Method for establishing model for correcting production line capacity grading capacity of second battery cell
By establishing the fitting relationship between battery cells at different temperatures, the capacity classification model of battery cells on the production line was corrected. By combining static and dynamic capacity screening, the problem of capacity change caused by temperature fluctuations during the battery cell capacity classification process was solved, and the accuracy and consistency of battery cell screening were improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANGHAI XUANYI NEW ENERGY DEV CO LTD
- Filing Date
- 2025-12-31
- Publication Date
- 2026-04-14
AI Technical Summary
Existing battery manufacturers experience cell capacity variations during the cell grading process due to ambient temperature fluctuations, leading to screening failures and an inability to obtain accurate cell capacity.
By establishing a modified production line capacity classification model for the second battery cell, the fitting relationship of the battery cell at different temperatures is determined, eliminating the influence of temperature fluctuations on the battery cell capacity. The fitting relationship is used to correct the production line capacity classification of the second battery cell. Combined with the first static capacity screening and the second dynamic capacity screening, the reliability and consistency of battery cell screening are improved.
This enables more accurate cell capacity acquisition under different temperature conditions, improves the reliability and consistency of cell screening, and avoids misjudgments caused by ambient temperature.
Smart Images
Figure CN121859567A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of battery cells, and more particularly to a method for modifying a production line capacity model for a second battery cell and a battery cell screening method. Background Technology
[0002] Batteries are widely used in energy storage and various power markets, and are generally assembled from individual cells into modules or battery pack systems. Currently, most battery manufacturers screen batteries according to fixed specifications based on their capacity before production. This method is simple to apply, but fluctuations in ambient temperature during the actual capacity screening process can cause changes in cell capacity, leading to screening failures. Summary of the Invention
[0003] Some embodiments of this application provide methods for modifying the production line capacity model of the second battery cell and battery cell screening methods. The following describes this application from multiple aspects, and the embodiments and beneficial effects of the following aspects can be referenced each other.
[0004] In a first aspect, embodiments of this application provide a method for establishing a model for correcting the production line capacity rating of a second battery cell, comprising:
[0005] The production line capacity of several first cells that have not been fixed after formation in the same batch is determined and they are grouped together, wherein the second cell is different from the first cell;
[0006] Each cell group is subjected to capacity setting at different preset temperatures to determine the average temperature and corresponding capacity setting of each first cell in each cell group during the capacity setting process at the corresponding preset temperature.
[0007] Based on the production line capacity of each first cell in each cell group and the average temperature and fixed capacity at the corresponding preset temperature, the fitting relationship between the fixed capacity and the average temperature of the first cell at different preset temperatures is determined. The determined fitting relationship is used to indicate the relationship between the production line capacity and the cell temperature of the second cell after correction at different preset temperatures, so as to establish a model for correcting the production line capacity of the second cell at different preset temperatures.
[0008] According to the method of this application for correcting the production line capacity rating model of the second battery cell, by performing capacity rating on each first battery cell in each battery cell group at a corresponding preset temperature, the fitting relationship between the capacity rating and the average temperature of the first battery cell at the corresponding preset temperature is determined based on the capacity rating and average temperature of the first battery cell at the corresponding preset temperature. Then, the production line capacity rating component of the second battery cell at the corresponding preset temperature can be corrected based on the fitting relationship, so as to eliminate the changes in battery cell capacity caused by the fluctuation of ambient temperature during the capacity rating process (for example, the battery cell capacity is falsely high due to the high temperature during the capacity rating process in the workshop). This allows for obtaining a more accurate battery cell capacity, making the subsequent battery cell screening based on the battery cell capacity more reliable and consistent.
[0009] In some embodiments, the step of determining the fitting relationship between the fixed capacity and the average temperature of the first cell at different preset temperatures, based on the production line capacity of each first cell in each cell group and the average temperature and fixed capacity at corresponding preset temperatures, includes:
[0010] Based on the production line capacity of each first cell in each cell group and the average temperature and fixed capacity at the corresponding preset temperature, a first coefficient, a second coefficient, and a third coefficient are determined to determine the fitting relationship between the fixed capacity of the first cell and the average temperature at different preset temperatures. The first and second coefficients are used to eliminate the influence of the average temperature on the production line capacity, and the third coefficient is used to correct the production line capacity.
[0011] In some embodiments, the average temperature of the first cell at a corresponding preset temperature is the average of the starting temperature and the ending temperature of the first cell's electrode during the calibration process at the corresponding preset temperature.
[0012] Secondly, embodiments of this application provide a cell screening method based on cell capacity, comprising:
[0013] For each second cell in the same batch that has not been fixed after formation on the production line, capacity testing is performed at a preset temperature to determine the cell temperature and production line capacity testing capacity during the capacity testing process of each second cell at the preset temperature.
[0014] Based on the model established by the method in the first aspect and the preset temperature, the relationship between the production line capacity of the second cell after correction at the preset temperature and the cell temperature is determined.
[0015] Based on the relationship and the cell temperature of each second cell, the corrected production line capacity of each second cell is determined.
[0016] Based on the corrected production line capacity of each second cell, a first static capacity screening and a second dynamic capacity screening are performed on each second cell to determine whether each second cell is qualified.
[0017] According to the cell screening method based on cell capacity of this application, the production line capacity of the second cell is corrected based on the model established by the method in the first aspect, thereby enabling cell screening based on more accurate cell capacity and improving the reliability and consistency of the screened cells. Simultaneously, performing a first static capacity screening and a second dynamic capacity screening on each second cell can better avoid misjudgments caused by ambient temperature.
[0018] In some embodiments, the steps of performing a first static capacity screening and a second dynamic capacity screening on each second cell based on the corrected production line capacity allocation for each second cell include:
[0019] Based on the corrected production line capacity allocation for each second cell, determine the average static capacity Ave of a predetermined number of second cells. 静态 and static capacity standard deviation σ 静态 ;
[0020] Determine whether each second cell within the static preset number falls within the static capacity range X. 静态 Static capacity range X 静态 for:
[0021] Among them, Ave 静态 σ is the average static capacity of the second cell with a preset static number of cells. 静态 n is the standard deviation of the static capacity of the second cell, which is a statically preset number. 静态 For coefficients;
[0022] After determining that the second battery cell falls within the static capacity range X 静态 In this case, the second battery cell is determined to be qualified;
[0023] After determining that the second battery cell does not fall within the static capacity range X 静态 In this case, the second battery cell was determined to be substandard;
[0024] Repeat the above steps until all second cells in the same batch on the production line have been traversed, completing the initial static capacity screening for each second cell.
[0025] In some embodiments, the steps of performing a first static capacity screening and a second dynamic capacity screening on each second cell based on the corrected production line capacity allocation for each second cell include:
[0026] Based on the identification code of the second battery cell, the qualified second battery cells after the initial static capacity screening are arranged in sequence;
[0027] Based on the sequentially arranged second cells, starting from the smallest or largest identification code, a dynamically preset number of second cells are selected to determine the average dynamic capacity Ave of the dynamically preset number of second cells. 动态 and dynamic capacity standard deviation σ 动态 ;
[0028] Determine whether each second cell within the dynamically preset number falls within the dynamic capacity range X. 动态 Dynamic capacity range X 动态 for:
[0029] Among them, Ave 动态 σ is the average dynamic capacity of a dynamically preset number of second cells. 动态 n is the standard deviation of the dynamic capacity of a second cell with a dynamically preset number of cells. 动态 For coefficients;
[0030] After determining that the second battery cell falls within the dynamic capacity range X 动态 In this case, the second battery cell is determined to be qualified;
[0031] After determining that the second battery cell does not fall within the dynamic capacity range X 动态 In this case, the second battery cell was determined to be substandard;
[0032] Starting from the next identification code, retrieve the dynamically preset number of second cells again, and repeat the above steps until all qualified second cells after the first static capacity screening are traversed, thus completing the second dynamic capacity screening.
[0033] The qualified second cell after the second dynamic capacity screening is determined as the final qualified cell.
[0034] In some embodiments, the cell temperature during the capacity-limiting process of the second cell at a preset temperature is the average of the starting temperature and the ending temperature of the electrode of the second cell during the capacity-limiting process at the preset temperature.
[0035] In some embodiments, the functional formula for the relationship is:
[0036] ,
[0037] in, The production line capacity is adjusted for the second battery cell at a preset temperature.
[0038] The production line capacity of the second battery cell at a preset temperature;
[0039] This represents the average temperature of the second cell during the capacity testing process.
[0040] Preset temperature;
[0041] , , These are the first coefficient, the second coefficient, and the third coefficient, respectively.
[0042] In some embodiments, the dynamically preset number is greater than or equal to 100, and / or n 动态 The value range is 3 to 6, and / or the cell is a lithium-ion or sodium-ion cell.
[0043] In some embodiments, static capacity average Ave 静态 The average value of the corrected production line capacity for the statically preset number of second cells, and / or the average dynamic capacity Ave. 动态 The average value of the production line capacity after correction for the number of second cells dynamically preset. Attached Figure Description
[0044] Figure 1 A flowchart illustrating a method for modifying a production line capacity model for a second battery cell according to some embodiments of this application;
[0045] Figure 2 This illustrates the fitting relationships provided according to some embodiments of this application;
[0046] Figure 3 A flowchart illustrating a cell screening method based on cell capacity according to some embodiments of this application is shown;
[0047] Figure 4 This illustrates a flowchart of the initial static capacity screening provided according to some embodiments of this application;
[0048] Figure 5 This illustrates a flowchart of a secondary dynamic capacity filtering method provided according to some embodiments of this application;
[0049] Figure 6 This diagram illustrates a secondary dynamic capacity filtering method provided according to some embodiments of this application. Detailed Implementation
[0050] The specific embodiments of this application will now be described in detail with reference to the accompanying drawings.
[0051] Figure 1 A flowchart illustrating a method for modifying a production line capacity rating model for a second battery cell, according to some embodiments of this application, is shown. In a first aspect, as... Figure 1 As shown, this application provides a method for correcting the production line capacity rating model of a second battery cell, comprising the following steps:
[0052] Step S1: Determine the production line capacity of several first cells from the same batch that have not yet been formed and are not yet rated for capacity, and group them accordingly. The second cell is different from the first cell.
[0053] It should be noted that "first cell" can be understood as a cell from the same batch on the production line that has been formed and has been capacity-graded but has not yet been calibrated.
[0054] Step S2: Perform capacity setting on each cell group at different preset temperatures, and determine the average temperature and corresponding capacity setting of each first cell in each cell group during the capacity setting process at the corresponding preset temperature.
[0055] For example, the grouping value can range from 2 to 10, and each cell group includes at least 3 cells. The preset temperature can include multiple different temperature values or only one temperature value, without specific limitations, as long as it includes 25°C. That is, when the preset temperature includes multiple values, it must include at least 25°C and each temperature must be different; when the preset temperature includes only one value, the preset temperature is 25°C.
[0056] For example, such as Figure 2 As shown, the preset temperature can include 7 different temperature values, such as 16℃, 19℃, 22℃, 25℃, 28℃, 31℃, and 34℃. Several first-generation battery cells from the same batch are divided into 7 groups, such as first-generation battery cell group, second-generation battery cell group, third-generation battery cell group, fourth-generation battery cell group, fifth-generation battery cell group, sixth-generation battery cell group, and seventh-generation battery cell group. Each battery cell group includes 8 battery cells (e.g., ...). Figure 2 (Small black dot in the middle). Each cell group corresponds to a preset temperature. For example, the first cell group corresponds to 16℃, the second cell group corresponds to 19℃, ..., the seventh cell group corresponds to 34℃, thereby determining the average temperature and corresponding capacity of each first cell in the corresponding cell group during the capacity setting process at the corresponding preset temperature.
[0057] In some embodiments, the average temperature of the first cell during the capacitance process at a corresponding preset temperature can be the average of the starting temperature and the ending temperature of the first cell's electrode during the capacitance process at the corresponding preset temperature.
[0058] Step S3: Based on the production line capacity of each first cell in each cell group and the average temperature and constant capacity at the corresponding preset temperature, determine the fitting relationship between the constant capacity and the average temperature at different preset temperatures (e.g., Figure 2 As shown in the figure, the determined fitting relationship is used to indicate the relationship between the production line capacity of the second cell after correction at different preset temperatures and the cell temperature, so as to establish a model for correcting the production line capacity of the second cell at different preset temperatures.
[0059] According to the method of this application for correcting the production line capacity rating model of the second battery cell, by performing capacity rating on each first battery cell in each battery cell group at a corresponding preset temperature, the fitting relationship between the capacity rating and the average temperature of the first battery cell at the corresponding preset temperature is determined based on the capacity rating and average temperature of the first battery cell at the corresponding preset temperature. Then, the production line capacity rating component of the second battery cell at the corresponding preset temperature can be corrected based on the fitting relationship, so as to eliminate the changes in battery cell capacity caused by the fluctuation of ambient temperature during the capacity rating process (for example, the battery cell capacity is falsely high due to the high temperature during the capacity rating process in the workshop). This allows for obtaining a more accurate battery cell capacity, making the subsequent battery cell screening based on the battery cell capacity more reliable and consistent.
[0060] In some embodiments, the step of determining the fitting relationship between the fixed capacity and the average temperature of the first cell at different preset temperatures, based on the production line capacity of each first cell in each cell group and the average temperature and fixed capacity at corresponding preset temperatures, includes:
[0061] Based on the production line capacity rating of each first cell within each cell group, as well as the average temperature and fixed capacity at corresponding preset temperatures, a first coefficient, a second coefficient, and a third coefficient are determined to establish the fitting relationship between the fixed capacity and average temperature of the first cell at different preset temperatures. The first and second coefficients are used to eliminate the influence of average temperature on the production line capacity rating, while the third coefficient is used to correct the production line capacity rating. The specific fitting relationship will be described below.
[0062] Figure 3 A flowchart illustrating a cell screening method based on cell capacity according to some embodiments of this application is shown. Secondly, as... Figure 3 As shown, this application provides a cell screening method based on cell capacity, including the following steps:
[0063] Step S100: For each second cell of the same batch that has not been formed and has not been capacitated on the production line, capacity testing is performed at a preset temperature to determine the cell temperature and capacity testing capacity of each second cell during the capacity testing process at the preset temperature.
[0064] In some embodiments, the cell temperature during the capacity-balancing process of the second cell at a preset temperature can be the average of the starting temperature and the ending temperature of the second cell's terminals during the capacity-balancing process at the preset temperature. The capacity-balancing process can be a cell discharge process or a charging process, and is not specifically limited here.
[0065] Step S200: Based on the model established by the method in the first aspect and the preset temperature, determine the relationship between the production line capacity of the second cell after correction at the preset temperature and the cell temperature.
[0066] In some embodiments, the functional formula relating the production line capacity of the second cell after correction at a preset temperature to the cell temperature is as follows:
[0067] (1)
[0068] In formula (1),
[0069] The production line capacity is adjusted for the second battery cell at a preset temperature.
[0070] The production line capacity of the second battery cell at a preset temperature;
[0071] This represents the average temperature of the second cell during the capacity testing process.
[0072] Preset temperature;
[0073] , , These are the first coefficient, the second coefficient, and the third coefficient, respectively.
[0074] Step S300: Based on the relationship and the cell temperature of each second cell, determine the corrected production line capacity of each second cell.
[0075] In other words, by substituting the cell temperature (e.g., average temperature) of each second cell into the above formula (1), the corrected production line capacity of each second cell can be obtained.
[0076] Step S400: Based on the corrected production line capacity of each second cell, perform a first static capacity screening and a second dynamic capacity screening on each second cell to determine whether each second cell is qualified.
[0077] According to the cell screening method based on cell capacity of this application, the production line capacity of the second cell is corrected based on the model established by the method in the first aspect, thereby enabling cell screening based on more accurate cell capacity and improving the reliability and consistency of the screened cells. Simultaneously, performing a first static capacity screening and a second dynamic capacity screening on each second cell can better avoid misjudgments caused by ambient temperature.
[0078] In some embodiments, the first and second cells can be sodium-ion or lithium-ion cells. Since the capacity of sodium-ion or lithium-ion cells is highly sensitive to ambient temperature, correcting their capacity using the above method can yield a more accurate cell capacity, thereby further improving the reliability and consistency of the screened cells.
[0079] In some embodiments, reference Figure 4 Step S400 involves performing a first static capacity screening and a second dynamic capacity screening for each second cell based on the corrected production line capacity allocation for each second cell. Specifically, this may include the following steps:
[0080] Step S401: Based on the corrected production line capacity allocation for each second cell, determine the average static capacity Ave of a preset number of second cells. 静态 and static capacity standard deviation σ 静态 .
[0081] Step S402: Determine whether each second cell within the static preset number falls within the static capacity range X. 静态 Static capacity range X 静态 for:
[0082] Among them, Ave 静态 σ is the average static capacity of the second cell with a preset static number of cells. 静态 n is the standard deviation of the static capacity of the second cell, which is a statically preset number. 静态 is a coefficient.
[0083] Step S403, after determining that the second cell falls within the static capacity range X 静态 Under these circumstances, it was determined that the second battery cell was qualified.
[0084] Step S404: Determine that the second cell does not fall within the static capacity range X. 静态 In this case, it was determined that the second battery cell was substandard.
[0085] Step S405: Repeat the above steps until all second cells in the same batch on the production line have been traversed, completing the first static capacity screening of each second cell.
[0086] In some implementations, the static preset number can be the number of cells carried on a tray. 静态 The value range can be 3 to 6.
[0087] In some embodiments, reference Figure 5 Step S40 involves performing a first static capacity screening and a second dynamic capacity screening for each second cell based on the corrected production line capacity allocation for each second cell. This may further include the following steps:
[0088] Step S406: Based on the identification code (e.g., ID) of the second cell, arrange the qualified second cells after the initial static capacity screening in sequence. The sequence can be from largest to smallest or from smallest to largest.
[0089] Step S407: Based on the sequentially arranged second cells, select a dynamically preset number of second cells starting from the smallest or largest identification code, and determine the average dynamic capacity Ave of the dynamically preset number of second cells. 动态 and dynamic capacity standard deviation σ 动态 .
[0090] Step S408: Determine whether each second cell within the dynamically preset number falls within the dynamic capacity range X. 动态 Dynamic capacity range X 动态 for:
[0091] Among them, Ave 动态 σ is the average dynamic capacity of a dynamically preset number of second cells. 动态 n is the standard deviation of the dynamic capacity of a second cell with a dynamically preset number of cells. 动态 is a coefficient.
[0092] Step S409: After determining that the second cell falls within the dynamic capacity range X 动态 Under these circumstances, it was determined that the second battery cell was qualified.
[0093] Step S410: After determining that the second cell does not fall within the dynamic capacity range X 动态 In this case, it was determined that the second battery cell was substandard.
[0094] Step S411: Starting from the next identification code, retrieve the dynamically preset number of second cells again, and repeat the above steps until all qualified second cells after the first static capacity screening are traversed, thus completing the second dynamic capacity screening.
[0095] Step S412: Determine the qualified second cell after the second static capacity screening as the final qualified cell.
[0096] For example, refer to Figure 6 After the initial static capacity screening, the qualified second cells are arranged in ascending order. Starting from the smallest ID, a dynamically preset number (N) of second cells are selected, i.e., second cells with IDs from 1 to N are selected. The average dynamic capacity Ave of these N second cells is then determined. 动态-1 and dynamic capacity standard deviation σ 动态-1 After determining the N second cells, a new preset number (N) of second cells are selected starting from the next ID, i.e., cells with IDs from 2 to n+1 are selected, and the average dynamic capacity Ave of these N second cells is determined. 动态-2 and dynamic capacity standard deviation σ 动态-2After determining the N second cells, a new preset number (N) of second cells are selected starting from the next ID, i.e., cells with IDs from 3 to N+2 are selected, and the average dynamic capacity Ave of these N second cells is determined. 动态-3 and dynamic capacity standard deviation σ 动态-3 This process is repeated to complete the secondary dynamic capacity screening of all qualified second cells after the initial static capacity screening.
[0097] In some implementations, the number of dynamically preset values (N) is greater than or equal to 100. 动态 The value range can be 3 to 6.
[0098] According to the cell screening method based on cell capacity proposed in this application, by sorting cells and moving adjacent cells to determine their suitability, cells with poor consistency can be identified to a large extent. The movement determination focuses on local differences rather than global averages. This avoids local anomalies that might be masked by global statistical methods. For example, even if the overall cell parameter distribution is wide, sudden changes in the sequence can still be detected through adjacent comparisons, thus identifying "outlier" cells. In battery packs, cells are typically connected in series or parallel, and performance differences between adjacent cells directly affect the balance and efficiency of the battery pack. By sorting and comparing adjacent cells, this method simulates the actual operating state of cells in a battery pack, thus more effectively identifying cells that may be causing problems.
[0099] It should be noted that in the examples and description of this patent, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one" does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.
[0100] All methods and implementations of this application can be implemented in the form of software, magnetic files, firmware, etc.
[0101] Program code can be applied to input instructions to perform the functions described herein and generate output information. The output information can be applied to one or more output devices in a known manner. For the purposes of this application, the processing system includes any system having a processor such as, for example, a digital signal processor (DSP), a microcontroller, an application-specific integrated circuit (ASIC), or a microprocessor.
[0102] The program code can be implemented using a high-level procedural language or an object-oriented programming language to communicate with the processing system. Assembly language or machine language can also be used when needed. In fact, the mechanisms described in this paper are not limited to any particular programming language. In either case, the language can be a compiled language or an interpreted language.
[0103] One or more aspects of at least one embodiment can be implemented by representational instructions stored on a computer-readable storage medium, the instructions representing various logics in a processor, which, when read by a machine, cause the machine to create logic for performing the techniques described herein. These representations, referred to as “IP Cores,” can be stored on tangible computer-readable storage media and provided to multiple customers or production facilities for loading into manufacturing machines that actually manufacture the logic or processor.
[0104] In some cases, an instruction translator can be used to translate instructions from a source instruction set to a target instruction set. For example, an instruction translator can transform (e.g., using static binary transformation, including dynamically compiled dynamic binary transformation), morph, emulate, or otherwise translate instructions into one or more other instructions that will be processed by the IP core. Instruction translators can be implemented in software, hardware, firmware, or a combination thereof. Instruction translators can be on-processor, off-processor, or partially on-processor and partially off-processor.
[0105] Although this application has been illustrated and described with reference to certain preferred embodiments thereof, those skilled in the art should understand that various changes in form and detail may be made thereto without departing from the spirit and scope of this application.
Claims
1. A method for establishing a model for correcting the production line capacity allocation of a second battery cell, characterized in that, include: The production line capacity of several first cells that have not been fixed after formation in the same batch is determined and they are grouped together, wherein the second cell is different from the first cell; Each cell group is subjected to calibration at different preset temperatures to determine the average temperature and corresponding calibration capacity of each first cell in each cell group during the calibration process at the corresponding preset temperature. Based on the production line capacity of each first cell in each cell group, the average temperature and the fixed capacity at the corresponding preset temperature, the fitting relationship between the fixed capacity and the average temperature of the first cell at different preset temperatures is determined. The determined fitting relationship is used to indicate the relationship between the production line capacity and the cell temperature of the second cell at different preset temperatures, so as to establish a model for correcting the production line capacity of the second cell at different preset temperatures.
2. The method for establishing a model for correcting the production line capacity of the second battery cell according to claim 1, characterized in that, The step of determining the fitting relationship between the fixed capacity and the average temperature of the first cell at different preset temperatures, based on the production line capacity of each first cell in each cell group, the average temperature at a corresponding preset temperature, and the fixed capacity, includes: Based on the production line capacity of each first cell in each cell group, the average temperature at a corresponding preset temperature, and the fixed capacity, a first coefficient, a second coefficient, and a third coefficient are determined to determine the fitting relationship between the fixed capacity of the first cell and the average temperature at different preset temperatures. The first and second coefficients are used to eliminate the influence of the average temperature on the production line capacity, and the third coefficient is used to correct the production line capacity.
3. The method for establishing a model for correcting the production line capacity of the second battery cell according to claim 1, characterized in that, The average temperature of the first cell at the corresponding preset temperature is the average of the starting temperature and the ending temperature of the first cell's electrode during the calibration process at the corresponding preset temperature.
4. A cell screening method based on cell capacity, characterized in that, include: For each second cell in the same batch that has not been fixed after formation on the production line, capacity testing is performed at a preset temperature to determine the cell temperature and capacity testing capacity of each second cell during the capacity testing process at the preset temperature. Based on the model established by the method as described in any one of claims 1 to 3 and the preset temperature, the relationship between the production line capacity of the second cell after correction at the preset temperature and the cell temperature is determined. Based on the relationship and the cell temperature of each second cell, the corrected production line capacity of each second cell is determined. Based on the corrected production line capacity of each second cell, a first static capacity screening and a second dynamic capacity screening are performed on each second cell to determine whether each second cell is qualified.
5. The cell screening method based on cell capacity according to claim 4, characterized in that, Based on the corrected production line capacity allocation for each second cell, the steps of performing a first static capacity screening and a second dynamic capacity screening for each second cell include: Based on the corrected production line capacity allocation for each second cell, determine the average static capacity Ave of a predetermined number of second cells. 静态 and static capacity standard deviation σ 静态 ; Determine whether each of the second cells within the predetermined static number falls within the static capacity range X. 静态 The static capacity range X 静态 for: Among them, Ave 静态 σ is the average static capacity of the second cell with a preset static number of cells. 静态 n is the standard deviation of the static capacity of the second cell, which is a statically preset number. 静态 For coefficients; After determining that the second battery cell falls within the static capacity range X 静态 In this case, it is determined that the second battery cell is qualified; After determining that the second battery cell does not fall within the static capacity range X 静态 In this case, it is determined that the second battery cell is defective; Repeat the above steps until all the second cells in the same batch on the production line have been traversed, completing the initial static capacity screening for each second cell.
6. The cell screening method based on cell capacity according to claim 5, characterized in that, Based on the corrected production line capacity allocation for each second cell, the steps of performing a first static capacity screening and a second dynamic capacity screening for each second cell include: Based on the identification code of the second cell, the qualified second cells after the initial static capacity screening are arranged in sequence; Based on the sequentially arranged second battery cells, starting from the smallest or largest identification code, a dynamically preset number of second battery cells are selected to determine the average dynamic capacity Ave of the dynamically preset number of second battery cells. 动态 and dynamic capacity standard deviation σ 动态 ; Determine whether each of the second cells within the dynamically preset number falls within the dynamic capacity range X. 动态 The dynamic capacity range X 动态 for: Among them, Ave 动态 σ is the average dynamic capacity of a dynamically preset number of second cells. 动态 n is the standard deviation of the dynamic capacity of a second cell with a dynamically preset number of cells. 动态 For coefficients; After determining that the second battery cell falls within the dynamic capacity range X 动态 In this case, it is determined that the second battery cell is qualified; After determining that the second battery cell does not fall within the dynamic capacity range X 动态 In this case, it is determined that the second battery cell is defective; Starting from the next identification code, retrieve the dynamically preset number of second cells again, and repeat the above steps until all qualified second cells after the first static capacity screening are traversed, thus completing the second dynamic capacity screening; The qualified second cell after the second dynamic capacity screening is determined to be the final qualified cell.
7. The cell screening method based on cell capacity according to claim 4, characterized in that, The cell temperature of the second cell during the capacity separation process at the preset temperature is the average of the starting temperature and the ending temperature of the electrode of the second cell during the capacity separation process at the preset temperature.
8. The cell screening method based on cell capacity according to claim 4, characterized in that, The functional formula for the relationship is: in, The production line capacity is adjusted for the second battery cell at a preset temperature. The production line capacity of the second battery cell at a preset temperature; This represents the average temperature of the second cell during the capacity testing process. Preset temperature; , , These are the first coefficient, the second coefficient, and the third coefficient, respectively.
9. The cell screening method based on cell capacity according to claim 4, characterized in that, The number of dynamically preset values is greater than or equal to 100, and / or n 动态 The value range is 3 to 6, and / or the battery cell is a lithium-ion or sodium-ion battery cell.
10. The cell screening method based on cell capacity according to claim 5 or 6, characterized in that, The static capacity average value Ave 静态 The average value of the corrected production line capacity of the second cell of the statically preset number, and / or the average dynamic capacity Ave. 动态 The average value of the corrected production line capacity of the second battery cell of the dynamically preset number.