Battery cell detection method, device, computer equipment and storage medium

Abstract

The present application relates to a method, device, computer equipment and storage medium for detecting a battery cell. The method comprises: obtaining a target open circuit voltage of the battery cell after a wetting process; obtaining charging process data of the battery cell according to a preset charging process, and determining a target film-forming voltage of a solid electrolyte interface film in the battery cell according to the charging process data; determining a wetting detection result of the battery cell according to the target open circuit voltage and the target film-forming voltage; the wetting detection result is used to characterize whether the battery cell has a wetting abnormality. The present application can be used to perform battery cell detection in batches, with high detection efficiency, and can reduce the risk of missed kills.

Description

Technical Field

[0001] The present application relates to the technical field of battery cell detection, and in particular to a battery cell detection method, apparatus, computer equipment, and storage medium. Background Art

[0002] With the development of new energy technologies, lithium-ion batteries are widely used in various fields. During the production process, after injecting the electrolyte into the battery cell, a sufficient infiltration process is required. Insufficient infiltration can lead to interface anomalies such as dark marks and black spots during the formation and subsequent volume setting processes.

[0003] Currently, the industry mostly uses manual spot checks to determine whether battery cells are sufficiently soaked. However, this method only allows for a small number of checks, which can easily lead to missed batteries. Summary of the Invention

[0004] Based on the above problems, the present application provides a battery cell detection method, device, computer equipment and storage medium, which can perform battery cell detection in batches, have high detection efficiency, and reduce the risk of missing cells.

[0005] In the first aspect, the present application provides a battery cell detection method, which includes: obtaining the target open circuit voltage of the battery cell after the infiltration process; obtaining the charging process data of the battery cell according to a preset charging process, and determining the target film formation voltage of the solid electrolyte interface film in the battery cell based on the charging process data; determining the infiltration detection result of the battery cell based on the target open circuit voltage and the target film formation voltage; the infiltration detection result is used to characterize whether there is infiltration abnormality in the battery cell.

[0006] In the technical solution of the embodiment of the present application, whether there is wetting abnormality in the battery cell is determined based on the open circuit voltage and the film forming voltage, and the battery cell detection can be carried out in batches. Not only is the detection efficiency high and the risk of missing batteries can be reduced, but there is no need to disassemble the battery cells, thereby reducing various costs of detection investment.

[0007] In some embodiments, determining a cell wetting test result based on a target open-circuit voltage and a target film-forming voltage includes calculating the voltage difference between the target open-circuit voltage and the target film-forming voltage; if the voltage difference exceeds a preset voltage range, determining the cell wetting test result as abnormal wetting; wherein the preset voltage range is obtained by pre-calculating the voltage differences corresponding to multiple test samples. In the technical solution of the embodiments of the present application, using the voltage difference to determine whether a cell has abnormal wetting is more accurate than using either the target open-circuit voltage or the target film-forming voltage alone.

[0008] In some embodiments, determining a cell wetness detection result based on a target open-circuit voltage and a target film-forming voltage includes: determining a first detection result based on the target open-circuit voltage and a preset open-circuit voltage; determining a second detection result based on the target film-forming voltage and a preset film-forming voltage; determining a third detection result based on the voltage difference between the target open-circuit voltage and the target film-forming voltage; and determining the cell wetness detection result based on the first, second, and third detection results. In the technical solution of the embodiments of the present application, utilizing multiple detection results for detection can improve detection accuracy and reduce the risk of over- and under-detection.

[0009] In some embodiments, the charging process data includes the charging capacity and charging voltage at multiple charging moments, and determining the target film-forming voltage of the solid electrolyte interface film in the battery cell based on the charging process data includes: determining the charging capacity difference and charging voltage difference between each two adjacent charging moments based on the charging capacity and charging voltage at multiple charging moments; determining a differential capacitance curve based on the multiple charging capacity differences and charging voltage differences; extracting the peak voltage from a preset voltage interval of the differential capacitance curve, and determining the peak voltage as the target film-forming voltage of the solid electrolyte interface film in the battery cell. In the technical solution of the embodiment of the present application, by determining the differential capacitance curve based on the charging capacity and charging voltage, a more accurate target film-forming voltage can be extracted, providing an accurate basis for detecting the wetting effect, thereby improving the accuracy of battery cell detection.

[0010] In some embodiments, obtaining charging process data of a battery cell according to a preset charging process includes: controlling a charging device to perform constant current charging of the battery cell according to a preset charging rate and a preset charging duration; wherein the preset charging duration is determined based on a preset state of charge and a preset charging rate; and obtaining charging process data collected by the charging device during the charging process. In the technical solution of the embodiments of the present application, constant current charging of the battery cell according to a preset charging rate and a preset charging duration can minimize the impact of the polarization reaction on the film-forming voltage, thereby making the film-forming voltage more stable and thereby improving the accuracy of the infiltration detection.

[0011] In some embodiments, obtaining a target open circuit voltage of a battery cell after the soaking process includes: obtaining multiple raw open circuit voltages obtained by performing open circuit voltage tests on the battery cell after the soaking process, each time the battery cell is left to rest for a predetermined period of time; and determining a target open circuit voltage based on the multiple raw open circuit voltages. In the technical solution of the embodiments of the present application, multiple open circuit voltage tests can reduce test errors, improve the accuracy of the target open circuit voltage, and thereby improve the accuracy of soaking detection.

[0012] In some embodiments, determining a target open circuit voltage based on multiple raw open circuit voltages includes calculating an average open circuit voltage of the multiple raw open circuit voltages and determining the average open circuit voltage as the target open circuit voltage. In the technical solution of the embodiments of the present application, using the average voltage value as the target open circuit voltage can reduce test errors, improve the accuracy of the target open circuit voltage, and thereby improve the accuracy of infiltration detection.

[0013] In a second aspect, the present application further provides a battery cell detection device, the device comprising:

[0014] The open circuit voltage acquisition module is used to obtain the target open circuit voltage of the battery cell after the soaking process;

[0015] A film formation voltage acquisition module is used to obtain charging process data of the battery cell according to a preset charging process, and determine the target film formation voltage of the solid electrolyte interface film in the battery cell based on the charging process data;

[0016] The wetting detection module is used to determine the wetting detection result of the battery cell based on the target open circuit voltage and the target film forming voltage; the wetting detection result is used to characterize whether there is wetting abnormality in the battery cell.

[0017] In a third aspect, the present application further provides a computer device comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements any one of the methods in the first aspect when executing the computer program.

[0018] In a fourth aspect, the present application further provides a computer-readable storage medium having a computer program stored thereon, which implements any one of the methods in the first aspect when the computer program is executed by a processor.

[0019] In a fifth aspect, the present application further provides a computer program product, comprising a computer program, which implements any one of the methods in the first aspect when executed by a processor. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the optional embodiments below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present application. The same reference numerals are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0021] Figure 1 Schematic diagram of an application environment of a battery cell detection method according to an embodiment of the present application;

[0022] Figure 2 1 is a flow chart of a battery cell detection method according to an embodiment of the present application;

[0023] Figure 3Schematic diagram showing the change of open circuit voltage with immersion time according to an embodiment of the present application;

[0024] Figure 4 1 is a flow chart of the step of determining the infiltration detection result according to an embodiment of the present application;

[0025] Figure 5a is a schematic diagram of a voltage difference according to an embodiment of the present application;

[0026] Figure 5b is a schematic diagram of a preset voltage range according to an embodiment of the present application;

[0027] Figure 6 is a flowchart of the step of determining the infiltration detection result in another embodiment of the present application;

[0028] Figure 7 1 is a flow chart of the step of determining the target film forming voltage according to one embodiment of the present application;

[0029] Figure 8 is a schematic diagram of a differential capacitance curve according to an embodiment of the present application;

[0030] Figure 9 This is a flowchart of the steps for obtaining charging process data according to an embodiment of the present application;

[0031] Figure 10 1 is a flow chart of the step of obtaining the target open circuit voltage according to an embodiment of the present application;

[0032] Figure 11 This is a structural block diagram of a battery cell detection device according to an embodiment of the present application;

[0033] Figure 12 It is a diagram of the internal structure of a computer device according to an embodiment of the present application. DETAILED DESCRIPTION

[0034] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0036] In the description of the embodiments of this application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood to indicate or imply relative importance or implicitly specify the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0037] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0038] In the description of the embodiments of this application, the term "and / or" is simply a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0039] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0040] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; internal connections between two components or interactions between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present application based on specific circumstances.

[0041] With the development of new energy technologies, lithium batteries are widely used in various fields. During the production process of lithium batteries, after injecting the electrolyte into the battery cell, a sufficient infiltration process is required. If the infiltration is insufficient, it will lead to interface abnormalities such as dark marks and black spots on the interface during the formation and subsequent volume setting process. Currently, the industry mostly uses manual sampling to determine whether the battery cell is sufficiently infiltrated and whether it will cause interface abnormalities. However, this method has a small number of samplings and is prone to missing products.

[0042] In response to the above-mentioned problems, an embodiment of the present application provides a battery cell detection solution, which obtains the target open circuit voltage of the battery cell after the infiltration process; obtains the charging process data of the battery cell according to a preset charging process, and determines the target film-forming voltage of the solid electrolyte interface film in the battery cell based on the charging process data; and determines whether the battery cell has an infiltration abnormality based on the target open circuit voltage and the target film-forming voltage. In the technical solution of the embodiment of the present application, the presence of an infiltration abnormality in the battery cell is determined based on the open circuit voltage and the film-forming voltage, and battery cell detection can be performed in batches. Not only is the detection efficiency high, which can reduce the risk of missing, but also there is no need to disassemble the battery cell, that is, non-destructive screening is achieved, and thus the various costs of detection investment can be reduced.

[0043] The battery cell detection method provided in the embodiment of the present application can be applied to Figure 1 In the application environment shown. The application environment includes a computer device 101, a charging device 102, and a testing device 103, wherein the computer device 101 can communicate with the charging device 102 and the testing device 103 via a network. After connecting to the battery cell, the charging device 102 can charge the battery cell and collect data during the charging process. The testing device 103 can test the battery cell and obtain the open circuit voltage of the battery cell. The computer device 101 can obtain the charging process data collected by the charging device 102 and the open circuit voltage detected by the testing device 103.

[0044] According to some embodiments of the present application, referring to Figure 2 , provides a battery cell detection method, which is applied to Figure 1 Taking the computer device in the example as an example, the embodiment of the present application may include the following steps:

[0045] Step 201 : obtaining a target open circuit voltage of the battery cell after the soaking process.

[0046] Among them, open circuit voltage (OCV) refers to the terminal voltage of the battery cell in the open circuit state.

[0047] The final steps in battery cell production include: cell casing, top cover welding, baking, liquid injection, high-temperature soaking, formation, secondary liquid injection, and high-temperature aging. After the high-temperature soaking process, the cells are left to rest for a period of time before being tested using testing equipment to determine the target open-circuit voltage. Computer equipment can obtain the target open-circuit voltage from the testing equipment.

[0048] Step 202 : acquiring charging process data of the battery cell according to a preset charging process, and determining a target film-forming voltage of a solid electrolyte interface (SEI) film in the battery cell based on the charging process data.

[0049] After the test, the battery cells are charged using a charging device according to a preset charging process, and data is collected during the charging process to obtain charging process data. During the charging process, the SEI film forms inside the battery cells, and the charging process data includes the battery cell voltage when the SEI film forms.

[0050] The computer device can obtain charging process data from the charging device. The computer device then processes the charging process data and analyzes the processed data using a preset algorithm to determine the cell voltage at which the SEI film forms within the battery cell. This cell voltage is then determined as the target film formation voltage. This data processing may include removing abnormal data points.

[0051] In some embodiments, the charging voltage can be increased at a constant rate during the charging process of the battery cell. Afterwards, data processing is performed based on the charging process data, and a preset algorithm is used to generate a CV (current-voltage) curve based on the processed data, and then the target film-forming voltage is determined based on the CV curve.

[0052] Step 203 : determining the wetness detection result of the battery cell according to the target open circuit voltage and the target film forming voltage.

[0053] Among them, the infiltration detection results are used to characterize whether there is infiltration abnormality in the battery cell.

[0054] Statistics of a large number of infiltration experimental data show that after the electrolyte is injected into the battery cell, the cathode and anode current collectors and the cathode and anode active substances begin to establish a solid-liquid surface potential with the liquid phase. The solid-liquid surface potential increases with the increase of the infiltration degree (the effective area of ​​the electrolyte infiltrating the cathode and anode current collectors and the cathode and anode active substances). The solid-liquid surface potential changes regularly, which is reflected in the open circuit voltage (OCV) of the battery cell: the OCV of the battery cell gradually decreases and tends to a stable state, such as Figure 3 As shown, the horizontal axis is the immersion time, in hours (h); the vertical axis is the open circuit voltage, in millivolts (mV).

[0055] Furthermore, statistical analysis of extensive wetting experiment data reveals that a solid-liquid electrolyte interphase (SEI) forms on the graphite surface during the first charge of a battery cell. For a specific battery cell formulation and design, the SEI film formation voltage during the charging phase is stable. Abnormal SEI film formation voltage indicates wetting anomalies, or excessive water content or other impurities in the battery cell. These issues can also lead to abnormalities in the fully charged interface after aging.

[0056] Based on the above data statistics, after obtaining the target open-circuit voltage and target film-forming voltage, the embodiment of the present application can compare the target open-circuit voltage with the reference open-circuit voltage, and compare the target film-forming voltage with the reference film-forming voltage. Then, based on the comparison results, it is determined whether the battery cell has abnormal wetting, thereby determining whether the battery cell has abnormalities at the full charge interface after aging.

[0057] In the above embodiment, the target open circuit voltage of the battery cell after the infiltration process is obtained; the charging process data of the battery cell according to the preset charging process is obtained, and the target film-forming voltage of the solid electrolyte interface film in the battery cell is determined based on the charging process data; and the presence of infiltration anomalies in the battery cell is determined based on the target open circuit voltage and the target film-forming voltage. In the technical solution of the embodiment of the present application, the presence of infiltration anomalies in the battery cell is determined based on the open circuit voltage and the film-forming voltage, and the battery cell detection can be carried out in batches. Not only is the detection efficiency high and the risk of missing kills can be reduced, but there is no need to disassemble the battery cell, thereby reducing various costs of detection investment.

[0058] According to some embodiments of the present application, referring to Figure 4 In the above embodiment, “determining the wetting detection result of the battery cell according to the target open circuit voltage and the target film forming voltage” may include the following steps:

[0059] Step 301 : Calculate the voltage difference between the target open circuit voltage and the target film forming voltage.

[0060] For example, the target open circuit voltage is V OCV , the target film forming voltage is V SEI , then the voltage difference is ΔE=V SEI -V OCV .

[0061] Step 302 : If the voltage difference exceeds the preset voltage range, it is determined that the result of the cell wetting detection is that the cell has a wetting abnormality.

[0062] The preset voltage range is obtained by pre-statistically analyzing voltage differences corresponding to a plurality of test samples.

[0063] Pre-calculate the voltage difference corresponding to multiple test products, refer to Figure 5a The horizontal axis is the battery cell number, and the vertical axis is the voltage difference, in mV; the figure shows the voltage difference of 20,000 battery cells.

[0064] In practical applications, a variety of methods can be used to perform statistical analysis on the voltage difference of the test sample to obtain the preset voltage range. For example, the upper and lower limits of the voltage difference are calculated by using the mean value ± 3σ to obtain the preset voltage range. Figure 5b .

[0065] After obtaining the voltage difference of the battery cell, determine whether the voltage difference exceeds the preset voltage range. If the voltage difference exceeds the preset voltage range, indicating that the target open circuit voltage and / or target film-forming voltage of the battery cell are abnormal, it can be determined that the result of the infiltration detection of the battery cell is that the battery cell has an infiltration abnormality, which is likely to cause abnormalities in the full charge interface of the battery cell after aging. If the voltage difference does not exceed the preset voltage range, indicating that the target open circuit voltage and target film-forming voltage of the battery cell are normal, it can be determined that the result of the infiltration detection of the battery cell is that the battery cell does not have an infiltration abnormality, which is not likely to cause abnormalities in the full charge interface of the battery cell after aging.

[0066] In the above embodiment, the voltage difference between the target open-circuit voltage and the target film-forming voltage is calculated; if the voltage difference exceeds a preset voltage range, the cell wetting detection result is determined to indicate a wetting anomaly. In the technical solution of the present embodiment, using the voltage difference to determine whether a cell has a wetting anomaly is more accurate than using either the target open-circuit voltage or the target film-forming voltage alone.

[0067] According to some embodiments of the present application, referring to Figure 6 In the above embodiment, “determining the wetting detection result of the battery cell according to the target open circuit voltage and the target film forming voltage” may include the following steps:

[0068] Step 401: Determine a first detection result according to a target open circuit voltage and a preset open circuit voltage.

[0069] Based on the trend of the battery cell OCV changing with the soaking time, a preset open circuit voltage can be determined. After obtaining the target open circuit voltage, the target open circuit voltage is compared with the preset open circuit voltage. If the target open circuit voltage is less than or equal to the preset open circuit voltage, it indicates that the trend of the target open circuit voltage of the battery cell changing with the soaking time is normal, and the first detection result is determined to be that there is no soaking abnormality in the battery cell. If the target open circuit voltage is greater than the preset open circuit voltage, it indicates that the trend of the target open circuit voltage of the battery cell changing with the soaking time is abnormal, and the first detection result is determined to be that there is a soaking abnormality in the battery cell.

[0070] It should be noted that different immersion times correspond to different preset open circuit voltages.

[0071] Step 402 : Determine a second detection result according to the target film forming voltage and the preset film forming voltage.

[0072] For a specific battery cell formula and design, the SEI film formation voltage during the charging phase is a stable value. The SEI film formation voltage in historical data can be statistically analyzed to obtain a preset film formation voltage.

[0073] After obtaining the target film-forming voltage, the target film-forming voltage is compared with the preset film-forming voltage. If the target film-forming voltage is less than or equal to the preset film-forming voltage, indicating that the target film-forming voltage of the battery cell is normal, the second detection result is determined to be that the battery cell does not have a wetting abnormality. If the target film-forming voltage is greater than the preset film-forming voltage, indicating that the target film-forming voltage of the battery cell is abnormal, the second detection result is determined to be that the battery cell does have a wetting abnormality.

[0074] Step 403 : determining a third detection result according to the voltage difference between the target open circuit voltage and the target film forming voltage.

[0075] Referring to the above embodiment, the voltage difference between the target open circuit voltage and the target film forming voltage is calculated. If the voltage difference exceeds the preset voltage range, the third detection result is determined to be that there is a wetting abnormality in the battery cell; if the voltage difference is within the preset voltage range, the third detection result is determined to be that there is no wetting abnormality in the battery cell.

[0076] Step 404 : Determine the infiltration detection result of the battery cell according to the first detection result, the second detection result, and the third detection result.

[0077] After obtaining the first, second, and third test results, the infiltration detection result of the battery cell can be determined in a variety of ways. For example, if any one of the first, second, and third test results indicates that the battery cell has an infiltration abnormality, the infiltration detection result of the battery cell is determined to be an abnormality. Alternatively, if at least two of the first, second, and third test results indicate that the battery cell has an infiltration abnormality, the infiltration detection result of the battery cell is determined to be an abnormality.

[0078] In the above embodiment, a first detection result is determined based on the target open-circuit voltage and a preset open-circuit voltage; a second detection result is determined based on the target film-forming voltage and a preset film-forming voltage; a third detection result is determined based on the voltage difference between the target open-circuit voltage and the target film-forming voltage; and a cell wetness detection result is determined based on the first, second, and third detection results. In the technical solution of the embodiment of the present application, utilizing multiple detection results for detection can improve detection accuracy and reduce the risk of over- and under-detection.

[0079] According to some embodiments of the present application, the charging process data includes the charging capacity and charging voltage at multiple charging moments, referring to Figure 7 In the above embodiment, “determining the target film-forming voltage of the solid electrolyte interface film in the battery cell according to the charging process data” may include the following steps:

[0080] Step 501 : determining a charging capacity difference and a charging voltage difference between every two adjacent charging moments based on the charging capacity and charging voltage at multiple charging moments.

[0081] For the acquired charging process data, the difference between the charging capacity at time t2 and the charging capacity at time t1 is calculated to obtain multiple charging capacity difference values; the difference between the charging voltage at time t2 and the charging voltage at time t1 is calculated to obtain multiple charging voltage difference values, where t2 = t1 + 1.

[0082] Step 502 : determining a differential capacitance curve according to a plurality of charging capacity differences and charging voltage differences.

[0083] Calculate the ratio of each charge capacity difference to the charge voltage difference at the corresponding moment, and determine the differential capacitance curve based on the ratio and the charge voltage, referring to formula (1) and Figure 8 In the figure, the horizontal axis is the charging voltage, in volts (V), and the vertical axis is the ratio of the charging capacity difference to the charging voltage difference at the corresponding moment.

[0084] -----------------------------------(1)

[0085] Where Q is the charge capacity and V is the charge voltage.

[0086] Step 503 : extracting a peak voltage from a preset voltage interval of the differential capacitance curve, and determining the peak voltage as a target film-forming voltage of the solid electrolyte interface film in the battery cell.

[0087] The film forming voltage is usually between 2.0V and 2.8V, so 2.0V to 2.8V is determined as the preset voltage interval.

[0088] The computer device can use simulation software or a preset algorithm to extract the peak voltage between 2.0V and 2.8V from the differential capacitance curve and determine the peak voltage as the target SEI film formation voltage. It can be understood that using the computer device to calculate the charge capacity difference and the charge voltage difference, determine the differential capacitance curve based on the charge capacity difference and the charge voltage difference, and extract the peak voltage from the differential capacitance curve not only allows for batch voltage testing, but also improves detection efficiency compared to manual testing.

[0089] In the above embodiment, the charge capacity difference and charge voltage difference between each two adjacent charge moments are determined based on the charge capacity and charge voltage at multiple charge moments; a differential capacitance curve is determined based on the multiple charge capacity differences and charge voltage differences; the peak voltage is extracted from the preset voltage range of the differential capacitance curve, and the peak voltage is determined as the target film-forming voltage of the solid electrolyte interface film in the battery cell. In the technical solution of the embodiment of the present application, the differential capacitance curve is determined based on the charge capacity and charge voltage, and a relatively accurate target film-forming voltage can be extracted, providing an accurate basis for detecting the infiltration effect, thereby improving the accuracy of battery cell detection.

[0090] According to some embodiments of the present application, referring to Figure 9 In the above embodiment, “obtaining charging process data of a battery cell according to a preset charging process” may include the following steps:

[0091] Step 601: Control the charging device to perform constant current charging on the battery cell according to a preset charging rate and a preset charging time.

[0092] The preset charging time is determined by the preset state of charge (SOC) and the preset charge rate. For example, if the preset SOC is 0.01% and the preset charge rate is 0.05C, the preset charging time T = 1 / 0.05C * 0.01% * 60 = 12 (min).

[0093] It should be noted that the lower the charge rate, the less impact the polarization reaction inside the cell has on the SEI film formation potential during charging. Considering the charging time, the charge rate can be set below 0.1C. Optionally, the preset charge rate is 0.05C.

[0094] After the charging device is connected to the battery cell, the computer device sends a control instruction to the charging device, which carries a preset charging rate and a preset charging time. The charging device receives the control instruction and charges the battery cell with a constant current according to the control instruction.

[0095] Alternatively, the computer device sends control information to the charging device for storage in advance, the control information including a preset charging rate and a preset charging time. After the charging device is connected to the battery cell, the battery cell is charged with a constant current according to the pre-stored control information.

[0096] For example, the charging device uses a constant current of 0.05C to charge the battery cell for 12 minutes.

[0097] In some embodiments, after the charging device performs constant current charging on the battery cell according to a preset charging rate and a preset charging time, the computer device controls the charging device to form the battery cell. The formation process may include: standing still for 30 seconds, and charging the battery cell with a constant current at a charging rate of 0.1C until the state of charge of the battery cell reaches 0.3% or higher. It should be noted that the standing time, charging rate, state of charge at the end of charging, and charging time in the formation process can all be set according to actual conditions.

[0098] Step 602: Acquire charging process data collected by the charging device during the charging process.

[0099] During the charging process, the charging device collects charging capacity and charging voltage at multiple times to obtain charging process data. The charging device can send this charging process data to the computer in real time during the collection process, or it can send all charging process data to the computer after the battery cell is fully charged. Alternatively, the charging device can store the charging process data after data collection, and the computer can derive the charging process data from the charging device when determining the battery cell infiltration detection results.

[0100] It should be noted that the manner in which the computer device obtains the charging process data from the charging device is not limited to the above example and can be set according to actual conditions.

[0101] In the above-mentioned embodiment, the charging device is controlled to charge the battery cell with a constant current according to a preset charge rate and a preset charge duration; and charging process data collected by the charging device during the charging process is obtained. In the technical solution of the embodiment of the present application, the constant current charging of the battery cell according to the preset charge rate and a preset charge duration can minimize the impact of the polarization reaction on the film-forming voltage, thereby making the film-forming voltage more stable and thereby improving the accuracy of the infiltration detection.

[0102] According to some embodiments of the present application, referring to Figure 10 In the above embodiment, “obtaining the target open circuit voltage of the battery cell after the soaking process” includes:

[0103] Step 701 , obtaining a plurality of original open circuit voltages obtained by performing open circuit voltage detection on the battery cell after the soaking process, each time the battery cell is left to stand for a preset time.

[0104] After the high-temperature soaking process, let the cell rest. Then, test the open circuit voltage of the cell every 10 seconds to obtain an original open circuit voltage. Perform three tests to obtain three original open circuit voltages.

[0105] It should be noted that the preset time length can be 20 seconds or longer, and the number of detections can be 3-10 times or more. In actual applications, the preset time length and number of detections can be determined by comprehensively considering test accuracy and test efficiency.

[0106] Step 702 : determining a target open circuit voltage according to a plurality of original open circuit voltages.

[0107] After obtaining multiple original open circuit voltages, the minimum open circuit voltage among the multiple original open circuit voltages may be determined as the target open circuit voltage; or the maximum open circuit voltage among the multiple original open circuit voltages may be determined as the target open circuit voltage.

[0108] In the above embodiment, multiple raw open-circuit voltages are obtained by testing the cell after the soaking process, after each cell is left to rest for a preset period of time. A target open-circuit voltage is determined based on these multiple raw open-circuit voltages. In the technical solution of the present embodiment, multiple open-circuit voltage tests can reduce test errors, improve the accuracy of the target open-circuit voltage, and thus improve the accuracy of soaking detection.

[0109] According to some embodiments of the present application, "determining the target open circuit voltage based on multiple original open circuit voltages" in the above embodiment may include: calculating the average open circuit voltage of the multiple original open circuit voltages, and determining the average open circuit voltage as the target open circuit voltage.

[0110] For example, the open circuit voltage of the battery cell is tested once every 10 seconds to obtain an original open circuit voltage. The three tests are performed three times to obtain three original open circuit voltages V1, V2, and V3. The average value of V1, V2, and V3 is calculated. OCV , V OCV Determine the target open circuit voltage.

[0111] In the above embodiment, the average open-circuit voltage of multiple raw open-circuit voltages is calculated and the average open-circuit voltage is determined as the target open-circuit voltage. In the technical solution of the embodiment of the present application, the average voltage value is used as the target open-circuit voltage, which can reduce test errors, improve the accuracy of the target open-circuit voltage, and thus improve the accuracy of infiltration detection.

[0112] According to some embodiments of the present application, a battery cell detection method is provided, which is applied to Figure 1 Taking the computer device in the example as an example, the following steps may be included:

[0113] Step 1: obtaining a plurality of original open circuit voltages obtained by performing open circuit voltage detection on the battery cell after the soaking process by standing for a preset time.

[0114] Step 2: Calculate an average open circuit voltage of the multiple original open circuit voltages and determine the average open circuit voltage as the target open circuit voltage.

[0115] Step 3: Control the charging device to perform constant current charging on the battery cell according to a preset charging rate and a preset charging time.

[0116] The preset charging time is determined based on the preset state of charge and the preset charging rate.

[0117] Step 4: Obtain charging process data collected by the charging device during the charging process.

[0118] The charging process data includes the charging capacity and charging voltage at multiple charging moments.

[0119] Step 5: Determine the charging capacity difference and charging voltage difference between every two adjacent charging moments based on the charging capacity and charging voltage at multiple charging moments.

[0120] Step 6: Determine a differential capacitance curve based on the multiple charging capacity differences and charging voltage differences.

[0121] Step 7: extract the peak voltage from the preset voltage range of the differential capacitance curve, and determine the peak voltage as the target film-forming voltage of the solid electrolyte interface film in the battery cell.

[0122] Step 8: Calculate the voltage difference between the target open circuit voltage and the target film forming voltage.

[0123] Step 9: If the voltage difference exceeds the preset voltage range, the cell infiltration detection result is determined to be abnormal cell infiltration; wherein the preset voltage range is obtained by pre-statistically analyzing the voltage differences corresponding to multiple test samples.

[0124] In the above embodiment, multiple detections of the open circuit voltage can reduce the test error and improve the accuracy of the target open circuit voltage; constant current charging of the battery cell according to a preset charging rate and a preset charging time can minimize the influence of the polarization reaction on the film-forming voltage, thereby making the film-forming voltage more stable; determining the differential capacitance curve according to the charging capacity and the charging voltage can extract a more accurate target film-forming voltage; using the voltage difference to determine whether the battery cell has an infiltration anomaly is more accurate than using the target open circuit voltage or the target film-forming voltage alone for detection. In the technical solution of the embodiment of the present application, the battery cell is determined to have an infiltration anomaly based on the open circuit voltage and the film-forming voltage, and the battery cell detection can be carried out in batches. Not only is the detection efficiency high and the risk of missing is reduced, but there is no need to disassemble the battery cell, thereby reducing various costs of detection investment.

[0125] It should be understood that, although the various steps in the above flow chart are shown in sequence as indicated by the arrows, these steps are not necessarily performed in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and these steps can be performed in other orders. Moreover, at least a portion of the steps in the above flow chart may include multiple steps or multiple stages, and these steps or stages are not necessarily performed at the same time, but can be performed at different times. The execution order of these steps or stages is not necessarily to be performed in sequence, but can be performed in turn or alternately with other steps or at least a portion of steps or stages in other steps.

[0126] Based on the same inventive concept, the present application also provides a cell detection device for implementing the cell detection method mentioned above. The solution provided by this device is similar to the solution described in the above method. Therefore, the specific limitations of one or more cell detection device embodiments provided below can be found in the above limitations of the cell detection method and will not be repeated here.

[0127] According to some embodiments of the present application, referring to Figure 11 , provides a battery cell detection device, the device comprising:

[0128] The open circuit voltage acquisition module 801 is used to obtain the target open circuit voltage of the battery cell after the soaking process;

[0129] The film formation voltage acquisition module 802 is used to obtain charging process data of the battery cell according to a preset charging process, and determine the target film formation voltage of the solid electrolyte interface film in the battery cell based on the charging process data;

[0130] The wetting detection module 803 is used to determine the wetting detection result of the battery cell according to the target open circuit voltage and the target film forming voltage; the wetting detection result is used to indicate whether there is wetting abnormality in the battery cell.

[0131] In some embodiments, the infiltration detection module 803 is specifically used to calculate the voltage difference between the target open circuit voltage and the target film forming voltage; if the voltage difference exceeds the preset voltage range, the infiltration detection result of the battery cell is determined to be that there is an infiltration abnormality in the battery cell; wherein the preset voltage range is obtained by pre-statistical analysis of the voltage differences corresponding to multiple test samples.

[0132] In some embodiments, the infiltration detection module 803 is specifically used to determine a first detection result based on a target open circuit voltage and a preset open circuit voltage; determine a second detection result based on a target film forming voltage and a preset film forming voltage; determine a third detection result based on a voltage difference between the target open circuit voltage and the target film forming voltage; and determine the infiltration detection result of the battery cell based on the first detection result, the second detection result, and the third detection result.

[0133] In some embodiments, the charging process data includes the charging capacity and charging voltage at multiple charging moments, and the film-forming voltage acquisition module 802 is specifically used to determine the charging capacity difference and charging voltage difference between each two adjacent charging moments based on the charging capacity and charging voltage at multiple charging moments; determine the differential capacitance curve based on the multiple charging capacity differences and charging voltage differences; extract the peak voltage from the preset voltage range of the differential capacitance curve, and determine the peak voltage as the target film-forming voltage of the solid electrolyte interface film in the battery cell.

[0134] In some embodiments, the film forming voltage acquisition module 802 is specifically used to control the charging device to perform constant current charging on the battery cell according to a preset charging rate and a preset charging time; wherein the preset charging time is determined based on a preset state of charge and a preset charging rate; and obtain charging process data collected by the charging device during the charging process.

[0135] In some embodiments, the open circuit voltage acquisition module 801 is specifically used to obtain multiple original open circuit voltages obtained by performing open circuit voltage detection on the battery cell after the soaking process, each time the battery cell is left to stand for a preset time; and determine the target open circuit voltage based on the multiple original open circuit voltages.

[0136] In some embodiments, the open circuit voltage acquisition module 801 is specifically configured to calculate an average open circuit voltage of a plurality of original open circuit voltages, and determine the average open circuit voltage as the target open circuit voltage.

[0137] Each module in the above-mentioned battery cell detection device can be implemented in whole or in part through software, hardware, or a combination thereof. Each of the above-mentioned modules can be embedded in or independent of the processor of the electronic device in hardware form, or can be stored in the memory of the electronic device in software form, so that the processor can call and execute the corresponding operations of each of the above modules.

[0138] According to some embodiments of the present application, a computer device is provided. The computer device may be a terminal, and its internal structure diagram may be as follows: Figure 12 As shown. The computer device includes a processor, memory, an input / output interface, a communication interface, a display unit, and an input device. The processor, memory, and input / output interface are connected via a system bus, and the communication interface, display unit, and input device are connected to the system bus via the input / output interface. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores an operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage medium. The input / output interface of the computer device is used to exchange information between the processor and external devices. The communication interface of the computer device is used to communicate with external terminals via wired or wireless means, and the wireless means can be achieved via Wi-Fi, mobile cellular networks, NFC (near-field communication), or other technologies. When executed by the processor, the computer program implements a battery cell detection method. The display unit of the computer device is used to form a visually visible image, and can be a display screen, a projection device, or a virtual reality imaging device. The display screen can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covering the display screen, or a button, trackball or touchpad set on the computer device casing, or an external keyboard, touchpad or mouse.

[0139] Those skilled in the art will understand that Figure 12 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than shown in the figure, or combine certain components, or have a different component arrangement.

[0140] According to some embodiments of the present application, a non-transitory computer-readable storage medium including instructions is also provided, such as a memory including instructions. The instructions can be executed by a processor of an electronic device to perform the above method. For example, the non-transitory computer-readable storage medium can be a ROM, a random access memory (RAM), a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, etc.

[0141] According to some embodiments of the present application, a computer program product is also provided. When executed by a processor, the computer program can implement the above-mentioned method. The computer program product includes one or more computer instructions. When these computer instructions are loaded and executed on a computer, part or all of the above-mentioned method can be implemented in whole or in part according to the processes or functions described in the embodiments of the present application.

[0142] Those skilled in the art will appreciate that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the above-mentioned embodiments. In particular, any reference to memory, database, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The databases involved in the various embodiments provided herein may include at least one of a relational database and a non-relational database. Non-relational databases may include, but are not limited to, distributed databases based on blockchains. The processors involved in the various embodiments provided herein may be, but are not limited to, general-purpose processors, central processing units (CPUs), graphics processing units (GPUs), digital signal processors (DSPs), programmable logic devices (PLDs), data processing logic devices based on quantum computing, and the like.

[0143] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0144] The embodiments described above only express several implementation methods of the present application, which are convenient for understanding the technical solutions of the present application in a specific and detailed manner, but they cannot be understood as limiting the scope of protection of the invention patent. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present application, several variations and improvements can be made, which all fall within the scope of protection of the present application. It should be understood that the technical solutions obtained by those skilled in the art through logical analysis, reasoning or limited experiments on the basis of the technical solutions provided in the present application are all within the scope of protection of the attached claims described in the present application. Therefore, the scope of protection of the patent of this application shall be based on the content of the attached claims, and the description and drawings can be used to interpret the content of the claims.

Claims

1. A battery cell detection method, characterized in that: The method comprises: Obtain the target open circuit voltage of the battery cell after the soaking process; Acquiring charging process data of the battery cell according to a preset charging process, and determining a target film-forming voltage of a solid electrolyte interface film in the battery cell according to the charging process data; Determining a wetting detection result of the battery cell according to the target open circuit voltage and the target film forming voltage; the wetting detection result is used to characterize whether there is wetting abnormality in the battery cell; Wherein, determining the wetting detection result of the battery cell according to the target open circuit voltage and the target film forming voltage includes: Calculating a voltage difference between the target open circuit voltage and the target film forming voltage; If the voltage difference exceeds a preset voltage range, it is determined that the wetting detection result of the battery cell is that the battery cell has abnormal wetting; wherein the preset voltage range is obtained by pre-statistically analyzing the voltage difference values ​​corresponding to a plurality of test samples.

2. The method according to claim 1, characterized in that The step of determining the wetting detection result of the battery cell according to the target open circuit voltage and the target film forming voltage includes: Determine a first detection result according to the target open circuit voltage and a preset open circuit voltage; Determine a second detection result according to the target film forming voltage and the preset film forming voltage; determining a third detection result according to a voltage difference between the target open circuit voltage and the target film forming voltage; The infiltration detection result of the battery cell is determined according to the first detection result, the second detection result and the third detection result.

3. The method according to claim 1, characterized in that The charging process data includes charging capacity and charging voltage at multiple charging moments, and determining a target film-forming voltage of a solid electrolyte interface film in the battery cell according to the charging process data includes: Determining a charging capacity difference and a charging voltage difference between every two adjacent charging moments according to the charging capacities and charging voltages at the plurality of charging moments; Determining a differential capacitance curve according to a plurality of the charging capacity differences and the charging voltage differences; A peak voltage is extracted from a preset voltage interval of the differential capacitance curve, and the peak voltage is determined as a target film-forming voltage of a solid electrolyte interface film in the battery cell.

4. The method according to any one of claims 1 to 3, characterized in that: The obtaining of charging process data of the battery cell according to a preset charging process includes: Controlling the charging device to perform constant current charging on the battery cell according to a preset charging rate and a preset charging duration; wherein the preset charging duration is determined according to a preset state of charge and the preset charging rate; Acquire the charging process data collected by the charging device during the charging process.

5. The method according to any one of claims 1 to 3, characterized in that: The step of obtaining the target open circuit voltage of the battery cell after the wetting process includes: Acquire multiple original open circuit voltages of the battery cell after the infiltration process, obtained by performing open circuit voltage detection after the battery cell is left to stand for a preset time; The target open circuit voltage is determined according to a plurality of the original open circuit voltages.

6. The method according to claim 5, characterized in that The step of determining the target open circuit voltage according to the plurality of original open circuit voltages comprises: An average open circuit voltage of the plurality of original open circuit voltages is calculated, and the average open circuit voltage is determined as the target open circuit voltage.

7. A battery cell detection device, characterized in that: The device comprises: An open circuit voltage acquisition module is used to obtain the target open circuit voltage of the battery cell after the soaking process; A film-forming voltage acquisition module, used to acquire charging process data of the battery cell according to a preset charging process, and determine a target film-forming voltage of the solid electrolyte interface film in the battery cell according to the charging process data; A wetting detection module, used to determine a wetting detection result of the battery cell according to the target open circuit voltage and the target film forming voltage; the wetting detection result is used to characterize whether there is wetting abnormality in the battery cell; Among them, the wetting detection module is used to calculate the voltage difference between the target open circuit voltage and the target film forming voltage; if the voltage difference exceeds the preset voltage range, the wetting detection result of the battery cell is determined to be that the battery cell has wetting abnormality; wherein, the preset voltage range is obtained by pre-statisticing the voltage difference values ​​corresponding to multiple test samples.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the method according to any one of claims 1 to 6 is implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 1 to 6 is implemented.

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