Determination device, determination method, and program

Abstract

To prevent deterioration of a lithium metal battery.SOLUTION: A determination device comprises: an acquisition unit that acquires the transition curve of the voltage of a lithium metal battery comprising a negative electrode including lithium; and a determination unit that determines recommendation suppression time for recommending suppression of charge and discharge of the lithium metal battery, on the basis of the rate of change in the voltage within a short time constant range corresponding to a range of a short time constant in the transition curve.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a determination device, a determination method, and a program. [Background technology]

[0002] In recent years, research and development has been conducted to contribute to energy efficiency so that more people can have access to affordable, reliable, sustainable, and advanced energy. Regarding this technology, lithium metal batteries, which use lithium metal as a negative electrode, have attracted attention as a secondary battery. A lithium metal battery includes a positive electrode, a negative electrode having a metallic lithium layer, and an electrolyte disposed between the positive electrode and the negative electrode. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2023 / 118960 [Patent Document 2] Japanese Patent Publication No. 2023-17581 [Patent Document 3] Japanese Patent Publication No. 2022-113377 Summary of the Invention [Problem to be solved by the invention]

[0004] Lithium-ion batteries, which do not contain lithium in the negative electrode, are robust in mitigating transient resistance increases that occur during repeated charge and discharge. However, lithium metal batteries are less robust against transient resistance increases, so there is a concern that they may permanently deteriorate if they are repeatedly charged and discharged. Therefore, it is desirable to suppress permanent deterioration by avoiding repeated continuous charge and discharge.

[0005] The present invention has been made in consideration of the above circumstances, and one of its objects is to suppress the deterioration of lithium metal batteries, thereby contributing to improved energy efficiency. [Means for solving the problem]

[0006] The determination device, the determination method, and the program according to the present invention employ the following configuration. (1): A determination device according to one embodiment of the present invention includes an acquisition unit that acquires a voltage relaxation curve of a lithium metal battery having a negative electrode containing lithium, and a determination unit that determines a recommended suppression time for recommending suppression of charging and discharging of the lithium metal battery based on the rate of change of voltage in a short time constant range corresponding to a range of short time constants in the relaxation curve.

[0007] (2) In the above aspect (1), the acquisition unit acquires the transition curve generated based on the charge / discharge history of the lithium metal battery.

[0008] (3): In the above aspect (1), when the rate of change is equal to or less than a specified value, the determining unit determines that the recommended suppression time is longer than when the rate of change exceeds the specified value.

[0009] (4): In the above aspect (1), when the rate of change is equal to or less than a specified value, the recommended suppression time is determined by referring to a suppression time control map in which the recommended suppression time is set longer than when the rate of change exceeds the specified value.

[0010] (5): In the above aspect (1), a switching unit is further provided that switches the control mode between a first control mode that controls the lithium metal battery and a second control mode that imposes a smaller load on the lithium metal battery than in the first control mode.

[0011] (6): In the above aspect (5), the present invention further includes a providing unit that provides a user with information regarding the recommended suppression time, and a receiving unit that receives a designation of the control mode by the user, and the switching unit switches the control mode based on the designation.

[0012] (7): In the above aspect (6), the information regarding the recommended suppression time includes the recommended suppression time.

[0013] (8): In the above aspect (1), the lithium metal battery is mounted on a vehicle.

[0014] (9): A determination method according to one embodiment of the present invention is a determination method in which a computer acquires a voltage relaxation curve of a lithium metal battery having a negative electrode containing lithium, and determines a recommended suppression time for recommending suppression of charging and discharging of the lithium metal battery based on the rate of change of voltage in a short time constant range corresponding to a range of short time constants of the relaxation curve.

[0015] (10): A program according to one embodiment of the present invention causes a computer to acquire a voltage relaxation curve of a lithium metal battery having a negative electrode containing lithium, and determine a recommended suppression time for recommending suppression of charging and discharging of the lithium metal battery based on a rate of change of voltage in a short time constant range corresponding to a range of short time constants of the relaxation curve. [Effects of the Invention]

[0016] According to the aspects (1) to (10), the deterioration of the lithium metal battery can be suppressed. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a diagram illustrating an example of the configuration of a vehicle M equipped with a determination device 100 according to an embodiment. [Figure 2] 1 is a diagram illustrating an example of the configuration of a determination device 100. FIG. [Figure 3]FIG. 10 is a diagram showing an example of a visualized downtime control map 122. [Figure 4] FIG. 2 is a diagram showing an example of a relaxation curve after charging and discharging the lithium metal battery 10. [Figure 5] FIG. 2 is a diagram illustrating an example of the configuration of an ECU 200. [Figure 6] 4 is a flowchart showing an example of processing by the determination device 100. [Figure 7] 4 is a flowchart showing an example of processing by the ECU 200. [Figure 8] FIG. 10 is a diagram showing an example of a display screen of the input / output interface 43 that displays recommended pause information. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, embodiments of a determination device, a determination method, and a program according to the present invention will be described with reference to the drawings.

[0019] FIG. 1 is a diagram showing an example of the configuration of a vehicle M equipped with a determination device 100 according to an embodiment. The determination device 100 according to an embodiment determines the degradation state of a lithium metal battery 10 equipped in the vehicle M. The lithium metal battery 10 has a negative electrode containing lithium. The lithium metal battery 10 is a secondary battery that can be charged and discharged.

[0020] In addition to the lithium metal battery 10, the vehicle M is equipped with electrical equipment 40, measuring equipment 50, and a control device 60. The electrical equipment 40 includes, for example, a traction motor 41, an air conditioning device 42, and an input / output interface 43. The measuring equipment 50 includes, for example, a voltage detector 51 and a current detector 52. The control device 60 includes, for example, a determination device 100 and an ECU (Electronic Control Unit) 200.

[0021] The lithium metal battery 10 is, for example, a semi-solid battery. The lithium metal battery 10 includes, for example, a positive electrode 11, a negative electrode 12, and an electrolyte 13. The positive electrode 11 includes, for example, a positive electrode current collector 11A and a positive electrode active material layer 11B. The positive electrode current collector 11A is made of, for example, a current collecting foil such as aluminum. The positive electrode active material layer 11B is made of, for example, a layer of lithium cobalt oxide.

[0022] The negative electrode 12 includes, for example, a negative electrode current collector 12A and a negative electrode active material layer 12B. The negative electrode current collector 12A is made of, for example, a current collecting foil such as copper. The negative electrode active material layer 12B is made of, for example, a metallic lithium layer. The electrolyte 13 is a semi-solid electrolyte containing lithium ions (Li+). The electrolyte 13 is partitioned into a positive electrode 11 side and a negative electrode 12 side by a separator 13S.

[0023] During discharge, when the lithium metal battery 10 supplies power to an electrical device 40 mounted on the vehicle M, lithium ions Li+ flow from the negative electrode active material layer 12B through the separator 13S to the positive electrode 11. Along with the flow of lithium ions Li+, electrons e flow from the negative electrode 12 through the circuit of the electrical device 40 to the positive electrode 11. Due to the flow of lithium ions Li+ and electrons e, a current flows from the positive electrode 11 to the negative electrode 12, discharging the lithium metal battery 10. In the negative electrode active material layer 12B, metallic lithium dissolves as the lithium metal battery 10 discharges.

[0024] The lithium metal battery 10 is charged by a charging facility 70 located outside the vehicle M. The charging facility 70 is installed, for example, at the home of the owner of the vehicle M or at a charging station. During charging, lithium ions Li+ flow from the positive electrode active material layer 11B through the separator 13S to the negative electrode 12 side.

[0025] Along with the flow of lithium ions Li+, electrons e flow from positive electrode 11 to 12 through charging equipment 80. The flow of lithium ions Li+ and electrons e causes a current to flow from negative electrode 12 to positive electrode 11, charging lithium metal battery 10. In negative electrode active material layer 12B, metallic lithium is deposited as lithium metal battery 10 is charged.

[0026] The traction motor 41 in the electrical equipment 40 is, for example, an electric motor. The output shaft of the traction motor 41 is connected to the input shaft of the drive-side reduction gear and applies driving force to wheels connected to the drive reduction mechanism. The air conditioner 42 is, for example, an air conditioner, and adjusts the temperature of air in the passenger compartment of the vehicle M. The input / output interface 43 is, for example, a touch panel. The touch panel is, for example, attached to an instrument panel in the passenger compartment.

[0027] The input / output interface 43 may be provided as a separate input interface and output interface. In this case, the input interface may be, for example, a button (switch) provided on the steering wheel or instrument panel, and the output interface may be, for example, a display.

[0028] The voltage detector 51 in the measuring device 50 detects the voltage value between the terminals of the lithium metal battery 10. The voltage detector 51 outputs the detected voltage value to the determination device 100 of the control device 60. The current detector 52 detects the current value of the current flowing from the positive electrode 11 side to the negative electrode 12 side of the lithium metal battery 10. The current detector 52 outputs the detected current value to the determination device 100.

[0029] 2 is a diagram illustrating an example of the configuration of the determination device 100. The determination device 100 includes, for example, a communication unit 110, a storage unit 120, and a processing unit 130. The communication unit 110 transmits and receives signals between the determination device 100 and an external device. For example, the communication unit 110 transmits a current supply signal generated by the processing unit 130 to the AC power supply 20. The communication unit 110 receives a current signal transmitted by a current detector 52. The transmission and reception performed by the communication unit 110 may be wired communication via wiring or wireless communication via a network.

[0030] The storage unit 120 is formed of, for example, a hard disk drive (HDD) or a flash memory. The storage unit 120 may be a drive device external to the control device 60. The storage unit 120 stores a charge / discharge history 121 and an downtime control map 122. The downtime control map 122 includes, for example, a first downtime control map 123 and a second downtime control map 124.

[0031] 3 is a diagram showing an example of a visualized pause time control map 122. A first pause time control map 123 and a second pause time control map 124 in the pause time control map 122 are both maps that indicate pause times according to the rate of change of voltage discharged by the lithium metal battery. Both the first pause time control map 123 and the second pause time control map 124 are maps in which the pause time becomes longer as the rate of change of voltage becomes larger. The pause time control map 122 is an example of a suppression time control map.

[0032] The processing unit 130 includes, for example, an acquisition unit 131, a determination unit 132, and a notification unit 133. These components are realized by, for example, a hardware processor such as a CPU (Central Processing Unit) executing a program (software). Some or all of these components may be realized by hardware (including circuitry) such as an LSI (Large Scale Integration), an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a GPU (Graphics Processing Unit), or may be realized by a combination of software and hardware.

[0033] The program may be stored in advance in a storage unit 120 (a storage device with a non-transitory storage medium) such as an HDD or flash memory, or may be stored in a removable storage medium (a non-transitory storage medium) such as a DVD or CD-ROM, and installed by inserting the storage medium into a drive device.

[0034] The acquisition unit 131 acquires the voltage value output by the voltage detector 51 and the current value output by the current detector 52. The acquisition unit 131 adds the acquired voltage value and current value to the charge / discharge history stored in the storage unit 120. The acquisition unit 131 updates the charge / discharge history 121 by adding the voltage value and current value.

[0035] The acquisition unit 131 acquires a charge / discharge request when charging / discharging is requested for the lithium metal battery 10, for example, based on the detection results of the voltage detector 51 and the current detector 52 and the operating status of the traction motor 41 and the air conditioner 42 transmitted by the ECU 200. When the acquisition unit 131 acquires a charge / discharge request, the acquisition unit 131 reads the charge / discharge history 121 stored in the storage unit 120, and generates and acquires a voltage relaxation curve for the lithium metal battery 10 based on the charge / discharge history 121. The charge / discharge history 121 includes information on the history of charging and discharging performed by the lithium metal battery 10. The relaxation curve is a curve that indicates the voltage discharged from the lithium metal battery 10 within a certain time period after the lithium metal battery 10 starts to charge / discharge.

[0036] FIG. 4 is a diagram showing an example of a transition curve after charging and discharging the lithium metal battery 10. For example, after charging and discharging are completed, the lithium metal battery 10 draws a transition curve in which the rate of change in voltage is large and the change in voltage decreases over time. The transition curve has a different shape for each individual lithium metal battery 10. The acquisition unit 131, for example, normalizes the multiple charge and discharge histories 121 stored in the storage unit 120 to generate and acquire the transition curve.

[0037] The determination unit 132 determines a recommended suppression time for recommending suppression of charging and discharging of the lithium metal battery 10 based on the rate of change of voltage in a short time constant range corresponding to a range of short time constants in the relaxation curve acquired by the acquisition unit 131. For example, the relaxation curve shown in FIG. 4 includes a short time constant range L1 corresponding to a range of short time constants and a long time constant range L2 corresponding to a range of long time constants. The short time constant range L1 is the range from time t0 to time t1, and the long time constant range L2 is the range from time t1 to time t2. The short time constant range L1 is a range of time constants that is shorter than the long time constant range L2.

[0038] The determination unit 132 calculates the rate of change of the voltage in the short time constant range L1 based on the transition curve shown in Fig. 4. Based on the calculated rate of change, the determination unit 132 determines a recommended rest time for recommending suppression of charging and discharging of the lithium metal battery 10, for example, rest. The recommended rest time is an example of a recommended suppression time.

[0039] For example, determination unit 132 determines whether the calculated rate of change is equal to or less than a preset specified value. When the calculated rate of change is equal to or less than the specified value, determination unit 132 determines the recommended pause time to be longer than when the rate of change exceeds the specified value. Specifically, when the calculated rate of change is equal to or less than the specified value, determination unit 132 determines the recommended pause time by referring to a second pause time control map in which the recommended pause time is set longer than the first pause time control map that is referenced when the rate of change exceeds the specified value.

[0040] The notification unit 133 notifies the ECU 200 of information on the recommended pause time determined by the determination unit 132 .

[0041] 5 is a diagram showing an example of the configuration of ECU 200. ECU 200 includes, for example, a driving control unit 210, an air conditioning control unit 220, a mode setting unit 230, a providing unit 240, a receiving unit 250, and a mode switching unit 260. ECU 200 is realized, for example, in the same way as processing unit 130 of determination device 100, by a hardware processor such as a CPU executing a program (software). ECU 200 may also be realized, for example, by other means similar to processing unit 130 of determination device 100.

[0042] The driving control unit 210 executes control for driving the vehicle M. The driving control unit 210 controls the driving motor 41 by transmitting a drive signal to the driving motor 41 based on, for example, an operation request signal based on the operation of an accelerator pedal or a brake pedal. The air conditioning control unit 220 controls the air conditioner 42 to adjust the temperature in the vehicle cabin.

[0043] The mode setting unit 230 sets a control mode for controlling the vehicle M including the lithium metal battery 10. For example, the mode setting unit 230 sets, as the control mode, either a normal mode used in normal situations or an eco mode in which the load on the lithium metal battery 10 is smaller than in the normal mode. The normal mode is an example of a first control mode. The eco mode is an example of a second control mode.

[0044] In normal mode, both the driving control unit 210 and the air conditioning control unit 220 perform normal control. In eco mode, the driving control unit 210 reduces the load on the lithium metal battery 10 by suppressing sudden acceleration / deceleration and sudden braking. In eco mode, the air conditioning control unit 220 reduces the load on the lithium metal battery 10 by setting the temperature higher than in normal mode and reducing the airflow.

[0045] The providing unit 240 detects the operating status of the traction motor 41 and the air conditioning unit 42 and transmits the detected status to the determination device 100. The providing unit 240 provides information related to the recommended suppression time to a user. For example, the providing unit 240 acquires a recommended rest time notified by the notification unit 133 in the processing unit 130 of the determination device 100. The providing unit 240 generates recommended rest information according to the acquired recommended rest time, transmits the generated information to the input / output interface 43, and displays the information on the input / output interface 43, thereby providing the recommended rest information to an occupant. The occupant is an example of a user.

[0046] The input / output interface 43 generates an image based on the transmitted recommended pause information and displays it on the display screen. The image displayed on the display screen includes a control mode designation switch. The input / output interface 43 generates switching information according to the control mode designation switch operated by the occupant of the vehicle M and transmits it to the ECU 200. The switching information includes information designating the control mode by the occupant.

[0047] The reception unit 250 receives and accepts the switching information transmitted by the input / output interface 43, thereby accepting the control mode designation by the occupant. The mode switching unit 260 recognizes the occupant's designation based on the switching information accepted by the reception unit 250. The mode switching unit 260 switches the control mode between the normal mode and the eco mode based on the recognized occupant's designation.

[0048] Next, the processing in the control device 60 of the embodiment will be described, including the processing in the determination device 100 and the processing in the ECU00. Fig. 6 is a flowchart showing an example of the processing in the determination device 100. In the determination device 100, first, the acquisition unit 131 determines whether or not a charge / discharge request has been acquired (step S101).

[0049] If it is determined that a charge / discharge request has not been acquired, the acquisition unit 131 repeats the process of step S101. If it is determined that a charge / discharge request has been acquired, the acquisition unit 131 refers to the charge / discharge history stored in the storage unit 120 (step S103). Next, the acquisition unit 131 generates a transition curve based on the acquired charge / discharge history (step S105).

[0050] Next, the determination unit 132 identifies the short time constant of the transition curve generated by the acquisition unit 131 (step S107). Next, the determination unit 132 calculates the rate of change of the voltage in the short time constant range L1 based on the identified short time constant, and determines whether the calculated rate of change is equal to or less than a specified value (step S109).

[0051] If it is determined that the calculated rate of change is equal to or less than the specified value, the determination unit 132 reads out the second pause time control map 124 (step S111) and sets a recommended pause time based on the second pause time control map 124 (step S113). On the other hand, if it is determined that the calculated rate of change exceeds the specified value (is not equal to or less than the specified value), the determination unit 132 reads out the first pause time control map 123 and sets a recommended pause time based on the first pause time control map 123 (step S115).

[0052] Next, the notification unit 133 transfers the recommended pause time set by the determination unit 132 to the ECU 200 (step S117). In this way, the determination device 100 ends the processing shown in Fig. 6. Next, the processing of the ECU 200 will be described. Fig. 7 is a flowchart showing an example of the processing of the ECU 200.

[0053] In ECU 200, mode setting unit 230 determines whether the recommended rest time notified by determination device 100 has been acquired (step S201). If it is determined that the recommended rest time has not been acquired, providing unit 240 repeats the process of step S201. If it is determined that the recommended rest time has been acquired, providing unit 240 determines whether the recommended rest time is currently being reached (step S203).

[0054] If providing unit 240 determines that the current time is not during the recommended pause time (that the current time is during the recommended pause time), ECU 200 ends the processing shown in Fig. 7. If determining that the current time is during the recommended pause time, providing unit 240 generates recommended pause information according to the acquired recommended pause time and transmits it to input / output interface 43 (step S205). At this time, providing unit 240 sets an answer wait time during which it waits for input / output interface 43 to transmit switching information as an answer.

[0055] The input / output interface 43 to which the recommended pause information has been transmitted displays the recommended pause information. Here, an image is shown when the mode setting unit 230 has set the control mode to normal mode. Fig. 8 is a diagram showing an example of a display screen of the input / output interface 43 displaying the recommended pause information. The input / output interface 43 displaying the recommended pause information displays a message image GA11 and a pause designation switch SW11 and a maintain designation switch SW12 as the mode designation switch SW10.

[0056] The message image GA11 displays the message "We recommend pausing charging and discharging" along with the message "(approximately 2 minutes)" indicating the remaining time of the recommended pause. By looking at the message image GA11, the occupant recognizes that control to reduce the load on the lithium metal battery 10 is recommended.

[0057] For example, the occupant can switch the control mode from normal mode to eco mode to reduce the load on the lithium metal battery 10. On the other hand, switching the control mode to eco mode may result in a drop in the output of the traction motor 41 and a decrease in the cooling power of the air conditioning device 42.

[0058] When the occupant wishes to switch to the eco mode that reduces the load on the lithium metal battery 10 in accordance with the recommendation of the determination device 100, the occupant operates the pause designation switch SW11 of the mode designation switch SW10. On the other hand, when the occupant wishes to maintain the normal mode despite the recommendation of the determination device 100, the occupant operates the maintain designation switch SW12 of the mode designation switch SW10. The input / output interface 43 generates switching information based on the occupant's operation of the mode designation switch SW10 and transmits it to the ECU 200.

[0059] In ECU 200, after providing unit 240 transmits the recommended pause information in step S203, receiving unit 250 receives the switching information transmitted by input / output interface 43 and determines whether or not the information has been received (step S207). When receiving unit 250 determines that the switching information has been received, if the received switching information is maintain execution information based on operation of maintain designation switch SW12, mode switching unit 260 maintains the normal mode set as the control mode (step S215). When the received switching information is switching execution information based on operation of pause designation switch SW11, mode switching unit 260 switches the normal mode set as the control mode to eco mode (step S211). Then, ECU 200 ends the processing shown in FIG. 8.

[0060] If it is determined in step S207 that switching information has not been received, the reception unit 250 determines whether or not the response waiting time has elapsed (step S213). If it is determined that the response waiting time has not elapsed, the reception unit 250 repeats the process of step S207. If it is determined that the response waiting time has elapsed, the mode switching unit 260 switches the control mode to the eco mode (step S215). Thereafter, the ECU 200 ends the process shown in FIG. 8.

[0061] The control device 60 of the embodiment generates and acquires the voltage relaxation polarity of the lithium metal battery 10 based on the charge / discharge history of the lithium metal battery 10, and determines the recommended suppression time based on the rate of change of the voltage in the short-time constant range of the relaxation curve. This makes it possible to suppress deterioration of the lithium metal battery 10 and extend the life of the lithium metal battery 10.

[0062] The above-described embodiment can be expressed as follows. a storage medium for storing computer-readable instructions; a processor connected to the storage medium; The processor executes the computer-readable instructions to: obtaining a voltage relaxation curve for a lithium metal battery having a negative electrode comprising lithium; determining a recommended suppression time for recommending suppression of charging and discharging of the lithium metal battery based on a rate of change of voltage in a short time constant range corresponding to a range of short time constants of the relaxation curve; Judgment device.

[0063] The above describes the form for carrying out the present invention using an embodiment, but the present invention is not limited to such an embodiment, and various modifications and substitutions can be made within the scope that does not deviate from the gist of the present invention. [Explanation of symbols]

[0064] 10. Lithium metal batteries 11 Positive electrode 12 Negative electrode 13 Electrolytes 13S Separator 20 AC power supply 40 Electrical Equipment 41 Travel motor 42 Air conditioner 43 Input / Output Interface 50 Measuring Instruments 51 Voltage detector 52 Current detector 60 Control device 100 Judgment device 110 Communications Department 120 Storage section 121 Charge / Discharge History 122 Downtime Control Map 123 First Downtime Control Map 124 Second Downtime Control Map 130 Processing section 131 Acquisition Department 132 Judgment section 133 Notification Department 210 Travel control unit 220 Air conditioning control unit 230 Mode setting section 240 Provision Department 250 Reception 260 Mode switching section M vehicle L1 Short time constant range L2 Long time constant range GA11 message image SW10 Mode selection switch SW11 Pause switch SW12 Maintenance switch

Claims

1. an acquisition unit that acquires a voltage relaxation curve of a lithium metal battery having a negative electrode containing lithium; a determination unit that determines a recommended suppression time for recommending suppression of charging and discharging of the lithium metal battery based on a rate of change of voltage in a short time constant range corresponding to a range of a short time constant of the relaxation curve, Judgment device.

2. the acquisition unit acquires the transition curve generated based on a charge / discharge history of the lithium metal battery. The determination device according to claim 1 .

3. the determination unit determines that the recommended suppression time is longer when the rate of change is equal to or less than a specified value than when the rate of change exceeds the specified value. The determination device according to claim 1 .

4. the determination unit determines the recommended suppression time by referring to a suppression time control map in which the recommended suppression time is set longer when the rate of change is equal to or less than a specified value than when the rate of change exceeds the specified value. The determination device according to claim 1 .

5. a switching unit that switches a control mode between a first control mode that controls the lithium metal battery and a second control mode that applies a smaller load to the lithium metal battery than in the first control mode; The determination device according to claim 1 .

6. a providing unit that provides information about the recommended suppression time to a user; a reception unit that receives a designation of the control mode by the user, The switching unit switches the control mode based on the designation. The determination device according to claim 5 .

7. the information about the recommended suppression time includes the recommended suppression time; The determination device according to claim 6.

8. The lithium metal battery is installed in a vehicle. The determination device according to claim 1 .

9. The computer obtaining a voltage relaxation curve for a lithium metal battery having a negative electrode comprising lithium; determining a recommended suppression time for recommending suppression of charging and discharging of the lithium metal battery based on a rate of change of voltage in a short time constant range corresponding to a range of short time constants of the relaxation curve; Judgment method.

10. On the computer, obtaining a voltage relaxation curve for a lithium metal battery having a negative electrode comprising lithium; determining a recommended suppression time for recommending suppression of charging and discharging of the lithium metal battery based on a rate of change of voltage in a short time constant range corresponding to a range of short time constants of the relaxation curve; program.

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