System for predicting internal electrical resistance of secondary battery and method for predicting internal electrical resistance of secondary battery

Abstract

Focusing on the heat generation of the battery 1, the internal electrical resistance is estimated by simple processing. [Solution] The increase or decrease in thermal energy based on changes in the temperature of battery 1, the heat of reaction based on the physical properties of battery 1, and the amount of heat transferred (amount of heat transfer) from battery 1 to the heat medium 6 that cools battery 1 are grasped, and the internal electrical resistance of battery 1 is grasped by dividing the value based on the increase or decrease in thermal energy, heat of reaction, and amount of heat transfer by a value based on the charge / discharge current of battery 1.

Description

[Technical Field]

[0001] The present invention relates to a system for predicting the internal electric resistance of a secondary battery and a method for predicting the internal electric resistance of a secondary battery. [Background technology]

[0002] For example, secondary batteries for electric vehicles deteriorate due to repeated charging and discharging, inappropriate usage environments (high and low temperature environments), overcharging and over-discharging, etc. As deterioration progresses, the internal electrical resistance of the battery increases, so the results of predicting internal electrical resistance can be used as one index for evaluating battery deterioration.

[0003] A known technique for estimating the internal electrical resistance of an electric vehicle battery is to calculate the internal electrical resistance of the battery based on the current values ​​of the discharge current and charge current during a desired driving time (for example, Patent Document 1). The technique in Patent Document 1 is capable of accurately estimating the internal electrical resistance of the battery regardless of the magnitude of the variance in the current values.

[0004] Conventional technology estimates the internal electrical resistance of a battery based on the current value situation, so it is necessary to take into account the current value situation depending on the expected situation, and the reality is that the process for calculating the internal electrical resistance may become complicated. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2022-14216 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a system for predicting the internal electrical resistance of a secondary battery, and a method for predicting the internal electrical resistance of a secondary battery, which focus on heat generation in the secondary battery and can estimate the internal electrical resistance according to the operating conditions of the equipment. [Means for solving the problem]

[0007] In order to achieve the above object, the system for predicting the internal electrical resistance of a secondary battery according to claim 1 of the present invention comprises: a battery temperature detection means for detecting the temperature of a secondary battery mounted in the device and serving as a power source for the driving means; a current deriving means for deriving a charge / discharge current (I) of the secondary battery; A physical property determining means for determining physical properties related to the reaction heat of the secondary battery (mass, specific heat at constant pressure, voltage, temperature, entropy coefficient, etc.: physical properties related to Qe); a heat medium temperature detection means for detecting a temperature of a heat medium for cooling the secondary battery; a heat transfer index deriving means for deriving a heat transfer index which is an index relating to heat transfer between the secondary battery and the heat medium; a charging / discharging means for charging / discharging the secondary battery; and a control means for inputting information from the battery temperature detection means, the current derivation means, the physical property determination means, the heat medium temperature detection means, and the heat transfer index derivation means, and determining the internal electrical resistance (r) of the secondary battery based on the physical property related to the reaction heat of the secondary battery, the temperature between the secondary battery and the heat medium, the charge / discharge current (I) of the secondary battery, and the heat transfer index between the secondary battery and the heat medium. It is characterized by:

[0008] In the present invention according to claim 1, the internal electrical resistance of a secondary battery is determined based on physical properties related to the reaction heat of the secondary battery, the temperature between the secondary battery and the heat medium, the charge / discharge current (I) of the secondary battery, and a heat transfer index (e.g., the amount of heat transfer) between the secondary battery and the heat medium. Therefore, the internal electrical resistance of a secondary battery that is mounted in a device and serves as a drive source for a drive means can be determined in accordance with heat generation during the operation of the device.

[0009] Therefore, it becomes possible to focus on the heat generation of the secondary battery and estimate the internal electrical resistance depending on the operating conditions of the device.

[0010] The system for predicting the internal electrical resistance of a secondary battery according to the present invention as set forth in claim 2 is as follows: The system for predicting the internal electrical resistance of a secondary battery according to claim 1, The control means a heat change index deriving function for determining a heat change index (Qx) of the increase or decrease in thermal energy of the secondary battery based on the temperature change detected by the battery temperature detection means; an entropy index derivation function for calculating an index (Qe) of reaction heat based on an entropy change of the secondary battery based on the physical properties related to the reaction heat of the secondary battery grasped by the physical property grasping means; the heat transfer index deriving means having a heat transfer amount deriving function for determining a heat transfer amount (Qa) from the secondary battery to the heat medium based on the temperatures of the secondary battery and the heat medium and the heat transfer index; an internal electrical resistance estimation function that receives as input the heat change index (Qx) calculated by the heat change index (Qx) deriving function, the index (Qe) of reaction heat based on the entropy change calculated by the entropy index (Qe) deriving function, and the amount of heat transfer (Qa) calculated by the amount of heat transfer deriving function, and that estimates the internal electrical resistance (r) by dividing the heat change index (Qx), the entropy index (Qe), and the amount of heat transfer (Qa) by the state of the charge / discharge current (I) of the secondary battery; It is characterized by:

[0011] In the present invention according to claim 2, the internal electrical resistance can be estimated according to the heat generation situation by estimating the internal electrical resistance by dividing a value based on the heat change index (Qx), entropy index (Qe), and heat transfer amount (Qa) by the charge / discharge current situation.

[0012] Specifically, the physical properties related to the reaction heat of the secondary battery (mass of the secondary battery, specific heat at constant pressure, entropy change coefficient), the flow rate of the heat transfer medium, specific heat at constant pressure, the charge / discharge current (I) of the secondary battery, the temperature between the secondary battery and the heat transfer medium, and the state of the charge / discharge current (I) based on the amount of heat transfer to the heat transfer medium, for example, I 2 The value divided by this is estimated as the internal electrical resistance (r).

[0013] This makes it possible to determine the internal electrical resistance (r) of the secondary battery based on the effect of reaction heat of the secondary battery due to entropy change (Qe), the increase or decrease in thermal energy due to temperature change (Qx), the flow rate of the heat transfer medium, and the amount of heat transfer based on the specific heat at constant pressure (Qa).

[0014] By controlling the secondary battery in a section where the state of charge (SOC) and / or temperature are the same at the beginning and end, the influence of heat due to entropy change and / or temperature change can be eliminated, and the internal electrical resistance (r) of the secondary battery can be determined according to the operating conditions of the equipment based only on the amount of heat transfer of the heat medium.

[0015] Furthermore, the internal electrical resistance prediction system for a secondary battery of the present invention according to claim 3 is characterized in that in the internal electrical resistance prediction system for a secondary battery according to claim 2, the heat transfer amount (Qa) derivation function derives the heat transfer amount based on the temperature difference of the heat medium at the inlet and outlet of the heat medium and the flow rate (heat transfer index) of the heat medium.

[0016] In the present invention according to claim 3, the amount of heat transfer is derived based on the temperature difference between the secondary battery and the heat medium at the inlet and outlet of the heat medium, and the flow rate of the heat medium, so that the detected parameters can be used as they are to determine the amount of heat transfer.

[0017] Furthermore, the internal electrical resistance prediction system for a secondary battery of the present invention according to claim 4 is characterized in that in the internal electrical resistance prediction system for a secondary battery according to claim 2, the heat transfer amount (Qa) derivation function derives the heat transfer amount based on a coefficient related to the temperature difference between any point of the secondary battery and the heat medium, and the heat transfer rate (heat transfer index) from the secondary battery to the heat medium.

[0018] In the present invention according to claim 4, the amount of heat transfer is derived based on the temperature difference between the secondary battery and any location (for example, any one location) of the heat medium and a coefficient related to the rate of heat transfer to the heat medium, so that the amount of heat transfer can be derived using a small number of detection parameters.

[0019] Furthermore, the internal electrical resistance prediction system for a secondary battery of the present invention according to claim 5 is characterized in that, in the internal electrical resistance prediction system for a secondary battery according to any one of claims 1 to 4, the control device grasps the internal electrical resistance (r) during the process of driving the driving means of the equipment.

[0020] In the present invention according to claim 5, in the process of driving the driving means of the device, for example, the drive motor of an electric vehicle is driven and the internal electric resistance (r) is grasped while the electric vehicle is running.

[0021] In order to achieve the above object, the method for predicting the internal electrical resistance of a secondary battery of the present invention according to claim 6 is characterized in that it determines the internal electrical resistance (r) of the secondary battery by determining a heat change index (Qx) of the increase or decrease in thermal energy based on a change in the temperature of the secondary battery, an entropy index (Qe) of the heat of reaction calculated from the current, temperature, and entropy coefficient of the secondary battery, and the amount of heat transferred from the secondary battery to a heat medium that cools the secondary battery (amount of heat transfer: Qa), and dividing a value based on the heat change index (Qx), entropy index (Qe), and amount of heat transfer (Qa) by a value based on the charge / discharge current (I) of the secondary battery.

[0022] In the present invention according to claim 6, the internal electrical resistance of a secondary battery can be easily estimated using information on heat based on the increase or decrease in thermal energy due to changes in the temperature of the secondary battery, the heat of reaction calculated from the current, temperature, and entropy coefficient of the secondary battery, and the amount of heat transferred (amount of heat transferred) from the secondary battery to the heat medium, without the need for complex processing.

[0023] Therefore, it becomes possible to focus on the heat generation of the secondary battery and estimate the internal electrical resistance depending on the operating conditions of the device. [Effects of the Invention]

[0024] The system for predicting the internal electrical resistance of a secondary battery and the method for predicting the internal electrical resistance of a secondary battery of the present invention focus on the heat generation of the secondary battery and make it possible to estimate the internal electrical resistance according to the operating conditions of the device. [Brief explanation of the drawings]

[0025] [Figure 1] 1 is a schematic configuration diagram of an electric vehicle to which a system for predicting the internal electrical resistance of a secondary battery according to an embodiment of the present invention is applied; [Figure 2] 1 is a schematic diagram of a system for predicting the internal electrical resistance of a secondary battery according to an embodiment of the present invention. [Figure 3] FIG. 2 is a block diagram of a control means. [Figure 4] FIG. 1 is a conceptual diagram illustrating heat transfer. [Figure 5] 1 is a graph showing changes in the SOC and temperature of a battery over time. [Figure 6] FIG. 10 is a conceptual diagram illustrating the progress of processing. [Figure 7] FIG. 10 is a formula diagram illustrating an example of heat quantity. [Figure 8] FIG. 10 is a formula diagram illustrating an example of heat quantity. [Figure 9] FIG. 2 is a formula for explaining internal electrical resistance. DETAILED DESCRIPTION OF THE INVENTION

[0026] An embodiment of the system for predicting the internal electrical resistance of a secondary battery according to the present invention will be described with reference to FIGS.

[0027] FIG. 1 shows a schematic configuration of an electric vehicle to which a system for predicting the internal electrical resistance of a secondary battery according to one embodiment of the present invention is applied, and FIG. 2 shows a schematic system for explaining the configuration of a system for predicting the internal electrical resistance of a secondary battery according to one embodiment of the present invention.

[0028] As shown in Fig. 1, an electric vehicle 21 as a device is provided with a motor 22 as a drive means, and the motor 22 is provided with a battery 1, which is a secondary battery, as a power source via an inverter 23. The charging and discharging (charging and discharging) of the battery 1 is controlled via a charging and discharging means 3 according to the running of the electric vehicle 21. A cooling means 5 for cooling the battery 1 is provided, and a heat medium (refrigerant: air, water, etc.) 6 for cooling the battery 1 flows through the cooling means 5.

[0029] As will be described in detail later, the internal electrical resistance prediction system of the present invention has a control means 4 that grasps the internal electrical resistance (r) of the battery 1 based on the temperature of the battery 1, the charge / discharge current, the current related to the heat of reaction, the entropy status, the temperature of the heat transfer medium 6, and the status of the index of heat transfer (heat transfer index) between the battery 1 and the heat transfer medium 6 (heat transfer index derivation means).

[0030] As shown in Fig. 2, a battery temperature detection means 2 is provided for detecting the temperature (Tb) of the battery 1. The charge / discharge current (I) of the battery 1 is determined (derived: current derivation means) by a charge / discharge means 3. A cooling means 5 for cooling the battery 1 is provided with a heat medium temperature detection means 7 for detecting the temperature of the heat medium 6, and the heat medium temperature detection means 7 are provided on the inlet side and outlet side of the cooling means 5.

[0031] Information on the temperature (Ta, in) of the heat medium 6 on the inlet side of the cooling means 5 and the temperature (Ta, out) of the heat medium 6 on the outlet side, detected by the heat medium temperature detection means 7, is input to the control means 4. Information on the flow rate (ma) and specific heat at constant pressure (Cpa) of the heat medium 6 is also input to the control means 4.

[0032] Information from the battery temperature detection means 2, current derivation means (charge / discharge means 3), heat medium temperature detection means 7, and heat transfer index derivation means is input to the control means 4. In addition, the control means 4 receives (stores) information on the current, entropy status, and physical properties (information on mass Mb, specific heat at constant pressure Cpb, voltage, etc.) related to the reaction heat of the battery 1 (physical property grasping means).

[0033] The control means 4 determines a heat change index (Qx) of the increase or decrease in thermal energy of the battery 1 based on the temperature change detected by the battery temperature detection means 2 (heat change index derivation function). Also, based on the physical properties related to the heat generation of the battery 1, such as the mass Mb and the constant pressure specific heat Cpb, determined by the physical property determination means, a reaction heat index (Qe) based on the entropy change of the battery 1 is determined (entropy index derivation function). Furthermore, as a heat transfer index derivation means, the amount of heat transfer (Qa) from the battery 1 to the heat transfer medium 6 is determined based on the temperatures of the battery 1 and the heat transfer medium 6 and the heat transfer index (heat transfer amount derivation function).

[0034] The heat transfer amount derivation function derives a heat transfer index (for example, an index related to heat transfer derived from the battery 1, the specific heat at constant pressure of the heat medium 6, physical properties such as thermal conductivity, density, viscosity related to heat transfer speed, and the flow rate of the heat medium 6) which is an index of heat transfer between the battery 1 and the heat medium 6, based on the difference (temperature difference between the inlet and outlet sides) between the temperature (Ta, in) of the heat medium 6 on the inlet side of the cooling means 5 and the temperature (Ta, out) of the heat medium 6 on the outlet side, the flow rate (ma) of the heat medium 6, and the specific heat at constant pressure (Cpa). Specifically, as will be described later, the heat transfer amount (Qa) is calculated based on the heat transfer index derived by the heat transfer index derivation means.

[0035] That is, the amount of heat transfer (Qa) is calculated based on the difference between the inlet temperature (Ta, in) and outlet temperature (Ta, out) of the heat transfer medium 6, and the flow rate (ma) of the heat transfer medium 6.

[0036] The heat transfer index, which is an index of heat transfer between the battery 1 and the heat medium 6, can also be calculated by calculating the heat transfer amount from the temperature difference between any point (for example, any one point) between the battery 1 and the heat medium 6 and an index related to the heat transfer speed to the heat medium 6. This makes it possible to derive the heat transfer amount (Qa) using fewer detection parameters.

[0037] The control means 4 is configured to grasp the internal electrical resistance (r) of the battery 1 based on the charge / discharge current (I) of the battery 1, the heat change index (Qx) of the increase / decrease in thermal energy of the battery 1, the reaction heat index (Qe) based on the entropy change of the battery 1, and the amount of heat transfer (Qa) from the battery 1 to the heat transfer medium 6.

[0038] This makes it possible to grasp the internal electrical resistance (r) of the battery 1 based on the charge / discharge current (I) of the battery 1 and the heat generation state of the battery 1.

[0039] By controlling the start and end of the control period in a period where the SOC and temperature Tb of battery 1 are the same, the effects of heat due to entropy changes and temperature changes can be eliminated, and the internal electrical resistance (r) of battery 1 can be determined based on the amount of heat transfer in the heat medium.

[0040] The function of the control means 4 will be specifically described with reference to Fig. 3. Fig. 3 shows a block diagram for explaining the function of the control means 4.

[0041] As shown in the figure, the control means 4 has a heat change index derivation function 11 that determines the heat change index (Qx) of the increase or decrease in thermal energy of the battery 1 based on the mass and constant pressure specific heat of the battery 1 determined by the physical property determination means, and changes in the temperature Tb detected by the battery temperature detection means 2. It also has an entropy index derivation function 12 that determines the reaction heat index (Qe) based on the entropy change of the battery 1 based on the current, entropy status, and physical property information (information such as mass Mb, constant pressure specific heat Cpb, and voltage) related to the reaction heat of the battery 1 determined by the physical property determination means.

[0042] In addition, a heat transfer index (index related to heat transfer), which is an index of heat transfer between the battery 1 and the heat medium 6, is calculated based on the difference between the inlet temperature (Ta, in) and outlet temperature (Ta, out) of the heat medium 6, the flow rate (ma) of the heat medium 6, and the specific heat at constant pressure (Cpa), and the heat transfer amount derivation function 13 (heat transfer index derivation means) derives the heat transfer amount (Qa) based on the heat transfer index.

[0043] The system has an internal electrical resistance estimation function 14 that inputs the heat change index (Qx) of the increase or decrease in thermal energy, the reaction heat index (Qe) based on the entropy change, and the amount of heat transfer (Qa), and estimates the internal electrical resistance (r) by dividing the heat change index (Qx), the reaction heat index (Qe), and the amount of heat transfer (Qa) by the charge / discharge current (I) of the battery 1.

[0044] Therefore, the internal electrical resistance estimation function 14 determines the internal electrical resistance (r) of the battery 1 based on the heat change index (Qx) of the increase or decrease in thermal energy, the reaction heat index (Qe) based on the entropy change, and the amount of heat transfer (Qa).

[0045] The situation of determining the internal electric resistance (r) of the battery 1 will be specifically described with reference to Fig. 4. Fig. 4 shows a schematic system for conceptually explaining the heat transfer in the internal electric resistance prediction device.

[0046] The heat generation (Qb) of the battery 1 is expressed by the following equation (1). Qb=(I 2r) Δτ+(Qe) (1) Qe: Reaction heat due to entropy change during charging and discharging, which can be expressed, for example, by the formula shown in FIG. Δτ: Accumulation time

[0047] The increase or decrease in the thermal energy of the battery 1 (thermal change index: Qx) is expressed by the following equation (2). Qx = Qb - Qa (2) The amount of heat transfer (Qa) is based on the amount of heat transferred based on the flow rate of the heat medium and the specific heat at constant pressure, and can be expressed by the formula shown in FIG. 8, for example. From equations (1) and (2), Qx=(I 2 r) Δτ+Qe-Qa (3) This becomes:

[0048] According to equation (3), the internal electrical resistance (r) of battery 1 is expressed by the following equation (4). r=(Qx+Qa-Qe) / (I 2 Δτ) (4) That is, the internal electrical resistance (r) can be expressed by the formula shown in FIG.

[0049] The parameters indicated by the symbols in the figure are as follows: Mb: Mass of battery 1 Cpa: specific heat at constant pressure of heat medium 6 Cpb: specific heat at constant pressure of battery 1 Ta: Temperature of heat medium 6 Tb: Temperature of battery 1 ma: mass flow rate of heat medium 6 τ: time U: Voltage dU / dT: Entropy change coefficient

[0050] In this embodiment, the internal electrical resistance (r) can be estimated using equation (4), for example, the equation shown in FIG. 9, based on the heat change index (Qx) of the increase or decrease in thermal energy, the reaction heat index (Qe) based on the entropy change, and the amount of heat transfer (Qa).

[0051] Therefore, by focusing on the heat generation of the battery 1, it becomes possible to estimate the internal electrical resistance of the battery 1 according to the driving conditions of the electric vehicle 21 while the vehicle is being driven.

[0052] Based on Figures 5 and 6, a specific example of the operating status of battery 1 using the internal electrical resistance prediction system (a method for predicting internal electrical resistance according to the operation of electric vehicle 21) when estimating the internal electrical resistance (r) of battery 1 using equation (4) will be described.

[0053] FIG. 5 is a graph showing an example of the SOC and temperature change over time of the battery 1 (an example of running the electric vehicle 21), and FIG. 6 shows a concept explaining the charging and discharging process and the progress of heat transfer for the battery 1.

[0054] In Fig. 5, the SOC status is shown by a solid line, and the temperature (Tb) status is shown by a dashed line. Fig. 6(a) conceptually shows the status during discharging (for example, when the electric vehicle 21 is running on power from the battery 1), and Fig. 6(b) conceptually shows the status during charging (when the electric vehicle 21 is charging while stopped).

[0055] As shown in Fig. 5, between time τ0 and time τ1, the electric vehicle 21 runs, the battery 1 discharges from SOC1 (the state of Fig. 6(a)), and the SOC drops to SOC2. Between time τ1 and time τ2, the electric vehicle 21 stops, and the SOC is maintained at SOC2. During this time, the temperature of the battery 1 rises from Tb1 to Tb2 and drops from Tb2 to Tb3.

[0056] Between time τ2 and time τ3, the battery 1 of the electric vehicle 21 is charged at a charging station or the like (state in FIG. 6(b)), and the SOC increases from SOC2 to SOC3. Between time τ3 and time τ4, the electric vehicle 21 starts running again, and the SOC decreases from SOC3 to SOC4. During this time, the temperature of the battery 1 increases from Tb3 to Tb4.

[0057] In the above-described example of the running state of the electric vehicle 21, for example, during the discharge time from time τ0 to time τ1 or during the discharge time from time τ2 to time τ3, the internal electrical resistance (r) of the battery 1 is estimated by equation (4) based on the heat change index (Qx) of the increase or decrease in thermal energy, the reaction heat index (Qe) based on the entropy change, the heat transfer amount (Qa), and the current (I).

[0058] For example, during the discharge time between SOC1a at time τa and SOC1b at time τb, the internal electrical resistance (r) of battery 1 is estimated using equation (4) based on the heat change index (Qx) of the increase or decrease in thermal energy, the reaction heat index (Qe) based on the entropy change, the amount of heat transfer (Qa), and the current (I).

[0059] Furthermore, for example, during the charging time between SOC2c at time τc and SOC2d at time τd, the internal electrical resistance (r) of battery 1 is estimated using equation (4) based on the heat change index (Qx) of the increase or decrease in thermal energy, the reaction heat index (Qe) based on the entropy change, the amount of heat transfer (Qa), and the current (I).

[0060] Therefore, it is possible to estimate the internal electrical resistance (r) of the battery 1 in any (desired) operating state when discharging or charging the electric vehicle 21. For example, it is possible to estimate the internal electrical resistance (r) of the battery 1 as needed in a situation where calculations can be easily performed according to any charge / discharge amount per unit time.

[0061] The above-described internal electrical resistance prediction system and internal electrical resistance prediction method make it possible to estimate the internal electrical resistance of the battery 1 while the battery 1 is mounted on the electric vehicle 21 and during operation, focusing on the heat generation of the battery 1 and depending on the operating conditions of the electric vehicle 21 (while the electric vehicle 21 is operating).

[0062] If the SOC of Battery 1 is the same at the start and end of control, there is no need to consider the index of reaction heat (Qe) based on entropy change, so the heat generation index (Qe) on the right side of the denominator can be ignored in the equation shown in Figure 9. Alternatively, if the temperature of Battery 1 is the same at the start and end of control, there is no need to consider the amount of heat transfer (Qa), so the amount of heat transfer (Qa) on the left side of the denominator can be ignored in the equation shown in Figure 9.

[0063] Furthermore, if the SOC and temperature of Battery 1 are the same at the start and end of control, there is no need to consider the reaction heat index (Qe) and heat transfer amount (Qa) based on entropy change, so the heat generation index (Qe) and heat transfer amount (Qa) on the left side of the denominator can be ignored in the equation shown in Figure 9. In other words, the internal electrical resistance of Battery 1 can be estimated during operation using only the heat change index (Qx) of the increase or decrease in thermal energy (without requiring information on physical properties such as Battery 1's mass, constant pressure specific heat, or temperature). [Industrial Applicability]

[0064] The present invention can be used in industrial fields for a system for predicting the internal electrical resistance of a secondary battery and a method for predicting the internal electrical resistance of a secondary battery. [Explanation of symbols]

[0065] 1 battery 2. Battery temperature detection means 3 Charging / discharging means 4. Control Measures 5 Cooling means 6 Heat medium 7 Heat medium temperature detection means 11. Heat change index derivation function 12 Entropy index derivation function 13 Heat transfer amount derivation function 14 Internal electrical resistance estimation function 21 Electric vehicles 22 Motor 23 Inverter

Claims

1. a battery temperature detection means for detecting the temperature of a secondary battery mounted in the device and serving as a power source for the driving means; a current deriving means for deriving a charge / discharge current of the secondary battery; a physical property determining means for determining a physical property related to the reaction heat of the secondary battery; a heat medium temperature detection means for detecting a temperature of a heat medium for cooling the secondary battery; a heat transfer index deriving means for deriving a heat transfer index which is an index relating to heat transfer between the secondary battery and the heat medium; a charging / discharging means for charging / discharging the secondary battery; and a control means for inputting information from the battery temperature detection means, the current derivation means, the physical property determination means, the heat medium temperature detection means, and the heat transfer index derivation means, and determining the internal electrical resistance of the secondary battery based on the physical properties of the secondary battery, the temperatures of the secondary battery and the heat medium, the charge / discharge current of the secondary battery, and the heat transfer index between the secondary battery and the heat medium. A system for predicting the internal electrical resistance of a secondary battery.

2. 2. The system for predicting internal electrical resistance of a secondary battery according to claim 1, The control means a heat change index deriving function for determining a heat change index of an increase or decrease in thermal energy of the secondary battery based on a temperature change detected by the battery temperature detecting means; an entropy index derivation function for determining an index of reaction heat based on an entropy change of the secondary battery based on the physical properties related to the secondary battery grasped by the physical property grasping means; the heat transfer index deriving means has a heat transfer amount deriving function for determining a heat transfer amount from the secondary battery to the heat medium based on temperatures of the secondary battery and the heat medium and the heat transfer index; an internal electrical resistance estimation function that receives the heat change index obtained by the heat change index derivation function, the reaction heat index based on the entropy change obtained by the entropy index derivation function, and the heat transfer amount obtained by the heat transfer amount derivation function, and estimates the internal electrical resistance as the value obtained by dividing the heat change index, the reaction heat index based on the entropy change, and the heat transfer amount by the state of charge / discharge current of the secondary battery; A system for predicting the internal electrical resistance of a secondary battery.

3. 3. The system for predicting the internal electrical resistance of a secondary battery according to claim 2, In the heat transfer amount deriving function, The amount of heat transfer is calculated based on the temperature difference between the inlet and outlet of the heat transfer medium and the flow rate of the heat transfer medium (heat transfer index). A system for predicting the internal electrical resistance of a secondary battery.

4. 3. The system for predicting the internal electrical resistance of a secondary battery according to claim 2, In the heat transfer amount deriving function, The amount of heat transfer is calculated based on a temperature difference between any point of the secondary battery and the heat medium, and a coefficient related to a rate of heat transfer from the secondary battery to the heat medium. A system for predicting the internal electrical resistance of a secondary battery.

5. 5. The system for predicting the internal electric resistance of a secondary battery according to claim 1, wherein the control device grasps the internal electric resistance during the driving process of the driving means of the device. A system for predicting the internal electrical resistance of a secondary battery.

6. a thermal change index (Qx) of the increase or decrease in thermal energy based on the change in temperature of the secondary battery; and an entropy index (Qe) of the reaction heat calculated from the current, temperature, and entropy coefficient of the secondary battery; The amount of heat transferred from the secondary battery to the heat medium that cools the secondary battery (heat transfer amount: Qa) is determined, and a value based on the heat change index (Qx), the entropy index (Qe), and the heat transfer amount (Qa) is divided by a value based on the charge / discharge current (I) of the secondary battery to determine the internal electrical resistance (r) of the secondary battery. A method for predicting the internal electrical resistance of a secondary battery.

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