JP2019061847A - Power storage device, management device, and method for determining state of power storage device - Google Patents

Abstract

To determine the state of a power storage element without relying on time count by a timer.SOLUTION: A power storage device 10 including batteries 11 includes: a temperature measurement part 15 and a reference temperature measurement part 13 which measure temperatures of two batteries 11B, 11A, respectively, in the power storage device 10; and a management device 16 to determine the state of the batteries 11 on the basis of a temperature difference ΔT between temperatures T1, T2 obtained from the temperature measurement part 15 and the reference temperature measurement part 13, respectively.SELECTED DRAWING: Figure 4

Description

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

  2. Description of the Related Art A vehicle such as a car is equipped with a power supply of on-vehicle electrical components and a power storage device used as a drive source of the vehicle. Generally, the power storage device includes a plurality of power storage elements, and the deterioration state or the like of these power storage elements can be estimated by measuring the internal resistance of the power storage element. 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 storage element is affected by the usage of the storage element. For example, when a large current flows, the temperature of the storage element rises, and the measured value of the internal resistance is also affected according to the temperature rise of the storage element. Immediately after the end of energization, it is known that the terminal voltage of the storage element deviates from the correct value due to the polarization phenomenon inside the storage element, and the deviation of the terminal voltage also becomes an error factor of the measured value of the internal resistance. This polarization phenomenon disappears with time and reaches a stable state unless a large current flows.

  Conventionally, when it is detected that the power storage device is in the non-current state, the timer counts the elapsed time by the timer from when the power storage device is in the non-current state, and when the predetermined time has elapsed There has been developed a technique for measuring the internal resistance, assuming that the state has reached a stable state, and estimating the state of the storage element based on the internal resistance (for example, Patent Document 1).

Unexamined-Japanese-Patent No. 2006-149070

  According to the above technology, whether or not the storage element has reached a stable state is based on the count of elapsed time regardless of the usage state of the storage element before the point in time when it is detected that the storage device has become a currentless state. Deciding. In the case where the storage element is energized for only a short time, although the storage element returns to the stable state in a short time, it is necessary to wait until a predetermined time has elapsed.

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

  The storage device has first and second temperature measuring units for measuring the temperatures of the two parts respectively, and the storage device is based on the temperature difference between the temperatures obtained from the first and second temperature measuring units. Determine the state of

  In this configuration, it is possible to determine that the state of the 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 the storage device An exploded perspective view of a power storage device Block diagram showing the electrical configuration of the storage device Flowchart showing a flow of processing for determining the stable state of the temperature of the storage element Block diagram showing the electrical configuration of the power storage device according to the second embodiment Block diagram showing the electrical configuration of the power storage device according to the third embodiment Block diagram showing the electrical configuration of the power storage device according to the fourth embodiment Partially cutaway side view showing the storage element according to Embodiment 5 Graph showing change with time of temperature of two different batteries among power storage devices

<Overview of Embodiment>
The power storage device disclosed in the present specification includes first and second temperature measurement units that respectively measure temperatures of two portions of the power storage device, and temperatures of the respective temperatures obtained from the first and second temperature measurement units. And a management device that determines the state of the storage element based on the temperature difference.

  When current flows to the storage element of the storage device, heat is generated inside the storage element to increase the internal temperature. When the current is interrupted, the heat generation is stopped, 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 different at 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 there is a large temperature difference depending on the location, the temperature difference eventually shrinks with the passage of time, and eventually the entire system reaches thermal equilibrium.

  FIG. 10 shows an example of the change with time of the temperature of two storage elements in different parts of the storage device when the storage device is stopped after being energized for a predetermined time and the storage device is left. A curve indicated by symbol P indicates a temperature change of the storage element in a portion of the storage device that is relatively difficult to dissipate heat. A curve indicated by a symbol Q indicates a temperature change of the storage element in a portion where heat release is relatively easy.

  When current is supplied to the power storage device, the temperature of the storage element in the portion where heat is not easily dissipated rises faster than the temperature of the storage element in the portion where the heat is likely to be dissipated. That is, a temperature difference occurs between the portion where it is difficult to release heat and the portion where it is easy to release heat. Thereafter, the amount of heat generated by energization and the amount of heat release balance each other, so that the temperature of each portion goes to equilibrium with the temperature difference left. When energization of the storage device is stopped (time indicated by symbol R), the temperature difference of each part gradually decreases while the temperature of each part gradually decreases due to thermal diffusion and heat dissipation to the outside, and finally the entire temperature Go to thermal equilibrium where

  The temperature is measured by the first and second temperature measuring units at two portions of the power storage device, and the storage element of the power storage device is based on the temperature difference between the first and second temperature measuring portions reaching a predetermined range. It is possible to determine the state of

  Even if the storage device that has not been used for a long time starts charging and discharging, the storage element of the storage device becomes stable while the temperature difference between the first and second temperature measuring parts remains within the predetermined range. It can be determined that there is. When the current flows in the storage element for a short time, and the temperature distribution in the storage device and the state in the storage element do not change significantly, the temperature difference in each temperature measuring unit does not increase, so the state is early and stable. Can determine that.

  At least one of the first and second temperature measurement units may be provided to measure the temperature of the storage element, and the other may measure the temperature of a portion of the storage device remote from the storage element. According to this configuration, when the temperature of the storage element is close to the temperature of the part away from here, that is, the environmental temperature of the storage element, the temperature difference between the two temperature measuring parts becomes smaller. The state of the storage element can be determined based on the above.

  According to this configuration, since the state of the storage element is determined based on the temperature difference between the two parts of the storage device, it is not necessary to have a timer for continuously counting the time since the storage device has no current. Can be Even when the control device of the power storage device needs 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 operated continuously is not used.

  A storage device is installed at a location that is unevenly affected by an irregular or storage device such as the storage device is installed at a location susceptible to the outside air temperature, or the vehicle engine is near the storage device. If is provided, it may be erroneously determined only by monitoring with a timer as in the prior art. For example, when the temperature condition of the location where the storage device is disposed changes irregularly due to the influence of the outside air temperature or the thermal effect of the engine, it is determined that the storage element has reached the stable state by the timer count. In some cases, the temperature of the storage element is still too high to reach a steady state. Also, even if one of the storage devices becomes hotter than the others due to the outside air temperature or the thermal effect of the engine, even if the storage element is considered to have reached a stable state by the timer count, It can not be said that the entire storage element is thermally stable.

  According to this configuration, since the state of the storage element is determined based on the temperature difference between the two parts of the storage device, an erroneous determination due to an external irregular thermal effect is less likely to occur.

  When the internal resistance of the storage element is estimated according to the determination that the state is stable, and the temperature of the storage element is further corrected, temperature correction based on the temperature with less variation can be performed. Accuracy can be improved. The details will be described below. Since the internal resistance of the storage element has temperature dependency, temperature correction is generally performed when the internal resistance of the storage element is estimated. If the temperatures of the plurality of storage elements do not stabilize and there is a variation in the temperature of each storage element, it is not known at which temperature the correction should be made, so the accuracy in estimating the internal resistance of the storage elements decreases There is a risk of According to this configuration, it can be determined whether or not the temperature of the storage element is stable, so that the accuracy of temperature correction of the internal resistance of the storage element can be improved, and the internal resistance of the storage element can be accurately determined. It can be estimated.

  In the above power storage device, when a plurality of the power storage elements are integrated to form a battery pack, the first and second temperature measuring units may measure temperatures of different power storage elements of the battery pack. it can.

  According to this configuration, since the state of the storage element can be determined based on the temperature deviation of each storage element in the entire assembled battery, in particular, the assembled battery is configured by integrating storage elements of the same type and the same capacity. When it is present, the state of the storage element can be determined more accurately. In this case, it is preferable that the first and second temperature measuring units be provided to the storage element located at the center of the assembled battery and the storage element located at the end of the assembled battery.

  The first and second temperature measuring units may be provided in different parts of the same storage element. Even with the same storage element, the deviation of the internal temperature and how the temperature changes with the passage of time is closely related to the stability of the storage element, so the temperature difference between different parts of the same storage element The state of the storage element can be determined based on

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

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

First Embodiment
The first embodiment will be described with reference to FIGS. 1 to 5. About several same members, a code | symbol may be attached | subjected only to one member and a code | symbol may be abbreviate | omitted about another member.
1. Description of Power Storage Device 10 As shown in FIG. 1, the vehicle 1 includes a power storage device 10. As shown in FIG. 2, the storage device 10 has a box-shaped battery case 31, and the battery case 31 contains a battery pack 14 and a control board 38, each of which includes a plurality of batteries 11 (storage elements). It is done. In the following description, referring to FIGS. 2 and 3, the vertical direction of the battery case 31 when the battery case 31 is placed horizontally without being inclined with respect to the installation surface is taken as the Y direction. 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 main body 33 opened upward, a positioning member 34 for positioning the plurality of batteries 11, an inner cover 35 mounted on the upper part of the case main body 33, and an upper cover 36. It is configured with. In the case main body 33, as shown in FIG. 3, a plurality of cell chambers 33A in which the respective batteries 11 are individually accommodated are provided side by side in the X direction.

  As shown in FIG. 3, the positioning members 34 have a plurality of bus bars 37 disposed on the upper surface, and the positioning members 34 are disposed on the top of the plurality of batteries 11 disposed in the case main body 33. The 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 plan view. A pair of terminal portions 32P and 32N to which a harness terminal (not shown) is 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, for example, a metal such as a lead alloy, 32P is a positive electrode side terminal portion, and 32N is a negative electrode side terminal portion.

  A housing 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 inner lid 35 is attached to the case main body 33, whereby the battery 11 and the control substrate 38 are connected. Further, the upper lid 36 is attached to the upper portion of the inner lid 35, and closes the upper surface of the accommodation portion 35A accommodating the control substrate 38.

  The electrical configuration of power storage device 10 will be described with reference to FIG. 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 battery assembly 14 is composed of a plurality (four in the present embodiment) of batteries 11 of the same capacity connected in series. The plurality of batteries 11 are arranged in parallel (in the direction indicated by 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 it is not limited to the above configuration.

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

  The reference temperature measurement unit 13 is attached to the outer surface of the battery 11A positioned at one end (upper end in FIG. 4) in the parallel direction among the plurality of batteries 11 constituting the battery assembly 14. Among the plurality of batteries 11 constituting the battery assembly 14, a temperature measuring portion is provided 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. The reference temperature measurement unit 13 and the temperature measurement unit 15 can use known temperature measurement members such as a thermistor and a thermocouple. In the present embodiment, a thermistor is used.

  When the number of batteries 11 is an odd number (2 n -1, n is a natural number), the central portion of the battery assembly 14 counts the n-th battery 11 from both ends of the battery assembly 14. No, when the number of batteries 11 is an even number (2 n, n is a natural number), the n-th battery 11 counted from one end of the battery pack 14 and the n-th counted from the other end It refers to at least one of the batteries 11. In the present embodiment, the number of the batteries 11 constituting the assembled battery 14 is four (even number), so in FIG. 4, the second battery 11 B counted from the lower end of the assembled battery 14 is in the center in the parallel direction. It is supposed to be located.

  Since the battery 11A to which the reference temperature measurement unit 13 is attached is located at the end of the battery assembly 14, heat is easily dissipated to the outside. For this reason, when electricity is supplied to the storage device 10, among the batteries 11 constituting the assembled battery 14, it is one of the smallest temperature changes (difference between the low-temperature side equilibrium temperature and the high-temperature side equilibrium temperature).

  Since the battery 11B to which the temperature measuring unit 15 is attached is located at the central portion of the assembled battery 14, the heat generated at the time of energization is hardly dissipated. For this reason, when electricity is supplied to power storage device 10, it is one of the largest among the batteries 11 constituting battery assembly 14 (the difference between the low-temperature side equilibrium temperature and the high-temperature side equilibrium temperature).

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

  The reference temperature measurement unit 13 and the temperature measurement unit 15 described above are electrically connected to the management device 16 by the signal line 20. The reference temperature, which is the temperature of the battery 11A measured by the reference temperature measurement unit 13, and the measured temperature, which is the temperature of the battery 11B measured by the temperature measurement 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, the memory 18 is a program for calculating the temperature difference between the reference temperature and the measurement temperature, and determining whether the temperature difference between the reference temperature and the measurement temperature is smaller than a predetermined reference value, The reference value of is stored.

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

  Power storage device 10 is connected to cell motor 25 and charging device 26 via power supply line 22 and ground line 23. The cell motor 25 and the charging device 26 are controlled by a 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 can communicate between the two.

  When the ignition switch 24 is turned on and the signal for performing the cranking is given to the vehicle ECU 27, the cellular motor 25 is energized by the signal from the vehicle ECU 27, and the cranking is started to start the engine 2 which is an internal combustion engine. Do.

  The charging device 26 charges the battery assembly 14. In the present embodiment, the charging device 26 includes a generator driven by the engine 2 of the vehicle. The charging device 26 may receive power supply from an external power supply disposed 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. Process of Determining State of Battery 11 FIG. 5 is a flowchart of a process of determining the state of the battery 11 by the management device 16. When the ignition switch 24 is turned on, the vehicle ECU 27 executes the process of FIG. 5 prior to driving the cell motor 25 in response to the signal.

  The CPU 17 acquires the reference temperature T2 from the reference temperature measurement unit 13 (S10), and acquires the measurement temperature T1 from the temperature measurement unit 15 (S20). The CPU 17 calculates a temperature difference .DELTA.T (= .vertline.T2-T1.vertline.) Between the measured temperature T1 and the reference temperature T2 and compares the temperature difference .DELTA.T with a reference value Tref previously stored in the memory 18 (S30).

  If the temperature difference ΔT is equal to or less than the reference value Tref, the CPU 17 determines that the battery 11 has reached a stable state without any temperature bias, sets a stable state flag (S40), and ends the process. If the reference value Tref is exceeded, the processing is ended without setting the same flag. Thereafter, the CPU 17 immediately executes cranking by the cell motor 25 to start the engine 2.

  When the steady state flag is set, the CPU 17 obtains the current flowing at the time of 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 steady state flag is set, and the temperature difference ΔT between the temperatures T1 and T2 of the battery 11 is relatively small (ΔT ≦ Tref). The internal resistance at the standard temperature is calculated by converting the calculated internal resistance into the internal resistance at a predetermined standard temperature (temperature correction) using the temperature T1 or T2 of (4). Since the internal resistance at this standard temperature reflects the deterioration state of the battery 11, etc., the CPU 17 determines the deterioration state of the battery 11 to the assembled battery 14 or adds the information of the internal resistance at that standard temperature or Make a decision.

  According to this configuration, since 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, the timer activated upon detection of the non-current state The state determination can be performed without measuring that a predetermined time has elapsed.

  Therefore, it is not necessary to start the timer continuously, and it is sufficient to acquire the temperatures T1 and T2 when necessary, so the system of the power storage device 10 may be turned off, or some event may occur. It is also possible to set a low power consumption state in which each temperature T1, T2 is acquired.

  In the present embodiment, the battery assembly 14 is configured by integrating a plurality of batteries 11, and the reference temperature measurement unit 13 measures the temperature of the battery 11A configuring the battery assembly 14, and the temperature measurement unit 15 measures the battery 11A. And the temperature of the battery 11B different from

  The thermal conditions of the batteries 11 arranged at different positions in the assembled battery 14 are different. For this reason, when the battery assembly 14 is energized, a temperature difference may occur between the different batteries 11. According to this configuration, since 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, in particular, the assembled battery 14 integrates the batteries 11 of the same capacity and the same capacity. When configured, the state of the battery 11 can be determined more accurately.

  In the present embodiment, the reference temperature measurement unit 13 measures the temperature of the battery 11A located at the end of the battery assembly 14, and the temperature measurement unit 15 measures the temperature of the battery 11B located in the center of the battery assembly. 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 battery 11B is energized to the power storage device 10, the battery 11B hardly has the highest temperature among the batteries 11 constituting the assembled battery 14. For this reason, the temperature difference between the battery 11A and the battery 11B is considered to be the largest among various temperature differences among the four batteries 11 constituting the assembled battery 14.

  Therefore, the state of the assembled battery 14 can be determined more accurately than 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 measurement temperature T1 of the battery 11B is less than or equal to the reference value Tref, the temperature deviation of the batteries 11 constituting the assembled battery 14 is small. It means that. Therefore, by using the reference temperature T2 of the battery 11A or the measurement 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 a threshold value of the temperature difference ΔT between the measurement temperature T1 and the reference temperature T2 is the number of the 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 performing an experiment in advance. As in the present embodiment, in the configuration in which the reference temperature measurement unit 13 is disposed at the end in the parallel direction in the assembled battery 14 and the temperature measurement unit 15 is disposed at the center position, 1 is set as the reference value Tref. C. or less is preferable, and 0.5 C or less is more preferable.

  The 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 the signal for executing the cranking of the engine 2 on condition that the battery 11 is used. Determine the status. Thereby, the management device 16 determines the state of the battery 11 immediately before cranking. If it is determined that the battery 11 is in a stable state immediately before cranking, it is preferable to estimate the internal resistance using the current flowing during cranking.

  At the time of cranking of engine 2, a relatively large current flows in power storage device 10, so the accuracy in calculating the internal resistance of battery 11 can be improved.

  If it is determined that the state of the battery 11 is stable, the internal resistance of the battery 11 can be accurately estimated even while the vehicle 1 is traveling.

<Modification>
Next, a modification of this 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 on-vehicle accessory devices such as the radio and the audio device are turned on. When the ignition switch 24 is set to the on position, the power of the ignition system of the engine 2 is turned on. When the ignition switch 24 is set to the start position, a signal for performing cranking is transmitted.

  When the ignition switch 24 is set to the accessory position or the on position, the vehicle ECU 27 instructs the CPU 17 of the management device 16 to execute processing for determining the state of the battery 11. The process of determining the state of the battery 11 and the subsequent processes are the same as those of the first embodiment described above, and thus the description thereof will not be repeated.

  As described above, the state of the battery 11 may be determined in a state where the occupant does not start the engine 2 and sets the ignition switch 24 to the accessory position or the on position and uses a radio, an audio device or the like.

Second Embodiment
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 battery assembly 14 along the direction indicated by the arrow B. The cold air may be branched 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 disposed at the top in FIG. 6 is most likely to be cooled by cold air. For this reason, when the power storage device 40 is energized, the change in temperature (the speed at which the temperature decreases) is the smallest among the batteries 11 constituting the assembled battery 14. A reference temperature measurement unit 13 is disposed on the outer surface of the battery 11A.

  Since the battery 11C disposed at the lowermost part in FIG. 6 is located on the most leeward side of the cold air, the cooling efficiency is the lowest. Therefore, when power storage device 40 is energized, the change in temperature (the rate at which the temperature decreases) is the largest among the batteries 11 constituting battery assembly 14. A temperature measuring unit 15 is disposed on the outer surface of the battery 11C.

  The configuration other than the above is substantially the same as that of the first embodiment, so the same reference numerals are given to the same members, and the overlapping 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 this embodiment, since the state of the battery 11 is determined based on the temperature difference between the battery 11A and the battery 11C, when it is detected that the temperature difference between the battery 11A and the battery 11C becomes less than a predetermined reference value This means that all temperature differences among the other batteries 11 constituting the battery assembly 14 are smaller than a predetermined reference value. Therefore, the state of each battery 11 can be accurately determined even if the reference value is relatively large in consideration of the detection error, the comparison error, and the like.

Embodiment 3
In the power storage device 50 according to the present embodiment, as shown in FIG. 7, the reference temperature measurement unit 13 is disposed in the management device 16. In detail, the management device 16 is provided inside the battery case 31 of the power storage device 50, and the reference temperature measurement unit 13 is disposed on the control board 38 that constitutes the management device 16. The CPU 17 acquires the temperature T2 inside the management device 16 measured by the reference temperature measurement unit 13 as a reference temperature.

  The configuration other than the above is substantially the same as that of the first embodiment, so the same reference numerals are given to the same members, and the overlapping description will be omitted.

  When management device 16 is provided inside battery case 31 of power storage device 50, the temperature environment of management device 16 is substantially the same as the temperature environment of assembled battery 14. Even if the temperature of the battery assembly 14 rises due to charge and discharge, if the charge and discharge are completed and the temperature of the battery assembly 14 decreases, the temperature approaches 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 battery 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 the reference temperature measurement unit 13 and the reference temperature measurement unit 13 decreases, it is determined that the battery assembly 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 environmental temperature outside the power storage device 50 is high, the internal temperature of the assembled battery 14 and the management device 16 also becomes high, and the temperature difference ΔT between the two temperature measurement units 13 and 15 is affected by the environmental temperature Since it becomes a value which excluded, it is possible to improve the accuracy of the state determination of the battery 11.

Fourth Embodiment
The fourth embodiment will be described with reference to FIG. A 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 the power from the power storage device 60. The engine 2 and the cell motor 25 are not mounted on the vehicle 1. A power switch 61 is disposed in place of the ignition switch 24. Charging device 26 receives supply of power from an external power supply provided outside vehicle 1 to charge power storage device 60.

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

  The configuration other than the above is substantially the same as that of the first embodiment, so the same reference numerals are given to the same members, and the overlapping 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 acquires 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. Thereafter, 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>
In the fourth embodiment, 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, the power storage device 60 is charged immediately before being charged. The state of the battery 11 is determined.

  When an external power supply is connected to charging device 26, vehicle ECU 27 determines that charging of power storage device 60 is possible, and performs processing of determining the state of battery 11 of power storage device 60 to management device 16 Order to do. Thus, as in the fourth embodiment, the temperatures T1 and T2 are acquired, the temperature difference ΔT is calculated, and ΔT is compared with the reference value Tref previously stored in the memory 18. When the temperature difference ΔT is equal to or less than the reference value Tref, the stable state flag is set and the processing is ended. When the temperature difference ΔT exceeds the reference value Tref, the processing is ended without setting the same flag. Thereafter, the CPU 17 causes the charging device 26 to charge the power storage device 60.

  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 this charging, the internal resistance can be estimated using the current flowing at the time of charging. At the time of charging of power storage device 60, a relatively large current flows in power storage device 60, so that the accuracy in estimating the internal resistance of battery 11 can be improved.

Fifth Embodiment
The fifth embodiment will be described with reference to FIG. In the battery 71 of the present embodiment, the storage element 74 is accommodated inside the case 72. The reference temperature measurement unit 73 is attached to the outer surface of the upper wall of the case 72 of the battery 71 to measure 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 disposed slightly above the lower wall of the case 72. The temperature measuring unit 75 can be disposed at an arbitrary 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 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 disposed inside the case 72.

  Even with one battery 71, the calorific value and heat dissipation are different for each part, so that immediately after energization, the internal temperature may be uneven or a temperature difference may be generated between the internal temperature and the external temperature. The temperature difference between the inside and the outside and the temperature difference between the inside and the outside reduces with the passage of time after the end of energization, and finally reaches the thermal equilibrium.

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

Other Embodiments
The art disclosed herein is not limited to the embodiments described above with reference to the drawings. For example, the following embodiments are also included in the scope of the technology 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 a plurality of power storage elements constituting one power storage device. The present invention is not limited to this, and among the plurality of storage elements constituting one storage device, three or more storage elements each having a temperature measuring portion arranged in each of three or more different storage elements, and in which a temperature measuring portion is arranged The state of the storage element may be determined based on the temperature difference between two storage elements selected from among the above. Based on the temperature difference between the two storage elements, as shown in the above embodiment, it is not limited to determining the magnitude relationship between the temperature difference ΔT and the reference value Tref. For example, mathematical processing is added to the temperature difference ΔT Calculating and determining based on the calculated value.

(2) The first and second temperature measuring units may be NTC thermistors, PTC thermistors, thermocouples or the like, or may be non-contact type temperature sensors.

(3) The energy storage device according to the first to fifth embodiments is a rectangular shape, but is not limited to this, and may be a cylindrical shape or a bag shape formed by bonding a laminate film.

(4) The power storage devices 10, 40, and 60 according to the first to third embodiments are mounted on the vehicle 1 using the engine 2 as a power source, and the power storage device 50 according to the fourth embodiment uses a motor as a power source. The technology disclosed in the present specification is not limited to this, and the technology disclosed in the present specification is a vehicle (for example, HEV) using an engine and a motor as a power source, or a forklift, a power tool, a smartphone The present invention can be applied to a system that requires the determination of the stable state of a battery, such as an apparatus using a battery, such as PC, etc.

(5) Although the power storage device according to the first to fifth embodiments includes four power storage elements, the present invention is not limited to this. One power storage device may be configured to include one power storage element. In addition, two to three or five or more storage elements may be provided.

(6) Among the storage devices, the temperature of two parts where temperature changes due to charge and discharge of storage elements, such as terminals to which harness terminals are connected, control boards, bus bars, etc. are measured. The state of the storage element may be determined.

(7) In the second embodiment, the battery 11 is cooled by blowing cold air onto the battery 11 of the battery assembly 14. However, the present invention is not limited thereto. The battery 11 is cooled by contacting the battery 11 with a Peltier element, a water cooling jacket, or the like. Devices may be used.

(8) In the first to fifth embodiments, the timer is used to determine the state of the storage element without counting time by the timer, but the present invention is not limited to this. Even when the state of the storage element is determined, the timer may be used in combination. Good. For example, if 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 determination reference, the timer counts the time limited by the timer for a predetermined time, and the predetermined time has elapsed. The state of the storage element may be determined again based on the temperature difference between the two parts of the storage device later.

(9) The technology disclosed in the present specification executes processing for determining the state of the storage element based on temperature difference information of the temperature of the two parts of the storage device in a computer included in the storage device provided with the storage element You may apply to the state determination program of the electrical storage apparatus to make it
In addition, the technology disclosed in the present specification may be applied to a computer readable storage medium storing the state determination program described above.

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 measurement unit (an example of a second temperature measurement unit)
14: Battery assembly 15: Temperature measuring unit (an example of a first temperature measuring unit)
16: Management device

Claims (7)

A storage device comprising a storage element, wherein
First and second temperature measuring units that respectively measure temperatures of two parts of the power storage device;
A storage device comprising: a management device that determines the state of the storage element based on a temperature difference between temperatures obtained from the first and second temperature measuring units.   The power storage device according to claim 1, wherein a plurality of the power storage elements are integrated to constitute a battery pack, and the first and second temperature measuring units are different power storage elements of the battery pack. Power storage device that measures temperature.   The power storage device according to claim 2, wherein the first temperature measurement unit measures the temperature of the storage element located at the end of the assembled battery, and the second temperature measurement unit is of the assembled battery. A power storage device for measuring the temperature of the power storage element located in the center.   The power storage device according to claim 1, wherein the first and second temperature measuring units measure temperatures of different portions of the same power storage element. The power storage device according to any one of claims 1 to 4, being mounted on a vehicle including an internal combustion engine started by cranking,
The storage device determines the stable state of the storage element on the condition that the management device receives a signal for performing the cranking of the internal combustion engine. A method of determining the state of a storage device provided with a storage element, comprising:
A method of determining a state of a storage device, which measures temperatures of two different parts of the storage device and determines the state of the storage element based on temperature difference information of the temperatures of the two parts. A management device that manages storage elements, and
The management apparatus which determines the state of the said electrical storage element based on the temperature difference of each temperature acquired from the 1st and 2nd temperature-measurement part which each measures the temperature of two site | parts of the electrical storage apparatus provided with the said electrical storage element.

Images