JP7064692B2 - A method for determining the state of a power storage device, a management device, and a power storage device. - Google Patents

Description

The technique disclosed herein relates to a technique for determining the state of a power storage device.

Vehicles such as automobiles are equipped with a power source for in-vehicle electrical components and a power storage device used as a drive source for the vehicle. The power storage device generally includes a plurality of power storage elements, and the deterioration state of these power storage elements can be estimated by measuring the internal resistance of the power storage elements. For this reason, the power storage device may be provided with a management device that calculates the internal resistance by measuring the current and voltage.

The measured value of the internal resistance of the power storage element is affected by the usage status of the power storage element. For example, when a large current is flowing, the temperature of the power storage element rises, and the measured value of the internal resistance is affected by the temperature rise of the power storage element. Immediately after the energization is completed, it is known that the terminal voltage of the power storage element deviates from the correct value due to the polarization phenomenon inside the power storage element, and the deviation of the terminal voltage also causes an error in the measured value of the internal resistance. This polarization phenomenon disappears with the passage of time and reaches a stable state unless a large current flows.

Conventionally, when it is detected that the power storage device is in a non-current state, the elapsed time is counted by a timer from the time when the power storage device is detected to be in a non-current state, and when a predetermined time has elapsed, the power storage element A technique has been developed in which the internal resistance is measured on the assumption that the current has reached a stable state, and the state of the power storage element is estimated based on the internal resistance (for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2006-149070

According to the above technique, whether or not the power storage element has reached a stable state is determined based on the elapsed time count regardless of the usage status of the power storage element before the time when the power storage device is detected to be in a non-current state. Deciding. When the power storage element is energized only for a short time, it is necessary to wait until a predetermined time elapses even though the power storage element returns to a stable state in a short time.

The technique disclosed herein aims to make it possible to determine whether or not a power storage element is in a stable state without relying on time counting by a timer.

The power storage device has first and second temperature measuring units that measure the temperatures of the two parts, respectively, and the power storage element is based on the temperature difference of each temperature acquired from the first and second temperature measuring units by the management device. Judge the state of.

In this configuration, it can be determined that the state of the power storage element is stable without relying on the time count by the timer.

Side view of the vehicle in the first embodiment Perspective view of power storage device An exploded perspective view of the power storage device Block diagram showing the electrical configuration of the power storage device A flowchart showing the flow of processing for determining the stable state of the temperature of the power storage element. A block diagram showing an electrical configuration of the power storage device according to the second embodiment. A block diagram showing an electrical configuration of the power storage device according to the third embodiment. A block diagram showing an electrical configuration of the power storage device according to the fourth embodiment. Partial notch side view showing the power storage element according to the fifth embodiment A graph showing the time course of the temperature of two different batteries in the power storage device.

<Outline of Embodiment>
The power storage device disclosed in the present specification is a first and second temperature measuring unit that measures the temperature of two parts of the power storage device, respectively, and each temperature acquired from these first and second temperature measuring units. It is provided with a management device that determines the state of the power storage element based on the temperature difference.

When a current flows through the power storage element of the power storage device, heat is generated inside the power storage element and the internal temperature rises. When the current is cut off, the heat generation stops, and the temperature of the entire power storage device gradually decreases due to heat diffusion and heat dissipation to the outside. In this case, since the thermal conditions are variously different in different parts of the power storage device, how the temperature changes with the passage of time is not uniform, and the temperature difference may be large depending on the place. Immediately after the end of energization, even if the temperature difference between places is large, the temperature difference decreases with the passage of time, and finally the whole reaches thermal equilibrium.

FIG. 10 shows an example of changes in temperature of two power storage elements at different parts of the power storage device when the power storage device is energized for a predetermined time, then the power supply is stopped, and the power storage device is left unattended. The curve indicated by the reference numeral P indicates a temperature change of the power storage element in a portion of the power storage device where heat is relatively difficult to dissipate. The curve indicated by the reference numeral Q indicates the temperature change of the power storage element in the portion where heat is relatively easily dissipated.

When the power storage device is energized, the temperature of the power storage element in the portion where heat is difficult to dissipate rises faster than the temperature of the power storage element in the portion where heat is easily dissipated. That is, a temperature difference occurs between a portion where heat is difficult to dissipate and a portion where heat is easily dissipated. After that, the amount of heat generated by energization and the amount of heat dissipated are balanced, so that the temperature of each part goes to equilibrium with a temperature difference left. When the energization of the power storage device is stopped (time indicated by the symbol R), the temperature of each part gradually decreases due to heat diffusion and heat dissipation to the outside, the temperature difference becomes smaller, and finally the overall temperature. Towards thermal equilibrium where are equal.

The temperature is measured by the first and second temperature measuring units at the two parts of the power storage device, and the power storage element of the power storage device is based on the fact that the temperature difference between the first and second temperature measuring units reaches a predetermined range. The state of can be determined.

Even if the power storage device that has not been used for a long time starts charging / discharging, the power storage element of the power storage device remains stable as long as the temperature difference between the first and second temperature measuring units remains within a predetermined range. It can be determined that there is. When a current flows through the power storage element for a short time and there is no significant change in the temperature distribution inside the power storage device or the state inside the power storage element, the temperature difference in each temperature measuring unit does not increase, so the state is stable at an early stage. It can be determined.

At least one of the first and second temperature measuring units may be provided so as to measure the temperature of the power storage element, and the other may measure the temperature of a portion of the power storage device separated from the power storage element. According to this configuration, when the temperature of the power storage element becomes close to the temperature of the part away from this, that is, the environmental temperature of the power storage element, the temperature difference between the two temperature measuring parts becomes small, so that the temperature difference between the two temperature measuring parts becomes Based on this, the state of the power storage element can be determined.

According to this configuration, since the state of the power storage element is determined based on the temperature difference between the two parts of the power storage device, a timer for continuously counting the time after the power storage device becomes non-current is unnecessary. Can be. Even when the management device of the power storage device has to shift to the low power consumption state while the vehicle is parked, the power consumption can be suppressed because the timer that needs to be continuously operated is not used.

The power storage device is installed in a place that is easily affected by the outside temperature, or the engine of the vehicle is near the power storage device. If is provided, there is a possibility of erroneous judgment just by monitoring with a timer as in the conventional case. For example, if the temperature condition of the place where the power storage device is placed changes irregularly due to the influence of the outside air temperature or the thermal influence of the engine, it is assumed that the power storage element has reached the stable state by the count of the timer. However, it may not be possible to say that the temperature of the power storage element is still high and has reached a stable state. In addition, when a part of the power storage device becomes hotter than the others due to the outside air temperature or the thermal influence of the engine, even if it is considered that the power storage element has reached a stable state by the timer count, it is actually It cannot be said that the entire power storage element is thermally stable.

According to this configuration, since the state of the power storage element is determined based on the temperature difference between the two parts of the power storage device, erroneous determination due to an irregular thermal influence from the outside is unlikely to occur.

When the internal resistance of the power storage element is estimated according to the determination that it is in a stable state and the temperature of the power storage element is further corrected, the temperature correction can be performed based on the temperature with little variation. The accuracy can be improved. This will be described in detail below. Since the internal resistance of the power storage element is temperature-dependent, it is common practice to perform temperature correction when estimating the internal resistance of the power storage element. If the temperatures of multiple power storage elements are not stable and the temperature of each power storage element varies, the accuracy of estimating the internal resistance of the power storage elements will decrease because it is not known at which temperature the correction should be made. There is a risk of According to this configuration, it is possible to determine whether or not the temperature of the power storage element is stable, so that it is possible to improve the accuracy of temperature correction of the internal resistance of the power storage element, and the internal resistance of the power storage element can be accurately adjusted. Can be estimated.

In the above power storage device, when a plurality of the power storage elements are integrated to form an assembled battery, each of the first and second temperature measuring units may measure the temperature of a different power storage element among the assembled batteries. can.

According to this configuration, the state of the power storage element can be determined based on the bias of the temperature of each power storage element in the entire assembled battery. Therefore, the assembled battery is particularly configured by integrating the power storage elements of the same type and the same capacity. If so, the state of the power storage element can be determined more accurately. In this case, it is preferable that the first and second temperature measuring units are provided on the power storage element located at the center of the assembled battery and the power storage element located at the end of the assembled battery.

The first and second temperature measuring units may be provided at different parts of the same power storage element. Even for the same power storage element, the deviation of the internal temperature and how the temperature changes over time are closely related to the stability of the power storage element, so the temperature difference between different parts of the same power storage element. The state of the power storage element can be determined based on the above.

When the power storage device is mounted on a vehicle equipped with an internal combustion engine started by cranking, the management device determines the state of the power storage element on condition that a signal for executing cranking of the internal combustion engine is received. Is preferable.

According to the above configuration, the state of the power storage element is determined immediately before cranking. Therefore, when it is determined that the power storage element is in a stable state immediately before the crank, the current flowing during the subsequent cranking is used. The internal resistance can be estimated. Therefore, since the internal resistance is estimated with a large current, the accuracy when estimating the internal resistance of the power storage element can be improved.

<Embodiment 1>
The first embodiment will be described with reference to FIGS. 1 to 5. For a plurality of the same members, a reference numeral may be added to only one member, and the reference numerals may be omitted for the other members.
1. 1. Description of the power storage device 10 As shown in FIG. 1, the vehicle 1 includes a power storage device 10. As shown in FIG. 2, the power storage device 10 has a box-shaped battery case 31, and the battery case 31 houses an assembled battery 14 composed of a plurality of batteries 11 (power storage elements) and a control board 38. Has been done. In the following description, when referring to FIGS. 2 and 3, the vertical direction of the battery case 31 when the battery case 31 is placed horizontally without tilting with respect to the installation surface is the Y direction, and the long side of the battery case 31 is used. The direction along the direction will be described as the X direction, and the depth direction of the battery case 31 will be described as the Z direction.

As shown in FIG. 3, the battery case 31 includes a case body 33 that opens upward, a positioning member 34 that positions a plurality of batteries 11, an inner lid 35 that is mounted on the upper part of the case body 33, and an upper lid 36. It is configured with. As shown in FIG. 3, a plurality of cell chambers 33A in which each battery 11 is individually housed are provided in the case main body 33 side by side in the X direction.

As shown in FIG. 3, the positioning member 34 has a plurality of bus bars 37 arranged on the upper surface thereof, and the positioning member 34 is arranged on the upper portions of the plurality of batteries 11 arranged in the case main body 33, whereby a plurality of positioning members 34 are arranged. Batteries 11 are positioned and connected in series by a plurality of bus bars 37.

As shown in FIG. 2, the inner lid 35 has a substantially rectangular shape in a plan view. A pair of terminal portions 32P and 32N to which harness terminals (not shown) are connected are provided at both ends of the inner lid 35 in the X direction. The pair of terminal portions 32P and 32N are made of a metal such as a lead alloy, 32P is a positive electrode side terminal portion and 32N is a negative electrode side terminal portion.

An accommodating portion 35A is provided on the upper surface of the inner lid 35. The control board 38 is housed inside the housing portion 35A of the inner lid 35, and the battery 11 and the control board 38 are connected by mounting the inner lid 35 on the case main body 33. Further, the upper lid 36 is attached to the upper part of the inner lid 35 and closes the upper surface of the accommodating portion 35A accommodating the control board 38.

The electrical configuration of the power storage device 10 will be described with reference to FIG. The power storage device 10 includes a battery 11, a temperature measuring unit 15 (corresponding to a first temperature measuring unit), a reference temperature measuring unit 13 (corresponding to a second temperature measuring unit), and a management device 16.

The assembled battery 14 is composed of a plurality of (four in this embodiment) batteries 11 having the same capacity connected in series. The plurality of batteries 11 are arranged in a parallel direction (direction indicated by the arrow A).

The battery 11 has, for example, a flat rectangular parallelepiped shape, and is a so-called square battery. The battery 11 contains a storage element (not shown) in a metal case 12. As the battery 11, for example, a lithium ion secondary battery using an iron phosphate-based material for the positive electrode and graphite for the negative electrode can be used, but the battery 11 is not limited to the above configuration.

The battery voltage of the battery 11 is about 3.5V, the total voltage of the assembled battery 14 is about 14V, and the voltage class of the power storage device 10 is 12V. The power storage device 10 is exemplified as a device for starting an engine 2 which is an internal combustion engine for driving a vehicle.

A reference temperature measuring unit 13 is attached to the outer surface of the battery 11A located at one end (upper end in FIG. 4) in the parallel direction among the plurality of batteries 11 constituting the assembled battery 14. Of the plurality of batteries 11 constituting the assembled battery 14, the temperature measuring unit is on the outer surface of the battery 11B (third from the upper end and second from the lower end in FIG. 4) located at the center in the parallel direction. 15 is attached. As the reference temperature measuring unit 13 and the temperature measuring unit 15, known temperature measuring members such as a thermistor and a thermocouple can be used. A thermistor is used in this embodiment.

When the number of batteries 11 is an odd number (2n-1 and n is a natural number), the central portion of the assembled battery 14 refers to the nth battery 11 counted from both ends of the assembled battery 14. When the number of batteries 11 is an even number (2n, n is a natural number), the nth battery 11 counting from one end of the assembled battery 14 and the nth battery 11 counting from the other end. Refers to at least one of the batteries 11. In the present embodiment, the number of batteries 11 constituting the assembled battery 14 is four (even numbers), so that in FIG. 4, the second battery 11B counted from the lower end of the assembled battery 14 is located at the center in the parallel direction. It is designed to be located.

Since the battery 11A to which the reference temperature measuring unit 13 is attached is located at the end of the assembled battery 14, heat is easily dissipated to the outside. Therefore, when the power storage device 10 is energized, the temperature change (difference between the equilibrium temperature on the low temperature side and the equilibrium temperature on the high temperature side) is the smallest among the batteries 11 constituting the assembled battery 14.

Since the battery 11B to which the temperature measuring unit 15 is attached is located in the central portion of the assembled battery 14, the heat generated during energization is less likely to be dissipated. Therefore, when the power storage device 10 is energized, it is one of the batteries 11 constituting the assembled battery 14 having the largest temperature change (difference between the equilibrium temperature on the low temperature side and the equilibrium temperature on the high temperature side).

The power storage device 10 includes a management device 16 that manages the assembled battery 14. The management device 16 includes a CPU 17 (an example of a computer) which is a central processing device, a memory 18, and a communication unit 19.

The reference temperature measuring unit 13 and the temperature measuring unit 15 described above are electrically connected to the management device 16 by a signal line 20. The reference temperature, which is the temperature of the battery 11A measured by the reference temperature measuring unit 13, and the measured temperature, which is the temperature of the battery 11B measured by the temperature measuring unit 15, are taken into the management device 16.

The memory 18 is, for example, a non-volatile memory such as a flash memory or an EEPROM. The memory 18 stores a program for managing the battery 11 and data necessary for executing the program. Further, in the memory 18, a program that calculates a temperature difference between the reference temperature and the measured temperature and determines whether or not the temperature difference between the reference temperature and the measured temperature is smaller than a predetermined reference value, or the above-mentioned The reference value of is stored.

The CPU 17 acquires the reference temperature from the reference temperature measuring unit 13 and the measured temperature from the temperature measuring unit 15, and calculates the temperature difference between the two temperatures.

The power storage device 10 is connected to the starter motor 25 and the charging device 26 via the power supply line 22 and the ground line 23. The starter motor 25 and the charging device 26 are controlled by the vehicle ECU 27 (Electronic Control Unit). The vehicle ECU 27 is connected to the communication unit 19 of the management device 16 via the communication line 28, and communication is possible between the two.

When the ignition switch 24 is turned on and a signal for executing cranking is given to the vehicle ECU 27, the starter motor 25 is energized by the signal from the vehicle ECU 27 and performs the cranking to start the engine 2 which is an internal combustion engine. conduct.

The charging device 26 charges the assembled battery 14. In this embodiment, the charging device 26 includes a generator driven by the engine 2 of the vehicle. The charging device 26 may receive electric power from an external power source arranged outside the vehicle 1.

The management device 16 determines the state of the battery 11 based on the output of the temperature measuring unit 15 and the output of the reference temperature measuring unit 13 as described below.

2. 2. Process for determining the state of the battery 11 FIG. 5 is a flowchart of a process for determining the state of the battery 11 by the management device 16. When the ignition switch 24 is turned on, the vehicle ECU 27 receives the signal and executes the process of FIG. 5 prior to driving the starter motor 25.

The CPU 17 acquires the reference temperature T2 from the reference temperature measuring unit 13 (S10), and acquires the measured temperature T1 from the temperature measuring unit 15 (S20). The CPU 17 calculates the temperature difference ΔT (= | T2-T1 |) between the measured temperature T1 and the reference temperature T2, and compares this temperature difference ΔT with the reference value Tref stored in the memory 18 in advance (S30).

When the temperature difference ΔT is equal to or less than the reference value Tref, the CPU 17 determines that the stable state has been reached with no temperature bias between the batteries 11, sets the stable state flag (S40), and ends the process. When the reference value Tref is exceeded, the process ends without setting the same flag. After that, the CPU 17 immediately executes cranking by the starter motor 25 to start the engine 2.

When the stable state flag is set, the CPU 17 acquires the current flowing during subsequent cranking and the terminal voltage of the battery 11, and calculates the internal resistance of the battery 11 based on the terminal voltage of the battery 11. The CPU 17 has already acquired the temperatures T1 and T2 of the battery 11 at the time when the stable state flag is set, and the temperature difference ΔT between the temperatures T1 and T2 of the battery 11 is relatively small (ΔT ≦ Tref), so that the battery 11 The calculated internal resistance is converted into the internal resistance at a predetermined standard temperature (temperature correction) using the temperature T1 or T2 of the above, and the internal resistance at the standard temperature is calculated. Since the internal resistance at this standard temperature reflects the deteriorated state of the battery 11, the CPU 17 determines the deteriorated state of the battery 11 or the assembled battery 14 by taking into account the information of the internal resistance at the standard temperature, or the life of the battery 11. Make a judgment.

According to this configuration, the management device 16 determines the state of the battery 11 based on the temperature difference ΔT between the measured temperature T1 and the reference temperature T2, so that the timer is activated by detecting that the battery 11 has become a non-current state. It is possible to determine the state without measuring the elapse of a predetermined time.

Therefore, it is not necessary to continuously start the timer, and each temperature T1 and T2 may be acquired when necessary. Therefore, the system of the power storage device 10 may be turned off, or an event may occur intermittently or somehow. It is also possible to obtain a low power consumption state such as acquiring each temperature T1 and T2 at times.

In the present embodiment, a plurality of batteries 11 are integrated to form the assembled battery 14, the reference temperature measuring unit 13 measures the temperature of the battery 11A constituting the assembled battery 14, and the temperature measuring unit 15 measures the battery 11A. The temperature of the battery 11B different from that of the battery 11B is measured.

The thermal conditions of the batteries 11 arranged at different positions in the assembled battery 14 are different. Therefore, when the assembled battery 14 is energized, a temperature difference may occur between different batteries 11. According to this configuration, the state of the battery 11 can be determined based on the temperature difference between the batteries 11A and 11B in the entire assembled battery 14, so that the assembled battery 14 in particular integrates the batteries 11 of the same type and the same capacity. When configured, the state of the battery 11 can be determined more accurately.

In the present embodiment, the reference temperature measuring unit 13 measures the temperature of the battery 11A located at the end of the assembled battery 14, and the temperature measuring unit 15 measures the temperature of the battery 11B located at the center of the assembled battery 14. As described above, the battery 11A tends to have the highest temperature among the batteries 11 constituting the assembled battery 14 when the power storage device 10 is energized. On the other hand, when the power storage device 10 is energized, the battery 11B is less likely to reach a high temperature among the batteries 11 constituting the assembled battery 14. Therefore, the temperature difference between the battery 11A and the battery 11B is considered to be the largest among the various temperature differences between the four batteries 11 constituting the assembled battery 14.

Therefore, the state of the assembled battery 14 can be accurately determined by using the temperature difference between the other batteries 11.

When it is determined that the temperature difference ΔT between the reference temperature T2 of the battery 11A and the measured temperature T1 of the battery 11B is equal to or less than the reference value Tref, the temperature bias of the battery 11 constituting the assembled battery 14 is small. Means that. Therefore, by using the reference temperature T2 of the battery 11A or the measured temperature T1 of the battery 11B acquired by the management device 16, the temperature correction of the internal resistance of the battery 11 can be accurately performed.

The predetermined reference value Tref, which is the threshold of the temperature difference ΔT between the measurement temperature T1 and the reference temperature T2, is the number of batteries 11 included in the assembled battery 14, the arrangement of the batteries 11, the structure of the battery 11, and the assembled battery 14. An appropriate value is set according to the presence or absence of a device for cooling. The reference value Tref (threshold value) can be set by conducting an experiment in advance. As in the present embodiment, in the configuration in which the reference temperature measuring unit 13 is arranged at the end in the parallel direction and the temperature measuring unit 15 is arranged at the center position of the assembled battery 14, the reference value Trf is 1. ° C or lower is preferable, and 0.5 ° C or lower is even more preferable.

The power storage device 10 is mounted on the vehicle 1 on which the engine 2 started by cranking is mounted, and the management device 16 receives a signal for executing the cranking of the engine 2 of the battery 11. Determine the state. As a result, the management device 16 determines the state of the battery 11 immediately before cranking. When it is determined that the battery 11 is in a stable state immediately before cranking, it is preferable to estimate the internal resistance by using the current flowing during cranking.

Since a relatively large current flows through the power storage device 10 during cranking of the engine 2, the accuracy of calculating the internal resistance of the battery 11 can be improved.

When it is determined that the state of the battery 11 is stable, the internal resistance of the battery 11 can be estimated accurately even when the vehicle 1 is running.

<Modification example>
Next, a modification of the present embodiment will be described. The ignition switch 24 has an accessory position, an on position, and a start position. When the ignition switch 24 is set to the accessory position, the power of an in-vehicle accessory device such as a radio or an audio device is turned on. When the ignition switch 24 is set to the on position, the power of the ignition system device of the engine 2 is turned on. When the ignition switch 24 is set to the start position, a signal for executing cranking is transmitted.

When the ignition switch 24 is set to the accessory position or the on position, the vehicle ECU 27 orders the CPU 17 of the management device 16 to execute a process of determining the state of the battery 11. Since the process for determining the state of the battery 11 and the subsequent processes are the same as those in the first embodiment, the overlapping description will be omitted.

In this way, the state of the battery 11 may be determined in a state where the occupant does not start the engine 2 and the ignition switch 24 is set to the accessory position or the on position and the radio, audio equipment, or the like is used.

<Embodiment 2>
The second embodiment will be described with reference to FIG. In the power storage device 40 according to the present embodiment, cold air is blown to the assembled battery 14 along the direction indicated by the arrow line B. The cold air may be separated from the cold air generated by the air conditioner of the vehicle 1, or may be cold air from a dedicated cooling device. Further, the outside air introduced from the outside of the vehicle 1 may be used.

The battery 11A arranged at the uppermost portion in FIG. 6 is most easily cooled by cold air. Therefore, when the power storage device 40 is energized, the temperature change (the speed at which the temperature drops) is the smallest among the batteries 11 constituting the assembled battery 14. A reference temperature measuring unit 13 is arranged on the outer surface of the battery 11A.

The battery 11C arranged at the lowermost part in FIG. 6 is located on the leeward side of the cold air, and therefore has the lowest cooling efficiency. Therefore, when the power storage device 40 is energized, the temperature change (the speed at which the temperature drops) is the largest among the batteries 11 constituting the assembled battery 14. A temperature measuring unit 15 is arranged on the outer surface of the battery 11C.

Since the configurations other than the above are substantially the same as those in the first embodiment, the same members are designated by the same reference numerals, and duplicate description will be omitted.

In the present embodiment, the temperature difference between the battery 11A and the battery 11C is the largest among the temperature differences between the batteries 11 constituting the assembled battery 14. In the present embodiment, the state of the battery 11 is determined based on the temperature difference between the battery 11A and the battery 11C. Therefore, when it is detected that the temperature difference between the battery 11A and the battery 11C is equal to or less than a predetermined reference value, It means that all the temperature differences between the other batteries 11 constituting the assembled battery 14 are smaller than the predetermined reference value. Therefore, even if the reference value is set relatively large in consideration of the detection error, the comparison error, and the like, the state of each battery 11 can be accurately determined.

<Embodiment 3>
In the power storage device 50 according to the present embodiment, as shown in FIG. 7, the reference temperature measuring unit 13 is arranged in the management device 16. Specifically, the management device 16 is provided inside the battery case 31 of the power storage device 50, and the reference temperature measuring unit 13 is arranged on the control board 38 constituting the management device 16. The CPU 17 acquires the temperature T2 inside the management device 16 measured by the reference temperature measuring unit 13 as the reference temperature.

Since the configurations other than the above are substantially the same as those in the first embodiment, the same members are designated by the same reference numerals, and duplicate description will be omitted.

When the management device 16 is provided inside the battery case 31 of the power storage device 50, the temperature environment of the management device 16 is substantially the same as the temperature environment of the assembled battery 14. Even if the temperature of the assembled battery 14 rises due to charging / discharging, when the charging / discharging is completed and the temperature of the assembled battery 14 drops, the temperature becomes close to the internal temperature of the management device 16. As a result, the temperature of the temperature measuring unit 15 provided in the battery 11 of the assembled batteries 14 becomes close to the temperature of the reference temperature measuring unit 13 measuring the internal temperature of the management device 16, and eventually, the temperature measuring unit Since the temperature difference between 15 and the reference temperature measuring unit 13 becomes small, it is determined that the assembled battery 14 is in a stable state when the temperature difference becomes equal to or less than the reference value Tref.

According to this configuration, for example, when the external environmental temperature of the power storage device 50 is high, the internal temperature of the assembled battery 14 and the management device 16 is also high, and the temperature difference ΔT between the temperature measuring units 13 and 15 is affected by the environmental temperature. Since the value is obtained by excluding the above, the accuracy of the state determination of the battery 11 can be improved.

<Embodiment 4>
The fourth embodiment will be described with reference to FIG. The vehicle 1 according to the present embodiment is an electric vehicle equipped with a power storage device 60, and travels by a motor driven by electric power from the power storage device 60. The engine 2 and the starter motor 25 are not mounted on the vehicle 1. A power switch 61 is arranged in place of the ignition switch 24. The charging device 26 receives power from an external power source provided outside the vehicle 1 to charge the power storage device 60.

When the system of the vehicle 1 is activated by turning on the power switch 61, the vehicle ECU 27 orders the CPU 17 of the management device 16 to execute a process of determining the state of the battery 11.

Since the configurations other than the above are substantially the same as those in the first embodiment, the same members are designated by the same reference numerals, and duplicate description will be omitted.

When the system of the vehicle 1 is turned on, the management device 16 acquires the temperature T1 of the battery 11B from the temperature measuring unit 15 and the temperature T2 of the battery 11A from the reference temperature measuring unit 13 as in the first embodiment. The management device 16 determines the state of the battery 11 of the power storage device 60 from the temperature difference ΔT between the measured temperature T1 acquired from the temperature measuring unit 15 and the reference temperature T2 acquired from the reference temperature measuring unit 13. After that, as in the first embodiment, when it is determined that the power storage device 60 is in a stable state, the internal resistance of the battery 11 is estimated and the temperature of the battery 11 is corrected.

<Modification example>
In the fourth embodiment, the state of the power storage device 60 is determined when the power switch 61 of the electric vehicle is turned on. However, in the modification of the fourth embodiment described below, immediately before the power storage device 60 is charged. , The state of the battery 11 is determined.

When the external power supply is connected to the charging device 26, the vehicle ECU 27 determines that the power storage device 60 is in a chargeable state, and executes a process of determining the state of the battery 11 of the power storage device 60 in the management device 16. Order to do. Thereby, as in the fourth embodiment, the temperatures T1 and T2 are acquired, the temperature difference ΔT is calculated, and the ΔT is compared with the reference value Tref stored in the memory 18 in advance. When the temperature difference ΔT is equal to or less than the reference value Tref, the stable state flag is set to end the process, and when the temperature difference ΔT exceeds the reference value Tref, the process ends without setting the same flag. After that, the CPU 17 charges the power storage device 60 by the charging device 26.

According to the present embodiment, the management device 16 determines the state of the battery 11 immediately before charging the power storage device 60. If it is determined that the battery 11 is in a stable state immediately before charging, the internal resistance can be estimated by using the current flowing during charging. When charging the power storage device 60, a relatively large current flows through the power storage device 60, so that the accuracy of estimating the internal resistance of the battery 11 can be improved.

<Embodiment 5>
The fifth embodiment will be described with reference to FIG. In the battery 71 of the present embodiment, the power storage element 74 is housed inside the case 72. The reference temperature measuring unit 73 is attached to the outer surface of the upper wall of the case 72 of the battery 71 and measures the temperature T2 of the outer surface of the battery 71.

The temperature measuring unit 75 is attached to the inside of the case 72 of the battery 71. The temperature measuring unit 75 is arranged at a position slightly above the lower wall of the case 72. The temperature measuring unit 75 can be arranged at any part inside the case 72 as needed. The temperature measuring unit 75 measures the temperature T1 inside the battery 71. The temperature measuring unit 75 may measure the temperature of the power storage element 74 or may measure the temperature of the inner surface of the case 72. The temperature measuring unit 75 measures the temperature of any member arranged inside the case 72.

Even with one battery 71, the calorific value and heat dissipation are different for each part, so that the internal temperature may be biased or a temperature difference may occur between the internal temperature and the external temperature immediately after energization. The bias in the internal temperature and the temperature difference between the inside and the outside are reduced by the passage of time after the end of energization, and finally reach thermal equilibrium.

Since the bias of the internal temperature of the battery 71 and how the temperature of the battery 71 changes with the passage of time are closely related to the stable state of the battery 71, the temperature of different parts of the same battery 71 is measured. The state of the battery 71 can be determined based on the temperature difference.

<Other embodiments>
The techniques disclosed herein are not limited to the embodiments described above and in the drawings. For example, the following embodiments are also included in the scope of the art disclosed herein.

(1) In the first to fourth embodiments, the first and second temperature measuring units are arranged in two different power storage elements among the plurality of power storage elements constituting one power storage device. Not limited to this, among the plurality of power storage elements constituting one power storage device, a temperature measuring unit is arranged for each of three or more different power storage elements, and three or more power storage elements in which the temperature measuring unit is arranged are arranged. The state of the power storage element may be determined based on the temperature difference between the two power storage elements selected from the above. The fact that it is based on the temperature difference between the two power storage elements is not limited to determining the magnitude relationship between the temperature difference ΔT and the reference value Tref as shown in the above-described embodiment, and for example, mathematical processing is added to the temperature difference ΔT. It includes calculating the value and making a judgment based on the value.

(2) The first and second temperature measuring units may be an NTC thermistor, a PTC thermistor, a thermoelectric pair, or the like, or may be a non-contact type temperature sensor.

(3) The power storage element according to the first to fifth embodiments has a square shape, but is not limited to this, and may be a cylindrical shape or a bag shape formed by joining a laminated film.

(4) The power storage devices 10, 40, and 60 according to the first to third embodiments are configured to be mounted on the vehicle 1 in which the engine 2 is used as a power source, and the power storage device 50 according to the fourth embodiment is used by a motor as a power source. However, the technique disclosed in the present specification is not limited to this, and the technique disclosed in the present specification is a vehicle (for example, HEV) in which an engine and a motor are used as a power source, or a forklift, an electric tool, and a smartphone. , PC, and other devices that use batteries, and can be applied to systems that require battery stability determination.

(5) The power storage device according to the first to fifth embodiments is configured to include four power storage elements, but the present invention is not limited to this, and one power storage device may be configured to include one power storage element. Further, the configuration may include two to three or five or more power storage elements.

(6) Measure the temperature of two parts of the power storage device whose temperature changes depending on the charge and discharge of the power storage element, such as the terminal part to which the harness terminal is connected, the control board, and the bus bar, and based on the temperature difference between the two parts. The state of the power storage element may be determined.

(7) In the second embodiment, the battery 11 is cooled by blowing cold air on the battery 11 of the assembled battery 14, but the battery 11 is not limited to this, but the battery 11 is cooled by contacting the battery 11 with a Pelche element, a water-cooled jacket, or the like. You may use the device to do.

(8) In the first to fifth embodiments, the state of the power storage element is determined without counting the time by the timer, but the present invention is not limited to this, and the timer may be used in combination when determining the state of the power storage element. good. For example, when it is determined that the temperature difference between the two parts of the power storage device is the same as or slightly smaller than the criterion, the timer counts the time for a predetermined time in a limited manner, and the predetermined time has elapsed. Later, the state of the power storage element may be determined again based on the temperature difference between the two parts of the power storage device.

(9) The technique disclosed in the present specification executes a process of determining the state of the power storage element based on the temperature difference information of the temperatures of the two parts of the power storage device in the computer of the power storage device provided with the power storage element. It may be applied to the state determination program of the power storage device.
Further, the technique disclosed in the present specification may be applied to a computer-readable storage medium in which the above-mentioned state determination program is stored.

1: Vehicle 2: Engine (an example of an internal combustion engine)
10, 40, 50, 60: Power storage device 11, 71: Battery 11A: Battery 11B: Battery 11C: Battery 13: Reference temperature measuring unit (an example of the second temperature measuring unit)
14: Batteries 15: Temperature measuring part (an example of the first temperature measuring part)
16: Management device

Claims (11)

It is a power storage device equipped with a power storage element.
The first and second temperature measuring units that measure the temperature of the two parts of the power storage device, respectively,
A management device for determining the stable state of the power storage element based on the temperature difference of each temperature acquired from the first and second temperature measuring units is provided.
A plurality of the storage elements are integrated to form an assembled battery, and each of the first and second temperature measuring units measures the temperature of a different storage element among the assembled batteries.
The first temperature measuring unit measures the temperature of the power storage element that easily dissipates heat in the assembled battery, and measures the temperature.
The second temperature measuring unit measures the temperature of the power storage element of the assembled battery, which is difficult to dissipate heat.
The management device acquires the temperature only of the power storage element that easily dissipates heat by the first and second temperature measuring units and the power storage element that does not easily dissipate heat, and based on the temperature difference between the two acquired power storage elements, the management device obtains the temperature. A power storage device that determines the stable state of the power storage element . The power storage device according to claim 1 , wherein the first temperature measuring unit measures the temperature of the power storage element located at the end of the assembled battery, and the second temperature measuring unit is the assembled battery. A power storage device that measures the temperature of the power storage element located in the center. The power storage device according to claim 1 or 2 .
The management device is a power storage device that determines the stable state of the power storage element by using the temperature difference and a timer in combination. The power storage device according to any one of claims 1 to 3 .
The management device is a power storage device that determines the deterioration state or the life of the power storage element when the power storage element is in a stable state. The power storage device according to any one of claims 1 to 4 , which is mounted on a vehicle including an internal combustion engine started by cranking.
The management device is a power storage device that determines a stable state of the power storage element on condition that a signal for executing the cranking of the internal combustion engine is received. It is a method of determining the state of a power storage device equipped with a power storage element.
The temperature of each of the two different parts of the power storage device is measured, and the stable state of the power storage element is determined based on the temperature difference information of the temperatures of the two parts.
Of the plurality of integrated power storage elements, the temperature of only the power storage element that easily dissipates heat and the power storage element that does not easily dissipate heat are measured as two different parts of the power storage device, and the temperature is based on the temperature difference between the two measured power storage elements. , A method for determining a state of a power storage device, which determines a stable state of the power storage element . The method for determining the state of the power storage device according to claim 6 .
A method for determining the state of a power storage device, which determines the stable state of the power storage element by using the temperature difference and a timer in combination. The method for determining the state of the power storage device according to claim 6 or 7 .
A method for determining a state of a power storage device, which determines a deteriorated state or a life of the power storage element when the power storage element is in a stable state. It is a management device that manages power storage elements.
The stable state of the power storage element is determined based on the temperature difference of each temperature acquired from the first and second temperature measuring units that measure the temperatures of two different parts of the power storage device provided with the power storage element.
As two different parts of the power storage device, among the plurality of integrated power storage elements, only the power storage element that easily dissipates heat and the power storage element that does not easily dissipate heat are measured by the first and second temperature measuring units, and the temperature is measured by the first and second temperature measuring units. And a management device for determining the stable state of the power storage element based on the temperature difference between the two power storage elements acquired from the second temperature measuring unit. The management device according to claim 9 .
A management device that determines the stable state of the power storage element by using the temperature difference and a timer together. The management device according to claim 9 or 10.
A management device that determines the deterioration state or the life of the power storage element when the power storage element is in a stable state.

Images