Battery self-discharge test method, battery self-discharge test system, computer equipment and storage medium

Abstract

The invention relates to the technical field of batteries, and discloses a battery self-discharge test method, a battery self-discharge test system, a computer device and a storage medium, and the method comprises the steps: carrying out the charge adjustment to a first target SOC, and then carrying out the discharge adjustment to the first target SOC. According to the characteristic that the voltage rebound directions of the two load adjusting modes are opposite, the negative effects of the two load adjusting modes are subtracted and counteracted, and then the self-discharge voltage drop rate of the battery is calculated and determined according to the voltage monitored in the standing period under the two load adjusting modes so as to judge whether the self-discharge rate of the battery meets the standard or not, so that higher test accuracy can be ensured, and the test efficiency is improved. And moreover, the test efficiency can be greatly improved, the test time and energy consumption are saved, the production efficiency is improved, and the method is suitable for large-scale popularization and application.

Description

Technical Field

[0001] The present invention relates to the field of battery technology, and in particular to a battery self-discharge test method, a battery self-discharge test system, a computer device and a storage medium. Background Art

[0002] Currently, lithium-ion batteries (lithium batteries for short) undergo a crucial testing process after production and before shipment, namely the self-discharge test, to determine whether the battery meets the shipping standards.

[0003] The specific steps of the existing self-discharge test method are as follows: first, charge the battery to a preset state of charge (State of Charge, SOC for short); then, record the battery voltage value V1 at this time; then, place the battery in a specific high temperature environment, such as 45°C, and place it for a long time under this condition. The shelf time must exceed 48 hours, and this shelf time is marked as t; after the shelf time is over, measure the battery voltage value V2 again; finally, use a specific calculation formula, i.e. K=(V1-V2) / t to get the K value. If the calculated K value is lower than the established standard threshold, it means that the battery meets the quality requirements for shipment. Otherwise, if it does not meet the quality requirements for shipment, the battery will need to be further inspected or processed to ensure the performance and safety of the battery.

[0004] However, after the battery completes the above charging and load adjustment operation, the process of restoring its internal voltage to a balanced state often takes a long time, mainly because the passivation process requires sufficient time to complete. In addition, the existing battery self-discharge test method not only requires the aged battery to be left at high temperature for a long time, resulting in a large energy consumption, but also the entire test process is time-consuming, which significantly restricts production efficiency.

[0005] Therefore, in the current global context of actively advocating energy conservation and emission reduction and companies striving to reduce costs and increase efficiency, it is particularly urgent and important to explore a battery self-discharge test method that can significantly shorten the test time, ensure test efficiency and accuracy, and achieve low energy consumption.

[0006] The above information is presented as background information only to assist with understanding the present disclosure and no determination or admission is made as to whether any of the above may be used as prior art with respect to the present disclosure. Summary of the invention

[0007] The invention provides a battery self-discharge test method, a battery self-discharge test system, a computer device and a storage medium to solve the problems existing in the prior art of long test time, low test efficiency, high energy consumption and restricted production efficiency.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] In a first aspect, the present invention provides a battery self-discharge test method, the method comprising:

[0010] S1, discharging the battery to 0% SOC at a preset first rate, and standing for a preset first rest time, then charging the battery to a first target SOC at a preset second rate constant current, and standing for a preset second rest time, monitoring the voltage of the battery during the second rest time, and recording the voltage corresponding to the 0th min and the Tth min, to complete the charging and load regulation;

[0011] S2, discharging the battery after charge adjustment to 0% SOC at the first rate, then charging to the second target SOC at the second rate, and standing for the first rest time, then discharging to the first target SOC at the second rate with constant current, and standing for the second rest time, monitoring the voltage of the battery during the second rest time, and recording the voltage corresponding to the 0th min and the Tth min, to complete the discharge adjustment; the second target SOC is greater than the first target SOC;

[0012] S3, calculating and determining a corresponding first voltage drop rate according to the voltages corresponding to the 0th min and the Tth min during the second resting time in the charging and load adjustment process;

[0013] S4, calculating and determining the corresponding second voltage drop rate according to the voltages corresponding to the 0th min and the Tth min during the second resting time in the discharge charge adjustment process;

[0014] S5. Calculate and determine a self-discharge voltage drop rate according to the first voltage drop rate and the second voltage drop rate;

[0015] S6, comparing the self-discharge voltage drop rate with a preset threshold value to determine whether the self-discharge voltage drop rate is less than the threshold value; if so, executing S7, if not, executing S8;

[0016] S7, determining that the battery self-discharge rate is compliant;

[0017] S8. Determine that the battery self-discharge rate is not compliant.

[0018] Furthermore, in the battery self-discharge test method, the first rate is less than 2C;

[0019] The first standing time is 10 min-60 min;

[0020] The second ratio is 0.1C-2C;

[0021] The first target SOC is 5% SOC-20% SOC;

[0022] When the capacity of the battery is less than or equal to 10Ah, the second standing time is greater than 0.5h; when the capacity of the battery is greater than 10Ah, the second standing time is greater than 2h;

[0023] When monitoring the voltage of the battery during the second rest time, the sampling frequency is 0.1s-2s;

[0024] The Tmin is less than the second standing time;

[0025] The second target SOC is less than 100% SOC.

[0026] Further, in the battery self-discharge test method, S3 includes:

[0027] According to the voltages corresponding to the 0th min and the tth min during the second rest time in the charging and charge adjustment process, the corresponding first voltage drop rate is determined by calculation according to the following formula:

[0028] K 1 =︱(V 1-2 -V 1-1 ) / t 1 ︱;

[0029] Among them, K 1 is the first pressure drop rate; V 1-1 V is the voltage corresponding to the 0th minute during the second rest time in the charging and load adjustment process; V 1-2 is the voltage corresponding to the Tminth period during the second rest time in the charging and load adjustment process; 1 is the Tmin.

[0030] Further, in the battery self-discharge test method, step S4 comprises:

[0031] According to the voltages corresponding to the 0th min and the tth min during the second rest time in the discharge charge adjustment process, the corresponding second voltage drop rate is determined by calculation according to the following formula:

[0032] K 2 =︱(V 2-2 -V 2-1 ) / t 1 ︱;

[0033] Among them, K 2 is the second pressure drop rate; V 2-1 is the voltage corresponding to the 0th minute during the second rest time in the discharge charge adjustment process; V 2-2 is the voltage corresponding to the Tminth period during the second rest time in the discharge charge adjustment process;2 is the Tmin.

[0034] Further, in the battery self-discharge test method, S5 includes:

[0035] According to the first voltage drop rate and the second voltage drop rate, the self-discharge voltage drop rate is calculated and determined according to the following formula:

[0036] K 自 =︱(K 1 -K 2 ) / 2︱;

[0037] Among them, K 自 K is the self-discharge voltage drop rate; 1 is the first pressure drop rate; K 2 is the second pressure drop rate.

[0038] Furthermore, the battery self-discharge test method further includes, before S1, calibrating the capacity of the aged battery according to the following method:

[0039] S0.1, leaving the aged battery to stand for a third standing time;

[0040] S0.2, discharging the battery at a third rate constant current to a preset first voltage;

[0041] S0.3, let stand for the fourth standing time;

[0042] S0.4, charging the battery at the third rate constant current to a preset second voltage, and then charging at the constant current until the charging current decreases to the cut-off current;

[0043] S0.5, leaving the battery to stand for the fourth standing time;

[0044] S0.6, discharging the battery at the third rate constant current to the first voltage;

[0045] S0.7, standing for the fourth standing time;

[0046] S0.8, cycle S0.4-S0.7 until the number of cycles reaches a preset number threshold, and record the last discharged capacity as the actual capacity of the battery.

[0047] Furthermore, in the battery self-discharge test method, the third standing time is 5 minutes;

[0048] The third magnification is 0.5C;

[0049] The first voltage is 2.5V

[0050] The fourth standing time is 30 minutes;

[0051] The second voltage is 3.65V;

[0052] The cut-off current is 0.05C;

[0053] The number threshold is 2 times.

[0054] In a second aspect, the present invention provides a battery self-discharge test system, the system comprising:

[0055] A charging and load regulation module is used to discharge the battery to 0% SOC at a preset first rate, and stand for a preset first rest time, and then charge the battery to a first target SOC at a preset second rate constant current, and then stand for a preset second rest time, monitor the voltage of the battery during the second rest time, and record the voltage corresponding to the 0th min and the Tth min, to complete the charging and load regulation;

[0056] a discharge charge regulation module, for discharging the battery after charge regulation to 0% SOC at the first rate, then charging to a second target SOC at the second rate, and standing for the first rest time, then discharging to the first target SOC at the second rate with a constant current, and then standing for the second rest time, monitoring the voltage of the battery during the second rest time, and recording the voltage corresponding to the 0th min and the Tth min, to complete the discharge charge regulation; the second target SOC is greater than the first target SOC;

[0057] The calculation and judgment module is used to:

[0058] Calculate and determine the corresponding first voltage drop rate according to the voltage corresponding to the 0th min and the Tth min during the second rest time in the charging and load adjustment process;

[0059] Calculate and determine the corresponding second voltage drop rate according to the voltages corresponding to the 0th min and the Tth min during the second rest time in the discharge charge adjustment process;

[0060] Calculating and determining a self-discharge voltage drop rate according to the first voltage drop rate and the second voltage drop rate;

[0061] The self-discharge voltage drop rate is compared with a preset threshold value to determine whether the self-discharge voltage drop rate is less than the threshold value; if so, the battery self-discharge rate is determined to be compliant; if not, the battery self-discharge rate is determined to be non-compliant.

[0062] Furthermore, in the battery self-discharge test system, the first rate is less than 2C;

[0063] The first standing time is 10 min-60 min;

[0064] The second ratio is 0.1C-2C;

[0065] The first target SOC is 5% SOC-20% SOC;

[0066] When the capacity of the battery is less than or equal to 10Ah, the second standing time is greater than 0.5h; when the capacity of the battery is greater than 10Ah, the second standing time is greater than 2h;

[0067] When monitoring the voltage of the battery during the second rest time, the sampling frequency is 0.1s-2s;

[0068] The Tmin is less than the second standing time;

[0069] The second target SOC is less than 100% SOC.

[0070] Furthermore, in the battery self-discharge test system, the calculation and judgment module is specifically used for:

[0071] According to the voltages corresponding to the 0th min and the tth min during the second rest time in the charging and charge adjustment process, the corresponding first voltage drop rate is determined by calculation according to the following formula:

[0072] K 1 =︱(V 1-2 -V 1-1 ) / t 1 ︱;

[0073] Among them, K 1 is the first pressure drop rate; V 1-1 V is the voltage corresponding to the 0th minute during the second rest time in the charging and load adjustment process; V 1-2 is the voltage corresponding to the Tminth period during the second rest time in the charging and load adjustment process; 1 is the Tmin.

[0074] Furthermore, in the battery self-discharge test system, the calculation and judgment module is specifically used for:

[0075] According to the voltages corresponding to the 0th min and the tth min during the second rest time in the discharge charge adjustment process, the corresponding second voltage drop rate is determined by calculation according to the following formula:

[0076] K 2 =︱(V 2-2 -V 2-1 ) / t 1 ︱;

[0077] Among them, K 2 is the second voltage drop rate; V 2-1is the voltage corresponding to the 0th minute during the second rest time in the discharge charge adjustment process; V 2-2 is the voltage corresponding to the Tminth period during the second rest time in the discharge charge adjustment process; 2 is the Tmin.

[0078] Furthermore, in the battery self-discharge test system, the calculation and judgment module is specifically used for:

[0079] According to the first voltage drop rate and the second voltage drop rate, the self-discharge voltage drop rate is calculated and determined according to the following formula:

[0080] K 自 =︱(K 1 -K 2 ) / 2︱;

[0081] Among them, K 自 K is the self-discharge voltage drop rate; 1 is the first pressure drop rate; K 2 is the second pressure drop rate.

[0082] Furthermore, in the battery self-discharge test system, the system also includes a capacity calibration module, which is used to calibrate the capacity of the aged battery according to the following method:

[0083] S0.1. Leave the aged battery to rest for a third resting time:

[0084] S0.2, discharging the battery at a third rate constant current to a preset first voltage;

[0085] S0.3, let stand for the fourth standing time;

[0086] S0.4, charging the battery at the third rate constant current to a preset second voltage, and then charging at the constant current until the charging current decreases to the cut-off current;

[0087] S0.5, leaving the battery to stand for the fourth standing time;

[0088] S0.6, discharging the battery at the third rate constant current to the first voltage;

[0089] S0.7, standing for the fourth standing time;

[0090] S0.8, cycle S0.4-S0.7 until the number of cycles reaches a preset number threshold, and record the last discharged capacity as the actual capacity of the battery.

[0091] Furthermore, in the battery self-discharge test system, the third rest time is 5 minutes;

[0092] The third magnification is 0.5C;

[0093] The first voltage is 2.5V

[0094] The fourth standing time is 30 minutes;

[0095] The second voltage is 3.65V;

[0096] The cut-off current is 0.05C;

[0097] The number threshold is 2 times.

[0098] In a third aspect, the present invention provides a computer device, comprising a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the battery self-discharge test method provided in the first aspect is implemented.

[0099] In a fourth aspect, the present invention provides a computer-readable storage medium having computer-executable instructions stored thereon, wherein the computer-executable instructions are executed by a computer processor to implement the battery self-discharge test method provided in the first aspect above.

[0100] Compared with the prior art, the present invention has the following beneficial effects:

[0101] The present invention provides a battery self-discharge test method, a battery self-discharge test system, a computer device and a storage medium. The method first charges and adjusts the charge to a first target SOC, and then discharges and adjusts the charge to the first target SOC. The two charge adjustment methods have the same passivation speed, but the voltage rebound directions of the passivation process are opposite, so that the passivation of the two charge adjustment methods can be subtracted and offset. Then, according to the voltage monitored during the static period under the two charge adjustment methods, the self-discharge voltage drop rate of the battery is calculated and determined to determine whether the self-discharge rate of the battery is compliant, thereby not only ensuring higher test accuracy, but also greatly improving the test efficiency, saving test time and energy consumption, which is conducive to improving production efficiency and suitable for large-scale promotion and application.

[0102] The present invention has other features and advantages, which will be apparent from or will be described in detail in the accompanying drawings and the following detailed description incorporated herein, which together serve to explain the specific principles of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0103] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0104] Figure 1 It is a flowchart of a battery self-discharge test method provided in Embodiment 1 of the present invention;

[0105] Figure 2 This is a data schematic diagram of charging and load regulation provided in the first embodiment of the present invention;

[0106] Figure 3 This is a data schematic diagram of discharge charge regulation provided by the first embodiment of the present invention;

[0107] Figure 4 This is a graph showing the deterioration of batteries with different capacities at 25°C provided in Example 1 of the present invention.

[0108] Figure 5 The self-discharge voltage drop rate K of 10 batteries provided in the first embodiment of the present invention is 自 Schematic diagram of box plot processing;

[0109] Figure 6 The self-discharge voltage drop rate K of 100 aged 70Ah LFPs according to the new method provided in Example 1 of the present invention is 自 Schematic diagram of box plot processing;

[0110] Figure 7 The self-discharge voltage drop rate K of 100 aged 72Ah NCM aluminum shell batteries according to the new method provided in Example 1 of the present invention is 自 Schematic diagram of box plot processing;

[0111] Figure 8 is the self-discharge voltage drop rate K of 3000 aged 70Ah LFPs provided in Example 1 of the present invention according to conventional methods 自 Schematic diagram of box plot processing;

[0112] Fig. 9 is the self-discharge voltage drop rate K of 3000 aged 72Ah NCM aluminum shell batteries provided in Example 1 of the present invention according to the conventional method 自 Schematic diagram of box plot processing;

[0113] Fig.10 is a schematic diagram of a process for calibrating the capacity of an aged battery provided in the first embodiment of the present invention;

[0114] Fig.11This is a functional module diagram of a battery self-discharge test system provided by Embodiment 2 of the present invention;

[0115] Fig.12 It is a structural diagram of a computer device provided in Embodiment 3 of the present invention. DETAILED DESCRIPTION

[0116] In order to explain in detail the possible application scenarios, technical principles, specific schemes that can be implemented, and the purposes and effects that can be achieved, the following is a detailed description of the specific embodiments listed in conjunction with the accompanying drawings. The embodiments described herein are only used to more clearly illustrate the technical solutions of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0117] Reference to "embodiment" herein means that the specific features, structures or characteristics described in conjunction with the embodiment may be included in at least one embodiment of the present application. The term "embodiment" appearing in various places in the specification does not necessarily refer to the same embodiment, nor does it particularly limit its independence or association with other embodiments. In principle, in the present application, as long as there is no technical contradiction or conflict, the various technical features mentioned in the embodiments can be combined in any way to form a corresponding implementable technical solution.

[0118] Unless otherwise defined, the technical terms used in this document have the same meanings as those generally understood by those skilled in the art to which this application belongs; the use of relevant terms in this document is only for describing specific embodiments and is not intended to limit this application.

[0119] In the description of this application, the term "and / or" is an expression used to describe the logical relationship between objects, indicating that three relationships may exist, for example, A and / or B, which means: A exists, B exists, and A and B exist at the same time. In addition, the character " / " in this article generally indicates that the objects before and after are in an "or" logical relationship.

[0120] In the present application, terms such as “first” and “second” are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship of quantity, priority or sequence between these entities or operations.

[0121] Without further limitations, in this application, the words "include", "comprises", "has" or other similar expressions used in the sentences are intended to cover non-exclusive inclusion. These expressions do not exclude the presence of additional elements in the process, method or product including the elements, so that the process, method or product including a series of elements may include not only those limited elements, but also other elements not explicitly listed, or also include elements inherent to such process, method or product.

[0122] In this application, expressions such as "greater than", "less than", "exceed" and the like are understood to exclude the number itself; expressions such as "above", "below", "within" and the like are understood to include the number itself. In addition, in the description of the embodiments of this application, "multiple" means more than two (including two), and similar expressions related to "multiple" are also understood in this way, such as "multiple groups", "multiple times", etc., unless otherwise clearly and specifically limited.

[0123] In the description of the embodiments of the present application, space-related expressions used, such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "vertical", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicate the orientation or position relationship based on the orientation or position relationship shown in the specific embodiments or drawings, and are only for the convenience of describing the specific embodiments of the present application or facilitating the reader's understanding, and do not indicate or imply that the referred device or component must have a specific position, a specific orientation, or be constructed or operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0124] Unless otherwise expressly specified or limited, in the description of the embodiments of the present application, the terms such as "install", "connect", "connect", "fix", "set", etc. used should be understood in a broad sense. For example, the "connection" can be a fixed connection, a detachable connection, or an integrated setting; it can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. For technicians in the technical field to which the present application belongs, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0125] Embodiment 1

[0126] Please refer to Figure 1 , is a flow chart of a battery self-discharge test method provided in Embodiment 1 of the present invention, which is applicable to the scenario of performing a self-discharge test on a battery. The method specifically comprises the following steps:

[0127] S1. Discharge the battery to 0% SOC at a preset first rate, and let it stand for a preset first rest time, then charge it to a first target SOC at a preset second rate constant current, and let it stand for a preset second rest time, monitor the voltage of the battery during the second rest time, and record the voltage corresponding to the 0th min and the Tth min, to complete the charging and load adjustment.

[0128] It should be noted that the data diagram of charging and load regulation is as follows Figure 2 shown.

[0129] The first magnification is less than 2C, that is, a value can be selected arbitrarily within the range of 0C-2C (excluding 0C and 2C) according to actual conditions as the first magnification;

[0130] The first standing time is 10 min-60 min, and a value can be arbitrarily selected within the range of 10 min-60 min according to actual conditions as the first standing time;

[0131] The second magnification is 0.1C-2C, and a value can be selected arbitrarily within the range of 0.1C-2C according to actual conditions as the second magnification;

[0132] The first target SOC is 5% SOC-20% SOC, and a value can be selected arbitrarily within the range of 5% SOC-20% SOC as the first target SOC according to actual conditions;

[0133] When the capacity of the battery is less than or equal to 10Ah, the second resting time is greater than 0.5h, and a value can be selected arbitrarily within the range of 0.5h-∞ (excluding 0.5h) according to actual conditions as the second resting time;

[0134] When the capacity of the battery is greater than 10Ah, the second resting time is greater than 2h, and a value can be selected arbitrarily within the range of 2h-∞ (excluding 2h) according to actual conditions as the second resting time;

[0135] When monitoring the voltage of the battery during the second rest time, the sampling frequency is 0.1s-2s, and a value can be selected arbitrarily within the range of 0.1s-2s according to actual conditions as the sampling frequency;

[0136] The Tmin is less than the second standing time.

[0137] S2. Discharge the battery after charge adjustment to 0% SOC at the first rate, then charge to the second target SOC at the second rate, and let it stand for the first rest time, then discharge to the first target SOC at the second rate with constant current, and let it stand for the second rest time, monitor the voltage of the battery during the second rest time, and record the voltages corresponding to 0min and Tmin, to complete the discharge adjustment; the second target SOC is greater than the first target SOC.

[0138] It should be noted that the data diagram of discharge charge regulation is as follows Figure 3 shown.

[0139] The same features in S2 as those in S1 are explained in the same way as in S1 and will not be described in detail here.

[0140] In addition to being greater than the first target SOC, the second target SOC is also less than 100% SOC.

[0141] The speed of battery degeneration is related to battery capacity, temperature and battery system. Under the same capacity, the degeneration speed of ternary lithium-ion batteries is faster than that of lithium iron phosphate (LFP) lithium-ion batteries; for the same system, the higher the temperature and the lower the capacity, the faster the degeneration speed. The definition of the above-mentioned standing time and Tmin is as follows:

[0142] (1) The standing time is the time required for a certain type of battery to completely deactivate at a certain temperature;

[0143] (2) Tmin is less than the static time, which is generally based on the initial time of battery passivation completion; the so-called "initial time of battery passivation completion" refers to the stage when the battery voltage begins to stabilize over time, that is, the stage when the voltage change is extremely small. At this stage, Tmin can be set; in addition, you can also refer to the Figure 2 , Figure 3 , Figure 4 When dV / dt≤0.001, it can be considered that the voltage change rate (i.e., the derivative of voltage with respect to time) is close to 0.001. At this time, Tmin can be taken, that is, the ratio of voltage to time is close to 0.001. It should be noted that the threshold value "0.001" can be appropriately adjusted according to actual conditions and is allowed to fluctuate within a certain range.

[0144] (3) The following table shows the specific time T and the static time required for deactivation of LFP batteries of different capacities after charging at 1C at 25°C;

[0145]

[0146] (4) For ternary lithium batteries with similar capacity, their standing time and T can refer to those of LFP batteries.

[0147] Figure 4 The degeneration curve of batteries with different capacities at 25°C.

[0148] S3. Calculate and determine a corresponding first voltage drop rate according to the voltages corresponding to the 0th min and the Tth min during the second resting time in the charging and load adjustment process.

[0149] It should be noted that the first voltage drop rate is calculated based on the voltage values ​​corresponding to the 0th and Tth min during the second resting time in the charging and load adjustment process, and the voltage drop rate of the battery during this period is the first voltage drop rate. This voltage drop rate reflects the voltage stability of the battery during the resting period after charging.

[0150] In one implementation of this embodiment, the S3 may be further refined to include the following steps:

[0151] According to the voltages corresponding to the 0th min and the tth min during the second rest time in the charging and charge adjustment process, the corresponding first voltage drop rate is determined by calculation according to the following formula:

[0152] K 1 =︱(V 1-2 -V 1-1 ) / t 1 ︱;

[0153] Among them, K 1 is the first pressure drop rate; V 1-1 V is the voltage corresponding to the 0th minute during the second rest time in the charging and load adjustment process; V 1-2 is the voltage corresponding to the Tminth period during the second rest time in the charging and load adjustment process; 1 is the Tmin.

[0154] The unit of K value is mV / h. When calculating, Tmin needs to be converted to T′h.

[0155] S4. Calculate and determine the corresponding second voltage drop rate according to the voltages corresponding to the 0th min and the Tth min during the second resting time in the discharge charge adjustment process.

[0156] It should be noted that the second voltage drop rate is calculated based on the voltage values ​​corresponding to the 0th and Tth min during the second resting time in the discharge and charge adjustment process, and the voltage drop rate of the battery during this period is the second voltage drop rate. This voltage drop rate reflects the voltage stability of the battery during the resting period after discharge.

[0157] In one implementation of this embodiment, the S5 may be further refined to include the following steps:

[0158] According to the voltages corresponding to the 0th min and the tth min during the second rest time in the discharge charge adjustment process, the corresponding second voltage drop rate is determined by calculation according to the following formula:

[0159] K 2 =︱(V 2-2 -V 2-1 ) / t 1 ︱;

[0160] Among them, K 2 is the second voltage drop rate; V 2-1 is the voltage corresponding to the 0th minute during the second rest time in the discharge charge adjustment process; V 2-2 is the voltage corresponding to the Tminth period during the second rest time in the discharge charge adjustment process; 2 is the Tmin.

[0161] The unit of K value is mV / h. When calculating, Tmin needs to be converted to T′h.

[0162] S5. Calculate and determine the self-discharge voltage drop rate according to the first voltage drop rate and the second voltage drop rate.

[0163] In one implementation of this embodiment, the S5 may be further refined to include the following steps:

[0164] According to the first voltage drop rate and the second voltage drop rate, the self-discharge voltage drop rate is calculated and determined according to the following formula:

[0165] K 自 =︱(K 1 -K 2 ) / 2︱;

[0166] Among them, K 自 K is the self-discharge voltage drop rate; 1 is the first pressure drop rate; K 2 is the second pressure drop rate.

[0167] S6. Compare the self-discharge voltage drop rate with a preset threshold value to determine whether the self-discharge voltage drop rate is less than the threshold value; if so, execute S7; if not, execute S8.

[0168] It should be noted that the self-discharge voltage drop rate is an indicator that measures the rate at which the battery voltage drops due to self-discharge during static conditions. It is calculated using a specific test method and reflects the quality of the battery's self-discharge performance.

[0169] Preset threshold: This is a pre-set standard value used to determine whether the battery's self-discharge voltage drop rate meets specific requirements or standards. This threshold is usually set by technicians based on experience and factors such as the battery type, purpose, and performance requirements. It is based on specific experimental results and can be any value.

[0170] The purpose of this comparison step is to determine whether the self-discharge performance of the battery meets the expected standards or requirements.

[0171] S7. Determine whether the battery self-discharge rate is compliant.

[0172] It should be noted that if the self-discharge voltage drop rate is less than the preset threshold, it means that the voltage drop rate of the battery during the static period is low, the self-discharge performance is good, and meets or exceeds the expected standard.

[0173] S8. Determine that the battery self-discharge rate is not compliant.

[0174] It should be noted that if the self-discharge voltage drop rate is not less than the preset threshold (i.e. greater than or equal to the threshold), this means that the battery voltage drop rate during the static period is high, the self-discharge performance is poor, and does not meet the expected standard. Further testing, adjustment or replacement may be required.

[0175] In one implementation of this embodiment, before S1, the capacity of the aged battery is calibrated according to the following method: Fig.10 As shown:

[0176] S0.1, leaving the aged battery to stand for a third standing time;

[0177] S0.2, discharging the battery at a third rate constant current to a preset first voltage;

[0178] S0.3, let stand for the fourth standing time;

[0179] S0.4, charging the battery at the third rate constant current to a preset second voltage, and then charging at the constant current until the charging current decreases to the cut-off current;

[0180] S0.5, leaving the battery to stand for the fourth standing time;

[0181] S0.6, discharging the battery at the third rate constant current to the first voltage;

[0182] S0.7, standing for the fourth standing time;

[0183] S0.8, cycle S0.4-S0.7 until the number of cycles reaches a preset number threshold, and record the last discharged capacity as the actual capacity of the battery.

[0184] It should be noted that the third standing time is 5 minutes;

[0185] The third magnification is 0.5C;

[0186] The first voltage is 2.5V

[0187] The fourth standing time is 30 minutes;

[0188] The second voltage is 3.65V;

[0189] The cut-off current is 0.05C;

[0190] The number threshold is 2 times.

[0191] In order to fully verify the feasibility and practicality of the content proposed in this embodiment, this embodiment has selected a detailed example for in-depth analysis and specific elaboration. This example not only shows every link of the implementation steps in detail, but also strongly proves the effectiveness and reliability of the method described in this embodiment through the actual operation process. Through the detailed display of this example, it is intended to be able to understand the core ideas and technical points of this embodiment more intuitively and comprehensively, so as to further believe in its great potential and broad prospects in practical applications.

[0192] 1. Capacity calibration: Take 10 aged soft-pack LFP batteries (nominal capacity is 3.45Ah) and load them onto the machine. First, perform capacity calibration and obtain the actual capacity C0 (Ah) of the battery.

[0193] 2. Charging and load adjustment: Charge the battery after constant capacity at a rate of 1C0 (charge and discharge rate = charge and discharge current / rated capacity, 1C0 means that the capacity can be fully charged and discharged in 1 hour) for 10.2 minutes. At this time, the battery capacity is 17% SOC (the amount of electricity required for the company's battery shipment). Then, let the battery stand for 2 hours and record the battery voltage at 0 minute and 20 minutes.

[0194] 3. Discharge and load adjustment: The battery that has been left to stand after charge and load adjustment is discharged to 2.5V at 0.5C0 current and left to stand for 30 minutes. Then, the battery is charged at 1C0 current for 16.2 minutes. At this time, the battery capacity is 27% SOC. The battery is left to stand for 5 minutes, and then discharged at 1C0 current for 6 minutes. At this time, the battery capacity is 17% SOC. The battery is left to stand for 2 hours and the battery voltage at 0min and 20min is recorded.

[0195] 3. K value calculation: The voltage recorded during the charge adjustment and static period is recorded as VC0 and VC20 respectively; the voltage recorded during the discharge adjustment and static period is recorded as VD0 and VD20, and the K value (K) of the charge adjustment and static period is obtained. 1=︱(VC20-VC0) / (20 / 60)︱) and the K value of discharge charge adjustment static (K 2 =︱(VD20-VD0) / (20 / 60)︱);

[0196] 4. Self-discharge voltage drop rate K 自 Calculation: Substitute the K value calculated above into the formula: K 自 =︱(K 1 -K 2 ) / 2︱, and the self-discharge voltage drop rate K for 20 minutes is obtained. 自 The specific calculation results are as follows:

[0197]

[0198] And the self-discharge voltage drop rate K of 10 batteries 自 Do box plot processing, such as Figure 5 shown.

[0199] It can be seen from the test results that for small-capacity batteries (≤4Ah), this method can calculate the battery self-discharge voltage drop rate in a relatively short time, and its test data are distributed in the same range.

[0200] In order to further confirm the reliability of this method, 100 aged 70Ah LFP and 72Ah NCM aluminum shell batteries were taken from the production line and tested again according to the above steps. The data was processed and box plotted. The self-discharge results after 60 minutes of standing are as follows: Figure 6-7 As shown;

[0201] It can be seen from the box plot that the K value distribution of LFP aluminum shell batteries is consistent with the distribution range of LFP soft pack batteries (the K value standard of its production line is ≤0.025mV / h), indicating that this method is used to calculate the battery K value with high accuracy, and can effectively avoid the mistaken killing of qualified batteries due to large K values ​​caused by inaccurate equipment monitoring, or the missed killing of unqualified batteries due to large K values.

[0202] Compare the same batch of batteries (3000) with the self-discharge test performed by conventional methods, and make a box plot of the results. Figure 8-9 As shown;

[0203] From the results of the new method and the conventional method for LFP aluminum shell batteries and NCM aluminum shell batteries, the K value data intervals obtained by the two methods are consistent, and the K values ​​calculated by the new method (where the K value standard for LFP batteries in the production line is ≤0.025mV / h, and the K value standard for NCM batteries is ≤0.030mV / h) are concentrated with fewer outliers. The data shows that for batteries of different systems, the calculated K values ​​of this method are consistent with the data of the existing methods and have high accuracy, which effectively avoids missed kills and false kills caused by inaccurate calculation of K values ​​due to low accuracy of monitoring equipment.

[0204] From the above results, it can be seen that the data obtained by the self-discharge test using this method is accurate compared with the results of the traditional method. It can also effectively avoid over-killing, missed killing, and short use time caused by large K values ​​to a certain extent, greatly reduce energy consumption and improve production line utilization.

[0205] Although the terms such as charge regulation, self-discharge, and capacity are used more frequently in this application, the possibility of using other terms is not excluded. These terms are used only to more conveniently describe and explain the essence of the present invention; interpreting them as any additional restrictions is contrary to the spirit of the present invention.

[0206] A battery self-discharge test method provided by an embodiment of the present invention first charges and adjusts the charge to a first target SOC, and then discharges and adjusts the charge to a first target SOC. The two charge adjustment methods have the same passivation speed, but the voltage rebound direction of the passivation process is opposite, so that the passivation of the two charge adjustment methods can be subtracted and offset. Then, according to the voltage monitored during the static period under the two charge adjustment methods, the self-discharge voltage drop rate of the battery is calculated and determined to determine whether the self-discharge rate of the battery is compliant, thereby not only ensuring higher test accuracy, but also greatly improving test efficiency, saving test time and energy consumption, which is conducive to improving production efficiency and is suitable for large-scale promotion and application.

[0207] Embodiment 2

[0208] Please refer to Fig.11 Embodiment 2 of the present invention provides a battery self-discharge test system, the system comprising:

[0209] The charging and load regulation module 201 is used to discharge the battery to 0% SOC at a preset first rate, and let it stand for a preset first rest time, and then charge it to a first target SOC at a preset second rate constant current, and then let it stand for a preset second rest time, monitor the voltage of the battery during the second rest time, and record the voltage corresponding to the 0th min and the Tth min, to complete the charging and load regulation;

[0210] The discharge charge regulation module 202 is used to discharge the battery after the charge regulation to 0% SOC at the first rate, then charge to the second target SOC at the second rate, and stand for the first rest time, then discharge to the first target SOC at the second rate constant current, and then stand for the second rest time, monitor the voltage of the battery during the second rest time, and record the voltage corresponding to the 0th min and the Tth min, to complete the discharge charge regulation; the second target SOC is greater than the first target SOC;

[0211] The calculation and judgment module 203 is used to:

[0212] Calculate and determine the corresponding first voltage drop rate according to the voltage corresponding to the 0th min and the Tth min during the second rest time in the charging and load adjustment process;

[0213] Calculate and determine the corresponding second voltage drop rate according to the voltages corresponding to the 0th min and the Tth min during the second rest time in the discharge charge adjustment process;

[0214] Calculating and determining a self-discharge voltage drop rate according to the first voltage drop rate and the second voltage drop rate;

[0215] The self-discharge voltage drop rate is compared with a preset threshold value to determine whether the self-discharge voltage drop rate is less than the threshold value; if so, the battery self-discharge rate is determined to be compliant; if not, the battery self-discharge rate is determined to be non-compliant.

[0216] Preferably, in the battery self-discharge test system, the first rate is less than 2C;

[0217] The first standing time is 10 min-60 min;

[0218] The second ratio is 0.1C-2C;

[0219] The first target SOC is 5% SOC-20% SOC;

[0220] When the capacity of the battery is less than or equal to 10Ah, the second standing time is greater than 0.5h; when the capacity of the battery is greater than 10Ah, the second standing time is greater than 2h;

[0221] When monitoring the voltage of the battery during the second rest time, the sampling frequency is 0.1s-2s;

[0222] The Tmin is less than the second standing time;

[0223] The second target SOC is less than 100% SOC.

[0224] Preferably, in the battery self-discharge test system, the calculation and judgment module 203 is specifically used for:

[0225] According to the voltages corresponding to the 0th min and the tth min during the second rest time in the charging and charge adjustment process, the corresponding first voltage drop rate is determined by calculation according to the following formula:

[0226] K 1 =︱(V 1-2 -V 1-1 ) / t 1 ︱;

[0227] Among them, K 1 is the first pressure drop rate; V 1-1 V is the voltage corresponding to the 0th minute during the second rest time in the charging and load adjustment process; V 1-2 is the voltage corresponding to the Tminth period during the second rest time in the charging and load adjustment process; 1 is the Tmin.

[0228] Preferably, in the battery self-discharge test system, the calculation and judgment module 203 is specifically used for:

[0229] According to the voltages corresponding to the 0th min and the tth min during the second rest time in the discharge charge adjustment process, the corresponding second voltage drop rate is determined by calculation according to the following formula:

[0230] K 2 =︱(V 2-2 -V 2-1 ) / t 1 ︱;

[0231] Among them, K 2 is the second voltage drop rate; V 2-1 is the voltage corresponding to the 0th minute during the second rest time in the discharge charge adjustment process; V 2-2 is the voltage corresponding to the Tminth period during the second rest time in the discharge charge adjustment process; 2 is the Tmin.

[0232] Preferably, in the battery self-discharge test system, the calculation and judgment module 203 is specifically used for:

[0233] According to the first voltage drop rate and the second voltage drop rate, the self-discharge voltage drop rate is calculated and determined according to the following formula:

[0234] K 自 =︱(K 1 -K 2 ) / 2︱;

[0235] Among them, K自 K is the self-discharge voltage drop rate; 1 is the first pressure drop rate; K 2 is the second pressure drop rate.

[0236] Preferably, in the battery self-discharge test system, the system further includes a capacity calibration module, which is used to calibrate the capacity of the aged battery according to the following method:

[0237] S0.1, leaving the aged battery to stand for a third standing time;

[0238] S0.2, discharging the battery at a third rate constant current to a preset first voltage;

[0239] S0.3, let stand for the fourth standing time;

[0240] S0.4, charging the battery at the third rate constant current to a preset second voltage, and then charging at the constant current until the charging current decreases to the cut-off current;

[0241] S0.5, leaving the battery to stand for the fourth standing time;

[0242] S0.6, discharging the battery at the third rate constant current to the first voltage;

[0243] S0.7, standing for the fourth standing time;

[0244] S0.8, cycle S0.4-S0.7 until the number of cycles reaches a preset number threshold, and record the last discharged capacity as the actual capacity of the battery.

[0245] Preferably, in the battery self-discharge test system, the third standing time is 5 minutes;

[0246] The third magnification is 0.5C;

[0247] The first voltage is 2.5V

[0248] The fourth standing time is 30 minutes;

[0249] The second voltage is 3.65V;

[0250] The cut-off current is 0.05C;

[0251] The number threshold is 2 times.

[0252] A battery self-discharge test system provided by an embodiment of the present invention first charges and adjusts the charge to a first target SOC, and then discharges and adjusts the charge to a first target SOC. The passivation speeds of the two charge adjustment methods are the same, but the voltage rebound directions of the passivation process are opposite, so that the passivation of the two charge adjustment methods can be subtracted and offset. Then, according to the voltage monitored during the static period under the two charge adjustment methods, the self-discharge voltage drop rate of the battery is calculated and determined to determine whether the self-discharge rate of the battery is compliant, thereby not only ensuring higher test accuracy, but also greatly improving test efficiency, saving test time and energy consumption, which is conducive to improving production efficiency and is suitable for large-scale promotion and application.

[0253] The above system can execute the method provided by any embodiment of the present invention, and has the corresponding functional modules and beneficial effects of the execution method.

[0254] Embodiment 3

[0255] Fig.12 A schematic diagram of the structure of a computer device provided in Embodiment 3 of the present invention. Fig.12 A block diagram of an exemplary computer device 12 suitable for use in implementing embodiments of the present invention is shown. Fig.12 The computer device 12 shown is only an example and should not bring any limitation to the functions and scope of use of the embodiments of the present invention.

[0256] like Fig.12 As shown, the computer device 12 is in the form of a general-purpose computing device. The components of the computer device 12 may include, but are not limited to: one or more processors or processing units 16, a system memory 28, and a bus 18 that connects various system components (including the system memory 28 and the processing unit 16).

[0257] Bus 18 represents one or more of several types of bus structures, including a memory bus or memory controller, a peripheral bus, an accelerated graphics port, a processor or a local bus using any of a variety of bus architectures. By way of example, these architectures include, but are not limited to, an Industry Standard Architecture (ISA) bus, a Micro Channel Architecture (MAC) bus, an Enhanced ISA bus, a Video Electronics Standards Association (VESA) local bus, and a Peripheral Component Interconnect (PCI) bus.

[0258] The computer device 12 typically includes a variety of computer system readable media. These media can be any available media that can be accessed by the computer device 12, including volatile and non-volatile media, removable and non-removable media.

[0259] The system memory 28 may include computer system readable media in the form of volatile memory, such as random access memory (RAM) 30 and / or cache memory 32. The computer device 12 may further include other removable / non-removable, volatile / non-volatile computer system storage media. By way of example only, the storage system 34 may be used to read and write non-removable, non-volatile magnetic media ( Fig.12 not shown, usually called a "hard drive"). Although Fig.12 Not shown in the figure, a disk drive for reading and writing to a removable non-volatile disk (e.g., a "floppy disk"), and an optical disk drive for reading and writing to a removable non-volatile optical disk (e.g., a CD-ROM, a DVD-ROM, or other optical media) may be provided. In these cases, each drive may be connected to the bus 18 via one or more data medium interfaces. The memory 28 may include at least one program product having a set (e.g., at least one) of program modules that are configured to perform the functions of the various embodiments of the present invention.

[0260] A program / utility 40 having a set (at least one) of program modules 42 may be stored, for example, in the memory 28, such program modules 42 including but not limited to an operating system, one or more application programs, other program modules, and program data, each of which or some combination may include an implementation of a network environment. The program modules 42 generally perform the functions and / or methods of the embodiments described herein.

[0261] The computer device 12 may also communicate with one or more external devices 14 (e.g., keyboards, pointing devices, displays 24, etc.), one or more devices that enable a user to interact with the computer device 12, and / or any device that enables the computer device 12 to communicate with one or more other computing devices (e.g., a network card, a modem, etc.). Such communication may be performed via an input / output (I / O) interface 22. In addition, the computer device 12 may also communicate with one or more networks (e.g., a local area network (LAN), a wide area network (WAN), and / or a public network, such as the Internet) via a network adapter 20. As shown, the network adapter 20 communicates with the other modules of the computer device 12 via a bus 18. It should be understood that although Fig.12 Not shown, other hardware and / or software modules may be used in conjunction with computer device 12, including but not limited to microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage systems.

[0262] The processing unit 16 executes various functional applications and data processing by running the programs stored in the system memory 28, such as implementing the battery self-discharge test method provided in the embodiment of the present invention.

[0263] Embodiment 4

[0264] Embodiment 4 of the present invention provides a computer-readable storage medium on which computer-executable instructions are stored. When the instructions are executed by a processor, the battery self-discharge test method provided in all the embodiments of the present application is implemented.

[0265] Any combination of one or more computer-readable media may be used. A computer-readable medium may be a computer-readable signal medium or a computer-readable storage medium. A computer-readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, or device, or any combination thereof. More specific examples (a non-exhaustive list) of computer-readable storage media include: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof. In this document, a computer-readable storage medium may be any tangible medium containing or storing a program that may be used by or in conjunction with an instruction execution system, device, or device.

[0266] Computer-readable signal media may include data signals propagated in baseband or as part of a carrier wave, which carry computer-readable program code. Such propagated data signals may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. Computer-readable signal media may also be any computer-readable medium other than a computer-readable storage medium, which may send, propagate, or transmit a program for use by or in conjunction with an instruction execution system, apparatus, or device.

[0267] Program code embodied on a computer readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing.

[0268] Computer program code for performing the operations of the present invention may be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, C++, and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the user's computer, partially on the user's computer, as a separate software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., through the Internet using an Internet service provider).

[0269] Finally, it should be noted that although the above embodiments have been described in the specification and drawings of this application, this does not limit the scope of patent protection of this application. All technical solutions generated by replacing or modifying equivalent structures or equivalent processes based on the essential concept of this application using the contents recorded in the specification and drawings of this application, as well as directly or indirectly implementing the technical solutions of the above embodiments in other related technical fields, are included in the scope of patent protection of this application.

Claims

1. A battery self-discharge test method, characterized in that: The method comprises: S1, discharging the battery to 0% SOC at a preset first rate, and standing for a preset first rest time, then charging the battery to a first target SOC at a preset second rate constant current, and standing for a preset second rest time, monitoring the voltage of the battery during the second rest time, and recording the voltage corresponding to the 0th min and the Tth min, to complete the charging and load regulation; S2, discharging the battery after charge adjustment to 0% SOC at the first rate, then charging to the second target SOC at the second rate, and standing for the first rest time, then discharging to the first target SOC at the second rate with constant current, and standing for the second rest time, monitoring the voltage of the battery during the second rest time, and recording the voltage corresponding to the 0th min and the Tth min, to complete the discharge adjustment; the second target SOC is greater than the first target SOC; S3, calculating and determining a corresponding first voltage drop rate according to the voltages corresponding to the 0th min and the Tth min during the second rest time in the charging and load adjustment process; S4, calculating and determining the corresponding second voltage drop rate according to the voltages corresponding to the 0th min and the Tth min during the second resting time in the discharge charge adjustment process; S5. Calculate and determine a self-discharge voltage drop rate according to the first voltage drop rate and the second voltage drop rate; S6, comparing the self-discharge voltage drop rate with a preset threshold value to determine whether the self-discharge voltage drop rate is less than the threshold value; if so, executing S7, if not, executing S8; S7, determining that the battery self-discharge rate is compliant; S8. Determine that the battery self-discharge rate is not compliant.

2. The battery self-discharge test method according to claim 1, characterized in that: The first magnification is less than 2C; The first standing time is 10 min-60 min; The second ratio is 0.1C-2C; The first target SOC is 5% SOC-20% SOC; When the capacity of the battery is less than or equal to 10Ah, the second standing time is greater than 0.5h; when the capacity of the battery is greater than 10Ah, the second standing time is greater than 2h; When monitoring the voltage of the battery during the second rest time, the sampling frequency is 0.1s-2s; The Tmin is less than the second standing time; The second target SOC is less than 100% SOC.

3. The battery self-discharge test method according to claim 2, characterized in that: The S3 includes: According to the voltages corresponding to the 0th min and the tth min during the second rest time in the charging and charge adjustment process, the corresponding first voltage drop rate is determined by calculation according to the following formula: K1=︱(V 1-2 -V 1-1 ) / t1︱; Wherein, K1 is the first voltage drop rate; V 1-1 V is the voltage corresponding to the 0th minute during the second rest time in the charging and load adjustment process; V 1-2 is the voltage corresponding to Tmin during the second rest time in the charging and charge adjustment process; t1 is the Tmin.

4. The battery self-discharge test method according to claim 1, characterized in that: The step S4 comprises: According to the voltages corresponding to the 0th min and the tth min during the second rest time in the discharge charge adjustment process, the corresponding second voltage drop rate is determined by calculation according to the following formula: K2=|(V 2-2 -V 2-1 ) / t2|; Wherein, K2 is the second voltage drop rate; V 2-1 is the voltage corresponding to the 0th minute during the second rest time in the discharge charge adjustment process; V 2-2 is the voltage corresponding to Tmin during the second rest time in the discharge charge adjustment process; t2 is the Tmin.

5. The battery self-discharge testing method according to claim 1, characterized in that: The S5 includes: According to the first voltage drop rate and the second voltage drop rate, the self-discharge voltage drop rate is calculated and determined according to the following formula: |K 自 =(K1-K2) / 2|; Among them, K 自 is the self-discharge voltage drop rate; K1 is the first voltage drop rate; K2 is the second voltage drop rate.

6. The battery self-discharge testing method according to claim 1, characterized in that: Before S1, the capacity of the aged battery is calibrated as follows: S0.1, leaving the aged battery to stand for a third standing time; S0.2, discharging the battery at a third rate constant current to a preset first voltage; S0.3, let stand for the fourth standing time; S0.4, charging the battery at the third rate constant current to a preset second voltage, and then charging at the constant current until the charging current decreases to the cut-off current; S0.5, leaving the battery to stand for the fourth standing time; S0.6, discharging the battery at the third rate constant current to the first voltage; S0.7, standing for the fourth standing time; S0.8, cycle S0.4-S0.7 until the number of cycles reaches a preset number threshold, and record the last discharged capacity as the actual capacity of the battery.

7. The battery self-discharge test method according to claim 6, wherein the third standing time is 5 minutes; The third magnification is 0.5C; The first voltage is 2.5V The fourth standing time is 30 minutes; The second voltage is 3.65V; The cut-off current is 0.05C; The number threshold is 2 times.

8. A battery self-discharge test system, characterized in that: The system comprises: A charging and load regulation module is used to discharge the battery to 0% SOC at a preset first rate, and stand for a preset first rest time, and then charge the battery to a first target SOC at a preset second rate constant current, and then stand for a preset second rest time, monitor the voltage of the battery during the second rest time, and record the voltage corresponding to the 0th min and the Tth min, to complete the charging and load regulation; a discharge charge regulation module, for discharging the battery after charge regulation to 0% SOC at the first rate, then charging to a second target SOC at the second rate, and standing for the first rest time, then discharging to the first target SOC at the second rate with a constant current, and then standing for the second rest time, monitoring the voltage of the battery during the second rest time, and recording the voltage corresponding to the 0th min and the Tth min, to complete the discharge charge regulation; the second target SOC is greater than the first target SOC; The calculation and judgment module is used to: Calculate and determine the corresponding first voltage drop rate according to the voltage corresponding to the 0th min and the Tth min during the second rest time in the charging and load adjustment process; Calculate and determine the corresponding second voltage drop rate according to the voltages corresponding to the 0th min and the Tth min during the second rest time in the discharge charge adjustment process; Calculating and determining a self-discharge voltage drop rate according to the first voltage drop rate and the second voltage drop rate; The self-discharge voltage drop rate is compared with a preset threshold value to determine whether the self-discharge voltage drop rate is less than the threshold value; if so, the battery self-discharge rate is determined to be compliant; if not, the battery self-discharge rate is determined to be non-compliant.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the battery self-discharge testing method according to any one of claims 1 to 7 is implemented.

10. A computer-readable storage medium having computer-executable instructions stored thereon, characterized in that: The computer executable instructions are executed by a computer processor to implement the battery self-discharge testing method according to any one of claims 1 to 7.

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