Battery cell gas production rate detection method, battery pack fault detection method, equipment and medium

Abstract

The invention relates to the technical field of batteries, particularly provides a battery cell gas production rate detection method, a battery pack fault detection method, equipment and a medium, and aims to solve the technical problem that the existing method cannot accurately detect the gas production rate of a battery cell. The method for detecting the gas production rate of the battery cell comprises the following steps: determining the positive pole capacity loss and the negative pole capacity loss of the battery cell; establishing a function relationship between the positive electrode gas production rate of the battery cell and the positive electrode capacity loss, and a function relationship between the negative electrode gas production rate of the battery cell and the negative electrode capacity loss; and determining the cell gas yield based on the positive capacity loss, the negative capacity loss, the function relationship between the positive gas yield of the cell and the positive capacity loss, and the function relationship between the negative gas yield of the cell and the negative capacity loss. Therefore, the high-accuracy gas production rate of the battery cell is obtained, and the detection precision of the gas production rate of the battery cell is improved.

Description

Technical Field

[0001] The present invention relates to the field of battery technology, and specifically provides a method for detecting gas production of a battery cell, a method, device and medium for detecting battery pack faults. Background Art

[0002] At present, the amount of gas produced by highly doped silicon-based batteries during use is much higher than that of ordinary batteries. Severe gas production in the battery will affect the performance of the battery, and the battery packaging will be affected by excessive gas production, resulting in leakage, insulation withstand voltage failure, and even thermal runaway.

[0003] However, there is currently no method for detecting the gas production of battery cells with high accuracy, which can accurately detect the gas production of battery cells in a battery system. In addition, the battery monitoring system is still unable to identify the risks of battery cell leakage and thermal runaway caused by abnormal gas production in advance.

[0004] Accordingly, a new solution is needed in the art to solve the above problems. Summary of the invention

[0005] In order to overcome the above defects, the present invention is proposed to solve or at least partially solve the above technical problems. The present invention provides a method for detecting gas production of a battery cell, an electronic device and a storage medium.

[0006] In a first aspect, the present invention provides a method for detecting gas production of a battery cell, characterized in that the method comprises:

[0007] Determining the positive electrode capacity loss and the negative electrode capacity loss of the battery cell;

[0008] Obtaining a functional relationship between the gas production of the positive electrode of the battery cell and the capacity loss of the positive electrode, and a functional relationship between the gas production of the negative electrode of the battery cell and the capacity loss of the negative electrode;

[0009] The gas production of the battery cell is determined based on the positive electrode capacity loss, the negative electrode capacity loss, the functional relationship between the positive electrode gas production of the battery cell and the positive electrode capacity loss, and the functional relationship between the negative electrode gas production of the battery cell and the negative electrode capacity loss.

[0010] In one embodiment, the positive electrode capacity loss and the negative electrode capacity loss of the battery cell are determined based on the following steps, including:

[0011] Based on the battery cell, a first button battery, a second button battery and a third button battery are manufactured, wherein the first button battery comprises the positive electrode of the battery cell, the second button battery comprises the negative electrode of the battery cell, and the third button battery comprises the positive electrode and the negative electrode of the battery cell;

[0012] Performing an initial life test on the first button battery, the second button battery, and the third button battery respectively to obtain a first voltage-capacity relationship, a second voltage-capacity relationship, a third voltage-capacity relationship, and a fourth voltage-capacity relationship;

[0013] Obtain the charging interval and ambient temperature triggered by the user;

[0014] When the ambient temperature satisfies a preset condition, acquiring a fifth voltage-capacity relationship and a sixth voltage-capacity relationship based on the charging interval, the third voltage-capacity relationship and the fourth voltage-capacity relationship respectively;

[0015] Determine the positive electrode capacity loss of the battery cell based on the first voltage-capacity relationship, the third voltage-capacity relationship, and the fifth voltage-capacity relationship;

[0016] The negative electrode capacity loss of the battery cell is determined based on the second voltage-capacity relationship, the fourth voltage-capacity relationship, and the sixth voltage-capacity relationship.

[0017] In one embodiment, the obtaining of the first voltage-capacity relationship, the second voltage-capacity relationship, the third voltage-capacity relationship and the fourth voltage-capacity relationship includes:

[0018] Based on the early life tests respectively performed on the first button battery, the second button battery and the third button battery, a first voltage-capacity relationship, a second voltage-capacity relationship and a seventh voltage-capacity relationship are obtained;

[0019] performing fitting operations on the first voltage-capacity relationship and the second voltage-capacity relationship respectively;

[0020] Acquire a first mapping relationship based on the first voltage-capacity relationship and the second voltage-capacity relationship after performing a fitting operation;

[0021] When the first mapping relationship is constrained by the seventh voltage-capacity relationship, the first mapping relationship is solved to obtain the third voltage-capacity relationship and the fourth voltage-capacity relationship.

[0022] In one embodiment, the acquiring a fifth voltage-capacity relationship and a sixth voltage-capacity relationship based on the charging interval, the third voltage-capacity relationship, and the fourth voltage-capacity relationship, respectively, includes:

[0023] acquiring an eighth voltage-capacity relationship corresponding to the charging interval from the third voltage-capacity relationship;

[0024] Acquire a ninth voltage-capacity relationship corresponding to the charging interval from the fourth voltage-capacity relationship;

[0025] performing fitting operations on the eighth voltage-capacity relationship and the ninth voltage-capacity relationship respectively;

[0026] Acquire a second mapping relationship based on the eighth voltage-capacity relationship and the ninth voltage-capacity relationship after performing the fitting operation;

[0027] Obtain the tenth voltage-capacity relationship of the user-side battery cell;

[0028] When the second mapping relationship is constrained by the tenth voltage-capacity relationship, the second mapping relationship is solved to obtain the fifth voltage-capacity relationship and the sixth voltage-capacity relationship.

[0029] In one embodiment, the calculation formula for determining the positive electrode capacity loss of the battery cell based on the first voltage-capacity relationship, the third voltage-capacity relationship, and the fifth voltage-capacity relationship is:

[0030] Q 正loss =(di)Q 1

[0031] Among them, Q 正loss is the positive electrode capacity loss of the battery cell, d is the first-order coefficient of the third voltage-capacity relationship, i is the first-order coefficient of the fifth voltage-capacity relationship, Q 1 is the capacity corresponding to the first voltage-capacity relationship;

[0032] The calculation formula for determining the negative electrode capacity loss of the battery cell based on the second voltage-capacity relationship, the fourth voltage-capacity relationship and the sixth voltage-capacity relationship is:

[0033] Q 负loss =(ek)Q 2

[0034] Among them, Q 负loss is the negative electrode capacity loss of the battery cell, e is the first-order coefficient of the second voltage-capacity relationship, i is the first-order coefficient of the sixth voltage-capacity relationship, Q 2 is the capacity corresponding to the second voltage-capacity relationship.

[0035] In one embodiment, the obtaining of the functional relationship between the gas production of the positive electrode of the battery cell and the positive electrode capacity loss, and the functional relationship between the gas production of the negative electrode of the battery cell and the negative electrode capacity loss, comprises:

[0036] Performing a charge and discharge test experiment on the battery cell, and when the health state reaches a first preset threshold, disassembling the battery cell and collecting gas generated by the battery cell;

[0037] Detecting the gas composition of the gas produced to obtain the molar number of the gas produced by the positive electrode and the molar number of the gas produced by the negative electrode of the battery cell;

[0038] Obtaining a functional relationship between the molar number of gas produced by the positive electrode and the capacity loss of the positive electrode, and a functional relationship between the molar number of gas produced by the negative electrode and the capacity loss of the negative electrode;

[0039] The functional relationship between the positive electrode gas production amount and the positive electrode capacity loss of the battery cell is determined based on the functional relationship between the molar number of gas produced by the positive electrode and the positive electrode capacity loss, and the functional relationship between the negative electrode gas production amount and the negative electrode capacity loss of the battery cell is determined based on the functional relationship between the molar number of gas produced by the negative electrode and the negative electrode capacity loss.

[0040] In one embodiment, the functional relationship between the molar number of gas produced by the positive electrode and the capacity loss of the positive electrode is:

[0041]

[0042] Among them, M 正极产气 is the number of moles of gas produced by the positive electrode, Q 正loss is the positive electrode capacity loss, A 1 , B 1 , C 1 are the polynomial coefficients;

[0043] The functional relationship between the molar number of gas produced by the negative electrode and the capacity loss of the negative electrode is:

[0044]

[0045] Among them, M 负极产气 is the number of moles of gas produced by the negative electrode, Q 负loss is the negative electrode capacity loss, A 2 , B 2 , C 2 are the polynomial coefficients;

[0046] The functional relationship between the gas production of the positive electrode of the battery cell and the capacity loss of the positive electrode is:

[0047] V 正极产气 =M 正极产气 *RT / P=F(Q 正loss )*RT / P

[0048] Among them, V 正极产气 is the gas production of the positive electrode of the battery cell, R is the proportional constant of the ideal state equation, T is the temperature, and P is the pressure;

[0049] The functional relationship between the negative electrode gas generation of the battery cell and the negative electrode capacity loss is:

[0050] V 负极产气 =M 负极产气 *RT / P=F(Q 负loss )*RT / P

[0051] Among them, V 负极产气 It is the gas production of the negative electrode of the battery cell.

[0052] In one embodiment, the determining the gas production of the battery cell based on the positive electrode capacity loss, the negative electrode capacity loss, the functional relationship between the positive electrode gas production of the battery cell and the positive electrode capacity loss, and the functional relationship between the negative electrode gas production of the battery cell and the negative electrode capacity loss includes:

[0053] Calculating the positive electrode gas production of the battery cell based on a functional relationship between the positive electrode capacity loss, the positive electrode gas production of the battery cell and the positive electrode capacity loss;

[0054] Calculating the negative electrode gas production of the battery cell based on the functional relationship between the negative electrode capacity loss, the negative electrode gas production of the battery cell and the negative electrode capacity loss;

[0055] The gas generation amount of the battery cell is determined based on the gas generation amount of the positive electrode of the battery cell and the gas generation amount of the negative electrode of the battery cell.

[0056] In a second aspect, a battery pack fault detection method is provided, the method comprising: obtaining a gas production amount of each battery cell in the battery pack; and determining whether the battery pack has a fault based on the gas production amount of the battery cell.

[0057] In one embodiment, determining whether the battery pack is faulty based on the gas production of the battery cell includes: determining the gas production rate of the battery cell based on the gas production of the battery cell; comparing the gas production rate of the battery cell with a second preset threshold, and determining whether the battery pack is faulty based on the comparison result.

[0058] In one embodiment, determining whether the battery pack has a fault based on the gas production of the battery cells includes: determining an outlier value of each battery cell based on the gas production of each battery cell; comparing the outlier value of each battery cell with a third preset threshold value, and determining whether the battery pack has a fault based on the comparison result.

[0059] In a third aspect, an electronic device is provided, comprising at least one processor and at least one storage device, wherein the storage device is suitable for storing a plurality of program codes, wherein the program codes are suitable for being loaded and run by the processor to execute any of the aforementioned methods for detecting gas production of a battery cell, or to execute any of the aforementioned methods for detecting a battery pack fault.

[0060] In a fourth aspect, a computer-readable storage medium is provided, wherein a plurality of program codes are stored therein, wherein the program codes are suitable for being loaded and run by a processor to execute any of the aforementioned methods for detecting gas production of a battery cell, or to execute any of the aforementioned methods for detecting a battery pack fault.

[0061] Solution 1. A method for detecting gas production of a battery cell, characterized in that the method comprises:

[0062] Determining the positive electrode capacity loss and the negative electrode capacity loss of the battery cell;

[0063] Obtaining a functional relationship between the gas production of the positive electrode of the battery cell and the capacity loss of the positive electrode, and a functional relationship between the gas production of the negative electrode of the battery cell and the capacity loss of the negative electrode;

[0064] The gas production of the battery cell is determined based on the positive electrode capacity loss, the negative electrode capacity loss, the functional relationship between the positive electrode gas production of the battery cell and the positive electrode capacity loss, and the functional relationship between the negative electrode gas production of the battery cell and the negative electrode capacity loss.

[0065] Solution 2. The method for detecting gas production of a battery cell according to Solution 1 is characterized in that the positive electrode capacity loss and the negative electrode capacity loss of the battery cell are determined based on the following steps, including:

[0066] Based on the battery cell, a first button battery, a second button battery and a third button battery are manufactured, wherein the first button battery comprises the positive electrode of the battery cell, the second button battery comprises the negative electrode of the battery cell, and the third button battery comprises the positive electrode and the negative electrode of the battery cell;

[0067] Performing an initial life test on the first button battery, the second button battery, and the third button battery respectively to obtain a first voltage-capacity relationship, a second voltage-capacity relationship, a third voltage-capacity relationship, and a fourth voltage-capacity relationship;

[0068] Obtain the charging interval and ambient temperature triggered by the user;

[0069] When the ambient temperature satisfies a preset condition, acquiring a fifth voltage-capacity relationship and a sixth voltage-capacity relationship based on the charging interval, the third voltage-capacity relationship and the fourth voltage-capacity relationship respectively;

[0070] Determine the positive electrode capacity loss of the battery cell based on the first voltage-capacity relationship, the third voltage-capacity relationship, and the fifth voltage-capacity relationship;

[0071] The negative electrode capacity loss of the battery cell is determined based on the second voltage-capacity relationship, the fourth voltage-capacity relationship, and the sixth voltage-capacity relationship.

[0072] Solution 3. The method for detecting gas production of a battery cell according to Solution 2 is characterized in that obtaining the first voltage-capacity relationship, the second voltage-capacity relationship, the third voltage-capacity relationship and the fourth voltage-capacity relationship comprises:

[0073] Based on the early life tests respectively performed on the first button battery, the second button battery and the third button battery, a first voltage-capacity relationship, a second voltage-capacity relationship and a seventh voltage-capacity relationship are obtained;

[0074] performing fitting operations on the first voltage-capacity relationship and the second voltage-capacity relationship respectively;

[0075] Acquire a first mapping relationship based on the first voltage-capacity relationship and the second voltage-capacity relationship after performing a fitting operation;

[0076] When the first mapping relationship is constrained by the seventh voltage-capacity relationship, the first mapping relationship is solved to obtain the third voltage-capacity relationship and the fourth voltage-capacity relationship.

[0077] Solution 4. The method for detecting the gas production of a battery cell according to Solution 2 is characterized in that the fifth voltage-capacity relationship and the sixth voltage-capacity relationship are respectively obtained based on the charging interval, the third voltage-capacity relationship and the fourth voltage-capacity relationship, including:

[0078] acquiring an eighth voltage-capacity relationship corresponding to the charging interval from the third voltage-capacity relationship;

[0079] Acquire a ninth voltage-capacity relationship corresponding to the charging interval from the fourth voltage-capacity relationship;

[0080] performing fitting operations on the eighth voltage-capacity relationship and the ninth voltage-capacity relationship respectively;

[0081] Acquire a second mapping relationship based on the eighth voltage-capacity relationship and the ninth voltage-capacity relationship after performing the fitting operation;

[0082] Obtain the tenth voltage-capacity relationship of the user-side battery cell;

[0083] When the second mapping relationship is constrained by the tenth voltage-capacity relationship, the second mapping relationship is solved to obtain the fifth voltage-capacity relationship and the sixth voltage-capacity relationship.

[0084] Solution 5. The method for detecting gas production of a battery cell according to Solution 2 is characterized in that:

[0085] The calculation formula for determining the positive electrode capacity loss of the battery cell based on the first voltage-capacity relationship, the third voltage-capacity relationship, and the fifth voltage-capacity relationship is:

[0086] Q 正loss =(di)Q 1

[0087] Among them, Q 正loss is the positive electrode capacity loss of the battery cell, d is the first-order coefficient of the third voltage-capacity relationship, i is the first-order coefficient of the fifth voltage-capacity relationship, Q 1 is the capacity corresponding to the first voltage-capacity relationship;

[0088] The calculation formula for determining the negative electrode capacity loss of the battery cell based on the second voltage-capacity relationship, the fourth voltage-capacity relationship and the sixth voltage-capacity relationship is:

[0089] Q 负loss =(ek)Q 2

[0090] Among them, Q 负loss is the negative electrode capacity loss of the battery cell, e is the first-order coefficient of the second voltage-capacity relationship, i is the first-order coefficient of the sixth voltage-capacity relationship, Q 2 is the capacity corresponding to the second voltage-capacity relationship.

[0091] Solution 6. The method for detecting the gas production of a battery cell according to Solution 1 is characterized in that the step of obtaining the functional relationship between the gas production of the positive electrode of the battery cell and the positive electrode capacity loss, and the functional relationship between the gas production of the negative electrode of the battery cell and the negative electrode capacity loss, comprises:

[0092] Performing a charge and discharge test experiment on the battery cell, and when the health state reaches a first preset threshold, disassembling the battery cell and collecting gas generated by the battery cell;

[0093] Detecting the gas composition of the gas produced to obtain the molar number of the gas produced by the positive electrode and the molar number of the gas produced by the negative electrode of the battery cell;

[0094] Obtaining a functional relationship between the molar number of gas produced by the positive electrode and the capacity loss of the positive electrode, and a functional relationship between the molar number of gas produced by the negative electrode and the capacity loss of the negative electrode;

[0095] The functional relationship between the positive electrode gas production amount and the positive electrode capacity loss of the battery cell is determined based on the functional relationship between the molar number of gas produced by the positive electrode and the positive electrode capacity loss, and the functional relationship between the negative electrode gas production amount and the negative electrode capacity loss of the battery cell is determined based on the functional relationship between the molar number of gas produced by the negative electrode and the negative electrode capacity loss.

[0096] Solution 7. The method for detecting gas production of a battery cell according to Solution 6 is characterized in that the functional relationship between the molar number of gas produced by the positive electrode and the capacity loss of the positive electrode is:

[0097]

[0098] Among them, M 正极产气 is the number of moles of gas produced by the positive electrode, Q 正loss is the positive electrode capacity loss, A 1 , B 1 , C 1 are the polynomial coefficients;

[0099] The functional relationship between the molar number of gas produced by the negative electrode and the capacity loss of the negative electrode is:

[0100]

[0101] Among them, M 负极产气 is the number of moles of gas produced by the negative electrode, Q 负loss is the negative electrode capacity loss, A 2 , B 2 , C 2 are the polynomial coefficients;

[0102] The functional relationship between the gas production of the positive electrode of the battery cell and the capacity loss of the positive electrode is:

[0103] V 正极产气 =M 正极产气 *RT / P=F(Q 正loss )*RT / P

[0104] Among them, V 正极产气 is the gas production of the positive electrode of the battery cell, R is the proportional constant of the ideal state equation, T is the temperature, and P is the pressure;

[0105] The functional relationship between the negative electrode gas generation of the battery cell and the negative electrode capacity loss is:

[0106] V 负极产气 =M 负极产气 *RT / P=F(Q 负loss )*RT / P

[0107] Among them, V 负极产气 It is the gas production of the negative electrode of the battery cell.

[0108] Solution 8. The method for detecting the gas production of a battery cell according to Solution 1 is characterized in that the gas production of the battery cell is determined based on the positive electrode capacity loss, the negative electrode capacity loss, the functional relationship between the positive electrode gas production of the battery cell and the positive electrode capacity loss, and the functional relationship between the negative electrode gas production of the battery cell and the negative electrode capacity loss, including:

[0109] Calculating the positive electrode gas production of the battery cell based on a functional relationship between the positive electrode capacity loss, the positive electrode gas production of the battery cell and the positive electrode capacity loss;

[0110] Calculating the negative electrode gas production of the battery cell based on the functional relationship between the negative electrode capacity loss, the negative electrode gas production of the battery cell and the negative electrode capacity loss;

[0111] The gas generation amount of the battery cell is determined based on the gas generation amount of the positive electrode of the battery cell and the gas generation amount of the negative electrode of the battery cell.

[0112] Solution 9. A battery pack fault detection method, characterized in that the method comprises:

[0113] According to the method for detecting gas production of a battery cell described in any one of schemes 1 to 8, obtaining the gas production of each battery cell in the battery pack;

[0114] Determine whether the battery pack fails based on the gas production of the battery cells.

[0115] Solution 10. The battery pack fault detection method according to Solution 9 is characterized in that determining whether the battery pack has a fault based on the gas production of the battery cell comprises:

[0116] Determining a gas production rate of the battery cell based on the gas production of the battery cell;

[0117] The gas generation rate of the battery cell is compared with a second preset threshold value, and whether the battery pack fails is determined based on the comparison result.

[0118] Solution 11. The battery pack fault detection method according to Solution 9 is characterized in that determining whether the battery pack has a fault based on the gas production of the battery cell comprises:

[0119] Determining an outlier value of each battery cell based on the battery cell gas production of each battery cell;

[0120] The outlier value of each battery cell is compared with a third preset threshold value, and whether the battery pack fails is determined based on the comparison result.

[0121] Scheme 12. An electronic device, comprising at least one processor and at least one storage device, wherein the storage device is suitable for storing multiple program codes, and is characterized in that the program codes are suitable for being loaded and run by the processor to execute the battery cell gas production detection method described in any one of Schemes 1 to 8, or to execute the battery pack fault detection method described in any one of Schemes 9 to 11.

[0122] Scheme 13. A computer-readable storage medium storing a plurality of program codes, characterized in that the program codes are suitable for being loaded and run by a processor to execute the battery cell gas production detection method described in any one of Schemes 1 to 8, or to execute the battery pack fault detection method described in any one of Schemes 9 to 11.

[0123] The above one or more technical solutions of the present invention have at least one or more of the following beneficial effects:

[0124] The method for detecting the gas production of a battery cell in the present invention includes determining the positive electrode capacity loss and the negative electrode capacity loss of the battery cell, obtaining the functional relationship between the positive electrode gas production of the battery cell and the positive electrode capacity loss, and the functional relationship between the negative electrode gas production of the battery cell and the negative electrode capacity loss, and determining the gas production of the battery cell based on the positive electrode capacity loss, the negative electrode capacity loss, the functional relationship between the positive electrode gas production of the battery cell and the positive electrode capacity loss, and the functional relationship between the negative electrode gas production of the battery cell and the negative electrode capacity loss. In this way, the gas production of the battery cell with high accuracy is obtained, and the detection accuracy of the gas production of the battery cell is improved, so that leakage and thermal runaway caused by gas production of the battery cell can be effectively avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0125] The disclosure of the present invention will become more easily understood with reference to the accompanying drawings. It is easy for those skilled in the art to understand that these drawings are only for illustrative purposes and are not intended to limit the scope of protection of the present invention. In addition, similar numbers in the figures are used to represent similar components, among which:

[0126] Figure 1 1 is a schematic flow chart of the main steps of a method for detecting gas production of a battery cell according to an embodiment of the present invention;

[0127] Figure 2 is a schematic diagram of a process for determining a positive electrode capacity loss and a negative electrode capacity loss of a battery cell in an embodiment;

[0128] Figure 3 The present invention is a flow chart of obtaining the functional relationship between the gas production of the positive electrode of the battery cell and the positive electrode capacity loss, and the functional relationship between the gas production of the negative electrode of the battery cell and the negative electrode capacity loss in one embodiment;

[0129] Figure 4 is a schematic diagram of a process for determining the gas production of a battery cell in an embodiment;

[0130] Figure 5 is a schematic flow chart of a battery pack fault detection method in an embodiment;

[0131] Figure 6 The figure is a flow chart of an electronic device in one embodiment. DETAILED DESCRIPTION

[0132] Some embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention.

[0133] In the description of the present invention, "module" and "processor" may include hardware, software or a combination of the two. A module may include hardware circuits, various suitable sensors, communication ports, and memories, and may also include software parts, such as program codes, or a combination of software and hardware. The processor may be a central processing unit, a microprocessor, an image processor, a digital signal processor, or any other suitable processor. The processor has data and / or signal processing functions. The processor may be implemented in software, hardware, or a combination of the two. Non-temporary computer-readable storage media include any suitable medium that can store program codes, such as a magnetic disk, a hard disk, an optical disk, a flash memory, a read-only memory, a random access memory, and the like. The term "A and / or B" means all possible combinations of A and B, such as only A, only B, or A and B. The term "at least one A or B" or "at least one of A and B" has a similar meaning to "A and / or B", and may include only A, only B, or A and B. The singular terms "one" and "the" may also include plural forms.

[0134] Currently, there is still no method for detecting the gas production of battery cells with high accuracy, which can accurately detect the gas production of battery cells in a battery system.

[0135] To this end, the present application proposes a method for detecting the gas production of a battery cell, an electronic device, and a storage medium, including determining the positive electrode capacity loss and negative electrode capacity loss of the battery cell, obtaining the functional relationship between the positive electrode gas production of the battery cell and the positive electrode capacity loss, and the functional relationship between the negative electrode gas production of the battery cell and the negative electrode capacity loss, and determining the gas production of the battery cell based on the positive electrode capacity loss, the negative electrode capacity loss, the functional relationship between the positive electrode gas production of the battery cell and the positive electrode capacity loss, and the functional relationship between the negative electrode gas production of the battery cell and the negative electrode capacity loss. In this way, the gas production of the battery cell with high accuracy is obtained, and the detection accuracy of the gas production of the battery cell is improved, so that leakage and thermal runaway caused by gas production of the battery cell can be effectively prevented.

[0136] See attached Figure 1 , Figure 1It is a flow chart of main steps of a method for detecting gas production of a battery cell according to an embodiment of the present invention.

[0137] like Figure 1 As shown, the method for detecting gas generation of a battery cell in the embodiment of the present invention mainly includes the following steps S100 to S300.

[0138] Step S100: determining the positive electrode capacity loss and the negative electrode capacity loss of the battery cell.

[0139] Step S200: obtaining a functional relationship between the gas production of the positive electrode of the battery cell and the capacity loss of the positive electrode, and a functional relationship between the gas production of the negative electrode of the battery cell and the capacity loss of the negative electrode.

[0140] Step S300: Determine the gas production of the battery cell based on the positive electrode capacity loss, the negative electrode capacity loss, the functional relationship between the positive electrode gas production of the battery cell and the positive electrode capacity loss, and the functional relationship between the negative electrode gas production of the battery cell and the negative electrode capacity loss.

[0141] Based on the above steps S100 to S300, the positive electrode capacity loss and negative electrode capacity loss of the battery cell are first determined, and the functional relationship between the positive electrode gas production and the positive electrode capacity loss, and the functional relationship between the negative electrode gas production and the negative electrode capacity loss of the battery cell are obtained. The gas production of the battery cell is determined based on the positive electrode capacity loss, the negative electrode capacity loss, the functional relationship between the positive electrode gas production and the positive electrode capacity loss, and the functional relationship between the negative electrode gas production and the negative electrode capacity loss of the battery cell. In this way, the gas production of the battery cell with high accuracy is obtained, and the detection accuracy of the gas production of the battery cell is improved, so that leakage and thermal runaway caused by gas production of the battery cell can be effectively prevented.

[0142] The above steps S100 to S300 are further explained below.

[0143] Specific as Figure 2 As shown, the above step S100 can be implemented through the following steps S101 to S106.

[0144] Step S101: manufacturing a first button battery, a second button battery and a third button battery based on the battery cell, wherein the first button battery includes the positive electrode of the battery cell, the second button battery includes the negative electrode of the battery cell, and the third button battery includes the positive electrode and the negative electrode of the battery cell.

[0145] Specifically, for the battery cell, a first button battery of a positive electrode, a separator, and a lithium sheet (positive electrode / Li), a second button battery of a negative electrode, a separator, and a lithium sheet (negative electrode / Li), and a third button battery of a positive electrode, a separator, and a negative electrode (positive electrode / negative electrode) are respectively manufactured.

[0146] Step S102: performing an initial life test on the first button battery, the second button battery and the third button battery respectively to obtain a first voltage-capacity relationship, a second voltage-capacity relationship, a third voltage-capacity relationship and a fourth voltage-capacity relationship.

[0147] In one embodiment, a voltage-capacity curve can be used as an example of a voltage-capacity relationship, but is not limited thereto, wherein the voltage refers to the terminal voltage of the battery.

[0148] In order to make the purpose, technical solution and advantages of the present invention more clear, the following is a detailed description of the battery cell gas production detection method of the present application in combination with the accompanying drawings and embodiments, taking the voltage-capacity curve as an example of the voltage-capacity relationship. It should be understood by those skilled in the art that the specific embodiments described herein are only used to explain the present invention, and are not intended to limit the battery cell gas production detection method described in the present invention to use the voltage-capacity curve as the voltage-capacity relationship.

[0149] The initial life test mainly performs BOL test on the first button battery, the second button battery and the third button battery. The BOL (Beginning of Life) test is a comprehensive physical examination of the battery at the beginning of its life.

[0150] In a specific embodiment, the obtaining of the first voltage-capacity relationship, the second voltage-capacity relationship, the third voltage-capacity relationship and the fourth voltage-capacity relationship includes: obtaining the first voltage-capacity relationship, the second voltage-capacity relationship and the seventh voltage-capacity relationship (f1) based on the initial life tests performed on the first button battery, the second button battery and the third button battery respectively; performing fitting operations on the first voltage-capacity relationship and the second voltage-capacity relationship respectively; obtaining a first mapping relationship based on the first voltage-capacity relationship and the second voltage-capacity relationship after the fitting operation; solving the first mapping relationship while constraining the first mapping relationship by using the seventh voltage-capacity relationship to obtain the third voltage-capacity relationship and the fourth voltage-capacity relationship.

[0151] Specifically, this step mainly tests the battery cell under standard charging conditions. Based on the test, the voltage-capacity curve of each button battery can be drawn, where the voltage-capacity curve is a Voltage-SOC curve. In this embodiment, the first voltage-capacity curve corresponding to the first button battery is c1, the second voltage-capacity curve corresponding to the second button battery is a1, and the seventh voltage-capacity curve corresponding to the third button battery is f1.

[0152] The third voltage-capacity curve c2 is a curve obtained by scaling and translating the first voltage-capacity curve c1.

[0153] The fourth voltage-capacity curve a2 is a curve obtained by scaling and translating the second voltage-capacity curve a1.

[0154] Specifically, by using the data analysis method, the first voltage-capacity curve c1 and the second voltage-capacity curve a1 are scaled and translated respectively to obtain:

[0155] c2=d*c1+b

[0156] a2=e*a1+h

[0157] Where d, b, e, and h are all polynomial coefficients;

[0158] Continue to reconstruct the curve to obtain the first mapping relationship (which can be the first mapping curve), the formula is as follows:

[0159] s1=c2-a2

[0160] The first mapping relationship s1 is simulated and solved by the least square method, and the error accuracy between the fitted curves s1 and f1 is ensured to be ≤2% during the solution process, so as to obtain the polynomial coefficients d, b, e, and h. After solving the coefficients, the third voltage-capacity curve c2 and the fourth voltage-capacity curve a2 are obtained.

[0161] Step S103: Acquire the charging interval and ambient temperature triggered by the user.

[0162] Specifically, for the charging test at the user end, the charging range and current ambient temperature of the battery at the user end are obtained while ensuring that the charging exceeds 10% SOC.

[0163] Step S104: when the ambient temperature meets a preset condition, obtaining a fifth voltage-capacity relationship and a sixth voltage-capacity relationship based on the charging interval, the third voltage-capacity relationship and the fourth voltage-capacity relationship, respectively.

[0164] Specifically, when the charging interval is [SOC1, SOC2] and the difference between the temperature and the test temperature of the button battery during the BOL period is less than the preset temperature threshold, the simulation condition of the user end is triggered. Under this simulation condition, the scaling, translation and reconstruction operations of the curve are triggered to obtain the fifth voltage-capacity curve c4 and the sixth voltage-capacity curve a4.

[0165] In a specific embodiment, the fifth voltage-capacity relationship and the sixth voltage-capacity relationship are obtained based on the charging interval, the third voltage-capacity relationship and the fourth voltage-capacity relationship, respectively, including: obtaining an eighth voltage-capacity relationship c3 corresponding to the charging interval from the third voltage-capacity relationship c2; obtaining a ninth voltage-capacity relationship a3 corresponding to the charging interval from the fourth voltage-capacity relationship a2; performing fitting operations on the eighth voltage-capacity relationship c3 and the ninth voltage-capacity relationship a3, respectively; obtaining a second mapping relationship s2 based on the eighth voltage-capacity relationship and the ninth voltage-capacity relationship after the fitting operation; obtaining the tenth voltage-capacity relationship f2 of the user-end battery cell; and solving the second mapping relationship by using the tenth voltage-capacity relationship f2 to constrain the second mapping relationship s2 to obtain the fifth voltage-capacity relationship and the sixth voltage-capacity relationship.

[0166] Specifically, the curve corresponding to the interval [SOC1, SOC2] is intercepted from the third voltage-capacity curve c2 to obtain the eighth voltage-capacity curve c3. The curve corresponding to the interval [SOC1, SOC2] is intercepted from the fourth voltage-capacity curve a2 to obtain the ninth voltage-capacity curve a3.

[0167] After scaling and translating the eighth voltage-capacity curve c3 and the ninth voltage-capacity curve a3, the following is obtained:

[0168] c4=i*c3+j

[0169] a4=k*a3+l

[0170] Among them, i, j, k, and l are all polynomial coefficients;

[0171] After the charging test is performed at the user end, the voltage-capacity curve of the battery cell, that is, the tenth voltage-capacity curve f2, can be obtained.

[0172] Continue to reconstruct the curve to obtain the second mapping relationship (second mapping curve) s2, the formula is as follows:

[0173] s2=c4-a4

[0174] The above formula is simulated and solved by the least square method, and the error accuracy between the fitted curves s2 and f2 is ensured to be ≤2% during the solution process, so as to obtain the polynomial coefficients i, j, k, and l. The fifth voltage-capacity curve c4 and the sixth voltage-capacity curve a4 are further obtained.

[0175] Step S105: determining the positive electrode capacity loss of the battery cell based on the first voltage-capacity relationship, the third voltage-capacity relationship and the fifth voltage-capacity relationship.

[0176] Specifically, the positive electrode capacity loss of the battery cell is further calculated according to the capacity of the curve c1 , the third voltage-capacity relationship c2 , and the fifth voltage-capacity relationship c4 .

[0177] In a specific embodiment, the calculation formula for determining the positive electrode capacity loss of the battery cell based on the first voltage-capacity relationship, the third voltage-capacity relationship and the fifth voltage-capacity relationship is:

[0178] Q 正loss =(di)Q 1

[0179] Among them, Q 正loss is the positive electrode capacity loss of the battery cell, d is the first-order coefficient of the third voltage-capacity relationship, i is the first-order coefficient of the fifth voltage-capacity relationship, Q 1 is the capacity corresponding to the first voltage-capacity relationship.

[0180] Specifically, the capacity of the first voltage-capacity relationship c1 is Q1, and the capacity of the second voltage-capacity relationship a1 is Q2. Therefore, the positive electrode capacity loss of the battery cell is determined based on the above calculation formula of the positive electrode capacity loss.

[0181] Step S106: determining the negative electrode capacity loss of the battery cell based on the second voltage-capacity relationship, the fourth voltage-capacity relationship and the sixth voltage-capacity relationship.

[0182] In a specific embodiment, the calculation formula for determining the negative electrode capacity loss of the battery cell based on the second voltage-capacity relationship, the fourth voltage-capacity relationship and the sixth voltage-capacity relationship is:

[0183] Q 负loss =(ek)Q 2

[0184] Among them, Q 负loss is the negative electrode capacity loss of the battery cell, e is the first-order coefficient of the second voltage-capacity relationship, i is the first-order coefficient of the sixth voltage-capacity relationship, Q 2 is the capacity corresponding to the second voltage-capacity relationship.

[0185] By adopting the method of curve reconstruction and data fitting, the causes of cell capacity decay are decomposed according to the charge and discharge characteristics of the cell under fixed working conditions, thereby determining the positive electrode capacity loss and negative electrode capacity loss of the cell, which is conducive to accurately predicting the gas production of the cell.

[0186] The above is a further description of step S100 , and the following is a further description of step S200 .

[0187] Specific as Figure 3 As shown, step S200 can be specifically implemented through the following steps S201 to S204.

[0188] Step S201: performing a charge and discharge test experiment on the battery cell, and when the health status reaches a preset threshold, disassembling the battery cell and collecting the gas generated by the battery cell.

[0189] Specifically, the battery cells are subjected to operating and storage charge and discharge tests, where the operating conditions in the test include fast charging conditions, discharge conditions required by the WLTC national standard, and static conditions. After the charge and discharge tests, the battery cells whose battery health status (SOH) reaches the preset threshold are disassembled and the gas produced is collected.

[0190] For example, 96%, 92%, 88%, 84%, 80% and the like can be used as examples of the preset thresholds, but are not limited thereto. Based on this, disassembly and collection of gas produced can be performed when the health status reaches 96%, 92%, 88%, 84% and 80% respectively.

[0191] Step S202: Detect the gas composition of the gas generated, and obtain the molar number of the gas generated by the positive electrode and the molar number of the gas generated by the negative electrode of the battery cell.

[0192] For example, the gas components of the gas production can be decomposed by gas chromatography-mass spectrometry. According to the reaction mechanism, oxidizing gases such as CO2 and CO are caused by the positive electrode gas production, and the molar number is recorded as M1. Reducing gases such as C2H4, CH4, etc. are reducing gases, and the molar number is recorded as M2.

[0193] Step S203: obtaining a functional relationship between the molar number of gas produced by the positive electrode and the capacity loss of the positive electrode, and a functional relationship between the molar number of gas produced by the negative electrode and the capacity loss of the negative electrode.

[0194] In a specific embodiment, the functional relationship between the molar number of gas produced by the positive electrode and the capacity loss of the positive electrode is:

[0195]

[0196] Among them, M 正极产气 is the number of moles of gas produced by the positive electrode, Q 正loss is the positive electrode capacity loss, A 1 , B 1 , C 1 are polynomial coefficients, F(Q 正loss ) is Q 正loss Functional relationship of

[0197] The functional relationship between the molar number of gas produced by the negative electrode and the capacity loss of the negative electrode is:

[0198]

[0199] Among them, M 负极产气 is the number of moles of gas produced by the negative electrode, Q 负loss is the negative electrode capacity loss, A 2 , B 2 , C 2 are polynomial coefficients, F(Q 负loss ) is Q 负loss The functional relationship of .

[0200] Specifically, the least squares method can be used to solve A 1 , B 1 , C 1 , A 2 , B 2 , C 2 The polynomial coefficients are obtained to obtain the relationship between the molar number of gas produced by the positive electrode and the capacity loss of the positive electrode, and the relationship between the molar number of gas produced by the negative electrode and the capacity loss of the negative electrode.

[0201] Step S204: Determine the functional relationship between the positive electrode gas production amount and the positive electrode capacity loss of the battery cell based on the functional relationship between the molar number of gas produced by the positive electrode and the positive electrode capacity loss, and determine the functional relationship between the negative electrode gas production amount and the negative electrode capacity loss of the battery cell based on the functional relationship between the molar number of gas produced by the negative electrode and the negative electrode capacity loss.

[0202] In a specific embodiment, the functional relationship between the gas generation of the positive electrode of the battery cell and the capacity loss of the positive electrode is:

[0203] V 正极产气 =M 正极产气 RT / P=F(Q 正loss )RT / P

[0204] Among them, V 正极产气 is the gas production of the positive electrode of the battery cell, R is the proportional constant of the ideal state equation, R = 8.31 J / (mol*K), T is the temperature, and P is the pressure;

[0205] The functional relationship between the negative electrode gas generation of the battery cell and the negative electrode capacity loss is:

[0206] V 负极产气 =M 负极产气 RT / P=F(Q 负loss )RT / P

[0207] Among them, V 负极产气It is the gas production of the negative electrode of the battery cell.

[0208] In this way, by disassembling the battery cell and collecting gas, and detecting the gas composition of the battery cell, the gas mole number of the positive electrode gas and the gas mole number of the negative electrode gas can be obtained. Further, based on the relationship between the positive electrode gas production and the gas mole number of the positive electrode gas production, temperature, and pressure, a functional relationship between the positive electrode gas production of the battery cell and the positive electrode capacity loss is established, and a functional relationship between the negative electrode gas production of the battery cell and the negative electrode capacity loss is established. In this way, it is conducive to obtaining the gas production of the battery cell with higher accuracy.

[0209] The above is a further description of step S200 , and the following is a further description of step S300 .

[0210] Specific as Figure 4 As shown, step S300 can be specifically implemented through the following steps S301 to S303.

[0211] Step S301: calculating the positive electrode gas production of the battery cell based on the functional relationship between the positive electrode capacity loss, the positive electrode gas production of the battery cell and the positive electrode capacity loss.

[0212] Specifically, by bringing the positive electrode capacity loss into the functional relationship between the positive electrode gas production of the battery cell and the positive electrode capacity loss, the positive electrode gas production of the battery cell can be obtained.

[0213] Step S302: calculating the negative electrode gas generation of the battery cell based on the functional relationship between the negative electrode capacity loss, the negative electrode gas generation of the battery cell and the negative electrode capacity loss.

[0214] Specifically, by bringing the negative electrode capacity loss into the functional relationship between the negative electrode gas production of the battery cell and the negative electrode capacity loss, the negative electrode gas production of the battery cell can be obtained.

[0215] Step S303: determining the gas production of the battery cell based on the gas production of the positive electrode and the gas production of the negative electrode of the battery cell.

[0216] Specifically, the gas production of the battery cell V = V can be obtained by summing the gas production of the positive electrode and the negative electrode. 正极产气 +V 负极产气 .

[0217] By adopting curve reconstruction and data fitting methods, the different causes of battery cell attenuation are decomposed according to the charging and discharging characteristics of fixed working conditions, and then a functional relationship is established between the loss amount of different dimensions of the battery cell and the gas production. Finally, the gas production of the battery cell can be calculated in real time, and the gas production of the battery cell with high accuracy is obtained, thereby preventing leakage and thermal runaway of the battery cell caused by gas production.

[0218] At present, the battery monitoring system is still unable to identify in advance the risk of battery cell leakage and thermal runaway caused by abnormal gas production. To this end, the present invention also provides a battery pack fault detection method.

[0219] Specific as Figure 5 As shown, the battery pack fault detection method can be implemented through the following steps S501-S502.

[0220] Step S501: According to the aforementioned method for detecting the gas production of a battery cell, the gas production of each battery cell in the battery pack is obtained.

[0221] The gas production of each battery cell in the battery pack can be specifically obtained through steps S100 to S300 described in the aforementioned embodiment, which will not be described in detail here.

[0222] Step S502: Determine whether the battery pack fails based on the gas production of the battery cells.

[0223] In a specific embodiment, determining whether the battery pack has a fault based on the gas production of the battery cell includes: determining the gas production rate of the battery cell based on the gas production of the battery cell; comparing the gas production rate of the battery cell with a second preset threshold value, and determining whether the battery pack has a fault based on the comparison result.

[0224] Specifically, in one embodiment, the gas production rate of the battery cell is first determined by the ratio of the gas production of the battery cell to time, and the gas production rate of the battery cell is further compared with a second preset threshold value. If the gas production rate of the battery cell is greater than the second preset threshold value, it is determined that the battery pack is faulty.

[0225] In a specific embodiment, determining whether the battery pack has a fault based on the gas production of the battery cells includes: determining an outlier value of each battery cell based on the gas production of each battery cell; comparing the outlier value of each battery cell with a third preset threshold value, and determining whether the battery pack has a fault based on the comparison result.

[0226] Specifically, in another embodiment, the outlier value of each battery cell is first determined based on the gas production of each battery cell, and the outlier value of the battery cell is further compared with a third preset threshold value. If the outlier value of the battery cell is greater than the third preset threshold value, it is determined that the battery pack is faulty.

[0227] The outlier detection methods include Rhineda criterion, outlier judgment based on close neighbors, etc. In one case, the standard deviation can also reflect the degree of dispersion of a data set.

[0228] By obtaining the gas production of the battery cells in the battery pack and determining whether the battery pack is faulty, discrete cells with abnormal gas production can be quickly found, effectively avoiding risks such as insulation failure and thermal runaway of the battery pack.

[0229] It should be pointed out that although the various steps in the above embodiments are described in a specific order, those skilled in the art can understand that in order to achieve the effects of the present invention, different steps do not have to be performed in such an order. They can be performed simultaneously (in parallel) or in other orders. These changes are within the scope of protection of the present invention.

[0230] It is understood by those skilled in the art that the present invention implements all or part of the processes in the method of the above embodiment, and can also be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned various method embodiments when executed by the processor. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable storage medium may include: any entity or device, medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory, random access memory, electric carrier signal, telecommunication signal and software distribution medium that can carry the computer program code. It should be noted that the content contained in the computer-readable storage medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable storage media do not include electric carrier signals and telecommunication signals.

[0231] Furthermore, the present invention also provides an electronic device. In an electronic device embodiment according to the present invention, Figure 6 As shown, the electronic device includes at least one processor 61 and at least one storage device 62. The storage device 62 can be configured to store a program for executing the method for detecting the gas production of a battery cell in the above method embodiment. The processor 61 can be configured to execute the program in the storage device 62, which includes but is not limited to executing the program for detecting the gas production of a battery cell in the above method embodiment, or executing the above-mentioned battery pack fault detection method. For ease of explanation, only the part related to the embodiment of the present invention is shown. For specific technical details not disclosed, please refer to the method part of the embodiment of the present invention.

[0232] In an embodiment of the present invention, the electronic device may be a control device device formed by various devices. In some possible implementations, the electronic device may include multiple storage devices and multiple processors. The program for executing the battery cell gas production detection method or battery pack fault detection method of the above method embodiment can be divided into multiple subprograms, and each subprogram can be loaded and run by the processor to execute different steps of the battery cell gas production detection method or battery pack fault detection method of the above method embodiment. Specifically, each subprogram can be stored in different storage devices, and each processor can be configured to execute the programs in one or more storage devices to jointly implement the battery cell gas production detection method or battery pack fault detection method of the above method embodiment, that is, each processor executes different steps of the battery cell gas production detection method or battery pack fault detection method of the above method embodiment, to jointly implement the battery cell gas production detection method or battery pack fault detection method of the above method embodiment.

[0233] The above-mentioned multiple processors may be processors deployed on the same device. For example, the above-mentioned electronic device may be a high-performance device composed of multiple processors, and the above-mentioned multiple processors may be processors configured on the high-performance device. In addition, the above-mentioned multiple processors may also be processors deployed on different devices. For example, the above-mentioned electronic device may be a server cluster, and the above-mentioned multiple processors may be processors on different servers in the server cluster.

[0234] Furthermore, the present invention also provides a computer-readable storage medium. In a computer-readable storage medium embodiment according to the present invention, the computer-readable storage medium can be configured to store a program for executing the battery cell gas production detection method of the above-mentioned method embodiment or executing the aforementioned battery pack fault detection method, and the program can be loaded and run by the processor to implement the above-mentioned battery cell gas production detection method or battery pack fault detection method. For ease of explanation, only the parts related to the embodiment of the present invention are shown. For specific technical details not disclosed, please refer to the method part of the embodiment of the present invention. The computer-readable storage medium may be a storage device formed by various electronic devices. Optionally, the computer-readable storage medium in the embodiment of the present invention is a non-temporary computer-readable storage medium.

[0235] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. A method for detecting gas production of a battery cell, characterized in that: The method comprises: Determining the positive electrode capacity loss and the negative electrode capacity loss of the battery cell; Obtaining a functional relationship between the gas production of the positive electrode of the battery cell and the capacity loss of the positive electrode, and a functional relationship between the gas production of the negative electrode of the battery cell and the capacity loss of the negative electrode; The gas production of the battery cell is determined based on the positive electrode capacity loss, the negative electrode capacity loss, the functional relationship between the positive electrode gas production of the battery cell and the positive electrode capacity loss, and the functional relationship between the negative electrode gas production of the battery cell and the negative electrode capacity loss.

2. The method for detecting gas production of a battery cell according to claim 1, characterized in that: The positive electrode capacity loss and the negative electrode capacity loss of the battery cell are determined based on the following steps, including: Based on the battery cell, a first button battery, a second button battery and a third button battery are manufactured, wherein the first button battery comprises the positive electrode of the battery cell, the second button battery comprises the negative electrode of the battery cell, and the third button battery comprises the positive electrode and the negative electrode of the battery cell; Performing an initial life test on the first button battery, the second button battery, and the third button battery respectively to obtain a first voltage-capacity relationship, a second voltage-capacity relationship, a third voltage-capacity relationship, and a fourth voltage-capacity relationship; Obtain the charging interval and ambient temperature triggered by the user; When the ambient temperature satisfies a preset condition, acquiring a fifth voltage-capacity relationship and a sixth voltage-capacity relationship based on the charging interval, the third voltage-capacity relationship and the fourth voltage-capacity relationship respectively; Determine the positive electrode capacity loss of the battery cell based on the first voltage-capacity relationship, the third voltage-capacity relationship, and the fifth voltage-capacity relationship; The negative electrode capacity loss of the battery cell is determined based on the second voltage-capacity relationship, the fourth voltage-capacity relationship, and the sixth voltage-capacity relationship.

3. The method for detecting gas production of a battery cell according to claim 2, characterized in that: The obtaining of the first voltage-capacity relationship, the second voltage-capacity relationship, the third voltage-capacity relationship and the fourth voltage-capacity relationship comprises: Based on the early life tests respectively performed on the first button battery, the second button battery and the third button battery, a first voltage-capacity relationship, a second voltage-capacity relationship and a seventh voltage-capacity relationship are obtained; performing fitting operations on the first voltage-capacity relationship and the second voltage-capacity relationship respectively; Acquire a first mapping relationship based on the first voltage-capacity relationship and the second voltage-capacity relationship after performing a fitting operation; When the first mapping relationship is constrained by the seventh voltage-capacity relationship, the first mapping relationship is solved to obtain the third voltage-capacity relationship and the fourth voltage-capacity relationship.

4. The method for detecting gas production of a battery cell according to claim 2, characterized in that: The acquiring a fifth voltage-capacity relationship and a sixth voltage-capacity relationship based on the charging interval, the third voltage-capacity relationship and the fourth voltage-capacity relationship respectively includes: acquiring an eighth voltage-capacity relationship corresponding to the charging interval from the third voltage-capacity relationship; Acquire a ninth voltage-capacity relationship corresponding to the charging interval from the fourth voltage-capacity relationship; performing fitting operations on the eighth voltage-capacity relationship and the ninth voltage-capacity relationship respectively; Acquire a second mapping relationship based on the eighth voltage-capacity relationship and the ninth voltage-capacity relationship after performing the fitting operation; Obtain the tenth voltage-capacity relationship of the user-side battery cell; When the second mapping relationship is constrained by the tenth voltage-capacity relationship, the second mapping relationship is solved to obtain the fifth voltage-capacity relationship and the sixth voltage-capacity relationship.

5. The method for detecting gas production of a battery cell according to claim 2, characterized in that: The calculation formula for determining the positive electrode capacity loss of the battery cell based on the first voltage-capacity relationship, the third voltage-capacity relationship, and the fifth voltage-capacity relationship is: Q 正loss =(d-i)Q1 Among them, Q 正loss is the positive electrode capacity loss of the battery cell, d is the first-order coefficient of the third voltage-capacity relationship, i is the first-order coefficient of the fifth voltage-capacity relationship, and Q1 is the capacity corresponding to the first voltage-capacity relationship; The calculation formula for determining the negative electrode capacity loss of the battery cell based on the second voltage-capacity relationship, the fourth voltage-capacity relationship and the sixth voltage-capacity relationship is: Q 负loss =(ek)Q2 Among them, Q 负loss is the negative electrode capacity loss of the battery cell, e is the first-order coefficient of the second voltage-capacity relationship, i is the first-order coefficient of the sixth voltage-capacity relationship, and Q2 is the capacity corresponding to the second voltage-capacity relationship.

6. The method for detecting gas production of a battery cell according to claim 1, characterized in that: The obtaining of the functional relationship between the gas production of the positive electrode of the battery cell and the positive electrode capacity loss, and the functional relationship between the gas production of the negative electrode of the battery cell and the negative electrode capacity loss, comprises: Performing a charge and discharge test experiment on the battery cell, and when the health state reaches a first preset threshold, disassembling the battery cell and collecting gas generated by the battery cell; Detecting the gas composition of the gas produced to obtain the molar number of the gas produced by the positive electrode and the molar number of the gas produced by the negative electrode of the battery cell; Obtaining a functional relationship between the molar number of gas produced by the positive electrode and the capacity loss of the positive electrode, and a functional relationship between the molar number of gas produced by the negative electrode and the capacity loss of the negative electrode; The functional relationship between the positive electrode gas production amount and the positive electrode capacity loss of the battery cell is determined based on the functional relationship between the molar number of gas produced by the positive electrode and the positive electrode capacity loss, and the functional relationship between the negative electrode gas production amount and the negative electrode capacity loss of the battery cell is determined based on the functional relationship between the molar number of gas produced by the negative electrode and the negative electrode capacity loss.

7. The method for detecting gas production of a battery cell according to claim 6, characterized in that: The functional relationship between the molar number of gas produced by the positive electrode and the capacity loss of the positive electrode is: Among them, M 正极产气 is the number of moles of gas produced by the positive electrode, Q 正loss is the positive electrode capacity loss, A1, B1, C1 are polynomial coefficients; The functional relationship between the molar number of gas produced by the negative electrode and the capacity loss of the negative electrode is: Among them, M 负极产气 is the number of moles of gas produced by the negative electrode, Q 负loss is the negative electrode capacity loss, A2, B2, C2 are polynomial coefficients; The functional relationship between the gas production of the positive electrode of the battery cell and the capacity loss of the positive electrode is: V 正极产气 =M 正极产气 *RT / P=F(Q 正loss )*RT / P Among them, V 正极产气 is the gas production of the positive electrode of the battery cell, R is the proportional constant of the ideal state equation, T is the temperature, and P is the pressure; The functional relationship between the negative electrode gas generation of the battery cell and the negative electrode capacity loss is: V 负极产气 =M 负极产气 *RT / P=F(Q 负loss )*RT / P Among them, V 负极产气 It is the gas production of the negative electrode of the battery cell.

8. The method for detecting gas production of a battery cell according to claim 1, characterized in that: The determining the gas production of the battery cell based on the positive electrode capacity loss, the negative electrode capacity loss, the functional relationship between the positive electrode gas production of the battery cell and the positive electrode capacity loss, and the functional relationship between the negative electrode gas production of the battery cell and the negative electrode capacity loss includes: Calculating the positive electrode gas production of the battery cell based on a functional relationship between the positive electrode capacity loss, the positive electrode gas production of the battery cell and the positive electrode capacity loss; Calculating the negative electrode gas production of the battery cell based on the functional relationship between the negative electrode capacity loss, the negative electrode gas production of the battery cell and the negative electrode capacity loss; The gas generation amount of the battery cell is determined based on the gas generation amount of the positive electrode of the battery cell and the gas generation amount of the negative electrode of the battery cell.

9. A battery pack fault detection method, characterized in that: The method comprises: According to the method for detecting gas production of a battery cell according to any one of claims 1 to 8, obtaining the gas production of each battery cell in the battery pack; Determine whether the battery pack fails based on the gas production of the battery cells.

10. The battery pack fault detection method according to claim 9, characterized in that: The determining whether the battery pack fails based on the gas production of the battery cell includes: Determining a gas production rate of the battery cell based on the gas production of the battery cell; The gas generation rate of the battery cell is compared with a second preset threshold value, and whether the battery pack fails is determined based on the comparison result.

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