JP2016031876A - Battery cooling state determination device, electric vehicle and battery cooling state determination method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a battery internal state estimation device capable of highly accurately and simply determining whether a battery is properly cooled while suppressing an operation load from increasing; and the like.SOLUTION: When it has been determined that an abnormality occurs in a battery (11) (S4 is No), it is determined whether the abnormality has been caused due to a failure of a cooling device (30) by adjusting a cooling amount in a cooling device (30) cooling the battery (S6) and comparing an actual temperature distribution Sexp3 inside the battery which is detected after the battery has been cooled at an adjusted cooling amount for a predetermined time with an actual temperature distribution Sexp2 that has been detected before cooling amount adjustment.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a battery cooling state determination device, an electric vehicle, and a battery cooling state determination method.

  In order to improve the efficiency of an engine vehicle equipped with an engine as a conventional driving power source, a hybrid electric vehicle equipped with a motor as a driving power source in addition to the engine, or an electric vehicle equipped with a motor instead of the engine Etc. (hereinafter may be collectively referred to as electric vehicles).

  In such an electric vehicle, a battery made of, for example, a secondary battery is mounted as a motor power source. For example, in the case of a battery such as a nickel metal hydride battery or a lithium ion battery of about 200 to 300 V, it is mounted on the vehicle as a battery pack made up of several hundred cells of about 1 to 4 V. Such a battery pack is discharged or charged by a chemical reaction, and this chemical reaction is accompanied by heat generation. Therefore, it is necessary to cool the battery pack with water or air. In order to maintain an appropriate operating state in such a battery pack, a technique for detecting a temperature distribution in the battery pack and controlling the refrigerant based on the temperature distribution has been proposed (see Patent Document 1).

Japanese Patent Application No. 9-272380 International Publication No. 2011/118080

  However, if only the temperature distribution in the battery pack is detected, abnormal temperature distribution caused by the cooling device, such as cooling fan failure or refrigerant circulation abnormality due to foreign matter mixing into ducts, etc., or cell deterioration or It is difficult to determine whether the temperature distribution is abnormal due to the battery side, such as a cell failure.

  Therefore, as a reference for monitoring the battery status, an electrical equivalent circuit is created by replacing the main components of the battery with parameters such as resistance and inductance, and an appropriate temperature distribution is estimated based on this equivalent circuit. (See Patent Document 2).

  However, the resistance and inductance of the equivalent circuit change not only with the SOC (State Of Charge) of the battery but also with the temperature of each cell constituting the battery. Further, many cells in the battery pack are cooled by water or air, but due to the structure, all the cells are not evenly cooled, and there is always a temperature difference between the battery packs. In Patent Document 2, the cell temperature is reflected in the equivalent circuit by sequentially matching each parameter of the equivalent circuit based on the comparison result with the actual measurement value, but the variation in the cell temperature inherently generated in the battery pack is reflected. As a result, it is difficult to calculate a reference value of an appropriate internal temperature distribution according to the internal state of the battery.

  In addition, as described above, a large number of cells are mounted in the battery pack, and if equivalent circuits are generated corresponding to all the cells, the calculation load increases due to calculation processing in those equivalent circuits. However, there is a problem that a high computing capacity and a large-capacity memory are required.

  The present invention has been made to solve such problems, and the object of the present invention is to highly accurately and easily determine whether or not the battery is appropriately cooled while suppressing an increase in calculation load. It is in providing the battery cooling state determination apparatus etc. which can be determined to this.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following aspects or application examples.

  (1) The battery cooling state determination device according to this application example has an equivalent circuit model that preliminarily holds an equivalent circuit model that expresses a temperature distribution expressed by a plurality of cells constituting a battery by an equivalent circuit smaller than the number of cells. A circuit model holding means, a cooling means for cooling the battery, a battery temperature distribution estimating means for estimating a temperature distribution inside the battery when the battery used for a predetermined period of time is normally deteriorated based on the equivalent circuit model, Battery temperature distribution detecting means for detecting temperature of the plurality of cells and detecting temperature distribution inside the battery used for the predetermined period; temperature distribution estimated by the battery temperature distribution estimating means; and battery temperature distribution The temperature distribution detected by the detection means is compared, and the battery is determined from the deterioration state of the battery after the predetermined period has elapsed. When the battery abnormality determining means for determining abnormality and the battery abnormality determining means determine that the battery is abnormal, the cooling amount by the cooling means is adjusted, and after cooling for a predetermined time with the adjusted cooling amount, By comparing the temperature distribution inside the battery detected by the battery temperature distribution detection means with the temperature distribution inside the battery detected by the battery temperature distribution detection means before adjusting the cooling amount, the abnormality of the cooling means Cooling abnormality determining means for determining whether or not.

  (2) Moreover, the electric vehicle which concerns on this application example contains the battery cooling state determination apparatus of said (1).

  (3) In addition, the battery cooling state determination method according to this application example has in advance an equivalent circuit model that expresses a temperature distribution expressed by a plurality of cells constituting the battery by an equivalent circuit smaller than the number of cells. A first step of estimating a temperature distribution inside the battery when the battery used for a predetermined period of time has deteriorated normally based on the equivalent circuit model, and detecting temperatures of the plurality of cells, The third step of detecting the temperature distribution inside the battery that has been used for the predetermined period, the temperature distribution estimated by the second step, and the temperature distribution detected by the third step are compared, and the predetermined period A fourth step of determining an abnormality of the battery from the deterioration state of the battery after the lapse of time, and a determination that the battery is abnormal by the fourth step. In this case, the amount of cooling by the cooling means for cooling the battery is adjusted, the temperature distribution inside the battery detected after cooling for the predetermined time with the adjusted amount of cooling, and the inside of the battery detected before adjusting the cooling amount And a fifth step of determining whether or not the cooling means is abnormal by comparing with the temperature distribution.

  According to the present invention, it is possible to easily and accurately determine whether or not the battery is appropriately cooled while suppressing an increase in calculation load.

1 is an overall configuration diagram showing a hybrid truck on which a battery cooling state determination device of an embodiment is mounted. It is explanatory drawing which shows the equivalent circuit model which modeled (a) temperature distribution of all the cells of a battery, and (b) temperature distribution. It is a schematic diagram which shows an example of an equivalent circuit. It is a flowchart which shows the cooling state determination control routine of the battery which vehicle ECU in this embodiment performs. It is explanatory drawing (a) about the shift of measured temperature distribution (b).

  Hereinafter, an embodiment in which the present invention is embodied in a battery cooling state determination device, an electric vehicle, and a battery cooling state determination method will be described.

  FIG. 1 is an overall configuration diagram showing a hybrid truck equipped with a battery cooling state determination device of the present embodiment.

  The hybrid truck 1 is configured as a so-called parallel hybrid vehicle, and may be referred to as a vehicle in the following description. A vehicle 1 is equipped with a diesel engine (hereinafter referred to as an engine) 2 as a driving power source and a motor 3 that can also operate as a generator such as a permanent magnet synchronous motor. A clutch 4 is connected to the output shaft of the engine 2, and an input side of the automatic transmission 5 is connected to the clutch 4 via a rotating shaft of the motor 3. A differential device 7 is connected to the output side of the automatic transmission 5 via a propeller shaft 6, and left and right drive wheels 9 are connected to the differential device 7 via a drive shaft 8.

  The automatic transmission 5 automates the connection / disconnection operation of the clutch 4 and the switching operation of the shift stage based on a general manual transmission. In this embodiment, the automatic transmission 5 has a shift stage of 12 forward speeds and 1 reverse speed. ing. Of course, the configuration of the automatic transmission 5 is not limited to this, and can be arbitrarily changed. For example, the automatic transmission 5 may be embodied as a manual transmission, or a so-called dual clutch type automatic transmission having two power transmission systems. It may be embodied as a transmission.

  A battery 11 is connected to the motor 3 via an inverter 10. The DC power stored in the battery 11 is converted into AC power by the inverter 10 and supplied to the motor 3 (power running control), and the driving force generated by the motor 3 is transmitted to the drive wheels 9 after being shifted by the automatic transmission 5. The vehicle 1 is made to travel. For example, when the vehicle 1 decelerates or travels on a downhill road, the motor 3 operates as a generator by reverse driving from the drive wheel 9 side (regenerative control). The negative driving force generated by the motor 3 is transmitted to the driving wheel 9 side as a braking force, and the AC power generated by the motor 3 is converted into DC power by the inverter 10 and charged to the battery 11.

  The driving force generated by the motor 3 is transmitted to the driving wheel 9 regardless of the state of connection / disconnection of the clutch 4, and the driving force generated by the engine 2 is driven only when the clutch 4 is connected. 9 side. Therefore, when the clutch 4 is disengaged, the positive or negative driving force generated by the motor 3 as described above is transmitted to the driving wheel 9 side, and the vehicle 1 travels. When the clutch 4 is connected, the driving force of the engine 2 and the motor 3 is transmitted to the driving wheel 9 side, or only the driving force of the engine 2 is transmitted to the driving wheel 9 side, and the vehicle 1 travels.

  The vehicle ECU 20 is a control circuit for integrated control of the entire vehicle. For this purpose, the vehicle ECU 20 includes an accelerator sensor 21 for detecting the operation amount θacc of the accelerator pedal 12, a brake switch 22 for detecting the depression operation of the brake pedal 13, a vehicle speed sensor 23 for detecting the speed (vehicle speed) V of the vehicle 1, an engine. Various sensors and switches such as an engine rotational speed sensor 24 for detecting the rotational speed Ne of the motor 2 and a motor rotational speed sensor 25 for detecting the rotational speed Nm of the motor 3 are connected.

  Although not shown, the vehicle ECU 20 is connected to an actuator for connecting / disconnecting the clutch 4, an actuator for operating the automatic transmission 5, etc., and an engine ECU 26 for engine control and an inverter ECU 27 for inverter control. And a battery ECU 28 for managing the battery 11 are connected.

  The vehicle ECU 20 calculates a required torque required to cause the vehicle 1 to travel based on the accelerator operation amount θacc by the driver, and selects the travel mode of the vehicle 1 based on the required torque, the SOC of the battery 11, and the like. In this embodiment, an E / G mode that uses only the driving force of the engine 2, an EV mode that uses only the driving force of the motor 3, and an HEV mode that uses both the driving force of the engine 2 and the motor 3 are set as the traveling mode. The vehicle ECU 20 selects one of the travel modes.

  The vehicle ECU 20 converts the required torque into a torque command value that the engine 2 and the motor 3 should output based on the selected travel mode. For example, in the HEV mode, the required torque is distributed to the engine 2 side and the motor 3 side, and torque command values for the engine 2 and the motor 3 are calculated based on the gear position at that time. In the E / G mode, the required torque is converted into a torque command value for the engine 2 based on the gear position, and in the EV mode, the required torque is converted into a torque command value for the motor 3 based on the gear speed.

  Then, the vehicle ECU 20 disconnects the clutch 4 in the EV mode and connects the clutch 4 in the E / G mode and HEV mode in order to execute the selected travel mode, and then sends a torque command value to the engine ECU 26 and the inverter ECU 27. Output as appropriate. While the vehicle 1 is traveling, the vehicle ECU 20 calculates a target shift stage from a shift map (not shown) based on the accelerator operation amount θacc, the vehicle speed V, and the like, and the actuator 4 connects and disconnects the clutch 4 to achieve this target shift stage. Executes operation and gear change operation.

  On the other hand, the engine ECU 26 performs injection amount control and injection timing control so as to achieve the travel mode and the torque command value input from the vehicle ECU 20. For example, in the E / G mode and the HEV mode, the driving force is generated in the engine 2 with respect to the positive torque command value, and the engine brake is generated with respect to the negative torque command value. In the EV mode, the engine 2 is brought into a stopped holding state or an idle operation state by stopping fuel injection.

  Further, the inverter ECU 27 controls the motor 3 via the inverter 10 so as to achieve the travel mode and the torque command value input from the vehicle ECU 20. For example, in the EV mode or HEV mode, the motor 3 is controlled by powering the positive torque command value to generate a positive driving force, and the motor 3 is regeneratively controlled to the negative torque command value. Generate negative driving force. In the E / G mode, the driving force of the motor 3 is controlled to zero. Further, the battery ECU 28 detects the temperature of the battery 11, the voltage of the battery 11, the current flowing between the inverter 10 and the battery 11, etc., and sequentially calculates the SOC of the battery 11 from these detection results and outputs it to the vehicle ECU 20. To do.

  Further, the battery 11 is configured by incorporating a plurality of cells in a battery pack, and a cooling device 30 (cooling means) for cooling each of these cells is provided. The cooling device 30 has a configuration in which, for example, a cooling circuit is disposed between each cell in the battery pack, and a cooling medium such as gas or water circulates in the cooling circuit. Then, the cells are cooled by heat exchange between the cooling medium and each cell, and consequently, the battery 11 is cooled. The configuration of the cooling device 30 is not limited to this, and each cell may be air-cooled by providing a fan in the battery pack and introducing air into the battery pack.

  The battery 11 is provided with a battery temperature sensor 31. The battery temperature sensor 31 is provided for each cell, and detects the actually measured temperature of each cell. The cooling device 30 and the battery temperature sensor 31 are electrically connected to the vehicle ECU 20.

  Here, the vehicle ECU 20 determines the cooling state of the battery 11. Specifically, an electrical equivalent circuit that simulates the internal state of the battery 11 is generated, and an abnormality of the battery 11 is detected based on the equivalent circuit. If the battery 11 is abnormal, the cooling amount of the cooling device 30 is adjusted, and it is determined whether or not there is an abnormality caused by the cooling device 30 from the change in the adjusted temperature distribution.

  The vehicle ECU 20 of the present embodiment simplifies the calculation process of the estimated value based on the equivalent circuit by modeling the temperature distribution of each cell constituting the battery 11.

  2A is an explanatory diagram showing the temperature distribution of all the cells of the battery 11, and FIG. 2B is an explanatory diagram of an equivalent circuit model composed of a plurality of equivalent circuits modeling the temperature distribution. As shown in FIG. 2 (a), a large number of cells 11a constituting the battery 11 are distributed in a temperature distribution according to the cooling state by the cooling medium (water, air, etc.) in the battery pack. Thus, there are a number of equivalent circuits corresponding to the number of cells. Such an actual temperature distribution of all the cells 11a is regarded as a standard deviation, and the same standard deviation is modeled so as to be expressed by a smaller number of cells (number of cells 11b = number of equivalent circuits) (FIG. 2). b). As shown in FIGS. 2A and 2B, the number of cells 11b is smaller than the number of all cells 11a.

  In this example, the number of cells is set to 10, and the temperature range is divided into five, and the cells 11a are grouped for each temperature range. As a result, four grouped cells 11b belong to the central temperature range corresponding to the average value, two cells 11b belong to each of the temperature ranges on both sides thereof, and one each to the temperature range on both sides. Cell 11b belongs. In the present embodiment, the equivalent circuit model is generated using the standard deviation as an index. However, the present invention is not limited to this as long as it is an index representing the temperature distribution of each cell 11a, and may be arbitrarily changed to another index.

  Since the behavior with respect to the temperature change of each cell 11a belonging to each temperature range is common, a total of five equivalent circuits are generated corresponding to each temperature range. In this embodiment, the temperature distribution of all the cells 11a of the battery 11 is specified by a prior test, an equivalent circuit model is generated in advance from the temperature distribution and stored in the battery ECU 28, and the battery ECU 28 is based on the equivalent circuit model. An estimation process is performed (equivalent circuit model holding means, first step).

  FIG. 3 is a schematic diagram showing an example of an equivalent circuit when the element of the steady internal resistance of the battery 11 is replaced with Rs, the element of the transient internal resistance is replaced with R1, C1, and the load is set to zero. The voltage element corresponding to the open circuit is replaced with Vocv. It is assumed that these parameters Rs, R1, C1, and Vocv change according to the SOC of the battery 11 and the cell temperature T, and each parameter is set as a function of the SOC and the cell temperature T. A voltage V1 between terminals of the cell 11a (hereinafter simply referred to as a cell voltage) is sequentially estimated from the circuit.

  The contribution of the cell voltage V1 estimated from the equivalent circuit in each temperature range with respect to the terminal voltage of the entire battery 11 (hereinafter simply referred to as the battery voltage) differs depending on the number of cells belonging to that temperature range. For this reason, the battery voltage is calculated from the cell voltage V1 of each equivalent circuit based on the weighting according to the number of cells.

  In this embodiment, the battery ECU 28 estimates the temperature distribution inside the battery 11 when the battery 11 that has been used for a predetermined period of time has deteriorated normally based on an equivalent circuit model (battery temperature distribution estimation means). Moreover, vehicle ECU20 detects the temperature distribution inside the battery 11 used for the predetermined period from the measured temperature of each cell 11a detected by the battery temperature sensor 31 (battery temperature distribution detection means). Further, the vehicle ECU 20 compares the estimated temperature distribution with the actually measured temperature distribution, and determines the abnormality of the battery 11 from the deterioration state of the battery 11 after a predetermined period has elapsed (battery abnormality determination means).

  If there is an abnormality in the battery 11, the cooling amount of the cooling device 30 is first adjusted in order to identify whether the cooling device 30 is abnormal. Whether or not the cooling device 30 is abnormal by detecting a temperature distribution based on the measured temperature of each cell 11a after cooling with the adjusted cooling amount for a predetermined time and comparing it with the measured temperature distribution detected before adjusting the cooling amount. (Cooling abnormality determination means).

  Specifically, FIG. 4 is a flowchart showing a cooling state determination control routine for the battery 11 executed by the vehicle ECU 20, and will be described below with reference to the flowchart.

  The vehicle ECU 20 starts the cooling state determination control routine shown in FIG. First, in step S1, the vehicle ECU 20 determines whether or not a predetermined time has elapsed since the start. This fixed time is set to a time until the temperature distribution of each cell 11a of the battery 11 is stabilized, for example. If the predetermined time has not elapsed, for example, if the cell temperature of the battery 11 is not stable immediately after key-on or the like, the determination result is false (No), and the determination in step S1 is repeated. On the other hand, if the predetermined time has elapsed, the determination result is true (Yes), and the process proceeds to the next step S2.

  In step S <b> 2, the vehicle ECU 20 detects the temperature distribution Sexp <b> 1 from the measured temperature of each cell 11 a detected by the battery temperature sensor 31. That is, the vehicle ECU 20 detects the temperature distribution Sexp1 according to the actually measured values as shown in FIG.

  Subsequently, in step S3, the battery ECU 28 calculates the modeled temperature distribution Scalc1 modeled as shown in FIG. 2B using the temperature distribution Sexp1 based on the measured temperature as an initial condition, and the modeled temperature distribution Scalc1 is calculated. A modeled temperature distribution Scalc2 predicted after energization for a predetermined period from the distribution Scalc1 is calculated (second step). The battery ECU 28 stores a deterioration tendency according to the temperature distribution of each cell 11b modeled by a prior test as a database, and the modeled temperature distribution Scalc2 after a predetermined period from the current modeled temperature distribution Scalc1 based on the database. Is calculated. In this way, by predicting the modeled temperature distribution Scalc2 after a predetermined period based on the modeled temperature distribution Scalc1, the load of the calculation processing related to the prediction is reduced.

  In step S4, the vehicle ECU 20 calculates the measured temperature distribution Sexp2 again after a predetermined period has elapsed after calculating the measured temperature distribution Sexp1 in step S2 (third step), and the measured temperature distribution Sexp2 is calculated in step S3. It is determined whether or not the predicted modeled temperature distribution Scalc2 is substantially the same (fourth step). Specifically, for example, it is determined whether or not the standard deviation σexp2 of the measured temperature distribution Sexp2 is within a predetermined range with respect to the standard deviation σcalc2 of the modeled temperature distribution Scalc2. The standard deviation σ to be compared is one or both of + σ and −σ.

  If the determination result is true (Yes), that is, if the measured temperature distribution Sexp2 is almost the same as the predicted modeled temperature distribution Scalc2, and the battery 11 can be determined to be normal, the process proceeds to the next step S5.

  In step S5, since there is no abnormality in the deterioration state of the battery 11, the vehicle ECU 20 determines that the cooling device 30 is also normal, and returns the routine.

  On the other hand, if the determination result in step S4 is false (No), that is, if the measured temperature distribution Sexp2 is far from the predicted modeled temperature distribution Scalc2 and it can be determined that the battery 11 is abnormal, the process proceeds to step S6. Specifically, for example, if σexp2 of the measured temperature distribution Sexp2 is outside a predetermined range with respect to the standard deviation σcalc2 of the modeled temperature distribution Scalc2, the process proceeds to step S6.

  In step S <b> 6, the vehicle ECU 20 adjusts the cooling device 30 so that the cooling amount is higher than that normally required for the battery 11. Note that the cooling amount may be adjusted to be lower than that normally required.

  In subsequent step S7, the vehicle ECU 20 detects the measured temperature distribution Sexp3 again after adjusting the cooling amount and cooling for a predetermined time, and compares the measured temperature distribution with the measured temperature distribution Sexp2 in step S4. As a result of this comparison, it is determined whether or not the temperature distribution is shifted in accordance with the adjustment of the cooling amount in step S6 (fifth step).

  Here, referring to the explanatory diagram of the shift of the actually measured temperature distribution in FIG. 5, as shown in FIG. 5A, the actually measured temperature distribution Sexp3 after the cooling amount adjustment is compared with the actually measured temperature distribution Sexp2 before the cooling adjustment. However, if only the temperature region changes according to the cooling amount while forming the same temperature distribution shape, it can be determined that each cell 11a is uniformly cooled. Therefore, in this case, the determination result in step S7 is true (Yes), the process proceeds to step S5 described above, and it is determined that at least the cooling device 30 is normal and the abnormality of the battery 11 is due to another cause.

  On the other hand, as shown in FIG. 5B, when the temperature distribution shape of the measured temperature distribution Sexp3 after adjusting the cooling amount is changed with respect to the measured temperature distribution Sexp2 before adjusting the cooling, It can be determined that an abnormality has occurred in the cooling device 30 such that a part of the cell 11a is not cooled or is biased. Therefore, in this case, the determination result in step S7 is false (No), and the process proceeds to step S8.

  In step S <b> 8, the vehicle ECU 20 determines that the abnormality of the battery 11 is caused by the cooling device 30 and that the cooling device 30 may be broken, and returns the routine.

  When the vehicle ECU 20 determines that there is a possibility of failure in the cooling device 30, for example, a warning is given to the driver by a warning light or alarm device (not shown), or a notification is given to a management center that manages the vehicle. Is preferably performed. By doing so, unnecessary battery deterioration due to a high temperature state can be prevented in advance, the cost for cell replacement can be suppressed, and the economic efficiency can be improved.

  As described above, the vehicle ECU 20 first calculates the modeled temperature distribution Scalc1 from the measured temperature distribution Sexp1 in step S3, predicts the modeled temperature distribution Scalc2 after a predetermined period based on the modeled temperature distribution Scalc1, and this model. The cooling state determination is performed using the conversion temperature distribution Scalc2. Thus, using an equivalent circuit model that expresses the temperature distribution inside the battery 11 with an equivalent circuit that is smaller than the actual number of cells, the temperature distribution Scalc2 inside the battery 11 when the battery 11 that has been used for a predetermined period of time has deteriorated normally. Is estimated. As a result, it is possible to estimate the temperature distribution in a normal deterioration state in which the variation in temperature unique to each cell is reflected, while suppressing an increase in calculation load. By comparing the estimated temperature distribution Scalc2 and the temperature distribution Sexp2 based on the actually measured values, it is possible to determine with high accuracy whether or not the cooling of the battery 11 is normal.

  As described above, first, it is determined whether an abnormality has occurred in the battery 11 using the temperature distribution estimated with a small calculation load. If any abnormality occurs in the battery 11, the cooling amount is adjusted, and the abnormality in the battery 11 is caused by the cooling device 30 depending on whether or not the measured temperature distribution changes according to the cooling amount. Or other causes can be determined.

  As described above, according to the battery cooling state determination device and the like according to the present embodiment, it is possible to easily and accurately determine whether or not the battery 11 is appropriately cooled while suppressing an increase in calculation load. it can.

  As described above, in the present embodiment, an equivalent circuit model is generated from the temperature distribution of all the cells 11a of the battery 11 and stored in the battery ECU 28 in advance by a preliminary test. However, the present invention is not limited to this. For example, the vehicle ECU 20 may have the function of the battery ECU 28.

  When the equivalent circuit model is generated and stored in advance as in the above embodiment, the coefficient used for the equivalent circuit model may be switched according to different cooling conditions in the battery pack. In this case, a plurality of coefficient maps corresponding to the cooling conditions may be stored in advance, and a coefficient corresponding to the cooling condition at that time may be selected and applied to the estimation process.

  This is the end of the description of the embodiment, but the aspect of the present invention is not limited to this embodiment. For example, in the above embodiment, the battery cooling state determination device for a hybrid truck is embodied, but it may be a battery cooling state determination device for an electric vehicle equipped with only a motor as a driving power source.

11 battery 11a, 11b cell 20 vehicle ECU (battery temperature distribution detecting means, battery abnormality determining means, cooling abnormality determining means)
28 battery ECU (equivalent circuit model holding means, battery temperature distribution estimating means)
30 Cooling device (cooling means)
31 Battery temperature sensor

Claims (3)

An equivalent circuit model holding means for holding in advance an equivalent circuit model for expressing a temperature distribution expressed by a plurality of cells constituting the battery by an equivalent circuit smaller than the number of cells;
A cooling means for cooling the battery;
Battery temperature distribution estimating means for estimating a temperature distribution inside the battery when the battery used for a predetermined period of time has deteriorated normally based on the equivalent circuit model;
Battery temperature distribution detecting means for detecting the temperature of the plurality of cells and detecting the temperature distribution inside the battery used for the predetermined period;
The temperature distribution estimated by the battery temperature distribution estimating means is compared with the temperature distribution detected by the battery temperature distribution detecting means, and the abnormality of the battery is determined from the deterioration state of the battery after the predetermined period has elapsed. Battery abnormality determination means;
When it is determined by the battery abnormality determining means that the battery is abnormal, the cooling amount by the cooling means is adjusted, and after cooling for a predetermined time with the adjusted cooling amount, the battery temperature distribution detecting means detects the battery temperature distribution detecting means. Cooling abnormality for determining whether or not the cooling means is abnormal by comparing the temperature distribution inside the battery and the temperature distribution inside the battery detected by the battery temperature distribution detecting means before adjusting the cooling amount. A determination means;
A battery cooling state determination device.   An electric vehicle including the battery cooling state determination device according to claim 1. A first step of previously holding an equivalent circuit model expressing a temperature distribution expressed by a plurality of cells constituting a battery with an equivalent circuit smaller than the number of cells;
A second step of estimating a temperature distribution inside the battery when the battery used for a predetermined period of time is normally deteriorated based on the equivalent circuit model;
Detecting a temperature of a plurality of the cells, and detecting a temperature distribution inside the battery used for the predetermined period;
A fourth step of comparing the temperature distribution estimated by the second step with the temperature distribution detected by the third step, and determining abnormality of the battery from the deterioration state of the battery after the predetermined period has elapsed; ,
The temperature distribution inside the battery detected after adjusting the cooling amount by the cooling means for cooling the battery and cooling with the adjusted cooling amount for a predetermined time when it is determined that the battery is abnormal in the fourth step And a fifth step of determining whether or not the cooling means is abnormal by comparing the temperature distribution inside the battery detected before adjusting the cooling amount;
A battery cooling state determination method including:

Images