Battery self-discharge characteristic testing method, device, equipment and medium

Abstract

The present invention discloses a battery self-discharge characteristic testing method, a battery self-discharge characteristic testing device, a battery self-discharge characteristic testing equipment, and a computer-readable storage medium, belonging to the technical field of battery testing. By performing two identical pulse charges on a battery to be tested in a static stable state and then allowing it to stand, the voltage change over time of the battery to be tested during the two pulse charging processes is determined. Based on the voltage change over time, the average self-discharge current of the battery to be tested when it is at rest after the first pulse charging is further determined, and the self-discharge characteristics of the battery to be tested are characterized by the average self-discharge current. Based on the precise voltage sampling during the two pulse charging and standing processes, the self-discharge current during the battery self-discharge process and the irrecoverable and recoverable self-discharge currents are evaluated, and the battery self-discharge characteristics obtained by the test are accurate and reliable.

Description

Technical Field

[0001] The present invention relates to the technical field of battery testing, and in particular to a battery self-discharge characteristic testing method, a battery self-discharge characteristic testing device, a battery self-discharge characteristic testing equipment, and a computer-readable storage medium. Background Art

[0002] Lithium batteries are widely used in electric transportation, portable electronic devices, and energy storage systems due to their outstanding advantages, such as high specific energy, low mass, zero memory, and zero pollution. However, in actual use, due to differences in the capacity and self-discharge characteristics of individual cells, the system capacity of multiple battery modules is often low. At the same time, as the number of charge and discharge cycles increases, the inconsistency between cells is further exacerbated, and the cycle life of the battery system is significantly reduced compared to the life of the individual cells. Therefore, in-depth research on the self-discharge rate of lithium-ion batteries is urgently needed for the efficient use of batteries. Self-discharge is the process by which the battery itself consumes its own charge. Self-discharge can be divided into two modes: recoverable self-discharge and irrecoverable self-discharge. This characteristic accompanies the entire life cycle of the battery.

[0003] The existing method for testing the irrecoverable and recoverable capacity of a battery during self-discharge is fixed: (1) calibrate the initial full-charge capacity of a brand-new battery; (2) place the battery at a specific temperature and time; (3) use CC (constant current)-CV (constant voltage) or CC discharge methods to detect the remaining charge in the capacitor. The difference between the remaining charge and the initial charge is the self-discharge charge of the battery under static conditions; (4) charge the battery to full charge after the residual charge test is completed. The difference between the fully charged charge and the fully charged charge of the new initial battery is the irrecoverable charge of the battery under static conditions; (5) subtract the irrecoverable charge from the total self-discharge charge to obtain the recoverable charge under static conditions.

[0004] The test process is fixed and complex because the self-discharge process of the battery is an internal physical and chemical process and cannot be directly measured by an external test system. Although this method can distinguish between chemical irreversible self-discharge and physical recoverable self-discharge, the accuracy of the charge or discharge test during the capacity calibration process will drastically affect the size of the two capacities. At the same time, the charge and discharge process will also cause additional physical and chemical self-discharge, that is, the test results are not all accurate capacities of chemical and physical self-discharge under static conditions. Admittedly, there is currently no method in the industry that can detect and distinguish between irreversible and recoverable self-discharge capacity or current under specific battery conditions. The existing methods all test the overall self-discharge current of the battery or perform charge and discharge calibration, which cannot accurately distinguish between irreversible and recoverable self-discharge currents. Summary of the Invention

[0005] The main purpose of the present invention is to provide a battery self-discharge characteristic testing method, a battery self-discharge characteristic testing device, a battery self-discharge characteristic testing equipment and a computer-readable storage medium, aiming to solve the technical problem in the prior art that it is difficult to accurately determine the battery self-discharge characteristics.

[0006] To achieve the above object, the present invention provides a method for testing battery self-discharge characteristics, comprising the following steps:

[0007] Obtaining an initial open circuit voltage of the battery under test in a static stable state, performing a first pulse charge on the battery under test and allowing it to stand;

[0008] When the open circuit voltage of the battery under test drops to the initial open circuit voltage after the first pulse charging, performing a second pulse charging on the battery under test that is the same as the first pulse charging and allowing the battery to stand;

[0009] When the open circuit voltage of the battery to be tested drops to the initial open circuit voltage after the second pulse charging, the average self-discharge current of the battery to be tested when it is at rest after the first pulse charging is determined based on the change in the voltage of the battery to be tested over time during the two pulse charging processes. The average self-discharge current includes the average irrecoverable self-discharge current and the average recoverable self-discharge current.

[0010] Optionally, the step of determining the average self-discharge current of the battery under test when it is at rest after the first pulse charging based on the change of the voltage of the battery under test over time during the two pulse charging processes includes:

[0011] Determine the charging charge amount of pulse charging;

[0012] Based on the change of the voltage of the battery under test over time during the two pulse charging processes, determining a curve function of the linear voltage decrease during the two rest times;

[0013] Based on the charging charge, the initial open circuit voltage and the curve function, an average self-discharge current of the battery to be tested when it is at rest after the first pulse charging is determined.

[0014] Optionally, the step of determining the amount of charge for pulse charging includes:

[0015] The charge amount of the pulse charging is determined according to the average self-discharge current of the battery to be tested when it is at rest after the first pulse charging and the first resting time.

[0016] Optionally, the step of determining a curve function of a linear voltage drop during two rest periods based on the change in voltage of the battery under test over time during the two pulse charging processes includes:

[0017] According to the start time of the linear decrease in the open-circuit voltage of the battery to be tested when the battery to be tested is left at rest after the first pulse charging and the second pulse charging, the start voltage at the start time, the end time of the linear decrease in the open-circuit voltage of the battery to be tested, and the end voltage at the end time, a first curve function for the linear decrease in voltage during the first rest time and a second curve function for the linear decrease in voltage during the second rest time are determined.

[0018] Optionally, the step of determining the average self-discharge current of the battery under test when it is at rest after the first pulse charging based on the charging charge, the initial open circuit voltage and the curve function includes:

[0019] determining a first theoretical open-circuit voltage at the beginning of a first rest period based on the first curve function;

[0020] determining a second theoretical open-circuit voltage at the beginning of the second rest period based on the second curve function;

[0021] An average self-discharge current of the battery under test when it is at rest after the first pulse charging is determined based on the charging charge, the initial open circuit voltage, the first theoretical open circuit voltage, and the second theoretical open circuit voltage.

[0022] Optionally, the step of determining an average self-discharge current of the battery under test when it is at rest after the first pulse charging based on the charging charge, the initial open-circuit voltage, the first theoretical open-circuit voltage, and the second theoretical open-circuit voltage includes:

[0023] Determining a self-discharge charge of the battery under test when it is at rest after the first pulse charging based on the charged charge, the initial open circuit voltage, the first theoretical open circuit voltage, and the second theoretical open circuit voltage;

[0024] Based on the self-discharge charge and the first rest time, an average self-discharge current of the battery to be tested is determined.

[0025] Optionally, the self-discharge charge of the battery to be tested includes an irrecoverable self-discharge charge and a recoverable self-discharge charge. The step of determining the irrecoverable self-discharge charge of the battery to be tested when it is at rest after the first pulse charging based on the charged charge, the initial open-circuit voltage, the first theoretical open-circuit voltage, and the second theoretical open-circuit voltage includes:

[0026] determining a first voltage difference between the first theoretical open circuit voltage and the initial open circuit voltage;

[0027] determining a second voltage difference between the second theoretical open circuit voltage and the initial open circuit voltage;

[0028] determining an irrecoverable self-discharge charge amount based on a difference between the first voltage difference and the second voltage difference, the second voltage difference, and the charged charge amount;

[0029] Optionally, the step of determining the recoverable self-discharge charge of the battery under test when it is at rest after the first pulse charging based on the charged charge, the initial open circuit voltage, the first theoretical open circuit voltage, and the second theoretical open circuit voltage includes:

[0030] A recoverable self-discharge charge amount is determined based on the first voltage difference, the second voltage difference, and the charged charge amount.

[0031] Optionally, the average self-discharge current of the battery to be tested includes an irrecoverable self-discharge average current and a recoverable self-discharge average current, and the step of determining the average self-discharge current of the battery to be tested based on the self-discharge charge and the first rest time includes:

[0032] Determining an average irrecoverable self-discharge current of the battery to be tested based on the irrecoverable self-discharge charge and the first rest time;

[0033] Determining a recoverable self-discharge average current of the battery to be tested based on the recoverable self-discharge charge and the first rest time;

[0034] The average self-discharge current of the battery to be tested is determined based on the average irrecoverable self-discharge current and the average recoverable self-discharge current.

[0035] In addition, to achieve the above-mentioned object, the present invention further provides a battery self-discharge characteristic testing device, wherein the battery self-discharge characteristic testing device is used to:

[0036] A first charging and resting module is used to obtain an initial open circuit voltage of the battery under test in a static and stable state, perform a first pulse charging on the battery under test, and rest the battery;

[0037] a second charging and resting module, configured to perform a second pulse charging, which is the same as the first pulse charging, on the battery to be tested and rest the battery to be tested when the open circuit voltage of the battery to be tested drops to the initial open circuit voltage after the first pulse charging;

[0038] a calculation module for determining, when the open-circuit voltage of the battery under test drops to the initial open-circuit voltage after the second pulse charging, an average self-discharge current of the battery under test when it is at rest after the first pulse charging based on the change in the voltage of the battery under test over time during the two pulse charging processes, wherein the average self-discharge current includes an average irrecoverable self-discharge current and an average recoverable self-discharge current.

[0039] In addition, to achieve the above-mentioned purpose, the present invention also provides a battery self-discharge characteristic testing device, which includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the computer program is configured to implement the steps of the battery self-discharge characteristic testing method as described above.

[0040] In addition, to achieve the above-mentioned purpose, the present invention further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the battery self-discharge characteristic testing method described above are implemented.

[0041] Embodiments of the present invention provide a battery self-discharge characteristic testing method, a battery self-discharge characteristic testing device, a battery self-discharge characteristic testing equipment, and a computer-readable storage medium. The methods include obtaining an initial open-circuit voltage of a battery to be tested in a static stable state, performing a first pulse charge on the battery to be tested and allowing the battery to be tested to rest; when the open-circuit voltage of the battery to be tested drops to the initial open-circuit voltage after the first pulse charge, performing a second pulse charge identical to the first pulse charge on the battery to be tested and allowing the battery to rest; and when the open-circuit voltage of the battery to be tested drops to the initial open-circuit voltage after the second pulse charge, determining an average self-discharge current of the battery to be tested when the battery is at rest after the first pulse charge based on a change in the voltage of the battery to be tested over time during the two pulse charging processes. The average self-discharge current includes an average irrecoverable self-discharge current and an average recoverable self-discharge current.

[0042] By performing two identical pulse charges on a battery in a stable static state and then allowing it to rest, the voltage variation over time during the two pulse charging processes is determined. Based on this voltage variation over time, the average self-discharge current, as well as the irrecoverable and recoverable self-discharge currents of the battery at rest after the first pulse charge, are further determined. The irrecoverable and recoverable self-discharge average currents are used to characterize the self-discharge characteristics of the battery. Accurate voltage sampling during the two pulse charging and resting processes enables the evaluation of the battery's self-discharge characteristics, resulting in accurate and reliable self-discharge characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a schematic diagram of the structure of the operating equipment of the hardware operating environment involved in the embodiment of the present invention;

[0044] Figure 2 This is a flow chart of an embodiment of a method for testing battery self-discharge characteristics according to the present invention;

[0045] Figure 3This is a schematic diagram of an ideal equivalent circuit model of a lithium battery according to an embodiment of a method for testing battery self-discharge characteristics of the present invention;

[0046] Figure 4 This is a schematic diagram of the open circuit voltage change of a stable lithium battery after charging according to an embodiment of a method for testing battery self-discharge characteristics of the present invention;

[0047] Figure 5 This is a schematic diagram of the change in open circuit voltage of a battery under test after two pulse charges in accordance with an embodiment of a method for testing battery self-discharge characteristics of the present invention;

[0048] Figure 6 This is a schematic diagram of an application of an embodiment of a method for testing battery self-discharge characteristics of the present invention;

[0049] Figure 7 It is a schematic diagram of a device according to an embodiment of a method for testing battery self-discharge characteristics of the present invention.

[0050] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0051] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0052] Reference Figure 1 , Figure 1 This is a schematic diagram of the structure of the operating equipment of the hardware operating environment involved in the embodiment of the present invention.

[0053] like Figure 1 As shown, the operating device may include: a processor 1001, such as a central processing unit (CPU), a communication bus 1002, a user interface 1003, a network interface 1004, and a memory 1005. The communication bus 1002 is used to realize the connection and communication between these components. The user interface 1003 may include a display screen (Disp l ay) and an input unit such as a keyboard (Keyboard). Optionally, the user interface 1003 may also include a standard wired interface and a wireless interface. The network interface 1004 may optionally include a standard wired interface and a wireless interface (such as a wireless fidelity (WI re less-Fi de l ity, WI-FI) interface). The memory 1005 may be a high-speed random access memory (Random Access Memory, RAM) memory, or a stable non-volatile memory (Non-Volume ile Memory, NVM), such as a disk memory. The memory 1005 may also be a storage device independent of the aforementioned processor 1001.

[0054] Those skilled in the art will understand that Figure 1 The structure shown in the figure does not constitute a limitation on the operating device, and may include more or fewer components than shown in the figure, or combine certain components, or arrange the components differently.

[0055] like Figure 1 As shown, the memory 1005 as a storage medium may include an operating system, a data storage module, a network communication module, a user interface module and a computer program.

[0056] exist Figure 1 In the operating device shown, the network interface 1004 is mainly used for data communication with other devices; the user interface 1003 is mainly used for data interaction with the user; the processor 1001 and the memory 1005 in the operating device of the present invention can be set in the operating device, and the operating device calls the computer program stored in the memory 1005 through the processor 1001 and performs the following operations:

[0057] Obtaining an initial open circuit voltage of the battery under test in a static stable state, performing a first pulse charge on the battery under test and allowing it to stand;

[0058] When the open circuit voltage of the battery under test drops to the initial open circuit voltage after the first pulse charging, performing a second pulse charging on the battery under test that is the same as the first pulse charging and allowing the battery to stand;

[0059] When the open circuit voltage of the battery to be tested drops to the initial open circuit voltage after the second pulse charging, the average self-discharge current of the battery to be tested when it is at rest after the first pulse charging is determined based on the change in the voltage of the battery to be tested over time during the two pulse charging processes. The average self-discharge current includes the average irrecoverable self-discharge current and the average recoverable self-discharge current.

[0060] Furthermore, the processor 1001 may call a computer program stored in the memory 1005 and perform the following operations:

[0061] The step of determining the average self-discharge current of the battery under test when it is at rest after the first pulse charging based on the change of the voltage of the battery under test over time during the two pulse charging processes includes:

[0062] Determine the charging charge amount of pulse charging;

[0063] Based on the change of the voltage of the battery under test over time during the two pulse charging processes, determining a curve function of the linear voltage decrease during the two rest times;

[0064] Based on the charging charge, the initial open circuit voltage and the curve function, an average self-discharge current of the battery under test when it is at rest after the first pulse charging is determined.

[0065] Furthermore, the processor 1001 may call a computer program stored in the memory 1005 and perform the following operations:

[0066] The step of determining the amount of charge for pulse charging comprises:

[0067] The charge amount of the pulse charging is determined according to the average self-discharge current of the battery to be tested when it is at rest after the first pulse charging and the first resting time.

[0068] Furthermore, the processor 1001 may call a computer program stored in the memory 1005 and perform the following operations:

[0069] The step of determining a curve function of a linear voltage drop during two rest periods based on the change of the voltage of the battery under test over time during the two pulse charging processes includes:

[0070] According to the start time of the linear decrease in the open-circuit voltage of the battery to be tested when the battery to be tested is left at rest after the first pulse charging and the second pulse charging, the start voltage at the start time, the end time of the linear decrease in the open-circuit voltage of the battery to be tested, and the end voltage at the end time, a first curve function for the linear decrease in voltage during the first rest time and a second curve function for the linear decrease in voltage during the second rest time are determined.

[0071] Furthermore, the processor 1001 may call a computer program stored in the memory 1005 and perform the following operations:

[0072] The step of determining the average self-discharge current of the battery under test when it is at rest after the first pulse charging based on the charging charge, the initial open circuit voltage and the curve function includes:

[0073] determining a first theoretical open-circuit voltage at the beginning of a first rest period based on the first curve function;

[0074] determining a second theoretical open-circuit voltage at the beginning of the second rest period based on the second curve function;

[0075] An average self-discharge current of the battery under test when it is at rest after the first pulse charging is determined based on the charging charge, the initial open circuit voltage, the first theoretical open circuit voltage, and the second theoretical open circuit voltage.

[0076] Furthermore, the processor 1001 may call a computer program stored in the memory 1005 and perform the following operations:

[0077] The step of determining the self-discharge average current of the battery to be tested when it is at rest after the first pulse charging based on the charging charge, the initial open circuit voltage, the first theoretical open circuit voltage, and the second theoretical open circuit voltage includes:

[0078] Determining a self-discharge charge of the battery under test when it is at rest after the first pulse charging based on the charged charge, the initial open circuit voltage, the first theoretical open circuit voltage, and the second theoretical open circuit voltage;

[0079] Based on the self-discharge charge and the first rest time, an average self-discharge current of the battery to be tested is determined.

[0080] Furthermore, the processor 1001 may call a computer program stored in the memory 1005 and perform the following operations:

[0081] The self-discharge charge of the battery to be tested includes an irrecoverable self-discharge charge and a recoverable self-discharge charge. The step of determining the irrecoverable self-discharge charge of the battery to be tested when it is at rest after the first pulse charging based on the charged charge, the initial open circuit voltage, the first theoretical open circuit voltage, and the second theoretical open circuit voltage comprises:

[0082] determining a first voltage difference between the first theoretical open circuit voltage and the initial open circuit voltage;

[0083] determining a second voltage difference between the second theoretical open circuit voltage and the initial open circuit voltage;

[0084] An irrecoverable self-discharge charge amount is determined based on a difference between the first voltage difference and the second voltage difference, the second voltage difference, and the charged charge amount.

[0085] Furthermore, the processor 1001 may call a computer program stored in the memory 1005 and perform the following operations:

[0086] The step of determining the recoverable self-discharge charge of the battery under test when it is at rest after the first pulse charging based on the charged charge, the initial open circuit voltage, the first theoretical open circuit voltage, and the second theoretical open circuit voltage comprises:

[0087] A recoverable self-discharge charge amount is determined based on the first voltage difference, the second voltage difference, and the charged charge amount.

[0088] Furthermore, the processor 1001 may call a computer program stored in the memory 1005 and perform the following operations:

[0089] The average self-discharge current of the battery to be tested includes an irrecoverable self-discharge average current and a recoverable self-discharge average current. The step of determining the average self-discharge current of the battery to be tested based on the self-discharge charge and the first rest time comprises:

[0090] Determining an average irrecoverable self-discharge current of the battery to be tested based on the irrecoverable self-discharge charge and the first rest time;

[0091] Determining a recoverable self-discharge average current of the battery to be tested based on the recoverable self-discharge charge and the first rest time;

[0092] The average self-discharge current of the battery to be tested is determined based on the average irrecoverable self-discharge current and the average recoverable self-discharge current.

[0093] Reference Figure 4 , Figure 4 The figure is a flow chart of an embodiment of a method for testing the self-discharge characteristics of a battery according to the present invention. The embodiment of the present invention provides a method for testing the self-discharge characteristics of a battery. In this embodiment, the method for testing the self-discharge characteristics of a battery comprises the following steps:

[0094] Recoverable self-discharge is the physical process of self-discharge between the positive and negative electrodes of a battery. This self-discharge current is a micro-discharge of the battery's internal insulating materials under conditions of a positive and negative voltage differential. While this process can cause a decrease in the battery's overall charge, it can generally be restored to its original full charge by recharging. However, unlike physical self-discharge, chemical self-discharge, or irreversible self-discharge, is a process of capacity reduction caused by irreversible chemical reactions in the battery's active materials. This phenomenon cannot be restored to its original full charge by recharging. Since irreversible and recoverable self-discharge correspond to internal chemical reactions and physical discharge processes, respectively, and occur simultaneously when the battery is at rest or in operation, determining the key characteristics of a battery's usable capacity, calendar life, and reliability requires the ability to effectively separate the irreversible and recoverable self-discharge characteristics from those of the battery's overall self-discharge, thereby effectively characterizing both the physical and irreversible chemical characteristics of the battery.

[0095] Reference Figure 3 , V is the open circuit voltage determined by the battery electrochemical system, Rs is the ohmic impedance of the battery, Rct and CPE are the charge transfer resistance and capacitance of the electrode-electrolyte interface of the battery, and W is the Warburg impedance, which is the diffusion impedance in the electrochemical reaction and represents the solid diffusion impedance of ions.

[0096] Reference Figure 4Figure 2 shows the evolution of the open-circuit voltage of a lithium battery after a pulse charge current. After the pulse charge current ends, the open-circuit voltage drops rapidly due to Rs, a process known as the voltage dip. Subsequently, due to the double-layer effect at the electrode interface, the open-circuit voltage undergoes a rapid exponential decline, typically lasting on the order of milliseconds. After this initial rapid voltage change, the open-circuit voltage decreases very slowly due to the slow diffusion of active materials within the battery, with a trend similar to an exponential decline. Over time, the open-circuit current generally exhibits a linear decline due to the battery's self-discharge process. During these four stages, it can be assumed that the double-layer effect and diffusion effects do not affect the battery's stable charge capacity. The capacitance decay is solely related to the battery's self-discharge process, specifically the linear self-discharge phase of the open-circuit voltage. Battery self-discharge is a constant process, occurring even during the double-layer and diffusion effect phases. Therefore, by extending the curve of the stable linear decline in battery voltage, we can derive the theoretical stable open-circuit voltage of a battery after pulse charging, accounting only for the self-discharge process. Therefore, in this embodiment, the battery to be tested is a battery that complies with the double layer effect and the diffusion effect, and only a lithium battery is used as an example for description.

[0097] At the same time, it is important to note that the irreversible self-discharge process of lithium batteries is the process of irreversible loss of their internal active substances. That is to say, after a battery is charged and left to stand, when the charge is consumed, due to the damage to the irreversible active substances, its voltage value will be higher than the stable voltage of the first pulse charge after the same capacity pulse charge. If the stable voltage of the battery after the second pulse charge is to be maintained at the same level as the stable voltage of the first pulse charge, the charge of the second pulse charge needs to be reduced (this operation is not actually performed in this embodiment). The reduced charge amount is the permanent capacity loss of the battery caused by irreversible self-discharge.

[0098] Step S10: obtaining an initial open circuit voltage of the battery under test in a static stable state, performing a first pulse charge on the battery under test and allowing it to stand;

[0099] Reference Figure 5 The initial open circuit voltage of the battery under test in a static stable state is the voltage Voc_0 at time t1. The battery under test is pulse charged for the first time at time t1, and the battery under test is placed in a static state at time t2.

[0100] Step S20: When the open circuit voltage of the battery under test drops to the initial open circuit voltage after the first pulse charging, the battery under test is subjected to a second pulse charging process identical to the first pulse charging process and allowed to stand;

[0101] At time t3, when the open-circuit voltage of the battery under test drops to the initial open-circuit voltage after the first pulse charging, the battery under test is subjected to a second pulse charging identical to the first pulse charging. At time t4, the battery under test is allowed to rest. The second pulse charging identical to the first pulse charging means that the first pulse charging and the second pulse charging have the same charge amount.

[0102] Step S30: When the open circuit voltage of the battery to be tested drops to the initial open circuit voltage after the second pulse charging, the average self-discharge current of the battery to be tested when it is at rest after the first pulse charging is determined based on the change in the voltage of the battery to be tested over time during the two pulse charging processes. The average self-discharge current includes the average irrecoverable self-discharge current and the average recoverable self-discharge current.

[0103] At time t5, when the open-circuit voltage of the battery under test drops to the initial open-circuit voltage after the second pulse charge, the self-discharge characteristic test of the battery under test is stopped. Based on the change in the voltage of the battery under test over time during the two pulse charge processes, the average irrecoverable and recoverable self-discharge currents of the battery under test during the rest period after the first pulse charge are determined. The self-discharge circuit characteristics are the respective proportions and absolute magnitudes of the average irrecoverable self-discharge current and the average recoverable self-discharge current. Thus, by performing two pulse charges and rest periods, the average irrecoverable self-discharge current and the average recoverable self-discharge current within the average self-discharge current during the rest period after the first pulse charge are separated and obtained.

[0104] Reference Figure 6In one embodiment of the present invention, (1) the battery to be tested, which is at rest and stable, is placed in an incubator, the incubator temperature is set and the battery to be tested is allowed to rest. After the incubator and battery temperature are stable, the initial open circuit voltage of the battery is accurately tested. The incubator temperature is maintained constant throughout the process. (2) The battery is pulse charged, and the charging current and time of the process are recorded in detail to determine the charging charge. The charging current does not exceed 0.1C of the battery, and the total charging charge does not exceed 1 / 1000 of the total capacity of the battery. In principle, it is a pulse current, and the pulse form is not limited, as long as the charge can be accurately tested. However, there is no requirement for the charging form, and pulse constant current and pulse constant voltage are both acceptable. Thereafter, the rest process of the battery to be tested is started. The voltage and open circuit voltage of the battery during the charging and rest process are accurately monitored. (3) After the open circuit voltage of the battery slowly drops to its initial open circuit voltage, the battery to be tested is pulse charged again in the same manner as in the first pulse charging and allowed to rest. Record the open circuit voltage of the second pulse charging process and the subsequent resting of the battery. (4) After the static voltage of the battery under test drops to the initial open circuit voltage after the second pulse charge, stop the test. Take out the battery and place it at room temperature until it stabilizes. (5) Using the change of voltage over time during the two pulse charging processes, solve in detail the curve function of the linear voltage drop during the two static times, and then solve the irrecoverable and recoverable self-discharge average current of the battery when it is at rest after the first pulse charge. Preferably, the charging process is a narrow pulse, and the charging start speed of the charging equipment should not be too fast, otherwise it may cause the battery instantaneous voltage to overshoot. In principle, it is only necessary to ensure that the total amount of charge charged into the battery during charging is accurately obtained, and the specific charging form is not limited.

[0105] In this embodiment, the initial open-circuit voltage of the battery to be tested in a static stable state is obtained, and the battery to be tested is subjected to a first pulse charge and allowed to stand; when the open-circuit voltage of the battery to be tested drops to the initial open-circuit voltage after the first pulse charge, the battery to be tested is subjected to a second pulse charge identical to the first pulse charge and allowed to stand; when the open-circuit voltage of the battery to be tested drops to the initial open-circuit voltage after the second pulse charge, the average self-discharge current of the battery to be tested when at rest after the first pulse charge is determined based on the change in the voltage of the battery to be tested over time during the two pulse charging processes, where the average self-discharge current includes an average irrecoverable self-discharge current and an average recoverable self-discharge current.

[0106] By performing two identical pulse charges on a battery in a stable static state and then allowing it to rest, the voltage variation over time during the two pulse charging processes is determined. Based on this voltage variation over time, the average irrecoverable and recoverable self-discharge currents of the battery after the first pulse charge and during the rest period are further determined to characterize the self-discharge characteristics of the battery. Accurate voltage sampling during the two pulse charging and resting processes enables the evaluation of the self-discharge current characteristics of the battery during self-discharge, resulting in accurate and reliable battery self-discharge characteristics.

[0107] In another embodiment of a method for testing battery self-discharge characteristics provided by the present invention, the step of determining the average self-discharge current of the battery under test when it is at rest after the first pulse charging based on the change in the voltage of the battery under test over time during the two pulse charging processes includes:

[0108] Determine the charging charge amount of pulse charging;

[0109] Reference Figure 5 Assuming the battery's initial stable open-circuit voltage is Voc_0 and the battery's charge is fixed (Q0), the battery's capacity returns to its initial charge, Q0, at any subsequent step, as long as the battery's stable open-circuit voltage reaches Voc_0. The same charge for the first and second pulse charging refers to a charge of ΔQ at time t1-t2 and a charge of ΔQ at time t3-t4.

[0110] Based on the change of the voltage of the battery under test over time during the two pulse charging processes, determining a curve function of the linear voltage decrease during the two rest times;

[0111] Among them, the curve function of the linear voltage drop during the two static times includes the curve function of the linear voltage drop during the t2'-t3 period during the first static time, and the curve function of the linear voltage drop during the t4'-t5 period during the second static time. According to the change of the voltage of the battery to be tested with time during the two pulse charging processes, the coordinate point positions of the voltage linear drop process during the two static times are determined to solve and determine the curve function of the voltage linear drop during the two static times.

[0112] Based on the charging charge, the initial open circuit voltage and the curve function, an average self-discharge current of the battery under test when it is at rest after the first pulse charging is determined.

[0113] Based on the curve function, a first theoretical open-circuit voltage at t2 when the first resting state begins, and a second theoretical open-circuit voltage at t4 when the second resting state begins can be determined. Then, based on the changing relationship between voltage and charge during the battery self-discharge process, the average self-discharge current of the battery under test during rest after the first pulse charging is determined.

[0114] Optionally, the step of determining the amount of charge for pulse charging includes:

[0115] The charge amount of the pulse charging is determined according to the average self-discharge current of the battery to be tested when it is at rest after the first pulse charging and the first resting time.

[0116] Take the average self-discharge current of the battery during the first static process as I_cha1, the charging charge as ΔQ, and the static time after the first pulse charging as Δt1 (Δt1=t3-t2). Since the charging charge of the first charging is all consumed when the voltage of the battery to be tested drops to the initial open circuit voltage during the first static process, I_cha1·Δt1=ΔQ. The charging charge of the pulse charging is determined according to the average self-discharge current of the battery to be tested during static state after the first pulse charging and the first static time.

[0117] In another embodiment of a method for testing battery self-discharge characteristics provided by the present invention, the step of determining a curve function of a linear voltage drop during two rest periods based on the change in voltage of the battery under test over time during two pulse charging processes includes:

[0118] According to the start time of the linear decrease in the open-circuit voltage of the battery to be tested when the battery to be tested is left at rest after the first pulse charging and the second pulse charging, the start voltage at the start time, the end time of the linear decrease in the open-circuit voltage of the battery to be tested, and the end voltage at the end time, a first curve function for the linear decrease in voltage during the first rest time and a second curve function for the linear decrease in voltage during the second rest time are determined.

[0119] Reference Figure 5 , when the battery to be tested is left at rest after the first pulse charge, the start time of the linear decrease of the open circuit voltage of the battery to be tested is t2', the end time of the linear decrease of the open circuit voltage of the battery to be tested is t3, and the end voltage of the end time is the open circuit voltage Voc_0 of the battery in the initial stable state. When the battery to be tested is left at rest after the second pulse charge, the start time of the linear decrease of the open circuit voltage of the battery to be tested is t4', the end time of the linear decrease of the open circuit voltage of the battery to be tested is t5, and the end voltage of the end time is also the open circuit voltage Voc_0 of the battery in the initial stable state. Thus, according to Figure 5The coordinates corresponding to t2' and t3 determine the first curve function of the linear voltage drop during the first static time. Figure 5 The coordinates corresponding to t4' and t5 determine the second curve function of the linear voltage drop during the second static time.

[0120] Optionally, the step of determining the average self-discharge current of the battery under test when it is at rest after the first pulse charging based on the charging charge, the initial open circuit voltage, and the curve function includes:

[0121] determining a first theoretical open-circuit voltage at the beginning of a first rest period based on the first curve function;

[0122] determining a second theoretical open-circuit voltage at the beginning of the second rest period based on the second curve function;

[0123] An average self-discharge current of the battery under test when it is at rest after the first pulse charging is determined based on the charging charge, the initial open circuit voltage, the first theoretical open circuit voltage, and the second theoretical open circuit voltage.

[0124] Reference Figure 5 A first theoretical open-circuit voltage Voc_1 at t2, when the first rest period begins, is determined based on the first curve function. A second theoretical open-circuit voltage Voc_2 at t4, when the second rest period begins, is determined based on the second curve function. The average self-discharge current of the battery under test during rest after the first pulse charging is then determined based on the changing relationship between voltage and charge during the battery self-discharge process.

[0125] Optionally, the step of determining an average self-discharge current of the battery under test when it is at rest after the first pulse charging based on the charging charge, the initial open-circuit voltage, the first theoretical open-circuit voltage, and the second theoretical open-circuit voltage includes:

[0126] Determining a self-discharge charge of the battery under test when it is at rest after the first pulse charging based on the charged charge, the initial open circuit voltage, the first theoretical open circuit voltage, and the second theoretical open circuit voltage;

[0127] Based on the self-discharge charge and the first rest time, an average self-discharge current of the battery to be tested is determined.

[0128] In this embodiment, according to the physical theorem of Q=ΔI×Δt, the self-discharge charge of the battery to be tested when it is at rest after the first pulse charging is determined based on the charging charge, the initial open-circuit voltage, the first theoretical open-circuit voltage, and the second theoretical open-circuit voltage; and the self-discharge average current of the battery to be tested is determined based on the self-discharge charge ΔQ and the first rest time Δt1.

[0129] In another embodiment of a method for testing battery self-discharge characteristics provided by the present invention, the self-discharge charge of the battery to be tested includes an irrecoverable self-discharge charge and a recoverable self-discharge charge. The step of determining the irrecoverable self-discharge charge of the battery to be tested when it is at rest after the first pulse charging based on the charged charge, the initial open-circuit voltage, the first theoretical open-circuit voltage, and the second theoretical open-circuit voltage includes:

[0130] determining a first voltage difference between the first theoretical open circuit voltage and the initial open circuit voltage;

[0131] determining a second voltage difference between the second theoretical open circuit voltage and the initial open circuit voltage;

[0132] An irrecoverable self-discharge charge amount is determined based on a difference between the first voltage difference and the second voltage difference, the second voltage difference, and the charged charge amount.

[0133] Reference Figure 5 At t1 and t3, the battery's charge is Q0 and its voltage is Voc_0. At t2, the charge is Q0+ΔQ, and its first theoretical open-circuit voltage is Voc_1 (Voc_1=Voc_0+Δu1). At t4, the charge is Q0+ΔQ, and its second theoretical open-circuit voltage is Voc_2 (Voc_2=Voc_0+Δu2). The excess charge during the second pulse charge is the charge caused by irrecoverable self-discharge during the rest period after the first pulse charge:

[0134]

[0135] Optionally, the step of determining the recoverable self-discharge charge of the battery under test when it is at rest after the first pulse charging based on the charged charge, the initial open circuit voltage, the first theoretical open circuit voltage, and the second theoretical open circuit voltage includes:

[0136] A recoverable self-discharge charge amount is determined based on the first voltage difference, the second voltage difference, and the charged charge amount.

[0137] The amount of charge caused by self-discharge that can be recovered during the rest time after the first pulse charge is

[0138]

[0139] Optionally, the average self-discharge current of the battery to be tested includes an irrecoverable self-discharge average current and a recoverable self-discharge average current, and the step of determining the average self-discharge current of the battery to be tested based on the self-discharge charge and the first rest time includes:

[0140] Determining an average irrecoverable self-discharge current of the battery to be tested based on the irrecoverable self-discharge charge and the first rest time;

[0141] Determining a recoverable self-discharge average current of the battery to be tested based on the recoverable self-discharge charge and the first rest time;

[0142] During the rest period after the first pulse charge, the average current of irrecoverable and recoverable self-discharge is:

[0143]

[0144] The average self-discharge current of the battery to be tested is determined based on the average irrecoverable self-discharge current and the average recoverable self-discharge current.

[0145] The average irrecoverable self-discharge current is I_cha1_che, and the average recoverable self-discharge current is I_cha1_ph. Take the average self-discharge current of the battery during the second static process as I_cha2, where the average irrecoverable self-discharge current is I_cha2_che and the average recoverable self-discharge current is I_cha2_ph, then:

[0146]

[0147] In one embodiment of the present invention, referring to Figure 5Assume that the open-circuit voltage of the battery is Voc_0 when it is initially stable, and that the battery's charge is fixed (Q0) in this state. In any subsequent process, as long as the battery's stable open-circuit voltage reaches Voc_0, the battery's capacity will be restored to the initial charge Q0. At time t1, the open-circuit voltage of the battery at the specified temperature is Voc_0, and its stable charge is Q0. The charge of the pulse charge at time t1-t2 is ΔQ. At time t2, the battery's charge is Qt2 = Q0 + ΔQ. After this, the battery is allowed to rest, and t2' is the time point when the nonlinear region transitions to the linear region during the voltage drop. At this point, the battery's open-circuit voltage is V_t2'. After a rest period of Δt1 (Δt1 = t3-t2), the battery's open-circuit voltage drops linearly to the initial open-circuit voltage Voc_0. Using t2, t2', t3, as well as V_t2' and Voc_0, the linear equation of the open-circuit voltage at rest after the first pulse charge is calculated and the theoretical voltage value Voc_1 of this curve at time t2 is inferred. This voltage represents the theoretical open-circuit voltage after the battery stabilizes and increases in charge after the first pulse charge. This solution eliminates the effects of the double layer and diffusion processes. At time t3, the battery's open-circuit voltage and capacity are both stable. The battery's capacity returns to its initial charge Q0. The rest time Δt1 can be considered the process of self-discharge, which consumes the battery's charge capacity. This process includes both irreversible and reversible self-discharge. Similarly, at time t3, the battery is subjected to the same pulse charge again, and the charge capacity remains ΔQ. t4 marks the end of the second pulse charge. Thereafter, the battery's open-circuit voltage changes similarly to the first time. Collect data at t4', V_t4', and t5, Voc_0. Using the same processing method, we obtain the theoretical stable open-circuit voltage Voc_2 of the battery at t4. Let the open-circuit voltage of the battery at t2' be Vt2', and the open-circuit voltage of the battery at t4' be Vt4'. Therefore, the average slopes of the open-circuit voltage after the first and second pulse discharges are:

[0148]

[0149] Then Voc_1 and Voc_2 are

[0150]

[0151] It is important to note that although the battery's charge at time t3 is equal to the initial capacity Q0, due to the irreversible self-discharge process during the static phase after the first pulse charge, the second charge of Q0 will make Voc_2 greater than Voc_1. In principle, the charge must be less than ΔQ to ensure that the theoretical stable voltage of the battery after the second pulse charge is equal to the theoretical stable voltage after the first pulse charge.

[0152] From the above analysis, we can know that the average self-discharge current of the battery during the first static process is I_cha1, of which the average irrecoverable self-discharge current is I_cha1_che, and the average recoverable self-discharge current is I_cha1_ph; the average self-discharge current of the battery during the second static process is I_cha2, of which the average irrecoverable self-discharge current is I_cha2_che, and the average recoverable self-discharge current is I_cha2_ph, then

[0153]

[0154] At the same time, because the amount of charge in the first pulse charging and the second pulse charging is the same, the amount of charge consumed in the first and second resting processes is the same, so

[0155] I_cha1·Δt1=ΔQ=I_cha2·Δt2

[0156] At t1 and t3, the battery's charge is Q0 and its voltage is Voc_0. At t2, the charge is Q0+ΔQ, and its theoretical stable open-circuit voltage is Voc_1 (Voc_1=Voc_0+Δu1). At t4, the charge is Q0+ΔQ, and its theoretical stable open-circuit voltage is Voc_2 (Voc_2=Voc_0+Δu2).

[0157] In the interval t4-t5, the battery self-discharge loss charge is ΔQ, that is, to make the theoretical stable open circuit voltage at t4 Voc_1, the corresponding charging charge is ΔQ'

[0158]

[0159] The extra charge from the second pulse charge changes Δu1 to Δu2, which is the charge caused by irrecoverable self-discharge during the rest period after the first pulse charge:

[0160]

[0161] The amount of charge caused by self-discharge that can be recovered during the rest time after the first pulse charge is the above ΔQ'

[0162]

[0163] During the rest period after the first pulse charge, the average current of irrecoverable and recoverable self-discharge is:

[0164]

[0165] In summary, the changes in the open-circuit voltage after pulse charging are distinguished. Based on the characteristics of irreversible and reversible self-discharge, the average current of irreversible and reversible self-discharge is distinguished by using two pulse charging and static processes, providing an effective detection method for battery performance degradation and internal performance evaluation. Based on the precise voltage sampling during the two pulse charging and static processes, the irreversible and reversible self-discharge currents during the battery self-discharge process are evaluated without introducing any interference, resulting in accurate testing, simple experimentation, high feasibility, and strong practicality.

[0166] In addition, refer to Figure 7 The embodiment of the present invention further provides a battery self-discharge characteristic testing device, the battery self-discharge characteristic testing device comprising:

[0167] A first charging and resting module M1 is used to obtain the initial open circuit voltage of the battery under test in a static and stable state, perform a first pulse charging on the battery under test, and then rest the battery;

[0168] a second charging and resting module M2, configured to perform a second pulse charging, which is the same as the first pulse charging, on the battery under test and rest the battery under test when the open circuit voltage of the battery under test drops to the initial open circuit voltage after the first pulse charging;

[0169] The calculation module M3 is used to determine the average self-discharge current of the battery under test when it is at rest after the first pulse charging based on the change in the voltage of the battery under test over time during the two pulse charging processes, when the open-circuit voltage of the battery under test drops to the initial open-circuit voltage after the second pulse charging. The average self-discharge current includes the average irrecoverable self-discharge current and the average recoverable self-discharge current.

[0170] Optionally, the calculation module is further used to determine the charging amount of the pulse charging;

[0171] Based on the change of the voltage of the battery under test over time during the two pulse charging processes, determining a curve function of the linear voltage decrease during the two rest times;

[0172] Based on the charging charge, the initial open circuit voltage and the curve function, an average self-discharge current of the battery to be tested when it is at rest after the first pulse charging is determined.

[0173] Optionally, the calculation module is further configured to determine the charge amount of the pulse charging according to the average self-discharge current of the battery to be tested when it is at rest after the first pulse charging and the first resting time.

[0174] Optionally, the calculation module is also used to determine a first curve function of the linear decrease in voltage during the first resting time and a second curve function of the linear decrease in voltage during the second resting time based on the start time of the linear decrease in the open circuit voltage of the battery to be tested when the battery to be tested is left at rest after the first pulse charging and the second pulse charging, the start voltage at the start time, the end time of the linear decrease in the open circuit voltage of the battery to be tested, and the end voltage at the end time.

[0175] Optionally, the calculation module is further configured to determine a first theoretical open circuit voltage at the beginning of the first rest period based on the first curve function;

[0176] determining a second theoretical open-circuit voltage at the beginning of the second rest period based on the second curve function;

[0177] An average self-discharge current of the battery under test when it is at rest after the first pulse charging is determined based on the charging charge, the initial open circuit voltage, the first theoretical open circuit voltage, and the second theoretical open circuit voltage.

[0178] Optionally, the calculation module is further configured to determine a self-discharge charge of the battery under test when it is at rest after the first pulse charging based on the charged charge, the initial open circuit voltage, the first theoretical open circuit voltage, and the second theoretical open circuit voltage;

[0179] Based on the self-discharge charge and the first rest time, an average self-discharge current of the battery to be tested is determined.

[0180] Optionally, the self-discharge charge of the battery to be tested includes an irrecoverable self-discharge charge and a recoverable self-discharge charge, and the calculation module is further used to determine a first voltage difference between the first theoretical open-circuit voltage and the initial open-circuit voltage;

[0181] determining a second voltage difference between the second theoretical open circuit voltage and the initial open circuit voltage;

[0182] An irrecoverable self-discharge charge amount is determined based on a difference between the first voltage difference and the second voltage difference, the second voltage difference, and the charged charge amount.

[0183] Optionally, the calculation module is further configured to determine a recoverable self-discharge charge amount based on the first voltage difference, the second voltage difference, and the charged charge amount.

[0184] Optionally, the average self-discharge current of the battery to be tested includes an irrecoverable self-discharge average current and a recoverable self-discharge average current, and the calculation module is further used to determine the irrecoverable self-discharge average current of the battery to be tested based on the irrecoverable self-discharge charge amount and the first rest time;

[0185] Determining a recoverable self-discharge average current of the battery to be tested based on the recoverable self-discharge charge and the first rest time;

[0186] The average self-discharge current of the battery to be tested is determined based on the average irrecoverable self-discharge current and the average recoverable self-discharge current.

[0187] The battery self-discharge characteristic testing device provided by the present invention utilizes the battery self-discharge characteristic testing method of the aforementioned embodiment to resolve the technical problem of the difficulty in accurately determining battery self-discharge characteristics in the prior art. Compared with the prior art, the battery self-discharge characteristic testing device provided by the embodiment of the present invention has the same beneficial effects as the battery self-discharge characteristic testing method provided by the aforementioned embodiment. Other technical features of the battery self-discharge characteristic testing device are the same as those disclosed in the aforementioned embodiment and are not further described here.

[0188] In addition, an embodiment of the present invention further provides a battery self-discharge characteristic testing device, which includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the computer program is configured to implement the steps of the battery self-discharge characteristic testing method described above.

[0189] In addition, an embodiment of the present invention further provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the steps of the battery self-discharge characteristic testing method described above are implemented.

[0190] It should be noted that, in this document, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or system comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or system. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or system comprising the element.

[0191] The serial numbers of the above embodiments of the present invention are for description only and do not represent the advantages or disadvantages of the embodiments.

[0192] Through the description of the above embodiments, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus the necessary general hardware platform, and of course can also be implemented by hardware, but in many cases the former is a better embodiment. Based on this understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes a number of instructions for enabling a terminal device (which can be a mobile phone, computer, server, or network device, etc.) to execute the methods described in each embodiment of the present invention.

[0193] The above are only preferred embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for testing battery self-discharge characteristics, characterized in that: The battery self-discharge characteristic testing method comprises the following steps: Obtaining an initial open circuit voltage of the battery under test in a static stable state, performing a first pulse charge on the battery under test and allowing it to stand; When the open circuit voltage of the battery under test drops to the initial open circuit voltage after the first pulse charging, performing a second pulse charging on the battery under test that is the same as the first pulse charging and allowing the battery to stand; When the open circuit voltage of the battery to be tested drops to the initial open circuit voltage after the second pulse charging, the average self-discharge current of the battery to be tested when it is at rest after the first pulse charging is determined based on the change in the voltage of the battery to be tested over time during the two pulse charging processes. The average self-discharge current includes the average irrecoverable self-discharge current and the average recoverable self-discharge current.

2. The battery self-discharge characteristic testing method according to claim 1, wherein: The step of determining the average self-discharge current of the battery under test when it is at rest after the first pulse charging based on the change of the voltage of the battery under test over time during the two pulse charging processes includes: Determine the charging charge amount of pulse charging; Based on the change of the voltage of the battery under test over time during the two pulse charging processes, determining a curve function of the linear voltage decrease during the two rest times; Based on the charging charge, the initial open circuit voltage and the curve function, an average self-discharge current of the battery under test when it is at rest after the first pulse charging is determined.

3. The battery self-discharge characteristic testing method according to claim 2, wherein: The step of determining the amount of charge for pulse charging comprises: The charge amount of the pulse charging is determined according to the average self-discharge current of the battery to be tested when it is at rest after the first pulse charging and the first resting time.

4. The battery self-discharge characteristic testing method according to claim 2, wherein: The step of determining a curve function of a linear voltage drop during two rest periods based on the change of the voltage of the battery under test over time during the two pulse charging processes includes: According to the start time of the linear decrease in the open-circuit voltage of the battery to be tested when the battery to be tested is left at rest after the first pulse charging and the second pulse charging, the start voltage at the start time, the end time of the linear decrease in the open-circuit voltage of the battery to be tested, and the end voltage at the end time, a first curve function for the linear decrease in voltage during the first rest time and a second curve function for the linear decrease in voltage during the second rest time are determined.

5. The battery self-discharge characteristic testing method according to claim 4, wherein: The step of determining the average self-discharge current of the battery under test when it is at rest after the first pulse charging based on the charging charge, the initial open circuit voltage and the curve function includes: determining a first theoretical open-circuit voltage at the beginning of a first rest period based on the first curve function; determining a second theoretical open-circuit voltage at the beginning of the second rest period based on the second curve function; An average self-discharge current of the battery under test when it is at rest after the first pulse charging is determined based on the charging charge, the initial open circuit voltage, the first theoretical open circuit voltage, and the second theoretical open circuit voltage.

6. The battery self-discharge characteristic testing method according to claim 5, wherein: The step of determining the self-discharge average current of the battery to be tested when it is at rest after the first pulse charging based on the charging charge, the initial open circuit voltage, the first theoretical open circuit voltage, and the second theoretical open circuit voltage includes: Determining a self-discharge charge of the battery under test when it is at rest after the first pulse charging based on the charged charge, the initial open circuit voltage, the first theoretical open circuit voltage, and the second theoretical open circuit voltage; Based on the self-discharge charge and the first rest time, an average self-discharge current of the battery to be tested is determined.

7. The battery self-discharge characteristic testing method according to claim 6, wherein: The self-discharge charge of the battery to be tested includes an irrecoverable self-discharge charge and a recoverable self-discharge charge. The step of determining the irrecoverable self-discharge charge of the battery to be tested when it is at rest after the first pulse charging based on the charged charge, the initial open circuit voltage, the first theoretical open circuit voltage, and the second theoretical open circuit voltage comprises: determining a first voltage difference between the first theoretical open circuit voltage and the initial open circuit voltage; determining a second voltage difference between the second theoretical open circuit voltage and the initial open circuit voltage; An irrecoverable self-discharge charge amount is determined based on a difference between the first voltage difference and the second voltage difference, the second voltage difference, and the charged charge amount.

8. The battery self-discharge characteristic testing method according to claim 7, wherein: The step of determining the recoverable self-discharge charge of the battery under test when it is at rest after the first pulse charging based on the charged charge, the initial open circuit voltage, the first theoretical open circuit voltage, and the second theoretical open circuit voltage comprises: A recoverable self-discharge charge amount is determined based on the first voltage difference, the second voltage difference, and the charged charge amount.

9. The battery self-discharge characteristic testing method according to claim 8, wherein: The average self-discharge current of the battery to be tested includes an irrecoverable self-discharge average current and a recoverable self-discharge average current. The step of determining the average self-discharge current of the battery to be tested based on the self-discharge charge and the first rest time comprises: Determining an average irrecoverable self-discharge current of the battery to be tested based on the irrecoverable self-discharge charge and the first rest time; Determining a recoverable self-discharge average current of the battery to be tested based on the recoverable self-discharge charge and the first rest time; The average self-discharge current of the battery to be tested is determined based on the average irrecoverable self-discharge current and the average recoverable self-discharge current.

10. A battery self-discharge characteristic testing device, characterized in that: The battery self-discharge characteristic testing device comprises: A first charging and resting module is used to obtain an initial open circuit voltage of the battery under test in a static and stable state, perform a first pulse charging on the battery under test, and rest the battery; a second charging and resting module, configured to perform a second pulse charging, which is the same as the first pulse charging, on the battery to be tested and rest the battery to be tested when the open circuit voltage of the battery to be tested drops to the initial open circuit voltage after the first pulse charging; a calculation module for determining, when the open-circuit voltage of the battery under test drops to the initial open-circuit voltage after the second pulse charging, an average self-discharge current of the battery under test when it is at rest after the first pulse charging based on the change in the voltage of the battery under test over time during the two pulse charging processes, wherein the average self-discharge current includes an average irrecoverable self-discharge current and an average recoverable self-discharge current.

11. A battery self-discharge characteristic testing device, characterized in that: The battery self-discharge characteristic testing device includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the computer program is configured to implement the steps of the battery self-discharge characteristic testing method according to any one of claims 1 to 9.

12. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of the battery self-discharge characteristic testing method according to any one of claims 1 to 9.

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