CN107139747A - Electric automobile - Google Patents

Abstract

The invention discloses an electric vehicle, comprising a main body; a battery pack accommodating portion; at least one rechargeable battery pack accommodated in the battery pack accommodating portion, the rechargeable battery pack including several battery sub-units; a voltage detection unit for for respectively detecting the voltages of a plurality of battery subunits; and a control unit, configured to receive the voltages of each battery subunit detected by the voltage detection unit, and compare the voltage signal of each battery subunit with a safety voltage threshold, Cut off the connection of the battery subunit exceeding the safe voltage threshold to the battery pack. The invention is beneficial in that it reduces the risk of reverse charging when the battery subunit supplies power, and improves the safety of the electric vehicle.

Description

electric car

technical field

The invention relates to an electric vehicle.

Background technique

As the power source of electric vehicles, the battery device in electric vehicles has always restricted the development of electric vehicles. When driving high-power electric vehicles, it often causes the problem of insufficient power and poor battery life.

When the battery device is adapted to a higher-power electric vehicle, more rechargeable cells are needed, but when the rechargeable cells in an electric vehicle are often unbalanced, the rechargeable cells or battery packs with weaker power are prone to failure. Reverse charging will cause potential safety hazards.

Contents of the invention

In order to achieve the above object, the present invention adopts the following technical solutions:

An electric vehicle, comprising a main body; a battery pack accommodating portion; at least one rechargeable battery pack accommodated in the battery pack accommodating portion, the rechargeable battery pack comprising several battery subunits, the battery subunit comprising at least 2 Rechargeable battery cells, wherein the battery subunits are configured the same and include an equal number of rechargeable battery cells; a voltage detection unit is used to respectively detect the voltages of a plurality of the battery subunits; and a control unit is used to receive The voltage detection unit detects the voltage of each battery subunit, compares the voltage signal of each battery subunit with a safety voltage threshold, and when the voltage value of at least one of the battery subunits exceeds the safety voltage threshold, cut off the voltage exceeding the safety voltage threshold. The connection of the battery subunit to the battery pack for the voltage threshold.

Further, the control unit is configured to receive the voltage of each battery subunit detected by the voltage detection unit, and calculate the voltage difference between each of the battery subunits within a preset time, where the voltage difference When the preset difference is exceeded, the safety voltage threshold of the battery pack is adjusted.

Further, the control unit calculates the voltage difference between the battery subunits within the preset time, and the voltage difference is the maximum value of the voltage difference between a plurality of the battery subunits.

Further, the control unit reduces the preset time when the voltage difference exceeds the preset difference.

Further, the battery subunit includes two rechargeable batteries connected in parallel.

The invention is beneficial in that it reduces the risk of reverse charging when the rechargeable battery pack supplies power to the electric vehicle, and improves the safety of the electric vehicle. At the same time, by dynamically adjusting the safety voltage threshold, it is possible to more accurately ensure the safety of electric vehicle battery packs.

Description of drawings

Fig. 1 is the schematic diagram of an embodiment of electric vehicle;

Figure 2 is a schematic block diagram of an embodiment of a battery pack;

FIG. 3 is a schematic block diagram of an embodiment of a battery pack used to implement a voltage detection section.

detailed description

As shown in FIG. 1 , an electric vehicle includes a main body, a battery pack accommodating portion, and at least one rechargeable battery pack accommodated in the battery pack accommodating portion (not shown).

2 to 3, the electric vehicle or battery pack 100 includes: a rechargeable cell pack 11, a battery pack interface or interface 12, a temperature unit 13, a voltage detection unit 14, a communication unit 15, and a control unit 16 .

The rechargeable battery pack 11 includes: more than one battery sub-unit 111 . When the battery subunit 111 includes at least two rechargeable batteries, different battery subunits 111 are connected to each other, and the whole formed by them is the rechargeable battery pack 11 .

A battery subunit 111 includes: at least 2 rechargeable batteries. The number of rechargeable cells in the same battery subunit 111 is equal and the connection methods are equal, and different rechargeable cells are connected in parallel to form a battery subunit 111 . As an implementation manner, as shown in FIG. 2 , one battery subunit 111 includes two rechargeable batteries connected in parallel. Here, the battery pack can expand the battery capacity by adding a rechargeable battery pack, which can be adapted to more powerful electric vehicles.

The battery pack interface 12 is electrically connected to the rechargeable battery pack 11 and the control unit 16 respectively, and is provided with a positive terminal and a negative terminal for connecting with the outside world to realize electric energy or signal transmission. When the battery pack supplies power to the electric device 200 , the battery pack interface 12 keeps the rechargeable cells in the rechargeable cell pack 11 in a discharge state, and can also provide power for other modules and components inside the battery pack.

The temperature unit 13 includes: a temperature measuring part 131 and a temperature signal module 132, wherein the temperature measuring part 131 is used to detect the internal temperature of the rechargeable battery pack. The temperature measuring element 131 is arranged inside the electric vehicle or the battery pack 100 close to the rechargeable battery cells, so that it can detect the change of the temperature of the rechargeable battery cells. Specifically, the temperature measuring element 131 may be a thermistor, such as an NTC thermistor.

The temperature signal module 132 is electrically connected to the temperature measuring element 131 and the control unit 16 respectively, and can send the detection result of the temperature measuring element 131 to the control unit 16 and be controlled by the control unit 16 . The temperature signal module 132 is provided with a temperature terminal T for electrical connection with an external temperature terminal.

The voltage detection unit 14 is used to detect the voltage value of each battery subunit 111 in the rechargeable battery pack 11 , and the voltage detection unit 14 is electrically connected to the rechargeable battery pack 11 and the control unit 16 respectively.

The voltage detection unit 14 detects the voltage signal in the rechargeable battery pack 11 and transmits the voltage signal to the control unit 16, and the control unit 16 calculates the voltage value of each battery subunit 111 according to the voltage signal input by the voltage detection unit 14, so as to realize Voltage safety monitoring of rechargeable battery packs.

The communication unit 15 is used for exchanging data or signals, and is electrically connected with the control unit 16 . The communication unit 15 can implement data transmission through hardware connection or wireless connection. Due to the high voltage and output power of the rechargeable battery pack, it has high requirements for reliability and safety when it is connected to an electrical device.

As shown in FIG. 2 to FIG. 3 , in one embodiment of the present invention, the battery pack and the electric device adopt a hardware connection to realize the transmission of electric energy and data. The communication unit 15 is provided with a communication terminal D. When the battery pack is assembled with the electric vehicle, the communication terminal D can form a physical connection with the corresponding terminal in the electric vehicle.

The control unit 16 is mainly used to implement functions such as logic operations and process control. It can control each component and module in the electric vehicle to ensure the safety of the battery pack in the electric vehicle when charging and discharging.

The voltage detection unit 14 will be mainly introduced below. The voltage detection unit 14 is mainly used to respectively detect the voltage signal of the high voltage terminal of the battery subunit 111 . Specifically, the voltage detection unit 14 includes a detection circuit 143 , one end of the detection circuit 143 is connected to the high voltage end of the battery subunit 111 , and the other end is connected to the control unit 16 .

In other embodiments of the present invention, in order to detect multiple battery subunits 111 , the voltage detection unit 14 further includes a time-sharing module 146 . The function of the time-sharing module 146 is to control the detection circuit 143, which can at least control the detection circuit 143 to make its two ends disconnect or make its two ends conduct.

Referring to Fig. 2, multiple detection circuits 143 are connected and then connected to the control unit 16 through the same line. Multiple detection circuits 143 connected together serve as a detection group 141 , and multiple detection circuits 143 in one detection group 141 send the collected voltage signals to the control unit 16 through the same bus under the control of the same time-sharing module 146 . The time-sharing module 146 is electrically connected to the control unit 16 , and the control unit 16 can control the time-sharing module 146 , and then indirectly control the time-sharing conduction of multiple detection circuits 143 .

Generally, there are multiple battery subunits 111 in the rechargeable battery pack 11 , and in order to realize comprehensive detection, the voltage detection unit 14 is provided with multiple detection circuits 143 or a total voltage detection center. The control unit 16 simultaneously receives voltage signals from multiple detection circuits 143 or a total voltage detection center.

Further, the detection circuit 143 includes an on-off element 144, the on-off element 144 includes two connection terminals and a control terminal (not shown), wherein the two connection terminals are divided into: connected to the detection terminal 144a of the battery subunit 111 and an output for connection to the control unit 16 . The control terminal receives the signal from the time-sharing module 146 and controls the two connection terminals of the on-off element to be turned on or off.

Referring to FIG. 2 , the on-off elements 144 in the detection circuits 143 in the same detection group 141 are finally connected to the same place, and then connected to the control unit 16 .

The detection circuit 143 also includes a voltage dividing resistor 145, and the voltage dividing resistor 145 can be connected to the output end 144b side of the on-off element 144 as shown in Figure 3, or can be connected to the detection end 144a side of the on-off element 144 .

The control process of the control unit 16 when the rechargeable cell pack or the battery pack is used to supply power to the electrical device of the electric vehicle will be described in detail below with reference to FIG. 2 and FIG. 3 .

As shown in Figure 3, the rechargeable cells are continuously discharged when the battery pack is discharged, and each battery subunit 111 may have uneven discharge. If the rechargeable cell is over-discharged, the control unit 16 stores a safety voltage threshold to prevent over-discharge of the battery subunit voltage.

Specifically, the voltage detection unit 14 respectively detects the voltage signal of each battery subunit 111, and the control unit 16 is used to receive the voltage signal of each battery subunit 111 detected by the voltage detection unit 14, and convert each battery subunit The voltage signal of 111 is compared with the safety voltage threshold of the battery subunit, and when the voltage value of one of the battery subunits 111 exceeds the safety voltage threshold, the battery subunit 111 and the battery that exceeds the safety voltage threshold are cut off. set of connections.

In one embodiment of the present invention, the battery pack interface 12 further includes a switch unit, the switch unit is electrically connected to the control unit 16, and when the voltage value of one of the battery subunits 111 exceeds the safe voltage threshold, the control unit 16 outputs the The switch unit disconnects the control signal to cut off the connection between the battery subunit 111 and the battery pack, so that the battery subunit 100 is no longer discharged externally, so as to ensure the safety of the electric vehicle 100 .

When the voltage values of the battery subunits 111 do not exceed the safe voltage threshold, the battery subunits 111 in the battery pack include at least two rechargeable batteries connected in parallel. When the discharge of the two rechargeable batteries is unbalanced, Since the rechargeable cells are connected in parallel, when one of the rechargeable cell units is over-discharged, the voltage of the battery sub-unit 111 detected by the voltage detection unit 14 will remain substantially unchanged in a short time. If the rechargeable battery pack continues to discharge, the rechargeable battery cells in the battery sub-unit 111 will be flooded and other hazards will occur, which will damage the rechargeable battery cells that have been over-discharged.

Therefore, the control unit 16 is further configured to make the voltage difference between each of the battery subunits 111 within a preset time, and if the voltage difference exceeds the preset difference, the control unit 16 outputs a signal to adjust the safety voltage threshold. control signal. In the present invention, each rechargeable battery cell in the battery sub-units has approximately the same voltage parameter when leaving the factory; otherwise, the method of comparing the voltage difference between each of the battery sub-units with the preset difference is adopted invalidated.

For example, the voltages of the two cells in the first battery subunit are U1 and U2 respectively, and the voltages of the two cells in the second battery subunit are U3 and U4 respectively. Since the voltage parameters of each rechargeable cell are roughly the same when they leave the factory , after a discharge process, the difference between the first battery subunit and the second battery subunit is the difference between the rechargeable cells in the first battery subunit and the second battery subunit, such as the first battery If the voltage difference ΔUi between the subunit and the second battery subunit exceeds the preset difference, the control unit 16 outputs a control signal that increases the safety voltage threshold to modify or adjust the safety voltage threshold of the battery subunit .

For battery packs composed of array cells for electric vehicles, by dynamically adjusting the actual safety voltage threshold of the battery pack, identifying and cutting off the operation of abnormal cell battery subunits, it is possible to more accurately ensure the safety of large battery packs for electric vehicles. Electrical Safety.

In one embodiment of the present invention, the method for adjusting the safety voltage threshold of the battery subunit is as follows:

S1. Detect the voltage value Ui of each battery subunit 111;

S2. Determine whether the voltage value Ui of each battery subunit 111 is less than the safety voltage threshold U; if so, go to step S3; otherwise go to step S8;

S3. Calculate the voltage difference ΔUi between each battery subunit 111 within a preset time;

S4. Compare the magnitude of each voltage difference to obtain the maximum voltage difference △Umax;

S5. Determine whether the maximum voltage difference △Umax is greater than the preset difference, if so, continue to execute S6; otherwise, return to S2;

S6. Increase or adjust the safety voltage threshold, and continue to execute step S7;

S7. Decrease the preset time and continue to execute step S2;

S8. Disconnect the electrical connection between the battery sub-unit 111 that is less than the safety voltage threshold U and the battery pack.

It should be noted that, in some other embodiments of the present invention, the safety voltage threshold and the preset time can be increased at the same time, without chronological order; the safety voltage threshold and the preset time can also be adjusted together, in This is not limiting. In this way, the detection efficiency of detecting whether the rechargeable battery is over-discharged can be further improved, and the battery pack and/or the electric vehicle 100 can be protected.

The basic principles, main features and advantages of the present invention have been shown and described above. Those skilled in the industry should understand that the above-mentioned embodiments do not limit the present invention in any form, and all technical solutions obtained by means of equivalent replacement or equivalent transformation fall within the protection scope of the present invention.

Claims (5)

1. a kind of electric automobile, including：

Main body；

Battery pack receiving portion；

At least one rechargeable battery pack, is contained in the battery pack receiving portion, if the rechargeable battery pack includes dry cell Subelement, the battery subelement includes the chargeable battery core of at least two, wherein, described each battery subelement set it is identical and Chargeable battery core including equal number；

Voltage detection unit, the voltage for detecting multiple battery subelements respectively；

Control unit, for receiving each battery subelement voltage that the voltage detection unit detection is obtained, by each battery The voltage signal of subelement is made comparisons with safe voltage threshold values, and the magnitude of voltage of at least one of which battery subelement exceedes safety electricity During pressure valve value, this is cut off more than the battery subelement of safe voltage threshold values and the connection of battery pack；

Wherein, each chargeable battery core in the battery subelement, has roughly the same voltage parameter when dispatching from the factory.

2. electric automobile according to claim 1, it is characterised in that described control unit, for receiving the voltage inspection Survey obtained each battery subelement voltage of unit detection, and calculate between each described battery subelement in preset time Voltage difference, the safe voltage thresholds of the battery pack are adjusted when the voltage difference exceedes preset difference value.

3. electric automobile according to claim 1, it is characterised in that

Described control unit calculates the voltage difference between the battery subelement in the preset time, the voltage difference For the maximum of the voltage difference between multiple battery subelements.

4. electric automobile according to claim 3, it is characterised in that

Described control unit reduces the preset time when the voltage difference exceedes the preset difference value.

5. electric automobile according to claim 1, it is characterised in that

The battery subelement includes two chargeable battery cores in parallel.