EP-4737919-A1 - BATTERY CASE EVALUATION SYSTEM, BATTERY CASE EVALUATION PROGRAM, AND BATTERY CASE EVALUATION METHOD

EP4737919A1EP 4737919 A1EP4737919 A1EP 4737919A1EP-4737919-A1

Abstract

This invention is a battery case evaluation system 100 for evaluating thermal characteristics of a battery case (BC) constituting a battery pack or a component of the battery case (BC). The battery case (BC) comprises a simulated battery 10 that is installed within the battery case (BC) and that is to simulate thermal behavior of the actual battery which is a component of the battery pack, 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. The control device 30 comprises a parameter receiving unit 31 that receives an input profile indicating time-dependent change of a current, a voltage, or power supplied to the actual battery as one of evaluation parameters, a resistance value calculation unit 331 that calculates a resistance value of the actual battery which changes over time based on simulated battery temperature and the input profile, and a power supply control unit 33 that controls the power supply device 20 using the resistance value calculated by the resistance value calculation unit 331.

Inventors

MATSUNAGA, Shimpachi
HATAKEYAMA, HIROSHI
TATSUKAWA, Shogo

Assignees

HORIBA, Ltd.

Dates

Publication Date: 20260506
Application Date: 20240628

Claims (14)

A battery case evaluation system for evaluating thermal characteristics of a battery case constituting a battery pack or a component part of the battery case, comprising, a simulated battery that is installed within the battery case for simulating thermal behavior of an actual battery which is a component part of the battery pack, a temperature detection device that detects a simulated battery temperature, which is a temperature of the simulated battery, a power supply device that supplys power to the simulated battery, and a control device that controls the power supply device, wherein the control device comprises a parameter receiving unit that receives an input profile indicating time-dependent change of a current, a voltage, or power applied to the actual battery as one of evaluation parameters, a resistance value calculation unit that calculates a resistance value of the actual battery, which changes over time, based on the simulated battery temperature and the input profile, and a power supply control unit that controls the power supply device using the resistance value calculated by the resistance value calculation unit.
The battery case evaluation system described in claim 1, wherein the control device further comprises an SOC calculation unit that calculates an SOC of the actual battery, which changes over time, based on the input profile, and 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.
The battery case evaluation system described in claim 2, wherein the parameter receiving unit receives a 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.
The battery case evaluation system described in either one of claim 1 through claim 3, wherein the parameter receiving unit receives, in addition to the input profile, at least one of an initial SOC of the actual battery or an SOH of the actual battery as the evaluation parameter.
The battery case evaluation system described in either one of claim 1 through claim 4, wherein the resistance value calculation unit has a conversion table for converting the evaluation parameter received by the parameter receiving unit into the resistance value, or a simulation model that outputs the resistance value using the evaluation parameter received by the parameter receiving unit.
The battery case evaluation system described in either one of claim 1 through claim 5, wherein the control device further comprises an entropy change calculation unit that calculates an entropy change generated accompanied by charging and discharging of the actual battery, and 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.
The battery case evaluation system described in claim 6 citing claim 2 or claim 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 the entropy change occurring in the actual battery.
The battery case evaluation system described in either one of claim 1 through claim 7, wherein the simulated battery comprises a heat generating element to which power is supplied from the power supply device, and a heat diffusing element that holds the heat generating element and that diffuses heat emitted by the heat generating element, and at least one of the heat generating element or the heat diffusing element is formed with a predetermined pattern that is capable of reproducing surface temperature distribution of the actual battery.
The battery case evaluation system described in claim 8, wherein the simulated battery has a cooling mechanism for cooling itself.
The battery case evaluation system described in claim 8 or claim 9, wherein the heat generating element or the heat diffusing element is formed with a predetermined dense and sparce pattern or a predetermined uneven pattern.
The battery case evaluation system described in either one of claim 8 through claim 10, wherein the pattern of the heat generating element or the heat diffusing element is obtained by applying a machine learning model to the surface temperature distribution of the actual battery.
The battery case evaluation system described in either one of claim 8 through claim 11, wherein at least one of the heat generating element or the heat diffusing element is formed with the predetermined pattern capable of reproducing the time-dependent change in the surface temperature of the actual battery.
A battery case evaluation program for evaluating thermal characteristics of a battery case constituting a battery pack or a component part of the battery case, comprising a simulated battery that is installed in the battery case for simulating thermal behavior of an actual battery which is a component part of the battery pack, a temperature detection device that detects a 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 making the control device produce functions as a parameter receiving unit that receives an input profile indicating the time-dependent change in a current, a voltage, or power supplied to the actual battery as one of the evaluation parameters, a resistance value calculation unit that calculates a resistance value of the actual battery, which changes over time, based on the simulated battery temperature and the input profile, and a power supply control unit that controls the power supply device using the resistance value calculated by the resistance value calculation unit.
A battery case evaluation method for evaluating thermal characteristics of a battery case constituting a battery pack or a component of the battery case, and that is used together with a battery case evaluation system comprising a simulated battery that is installed in the battery case for simulating thermal behavior of an actual battery which is a component part of the battery pack, a temperature detection device that detects a simulated battery temperature, which is a 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 comprising a step of causing the control device to receive an input profile indicating time-dependent change of a current, a voltage, or power supplied to the actual battery as one of evaluation parameters, a step of causing the control device to calculate a resistance value of the actual battery, which changes over time, based on the simulated battery temperature and the input profile, and a step of causing the control device to control the power supply device using the calculated resistance value.

Description

Technical field The present invention relates to a battery case evaluation system, a battery case evaluation program, and a battery case evaluation method. Background art For example, lithium-ion batteries installed in vehicles, etc., require control of their operating temperature during use due to reasons such as their narrow operating temperature range. To appropriately control the operating temperature of a lithium-ion battery, the heat exchange between the battery case that houses the battery and that controls the temperature of the battery and the battery that is housed in the battery case and/or the heat exchange between the interior and the exterior of the battery case when the battery is housed within it, is crucial. Therefore, understanding the thermal behavior of the battery is necessary for developing the battery case. However, during early stages of the battery case development, the battery itself is often being designed concurrently. This frequently results in insufficient quantities of actual batteries being available. Furthermore, battery case designers may not be thoroughly familiar with handling methods of actual batteries. Consequently, simulated batteries that mimic the thermal behavior of actual batteries are required. Therefore, conventionally, resistive elements such as metal plates or rods with internal resistance close to that of the battery have been used as simulated batteries. By applying a current with a predetermined profile to this simulated battery, the thermal behavior of the actual battery has been roughly simulated. However, actual batteries exhibit fluctuating resistance values in real time due to temperature changes during operation. Conventional methods completely ignored these resistance fluctuations, failing to accurately simulate the actual battery's thermal behavior. Consequently, it was impossible to accurately evaluate the thermal characteristics of the battery case or its components. Prior art documents Patent documents Patent document 1: Japanese Unexamined Patent Application Publication No. 2022-151635 Summary of the invention Problems to be solved by the invention Therefore, the present invention is intended to solve the above-mentioned problems. Its objective is to enable more accurate simulation of battery thermal behavior than conventional methods, thereby allowing more efficient evaluation of battery cases. Means to solve the problem Namely, the battery case evaluation system according to the present invention is a battery case evaluation system for evaluating thermal characteristics of a battery case constituting a battery pack or a component of the battery case. A simulated battery installed within the battery case for simulating thermal behavior of an actual battery, which is a component part of that battery pack; a temperature detection device for detecting a simulated battery temperature, which is a 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 comprises a parameter receiving unit that receives an input profile indicating time-dependent change in a current, or a voltage, or power supplied to the actual battery as one of evaluation parameters, a resistance value calculation unit that calculates a resistance value of the actual battery, which changes over time, based on the simulated battery temperature and the input profile, and a power supply control unit that controls the power supply device using the resistance value calculated by the resistance value calculation unit. According to this battery case evaluation system, the resistance value of the actual battery, which changes over time, is calculated based on the simulated battery temperature and the input profile. The power supply device is then controlled using this calculated resistance value. This allows the thermal behavior of the actual battery to be accurately simulated while considering the constantly fluctuating resistance value of the actual battery, enabling efficient evaluation of the battery case. Furthermore, using a simulated battery avoids the risk of ignition that could occur with an actual battery (e.g., ignition due to electrode damage from impact during handling of the actual battery or ignition that could occur if the battery is accidentally overcharged). The thermal behavior of the actual battery includes the exothermic behavior and/or the endothermic behavior of the actual battery. However, actual batteries exhibit fluctuating resistance values and a state of charge (hereinafter also referred to as an SOC) during operation. Conventional methods completely disregard these SOC fluctuations, failing to accurately simulate the thermal behavior of the actual batteries. Therefore, it is preferable that the control device further comprises an SOC calculation unit that calculates an SOC of the actual battery, which changes over time, based on the i