Battery cell state detection method, device and system and storage medium

Abstract

The invention provides a battery cell state detection method, device and system and a storage medium, and the method comprises the steps: obtaining a target polarization value of a to-be-detected battery cell, collecting the battery cell charging data of the to-be-detected battery cell in a formation stage if the polarization value of the to-be-detected battery cell reaches the target polarization value, and obtaining a first charging data set, and based on the first charging data set, determining the state type of the to-be-tested cell. Therefore, by acquiring the charging data of the battery cell in the period when the polarization value of the battery cell to be detected reaches the target polarization value in the formation stage and analyzing the state type of the abnormal battery cell based on the acquired charging data set, the abnormal battery cell caused by formation abnormality can be detected in time, the existing abnormal battery cell is screened out in advance, and the formation accuracy is improved. Moreover, the collected cell charging data correspond to the target polarization value position, and the accidental interference on the abnormal signal is small, thereby avoiding the misjudgment of a qualified cell as an abnormal signal, and improving the detection accuracy.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery detection, and in particular to a battery cell state detection method, device, system and storage medium. BACKGROUND

[0002] As core components of new energy application terminals and the like, the quality of batteries such as lithium ion batteries is directly related to the use experience and functional stability of terminal products, and the industry has increasingly strict requirements for the quality of batteries.

[0003] However, in the production of battery cells, problems such as abnormal film formation and uneven lithium intercalation may exist. Related detection methods are lagging behind, and are mostly dependent on post-formation capacity test, which is difficult to identify such hidden defects in advance, which leads to the flow of defective battery cells into the market, and the use process may face problems such as performance degradation and insufficient stability. Therefore, there is an urgent need for a technology that can accurately detect such abnormalities to achieve quality interception. SUMMARY

[0004] The present application provides a battery cell state detection method, device, system and storage medium, which detects the state of the battery cell during the formation stage, identifies abnormal battery cells in a timely manner, and ensures detection accuracy.

[0005] To achieve the above-mentioned purpose, the first aspect of the present application provides a battery cell state detection method, which comprises: obtaining a target polarization value of a battery cell to be tested; in the formation stage, if it is detected that the polarization value of the battery cell to be tested reaches the target polarization value, collecting battery cell charging data of the battery cell to be tested to obtain a first charging data set; the battery cell charging data comprises a battery cell current value; determining the state type of the battery cell to be tested according to the first charging data set; wherein the state type comprises normal or abnormal.

[0006] In the scheme provided by the present application, the collection of battery cell charging data is performed at the time when the polarization value of the battery cell to be tested reaches the target polarization value in the formation stage, and the state type analysis of abnormal battery cells is performed based on the collected charging data set, which can detect abnormal battery cells caused by formation abnormalities, and exclude abnormal battery cells with hidden problems such as uneven lithium intercalation and abnormal film formation in advance. The collected battery cell charging data corresponds to the target polarization value position, the abnormal signal is less affected by accidental interference, and the qualified battery cells can be avoided from being misjudged as abnormal, thereby improving the accuracy of detection.

[0007] In some optional embodiments, the obtaining the target polarization value of the to-be-tested battery cell comprises: obtaining a target state-of-charge parameter value of the to-be-tested battery cell; the target state-of-charge parameter value has a corresponding relationship with the target polarization value; and the collecting, in the formation stage, the battery cell charging data of the to-be-tested battery cell to obtain the first charging data set if it is detected that the polarization value of the to-be-tested battery cell reaches the target polarization value comprises: collecting, in the formation stage, the battery cell charging data of the to-be-tested battery cell to obtain the first charging data set if it is detected that the state-of-charge parameter value of the to-be-tested battery cell reaches the target state-of-charge parameter value.

[0008] In the scheme provided in the application, the target state-of-charge parameter value corresponding to the target polarization value of the to-be-tested battery cell can be obtained, so that the detection node is judged by detecting the state-of-charge parameter value related to the polarization value, the detection node can be monitored and positioned more efficiently, and the timeliness of data acquisition is improved.

[0009] In some optional embodiments, the obtaining the target state-of-charge parameter value of the to-be-tested battery cell comprises: charging a sample battery cell at a first preset charging rate to a first preset charging cutoff voltage, obtaining battery cell charging data of the sample battery cell to obtain a second charging data set, and determining the target state-of-charge parameter value of the to-be-tested battery cell according to the second charging data set.

[0010] In the scheme provided in the application, the corresponding relationship between the polarization value and the state-of-charge parameter value of the battery cell is determined by testing the sample battery cell, and the accuracy of determining the target polarization value and the target state-of-charge parameter value is improved.

[0011] In some optional embodiments, the second charging data set comprises a first battery cell voltage value and a battery cell cumulative charging electric quantity, the determining the target state-of-charge parameter value of the to-be-tested battery cell according to the second charging data set comprises: determining a differential voltage curve according to the battery cell voltage value and the battery cell cumulative charging electric quantity, obtaining a peak value in a preset voltage range in the differential voltage curve, the peak value corresponds to the polarization value of the to-be-tested battery cell, and the first battery cell voltage value corresponding to the peak value greater than a first preset threshold value is determined as the target state-of-charge parameter value of the to-be-tested battery cell.

[0012] In the scheme provided in the application, the differential voltage curve is drawn according to the battery cell voltage and the battery cell cumulative charging electric quantity in the charging data set of the sample battery cell, the target polarization value of the battery cell can be positioned more efficiently and accurately through the differential voltage curve, and the corresponding relationship between the polarization value and the voltage value is analyzed.

[0013] In some optional embodiments, the obtaining the peak value in the preset voltage range of the differential voltage curve comprises: filtering the differential voltage curve to obtain a target differential voltage curve; and obtaining the peak value in the preset voltage range of the target differential voltage curve.

[0014] In the scheme provided in the application, the differential voltage curve can be filtered to avoid noise interference in the original calculated differential curve, thereby affecting the accuracy of analysis. Based on the filtered target differential voltage curve, the peak value is analyzed and obtained, which can further improve the accuracy of the polarization value determination.

[0015] In some optional embodiments, the obtaining the target state-of-charge parameter value of the to-be-tested battery cell comprises: charging a plurality of sample battery cells with different initial electric quantities to a second preset charging cutoff voltage at a second preset charging rate, and obtaining battery cell charging data of the sample battery cells to obtain a third charging data set; and determining the target state-of-charge parameter value of the to-be-tested battery cell according to the third charging data set.

[0016] In the scheme provided in the application, a plurality of sample battery cells can be selected for testing and obtaining the correspondence between the state-of-charge parameter value and the polarization value. The sample battery cells are used for testing to determine the correspondence between the battery cell polarization value and the state-of-charge parameter value, which is beneficial to improving the accuracy of determining the target polarization value and the target state-of-charge parameter value.

[0017] In some optional embodiments, the third charging data set comprises a battery cell depolarization current and a second battery cell voltage value, and the determining the target state-of-charge parameter value of the to-be-tested battery cell according to the third charging data set comprises: determining a decay speed value of the battery cell depolarization current according to the battery cell depolarization current; and determining the second battery cell voltage value corresponding to the decay speed value reaching a preset speed threshold as the target state-of-charge parameter value of the to-be-tested battery cell.

[0018] In the scheme provided in the application, by analyzing the change trend of the depolarization current of the sample battery cell with different initial electric quantities in the charging process, the positioning of the maximum polarization value of the battery cell can be more efficiently and accurately realized, and the correspondence between the polarization value and the voltage value can be analyzed.

[0019] In some optional embodiments, the first charging data set further comprises a charging duration, and the determining the state type of the to-be-tested battery cell according to the first charging data set comprises: inputting the battery cell current value and the charging duration into a preset electrochemical diffusion model to obtain a current-time change curve; and determining the state type of the to-be-tested battery cell based on the current-time change curve.

[0020] In the scheme provided in the application, the original collected data is converted by adopting a preset electrochemical diffusion model to obtain a current-time change curve capable of reflecting the formation effect of the battery cell, and the internal state of the battery cell is focused, so that true and false abnormalities can be more accurately distinguished, misjudgments can be avoided, and the accuracy of the detection result can be effectively improved.

[0021] In some optional embodiments, the parameters of the electrochemical diffusion model include: a charging current, a battery cell structure coefficient, an interface liquid phase concentration difference change coefficient, a current change coefficient, and a comprehensive diffusion coefficient.

[0022] In the scheme provided in the application, the electrochemical diffusion model can be used to quantitatively analyze the mass transfer process in the battery cell by combining the current value, the inherent properties of the battery (such as the coefficient related to the structure of the battery cell and the comprehensive diffusion coefficient), and the process state quantity (such as the change amount of the liquid phase concentration difference at the interface and the coefficient related to the change of the current), which is helpful to understand the internal reason for the current decay.

[0023] In some optional embodiments, the state type of the battery cell under test is determined based on the current-time change curve, including: determining a curve slope value of a target linear region in the current-time change curve; and determining the state type of the battery cell under test according to the curve slope value.

[0024] In the scheme provided in the application, the state type of the battery cell is evaluated by the curve slope of the linear region in the current-time change curve converted by the electrochemical diffusion model. Since the curve slope is affected by the characteristic parameters of the mass transfer process of the battery cell in the model, the curve slope can represent the performance of the battery cell, thereby facilitating the improvement of the accuracy of the detection result of the state type of the battery cell.

[0025] In some optional embodiments, the state type of the battery cell under test is determined according to the curve slope value, including: obtaining a preset slope threshold range; if the curve slope value is within the preset slope threshold range, determining that the state type of the battery cell under test is normal; and if the curve slope value is outside the preset slope threshold range, determining that the state type of the battery cell under test is abnormal.

[0026] In the scheme provided in the application, the curve slope threshold value is compared with the preset slope threshold value, so that the battery cell with abnormal formation can be quickly screened out, and the detection efficiency is effectively improved.

[0027] In some optional embodiments, the target charging state parameter value is a target cell voltage value, and the formation stage of the to-be-tested cell includes: charging the to-be-tested cell to a first preset power threshold according to a first preset charging strategy; charging the to-be-tested cell to the target cell voltage value according to a third preset charging rate; performing constant voltage charging on the to-be-tested cell to a preset charging cutoff condition according to the target cell voltage value; charging the to-be-tested cell to a second preset power threshold according to a second preset charging strategy; and the second preset power threshold is greater than the first preset power threshold.

[0028] In the scheme provided in the application, by adopting different strategies in different formation stages, the target is accurately matched for each stage of formation, which is beneficial to improve the formation effect.

[0029] In some optional embodiments, the charging of the to-be-tested cell to the first preset power threshold according to the first preset charging strategy includes: applying a negative pressure to the to-be-tested cell to a preset negative pressure range; and charging the to-be-tested cell to each preset power according to a fourth preset charging rate corresponding to each preset power and a preset charging time length; and the preset power includes the first preset power threshold.

[0030] In the scheme provided in the application, the first preset charging strategy is to use a suitable charging rate and sufficient charging time length in different power stages, so as to achieve the target of SEI film formation and power accumulation, and avoid safety risks such as gas production, which is beneficial to improve the formation effect of the cell. The negative pressure treatment before charging can avoid problems such as deformation of the diaphragm or internal short circuit caused by gas accumulation, and is beneficial to better wetting of the electrolyte on the electrode material and improvement of the formation effect.

[0031] In some optional embodiments, the cell state detection method further includes: acquiring a first waiting time length corresponding to a negative pressure application event and a second waiting time length corresponding to each preset power, respectively; if the internal pressure value of the to-be-tested cell is in the preset negative pressure range, waiting for the first waiting time length; and if the power of the to-be-tested cell reaches the preset power, waiting for the second waiting time length.

[0032] In the scheme provided in the application, when each formation stage reaches the corresponding charging target, a preset time length is placed, and the gas can be fully discharged. By releasing the excess gas in time, the problems such as interface black spots caused by residual gas can be avoided to the greatest extent, and the film formation quality is guaranteed.

[0033] In some optional embodiments, the method further comprises: if the internal pressure value of the to-be-tested battery cell is in the preset negative pressure range, charging the to-be-tested battery cell according to a fifth preset charging rate and a third preset charging cutoff voltage value; and the fifth preset charging rate is smaller than any of the fourth preset charging rates.

[0034] In the scheme provided in the present application, the to-be-tested battery cell can be pre-charged at a low rate between the completion of negative pressure regulation and the start of constant current charging to a preset power threshold. The pre-charging at a low current and low voltage before formal formation can detect the wettability of the battery cell, avoid safety hazards in advance, and reduce subsequent risks.

[0035] The second aspect of the present application provides a battery cell state detection device, comprising: an acquisition module configured to acquire a target polarization value of a to-be-tested battery cell; a collection module configured to, in a formation stage, if it is detected that the polarization value of the to-be-tested battery cell reaches the target polarization value, collect battery cell charging data of the to-be-tested battery cell to obtain a first charging data set; the battery cell charging data comprises a battery cell current value; and a detection module configured to determine a state type of the to-be-tested battery cell according to the first charging data set; wherein the state type comprises normal or abnormal.

[0036] The third aspect of the present application provides a battery cell state detection system, comprising: a memory and a processor, wherein the processor is configured to execute a computer program stored in the memory, and when the processor executes the computer program, the battery cell state detection method provided in the first aspect of the present application is implemented.

[0037] The fourth aspect of the present application provides a computer readable storage medium, which stores a computer program, and when the computer program is executed by a processor, the battery cell state detection method provided in the first aspect of the present application is implemented.

[0038] It can be understood that the beneficial effects of the second aspect to the fourth aspect can be referred to the related description in the first aspect, which will not be repeated here. BRIEF DESCRIPTION OF DRAWINGS

[0039] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0040] Figure 1 A scene schematic diagram of a battery cell state detection method provided by some embodiments of the present application; Figure 2A flowchart of a method for detecting a state of an electric cell according to some embodiments of the present application; Figure 3 A flowchart of a method for detecting a state of an electric cell according to some embodiments of the present application; Figure 4 A flowchart of a method for detecting a state of an electric cell according to some embodiments of the present application; Figure 5 A schematic diagram of a differential voltage curve according to some embodiments of the present application; Figure 6 A flowchart of a method for detecting a state of an electric cell according to some embodiments of the present application; Figure 7 A schematic diagram of a first current-time curve according to some embodiments of the present application; Figure 8 A flowchart of a method for detecting a state of an electric cell according to some embodiments of the present application; Figure 9 A schematic diagram of a second current-time curve according to some embodiments of the present application; Figure 10 A schematic diagram of a third current-time curve according to some embodiments of the present application; Figure 11 A flowchart of a method for detecting a state of an electric cell according to some embodiments of the present application; Figure 12 A schematic diagram of a slope distribution of a curve of a mass-produced electric cell according to some embodiments of the present application; Figure 13 A flowchart of a method for detecting a state of an electric cell according to some embodiments of the present application; Figure 14 A flowchart of a method for detecting a state of an electric cell according to some embodiments of the present application; Figure 15 A schematic diagram of a module of a device for detecting a state of an electric cell according to some embodiments of the present application; Figure 16 A schematic diagram of a structure of a system for detecting a state of an electric cell according to some embodiments of the present application; Figure 17 A schematic diagram of a structure of a computer readable storage medium for storing or carrying program codes for implementing a method for detecting a state of an electric cell according to some embodiments of the present application. DETAILED DESCRIPTION

[0041] In order to make the objectives, characteristics, advantages of the present application more obvious and easy to understand, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0042] The following description refers to the accompanying drawings. Unless otherwise indicated, same or similar elements in different drawings are denoted by same or similar reference numerals. The implementation described in the following exemplary embodiments is not meant to represent all implementations consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with some aspects of the present application as detailed in the appended claims.

[0043] It should be understood that the term "comprising" as used in this specification and claims indicates the presence of the stated features, integers, steps, operations, elements, and / or components but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0044] It should also be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application. As used in this specification and the appended claims, the singular forms "a," "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0045] It should further be understood that the term "and / or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items, and that the term "at least one of" followed by a list of two or more items means any single one of the items in the list, and that the term "one or more of" followed by a list of two or more items means any single one or plurality of two or more of the items in the list.

[0046] In addition, in the description of the present application, the terms "first", "second", etc. are used only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features.

[0047] In the process of manufacturing the battery cell, formation is a key process for activating the battery cell, and directly determines the formation quality and subsequent performance of the SEI film (solid electrolyte interface film). The integrity and compactness of the SEI film not only affect the irreversible capacity loss of the battery cell, but also relate to the stability in long-term cycling.

[0048] The detection methods for formation abnormalities mainly rely on threshold judgment of macroscopic parameters such as voltage and time, or screening of defective products through capacity test after formation. These schemes have strong lag and insufficient precision. For example, the capacity test is performed after formation, the abnormal battery has consumed a large amount of production resources, and the problem source cannot be traced. Some hidden defects (such as unstable SEI film and uneven lithium intercalation) are difficult to show in the initial capacity test and will be gradually exposed with cycles. Purely using voltage threshold judgment is easily disturbed by environmental temperature and equipment fluctuation, and it is difficult to distinguish different abnormal types such as equipment contact failure and internal micro short circuit.

[0049] To solve the above problems, the battery state detection method, device, system and storage medium provided by the embodiments of the present application are provided. The target polarization value of the battery to be detected is obtained. In the formation stage, if it is detected that the polarization value of the battery to be detected reaches the target polarization value, the battery charging data of the battery to be detected is collected to obtain a first charging data set, and the state type of the battery to be detected is determined based on the first charging data set. The state type includes normal or abnormal. Therefore, by collecting the battery charging data in the period when the polarization value of the battery to be detected reaches the target polarization value in the formation stage, the state type analysis of the abnormal battery based on the collected charging data set can timely detect the abnormal battery caused by formation abnormality, and exclude the abnormal battery with hidden problems such as uneven lithium intercalation and film formation abnormality in advance. The collected battery charging data corresponds to the target polarization value position, the abnormal signal is less affected by accidental interference, and the qualified battery can be avoided to be misjudged as abnormal, thereby improving the detection accuracy.

[0050] The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. It should be noted that the description order of the following embodiments is not limited to the preferred order of the embodiments.

[0051] Please refer to Figure 1 , Figure 1 is a scene diagram of the battery state detection method provided by some embodiments of the present application. The scene mainly includes a battery to be detected 11 and a battery state detection system 12. The battery to be detected 11 is the detection object, and the battery state detection system 12 is used for detecting the battery to be detected 11.

[0052] Among them, the battery to be detected 11 (i.e. the battery to be formed) can be batch or single, and the battery to be detected 11 can be placed in a detection station as a unit (for example, 20 batteries are placed in a single tray), and each battery can be connected to the battery state detection system 12 through a tab clamp. The battery can be a cylindrical battery, a soft package battery, a square battery, etc.

[0053] The battery cell state detection system 12 can perform data acquisition, processing, and signal interaction, and can include a formation cabinet. The formation cabinet is used as a power source to supply power to the battery cell to be formed according to a preset formation process (such as constant current or constant voltage charging), and provides a data acquisition interface (connected to the positive and negative electrodes of the battery cell to acquire charging data such as current and voltage). The acquired data can be used to determine abnormal battery cells. If the formation cabinet has a high-performance processor that meets the processing requirements, data processing can be completed directly in the cabinet. If the formation cabinet has simple functions, an independent detection module (carrying a main control chip such as an MCU) can be externally connected to process data and output the determination result.

[0054] Please refer to Figure 2 , Figure 2 A flowchart of a battery cell state detection method provided for some embodiments of the present application is shown. In specific embodiments, the battery cell state detection method can be applied to a battery cell state detection scenario as shown in Figure 1 The specific process of the battery cell state detection method is as follows: S201, obtaining a target polarization value of a battery cell to be tested.

[0055] The polarization of the battery cell refers to the deviation between the actual electrode potential and the equilibrium potential during the charging and discharging process of the battery cell. The essence is the energy loss caused by the fact that the rate of the electrochemical process cannot keep up with the external current change. It is manifested as the deviation of the terminal voltage of the battery cell from the theoretical value, which is a phenomenon when the battery cell is working. For example, when the battery cell is charging and discharging, if the external current is large, lithium ions cannot be embedded, removed from the electrode, or migrated in the electrolyte, and electric charges will accumulate on the electrode surface, causing the actual potential to deviate from the equilibrium value. This deviation is called polarization.

[0056] During the formation stage of the battery cell, problems such as poor film formation and uneven lithium insertion can cause polarization of the battery cell. The polarization point can expose potential process abnormal battery cells. Different polarization value points may expose different types of abnormalities and sensitivities. For example, the abnormal signal strength at the maximum polarization point is higher, and the deviation threshold is significant, which is easy to identify directly and can easily expose potential process abnormal battery cells. Therefore, the target polarization value of the battery cell to be tested before detection can be the maximum polarization value. The maximum polarization value can be obtained through historical experience values or through testing.

[0057] S202, during the formation stage, if it is detected that the polarization value of the battery cell to be tested reaches the target polarization value, the battery cell charging data of the battery cell to be tested is acquired to obtain a first charging data set.

[0058] Formation is a core process in which a battery cell is converted from a physical assembly to a rechargeable battery cell. The core is to form a stable and dense SEI film (solid electrolyte interface film) on the surface of the negative electrode of the battery cell through a specific charging and discharging program, and to activate the electrochemical activity of the electrode material, thereby laying a foundation for the subsequent charging and discharging cycles and performance stability of the battery cell.

[0059] In the embodiment, by detecting whether the polarization value of the to-be-tested battery reaches the target polarization value during the formation stage of the to-be-tested battery, and collecting the charging data of the to-be-tested battery when the polarization value of the to-be-tested battery reaches the target polarization value, since there may be multiple polarization values meeting the condition during the formation stage of the to-be-tested battery, multiple battery charging data can be collected, and the types of the battery charging data can be battery charging voltage, battery current, etc. In a single collection, one or more types of battery charging data can be collected, and the collection frequency can be selected according to detection accuracy and other indicators.

[0060] S203, determining the state type of the to-be-tested battery according to the first charging data set.

[0061] In the embodiment, the state type (normal or abnormal) of the to-be-tested battery can be determined by the battery charging data (such as voltage curve, current curve, gas production data, temperature data, etc.) collected during the formation stage. The determination method can be to compare the actual data characteristics of the to-be-tested battery with the standard charging data characteristics, and determine that it is abnormal when the difference exceeds the threshold value, thereby achieving the purpose of quality screening of batteries in mass production. Moreover, since the battery charging data collected is collected at the node when the polarization value of the to-be-tested battery reaches the target polarization value, the polarization value point is the moment when the ion transmission and interface reaction resistance of the battery are significant, at which time the hidden problems such as uneven lithium intercalation and abnormal film formation in the formation process will be amplified, which can effectively filter accidental interference of the equipment or environment, avoid misjudging qualified batteries as abnormal, and improve the accuracy of detection.

[0062] Based on the technical solutions of the embodiments of the present application, by performing charging test on the sample battery and obtaining the battery voltage value corresponding to the target polarization value, if it is detected that the voltage value of the to-be-tested battery reaches the target battery voltage value during the formation stage, the battery charging data of the to-be-tested battery is collected to obtain a charging data set, the charging data set is input into a preset electrochemical diffusion model to obtain a target current-time curve, and by analyzing the curve slope value of the linear part of the curve, the state type of the to-be-tested battery, such as normal or abnormal, can be determined. Therefore, by collecting the battery charging data of the to-be-tested battery at the period when the polarization value of the to-be-tested battery reaches the target polarization value during the formation stage, and analyzing the state type of the abnormal battery based on the collected charging data set, the abnormal battery caused by formation abnormality can be detected in time, the abnormal battery with hidden problems such as uneven lithium intercalation and abnormal film formation can be screened out in advance, the battery charging data collected corresponds to the target polarization value position, the abnormal signal is less affected by accidental interference, and misjudgment of qualified batteries as abnormal can be avoided, thereby improving the accuracy of detection.

[0063] In the embodiments of the present application, during the formation stage, the strategy for determining the timing of collecting the battery charging data of the to-be-tested battery based on the polarization value of the to-be-tested battery can be various.

[0064] Please refer to Figure 3 , Figure 3 Another flowchart of an electrode state detection method provided by an embodiment of the present application is shown in FIG. 2B. Figure 3 In the embodiment shown in FIG. 2A, S2011 and S2021 are respectively Figure 2 In the embodiment shown in FIG. 2A, S2011 and S2021 are respectively

[0065] S2011, obtaining a target charging state parameter value of the electrode to be detected.

[0066] In the embodiment, the target charging state parameter value is in a corresponding relationship with a target polarization value. The change of the charging state parameter will cause the fluctuation of the polarization value, so that the polarization value corresponding to the electrode to be detected can be associated with multiple charging state parameters, such as the charging voltage of the electrode and the charging capacity of the electrode. Therefore, the polarization value of the electrode to be detected can also be represented by obtaining the charging state parameter value associated with the polarization value, for example, obtaining the target charging state parameter value corresponding to the target polarization value of the electrode to be detected.

[0067] S2021, in the formation stage, if it is detected that the charging state parameter value of the electrode to be detected reaches the target charging state parameter value, collecting the electrode charging data of the electrode to be detected to obtain a first charging data set.

[0068] In the embodiment, by detecting whether the polarization value of the electrode to be detected reaches the target polarization value in the formation stage of the electrode to be detected, and collecting the charging data of the electrode to be detected when the polarization value of the electrode to be detected reaches the target polarization value, in addition to the method of directly detecting the polarization value for judgment, the detection node can also be detected by detecting the charging state parameter value related to the polarization value. For example, it can be determined to perform charging data detection when it is detected that the charging state parameter value of the electrode to be detected reaches the target charging state parameter value corresponding to the target polarization value. By directly judging the charging state parameter value to locate the target polarization value, the detection node can be monitored and located more efficiently, which is beneficial to improve the timeliness of data collection.

[0069] In the embodiment of the present application, the target charging state parameter value of the electrode to be detected can be determined by using multiple strategies. Please refer to Figure 4 , Figure 4 Another flowchart of an electrode state detection method provided by an embodiment of the present application is shown in FIG. 2B. Figure 4 In the embodiment shown in FIG. 2B, S2011A to S2011B are respectively Figure 3 In the embodiment shown in FIG. 2B, S2011A to S2011B are respectively

[0070] S2011A, charging the sample electrode at a first preset charging rate to a first preset charging cutoff voltage, and obtaining the electrode charging data of the sample electrode to obtain a second charging data set; S2011B, determine the target charging state parameter value of the to-be-tested battery cell according to the second charging data set.

[0071] In this embodiment, the correspondence between the charging state parameter value and the polarization value can be obtained by testing a sample battery cell, wherein the sample battery cell is consistent with the to-be-tested battery cell in key dimensions such as generation batch, model, and formation process parameters. When testing the sample battery cell, a fixed current intensity can be used to continuously charge the sample battery cell. The current remains unchanged during the entire charging process, and the charging is stopped when the cell voltage reaches a preset charging cutoff voltage such as a maximum limit voltage Vmax. The current intensity can be determined by the charging rate, and the charging rate is the ratio of the charging current to the rated capacity of the battery cell (current = rate x capacity). For example, for a battery cell with a capacity of 1000 mAh, the charging rate is 0.5C, and the current is 500 mA. When testing the sample battery cell, a low rate (such as ≤0.04C) can be used to charge the sample battery cell, and the low rate charging is more gentle and less damaging to the battery cell.

[0072] During the charging process, the charging data of the sample battery cell can be collected in real time or at a preset frequency, and a charging data set is obtained, so that the charging state parameter value corresponding to the polarization value can be determined based on the charging data in the charging data set, and then the target charging state parameter value corresponding to the target polarization value of the to-be-tested battery cell is obtained. For example, the polarization value is calculated through real-time charging data, and the value of the charging state parameter corresponding to the polarization value is recorded, and an association table or curve of the polarization value and the charging state parameter can be established. By testing the sample battery cell, the correspondence between the polarization value of the battery cell and the charging state parameter value is determined, which is beneficial to improve the accuracy of determining the target polarization value and the target charging state parameter value.

[0073] In some embodiments, the second charging data set includes a first battery cell voltage value and a battery cell cumulative charging electric quantity, and the target charging state parameter value of the to-be-tested battery cell is determined according to the second charging data set, including: determining a differential voltage curve according to the battery cell voltage value and the battery cell cumulative charging electric quantity; obtaining a peak value in a preset voltage range in the differential voltage curve; wherein the peak value corresponds to the polarization value of the to-be-tested battery cell; determining the first battery cell voltage value corresponding to the peak value greater than the first preset threshold value as the target charging state parameter value of the to-be-tested battery cell.

[0074] In this embodiment, taking the charging state parameter as an example of the cell voltage, the process of determining the target charging state parameter value corresponding to the target polarization value according to the collected charging data of the sample cell is described. When the charging state parameter is the cell voltage, the data type of the collected charging data of the sample cell can be the cell voltage, the cumulative charging capacity of the cell (that is, the total amount of electricity charged into the cell from the charging time to the current time), so that the charging data set obtained contains these two types of charging data. The differential voltage value (dV / dQ) can be calculated according to the collected cell voltage (V) and the cumulative charging capacity of the cell (Q), that is, the change rate of the voltage to the capacity, and then the differential voltage curve can be drawn according to the differential voltage value (dV / dQ) and the cell voltage (V), for example Figure 5 as shown in Figure 5 , the abscissa is the cell voltage (V), and the ordinate is the differential voltage value (dV / dQ, that is, Value). The curve can reveal the electrochemical characteristics of the cell. For example, according to the peak value of the curve, the change of the polarization value can be analyzed, so that the peak value in the curve can be used to determine the cell voltage value corresponding to the target polarization value. When the target polarization value is the maximum polarization value, it can be determined that the target polarization value corresponds to the maximum peak value, that is, the target peak value greater than the preset threshold value or the target peak value of the maximum value of the obtained peak value, at this time the cell voltage value corresponding to the target polarization value can be determined, for example Figure 5 as shown in the curve is 3.36V. It should be noted that the collected charging data set contains the charging data of the entire charging process, and in a specific voltage range such as the early charging period, crystal structure changes (such as from hexagonal phase to monoclinic phase) may occur, at this time the voltage change is small, and the corresponding differential voltage curve will have a characteristic peak, which is not related to polarization, so this interference peak can be excluded, and the peak value acquisition and polarization analysis can be performed only in a specific voltage range. Therefore, according to the cell voltage (V) and the cumulative charging capacity of the cell (Q) in the charging data set of the sample cell, the differential voltage curve is drawn, and the target polarization value of the cell can be more efficiently and accurately located through the differential voltage curve, and the corresponding relationship between the polarization value and the voltage value is analyzed.

[0075] In some embodiments, the peak value in the preset voltage range of the differential voltage curve is obtained, including: filtering the differential voltage curve to obtain a target differential voltage curve; and obtaining the peak value in the preset voltage range of the target differential voltage curve.

[0076] In this embodiment, in order to more accurately capture the characteristic peaks of the differential voltage curve, for the differential voltage curve drawn according to the cell voltage (V) and the cell cumulative charge amount (Q) in the sample cell charging data set, a filtering process can also be performed on it to avoid noise interference in the original calculated differential curve and affect the accuracy of analysis. Filtering methods such as S-G filtering (Savitzky-Golay filtering), Gaussian filtering, etc. can be used to filter the original differential voltage curve. Among them, S-G filtering is a sliding window filtering method based on polynomial fitting, which uses a polynomial fitting curve in the neighborhood of each data point (such as the previous and next 5 points), and then replaces the original value with the value of the fitting curve. This filtering method can better preserve the characteristics such as peaks and inflection points of the curve (avoid over-smoothing leading to feature loss) while reducing noise. Gaussian filtering is a weighted average filtering method based on Gaussian function, which replaces the original value of each data point with the weighted average (the closer the distance, the greater the weight) of the surrounding points. The noise reduction effect of this filtering method is smoother, suitable for scenes with strong noise. According to actual filtering requirements, a corresponding filtering method can be selected to filter the original differential voltage curve. Based on the filtered target differential voltage curve, the peak value analysis and acquisition can be further improved the accuracy of the polarization value determination.

[0077] In the embodiments of the present application, a variety of strategies can be used to determine the target charging state parameter value of the to-be-tested cell. Please refer to Figure 6 , Figure 6 The flowchart of another cell state detection method provided by the embodiments of the present application is shown in Figure 6 S2011C to S2011D in Figure 3 another specific implementation method of S2011.

[0078] S2011C, according to the second preset charging rate, constant current charging a plurality of sample cells with different initial charge amounts to the second preset charging cutoff voltage, and obtaining the cell charging data of the sample cells to obtain a third charging data set; S2011D, determining the target charging state parameter value of the to-be-tested cell according to the third charging data set.

[0079] In the embodiment, the correspondence between the state-of-charge parameter value and the polarization value can be obtained by testing a sample battery, which is consistent with the key dimensions such as the generation batch, model, and formation process parameters of the battery to be tested. The selected sample battery can be one or more. When multiple sample batteries are selected, the multiple sample batteries can be sample batteries with different initial electric quantities, for example, the initial electric quantities of the multiple sample batteries are 10% SOC, 25% SOC, 60% SOC, and 100% SOC, respectively. 10% SOC means that the current state of charge (State of Charge) of the battery is 10%, that is, the current remaining electric quantity of the battery accounts for 10% of the rated capacity of the battery, which can measure the amount of electric quantity of the battery.

[0080] When testing multiple sample batteries with different initial electric quantities, a fixed current intensity can be used to charge the sample batteries. The current remains unchanged during the charging process, and the charging process stops when the battery voltage reaches a preset charging cutoff voltage such as a maximum limit voltage. The current intensity can be determined by the charging rate. When testing the sample batteries, a low rate (such as ≤0.04C) can be used to charge each sample battery. During the charging process, the charging data of each sample battery can be obtained in real time or at a preset frequency, and a charging data set is obtained. Based on the charging data in the charging data set, the charging state parameter value corresponding to the polarization value can be determined, and the target charging state parameter value corresponding to the target polarization value of the battery to be tested can be obtained. For example, the key charging data is extracted from the obtained charging data to calculate the polarization value, and the value of the charging state parameter corresponding to the polarization value is recorded, and an association table or curve of the polarization value and the charging state parameter can be established. By testing the sample battery, the correspondence between the polarization value of the battery and the charging state parameter value is determined, which is beneficial to improve the accuracy of determining the target polarization value and the target charging state parameter value.

[0081] In some embodiments, the third charging data set includes the battery depolarization current and the second battery voltage value. According to the third charging data set, the target charging state parameter value of the battery to be tested is determined, including: determining the decay speed value of the battery depolarization current according to the battery depolarization current; and determining the second battery voltage value corresponding to the decay speed value reaching the preset speed threshold as the target charging state parameter value of the battery to be tested.

[0082] In this embodiment, still taking the cell voltage as an example of the charging state parameter, the process of determining the target charging state parameter value corresponding to the target polarization value according to the charging data of sample cells with different initial capacities is described. When the charging state parameter is the cell voltage and the sample cells tested are multiple, the data type of the charging data of the sample cells collected can be the cell voltage and the cell depolarization current (a current component used to offset the polarization effect of the cell). The charging state and polarization characteristics of the cell can be determined according to the variation trend of the cell depolarization current of different sample cells, for example, the current-time variation curves of sample cells (such as lithium ion cells) with different initial capacities are drawn as shown in Figure 7 Figure 7 In the figure, the horizontal coordinate is the charging time (Time) and the vertical coordinate is the depolarization current (Current, unit: A). Among them, in the initial charging stage (0% to 60% SOC), the positive active material of the cell is in an unsaturated state, and the lithium ion insertion channel is sufficient. As the SOC increases, the lithium ion movement resistance increases, resulting in increased polarization, and the depolarization current shows an increasing trend. In the middle and late charging stage (60% to 100% SOC), the positive active material is close to saturation, and at this time the polarization has reached a high level. Due to the limited reaction rate, the depolarization current demand decreases, and the depolarization current shows a decreasing trend. Therefore, the polarization value can be analyzed by the variation trend of the depolarization current.

[0083] When the target polarization value is the maximum polarization value, it can be determined that the target polarization value corresponds to the position where the current decay rate is the slowest, that is, the position where the current decay rate reaches a large preset threshold value or the position of the minimum value among all decay rates. The cell voltage value at the time point corresponding to the position is obtained, and the target cell voltage value corresponding to the target polarization value is obtained. In the current-time curve diagram shown in Figure 7 The cell voltage corresponding to the minimum point of the depolarization current decay rate is 3.36V. By analyzing the variation trend of the depolarization current of sample cells with different initial capacities in the charging process, the positioning of the maximum polarization value of the cell can be more efficiently and accurately realized, and the corresponding relationship between the polarization value and the voltage value can be analyzed.

[0084] In the embodiments of the present application, there can be multiple strategies for determining the state type of the cell to be tested according to the first charging data set. Please refer to Figure 8 , Figure 8 for another flowchart of the cell state detection method provided in the embodiments of the present application, Figure 8 S2031 to S2032 in Figure 2 are a specific implementation method of S203 in

[0085] ​S2031, input the cell current value and charging time of the first charging data into the preset electrochemical diffusion model to obtain the current-time change curve; S2032 determines the state type of the battery cell under test based on the current-time variation curve.

[0086] In this embodiment, the cell charging data collected during the formation stage of the cell under test can be the cell current value. The collection time can also be recorded during data collection, and can be represented by the cumulative charging time corresponding to the current collection time. The state type of the cell under test can be analyzed by observing the trend of this current data. Furthermore, the current change trend can be observed from the current-time change curve of the cell current data and the corresponding time data, for example... Figure 9 The current-time variation curve shown is from Figure 9 As can be seen, with the increase of constant voltage charging time, the corresponding cell current slowly decreases, and the decreasing trend gradually stabilizes. However, it is difficult to evaluate the depolarization effect directly from this current-time change curve. The depolarization effect reflects the formation quality of the SEI film and the uniformity of the internal reaction of the cell during the formation stage. These two indicators can be used as evaluation criteria for the formation effect. Therefore, the raw data can be transformed, for example, by using a preset electrochemical diffusion model to transform the data format to obtain a current-time change curve that reflects the cell formation effect, which facilitates the analysis of the state type of the cell under test. By transforming the raw charging data and analyzing the cell formation effect, focusing on the internal state of the cell, it is possible to more accurately distinguish between true anomalies (problems with the cell itself) and false anomalies (external interference), avoid misjudgments, and improve the accuracy of the test results.

[0087] In some embodiments, the parameters of the electrochemical diffusion model include: charging current, cell structure coefficient, coefficient of variation of interfacial liquid phase concentration difference, coefficient of variation of current, and overall diffusion coefficient.

[0088] In this embodiment, the electrochemical diffusion model can be achieved by combining the current value I collected at the node where the cell polarization value meets the target polarization value with inherent battery properties (such as the coefficient α related to the cell structure and the comprehensive diffusion coefficient D) and process state quantities (such as the change in liquid phase concentration difference at the interface). The coefficient β, which is related to current changes, is used to quantify the mass transfer process (solid-phase or liquid-phase diffusion) within the battery cell, helping to understand the intrinsic reasons for current decay. The cell structure coefficient α can be determined by the cell's inherent properties (such as electrode thickness, porosity, and cell geometry), and the cell structure correction coefficients are generally consistent within the same batch of cells. The coefficient of change in liquid phase concentration difference at the interface (the surface where the cell electrode material contacts the electrolyte) is also relevant. the concentration difference of lithium ions in the electrolyte (liquid phase) in the data acquisition stage (e.g., the constant-voltage charging stage); the comprehensive diffusion coefficient D combines the solid-phase diffusion (the speed of lithium ions being embedded in or being separated from the electrode material) and the liquid-phase diffusion (the speed of lithium ions migrating in the electrolyte), and reflects the mass transfer efficiency of lithium ions in the battery; and the current change coefficient β describes the current change rate characteristics in the data acquisition stage. The electrochemical diffusion model can be expressed as: , t is the charging time. Through the model conversion, the nonlinear current-time change curve I-t curve can be converted into a target current-time change I-1 / curve with a linear part, such as the current-time change curve shown in Figure 10 ; wherein the abscissa is the time 1 / converted according to the electrochemical model, and the ordinate is the charging current I.

[0089] In the embodiments of the present application, there can be multiple strategies for determining the state type of the battery under test based on the current-time change curve. Please refer to Figure 11 , Figure 11 for another flowchart of the battery state detection method provided in the embodiments of the present application, Figure 11 S2032A to S2032B in Figure 8 are a specific implementation method of S2032 in

[0090] S2032A, determining the curve slope value of the target linear region in the current-time change curve; S2032B, determining the state type of the battery under test according to the curve slope value.

[0091] In the embodiments, the target current-time change curve obtained after the original current-time change curve is converted has a linear region, such as the current-time change curve shown in Figure 10 . In Figure 10 , the abscissa is the time 1 / converted according to the electrochemical model, and the ordinate is the charging current I. As can be seen from Figure 10 , in the early stage of constant-voltage charging (e.g., 0 to about 300 s, i.e., the right side 0.06 value 0.1 s part in Figure 10 ), the current decrease is mainly due to the liquid-phase depolarization, and in Figure 10 , the abscissa changes, showing a non-oblique line form; and after 300 s, the current slowly decreases, which is affected by the formation effect (e.g., film formation effect, uneven lithium embedding, etc.) of the battery (e.g., lithium-ion battery), and shows an oblique line form in Figure 10 . According to the principle of the model, it can be known that the curve slope of the linear part in the current-time change curve obtained after the conversion is affected by the battery structure coefficient , liquid phase concentration difference change , comprehensive diffusion coefficient and the data acquisition phase current change coefficient β, so the slope of the curve can be used as a quantitative indicator of the effect of the cell formation. Therefore, by calculating the slope value of the linear region of the curve, the state type of the to-be-tested battery can be determined.

[0092] The state type of the battery is evaluated by the slope of the linear region of the converted current-time change curve based on the electrochemical diffusion model. Since the slope is affected by the characteristic parameters of the mass transfer process of the battery in the model, the slope can represent the performance of the battery, thereby improving the accuracy of the detection result of the state type of the battery.

[0093] In some embodiments, according to the slope value, the state type of the to-be-tested battery is determined, including: obtaining a preset slope threshold range; if the slope value is within the preset slope threshold range, determining that the state type of the to-be-tested battery is normal; if the slope value is outside the preset slope threshold range, determining that the state type of the to-be-tested battery is abnormal.

[0094] In this embodiment, the specific implementation of determining the state type of the to-be-tested battery according to the slope value of the linear part of the target current-time change curve obtained by conversion can be to quickly determine the state of the to-be-tested battery by judging whether the obtained slope is within a preset reasonable interval (slope threshold range). The slope threshold range can be obtained by testing a large number of known normal batteries, recording the slope of the converted curve, and taking the average of these slopes ± a reasonable deviation as the threshold range to avoid misjudgment.

[0095] Since the first charging data set is collected at the target polarization value, if the to-be-tested battery is normal (such as normal film formation, uniform lithium intercalation concentration of graphite, etc.), the calculated slope value of the constant voltage charging stage should conform to the normal distribution range, and the slope values of the same batch of batteries should be highly consistent. If the following abnormalities occur during the battery formation process: such as film formation abnormality (such as film formation process due to abnormal water content, abnormal HF (hydrofluoric acid) content, etc. leading to excessive lithium consumption, resulting in abnormal film formation due to the failure of the graphite intercalation lithium amount at the target polarization value to reach the expected value), or uneven intercalation (such as insufficient graphite immersion, difficult intercalation, but the pre-set power has been charged, resulting in uneven intercalation of other fully immersed graphite higher than expected), etc., the calculated constant voltage charging stage current slope value will be significantly lower. Figure 12 The curve slope value distribution diagram is shown in the figure, Figure 12 The abscissa represents the battery data, and the ordinate is the curve slope value. The Figure 12The curve slope values corresponding to about 400 battery cells are provided. It can be seen that the current slope values of the plurality of battery cells to be tested are distributed in the preset range, but there are two obviously abnormal battery cells (whose slope values exceed the preset range). Through disassembly, it is found that the two battery cells have obvious local black spots (caused by local poor infiltration), and the black spot area fails to complete full film formation. In this case, if the subsequent use continues, it is easy to cause the risk of gas generation, the risk of interface lithium precipitation, and the risk of life deterioration. By comparing the calculated curve slope threshold value with the preset slope threshold value, when the batch detection of mass-produced battery cells is performed, the consistency of the curve slope can be compared, so that the battery cells with abnormal formation can be quickly screened out, and the detection efficiency is effectively improved.

[0096] In the embodiments of the present application, the formation stage of the battery cell to be tested can adopt a plurality of charging strategies. Please refer to Figure 13 , Figure 13 The flowchart of another battery cell state detection method provided by the embodiments of the present application is shown. In the embodiments, the target charging state parameter value is the target battery cell voltage value, and the charging strategy includes the following processes: S204, charging the battery cell to be tested to a first preset electric quantity threshold according to a first preset charging strategy; S205, charging the battery cell to be tested to a target battery cell voltage value according to a third preset charging rate; S206, performing constant voltage charging on the battery cell to be tested according to the target battery cell voltage value until a preset charging cutoff condition is met; S207, charging the battery cell to be tested to a second preset electric quantity threshold according to a second preset charging strategy.

[0097] In order to perform battery cell formation, the battery cell assembly needs to be completed in the preliminary preparation work, such as assembling electrode, separator, electrolyte and other raw materials into a sealed battery cell that can inject electrolyte, and injecting electrolyte into the battery cell through the injection port in a vacuum environment to ensure that the electrolyte fully infiltrates the electrode and the separator. High temperature (≥45℃) infiltration method can be used, and the battery cell is left for a preset time (≥15h) to ensure full infiltration and removal of bubbles to provide medium for electrochemical reaction.

[0098] In the formation stage, the measured battery after injection can be connected to the formation cabinet, and then the first preset charging strategy is used to charge it to the first preset power threshold, which can be the power point corresponding to the formation film stability, such as 15% SOC, reaching the end of gas production. Then further improve the lithium intercalation degree, continue to charge the measured battery at a preset charging rate until the target polarization value corresponding to the target charging state parameter value, such as the target battery voltage value, or the target power value. After the voltage or power value of the battery reaches the corresponding target value, a certain time period such as 2 minutes can be waited, and then the measured battery is charged in a constant voltage charging mode, and the constant voltage value can be the target battery voltage value corresponding to the target polarization value, such as 3.36V; the target battery voltage value is maintained during the constant voltage charging process, and the current is naturally attenuated until the current is reduced to a cutoff value (for example, 0.001C), or the constant voltage charging mode is directly used to charge for a preset time period (for example, 1h). Since the voltage value of the battery in this stage corresponds to the target polarization value, the battery charging data can be collected to obtain a charging data set containing a plurality of battery charging data. After the constant voltage charging reaches the charging cutoff condition, a preset time period such as 2 minutes can be waited, and then the second preset charging strategy is used to charge the measured battery to the second preset power threshold, that is, the second preset power threshold is greater than the first preset power threshold; the second preset power threshold can be used as the starting power point of the subsequent high-temperature aging program, and the second preset power threshold can be 70% SOC. The second preset charging strategy can be to charge the measured battery at a fourth preset charging rate, such as 0.33C, for a charging time period of 18 minutes. By using different strategies in different formation stages, the target precise matching process parameters for each stage of formation are beneficial to improve the formation effect.

[0099] In some embodiments, charging the measured battery to the first preset power threshold according to the first preset charging strategy includes: applying a negative pressure to the measured battery to a preset negative pressure range; and charging the measured battery to each preset power according to the fourth preset charging rate corresponding to each preset power and the preset charging time period; wherein the preset power includes the first preset power threshold.

[0100] In the process of charging the to-be-tested battery cell by adopting the first preset charging strategy to make the to-be-tested battery cell reach the first preset power threshold, mainly gradient current charging is performed, that is, gradually increasing the charging current, embedding more lithium ions into the negative electrode, fully activating the active material, and at the same time making the SEI film further thicken and stabilize. The charging power threshold can be used to divide each charging stage, and the charging rate, charging cutoff adjustment such as charging time for each charging power threshold can be set. The span of the power threshold can be set according to the actual situation, for example, the span is set to within 5% SOC, first charge the to-be-tested battery cell to 1.5% SOC according to the preset charging rate and charging time, and then preliminarily form the SEI film. Then adjust one or both of the charging rate and the charging time, charge to the next power threshold such as 3% SOC, and then adjust one or both of the charging rate and the charging time, charge to the next power threshold such as 5% SOC, and then adjust one or both of the charging rate and the charging time, charge to the next power threshold such as 8% SOC, adjust one or both of the charging rate and the charging time, and charge to the next power threshold such as 10% SOC. Adjust one or both of the charging rate and the charging time, and charge to the preset first power threshold such as 15% SOC. In the first preset charging strategy in the present embodiment, constant current charging is adopted throughout the charging process, and low rate (such as ≤0.05C) is adopted in the early charging stage (such as 0 to 10% SOC).

[0101] Exemplarily, the charging rate and the charging time corresponding to the above-mentioned power 1.25% SOC can be 0.05C and 15min respectively; the charging rate and the charging time corresponding to the above-mentioned power 3% SOC can be 0.05C and 21min respectively; the charging rate and the charging time corresponding to the above-mentioned power 5% SOC can be 0.05C and 24min respectively; the charging rate and the charging time corresponding to the above-mentioned power 8% SOC can be 0.05C and 36min respectively; the charging rate and the charging time corresponding to the above-mentioned power 10% SOC can be 0.05C and 24min respectively; and the charging rate and the charging time corresponding to the above-mentioned power 15% SOC can be 0.1C and 30min respectively. Thus, using appropriate charging rate and sufficient time at different power stages can achieve the goal of SEI film formation and power accumulation, and can also avoid safety risks such as gas production, which is beneficial to improve the effect of battery formation.

[0102] In addition, before charging the to-be-tested battery cell according to the first preset charging strategy, negative pressure needs to be applied to the battery, that is, vacuumizing the battery cell to make its internal pressure reach a preset negative pressure range such as -90 to -80 kPa. Making the battery in a negative pressure state is helpful to discharge the gas in the battery, avoid problems such as deformation of the separator or internal short circuit caused by gas accumulation, and also conducive to better wetting of the electrode material by the electrolyte, and improve the effect of formation.

[0103] In some embodiments, the method further comprises: obtaining a first waiting time corresponding to the negative pressure application event, and a second waiting time corresponding to each preset electric quantity; if the internal pressure value of the battery cell under test is in the preset negative pressure range, waiting for the first waiting time; if the electric quantity of the battery cell under test reaches the preset electric quantity, waiting for the second waiting time.

[0104] In this embodiment, the nodes at which the gas production reaches the preset value or the nodes at which the film forming abnormality caused by gas production is prone to occur can be rested to sufficiently remove the gas under negative pressure, for example, resting for a preset time in each charging stage, and the resting time can be adjusted according to the gas production, for example, resting for 10 to 30 seconds after the negative pressure adjustment is completed; resting for 10 minutes when charging to 1.25% SOC according to the preset charging rate; resting for 10 minutes when charging to 3% SOC according to the preset charging rate; resting for 10 minutes when charging to 5% SOC according to the preset charging rate; resting for 10 minutes when charging to 8% SOC according to the preset charging rate; resting for 10 minutes when charging to 10% SOC according to the preset charging rate; and resting for 5 minutes when charging to 15% SOC according to the preset charging rate. By releasing the excess gas in time, the interface black spot problem caused by gas residue can be avoided to the greatest extent, and the film forming quality is ensured.

[0105] In some embodiments, the method further comprises: if the internal pressure value of the battery cell under test is in the preset negative pressure range, charging the battery cell under test according to a fifth preset charging rate and a third preset charging cutoff voltage value; the fifth preset charging rate is less than any fourth preset charging rate.

[0106] In this embodiment, the battery cell under test can also be pre-charged at a low rate between the completion of negative pressure adjustment and the start of constant current charging to the preset electric quantity threshold, for example, pre-charging the battery cell under test at a charging rate (such as ≤0.02C) smaller than any charging rate in the first preset charging strategy and charging to a charging cutoff voltage such as 1.5V. By pre-charging the battery cell under test with low current and low voltage before formalization, the cell soaking effect can be detected, the safety hazard can be avoided in advance, and the subsequent risk can be reduced.

[0107] Based on the technical solutions of the above embodiments of the present application, the target polarization value of the to-be-tested battery cell is obtained, and in the formation stage, if it is detected that the polarization value of the to-be-tested battery cell reaches the target polarization value, the battery cell charging data of the to-be-tested battery cell is collected to obtain a first charging data set, and based on the first charging data set, the state type of the to-be-tested battery cell is determined, and the state type includes normal or abnormal. Therefore, by collecting the battery cell charging data in the period when the polarization value of the to-be-tested battery cell reaches the target polarization value in the formation stage, and based on the collected charging data set, the state type analysis of the abnormal battery cell is performed, the abnormal battery cell caused by the formation abnormality can be detected in time, the abnormal battery cell with hidden problems such as uneven lithium intercalation and film formation abnormality can be screened out in advance, the battery cell charging data collected corresponds to the target polarization value position, the abnormal signal is less affected by accidental interference, and the qualified battery cell can be avoided from being misjudged as abnormal, thereby improving the detection accuracy.

[0108] In order to better illustrate the battery cell state detection scheme in the foregoing embodiments, the present application further provides a refined battery cell state detection method, please refer to Figure 14 , Figure 14 which is a refined process schematic diagram of the battery cell state detection method provided by some embodiments of the present application, and includes the following steps: S301, according to a first preset charging rate, constant current charging is performed on a sample battery cell to a preset charging cutoff voltage, and battery cell charging data of the sample battery cell is obtained to obtain a first charging data set; S302, according to the battery cell voltage value and the battery cell cumulative charging capacity in the first charging data set, a differential voltage curve is determined, and a peak value in a preset voltage range is obtained; S303, the battery cell voltage value corresponding to the peak value greater than a preset threshold value is determined as a target battery cell voltage value corresponding to a target polarization value of the to-be-tested battery cell; S304, according to a preset charging strategy, the to-be-tested battery cell is charged to a preset capacity threshold value; S305, according to a second preset charging rate, the to-be-tested battery cell is charged to the target battery cell voltage value; S306, in the formation stage, if it is detected that the voltage value of the to-be-tested battery cell reaches the target battery cell voltage value, the battery cell charging data of the to-be-tested battery cell is collected to obtain a second charging data set; S307, the battery cell current value and the charging time length in the second charging data set are input into a preset electrochemical diffusion model to obtain a current-time change curve; S308, the curve slope value of a target linear region in the current-time change curve is determined; S309, according to the curve slope value, the state type of the to-be-tested battery cell is determined.

[0109] Based on the technical solution of the embodiment of the present application, the sample battery is tested for charging, and the battery voltage value corresponding to the target polarization value is obtained. In the formation stage, if the voltage value of the battery under test reaches the target battery voltage value, the battery charging data of the battery under test is collected to obtain a charging data set. The charging data set is input into a preset electrochemical diffusion model to obtain a target current-time curve. By analyzing the curve slope value of the linear part of the curve, the state type of the battery under test, such as normal or abnormal, can be determined. Thus, by collecting the battery charging data during the period when the polarization value of the battery under test reaches the target polarization value in the formation stage, and based on the collected charging data set, the state type analysis of the abnormal battery can be performed, the abnormal battery caused by formation abnormality can be detected in time, the abnormal battery with hidden problems such as uneven lithium intercalation and film formation abnormality can be screened out in advance, the abnormal signal is less affected by accidental interference because the collected battery charging data corresponds to the target polarization value position, and the qualified battery can be avoided from being misjudged as abnormal, thereby improving the detection accuracy.

[0110] It should be understood that the size of the serial number of each step in the embodiment does not mean the sequence of the execution of the steps. The execution sequence of each step should be determined according to its function and inherent logic, and should not constitute the only limitation on the implementation process of the embodiment of the present application.

[0111] Based on the same inventive concept, the present application also provides a related product for implementing the above method. It should be understood that the implementation scheme of the related product for solving the problem is similar to the above method.

[0112] The present application also provides a battery state detection device. Please refer to Figure 15 , Figure 15 A structural schematic diagram of a battery state detection device provided by some embodiments of the present application is shown in the figure. The battery state detection device 400 can include an acquisition module 401, a collection module 402, and a detection module 403, as follows: The acquisition module 401 is configured to acquire a target polarization value of a battery under test. The collection module 402 is configured to collect battery charging data of the battery under test to obtain a first charging data set if it is detected that the polarization value of the battery under test reaches the target polarization value. The battery charging data includes a battery current value. The detection module 403 is configured to determine a state type of the battery under test according to the first charging data set. The state type includes normal or abnormal.

[0113] In some embodiments, the acquisition module 401 can be configured to acquire a target charging state parameter value of the battery under test. The target charging state parameter value has a corresponding relationship with the target polarization value.

[0114] In some embodiments, the acquisition module 402 can be configured to: in the formation stage, if it is detected that the state-of-charge parameter value of the to-be-tested battery cell reaches a target state-of-charge parameter value, acquire the battery cell charging data of the to-be-tested battery cell to obtain a first charging data set.

[0115] In some embodiments, the acquisition module 401 can be further configured to: charge the sample battery cell at a first preset charging rate to a first preset charging cutoff voltage, and acquire the battery cell charging data of the sample battery cell to obtain a second charging data set; and determine the target state-of-charge parameter value of the to-be-tested battery cell according to the second charging data set.

[0116] In some embodiments, the second charging data set includes a first battery cell voltage value and a battery cell cumulative charging electric quantity, and the acquisition module 401 can be further configured to: determine a differential voltage curve according to the battery cell voltage value and the battery cell cumulative charging electric quantity; acquire a peak value in a preset voltage range in the differential voltage curve; wherein the peak value corresponds to a polarization value of the to-be-tested battery cell; and determine the first battery cell voltage value corresponding to the peak value greater than a first preset threshold value as the target state-of-charge parameter value of the to-be-tested battery cell.

[0117] In some embodiments, the acquisition module 401 can be further configured to: filter the differential voltage curve to obtain a target differential voltage curve; and acquire a peak value in a preset voltage range in the target differential voltage curve.

[0118] In some embodiments, the acquisition module 401 can be further configured to: charge a plurality of sample battery cells with different initial electric quantities at a second preset charging rate to a second preset charging cutoff voltage, and acquire the battery cell charging data of the sample battery cells to obtain a third charging data set; and determine the target state-of-charge parameter value of the to-be-tested battery cell according to the third charging data set.

[0119] In some embodiments, the third charging data set includes a battery cell depolarization current and a second battery cell voltage value, and the acquisition module 401 can be further configured to: determine an attenuation speed value of the battery cell depolarization current according to the battery cell depolarization current; and determine the second battery cell voltage value corresponding to the attenuation speed value reaching a preset speed threshold value as the target state-of-charge parameter value of the to-be-tested battery cell.

[0120] In some embodiments, the first charging data set further includes a charging duration, and the detection module 403 can be further configured to: input the battery cell current value and the charging duration into a preset electrochemical diffusion model to obtain a current-time change curve; determine the state type of the to-be-tested battery cell based on the current-time change curve; and the parameters of the electrochemical diffusion model include: a charging current, a battery cell structure coefficient, an interface liquid phase concentration difference change coefficient, a current change coefficient, and a comprehensive diffusion coefficient.

[0121] In some embodiments, the detection module 403 can be further configured to: determine a curve slope value of the target linear region in the current-time curve; and determine the state type of the battery under test according to the curve slope value.

[0122] In some embodiments, the detection module 403 can be further configured to: obtain a preset slope threshold range; determine that the state type of the battery under test is normal if the curve slope value is within the preset slope threshold range; and determine that the state type of the battery under test is abnormal if the curve slope value is outside the preset slope threshold range.

[0123] In some embodiments, the battery state detection apparatus can further include a charging control module configured to: charge the battery under test to a first preset charge threshold according to a first preset charging strategy; charge the battery under test to a target battery voltage value according to a third preset charging rate; perform constant voltage charging on the battery under test to a preset charging cutoff condition according to the target battery voltage value; charge the battery under test to a second preset charge threshold according to a second preset charging strategy; and wherein the second preset charge threshold is greater than the first preset charge threshold.

[0124] In some embodiments, the charging control module can be further configured to: apply a negative pressure to the battery under test to a preset negative pressure range; and charge the battery under test to each preset charge amount according to a fourth preset charging rate corresponding to each preset charge amount and a preset charging time length; wherein the preset charge amount includes the first preset charge threshold.

[0125] In some embodiments, the charging control module can be further configured to: obtain a first waiting time length corresponding to a negative pressure application event and a second waiting time length corresponding to each preset charge amount; wait for the first waiting time length if the internal pressure value of the battery under test is within the preset negative pressure range; and wait for the second waiting time length if the charge amount of the battery under test reaches the preset charge amount.

[0126] In some embodiments, the charging control module can be further configured to: charge the battery under test according to a fifth preset charging rate and a third preset charging cutoff voltage value if the internal pressure value of the battery under test is within the preset negative pressure range; and the fifth preset charging rate is less than any fourth preset charging rate.

[0127] It should be noted that the battery state detection method in the foregoing embodiments can be implemented based on the battery state detection apparatus provided in the present embodiment. Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the battery state detection apparatus described in the present embodiment can refer to the corresponding process in the foregoing method embodiments, which will not be described herein.

[0128] Based on the technical solutions of the above-mentioned embodiments of the present application, the target polarization value of the to-be-tested battery cell is obtained, and in the formation stage, if it is detected that the polarization value of the to-be-tested battery cell reaches the target polarization value, the battery cell charging data of the to-be-tested battery cell is collected to obtain a first charging data set, and based on the first charging data set, the state type of the to-be-tested battery cell is determined, and the state type includes normal or abnormal. Therefore, by collecting the battery cell charging data at the time when the polarization value of the to-be-tested battery cell reaches the target polarization value in the formation stage, and based on the collected charging data set, the state type analysis of the abnormal battery cell is performed, the abnormal battery cell caused by the formation abnormality can be detected in time, the abnormal battery cell with hidden problems such as uneven lithium intercalation and film formation abnormality can be screened out in advance, the battery cell charging data collected corresponds to the target polarization value position, the abnormal signal is less affected by accidental interference, and the qualified battery cell can be avoided to be misjudged as abnormal, thereby improving the detection accuracy.

[0129] In addition, the present application also provides a battery cell state detection system, please refer to Figure 16 , Figure 16 The structural schematic diagram of the battery cell state detection system provided for some embodiments of the present application, the battery cell state detection system 500 can be used to implement the battery cell state detection method in the foregoing embodiments, mainly including a processor 501 and a memory 502. Wherein, the processor 501 is electrically connected with the memory 502.

[0130] The processor 501 is the control center of the battery cell state detection system 500, and connects all parts of the battery cell state detection system through various interfaces and lines. By running or calling the computer programs stored in the memory 502 and calling the data stored in the memory 502, the processor 501 executes various functions and processes data of the battery cell state detection system, so as to perform overall monitoring on the battery cell state detection system.

[0131] The memory 502 can be used to store software programs and modules. The processor 501 executes various functions and data processing by running the computer programs and modules stored in the memory 502. The memory 502 can mainly include a program storage area and a data storage area. The program storage area can store an operating system, at least one computer program required by a function, etc.; the data storage area can store data created according to the use of the battery cell state detection system, etc.

[0132] In addition, the memory 502 can include a high-speed random access memory, and can also include a non-volatile memory, such as at least one magnetic disk storage device, a flash memory device, or other volatile solid-state memory device. Accordingly, the memory 502 can also include a memory controller to provide access of the processor 501 to the memory 502.

[0133] In the embodiment, the processor 501 in the battery cell state detection system 500 loads the instructions corresponding to the processes of one or more computer programs into the memory 502 according to the following steps, and runs the computer programs stored in the memory 502 by the processor 501, so as to realize various functions. For example, obtaining a target polarization value of a battery cell to be detected; in the formation stage, if it is detected that the polarization value of the battery cell to be detected reaches the target polarization value, collecting battery cell charging data of the battery cell to be detected to obtain a first charging data set; and determining a state type of the battery cell to be detected according to the first charging data set.

[0134] Please refer to Figure 17 which shows a structure diagram of a computer readable storage medium provided in the embodiment. The computer readable storage medium 600 stores program code 601, and the program code 601 can be called and executed by a processor to execute the method described in the above method embodiment.

[0135] The computer readable storage medium 600 can be an electronic storage such as a flash memory, an EEPROM (electrically erasable programmable read-only memory), an EPROM, a hard disk or a ROM. Alternatively, the computer readable storage medium 600 includes a non-transitory computer readable medium. The computer readable storage medium 600 has a storage space of the program code 601 for executing any method step in the above method. These program codes can be read from or written into one or more computer program products. The program code 601 can be compressed in an appropriate form, for example.

[0136] Since the instructions stored in the storage medium can execute the steps in any battery cell state detection method provided in the embodiments, the beneficial effects of any battery cell state detection method provided in the embodiments can be achieved. For details, please refer to the above embodiments, which will not be repeated here.

[0137] In several embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the modules is only a logical function division. In actual implementation, there can be another division manner, for example, a plurality of modules or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the displayed or discussed each other can be indirect coupling or communication connection through some interfaces, devices or modules, which can be electrical, mechanical or other forms.

[0138] The modules described as separate components may or may not be physically separate, and the components shown as modules may or may not be physical modules, i.e., may be located in one place, or may be distributed to multiple network modules. Part or all of the modules can be selected according to actual needs to achieve the purpose of the embodiment.

[0139] In addition, the functional modules in each embodiment of the present application can be integrated into one processing module, or each module can exist physically alone, or two or more modules can be integrated into one module. The integrated module can be realized in the form of hardware or in the form of a software functional module.

[0140] If the integrated module is realized in the form of a software functional module and sold or used as an independent product, it can be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the present application essentially or the part that contributes to the prior art or the whole or part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a readable storage medium, including a plurality of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the embodiments of the present application.

[0141] It should be noted that, for the foregoing method embodiments, in order to facilitate description, they are all expressed as a combination of a series of actions, but those skilled in the art should know that the present application is not limited by the order of the actions described, because according to the present application, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should know that the embodiments described in the specification all belong to preferred embodiments, and the actions and modules involved are not necessarily essential to the present application.

[0142] In the above embodiments, the description of each embodiment has its own emphasis, and the parts not described in detail in a certain embodiment can be referred to the related description of other embodiments.

[0143] The above is the description of the battery cell state detection method, device, system and storage medium provided by the present application. For those skilled in the art, according to the idea of the embodiments of the present application, there will be changes in specific implementation and application range. In conclusion, the content of the specification should not be understood as a limitation of the present application.

Claims

1. A method of detecting a state of an electric cell, characterized by, The method comprises: obtaining a target polarization value of a to-be-tested battery cell; in a formation stage, if it is detected that the polarization value of the to-be-tested battery cell reaches the target polarization value, collecting battery cell charging data of the to-be-tested battery cell to obtain a first charging data set; the battery cell charging data comprises a battery cell current value; determining a state type of the to-be-tested battery cell according to the first charging data set; the state type comprises normal or abnormal.

2. The battery cell state detection method according to claim 1, characterized by, The method comprises: obtaining a target charging state parameter value of the to-be-tested battery cell; the target charging state parameter value and the target polarization value have a corresponding relationship; in the formation stage, if it is detected that the charging state parameter value of the to-be-tested battery cell reaches the target charging state parameter value, collecting battery cell charging data of the to-be-tested battery cell to obtain a first charging data set. The method comprises:

3. The battery cell state detection method according to claim 2, characterized by, carrying out constant-current charging on a sample battery cell at a first preset charging rate to a first preset charging cutoff voltage, and obtaining battery cell charging data of the sample battery cell to obtain a second charging data set; determining the target charging state parameter value of the to-be-tested battery cell according to the second charging data set. The second charging data set comprises a first battery cell voltage value and a battery cell cumulative charging capacity; the method comprises:

4. The battery cell state detection method according to claim 3, characterized by, determining a differential voltage curve according to the battery cell voltage value and the battery cell cumulative charging capacity; obtaining a peak value in a preset voltage range in the differential voltage curve; the peak value corresponds to the polarization value of the to-be-tested battery cell; determining the first battery cell voltage value corresponding to the peak value greater than a first preset threshold value as the target charging state parameter value of the to-be-tested battery cell. The method comprises:

5. The battery cell state detection method according to claim 4, characterized by, filtering the differential voltage curve to obtain a target differential voltage curve; obtaining a peak value in a preset voltage range in the target differential voltage curve. The method comprises:

6. The battery cell state detection method according to claim 2, characterized by, carrying out constant-current charging on a plurality of sample battery cells with different initial capacities at a second preset charging rate to a second preset charging cutoff voltage, and obtaining battery cell charging data of the sample battery cells to obtain a third charging data set; determining the target charging state parameter value of the to-be-tested battery cell according to the third charging data set. The third charging data set comprises a battery cell depolarization current and a second battery cell voltage value; the method comprises:

7. The battery cell state detection method according to claim 6, wherein determining an attenuation speed value of the battery cell depolarization current according to the battery cell depolarization current; determining the second battery cell voltage value corresponding to the attenuation speed value reaching a preset speed threshold value as the target charging state parameter value of the to-be-tested battery cell. ​ 8. The battery cell state detection method according to claim 1, characterized by, The first charging data set further includes a charging duration, and the determining of the state type of the to-be-tested battery cell according to the first charging data set includes: inputting the battery cell current value and the charging duration into a preset electrochemical diffusion model to obtain a current-time change curve; determining the state type of the to-be-tested battery cell based on the current-time change curve.

9. The battery cell state detection method according to claim 8, wherein, The parameters of the electrochemical diffusion model include: a charging current, a battery cell structure coefficient, an interface liquid phase concentration difference change coefficient, a current change coefficient, and a comprehensive diffusion coefficient.

10. The battery cell state detection method according to claim 8, wherein The determining of the state type of the to-be-tested battery cell based on the current-time change curve includes: determining a curve slope value of a target linear region in the current-time change curve; determining the state type of the to-be-tested battery cell according to the curve slope value.

11. The battery cell state detection method according to claim 10, wherein The determining of the state type of the to-be-tested battery cell according to the curve slope value includes: obtaining a preset slope threshold range; if the curve slope value is in the preset slope threshold range, determining that the state type of the to-be-tested battery cell is normal; if the curve slope value is out of the preset slope threshold range, determining that the state type of the to-be-tested battery cell is abnormal.

12. The battery cell state detection method according to claim 2, wherein The target charging state parameter value is a target battery cell voltage value, and the formation stage of the to-be-tested battery cell includes: charging the to-be-tested battery cell to a first preset electric quantity threshold according to a first preset charging strategy; charging the to-be-tested battery cell to the target battery cell voltage value according to a third preset charging rate; performing constant voltage charging on the to-be-tested battery cell to a preset charging cutoff condition according to the target battery cell voltage value; charging the to-be-tested battery cell to a second preset electric quantity threshold according to a second preset charging strategy; the second preset electric quantity threshold is greater than the first preset electric quantity threshold.

13. The battery state detection method according to claim 12, wherein The charging of the to-be-tested battery cell to the first preset electric quantity threshold according to the first preset charging strategy includes: applying a negative pressure to the to-be-tested battery cell to a preset negative pressure range; charging the to-be-tested battery cell to each preset electric quantity according to a fourth preset charging rate corresponding to each preset electric quantity and a preset charging duration; the preset electric quantity includes the first preset electric quantity threshold.

14. The battery state detection method according to claim 13, wherein Further including: respectively obtaining a first waiting duration corresponding to a negative pressure application event and a second waiting duration corresponding to each preset electric quantity; if the internal pressure value of the to-be-tested battery cell is in the preset negative pressure range, waiting for the first waiting duration; if the electric quantity of the to-be-tested battery cell reaches the preset electric quantity, waiting for the second waiting duration.

15. The battery state detection method according to claim 13, wherein Further including: if the internal pressure value of the to-be-tested battery cell is in the preset negative pressure range, charging the to-be-tested battery cell according to a fifth preset charging rate and a third preset charging cutoff voltage value; the fifth preset charging rate is less than any fourth preset charging rate.

16. An electric cell state detecting apparatus characterized by comprising: including: an acquisition module, configured to acquire a target polarization value of a to-be-tested battery cell; a collection module, configured to, in a formation stage, if it is detected that a polarization value of the to-be-tested battery cell reaches the target polarization value, collect battery cell charging data of the to-be-tested battery cell to obtain a first charging data set; the battery cell charging data includes a battery cell current value; A detection module is configured to determine a state type of the battery cell to be tested according to the first charging data set, wherein the state type includes normal or abnormal.

17. A battery state detection system, characterized by, comprising a memory and a processor, wherein: the processor is configured to execute a computer program stored in the memory; the processor, when executing the computer program, implements the steps in the battery cell state detection method according to any one of claims 1 to 15.

18. A computer readable storage medium having stored thereon a computer program, characterized in that, the computer program, when executed by the processor, implements the steps in the battery cell state detection method according to any one of claims 1 to 15.

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