Evaluation system for secondary batteries

Abstract

This secondary battery evaluation system comprises: a battery pack (11) consisting of a plurality of secondary battery cells (111); a voltage detecting circuit (13) for detecting the voltage value across both ends of the battery pack (11); a current detecting circuit (12) for detecting the current value of the battery pack (11); a test secondary battery (190) consisting of at least one battery cell manufactured from the same materials as the secondary battery cells (111); and a test power supply circuit (19) for controlling charging and discharging of the test secondary battery (190). The test power supply circuit (19) simulates charging and discharging of the battery pack (11) by: setting a test charging voltage value and a test charging current value for the test secondary battery (190) on the basis of the voltage value across both ends of the battery pack (11) and the current value during charging, and charging the test secondary battery (190) using the test charging voltage value and the test charging current value; and setting a test discharging voltage value and a test discharging current value for the test secondary battery (190) on the basis of the voltage value across both ends of the battery pack (11) and the current value during discharging, and discharging the test secondary battery (190) using the test discharging voltage value and the test discharging current value. When measuring SOC-OCV data, the test power supply circuit (19) performs charging and discharging of the test secondary battery (190) independently of the drive of the battery pack (11) to acquire the SOC-OCV data of the test secondary battery (190).

Description

Technical Field

[0001] The present invention relates to a system for evaluating the degree of deterioration of a secondary battery.

Background Art

[0002] Patent Document 1 describes a battery state detection device. The battery state detection device described in Patent Document 1 uses a battery (secondary battery) that supplies power to a motor or the like of a vehicle as the battery to be evaluated for the degree of deterioration, and a battery for monitoring the degree of deterioration is connected in parallel to the battery to be evaluated for the degree of deterioration.

[0003] The battery state detection device described in Patent Document 1 detects the state of the battery to be evaluated using the monitoring battery.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the device of Patent Document 1, the monitoring battery also operates during the operation of the battery to be evaluated. Therefore, during the operation of the battery to be evaluated, static evaluation such as OCV deterioration analysis of the battery to be evaluated cannot be performed, and the degree of deterioration cannot be accurately evaluated.

[0006] Also, when performing static evaluation such as OCV deterioration analysis on the battery to be evaluated, a long time is required. Therefore, for example, it cannot be applied to a system that cannot stop operating, such as a UPS battery.

[0007] Therefore, an object of the present invention is to provide a secondary battery evaluation system that can accurately evaluate the degree of deterioration of a battery to be evaluated (secondary battery) without stopping the operation of the battery to be evaluated. [Means for solving the problem]

[0008] The secondary battery evaluation system of this invention comprises a battery pack composed of a plurality of secondary battery cells, a voltage detection circuit for detecting the voltage value across the battery pack, a current detection circuit for detecting the current value of the battery pack, a test secondary battery composed of at least one battery cell manufactured from the same material as the secondary battery cells, and a power supply circuit for controlling the charging and discharging of the test secondary battery.

[0009] The power supply circuit sets the test charging voltage and current values ​​for the test secondary battery based on the voltage and current values ​​across the battery pack during charging, charges the test secondary battery with the test charging voltage and current values, and sets the test discharge voltage and current values ​​for the test secondary battery based on the voltage and current values ​​across the battery pack during discharge, and discharges the test secondary battery with the test discharge voltage and current values ​​to simulate the charging and discharging of the battery pack. When measuring SOC-OCV data, the power supply circuit charges and discharges the test secondary battery independently of the battery pack's operation and acquires the SOC-OCV data of the test secondary battery.

[0010] In this configuration, the charging and discharging of the test secondary battery can be performed independently of the operation of the battery pack. This allows for static evaluation of the test secondary battery even while the battery pack is in operation. Furthermore, since the test secondary battery is manufactured from the same material as the secondary battery cells of the battery pack, if the degradation characteristics of the test secondary battery can be measured, the degradation characteristics of the battery pack can be indirectly and accurately determined. [Effects of the Invention]

[0011] This invention makes it possible to accurately evaluate the degree of degradation of a secondary battery without stopping its operation. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1 is a diagram showing an example of a power system in which the secondary battery to be evaluated is used in an embodiment of the present invention. [Figure 2] Figure 2 is a functional block diagram showing an example of a secondary battery charging and discharging system including a secondary battery evaluation system according to the first embodiment of the present invention. [Figure 3] Figure 3 is a perspective view showing one embodiment of a battery pack. [Figure 4] Figure 4 is a functional block diagram showing an example of a secondary battery charging and discharging system including a secondary battery evaluation system according to a second embodiment of the present invention. [Figure 5] Figure 5 is a functional block diagram showing an example of a secondary battery evaluation system according to a third embodiment of the present invention. [Figure 6] Figure 6 shows an example of a schematic configuration of an EV to which a secondary battery evaluation system has been applied. [Figure 7] Figure 7 is a functional block diagram showing an example of a battery module installed in an EV. [Figure 8] Figure 8 is a functional block diagram showing an example of the configuration of the test system. [Modes for carrying out the invention]

[0013] [First Embodiment] An evaluation system for a secondary battery according to the first embodiment of the present invention will be described with reference to the figures.

[0014] (Power systems that utilize rechargeable batteries) Figure 1 is a configuration diagram showing an example of a power system in which a secondary battery to be evaluated is used in an embodiment of the present invention. As shown in Figure 1, the power system 90 includes a battery module 10, a solar panel 20, a PCS 31 for storage batteries, a PCS 32 for solar power, a system control unit 40, a grid connection relay 50, a current sensor 60, and a utility load.

[0015] Note that the power system 90 is not limited to a system with only the load type of the operator load. As long as the secondary battery (storage battery) of the battery module 10 is driven (charged and discharged) almost continuously, the configuration of the present invention can be applied and will act effectively. Also, although the power system 90 includes the solar panel 20 and the solar PCS 32, these can be omitted.

[0016] The battery module 10 is connected to the storage battery PCS 31. The solar panel 20 is connected to the solar PCS 32. The storage battery PCS 31 and the solar PCS 32 are connected to the system connection relay 50. The system connection relay 50 is connected to the commercial power system. An electric current sensor 60 is arranged on the connection line between the system connection relay 50 and the commercial power system.

[0017] The battery module 10 is a so-called ESS (Energy Storage System) and includes a plurality of secondary battery cells 111. The plurality of secondary battery cells 111 are charged or discharged by charge and discharge control from the storage battery PCS 31. A more specific configuration of the battery module 10 will be described later.

[0018] The system control unit 40 controls the operations of the storage battery PCS 31 and the solar PCS 32 so as to supply the power of the office load with the power from the solar PCS 32 and the power from the battery module 10. For example, if the system control unit 40 can predict the power of the operator load and supply the power of the operator load with the power of solar power generation and the power of purchased electricity up to the contract upper limit, the system control unit 40 performs control to supply the power of solar power generation and the power of purchased electricity up to the contract upper limit to the operator load. At this time, the system control unit 40 controls the operation of the solar PCS 32 based on the current measured by the electric current sensor 60 so that no reverse power flow occurs in the commercial power system.

[0019] Also, if the system control unit 40 cannot supply the power of the operator load with the power of solar power generation and the power of purchased electricity up to the contract upper limit and the battery module 10 is sufficiently charged, the system control unit 40 instructs the storage battery PCS 31 to perform discharge control from the battery module 10.

[0020] Furthermore, the system control unit 40 instructs the battery PCS 31 to control charging of the battery module 10 if the power supply for the business operator can be covered by the power from solar power generation and the power purchased up to the contract limit, and if there is surplus power from solar power generation and there is capacity available to charge the battery module 10.

[0021] The PCS31 for the storage battery controls the charging and discharging of multiple secondary battery cells 111 of the battery module 10 based on instructions from the system control unit 40.

[0022] (Evaluation system for secondary batteries) Figure 2 is a functional block diagram showing an example of a secondary battery charge / discharge system including a secondary battery evaluation system according to the first embodiment of the present invention. As shown in Figure 2, the secondary battery charge / discharge system comprises a battery module 10 and a storage battery PCS 31.

[0023] The PCS31 for the storage battery includes a microcontroller 311 and a DC-DC converter 312. The battery module 10 includes a battery pack 11, a current detection circuit 12, a voltage detection circuit 13, a test power supply circuit 19, and a test secondary battery 190.

[0024] The battery pack 11 is constructed by connecting multiple secondary battery cells 111 in series and in parallel. Figure 3 is a perspective view showing one embodiment of the battery pack. The multiple secondary battery cells 111 are arranged in a two-dimensional configuration, for example as shown in Figure 3, to constitute the battery pack 11.

[0025] The positive and negative terminals of the battery pack 11 are connected to the DC-DC converter 312 of the PCS 31 for the storage battery.

[0026] The current detection circuit 12 is connected between the positive terminal of the battery pack 11 and the DC-DC converter 312. The output terminal of the current detection circuit 12 is connected to the microcontroller 311. This allows the microcontroller 311 to obtain the current value of the battery pack 11.

[0027] The voltage detection circuit 13 is connected between the positive and negative terminals of the battery pack 11. The output terminal of the voltage detection circuit 13 is connected to the microcontroller 311. This allows the microcontroller 311 to obtain the voltage value across the battery pack 11. The voltage detection circuit 13 may also be configured to individually detect the voltage of each of the multiple secondary battery cells in the battery pack and output the sum of these values ​​as the voltage across the battery pack 11.

[0028] The microcontroller 311 receives operational control from the system control unit 40 and performs charging and discharging control of the DC-DC converter 312. In this process, the microcontroller 311 performs charging and discharging control based on the current value from the current detection circuit 12 and the voltage value from the voltage detection circuit 13.

[0029] The test secondary battery 190 is manufactured from the same material as multiple secondary battery cells 111. In other words, the test secondary battery 190 is identical to one of the secondary battery cells 111. The test secondary battery 190 may be composed of multiple secondary battery cells 111, as long as the number of secondary battery cells 111 is less than the number of secondary battery cells 111 that make up the battery pack 11. However, a smaller number is preferable. This simplifies the construction of the test secondary battery 190, enabling miniaturization and cost reduction.

[0030] The positive and negative terminals of the test secondary battery 190 are connected to the test power supply circuit 19.

[0031] The test power supply circuit 19 includes a charging circuit and an electronic load. The test power supply circuit 19 controls the charging of the test secondary battery 190 using the charging circuit. The test power supply circuit 19 controls the discharge of the test secondary battery 190 using the electronic load.

[0032] The test power supply circuit 19 is connected to the microcontroller 311 and the measurement data transmission unit 18 of the battery PCS 31. The measurement data transmission unit 18 may be located inside or outside the battery module 10.

[0033] (Simulation of charging and discharging of battery pack 11) The test power supply circuit 19 obtains the charging conditions (charging current value, charging voltage value) of the battery pack 11 from the microcontroller 311. The test power supply circuit 19 sets the charging voltage value and charging current value per single cell of the multiple secondary battery cells 111 that make up the battery pack 11 to be the same as the test charging voltage value and test charging current value per single cell of the test secondary battery 190.

[0034] For example, the test charging voltage value is set by dividing the voltage across the battery pack 11 during charging by the number of secondary battery cells 111 connected in series in the battery pack 11.

[0035] For example, the test charging current value is set by dividing the current value of the battery pack 11 during charging by the number of secondary battery cells 111 connected in parallel in the battery pack 11.

[0036] The test power supply circuit 19 controls the charging of the test secondary battery 190 based on the test charging voltage value and the test charging current value.

[0037] The test power supply circuit 19 obtains the discharge conditions (discharge current value, discharge voltage value) of the battery pack 11 from the microcontroller 311. The test power supply circuit 19 sets the discharge voltage value and discharge current value of the multiple secondary battery cells 111 that make up the battery pack 11 to be the same as the test discharge voltage value and test discharge current value of the test secondary battery 190.

[0038] For example, the test discharge voltage value is set by dividing the voltage across the battery pack 11 during discharge by the number of secondary battery cells 111 connected in series in the battery pack 11.

[0039] For example, the test discharge current value is set by dividing the current value of the battery pack 11 during discharge by the number of parallel-connected secondary battery cells 111 in the battery pack 11.

[0040] The test power supply circuit 19 controls the discharge of the test secondary battery 190 based on the test discharge voltage value and the test discharge current value.

[0041] By performing this simulated charge and discharge, the secondary battery evaluation system of this embodiment can make the degradation level of the test secondary battery 190 the same as the degradation level of the secondary battery cells 111 that make up the battery pack 11.

[0042] (When measuring SOC-OCV data) When measuring SOC-OCV data, the test power supply circuit 19 temporarily stops simulating the charging and discharging of the battery pack 11 as described above.

[0043] The test power supply circuit 19 has pre-programmed SOC-OCV measurement conditions.

[0044] Prior to SOC-OCV measurement, the test power supply circuit 19 discharges the test secondary battery 190 to a completely discharged state (SOC 0%). Then, intermittent charging for SOC-OCV measurement is performed, and SOC-OCV data (charge capacity and open-circuit voltage) is measured until the battery is fully charged (SOC 100%). Specifically, the test secondary battery 190 is charged from a completely discharged state (SOC 0%) with a predetermined current for a predetermined time (e.g., 1C for 1 minute), followed by a relaxation time (e.g., 10 minutes) to allow the elevated terminal voltage to stabilize. The terminal voltage after equilibrium is then measured as OCV data, and this procedure is repeated until the battery is fully charged. In this way, SOC-OCV data showing how the OCV value changes along with the displacement of the SOC can be obtained.

[0045] The test power supply circuit 19 outputs the measured SOC-OCV data to the measurement data transmission unit 18. The measurement data transmission unit 18 transmits the SOC-OCV data to an external device for degradation analysis, etc.

[0046] As a result, the secondary battery evaluation system of this embodiment can acquire SOC-OCV data of the test secondary battery 190 without stopping the operation (charging and discharging) of the battery pack 11, and can perform OCV analysis of the test secondary battery 190.

[0047] In this case, as described above, the degree of degradation of the test secondary battery 190 accurately simulates the degree of degradation of the secondary battery cells 111 of the battery pack 11. Therefore, by performing OCV analysis on the test secondary battery 190, the OCV analysis of the secondary battery cells 111 of the battery pack 11 can be performed accurately. This allows for an accurate evaluation of the degree of degradation of the secondary battery cells 111 of the battery pack 11.

[0048] Once the measurement of the SOC-OCV data is complete, the test power supply circuit 19 obtains the charge status of the battery pack 11 from the microcontroller 311 and resumes the simulation of charging and discharging the battery pack 11 as described above. Then, when it is time for the next SOC-OCV data measurement, the test power supply circuit 19 performs the SOC-OCV data measurement as described above. The simulation of charging and discharging the battery pack 11 and the measurement of SOC-OCV data are repeated thereafter.

[0049] As a result, the secondary battery evaluation system of this embodiment can continuously and accurately evaluate the degree of degradation of the battery pack 11 (the secondary battery cells 111 of the battery pack 11).

[0050] Furthermore, in the above configuration, the test secondary battery 190 is located within the battery module 10, just like the battery pack 11. As a result, the operating environment of the test secondary battery 190 is the same as the operating environment (ambient temperature) of the battery pack 11. Therefore, the accuracy of simulating the degree of degradation of the secondary battery cells 111 of the battery pack 11 using the test secondary battery 190 is improved. Consequently, the secondary battery evaluation system of this embodiment can evaluate the degree of degradation of the battery pack 11 (the secondary battery cells 111 of the battery pack 11) with even greater accuracy.

[0051] [Second Embodiment] A secondary battery evaluation system according to a second embodiment of the present invention will be described with reference to the figures. Figure 4 is a functional block diagram showing an example of a secondary battery charging and discharging system including the secondary battery evaluation system according to the second embodiment of the present invention.

[0052] The secondary battery evaluation system according to the second embodiment differs from the secondary battery evaluation system according to the first embodiment in that it does not utilize the microcontroller 311 of the storage battery PCS31, whereas the second embodiment utilizes the microcontroller 311. The other components of the secondary battery evaluation system according to the second embodiment are the same as those of the secondary battery evaluation system according to the first embodiment, and the explanation of the similar parts will be omitted.

[0053] The secondary battery evaluation system includes a battery module 10A. The battery module 10A differs from the battery module 10 according to the first embodiment in the test power supply circuit 19A. Other components of the battery module 10A are the same as those of the battery module 10, and descriptions of similar components are omitted.

[0054] The test power supply circuit 19A is connected to the output terminals of the current detection circuit 12 and the output terminals of the voltage detection circuit 13. The test power supply circuit 19A directly obtains the current value of the battery pack 11 from the current detection circuit 12. The test power supply circuit 19A directly obtains the voltage value across the battery pack 11 from the voltage detection circuit 13.

[0055] As a result, the secondary battery evaluation system of this embodiment can accurately measure SOC-OCV data for evaluating the degree of degradation of the battery pack 11 (secondary battery cells 111 of the battery pack 11) using only the battery module 10A, without including the microcontroller 311 of the storage battery PCS31.

[0056] [Third Embodiment] A secondary battery evaluation system according to a third embodiment of the present invention will be described with reference to the figures. Figure 5 is a functional block diagram showing an example of a secondary battery evaluation system according to the third embodiment of the present invention.

[0057] The secondary battery evaluation system according to the third embodiment differs from the secondary battery evaluation system according to the second embodiment in that the test power supply circuit 19B, the test secondary battery 190, etc., are located in a different location from the battery module 10B. In the following, only the differences between the secondary battery evaluation system according to the third embodiment and the secondary battery evaluation system according to the second embodiment will be described, and the descriptions of similar parts will be omitted.

[0058] (The first location where the battery module 10B is to be placed) The battery module 10B includes a battery pack 11, a current detection circuit 12, a voltage detection circuit 13, and a temperature sensor 16. In other words, the battery module 10B does not include a test power supply circuit 19B or a test secondary battery 190.

[0059] The temperature sensor 16 detects the ambient temperature of the battery pack 11 and outputs it to the transmitter 17. The current detection circuit 12 outputs the current value of the battery pack 11 to the transmitter 17. The voltage detection circuit 13 outputs the voltage value of the battery pack 11 to the transmitter 17.

[0060] The transmitting unit 17 transmits the ambient temperature, current value, and voltage value to the receiving unit 194.

[0061] (Second location where the test secondary battery and test power supply circuit are placed) The receiving unit 194, the condition setting unit 195, the test power supply circuit 19B, the test secondary battery 190, and the measurement data transmission unit 18 are located in a different location from the battery module 10B. For example, these are located in a test site where users performing OCV analysis are present.

[0062] The test power supply circuit 19B and the test secondary battery 190 are placed inside the constant temperature bath THCH. A temperature controller 199 is installed in the constant temperature bath THCH. The temperature controller 199 adjusts the temperature of the constant temperature bath THCH.

[0063] The receiving unit 194 outputs the ambient temperature, current value, and voltage value to the condition setting unit 195. The condition setting unit 195 outputs the ambient temperature to the temperature controller 199 and outputs the current value and voltage value to the test power supply circuit 19B.

[0064] The temperature controller 199 adjusts the temperature of the constant temperature bath THCH so that it matches the ambient temperature it receives.

[0065] The test power supply circuit 19B simulates the charging and discharging of the battery pack 11 to the test secondary battery 190 based on the received current and voltage values. The test power supply circuit 19B also measures SOC-OCV data at predetermined timings.

[0066] As described above, this configuration allows for OCV analysis and degradation evaluation without placing the test secondary battery 190 near the battery pack 11 being evaluated. This makes it easy to entrust the evaluation to an OCV analysis specialist in a remote location. For example, a battery manufacturer can accurately evaluate the degradation of an ESS battery (battery pack 11) used at a customer's site using a system with the test secondary battery 190 located within the company, without having to visit the customer's site where the ESS is in operation.

[0067] Although the above description assumes a factory or similar environment, the secondary battery evaluation system of this application can also be applied to the evaluation of secondary batteries (EV batteries) such as those used in EVs (electric vehicles) that utilize electricity as driving energy.

[0068] Figure 6 shows an example of a schematic configuration of an EV to which a secondary battery evaluation system is applied. Figure 7 is a functional block diagram showing an example of a battery module mounted on an EV. Figure 8 is a functional block diagram showing an example of a test system configuration. Functional parts with the same configuration as those in the embodiments described above are denoted by the same reference numerals, and in the following, explanations of parts with the same reference numerals will be omitted.

[0069] As shown in Figure 6, the EV90C comprises an ECU 91, a DC-DC converter 92, an inverter 93, a drive motor 94, a charging port 95, a wireless device 96, and a battery module 10C.

[0070] As shown in Figure 7, the battery module 10C includes a battery pack 11, a current detection circuit 12, a voltage detection circuit 13, a temperature sensor 16, and a microcontroller 911.

[0071] The ECU91, DCDC converter92, inverter93, and the microcontroller911 of the battery module10C are connected to CAN. The ECU91 issues control commands to the DCDC converter92, inverter93, and battery module10C via CAN, thereby controlling the entire EV90C.

[0072] The DC-DC converter 92 is connected to the charging port 95 and then to the inverter 93. The inverter 93 is connected to the drive motor 93.

[0073] The DC-DC converter 92 converts the DC power supplied from the charging port 95 into the charging voltage and charging current of the battery pack 11 of the battery module 10C, thereby supplying charging power to the battery pack 11 of the battery module 10C.

[0074] Furthermore, the DC-DC converter 92 converts the DC power charged in the battery pack 11 into DC voltages for the inverter and supplies them to the inverter 93.

[0075] The inverter 93 converts the DC current and DC voltage supplied through the DC-DC converter 92 into predetermined AC voltage and AC current, and supplies them to the drive motor 94.

[0076] The wireless device 96 transmits the ambient temperature, current value, and voltage value obtained through the microcontroller 911 and ECU 91 to the wireless communication unit 194C, which is located in a constant temperature chamber THCH separate from the EV90C.

[0077] This makes it possible to measure SOC-OCV data using a constant temperature bath THCH as shown in the third embodiment described above.

[0078] <1> A battery pack consisting of multiple secondary battery cells, A voltage detection circuit for detecting the voltage value across both ends of the battery pack, A current detection circuit for detecting the current value of the battery pack, A test secondary battery comprising at least one battery cell manufactured from the same material as the aforementioned secondary battery cell, A power supply circuit for controlling the charging and discharging of the aforementioned test secondary battery, Equipped with, The aforementioned power supply circuit is Based on the voltage value across the battery pack and the current value during charging, a test charging voltage value and a test charging current value are set for the test secondary battery, and the test secondary battery is charged with the test charging voltage value and the test charging current value. Based on the voltage value across both ends and the current value during the discharge of the battery pack, a test discharge voltage value and a test discharge current value are set for the test secondary battery, and the charging and discharging of the battery pack is simulated by discharging the test secondary battery with the test discharge voltage value and the test discharge current value. When measuring SOC-OCV data, the charging and discharging of the test secondary battery is performed independently of the operation of the battery pack, and the SOC-OCV data of the test secondary battery is acquired. Evaluation system for secondary batteries.

[0079] <2> The aforementioned test secondary battery is located within a battery module that incorporates the aforementioned battery pack. <1> The evaluation system for secondary batteries described above.

[0080] <3> A temperature sensor for detecting the ambient temperature of the battery pack, A transmitting unit that transmits the voltage value across both ends, the current value, and the ambient temperature, A receiving unit that receives the voltage value across both ends, the current value, and the ambient temperature of the battery pack from the transmitting unit, A constant temperature bath and Equipped with, The battery pack, the voltage detection circuit, the current detection circuit, the temperature sensor, and the transmitting unit are arranged in the first location. The test secondary battery, the power supply circuit, the receiving unit, and the constant temperature bath are arranged in a second location different from the first location. The aforementioned test secondary battery is placed inside the constant temperature bath. The constant temperature bath is controlled to reproduce the ambient temperature of the battery pack. <1> or <2> The evaluation system for secondary batteries described above.

[0081] <4> The aforementioned battery pack is a battery for driving electric vehicles. <3> The evaluation system for secondary batteries described above. [Explanation of symbols]

[0082] 10, 10A, 10B, 10C: Battery Modules 11: Battery pack 12: Current detection circuit 13: Voltage detection circuit 16: Temperature sensor 17: Transmitter 18: Measurement data transmission unit 19, 19A, 19B: Test power supply circuits 20: Solar panels 31: PCS for storage battery 32: Solar PCS 40: System Control Unit 50: Grid-connected relay 60: Current sensor 90: Power Systems 90C:EV 91: ECU 92: DC-DC converter 93: Inverter 94: Drive motor 95: Charging port 96: Radio equipment 111: Secondary battery cell 190: Test secondary battery 194: Receiver 194C: Wireless Communication Department 195: Condition Setting Section 199: Temperature controller 311: Microcontroller 312: DC-DC converter 911: Microcontroller THCH: Constant temperature bath

Claims

1. A battery pack consisting of multiple secondary battery cells, A voltage detection circuit for detecting the voltage value across both ends of the battery pack, A current detection circuit for detecting the current value of the battery pack, A test secondary battery comprising at least one battery cell manufactured from the same material as the aforementioned secondary battery cell, A power supply circuit for controlling the charging and discharging of the aforementioned test secondary battery, Equipped with, The aforementioned power supply circuit is Based on the voltage value across the battery pack and the current value during charging, a test charging voltage value and a test charging current value are set for the test secondary battery, and the test secondary battery is charged with the test charging voltage value and the test charging current value. Based on the voltage value across both ends and the current value during the discharge of the battery pack, a test discharge voltage value and a test discharge current value are set for the test secondary battery, and the charging and discharging of the battery pack is simulated by discharging the test secondary battery with the test discharge voltage value and the test discharge current value. When measuring SOC-OCV data, the charging and discharging of the test secondary battery is performed independently of the operation of the battery pack, and the SOC-OCV data of the test secondary battery is acquired. Evaluation system for secondary batteries.

2. The aforementioned test secondary battery is located within a battery module that incorporates the aforementioned battery pack. The evaluation system for a secondary battery according to claim 1.

3. A temperature sensor for detecting the ambient temperature of the battery pack, A transmitting unit that transmits the voltage value across both ends, the current value, and the ambient temperature, A receiving unit that receives the voltage value across both ends, the current value, and the ambient temperature of the battery pack from the transmitting unit, A constant temperature bath and Equipped with, The battery pack, the voltage detection circuit, the current detection circuit, the temperature sensor, and the transmitting unit are arranged in the first location. The test secondary battery, the power supply circuit, the receiving unit, and the constant temperature bath are arranged in a second location different from the first location. The aforementioned test secondary battery is placed inside the constant temperature bath. The constant temperature bath is controlled to reproduce the ambient temperature of the battery pack. The evaluation system for a secondary battery according to claim 1.

4. The secondary battery evaluation system according to claim 3, wherein the battery pack is a battery for driving an electric vehicle.

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