured to calculate the stop time after controlling the battery heater to stop heating the battery pack, and When the stop time reaches a second preset time, the battery heater is started again to heat the battery pack. 15. The power system of an electric vehicle according to claim 1, wherein, If the temperature of the battery pack is higher than a third heating temperature threshold and lower than a fourth heating temperature threshold, the battery manager controls the battery heater to heat the battery pack with a first power; If the temperature of the battery pack is higher than the fourth heating temperature threshold and lower than the fifth heating temperature threshold, the battery manager controls the battery heater to heat the battery pack with a second power; If the temperature of the battery pack is higher than the fifth heating temperature threshold and lower than the sixth heating temperature threshold, the battery manager controls the battery heater to heat the battery pack with a third power; or If the temperature of the battery pack is higher than the sixth heating temperature threshold and lower than the seventh heating temperature threshold, the battery manager controls the battery heater to heat the battery pack with a fourth power. 16. The power system of an electric vehicle according to claim 1, wherein the inductance L of the isolation inductor is determined according to the following formula: Wherein, T is the equivalent load duty cycle of the motor, and C is the capacitance value of the precharge capacitor. 17. The power system of an electric vehicle according to claim 1, wherein the battery heater further comprises: a first switch module, one end of the first switch module is respectively connected to the first electrode of the battery pack and the isolation inductor; At least one first capacitor, one end of the at least one first capacitor is connected to the other end of the first switch module, and the other end of the at least one first capacitor is connected to the second electrode of the battery pack; a first inductor, one end of the first inductor is connected to a node between the first switch module and the at least one first capacitor; A second switch module, one end of the second switch module is connected to the other end of the first inductor, and the other end of the second switch module is connected to the second electrode of the battery pack, the first switch The control terminals of the module and the second switch module are connected to the battery manager, and when the battery pack is heated, the battery manager sends a signal to the battery heater, and the battery heater controls the first A switch module and a second switch module are turned on sequentially to generate charging current and discharge current in the battery pack sequentially, and the second switch module is turned off when the first switch module is turned on, and the second switch module is turned off when the second switch module is turned on. The first switch module is turned off when the switch module is turned on. 18. The power system of an electric vehicle according to claim 17, wherein the output power adjustment module is used to adjust the output pulses of the first switch module and the second switch module according to the instructions of the battery manager duty cycle. 19. The power system of an electric vehicle according to claim 17, wherein there are multiple first capacitors, and the output power adjustment module is used to adjust the connected capacitors according to the instructions of the battery manager. The number of the first capacitor. 20. The power system of an electric vehicle according to claim 19, wherein the output power adjustment module is a relay. 21. The power system of an electric vehicle according to claim 17, wherein the battery heater further comprises: The cooling assembly is used for cooling the first switch module and the second switch module in the battery heater. 22. The power system of an electric vehicle according to claim 21, wherein the cooling assembly further comprises: an air duct provided in the battery heater; and A fan arranged at one end of the air duct. 23. The power system of an electric vehicle according to claim 21, wherein the cooling assembly further comprises: a coolant channel provided in the battery heater; and A coolant inlet and a coolant outlet are provided on the battery heater. 24. The power system of an electric vehicle according to claim 1, wherein the battery heater further comprises: The power connector is used to connect and fix the power line connected with the battery pack. 25. The power system of an electric vehicle according to claim 1, wherein the distribution box further comprises: a main contactor for distributing the output voltage of the distribution box to electrical equipment of the electric vehicle under the control of the battery manager; and A pre-charging contactor, the pre-charging contactor is connected to one of the first input end and the second input end of the motor controller, and the pre-charging contactor is used to, under the control of the battery manager, The motor controller controls the motor to charge the pre-charge capacitor before starting. 26. An electric vehicle, characterized by comprising the power system of the electric vehicle according to any one of claims 1-25. 27. A battery heating method for an electric vehicle according to claim 26, characterized in that it comprises the following steps: detecting the temperature of the battery pack and the remaining power of the battery pack; If the temperature of the battery pack is lower than a first heating temperature threshold and the remaining charge of the battery pack is higher than a parking charge threshold, the battery manager adjusts the battery heater according to the temperature and remaining charge of the battery pack The battery pack is heated in different heating starting modes, and the battery heater is controlled by the output power adjustment module according to the temperature of the battery pack to heat the battery pack with the corresponding heating power, and the output power adjustment module is controlled to heat the battery pack The battery heater heats the battery pack at intervals; If the temperature of the battery pack is lower than the first heating temperature threshold and the remaining power of the battery pack is lower than the parking power threshold, the battery manager issues a warning to prohibit heating, driving or charging of the electric vehicle reminder; and If the temperature of the battery pack is higher than the first heating temperature threshold, the battery manager controls the main contactor in the distribution box to close. 28. The battery heating method of an electric vehicle according to claim 27, wherein when the remaining power of the battery pack is higher than a driving power threshold, the electric vehicle is allowed to enter a driving heating mode, wherein the driving The power threshold is higher than the parking power threshold. 29. The battery heating method of an electric vehicle according to claim 28, wherein the battery manager controls the battery heater according to the current vehicle state of the electric vehicle, the temperature of the battery pack and the remaining power heating said battery pack in a predetermined manner, further comprising: When the temperature of the battery pack is higher than the first temperature threshold and lower than the second temperature threshold, and the remaining power of the battery pack is higher than the first power threshold, the battery manager controls the battery heater to The battery pack is heated; When the temperature of the battery pack is higher than the second temperature threshold and lower than the third temperature threshold, and the remaining power of the battery pack is higher than the second power threshold, the battery manager controls the battery heater heating the battery pack, wherein the second power threshold is lower than the first power threshold; When the temperature of the battery pack is higher than the third temperature threshold and lower than the fourth temperature threshold, and the remaining power of the battery pack is higher than the third power threshold, the battery manager controls the battery heater heating the battery pack, wherein the third charge threshold is lower than the second charge threshold; or When the temperature of the battery pack is higher than the fourth temperature threshold and lower than the fifth temperature threshold, and the remaining power of the battery pack is higher than the fourth power threshold, the battery manager controls the battery heater The battery pack is heated, wherein the fourth power threshold is lower than the third power threshold. 30. The battery heating method of an electric vehicle according to claim 28, wherein the battery manager controls the battery heater according to the current vehicle state of the electric vehicle, the temperature of the battery pack and the remaining power heating said battery pack in a predetermined manner, further comprising: When the temperature of the battery pack is higher than the sixth temperature threshold and the remaining power of the battery pack is higher than the fifth power threshold, the battery manager controls the battery heater to heat the battery pack; When the temperature of the battery pack is higher than the seventh temperature threshold and the remaining power of the battery pack is higher than the sixth power threshold, the seventh temperature threshold is higher than the sixth temperature threshold, and the sixth power threshold When it is lower than the fifth power threshold, the battery manager controls the battery heater to heat the battery pack; When the temperature of the battery pack is higher than the eighth temperature threshold and the remaining power of the battery pack is higher than the seventh power threshold, the eighth temperature threshold is higher than the seventh temperature threshold, and the seventh power threshold When it is lower than the sixth power threshold, the battery manager controls the battery heater to heat the battery pack; or When the temperature of the battery pack is higher than the ninth temperature threshold and the remaining power of the battery pack is higher than the eighth power threshold, the ninth temperature threshold is higher than the eighth temperature threshold, and the eighth power threshold When it is lower than the seventh power threshold, the battery manager controls the battery heater to heat the battery pack. 31. The battery heating method of an electric vehicle according to claim 29 or 30, characterized in that, when the remaining power of the battery pack is lower than the driving power threshold and higher than the parking power threshold, allowing the The electric car goes into parking heating mode. 32. The battery heating method of an electric vehicle according to claim 31, wherein the battery manager controls the battery heater according to the current vehicle state of the electric vehicle, the temperature of the battery pack and the remaining power heating said battery pack in a predetermined manner, further comprising: When the temperature of the battery pack is higher than the tenth temperature threshold and lower than the eleventh temperature threshold, and the remaining power of the battery pack is higher than the ninth power threshold, the battery manager controls the battery heater to the battery pack is heated; When the temperature of the battery pack is higher than the eleventh temperature threshold and lower than the twelfth temperature threshold, and the remaining power of the battery pack is higher than the tenth power threshold, the battery manager controls the battery The heater heats the battery pack, wherein the tenth power threshold is lower than the ninth power threshold; When the temperature of the battery pack is higher than the twelfth temperature threshold and lower than the thirteenth temperature threshold, and the remaining power of the battery pack is higher than the eleventh power threshold, the battery manager controls the A battery heater heats the battery pack, wherein the eleventh power threshold is lower than the tenth power threshold; or When the temperature of the battery pack is higher than the thirteenth temperature threshold and lower than the fourteenth temperature threshold, and the remaining power of the battery pack is higher than the twelfth power threshold, the battery manager controls the The battery heater heats the battery pack, wherein the twelfth power threshold is lower than the eleventh power threshold. 33. The battery heating method of an electric vehicle according to claim 31, wherein the battery manager controls the battery heater according to the current vehicle state of the electric vehicle, the temperature of the battery pack and the remaining power heating said battery pack in a predetermined manner, further comprising: When the temperature of the battery pack is higher than the fifteenth temperature threshold and the remaining power of the battery pack is higher than the thirteenth power threshold, the battery manager controls the battery heater to heat the battery pack ; When the temperature of the battery pack is higher than the sixteenth temperature threshold and the remaining power of the battery pack is higher than the fourteenth power threshold, the battery manager controls the battery heater to heat the battery pack , wherein the sixteenth temperature threshold is higher than the fifteenth temperature threshold, and the fourteenth power threshold is lower than the thirteenth power threshold; When the temperature of the battery pack is higher than the seventeenth temperature threshold and the remaining power of the battery pack is higher than the fifteenth power threshold, the battery manager controls the battery heater to heat the battery pack , wherein the seventeenth temperature threshold is higher than the sixteenth temperature threshold, and the fifteenth power threshold is lower than the fourteenth power threshold; or When the temperature of the battery pack is higher than the eighteenth temperature threshold and the remaining power of the battery pack is higher than the sixteenth power threshold, the battery manager controls the battery heater to heat the battery pack , wherein the eighteenth temperature threshold is higher than the seventeenth temperature threshold, and the sixteenth power threshold is lower than the fifteenth power threshold. 34. The battery heating method of an electric vehicle according to claim 27, further comprising: after the battery manager controls the battery heater to heat the battery pack: After the driver presses the heating button again, it is judged whether the operation of pressing the heating button again meets the preset condition; If it is determined that the preset condition is met, the electric vehicle and/or the battery heater are further controlled according to the temperature and remaining power of the battery pack. 35. The battery heating method of an electric vehicle according to claim 34, wherein: If the temperature of the battery pack is lower than a nineteenth temperature threshold, the battery manager issues a prompt to prohibit heating, driving or charging of the electric vehicle; and If the temperature of the battery pack is higher than the nineteenth temperature threshold, the battery manager controls the battery heater to stop heating the battery pack. 36. The battery heating method of an electric vehicle according to claim 35, wherein: If the remaining power of the battery pack is lower than the seventeenth power threshold, the battery manager issues a prompt to prohibit heating, driving or charging of the electric vehicle; and If the remaining power of the battery pack is higher than the seventeenth power threshold and the temperature of the battery pack is higher than the nineteenth temperature threshold, the battery manager allows the electric vehicle to run with limited power. 37. The battery heating method of an electric vehicle according to claim 27, further comprising: The battery manager judges whether the current rate of change of the throttle depth of the electric vehicle reaches a preset threshold; If it is determined that the preset threshold is reached, the battery manager controls the battery heater to stop heating the battery pack; and If it is determined that the preset threshold has not been reached, the battery manager controls the battery heater to continue heating the battery pack. 38. The battery heating method of an electric vehicle according to claim 27, wherein the controlling the battery heater according to the heating time further comprises: judging whether the heating time reaches a first preset time; and When it is judged that the first preset time is reached, the battery heater is controlled to stop heating the battery pack. 39. The battery heating method of an electric vehicle according to claim 38, further comprising: Calculate the stop time; judging whether the stop time reaches a second preset time; and When it is judged that the second preset time is reached, the battery heater is activated again to heat the battery pack. 40. The battery heating method of an electric vehicle according to claim 27, further comprising: If the temperature of the battery pack is higher than a third heating temperature threshold and lower than a fourth heating temperature threshold, the battery manager controls the battery heater to heat the battery pack with a first power; If the temperature of the battery pack is higher than the fourth heating temperature threshold and lower than the fifth heating temperature threshold, the battery manager controls the battery heater to heat the battery pack with a second power; If the temperature of the battery pack is higher than the fifth heating temperature threshold and lower than the sixth heating temperature threshold, the battery manager controls the battery heater to heat the battery pack with a third power; or If the temperature of the battery pack is higher than the sixth heating temperature threshold and lower than the seventh heating temperature threshold, the battery manager controls the battery heater to heat the battery pack with a fourth power. 41. The battery heating method of an electric vehicle according to claim 27, further comprising: before the battery manager controls the battery heater to heat the battery pack: The battery manager controls the pre-charging contactor in the distribution box to close to charge the pre-charging capacity, and turns off the pre-charging contactor after the pre-charging capacity is charged. 42. The battery heating method of an electric vehicle according to claim 27, further comprising: The battery heater sends the detection result to the battery manager after performing a fault self-check, and when the battery heater fails, the battery manager issues a prompt to prohibit heating, driving or charging of the electric vehicle. 43. The battery heating method of an electric vehicle according to claim 27, further comprising: before the battery manager controls the battery heater to heat the battery pack: judging whether a heating command input by the driver of the electric vehicle is received; If the heating instruction is received, the battery manager controls the battery heater to heat the battery pack; and If the heating instruction is not received, the battery manager issues a prompt to prohibit heating, driving or charging of the electric vehicle. 44. The battery heating method of an electric vehicle according to claim 27, further comprising: after the battery manager controls the battery heater to heat the battery pack: The battery manager receives a starting instruction input by a driver of the electric vehicle; the battery manager calculates the current temperature and remaining capacity of the battery pack, and calculates the maximum allowable output power of the battery pack; and The electric vehicle is controlled to run with limited power according to the maximum allowable output power. 45. The battery heating method of an electric vehicle according to claim 27, wherein the battery manager controls the battery heater to stop heating when any one of the following conditions is satisfied, the battery pack temperature is higher than the first heating temperature threshold; The temperature of any single battery in the battery pack is higher than a second heating temperature threshold, and the second heating temperature threshold is higher than the first heating temperature threshold; or The continuous heating time of the battery heater is higher than the heating time threshold.