Accelerated test method for storage aging of lithium batteries, electronic equipment and storage medium

Abstract

The present application provides an accelerated test method, electronic device and storage medium for storage aging of lithium batteries. The test method includes: reverse charging a lithium battery to be tested that has been discharged to a preset cutoff voltage until the absolute value of the reverse charging energy reaches a preset energy value; wherein the preset energy value is calculated by the actual discharge energy obtained through each charge and discharge test; after the lithium battery to be tested in a negative energy state is left to stand, the lithium battery to be tested is subjected to a cyclic charge and discharge test, a reverse charge test and a storage test until the storage capacity of the lithium battery to be tested drops to the preset capacity. The present application can achieve the purpose of safely shortening the test cycle of lithium battery storage aging through negative energy storage, thereby meeting the needs of accelerated storage aging testing of lithium batteries.

Description

Technical Field

[0001] The present application relates to the field of lithium battery technology, and in particular to an accelerated testing method, electronic device, and storage medium for lithium battery storage aging. Background Art

[0002] Lithium-ion batteries have high power, energy density and reliability, and play a key role in the field of energy storage and power batteries.

[0003] During the storage process, lithium-ion batteries will inevitably age (calendar aging). During the development of lithium batteries, it usually takes a long time to test storage aging. In related technologies, high-temperature placement or floating charge are usually used to accelerate the storage aging of lithium-ion batteries.

[0004] However, high temperature has a low degree of acceleration on the storage aging of lithium batteries and cannot effectively improve the problem of long test cycles; while floating charge has a high probability of thermal runaway, which will affect the safety performance of lithium batteries. Therefore, the above method cannot meet the needs of accelerated storage aging testing of lithium batteries. Summary of the invention

[0005] In view of the above problems, the present application provides an accelerated testing method, electronic device and storage medium for lithium battery storage aging, which can solve the problem that related technologies cannot meet the needs of accelerated testing of lithium battery storage aging.

[0006] In a first aspect, the present application provides an accelerated testing method for storage aging of a lithium battery, comprising: reverse charging a lithium battery to be tested that has been discharged to a preset cutoff voltage until the absolute value of the reverse charging energy reaches a preset energy value; wherein the preset energy value is calculated from the actual discharge energy obtained through each charge and discharge test; after the lithium battery to be tested that is in a negative energy state is left to stand, a cyclic charge and discharge test, a reverse charge test, and a storage test are performed on the lithium battery to be tested until the storage capacity of the lithium battery to be tested drops to the preset capacity.

[0007] In the above scheme, by reverse charging the lithium battery to be tested that has been discharged to a preset cutoff voltage, and leaving the lithium battery to be tested in a negative energy state to stand, the decomposition reaction of the electrolyte at the positive and negative electrodes of the battery can be intensified by the negative energy state during the storage process, thereby accelerating the decomposition rate of the electrolyte, the solid dielectric interface and the electrochemical interface, and then accelerating the storage aging of the lithium-ion battery. Furthermore, by obtaining the actual discharge energy corresponding to the lithium battery to be tested in each charge and discharge test, and calculating the absolute value of the reverse charging energy corresponding to each reverse charge based on the actual discharge energy, the negative energy state during the storage process can be controlled to reduce the probability of triggering unexpected side reactions, thereby improving the safety performance of the lithium battery during the test process, achieving the purpose of safely shortening the test cycle of lithium battery storage aging, and then meeting the needs of lithium battery storage aging acceleration testing.

[0008] In some embodiments, the step of reverse charging the lithium battery to be tested that is discharged to a preset cut-off voltage until the absolute value of the reverse charging energy reaches a preset energy value includes: obtaining the first discharge energy of the lithium battery to be tested; determining the preset energy value corresponding to the first reverse charging based on the first discharge energy; reverse charging the lithium battery to be tested that is first discharged to the preset cut-off voltage until the absolute value of the reverse charging energy reaches the preset energy value corresponding to the first reverse charging; after the lithium battery to be tested in a negative energy state is left to stand, the lithium battery to be tested is subjected to a cyclic charge and discharge test, a reverse charging test, and a storage test until the storage capacity of the lithium battery to be tested is The step of reducing to a preset capacity comprises: after the lithium battery to be tested in a negative energy state is left to stand, performing a second charge and discharge test on the lithium battery to be tested to obtain a second discharge energy of the lithium battery to be tested; determining a preset energy value corresponding to a second reverse charge based on the second discharge energy; reverse charging the lithium battery to be tested that is discharged to a preset cut-off voltage for the second time until the absolute value of the reverse charge energy reaches the preset energy value corresponding to the second reverse charge; after the lithium battery to be tested in a negative energy state is left to stand, repeatedly performing the steps of charge and discharge test, reverse charge test and storage test until the storage capacity of the lithium battery to be tested is reduced to the preset capacity.

[0009] In the above scheme, the preset energy value corresponding to the first reverse charge is determined by the first discharge energy, and the lithium battery to be tested is reverse charged based on the preset energy value corresponding to the first reverse charge, and the second discharge energy of the lithium battery is obtained through the second charge and discharge test, so as to determine the preset energy value corresponding to the second reverse charge through the second discharge energy, and the lithium battery is reverse charged based on the preset energy value corresponding to the second reverse charge. The preset energy value required for each reverse charge can be accurately calculated based on the iterative discharge energy value obtained after each charge and discharge test, thereby further reducing the probability of triggering unexpected side reactions on the basis of accelerating the decomposition reaction, and then further improving the safety performance of the lithium battery during the storage process.

[0010] In some embodiments, the step of obtaining the first discharge energy of the lithium battery to be tested includes: discharging the lithium battery to be tested that is fully charged for the first time to a first voltage based on a first rate, and recording the discharge capacity obtained during the first discharge step as the first discharge capacity; wherein the first voltage is greater than a preset cut-off voltage; calculating according to the first discharge capacity to obtain a first energy curve corresponding to the first cycle; continuing to discharge the lithium battery to be tested that has been discharged to the first voltage to a preset cut-off voltage based on a second rate, and calculating based on the corresponding discharge capacity during the second discharge step to obtain a second energy curve corresponding to the first cycle; wherein the second rate is less than the first rate; and obtaining the first discharge energy based on the first energy curve and the second energy curve corresponding to the first cycle.

[0011] In the above scheme, by using a first rate to discharge the first fully charged lithium battery to be tested to a first voltage, and using a second rate to continue discharging the lithium battery to be tested that has been discharged to the first voltage to a preset cut-off voltage, and making the second rate smaller than the first rate, the influence of polarization at the end of discharge of the lithium battery to be tested on the discharge capacity can be reduced, so that the discharge capacity obtained in the second step of discharge is closer to the actual capacity at the end of discharge, and then the second energy curve is closer to the actual discharge energy at the end of discharge, so that the first discharge energy obtained by the test is more accurate, and then the effectiveness and safety of subsequent reverse charging and negative energy storage are improved. Furthermore, by using a larger first rate to discharge the first fully charged lithium battery to be tested to a first voltage, and recording the discharge capacity obtained in the first step of discharge as the first discharge capacity, the calculation efficiency of the iterative capacity value can be improved.

[0012] In some embodiments, the step of discharging the first fully charged lithium battery to be tested to a first voltage based on a first rate, and recording the discharge capacity obtained in the first discharge process as the first discharge capacity includes: charging the lithium battery to be tested for the first time at a first preset temperature until it is fully charged; after the first fully charged lithium battery to be tested is allowed to stand for a first preset time, a first discharge current corresponding to the first cycle is calculated according to the first rate and the rated capacity; the lithium battery to be tested is discharged to a first voltage based on the first discharge current corresponding to the first cycle, and the discharge capacity corresponding to the first discharge process is obtained to obtain the first discharge capacity; the step of continuing to discharge the lithium battery to be tested that is discharged to the first voltage to a preset cut-off voltage based on a second rate, and calculating based on the discharge capacity corresponding to the second discharge process to obtain a second energy curve corresponding to the first cycle includes: after the lithium battery to be tested that is discharged to the first voltage is allowed to stand for a first preset time, a second discharge current corresponding to the first cycle is calculated according to the second rate and the first discharge capacity; the lithium battery to be tested is discharged to a preset cut-off voltage based on the second discharge current corresponding to the first cycle, and the discharge capacity corresponding to the second discharge process is obtained to calculate the second energy curve corresponding to the first cycle.

[0013] In the above scheme, the first discharge current corresponding to the first cycle is calculated by the first rate and the rated capacity, and the lithium battery to be tested is discharged to the first voltage based on the first discharge current corresponding to the first cycle, so that the actual discharge capacity of the lithium battery to be tested before aging storage can be obtained. The second discharge current corresponding to the first cycle is calculated according to the second rate and the first discharge capacity, and the battery energy of the lithium battery to be tested can be adjusted to 0 (or close to 0) by a small rate current to effectively reduce the influence of polarization, thereby improving the test accuracy of the first discharge energy, and then accurately controlling the acceleration degree of negative energy storage.

[0014] In some embodiments, after the lithium battery to be tested in a negative energy state is allowed to stand, a second charge and discharge test is performed on the lithium battery to be tested to obtain the second discharge energy of the lithium battery to be tested, the step includes: allowing the lithium battery to be tested in a negative energy state to stand for a second preset time at a second preset temperature; charging the lithium battery to be tested for a second time until it is fully charged at a first preset temperature; after the fully charged lithium battery to be tested is allowed to stand for a first preset time, a first discharge current corresponding to the second cycle is calculated according to the first rate and the first discharge capacity; based on the first discharge current corresponding to the second cycle, the lithium battery to be tested is discharged to a first voltage to calculate the second discharge capacity and the first energy curve corresponding to the second cycle; after the lithium battery to be tested discharged to the first voltage is allowed to stand for a first preset time, a second discharge current corresponding to the second cycle is calculated according to the second rate and the second discharge capacity; based on the second discharge current corresponding to the second cycle, the lithium battery to be tested is discharged to a preset cut-off voltage to obtain the second energy curve corresponding to the second cycle; and the second discharge energy is obtained according to the first energy curve and the second energy curve corresponding to the second cycle.

[0015] In the above scheme, the first discharge current corresponding to the second cycle is calculated by the first rate and the first discharge capacity, and the current required for the first discharge process in the second cycle can be accurately calculated based on the actual discharge capacity of the lithium battery to be tested before aging storage, thereby improving the measurement accuracy of the second discharge capacity. The second discharge current corresponding to the second cycle is calculated according to the second rate and the second discharge capacity, and the current required for the second discharge process can be accurately calculated based on the iterative capacity value, so as to further reduce the polarization effect caused by discharge, thereby further improving the test accuracy of the second discharge energy, and then accurately controlling the acceleration degree of negative energy storage.

[0016] In some embodiments, the preset energy value is obtained by multiplying the actual discharge energy by a first preset ratio; wherein the first preset ratio is greater than or equal to 2% and less than or equal to 10%.

[0017] In the above scheme, by setting the first preset ratio, the preset energy value required for each reverse charging can be accurately controlled, thereby reducing the probability of safety problems occurring in the lithium battery to be tested during the negative energy storage process, thereby improving the safety of the test.

[0018] In some embodiments, the preset capacity is obtained by multiplying the initial discharge capacity by a second preset ratio; wherein the second preset ratio is greater than or equal to 60% and less than or equal to 70%.

[0019] In the above solution, by setting the second preset ratio, the actual battery capacity required when the test ends can be accurately known, so that the test can be ended in time, thereby further shortening the test cycle.

[0020] In some embodiments, the difference between the first voltage and the preset cut-off voltage is greater than or equal to 0.05V and less than or equal to 0.1V.

[0021] In the above solution, by making the difference between the first voltage and the preset cut-off voltage smaller, the first step of discharge can be cut off near the preset cut-off voltage, so that a smaller rate can be used for precise control during the second step of discharge.

[0022] In some embodiments, the first magnification is greater than or equal to 0.1C and less than 1C, and the second magnification is greater than or equal to 0.01C and less than or equal to 0.05C.

[0023] In the above scheme, by controlling the discharge rate in the first step of discharge to be greater than or equal to 0.1C and less than 1C, the discharge time of the lithium battery to be tested can be relatively short, which is beneficial to improving the test efficiency. By controlling the discharge rate in the second step of discharge to be greater than or equal to 0.01C and less than or equal to 0.05C, the influence of polarization can be effectively reduced, thereby improving the test accuracy of the first discharge energy, and then accurately controlling the acceleration degree of negative energy storage.

[0024] In some embodiments, the first preset temperature is 25°C, and the second preset temperature is greater than or equal to 45°C.

[0025] In the above scheme, by performing charge and discharge tests on the lithium battery to be tested at a temperature of 25°C, the capacity of the lithium battery to be tested can be accurately determined. By storing the lithium battery to be tested at a temperature greater than or equal to 45°C, the storage cycle of the lithium battery to be tested can be further accelerated by high temperature.

[0026] In some embodiments, the lithium battery to be tested includes a lithium iron phosphate system or a ternary lithium system.

[0027] In the above solution, by limiting the types of lithium batteries to be tested, the application scope of the testing method can be expanded.

[0028] In a second aspect, the present application provides an electronic device, comprising: a memory for storing program data, which, when executed, implements the steps in the accelerated testing method for storage aging of lithium batteries as described above; and a processor for executing program instructions stored in the memory to implement the steps in the accelerated testing method for storage aging of lithium batteries as described above.

[0029] In a third aspect, the present application provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the steps in the accelerated testing method for storage aging of lithium batteries as described above are implemented.

[0030] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The drawings herein are incorporated into the specification and constitute a part of the specification. These drawings illustrate embodiments consistent with the present application and are used together with the specification to illustrate the technical solution of the present application.

[0032] Figure 1 This is a flow chart of the first embodiment of the accelerated test method for storage aging of lithium batteries of the present application;

[0033] Figure 2 This is a flow chart of the second embodiment of the accelerated test method for storage aging of lithium batteries of the present application;

[0034] Figure 3 This is a flow chart of the third embodiment of the accelerated test method for storage aging of lithium batteries of the present application;

[0035] Figure 4 This is a flow chart of the fourth embodiment of the accelerated test method for storage aging of lithium batteries of the present application;

[0036] Figure 5 This is a flow chart of the fifth embodiment of the accelerated test method for storage aging of lithium batteries of the present application;

[0037] Figure 6 It is a line data graph corresponding to Examples 1, 2, 3 of the present application and the control group and the blank group;

[0038] Figure 7 It is a structural schematic diagram of an embodiment of the electronic device of the present application;

[0039] Figure 8 It is a structural schematic diagram of an implementation method of a computer-readable storage medium of the present application.

[0040] Reference numerals:

[0041] 70-electronic device, 71-memory, 72-processor;

[0042] 80-computer readable storage medium, 801-computer program. DETAILED DESCRIPTION

[0043] Below, the battery cells, batteries and electrical equipment of the present application are described in detail with appropriate reference to the accompanying drawings. However, there may be cases where unnecessary detailed descriptions are omitted. For example, there are cases where detailed descriptions of well-known matters and repeated descriptions of actually the same structures are omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate the understanding of those skilled in the art. In addition, the drawings and the following description are provided for those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0044] "Scope" disclosed in the present application is limited in the form of lower limit and upper limit, and a given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of a special range. The scope limited in this way can be including end values ​​or not including end values, and can be combined arbitrarily, that is, any lower limit can form a scope with any upper limit combination. For example, if the scope of 60-120 and 80-110 is listed for a specific parameter, it is understood that the scope of 60-110 and 80-120 is also expected. In addition, if the minimum range values ​​1 and 2 are listed, and if the maximum range values ​​3, 4 and 5 are listed, the following scope can be all expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In the present application, unless otherwise specified, the numerical range "ab" represents the abbreviation of any real number combination between a and b, wherein a and b are real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" are listed in this document, and "0-5" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0045] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0046] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0047] Unless otherwise specified, all steps of the present application may be performed sequentially or randomly, preferably sequentially. For example, a method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, a method may also include step (c), which means that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0048] If there is no special explanation, the "include" and "comprising" mentioned in this application represent open-ended or closed-ended expressions. For example, "include" and "comprising" may represent that other components not listed may also be included or only listed components may be included or only listed components may be included.

[0049] If not specifically stated, in this application, the term "or" is inclusive. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, any of the following conditions satisfies the condition "A or B": A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0050] During the storage process, lithium-ion batteries will inevitably age (calendar aging). During the development of lithium batteries, it usually takes a long time to test storage aging. In related technologies, high-temperature placement or floating charge are usually used to accelerate the storage aging of lithium-ion batteries.

[0051] However, high temperature has a low degree of acceleration on the storage aging of lithium batteries and cannot effectively improve the problem of long test cycles; while floating charge has a high probability of thermal runaway, which will affect the safety performance of lithium batteries. Therefore, the above method cannot meet the needs of accelerated storage aging testing of lithium batteries.

[0052] In order to solve the problem that the related technology cannot meet the needs of the accelerated storage aging test of lithium batteries, by reverse charging the lithium battery to be tested that is discharged to a preset cutoff voltage, and leaving the lithium battery to be tested in a negative energy state, the decomposition reaction of the electrolyte at the positive and negative electrodes of the battery can be aggravated by the negative energy state during the storage process, thereby accelerating the decomposition rate of the electrolyte, the solid dielectric interface and the electrochemical interface, and then realizing the acceleration of the storage aging of the lithium-ion battery. Furthermore, by obtaining the actual discharge energy corresponding to the lithium battery to be tested in each charge and discharge test, and calculating the absolute value of the reverse charging energy corresponding to each reverse charge based on the actual discharge energy, the negative energy state during the storage process can be controlled to reduce the probability of triggering unexpected side reactions, thereby improving the safety performance of the lithium battery during the test process, achieving the purpose of safely shortening the test cycle of the lithium battery storage aging, and then meeting the needs of the accelerated storage aging test of the lithium battery.

[0053] The test method disclosed in the embodiment of the present application can be used for the research and development test requirements of different types of lithium batteries in the new energy lithium battery industry. The different types of lithium batteries can be but are not limited to lithium iron phosphate systems or ternary lithium systems.

[0054] To this end, the first embodiment of the present application provides an accelerated test method for storage aging of a lithium battery, such as Figure 1 As shown, including:

[0055] S101: Reversely charge the lithium battery to be tested that has been discharged to a preset cut-off voltage until the absolute value of the reverse charging energy reaches a preset energy value; wherein the preset energy value is calculated from the actual discharge energy obtained through each charge and discharge test.

[0056] In this embodiment, the preset cut-off voltage is the rated lower limit voltage (V min ).

[0057] Specifically, reverse charging refers to forcing the battery cell of the lithium battery to be tested to be depleted to negative, that is, continuing to discharge after the battery capacity of the lithium battery to be tested drops to 0, which is equivalent to negative charging energy, so the absolute value of the reverse charging energy needs to be calculated.

[0058] Specifically, when a lithium battery is tested for storage aging, a cyclic charge and discharge test is performed on the lithium battery. The actual discharge energy obtained in each charge and discharge test is continuously decaying, that is, the actual discharge energy is an iterative value. The energy value required for reverse charging in each cycle is determined by the iterative value, so that the negative energy state during the storage process can be controlled.

[0059] S102: After the lithium battery to be tested in a negative energy state is left to stand, a cyclic charge and discharge test, a reverse charge test, and a storage test are performed on the lithium battery to be tested until the storage capacity of the lithium battery to be tested drops to a preset capacity.

[0060] During the first cycle of a lithium battery, the electrolyte and the negative electrode material will react at the solid-liquid phase level to form a layer of SEI (Solid Electrolyte Interface) film, and the electrolyte will form a layer of CEI (Chemical-Electrochemical Interface) film on the positive electrode material. The SEI film will protect the negative electrode material, and the CEI film will protect the positive electrode material, making the material structure less likely to collapse and increasing the cycle life of the electrode material. When the lithium battery is in a positive energy state, the electrolyte inside the lithium battery has an electrochemical stability window (that is, the normal working range). Within this stability window, the degree of side reactions between the electrolyte and the positive and negative electrodes of the lithium battery is very slight, so the corresponding storage test cycle is longer.

[0061] In the embodiment of the present application, by regulating the lithium battery to be tested to a negative energy state for storage, the positive electrode potential and the negative electrode potential inside the lithium battery to be tested can be made to exceed the stable window of the electrolyte, and the window matching degree between the electrolyte and the positive and negative electrodes can be reduced, thereby intensifying the side reactions of the electrolyte on the positive and negative electrode surfaces, that is, accelerating the decomposition process of the electrolyte on the positive and negative electrode surfaces, as well as the decomposition process of the SEI film and the CEI film, thereby accelerating the decomposition rate of the electrolyte, the solid dielectric interface and the electrochemical interface, and then achieving the acceleration of the storage aging of the lithium-ion battery.

[0062] In the technical solution of the embodiment of the present application, by reverse charging the lithium battery to be tested that has been discharged to a preset cut-off voltage, and leaving the lithium battery to be tested in a negative energy state, the decomposition reaction of the electrolyte at the positive and negative electrodes of the battery can be aggravated by the negative energy state during the storage process, thereby accelerating the decomposition rate of the electrolyte, the solid dielectric interface and the electrochemical interface, and then achieving the acceleration of the storage aging of the lithium-ion battery. Furthermore, by obtaining the actual discharge energy corresponding to the lithium battery to be tested in each charge and discharge test, and calculating the absolute value of the reverse charging energy corresponding to each reverse charge based on the actual discharge energy, the negative energy state during the storage process can be controlled to reduce the probability of triggering unexpected side reactions, thereby improving the safety performance of the lithium battery during the test process, achieving the purpose of safely shortening the test cycle of the lithium battery storage aging, and then meeting the needs of the lithium battery storage aging acceleration test.

[0063] In some embodiments, the preset energy value is obtained by multiplying the actual discharge energy by a first preset ratio, wherein the first preset ratio is greater than or equal to 2% and less than or equal to 10%.

[0064] In some specific embodiments, the first preset ratio may be 2%, 5% or 10%.

[0065] In the technical solution of the embodiment of the present application, by setting the first preset ratio, the preset energy value required for each reverse charging can be accurately controlled, thereby reducing the probability of safety problems occurring in the lithium battery to be tested during the negative energy storage process, thereby improving the safety of the test.

[0066] In some specific embodiments, the lithium battery to be tested includes a lithium iron phosphate system or a ternary lithium system.

[0067] In the technical solution of the embodiment of the present application, by limiting the type of lithium batteries to be tested, the application scope of the testing method can be expanded.

[0068] The second embodiment provides a method for accelerating the storage aging test of a lithium battery. Figure 2 As shown, including:

[0069] S201: Obtaining the first discharge energy of the lithium battery to be tested.

[0070] In the implementation manner of the present application, the first discharge energy refers to the battery energy that is completely released during the first discharge process.

[0071] S202: Determine a preset energy value corresponding to the first reverse charge based on the first discharge energy.

[0072] S203: Reversely charge the lithium battery to be tested that is discharged to a preset cut-off voltage for the first time, until the absolute value of the reverse charging energy reaches a preset energy value corresponding to the first reverse charging.

[0073] S204: After the lithium battery to be tested in the negative energy state is left to stand, a second charge and discharge test is performed on the lithium battery to be tested to obtain a second discharge energy of the lithium battery to be tested.

[0074] S205: Determine a preset energy value corresponding to the second reverse charge based on the second discharge energy.

[0075] S206: Reversely charge the lithium battery to be tested that is discharged to the preset cut-off voltage for the second time, until the absolute value of the reverse charging energy reaches a preset energy value corresponding to the second reverse charging.

[0076] S207: After the lithium battery to be tested in the negative energy state is left to stand, the steps of charge and discharge test, reverse charge test and storage test are repeatedly performed until the storage capacity of the lithium battery to be tested drops to a preset capacity.

[0077] In the technical solution of the embodiment of the present application, the preset energy value corresponding to the first reverse charge is determined by the first discharge energy, and the lithium battery to be tested is reversely charged based on the preset energy value corresponding to the first reverse charge, and the second discharge energy of the lithium battery is obtained through the second charge and discharge test, so as to determine the preset energy value corresponding to the second reverse charge through the second discharge energy, and the lithium battery is reversely charged based on the preset energy value corresponding to the second reverse charge. The preset energy value required for each reverse charge can be accurately calculated based on the iterative discharge energy value obtained after each charge and discharge test, thereby further reducing the probability of triggering unexpected side reactions on the basis of accelerating the decomposition reaction, and then further improving the safety performance of the lithium battery during the storage process.

[0078] The third embodiment provides a method for accelerating the storage aging test of a lithium battery. Figure 3 As shown, including:

[0079] S301: discharging the first fully charged lithium battery to be tested to a first voltage based on a first rate, and recording the discharge capacity obtained in the first step of the discharge process as the first discharge capacity; wherein the first voltage is greater than a preset cut-off voltage.

[0080] Specifically, the first discharge capacity is obtained by multiplying the constant current corresponding to the first discharge process by the time corresponding to the first discharge process.

[0081] S302: Calculate according to the first discharge capacity to obtain a first energy curve corresponding to the first cycle.

[0082] Specifically, the first energy curve is an integral curve, which is obtained by integrating the first discharge capacity and the corresponding voltage in the first step of discharge.

[0083] S303: continuing to discharge the lithium battery under test that has been discharged to the first voltage to a preset cut-off voltage based on a second rate, and calculating based on the corresponding discharge capacity during the second step of discharge to obtain a second energy curve corresponding to the first cycle; wherein the second rate is less than the first rate.

[0084] Specifically, the discharge capacity corresponding to the second-step discharge process is obtained by multiplying the constant current corresponding to the second-step discharge process by the time corresponding to the second-step discharge process.

[0085] Specifically, the second energy curve is an integral curve, which is obtained by integrating the discharge capacity and voltage corresponding to the second step of the discharge process.

[0086] S304: Obtaining the first discharge energy according to the first energy curve and the second energy curve corresponding to the first cycle.

[0087] S305: Determine a preset energy value corresponding to the first reverse charge based on the first discharge energy.

[0088] S306: Reversely charge the lithium battery to be tested that is discharged to the preset cut-off voltage for the first time, until the absolute value of the reverse charging energy reaches a preset energy value corresponding to the first reverse charging.

[0089] S307: After the lithium battery to be tested in the negative energy state is left to stand, a second charge and discharge test is performed on the lithium battery to be tested to obtain a second discharge energy of the lithium battery to be tested.

[0090] S308: Determine a preset energy value corresponding to the second reverse charge based on the second discharge energy.

[0091] S309: Reversely charge the lithium battery to be tested that is discharged to the preset cut-off voltage for the second time, until the absolute value of the reverse charging energy reaches a preset energy value corresponding to the second reverse charging.

[0092] S310: After the lithium battery to be tested in a negative energy state is left to stand, the steps of charge and discharge test, reverse charge test and storage test are repeatedly performed until the storage capacity of the lithium battery to be tested drops to a preset capacity.

[0093] In the technical solution of the embodiment of the present application, the first discharge current corresponding to the first cycle is calculated by the first rate and the rated capacity, and the lithium battery to be tested is discharged to the first voltage based on the first discharge current corresponding to the first cycle, so that the actual discharge capacity of the lithium battery to be tested before aging storage can be obtained. The second discharge current corresponding to the first cycle is calculated according to the second rate and the first discharge capacity, and the battery energy of the lithium battery to be tested can be adjusted to 0 (or close to 0) by a small rate current to effectively reduce the influence of polarization, thereby improving the test accuracy of the first discharge energy, and then accurately controlling the acceleration degree of negative energy storage.

[0094] In some embodiments, the difference between the first voltage and the preset cut-off voltage is greater than or equal to 0.05V and less than or equal to 0.1V.

[0095] In a specific embodiment, the lithium battery to be tested is a lithium iron phosphate system, and its preset cut-off voltage is 2.5V, and the corresponding first voltage may be 2.55V or 2.6V.

[0096] In another specific embodiment, the lithium battery to be tested is a ternary lithium system, and its preset cut-off voltage is 2.7V, then the corresponding first voltage may be 2.78V or 2.8V.

[0097] In the technical solution of the embodiment of the present application, by making the difference between the first voltage and the preset cut-off voltage smaller, the first step of discharge can be cut off near the preset cut-off voltage, so that a smaller rate can be used for precise control during the second step of discharge.

[0098] In some embodiments, the first magnification is greater than or equal to 0.1C and less than 1C, and the second magnification is greater than or equal to 0.01C and less than or equal to 0.05C.

[0099] In a specific embodiment, the first magnification is 0.33C, and the second magnification is 0.02C.

[0100] In the technical solution of the embodiment of the present application, by controlling the discharge rate in the first step of the discharge process to be greater than or equal to 0.1C and less than 1C, the discharge time of the lithium battery to be tested can be relatively short, which is conducive to improving the test efficiency. By controlling the discharge rate in the second step of the discharge process to be greater than or equal to 0.01C and less than or equal to 0.05C, the influence of polarization can be effectively reduced, thereby improving the test accuracy of the first discharge energy, and then accurately controlling the acceleration degree of negative energy storage.

[0101] In some embodiments, the preset capacity is obtained by multiplying the first discharge capacity by a second preset ratio, wherein the second preset ratio is greater than or equal to 60% and less than or equal to 70%.

[0102] In a specific embodiment, the second preset ratio is 60%, 65% or 70%.

[0103] In the technical solution of the embodiment of the present application, by setting the second preset ratio, the actual battery capacity required when the test ends can be accurately known, and the test can be ended in time, thereby further shortening the test cycle.

[0104] The fourth embodiment provides a method for accelerating the storage aging test of a lithium battery. Figure 4 As shown, including:

[0105] S401: At a first preset temperature, the lithium battery to be tested is charged for the first time until it is fully charged.

[0106] S402: After the lithium battery to be tested is fully charged for the first time, it is left to stand for a first preset time, and a first discharge current corresponding to the first cycle is calculated according to a first rate and a rated capacity.

[0107] In a specific embodiment, the rated capacity of the ternary lithium system lithium battery to be tested is 100 Ah (ampere-hour), the first rate is 0.33C, and the first discharge current is 0.33×100=33A.

[0108] In another specific embodiment, the rated capacity of the lithium iron phosphate system lithium battery to be tested is 200 Ah (ampere-hour), the first rate is 0.33C, and the first discharge current is 0.33×200=66A.

[0109] S403: discharging the lithium battery to be tested to a first voltage based on a first discharge current corresponding to a first cycle, and obtaining a discharge capacity corresponding to the first discharge process to obtain a first discharge capacity.

[0110] S404: Calculate according to the first discharge capacity to obtain a first energy curve corresponding to the first cycle.

[0111] S405: After the lithium battery to be tested is discharged to the first voltage and is left to stand for a first preset time, a second discharge current corresponding to the first cycle is calculated according to the second rate and the first discharge capacity.

[0112] In a specific embodiment, the first discharge capacity of the ternary lithium system lithium battery to be tested is 90Ah, the second rate is 0.02C, and the second discharge current is 0.02×90=1.8A.

[0113] In another specific embodiment, the first discharge capacity of the lithium iron phosphate system lithium battery to be tested is 180Ah, the second rate is 0.02C, and the second discharge current is 0.02×180=3.6A.

[0114] S406: Discharging the lithium battery to be tested to a preset cut-off voltage based on a second discharge current corresponding to the first cycle, obtaining a discharge capacity corresponding to the second step of discharge, and calculating a second energy curve corresponding to the first cycle.

[0115] S407: Obtaining the first discharge energy according to the first energy curve and the second energy curve corresponding to the first cycle.

[0116] S408: Determine a preset energy value corresponding to the first reverse charge based on the first discharge energy.

[0117] S409: Reversely charge the lithium battery to be tested that is discharged to the preset cut-off voltage for the first time, until the absolute value of the reverse charging energy reaches the preset energy value corresponding to the first reverse charging.

[0118] S410: After the lithium battery to be tested in a negative energy state is left to stand, a second charge and discharge test is performed on the lithium battery to be tested to obtain a second discharge energy of the lithium battery to be tested.

[0119] S411: Determine a preset energy value corresponding to the second reverse charge based on the second discharge energy.

[0120] S412: Reversely charge the lithium battery to be tested that is discharged to the preset cut-off voltage for the second time, until the absolute value of the reverse charging energy reaches a preset energy value corresponding to the second reverse charging.

[0121] S413: After the lithium battery to be tested in the negative energy state is left to stand, the steps of charge and discharge test, reverse charge test and storage test are repeatedly performed until the storage capacity of the lithium battery to be tested drops to a preset capacity.

[0122] In the technical solution of the embodiment of the present application, the first discharge current corresponding to the first cycle is calculated by the first rate and the rated capacity, and the lithium battery to be tested is discharged to the first voltage based on the first discharge current corresponding to the first cycle, so that the actual discharge capacity of the lithium battery to be tested before aging storage can be obtained. The second discharge current corresponding to the first cycle is calculated according to the second rate and the first discharge capacity, and the battery energy of the lithium battery to be tested can be adjusted to 0 (or close to 0) by a small rate current to effectively reduce the influence of polarization, thereby improving the test accuracy of the first discharge energy, and then accurately controlling the acceleration degree of negative energy storage.

[0123] In some embodiments, the first preset temperature is 25°C.

[0124] In the technical solution of the embodiment of the present application, by performing a charge and discharge test on the lithium battery to be tested at a temperature of 25° C., the capacity of the lithium battery to be tested can be accurately determined.

[0125] In some embodiments, the first preset time is 10 minutes.

[0126] Specifically, the discharge capacity test includes the following process: (1) at 25°C, the lithium battery to be tested is discharged at a constant current of 0.33C to 0; (2) after standing at 25°C for 10 min, it is charged at a constant current of 0.33C to the rated upper limit voltage; (3) under the condition of the rated upper limit voltage, it is charged to 0.05C at a constant voltage; (4) after standing at 25°C for 10 min, it is discharged at a constant current of 0.33C to the first voltage.

[0127] The discharge energy test includes the following process: (1) at 25°C, the lithium battery to be tested is discharged at a constant current of 0.33C to 0; (2) after standing at 25°C for 10 min, it is charged at a constant current of 0.33C to the rated upper limit voltage; (3) it is charged at a constant voltage to 0.05C under the rated upper limit voltage condition; (4) after standing at 25°C for 10 min, it is discharged at a constant current of 0.33C to the first voltage; (5) after standing at 25°C for 10 min, it is discharged at a constant current of 0.02C to the preset cut-off voltage.

[0128] In other embodiments, the first magnification may also be 0.1C, 0.2C, 0.5C, 0.8C or 1C, etc. In other embodiments, the second magnification may also be 0.01C, 0.03C, 0.04C or 0.05C, etc.

[0129] The fifth embodiment provides a method for accelerating the storage aging test of a lithium battery. Figure 5 As shown, including:

[0130] S501: Obtaining the first discharge energy of the lithium battery to be tested.

[0131] S502: Determine a preset energy value corresponding to the first reverse charge based on the first discharge energy.

[0132] S503: Reversely charge the lithium battery to be tested that is discharged to a preset cut-off voltage for the first time, until the absolute value of the reverse charging energy reaches a preset energy value corresponding to the first reverse charging.

[0133] S504: At a second preset temperature, the lithium battery to be tested in a negative energy state is allowed to stand for a second preset time.

[0134] S505: At the first preset temperature, the lithium battery to be tested is charged for the second time after being left to stand until it is fully charged.

[0135] S506: After the second fully charged lithium battery to be tested is left to stand for a first preset time, a first discharge current corresponding to a second cycle is calculated according to the first rate and the first discharge capacity.

[0136] In a specific embodiment, the first discharge capacity of the ternary lithium system lithium battery to be tested is 90Ah, the first rate is 0.33C, and the first discharge current corresponding to the second cycle is 0.33×90=29.7A.

[0137] In another specific embodiment, the first discharge capacity of the lithium iron phosphate system lithium battery to be tested is 180Ah, the first rate is 0.33C, and the first discharge current corresponding to the second cycle is 0.33×180=59.4A.

[0138] S507: discharging the lithium battery to be tested to a first voltage based on the first discharge current corresponding to the second cycle, so as to calculate a second discharge capacity and a first energy curve corresponding to the second cycle.

[0139] S508: After the lithium battery to be tested is discharged to the first voltage and is left to stand for a first preset time, a second discharge current corresponding to a second cycle is calculated according to a second rate and a second discharge capacity.

[0140] In a specific embodiment, the second discharge capacity of the ternary lithium system lithium battery to be tested is 80Ah, and the second rate is 0.02C, then the second discharge current corresponding to the second cycle is 0.02×80=1.6A.

[0141] In another specific embodiment, the second discharge capacity of the lithium iron phosphate system lithium battery to be tested is 160Ah, and the second rate is 0.02C, then the second discharge current corresponding to the second cycle is 0.02×160=3.2A.

[0142] S509: Discharging the lithium battery to be tested to a preset cut-off voltage based on a second discharge current corresponding to the second cycle, and obtaining a second energy curve corresponding to the second cycle.

[0143] S510: Obtaining a second discharge energy according to the first energy curve and the second energy curve corresponding to the second cycle.

[0144] S511: Determine a preset energy value corresponding to the second reverse charge based on the second discharge energy.

[0145] S512: Reversely charge the lithium battery to be tested that is discharged to the preset cut-off voltage for the second time, until the absolute value of the reverse charging energy reaches a preset energy value corresponding to the second reverse charging.

[0146] S513: After the lithium battery to be tested in the negative energy state is left to stand, the steps of charge and discharge test, reverse charge test and storage test are repeatedly performed until the storage capacity of the lithium battery to be tested drops to a preset capacity.

[0147] In the technical solution of the embodiment of the present application, the first discharge current corresponding to the second cycle is calculated by the first rate and the first discharge capacity, and the current required for the first discharge process in the second cycle can be accurately calculated based on the actual discharge capacity of the lithium battery to be tested before aging storage, thereby improving the measurement accuracy of the second discharge capacity. The second discharge current corresponding to the second cycle is calculated according to the second rate and the second discharge capacity, and the current required for the second discharge process can be accurately calculated based on the iterative capacity value, so as to further reduce the polarization effect caused by the discharge, thereby further improving the test accuracy of the second discharge energy, and then accurately controlling the acceleration degree of negative energy storage.

[0148] In some embodiments, the second preset temperature is greater than or equal to 45°C.

[0149] In a specific embodiment, the second preset temperature may be 45°C, 50°C or 60°C.

[0150] In the technical solution of the embodiment of the present application, by storing the lithium battery to be tested at a temperature greater than or equal to 45° C., the storage cycle of the lithium battery to be tested can be further accelerated by the high temperature.

[0151] In some embodiments, the second preset time is 15 days.

[0152] Specifically, the storage aging test includes the following process: (1) at 25°C, the lithium battery to be tested is discharged at a constant current of 0.33C to 0; (2) after standing at 25°C for 10 min, the constant current is charged at 0.33C to the rated upper limit voltage; (3) constant voltage is charged to 0.05C under the rated upper limit voltage condition; (4) after standing at 25°C for 10 min, the constant current is discharged at 0.33C to the first voltage; (5) after standing at 25°C for 10 min, the constant current is discharged at 0.02C to the preset cut-off voltage; (6) after standing at 25°C for 5 to 10 min, the constant current is discharged at 0.02C to 5% of the initial discharge energy; (7) standing at 45°C for 15 days; (8) steps (2) to (7) are cycled until the storage capacity of the lithium battery to be tested drops to 70% of the initial discharge capacity.

[0153] In other embodiments, the first preset ratio may also be 2% or 10%. In other embodiments, the second preset ratio may also be 60% or 65%.

[0154] To facilitate understanding of the embodiments of the present application, the present application provides the following non-limiting embodiments to further explain the present application in detail.

[0155] Example 1

[0156] (1) At 25°C, discharge at a constant current of 0.33C to 0; (2) After standing at 25°C for 10 min, charge at a constant current of 0.33C to the rated upper limit voltage; (3) Charge at a constant voltage to 0.05C under the rated upper limit voltage condition; (4) After standing at 25°C for 10 min, discharge at a constant current of 0.33C to a first voltage; (5) After standing at 25°C for 10 min, discharge at a constant current of 0.02C to a preset cut-off voltage; (6) After standing at 25°C for 5 to 10 min, discharge at a constant current of 0.02C to 2% of the first discharge energy; (7) Stand at 45°C for 15 days; (8) Repeat steps (2) to (7) 11 times.

[0157] Example 2

[0158] (1) At 25°C, discharge at a constant current of 0.33C to 0; (2) After standing at 25°C for 10 min, charge at a constant current of 0.33C to the rated upper limit voltage; (3) Charge at a constant voltage to 0.05C under the rated upper limit voltage condition; (4) After standing at 25°C for 10 min, discharge at a constant current of 0.33C to a first voltage; (5) After standing at 25°C for 10 min, discharge at a constant current of 0.02C to a preset cut-off voltage; (6) After standing at 25°C for 5 to 10 min, discharge at a constant current of 0.02C to 5% of the first discharge energy; (7) Stand at 45°C for 15 days; (8) Repeat steps (2) to (7) 11 times.

[0159] Example 3

[0160] (1) At 25°C, discharge at a constant current of 0.33C to 0; (2) After standing at 25°C for 10 min, charge at a constant current of 0.33C to the rated upper limit voltage; (3) Charge at a constant voltage to 0.05C under the rated upper limit voltage condition; (4) After standing at 25°C for 10 min, discharge at a constant current of 0.33C to a first voltage; (5) After standing at 25°C for 10 min, discharge at a constant current of 0.02C to a preset cut-off voltage; (6) After standing at 25°C for 5 to 10 min, discharge at a constant current of 0.02C to 10% of the first discharge energy; (7) Stand at 45°C for 15 days; (8) Repeat steps (2) to (7) 11 times.

[0161] Control group

[0162] (1) At 25°C, discharge at a constant current of 0.33C to 0; (2) After standing at 25°C for 10 min, charge at a constant current of 0.33C to the rated upper limit voltage; (3) Charge at a constant voltage of 0.05C under the rated upper limit voltage condition; (4) After standing at 25°C for 10 min, discharge at a constant current of 0.33C to a preset cut-off voltage; (5) After standing at 25°C for 10 min, charge at a constant current of 0.33C to the rated upper limit voltage; (6) Charge at a constant voltage of 0.05C under the rated upper limit voltage condition; (7) After standing at 25°C for 10 min, stand at 45°C for 15 days; (8) Repeat steps (2) to (7) 11 times.

[0163] For the lithium batteries to be tested obtained in Examples 1, 2, 3 and Control Groups 1 and 2, the actual discharge capacity of the lithium batteries to be tested after each cycle was tested, and the discharge capacity retention rate was calculated based on the actual test results and the rated capacity. The test results are shown in Table 1 and Figure 6 As shown:

[0164] Table 1 Discharge capacity retention after multiple cycles

[0165]

[0166] As can be seen from the above table, after multiple cycles, compared with the control group using full charge aging storage (positive energy storage), Examples 1, 2, and 3 using negative energy storage have better acceleration effects, indicating that the test method used in the embodiments of the present application can better achieve the acceleration of lithium-ion battery storage aging. Furthermore, the discharge capacity retention rate corresponding to Examples 1, 2, and 3 gradually decreases, indicating that the acceleration effect increases with the increase in the degree of negative energy storage, that is, the storage life of the lithium battery to be tested decreases with the increase in the degree of negative energy storage. Therefore, the embodiments of the present application can meet the needs of lithium battery storage aging acceleration testing.

[0167] The present application provides an electronic device.

[0168] See also Figure 7 , Figure 7 Schematic diagram of the structure of an electronic device of the present application. Figure 7 As shown, in this embodiment, the electronic device 70 includes a memory 71 and a processor 72 .

[0169] In this embodiment, the memory 71 is used to store program data, and when the program data is executed, the steps in the accelerated test method for storage aging of lithium batteries as described above are implemented; the processor 72 is used to execute the program instructions stored in the memory 71 to implement the steps in the accelerated test method for storage aging of lithium batteries as described above.

[0170] Specifically, the processor 72 is used to control itself and the memory 71 to implement the steps in the test method as described above. The processor 72 can also be called a CPU (Central Processing Unit). The processor 72 may be an integrated circuit chip with signal processing capabilities. The processor 72 can also be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor, etc. In addition, the processor 72 can be implemented by multiple integrated circuit chips.

[0171] In the technical solution of the embodiment of the present application, the processor 72 is used to reversely charge the lithium battery to be tested that is discharged to a preset cut-off voltage, and the lithium battery to be tested in a negative energy state is left to stand, so that the decomposition reaction of the electrolyte at the positive and negative electrodes of the battery can be aggravated by the negative energy state during the storage process, thereby accelerating the decomposition rate of the electrolyte, the solid dielectric interface and the electrochemical interface, and then realizing the acceleration of the storage aging of the lithium-ion battery. Furthermore, by obtaining the actual discharge energy corresponding to the lithium battery to be tested in each charge and discharge test, and calculating the absolute value of the reverse charging energy corresponding to each reverse charge based on the actual discharge energy, the negative energy state during the storage process can be controlled to reduce the probability of triggering unexpected side reactions, thereby improving the safety performance of the lithium battery during the test process, achieving the purpose of safely shortening the test cycle of the lithium battery storage aging, and then meeting the needs of the lithium battery storage aging acceleration test.

[0172] The present application provides a computer-readable storage medium.

[0173] See also Figure 8 , Figure 8 It is a structural schematic diagram of an implementation method of a computer-readable storage medium of the present application.

[0174] The computer-readable storage medium 80 includes a computer program 801 stored on the computer-readable storage medium 80 . When the computer program 801 is executed by the processor, the steps in the above-mentioned test method are implemented.

[0175] The above description is only an implementation method of the present application, and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. An accelerated test method for storage aging of lithium batteries, characterized in that: include: Reverse charging the lithium battery to be tested that has been discharged to a preset cut-off voltage until the absolute value of the reverse charging energy reaches a preset energy value; wherein the preset energy value is calculated from the actual discharge energy obtained through each charge and discharge test; The step of reversely charging the lithium battery to be tested that has been discharged to a preset cut-off voltage until the absolute value of the reverse charging energy reaches a preset energy value comprises: Obtaining the first discharge energy of the lithium battery to be tested; Determining a preset energy value corresponding to the first reverse charge based on the first discharge energy; Reverse charging the lithium battery to be tested that is discharged to the preset cut-off voltage for the first time, until the absolute value of the reverse charging energy reaches the preset energy value corresponding to the first reverse charging; After the lithium battery to be tested in a negative energy state is left at rest, a cyclic charge and discharge test, a reverse charge test, and a storage test are performed on the lithium battery to be tested until the storage capacity of the lithium battery to be tested drops to a preset capacity, including: after the lithium battery to be tested in a negative energy state is left at rest, a second charge and discharge test is performed on the lithium battery to be tested to obtain a second discharge energy of the lithium battery to be tested; Determining a preset energy value corresponding to a second reverse charge based on the second discharge energy; Reverse charging the lithium battery to be tested that is discharged to the preset cut-off voltage for the second time, until the absolute value of the reverse charging energy reaches the preset energy value corresponding to the second reverse charging; After the lithium battery to be tested in a negative energy state is left to stand, the steps of the charge and discharge test, the reverse charge test and the storage test are repeatedly performed until the post-storage capacity of the lithium battery to be tested drops to the preset capacity.

2. The testing method according to claim 1, characterized in that: The step of obtaining the first discharge energy of the lithium battery to be tested includes: Discharging the first fully charged lithium battery to be tested to a first voltage based on a first rate, and recording the discharge capacity obtained in the first step of the discharge process as the first discharge capacity; wherein the first voltage is greater than the preset cut-off voltage; Calculating according to the first discharge capacity to obtain a first energy curve corresponding to the first cycle; The lithium battery to be tested, which has been discharged to the first voltage, is further discharged to the preset cut-off voltage based on a second rate, and a calculation is performed based on the corresponding discharge capacity during the second step of discharge to obtain a second energy curve corresponding to the first cycle; wherein the second rate is less than the first rate; The first discharge energy is obtained according to the first energy curve and the second energy curve corresponding to the first cycle.

3. The testing method according to claim 2, characterized in that: The step of discharging the first fully charged lithium battery to be tested to a first voltage based on a first rate, and recording the discharge capacity obtained in the first discharge process as the first discharge capacity, comprises: At a first preset temperature, charging the lithium battery to be tested for the first time until it is fully charged; After the first fully charged lithium battery to be tested is left to stand for a first preset time, a first discharge current corresponding to the first cycle is calculated according to the first rate and the rated capacity; Discharging the lithium battery to be tested to the first voltage based on the first discharge current corresponding to the first cycle, and acquiring the discharge capacity corresponding to the first discharge process to obtain the first discharge capacity; The step of continuing to discharge the lithium battery under test that has been discharged to the first voltage to the preset cut-off voltage based on the second rate, and calculating based on the corresponding discharge capacity during the second step of discharge to obtain the second energy curve corresponding to the first cycle includes: After the lithium battery to be tested is discharged to the first voltage and is left to stand for the first preset time, a second discharge current corresponding to the first cycle is calculated according to the second rate and the first discharge capacity; The lithium battery to be tested is discharged to the preset cut-off voltage based on the second discharge current corresponding to the first cycle, and the discharge capacity corresponding to the second step of discharge is obtained to calculate the second energy curve corresponding to the first cycle.

4. The testing method according to claim 3, characterized in that: The step of performing a second charge and discharge test on the lithium battery to be tested after the lithium battery to be tested in the negative energy state is left to stand to obtain the second discharge energy of the lithium battery to be tested comprises: At a second preset temperature, allowing the lithium battery to stand in a negative energy state for a second preset time; At the first preset temperature, charging the lithium battery to be tested for the second time after being left to stand until it is fully charged; After the second fully charged lithium battery to be tested is left to stand for the first preset time, a first discharge current corresponding to the second cycle is calculated according to the first rate and the first discharge capacity; Discharging the lithium battery to be tested to the first voltage based on the first discharge current corresponding to the second cycle, so as to calculate a second discharge capacity and a first energy curve corresponding to the second cycle; After the lithium battery to be tested is discharged to the first voltage and is left to stand for the first preset time, a second discharge current corresponding to the second cycle is calculated according to the second rate and the second discharge capacity; Discharging the lithium battery to be tested to the preset cut-off voltage based on the second discharge current corresponding to the second cycle, and acquiring a second energy curve corresponding to the second cycle; The second discharge energy is obtained according to the first energy curve and the second energy curve corresponding to the second cycle.

5. The testing method according to any one of claims 1 to 4, characterized in that: The preset energy value is obtained by multiplying the actual discharge energy by a first preset ratio; Among them, the first preset ratio is greater than or equal to 2% and less than or equal to 10%.

6. The testing method according to claim 2, characterized in that: The preset capacity is obtained by multiplying the first discharge capacity by a second preset ratio; Wherein, the second preset ratio is greater than or equal to 60% and less than or equal to 70%.

7. The testing method according to any one of claims 2 to 4, characterized in that: A difference between the first voltage and the preset cut-off voltage is greater than or equal to 0.05V and less than or equal to 0.1V.

8. The testing method according to any one of claims 2 to 4, characterized in that: The first magnification is greater than or equal to 0.1C and less than 1C, and the second magnification is greater than or equal to 0.01C and less than or equal to 0.05C.

9. The testing method according to claim 4, characterized in that: The first preset temperature is 25° C., and the second preset temperature is greater than or equal to 45° C.

10. The testing method according to claim 1, characterized in that: The lithium battery to be tested includes a lithium iron phosphate system or a ternary lithium system.

11. An electronic device, characterized in that: include: A memory for storing program data, wherein the stored program data, when executed, implements the steps in the accelerated test method for storage aging of a lithium battery according to any one of claims 1 to 10; A processor, configured to execute program instructions stored in the memory to implement the steps in the accelerated testing method for storage aging of a lithium battery as described in any one of claims 1 to 10.

12. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by the processor, the steps in the accelerated testing method for storage aging of a lithium battery as claimed in any one of claims 1 to 10 are implemented.

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