Battery case evaluation system, battery case evaluation program, and battery case evaluation method

Abstract

A battery case evaluation system 100 for evaluating the thermal properties of a battery case BC constituting a battery pack or of a component of said battery case BC, said system being equipped with a simulation battery 10 which is installed in the battery case BC and simulates the thermal behavior of an actual battery which is a component of a battery pack, a power supply device 20 which supplies power to the simulation battery 10, and a control device 30 which controls the power supply device 20, wherein the control device 30 is configured so as to have: a parameter reception unit 31 which receives an input profile expressing the change over time in the current, voltage or power supplied to the actual battery as one evaluation parameter; a resistance value calculation unit 331 which calculates a resistance value of the actual battery which changes over time on the basis of the simulation battery temperature and the input profile; and a supply power control unit 33 which controls the power supply device 20 by using the resistance value calculated by the resistance value calculation unit 331.

Description

Battery case evaluation system, battery case evaluation program, and battery case evaluation method

[0001] The present invention relates to a battery case evaluation system, a battery case evaluation program, and a battery case evaluation method.

[0002] For example, lithium ion batteries mounted on vehicles and the like have a limited operating temperature range, and therefore require control of the operating temperature during use.

[0003] In order to properly control the operating temperature of a lithium-ion battery, it is important to consider the heat exchange between the battery case, which houses the battery and controls the battery temperature, and the battery housed in the battery case, and / or the heat exchange between the inside and outside of the battery case when the battery is housed therein.Therefore, when developing a battery case, it is necessary to know the thermal behavior of the battery.

[0004] However, during the early stages of battery case development, the design of the battery itself may be carried out in parallel, and it may not be possible to obtain a sufficient number of actual batteries, or the battery case designer may not be familiar with how to handle actual batteries. This creates a need for a simulated battery that can mimic the thermal behavior of an actual battery.

[0005] Therefore, conventionally, a resistor such as a metal plate or rod with an internal resistance similar to that of a battery is used as a simulated battery, and by passing a current with a predetermined profile through this simulated battery, the thermal behavior of an actual battery is roughly simulated.

[0006] However, the resistance value of an actual battery fluctuates from moment to moment as the temperature changes while it is energized. Conventionally, this fluctuation in resistance value has not been taken into consideration at all, and it has not been possible to accurately simulate the thermal behavior of an actual battery, and as a result, it has not been possible to accurately evaluate the thermal characteristics of the battery case or its components.

[0007] Japanese Patent Application Laid-Open No. 2022-151635

[0008] Therefore, the present invention has been made to solve the above-mentioned problems, and its object is to make it possible to simulate the thermal behavior of a battery more accurately than conventional methods in order to more efficiently evaluate battery cases.

[0009] That is, the battery case evaluation system of the present invention is a battery case evaluation system for evaluating the thermal characteristics of a battery case that constitutes a battery pack or a component of the battery case, and is equipped with a simulated battery that is installed within the battery case and simulates the thermal behavior of a real battery that is a component of the battery pack, a temperature detection means that detects the simulated battery temperature, which is the temperature of the simulated battery, a power supply device that supplies power to the simulated battery, and a control device that controls the power supply device, wherein the control device has a parameter receiving unit that receives an input profile that indicates the change over time in the current, voltage, or power supplied to the real battery as one of the evaluation parameters, a resistance value calculation unit that calculates the resistance value of the real battery that changes over time based on the simulated battery temperature and the input profile, and a supply power control unit that controls the power supply device using the resistance value calculated by the resistance value calculation unit.

[0010] The battery case evaluation system configured in this manner calculates the resistance of the real battery, which changes over time, based on the simulated battery temperature and input profile, and controls the power supply device using the calculated resistance. This allows for accurate simulation of the thermal behavior of the real battery while taking into account the constantly fluctuating resistance of the real battery, thereby enabling efficient evaluation of the battery case. Furthermore, the use of the simulated battery can avoid the risk of fire that may occur when using a real battery (e.g., damage to the electrodes due to impact during handling of the real battery or fire that may occur due to accidental overcharging). The thermal behavior of the real battery includes the heat generation behavior and / or heat absorption behavior of the real battery.

[0011] However, while a real battery is energized, not only its resistance but also its state of charge (hereinafter also referred to as SOC) fluctuates from moment to moment. Conventionally, this SOC fluctuation has not been taken into consideration at all, making it impossible to accurately simulate the thermal behavior of a real battery. Therefore, it is preferable that the control device further includes an SOC calculation unit that calculates the SOC of the real battery, which changes over time, based on the input profile, and that the resistance value calculation unit calculates the resistance value of the real battery using the SOC calculated by the SOC calculation unit in addition to the simulated battery temperature and the input profile. This configuration calculates the resistance value of the real battery while taking into account the ever-changing SOC of the real battery, thereby enabling more accurate simulation of the thermal behavior of the real battery. Furthermore, because the SOC is calculated based on the input profile, it is possible to eliminate the need for a process of repeatedly charging and discharging the real battery to create SOCs under various conditions.

[0012] It is preferable that the parameter receiving unit receives the battery capacity of the actual battery, and the SOC calculation unit calculates the SOC that changes over time using the input profile and the battery capacity, which makes it possible to simulate thermal behavior of actual batteries with various battery capacities.

[0013] Preferably, the parameter receiving unit receives at least one of an initial SOC of the real battery and an SOH of the real battery as the evaluation parameter in addition to the input profile, which makes it possible to simulate the thermal behavior of the real battery under various operating conditions.

[0014] A specific embodiment for calculating the resistance value of the actual battery may include an embodiment in which the resistance value calculation unit has a conversion table for converting the evaluation parameters received by the parameter receiving unit into resistance values, or a simulation model that outputs resistance values ​​using the evaluation parameters received by the parameter receiving unit.

[0015] Furthermore, it is preferable that the control device further includes an entropy change calculation unit that calculates an entropy change that occurs as the real battery is charged and discharged, and the supply power control unit controls the power supply device using the resistance value calculated by the resistance value calculation unit and the entropy change calculated by the entropy change calculation unit. In an actual real battery, in addition to Joule heat due to internal resistance, reaction heat is generated due to entropy changes caused by electrochemical reactions during charging and discharging. Therefore, with this configuration, the thermal behavior of the battery can be more accurately simulated by taking into account the reaction heat associated with charging and discharging in addition to Joule heat.

[0016] A specific embodiment for calculating the entropy change of the actual battery is one in which the entropy change calculation unit calculates the entropy change using table data or calculation formula data for converting the SOC calculated by the SOC calculation unit into the entropy change occurring in the actual battery.

[0017] Preferably, the simulated battery includes a heating element to which power is supplied from the power supply device and a thermal diffuser that supports the heating element and diffuses the heat generated by the heating element, and at least one of the heating element and the thermal diffuser is formed in a predetermined pattern that can reproduce the surface temperature distribution of the actual battery. Note that the term "capable of reproducing the surface temperature distribution" as used herein means not only reproducing the entire surface temperature distribution but also reproducing only a portion of the surface temperature distribution. This makes it possible to reproduce various surface temperature distributions of the actual battery, which is useful for simulating thermal behavior such as heat conduction between the actual battery and surrounding components.

[0018] It is preferable that the heating element or the heat diffusion element is formed in a predetermined sparse / dense pattern or a predetermined concave / convex pattern, so that the thermal behavior and / or heat diffusion behavior of a real battery can be simulated using the simulated battery.

[0019] It is preferable that the pattern of the heating element or the thermal diffuser is obtained by applying a machine learning model to the surface temperature distribution of the actual battery, so that a pattern for obtaining a target surface temperature distribution of the simulated battery can be obtained without using theoretical analysis, which tends to be complicated.

[0020] Furthermore, in the battery case evaluation system, it is preferable that at least one of the heating element and the thermal diffusion element is formed in a predetermined pattern that can reproduce the change in the surface temperature of the actual battery over time. In this way, it is possible to reproduce the change in various surface temperatures of the actual battery over time, and to more accurately simulate thermal behavior such as heat conduction between the actual battery and surrounding components.

[0021] In addition, the battery case evaluation program of the present invention is a battery case evaluation program for evaluating the thermal characteristics of a battery case that constitutes a battery pack or a component of the battery case, and is used in a battery case evaluation system that includes: a simulated battery that is installed in the battery case and simulates the thermal behavior of a real battery that is a component of the battery pack; a temperature detection means that detects the simulated battery temperature, which is the temperature of the simulated battery; a power supply device that supplies power to the simulated battery; and a control device that controls the power supply device, and is characterized in that the control device functions as a parameter receiving unit that receives an input profile that indicates the change over time in the current, voltage, or power supplied to the real battery as one of the evaluation parameters; a resistance value calculation unit that calculates the resistance value of the real battery that changes over time based on the simulated battery temperature and the input profile; and a supply power control unit that controls the power supply device using the resistance value calculated by the resistance value calculation unit.

[0022] Furthermore, a battery case evaluation method according to the present invention is a battery case evaluation method for evaluating the thermal characteristics of a battery case that constitutes a battery pack or components of the battery case, and is used in conjunction with a battery case evaluation system that includes a simulated battery that is installed in the battery case and simulates the thermal behavior of a real battery that constitutes the battery pack, a temperature detection means that detects a simulated battery temperature that is the temperature of the simulated battery, a power supply device that supplies power to the simulated battery, and a control device that controls the power supply device, and is characterized by comprising the steps of: having the control device accept an input profile that indicates changes over time in the current, voltage, or power supplied to the real battery as one of the evaluation parameters; having the control device calculate a resistance value of the real battery that changes over time based on the simulated battery temperature and the input profile; and having the control device control the power supply device using the calculated resistance value.

[0023] Such a battery case evaluation program and battery case evaluation method can achieve the same effects as the above-described battery case evaluation system.

[0024] According to the present invention configured as described above, it is possible to simulate the thermal behavior of a battery more accurately than before, and to evaluate the battery case efficiently.

[0025] 1 is a schematic diagram showing the overall configuration of a battery case evaluation system according to one embodiment of the present invention; FIG. 1 is a schematic diagram showing the configuration of a simulated battery case according to the same embodiment; FIG. 2 is a functional block diagram showing the function of a control device according to the same embodiment; FIG. 3 is a flowchart showing the operation of a control device according to the same embodiment; FIG. 4 is a schematic diagram showing calculation data for the control device according to the same embodiment; FIG. 5 is a schematic diagram showing the configuration of a simulated battery according to another embodiment; FIG. 6 is a schematic diagram showing the overall configuration of a battery case evaluation system according to another embodiment; FIG. 7 is a flowchart showing the operation of another control device; FIG. 8 is a functional block diagram showing the function of a control device according to another embodiment.

[0026] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a battery case evaluation system according to the present invention will be described below with reference to the drawings.

[0027] The battery case evaluation system of this embodiment is for evaluating the thermal characteristics of a battery case or components of the battery case that constitute a battery pack mounted on a vehicle such as an electric vehicle or a hybrid vehicle. Note that the battery case or components of the battery case to be evaluated are not necessarily limited to those mounted on a vehicle, but may also be those mounted on various types of moving bodies such as ships, trains, and aircraft. Furthermore, the battery case may be the various types of moving bodies themselves.

[0028] The battery pack includes, for example, a real battery (specifically, for example, a lithium-ion battery) and a battery case that houses the real battery. The battery case includes components such as a reinforcing member such as a frame, a cooling member such as a cooling plate, a heat insulating material that blocks heat from the outside, and / or electronic devices such as a junction box. The battery case may include a temperature control device such as a cooling fan that adjusts the temperature of the battery case or the battery, and a control device that controls the temperature control device, and the control device may control the temperature control device according to the temperature of the battery. The real battery may be a single real cell that is an actual battery cell, or may be a real battery module consisting of multiple real cells.

[0029] Specifically, as shown in FIG. 1, the battery case evaluation system 100 includes a simulated battery 10, a power supply device 20 that supplies power to the simulated battery 10, and a control device 30 that controls the power supply device 20.

[0030] The simulated battery 10 is intended to simulate the heat generation of an actual battery installed in the above-mentioned battery case BC, and may be a single simulated cell that simulates an actual cell, or a simulated battery module consisting of multiple simulated cells that simulates an actual battery module.

[0031] The simulated battery 10 here is a single simulated cell that simulates a single actual cell, and as shown in Figure 2, has a tab 11 connected to a power supply device 20 via wiring, a heating element 12 to which power is supplied from the power supply device 20 via the tab 11, and a thermal diffuser 13 that diffuses the heat generated by the heating element 12.

[0032] The tab 11 is connected to the power supply device 20 via wiring and is connected to the heating element 12 by welding, for example, so that it generates heat when power is supplied. This tab 11 may be the same tab 11 that is welded to an electrode (negative or positive electrode) that constitutes the actual battery, or may be one that imitates the shape, material, etc. of the tab 11.

[0033] The heating element 12 generates heat when power is supplied, and specifically, can be configured using various heaters such as a wire heater, a sheet heater, or a spot heater.

[0034] The thermal diffusion body 13 holds the heating element 12 and is made of a material with the same or similar thermal conductivity as the actual cells that make up the actual battery. Here, the heating element 12 is sandwiched between a pair of thermal diffusion bodies 13 to hold it, but the heating element 12 may be provided on only one side of the heating element 12.

[0035] 1 , the battery case evaluation system 100 of this embodiment further includes a first temperature detection means T1 for detecting the simulated battery temperature, which is the temperature of the simulated battery 10, and a second temperature detection means T2 for detecting the heating element temperature, which is the heating element 12. The first temperature detection means T1 is provided in the thermal diffuser 13, and the second temperature detection means T2 is provided in the heating element 12.

[0036] It is possible to use one or more first temperature detectors T1 and two or more second temperature detectors T2. For example, when two or more first temperature detectors T1 are used, the average value of the temperature values ​​obtained by the first temperature detectors T1 may be used. The advantage of this is that by obtaining the average value of the surface temperature distribution, the surface temperature distribution can be stably reproduced without being biased toward the high-temperature side or the low-temperature side of the temperature distribution. Conversely, for example, when evaluating a portion of the surface temperature distribution that is distributed at high temperatures, it is sufficient to install only one first temperature detector T1 near the high-temperature side.

[0037] In the simulated battery 10 of this embodiment, at least one of the heating element 12 and the thermal diffusion element 13 is formed in a predetermined pattern that can reproduce the surface temperature distribution of a real battery, thereby making it possible to reproduce the thermal behavior of a real battery, and in this case, it is possible to reproduce not only the heat generation behavior of a real battery but also the heat absorption behavior of a real battery. Note that the term "capable of reproducing the surface temperature distribution" here means not only that the entire surface temperature distribution can be reproduced, but also that a part of the surface temperature distribution can be reproduced.

[0038] In this embodiment, as shown in FIG. 2, the heating elements 12 are formed in a predetermined sparse / dense pattern.

[0039] More specifically, the heating elements 12 here are linearly arranged on the thermal diffuser 13 in a serpentine manner, for example, from one tab 11 to the other tab 11, and the surface of the thermal diffuser 13 is provided with regions where the spacing between adjacent heating elements 12 is narrow and regions where the spacing between adjacent heating elements 12 is wide. That is, the surface of the thermal diffuser 13 that holds the heating elements 12 is provided with regions where the heating elements 12 are sparsely arranged and regions where the heating elements 12 are densely arranged. With this configuration, the surface temperature of the densely arranged region can be higher than that of the sparsely arranged region.

[0040] In this embodiment, the thermal diffuser 13 is not formed in a predetermined pattern, but is, for example, in the shape of a simple flat plate. However, the thermal diffuser 13 may be formed in a predetermined pattern instead of or in addition to the heating element 12.

[0041] As shown in FIG. 1, the power supply device 20 receives a power instruction from the control device 30 and supplies power to the simulated battery 10 according to the power instruction.

[0042] The power supplied from this power supply device 20 is feedback-controlled by the control device 30, and more specifically, the surface temperature distribution or total heat generation amount of the simulated battery 10 is feedback-controlled so as to approach the surface temperature distribution or total heat generation amount of the actual battery.

[0043] The control device 30 physically comprises a CPU, memory, etc., and functionally, the CPU and its peripheral devices work together in accordance with the battery case evaluation program stored in the memory, thereby fulfilling the functions of a parameter receiving unit 31, an SOC calculation unit 32, a resistance value calculation unit 33, and a supply power control unit 34, as shown in FIG. 3.

[0044] The operation of the control device 30 will be described below with reference to the flowchart of FIG. 4, which also serves as an explanation of each component.

[0045] First, the parameter receiving unit 31 receives an input profile indicating the change over time in the current, voltage, or power applied to the actual battery as at least one of the evaluation parameters (S1).

[0046] Here, the evaluation parameters are parameters required for a simulated battery that is installed in a battery case BC and that simulates the heat generation of an actual battery that is a component of a battery pack, in a battery case evaluation system for evaluating the thermal characteristics of the battery case BC that constitutes a battery pack or the components of the battery case BC, and parameters for simulating the thermal behavior (specifically, the heat generation behavior) of the battery case BC or the components of the battery case BC that are the subject of evaluation by this battery case evaluation system 100.

[0047] This evaluation parameter is a parameter required to calculate the supply power supplied from the power supply device 20 to the simulated battery 10, and more specifically, a parameter required to obtain the resistance value of the actual battery, which is an unknown quantity when calculating the supply power.

[0048] The resistance value of the real battery fluctuates from moment to moment in accordance with changes in the temperature of the real battery while it is being energized by applying the current, etc. indicated by the input profile described above to the real battery, and therefore calculating this resistance value is important in calculating the power supply to the simulated battery 10. This is because the power supply to the simulated battery 10 is calculated based on the ratio of the resistance value of the real battery to the resistance value of the simulated battery 10.

[0049] The parameter receiving unit 31 of this embodiment receives an input profile indicating the change over time in the current applied to the actual battery 10 as at least one of the evaluation parameters.

[0050] This input profile is created in advance by the user and input to the control device 30, and specifically is a current waveform represented on a graph with one axis representing time and the other axis representing current value.

[0051] As shown in FIG. 3, the parameter receiving unit 31 of this embodiment receives, in addition to the above-described input profile, at least one of the initial SOC of the real battery and the SOH of the real battery as evaluation parameters, and here, all of these are received as evaluation parameters.

[0052] The SOC indicates the state of charge of the actual battery, the initial SOC is the SOC in the initial state before power is supplied to the actual battery, and the SOH indicates the capacity degradation of the actual battery (state of health). These evaluation parameters are set in advance by the user and input to the control device 30.

[0053] Furthermore, the parameter receiving unit 31 receives the battery capacity of the actual battery as a system parameter, in addition to the evaluation parameters.

[0054] In addition, the parameter receiving unit 31 may receive, as a system parameter, a DCR (dynamic contact resistance) profile previously acquired based on the above-mentioned input profile, or the resistance value of the heater, which is the above-mentioned heating element 12, in addition to the battery capacity of the simulated battery 10.

[0055] Some or all of the evaluation parameters received by the parameter receiving unit 31 are output to and stored in the calculation data storage unit 35 .

[0056] Next, the SOC calculation unit 32 calculates the SOC of the actual battery, which changes over time, based on the input profile described above (S2). Before calculating the SOC, a simulation time, which is the time when the simulation starts, is initialized.

[0057] Here, the SOC of the actual battery changes from moment to moment as current is supplied to the actual battery, and the SOC at any given time can be calculated by dividing the integrated value of the supplied current and time by the battery capacity of the actual battery.

[0058] Therefore, the SOC calculation unit 32 is configured to calculate the SOC that changes over time using the input profile received by the parameter reception unit 31 and the battery capacity of the actual battery.

[0059] Specifically, the SOC calculation unit 32 calculates the integrated value of the supply current to the actual battery and time based on the input profile, and divides this integrated value by the battery capacity of the actual battery to calculate the time change rate of the SOC.Then, using this time change rate and the initial SOC received by the parameter receiving unit 31, it calculates the change in SOC over time.

[0060] The SOC calculation unit 32 acquires the calculation formula, coefficients, etc. used to calculate the SOC that changes over time from the calculation data storage unit 35.

[0061] Next, the resistance value calculation unit 33 calculates the resistance value of the actual battery that changes over time when a current, voltage, or power based on the input profile is applied to the actual battery (S3).

[0062] The resistance value calculation unit 33 calculates the resistance value using at least the evaluation parameters received by the parameter reception unit 31. Specifically, the resistance value is calculated using the profile of the current supplied to the real battery, the SOC that changes over time calculated by the SOC calculation unit 32, the SOH of the real battery, and the simulated battery temperature detected by the first temperature detection means T1.

[0063] As shown in FIG. 3, the control device 30 of this embodiment further includes a calculation data storage unit 35 that stores calculation data for calculating the SOC, resistance value, and / or supplied power.

[0064] Specifically, the calculation data storage unit 35 stores a conversion table for converting the above-mentioned evaluation parameters into resistance values ​​as calculation data.

[0065] As shown in FIG. 5 , this conversion table is a three-dimensional map in which the X, Y, and Z axes are set to represent the simulated battery temperature, the resistance value of the real battery, and the SOC of the real battery. This three-dimensional map, which is a conversion table, is created in advance for each of various SOHs. For example, a three-dimensional map for the real battery is first created using a real battery. Specifically, a three-dimensional map for the real battery corresponding to each of various SOHs can be created in advance by preparing real batteries corresponding to each of various SOHs and obtaining the resistance value and SOC of the real battery when the real battery is discharged under predetermined conditions while changing the temperature of the real battery. The three-dimensional map shown in FIG. 5 was created as a three-dimensional map for the simulated battery using a previously created three-dimensional map for the real battery. Therefore, in the three-dimensional map shown in FIG. 5 , the temperature of the real battery is replaced with the temperature of the simulated battery.

[0066] Then, the resistance value calculation unit 33 calculates the resistance value of the actual battery according to the simulated battery temperature detected by the first temperature detection unit T1 and the SOC of the actual battery calculated by the SOC calculation unit 32 at each time, while referring to a three-dimensional map according to the SOH received by the parameter receiving unit 31.

[0067] The resistance value of the actual battery calculated by the resistance value calculation unit 33 in this manner is output to the power supply control unit 34 .

[0068] The supply power control unit 34 controls the power supply device 20 using the resistance value of the actual battery that changes over time calculated by the resistance value calculation unit 33 .

[0069] Specifically, this supply power control unit 34 calculates the supply current to be supplied to the simulated battery 10 based on the ratio of the resistance value of the real battery to the resistance value of the simulated battery 10 and the supply current to be supplied to the real battery (i.e., the supply current indicated by the input profile).

[0070] The resistance value of the simulated battery 10 is the resistance value of the heating element 12 to which current is supplied, and when attempting to accurately simulate the total heat generation or surface temperature distribution, the dependence of this resistance value on the temperature of the heating element 12 cannot be ignored.The supply power control unit 34 acquires the heating element temperature detected by the first temperature detection means T1 and sequentially calculates the resistance value of the simulated battery based on this heating element temperature.

[0071] The supply power control unit 34 then calculates the power to be supplied to the simulated battery 10 using the current supplied to the simulated battery 10 and the resistance value of the simulated battery 10, and outputs a power instruction indicating the magnitude of the power to be supplied to the power supply device 20 (S5). The power to be supplied can be calculated by multiplying the square of the supply current by the resistance value.

[0072] The supply power calculated by the supply power control unit 34 is output to and stored in the calculation data storage unit 35 .

[0073] 4, after outputting a power instruction to the power supply device 20, the control device 30 of this embodiment refers to the forced termination flag to determine whether or not to suspend the system operation (S6), and if forced termination is not to be performed, next refers to the sequence statement indicating the progress of the sequence to determine whether or not the preset sequence has been completed (S7). If the sequence has been completed, the system operation is terminated, and if the sequence has not been completed, the process returns to S2 and repeats the steps S2 to S7 using various data stored in the calculation data storage unit 35 at this point.

[0074] The battery case evaluation system 100 configured in this manner calculates the resistance of the actual battery, which changes over time, based on the simulated battery temperature and the input profile, and controls the power supply device 20 using the calculated resistance. This allows for accurate simulation of the thermal behavior of the actual battery while taking into account the constantly fluctuating resistance of the actual battery, thereby enabling efficient evaluation of the battery case BC. Furthermore, the use of the simulated battery 10 can avoid the risk of fire that may occur when using an actual battery (e.g., damage to the electrodes due to impact during handling of the actual battery or fire that may occur due to accidental overcharging). Furthermore, by making the resistance of the simulated battery 10 larger than that of the actual battery, it is possible to simulate the thermal behavior of a large current flowing through the actual battery by passing a small current through the simulated battery 10, thereby eliminating the need for a large facility power source.

[0075] Furthermore, since the SOC calculation unit 32 calculates the SOC of the real battery, which changes over time, based on the input profile, and the resistance value calculation unit calculates the resistance value of the real battery while taking into account the simulated battery temperature, the input profile, and the ever-changing SOC of the real battery, it is possible to more accurately simulate the thermal behavior of the real battery. Furthermore, since the SOC is calculated based on the input profile, it is possible to eliminate the need for a process of repeatedly charging and discharging the real battery to create SOCs under various conditions.

[0076] Furthermore, the parameter receiving unit 31 receives the battery capacity of the actual battery, and the battery capacity is used by the SOC calculation unit 32 to calculate the SOC, so that it is possible to simulate the thermal behavior of actual batteries of various battery capacities.

[0077] Furthermore, since the parameter receiving unit 31 receives the initial SOC and SOH of the real battery as evaluation parameters, it is possible to simulate the thermal behavior of the real battery under various operating conditions.

[0078] In addition, at least one of the heating element 12 or the thermal diffusion element 13 that make up the simulated battery 10 is formed in a predetermined pattern that can reproduce the surface temperature distribution of an actual battery, making it possible to reproduce various surface temperature distributions of an actual battery, which is useful for simulating thermal behavior such as heat conduction between the battery and surrounding components.

[0079] Furthermore, since the heating elements 12 are formed in a predetermined sparse / dense pattern, the thermal behavior of the simulated battery 10 can be made closer to the thermal behavior of an actual battery.

[0080] The present invention is not limited to the above-described embodiment.

[0081] For example, in the above embodiment, the resistance value calculation unit 33 acquires the resistance value of the simulated battery 10 using a conversion table, but the resistance value may be acquired using a simulation model created in advance. Specifically, a simulation model may be created in advance to receive the evaluation parameters accepted by the parameter acceptance unit 31 and output the resistance value of the simulated battery 10 according to the input, and the simulation model may be stored in the calculation data storage unit 35 as calculation data.

[0082] In addition, in the above embodiment, the input profile accepted by the parameter accepting unit 31 as one of the evaluation parameters indicates the change over time in the current applied to the simulated battery 10, but it may also indicate the change over time in the voltage applied to the simulated battery 10, or the change over time in the power applied to the simulated battery 10.

[0083] Furthermore, in the above embodiment, both the initial SOC and the SOH are used as evaluation parameters, but it is not necessary to use all of them, and they may be selected appropriately in consideration of the purpose of evaluation, etc.

[0084] In addition, the pattern of the heating element 12 is not limited to the meandering pattern described in the above embodiment, but may be a plurality of rectangular or circular regions as exemplified in Figures 6(a) to 6(d), or a plurality of elliptical, triangular, or polygonal regions (not shown). Specifically, the plurality of regions surrounded by the heating element 12 may all be of the same type, or may have a mixture of different shapes, and may all be of the same size, or may have a mixture of different sizes. Furthermore, the heating element may have a predetermined uneven pattern.

[0085] Furthermore, while in the above embodiment, the heating element 12 is formed with a predetermined sparse pattern, the thermal diffuser 13 may be formed with a predetermined uneven pattern, as shown in FIG. 7 . More specifically, the predetermined uneven pattern may be formed by providing recesses 121 in one or both of the surface of the thermal diffuser 13 that holds the heating element 12 and the opposite surface. The thermal diffuser 13 may also be formed with a predetermined sparse pattern. In this case, the space provided by the recesses 121 makes it more difficult for temperature to be transferred than when the heating element 12 and the thermal diffuser 13 are in direct contact with each other. As a result, it is possible to represent locally low surface temperatures on the simulated battery, and ultimately to accurately simulate the thermal diffusion behavior of a real battery using the simulated battery 10.

[0086] The predetermined pattern of one or both of the heating element 12 and the thermal diffuser 13 may be obtained by machine learning. More specifically, an example of an embodiment may use a learning model that uses the surface temperature of the actual battery as an explanatory variable and the predetermined pattern, such as the shape and density, of one or both of the heating element 12 and the thermal diffuser 13 as a target variable. In this case, the training data used for the machine learning may be, for example, a data set that associates the surface temperature distribution of the actual battery with the predetermined pattern, such as the shape and / or density, of one or both of the heating element 12 and the thermal diffuser 13.

[0087] Then, by inputting the surface temperature distribution data of the actual battery obtained in advance into the learning model, a predetermined pattern, such as the shape and / or density of one or both of the heating element 12 and the thermal spreader 13, can be output. This allows for more accurate simulation of the surface temperature distribution. Alternatively, a learning model may be used that is machine-learned by adding the time-varying change in the surface temperature distribution of the actual battery to a data set used as training data. This allows for inputting the time-varying change data of the surface temperature distribution to obtain a pattern that can simulate the surface temperature distribution. Note that when the predetermined pattern is used for one or both of the heating element 12 and the thermal spreader 13, the battery case evaluation system of the present invention does not necessarily have to include a resistance value calculation unit that calculates the time-varying resistance value of the actual battery based on the simulated battery temperature and the input profile.

[0088] Furthermore, the battery case evaluation system 100 may include a thermostatic chamber 40 that houses the simulated battery 10 and adjusts the temperature of the simulated battery 10 to a predetermined temperature, as shown in FIG.

[0089] Furthermore, the evaluation target of the battery case evaluation system 100, in other words, the destination of the power supply from the power supply device 20, may be not only the simulated battery 10, but also a battery case that includes at least a portion of a reinforcing member such as a frame, a cooling plate, a water-cooled pipe, or a cooling member such as a cooling fin, or an electronic device such as a junction box.

[0090] Furthermore, the supply power control unit 34 may perform feedback control of the power supplied to the simulated battery 10 so that the total heat generation amount of the simulated battery 10 approaches a target total heat generation amount (specifically, the total heat generation amount of the actual battery obtained in advance). With this configuration, the simulated battery 10 can be used to simulate the heat buildup in the actual battery.

[0091] The battery case evaluation system 100 according to the present invention can also be used when the change in SOC over time is not required, for example, when it is desired to perform an evaluation when the SOC of the actual battery to be simulated is at a certain value (for example, 100%), and in this case, the control device does not need to have the function of the SOC calculation unit 32.

[0092] Furthermore, in the above embodiment, the operation of the control device is in the form of a sequence, but it may be in the form of a manual operation in which various conditions are manually input each time without setting a sequence.

[0093] 9, after outputting a power instruction to the power supply device 20, the control device 30 refers to the reset flag to determine whether or not to reset the elapsed time (S8). If the elapsed time is to be reset, the control device 30 initializes the simulated time (S9) and then returns to S2. If the elapsed time is not to be reset, the control device 30 then refers to the parameter update flag to determine whether or not to change the input parameters (S10).

[0094] If the input parameters are changed in S10, the initial SOC update flag is referenced to determine whether or not to change the initial SOC (S11). If the initial SOC is to be changed, the process proceeds to S9, where the simulated time is initialized, and then returns to S2. If the initial SOC is not to be changed, the process returns to S2 without initializing the simulated time.

[0095] On the other hand, if the input parameters are not changed in S10, the end flag is then referenced to determine whether or not the simulation is to be ended (S12), and if the simulation is not to be ended, the process returns to S2.

[0096] Furthermore, although the battery case evaluation system 100 of the above embodiment is configured to calculate the resistance value of the real battery that changes over time and simulate the thermal behavior of the real battery using only the calculated resistance value, this is not limited to this. The battery case evaluation system 100 of other embodiments may be configured to calculate the entropy change that occurs as the real battery is charged and discharged, in addition to the resistance value of the real battery that changes over time, and to simulate the thermal behavior of the real battery using the calculated entropy change as well.

[0097] Specifically, in another embodiment, as shown in FIG. 10 , the control device 30 may further function as an entropy change calculation unit 36. This entropy change calculation unit 36 ​​calculates the entropy change using the SOC that changes over time calculated by the SOC calculation unit 32. The entropy change of the actual battery calculated by the entropy change calculation unit 36 ​​occurs due to electrochemical reactions during charging and discharging of the actual battery, and changes over time. In this embodiment, the calculation data storage unit 35 stores conversion table data and / or calculation formula data for converting the SOC calculated by the SOC calculation unit 32 into entropy change as entropy change calculation data. The conversion table indicated by the entropy change calculation data indicates, for example, the relationship between the SOC (%) and the entropy change ΔS (J / mol·K) at the corresponding SOC.

[0098] In a real battery, the behavior of the heat of reaction resulting from entropy change differs between charging and discharging. That is, an endothermic reaction occurs during charging, and an exothermic reaction occurs during discharging. Therefore, the calculation data storage unit 35 stores, as entropy change calculation data, first entropy change calculation data, which is data for conversion during charging, and second entropy change calculation data, which is data for conversion during discharging.

[0099] In this embodiment, the supply power control unit 34 controls the power supply device 20 using the resistance value calculated by the resistance value calculation unit 33 and the entropy change calculated by the entropy change calculation unit 36. The supply power control unit 34 calculates the supply power P to the simulated battery 10 using, for example, the following equations (1) and (2): ｅ and the supply current I ｅ Calculate the calculated supply power P ｅ and the supply current I ｅ The power supply device 20 is controlled to output the

[0100] P ｅ =I ｂ ２ ×R ｂ +(T・ΔS / F)×I ｂ (1) I ｅ = [(R ｂ / R ｎ ) × I ｂ ２ +{(T・ΔS) / (F・R ｎ )×I ｂ ] １／２ (2)

[0101] Here, R ｂ : Actual battery resistance R ｎ : Resistance value of simulated battery I ｂ : current supplied to the real battery, T: temperature of the real battery (temperature of the simulated battery), ΔS: entropy change, F: Faraday constant.

[0102] Furthermore, in a real battery, both Joule heat due to internal resistance and reaction heat (heat generation and heat absorption) resulting from entropy changes associated with charging and discharging occur, and depending on the charging and discharging conditions, the heat absorption due to reaction heat may be greater than the Joule heat, resulting in overall endothermic behavior. Therefore, the battery case evaluation system 100 of another embodiment may be equipped with a cooling mechanism for cooling the simulated battery 10. Examples of cooling mechanisms include, but are not limited to, a Peltier element, a cooling fan, and a cooling water circulator. With this configuration, the heating element 12 and the cooling mechanism can simulate not only the heat generation behavior of the battery but also its heat absorption behavior during simulated operation.

[0103] In addition, in other embodiments of the battery case evaluation system 100, if it does not have a cooling mechanism and is unable to simulate the heat absorption behavior of a real battery, it may be configured to output, for example, to a display, during the simulation operation, information that the thermal behavior of the simulated battery deviates from the thermal behavior of the real battery, and the degree of deviation.

[0104] Alternatively, in another embodiment, if the battery case evaluation system 100 does not include a cooling mechanism and is unable to simulate the heat absorbing behavior of the actual battery, the amount of heat absorbed by the actual battery during the heat absorbing behavior may be taken into account when simulating the heat generating behavior during the simulated operation. For example, by reducing the amount of heat supplied to the simulated battery during the simulated operation, the total amount of heat generated by the simulated battery 10 during the entire simulated operation may take into account both the heat generating behavior and the heat absorbing behavior of the actual battery.

[0105] In the battery case evaluation system 100 of another embodiment, the simulated battery 10 may be configured to be able to reproduce not only the surface temperature distribution of the actual battery, but also the change over time in the surface temperature of the actual battery.

[0106] In order to simulate the change in surface temperature of a real battery over time, in this embodiment, the simulated battery 10 has at least one of the heating element 12 or the thermal diffusion element 13 formed in a predetermined pattern (shape and / or density pattern) that can reproduce the change in surface temperature of a real battery over time.

[0107] Specifically, the change in the amount of heat generated in the actual battery over time is calculated using the change in the current value, voltage value or resistance value in the actual battery over time, and the change in the surface temperature of the actual battery over time is calculated based on the calculated amount of heat generated in the actual battery, and the thermal diffuser 12 or heating element 13 is formed in a predetermined shape or density pattern so that the surface temperature changes in a manner equivalent to the calculated change in the surface temperature of the actual battery over time.

[0108] In addition, the battery case evaluation system 100 may convert the calculated change in the surface temperature of the actual battery over time into the change in the amount of heat generated in the simulated battery 10 over time, calculate the change in the amount of power supplied to the simulated battery 10 over time based on the converted change in the amount of heat generated over time, and control the power supply device 20 based on the calculated change in the amount of power supplied over time.

[0109] In yet another embodiment of the battery case evaluation system 100, the heating elements 12 and / or thermal diffusers 13 may be arranged in a pattern that can reproduce the surface temperature distribution of the actual battery, for example, by operating the actual battery under various conditions in advance to determine its surface temperature distribution, and then arranging the heating elements 12 and / or thermal diffusers 13 in a predetermined pattern that can simulate the determined surface temperature distribution.

[0110] In another embodiment of the battery case evaluation system 100, the heating element 12 may be densely arranged or the thermal diffuser 13 may be sparsely arranged (or thinned) only in areas where the surface temperature of the actual battery is predicted to be high (for example, the connection part with the tab 11 and / or its surroundings), so that the temperature becomes high in those areas.

[0111] In another embodiment of the battery case evaluation system 100, the heating element 12 may be configured to have a variable resistor or a switchable circuit, or the like, so that the amount of heat generated can be adjusted by arbitrarily changing the resistance value. The control device 30 may adjust the amount of heat generated by the heating element in accordance with changes over time in the calculated or measured surface temperature distribution. In another embodiment of the battery case evaluation system 100, the position of the heating element 12 or the thermal diffuser 13 may be changeable, and the control device 30 may adjust the position of the heating element 12 or the thermal diffuser 13 in accordance with changes over time in the calculated or measured surface temperature distribution.

[0112] The disclosure of this specification also includes the battery case evaluation systems of the following aspects A to E. The disclosure of this specification also includes any combination of the components of the battery case evaluation system 100 of the above-described embodiment with the battery case evaluation systems of aspects A to E.

[0113] (Aspect A) A battery case evaluation system for evaluating thermal characteristics of a battery case constituting a battery pack or a component of the battery case, comprising: a mock battery installed within the battery case for simulating heat generation of an actual battery that is a component of the battery pack; a power supply device for supplying power to the mock battery; the mock battery having: a heating element to which power is supplied from the power supply device; and a thermal diffuser that holds the heating element and diffuses heat generated by the heating element, wherein at least one of the heating element or the thermal diffuser is formed in a predetermined pattern that can reproduce the surface temperature distribution of the actual battery.

[0114] (Aspect B) The battery case evaluation system according to Aspect A, further comprising: a temperature detection means for detecting a simulated battery temperature, which is the temperature of the simulated battery; and a control device for controlling the power supply device, wherein the control device controls the power supply device based on the temperature of the simulated battery detected by the temperature detection means and a predetermined target temperature. (Aspect C) The battery case evaluation system according to Aspect A or B, wherein the heating element or the thermal diffuser is formed in a predetermined sparse / dense pattern or a predetermined concave / convex pattern.

[0115] In the case of this aspect C, for example, the columnar heating elements may be formed in a sparse pattern, or a predetermined uneven pattern may be formed on the heating elements. Similarly, the thermal diffusers may be formed in a sparse pattern, or a predetermined uneven pattern may be formed on the heating elements.

[0116] (Aspect D) The battery case evaluation system according to any one of Aspects A to C, wherein the pattern of the heating element or the thermal diffuser is obtained by applying a machine learning model to the surface temperature distribution of the actual battery.

[0117] (Aspect E) The battery case evaluation system according to any one of Aspects A to D, wherein at least one of the heating element and the thermal diffusion element is formed in a predetermined pattern that can reproduce the change in surface temperature of the actual battery over time.

[0118] Furthermore, the present invention is not limited to the above-described embodiment, and it goes without saying that various modifications are possible without departing from the spirit of the present invention.

[0119] According to the battery case evaluation system of the present invention described above, the thermal behavior of a battery can be simulated more accurately than conventional systems.

[0120] REFERENCE SIGNS LIST 100 Battery case evaluation system 10 Simulated battery 11 Tab 12 Heat generating element 13 Thermal diffusion element 20 Power supply device 30 Control device 31 Parameter receiving unit 32 SOC calculation unit 33 Resistance value calculation unit 34 Supply power control unit 35 Calculation data storage unit

Claims

1. A battery case evaluation system for evaluating the thermal characteristics of a battery case or components of a battery case that constitute a battery pack, A simulated battery installed inside the battery case to simulate the thermal behavior of an actual battery which is a component of the battery pack, A temperature detection means for detecting the simulated battery temperature, which is the temperature of the simulated battery, A power supply device that supplies power to the aforementioned simulated battery, The system comprises a control device for controlling the aforementioned power supply device, The control device, A parameter receiving unit that accepts an input profile showing the change over time of current, voltage, or power supplied to the actual battery as one of the evaluation parameters, A resistance value calculation unit calculates the resistance value of the actual battery, which changes over time, based on the simulated battery temperature and the input profile. A battery case evaluation system comprising a power supply control unit that controls the power supply device using the resistance value calculated by the resistance value calculation unit.

2. The control device further includes an SOC calculation unit that calculates the SOC of the actual battery which changes over time based on the input profile. The battery case evaluation system according to claim 1, wherein the resistance value calculation unit calculates the resistance value of the actual battery using the SOC calculated by the SOC calculation unit in addition to the simulated battery temperature and the input profile.

3. The parameter receiving unit receives the battery capacity of the actual battery, The battery case evaluation system according to claim 2, wherein the SOC calculation unit calculates the SOC that changes over time using the input profile and the battery capacity.

4. The battery case evaluation system according to any one of claims 1 to 3, wherein the parameter receiving unit accepts, in addition to the input profile, at least one of the initial SOC of the actual battery or the SOH of the actual battery as the evaluation parameter.

5. The battery case evaluation system according to any one of claims 1 to 3, wherein the resistance value calculation unit has a conversion table for converting the evaluation parameters received by the parameter receiving unit into resistance values, or a simulation model that outputs resistance values ​​using the evaluation parameters received by the parameter receiving unit.

6. The control device further includes an entropy change calculation unit that calculates the entropy change that occurs with the charging and discharging of the actual battery, The battery case evaluation system according to any one of claims 1 to 3, wherein the power supply control unit controls the power supply device using the resistance value calculated by the resistance value calculation unit and the entropy change calculated by the entropy change calculation unit.

7. The battery case evaluation system according to claim 6, which references claim 2 or 3, wherein the entropy change calculation unit calculates the entropy change using table data or calculation formula data for converting the SOC calculated by the SOC calculation unit into an entropy change occurring in the actual battery.

8. The aforementioned simulated battery, A heating element to which power is supplied from the aforementioned power supply device, The system includes a heat diffuser that holds the heat-generating element and diffuses the heat emitted by the heat-generating element, The battery case evaluation system according to any one of claims 1 to 3, wherein at least one of the heating element or the heat diffusing element is formed in a predetermined pattern capable of reproducing the surface temperature distribution of the actual battery.

9. The battery case evaluation system according to claim 8, wherein the simulated battery has a cooling mechanism for cooling itself.

10. The battery case evaluation system according to claim 8, wherein the heating element or the heat diffusing element is formed with a predetermined density pattern or a predetermined uneven pattern.

11. The battery case evaluation system according to claim 8, wherein the pattern of the heating element or the heat diffuser is obtained by applying a machine learning model to the surface temperature distribution of the actual battery.

12. The battery case evaluation system according to claim 8, wherein at least one of the heating element or the heat diffusing element is formed in a predetermined pattern capable of reproducing the change in surface temperature of the actual battery over time.

13. A battery case evaluation program for evaluating the thermal characteristics of a battery case or components of a battery case that constitute a battery pack, used in a battery case evaluation system comprising: a simulated battery installed inside the battery case to simulate the thermal behavior of an actual battery which is a component of the battery pack; a temperature detection means for detecting the simulated battery temperature, which is the temperature of the simulated battery; a power supply device for supplying power to the simulated battery; and a control device for controlling the power supply device. The control device, A parameter receiving unit that accepts an input profile showing the change over time of current, voltage, or power supplied to the actual battery as one of the evaluation parameters, A resistance value calculation unit calculates the resistance value of the actual battery, which changes over time, based on the simulated battery temperature and the input profile. A battery case evaluation program that functions as a power supply control unit, controlling the power supply device using the resistance value calculated by the resistance value calculation unit.

14. A battery case evaluation method for evaluating the thermal characteristics of a battery case or components of a battery case that constitute a battery pack, This method is used in conjunction with a battery case evaluation system comprising: a simulated battery installed inside the battery case to simulate the thermal behavior of an actual battery which is a component of the battery pack; a temperature detection means for detecting the simulated battery temperature, which is the temperature of the simulated battery; a power supply device for supplying power to the simulated battery; and a control device for controlling the power supply device. The steps include: causing the control device to accept an input profile showing the change over time of the current, voltage, or power supplied to the actual battery as one of the evaluation parameters; The control device is instructed to calculate the resistance value of the actual battery, which changes over time, based on the simulated battery temperature and the input profile. A battery case evaluation method comprising the step of causing the control device to control the power supply device using the calculated resistance value.