Missing coating defect detection method and apparatus for electrode sheet, electronic device, and storage medium

Abstract

The present application discloses a missing coating defect detection method and apparatus for an electrode sheet, an electronic device, and a storage medium. The missing coating defect detection method for an electrode sheet comprises: determining the current charging voltage plateau and the current differential capacity peak value of a battery cell on the basis of a target differential capacity curve; determining a charging voltage plateau offset of the battery cell on the basis of a standard charging voltage plateau and the current charging voltage plateau of the battery cell; determining a differential capacity peak value change rate of the battery cell on the basis of the current differential capacity peak value and a standard differential capacity peak value; on the basis of a capacity fade curve, determining capacity fade rate offsets corresponding to the first n charge-discharge cycles among N charge-discharge cycles; and when the charging voltage plateau offset is greater than or equal to a charging voltage plateau offset threshold, the differential capacity peak value change rate is greater than or equal to a differential capacity peak value change rate threshold, and the capacity fade rate offsets corresponding to the first n charge-discharge cycles are all greater than a capacity fade rate offset threshold, determining that an anode sheet missing coating defect is present in the battery cell.

Description

Method and device for detecting coating defect of pole piece, electronic equipment and storage medium

[0001] Cross-reference to related applications

[0002] This application is based on Chinese Patent Application No. 202411128009.0 entitled "Method and device for detecting coating defect of pole piece, electronic equipment and storage medium" filed on August 16, 2024, which is incorporated by reference in its entirety into this application. TECHNICAL FIELD

[0003] The present application belongs to the technical field of batteries, and particularly relates to a method and device for detecting coating defect of pole piece, electronic equipment and storage medium. BACKGROUND

[0004] With the development of technology, lithium batteries as a kind of energy device are increasingly attracting people's attention. The electrode is an important component of the battery cell of the lithium battery. In the preparation process of the lithium battery, the preparation of the electrode is crucial. Generally, the preparation of the electrode includes steps such as slurry mixing, coating, drying, rolling and cutting, among which the coating step is particularly important.

[0005] In the coating process of lithium battery production, the coating head is prone to blockage, and the electrode pole piece of the battery cell is prone to coating defects, such as anode pole piece coating defects. Therefore, it is necessary to detect the anode pole piece coating defects of the battery cell.

[0006] At present, the optical detection method is mainly used to detect the anode pole piece coating defects of the battery cell. However, in the case that the optical imaging image quality of the anode pole piece is poor, the defective anode pole piece with anode pole piece coating defects is easily misjudged as a normal anode pole piece, resulting in low detection accuracy of the anode pole piece coating defects of the battery cell. SUMMARY

[0007] Therefore, the embodiments of the present application provide a method and device for detecting coating defect of pole piece, electronic equipment and storage medium to overcome the above problems of related technologies.

[0008] In a first aspect, the embodiments of the present application provide a method for detecting coating defect of pole piece, comprising:

[0009] determining a target differential capacity curve and a capacity attenuation curve of the battery cell;

[0010] determining a current charging voltage platform and a current differential capacity peak value of the battery cell according to the target differential capacity curve;

[0011] determining a charging voltage platform offset of the battery cell according to the standard charging voltage platform and the current charging voltage platform of the battery cell;

[0012] determine the differential capacity peak change rate of the battery cell according to the current differential capacity peak of the battery cell relative to the standard differential capacity peak;

[0013] determine a current capacity attenuation rate corresponding to the n times of cycle charging and discharging according to the capacity attenuation curve, N / 300≤n≤N / 140, N and n are integers, and n is greater than 1;

[0014] determine a capacity attenuation rate offset corresponding to the n times of cycle charging and discharging according to the standard capacity attenuation rate and the current capacity attenuation rate of the battery cell;

[0015] determine that the battery cell has anode tab coating defect in a case where the charging voltage platform offset is greater than or equal to the charging voltage platform offset threshold, the differential capacity peak change rate is greater than or equal to the differential capacity peak change rate threshold, and the capacity attenuation rate offset corresponding to the n times of cycle charging and discharging is all greater than the capacity attenuation rate offset threshold.

[0016] The scheme provided in the application is that, in the charging process of the battery cell, in a case where the anode tab has coating defect, the copper is exposed at the coating defect of the anode tab, the lithium ion is oxidized and reduced at the exposed copper, the anode potential of the anode tab with coating defect is smaller than that of the anode tab without coating defect, the charging voltage platform, the differential capacity peak, and the capacity attenuation rate corresponding to the n times of cycle charging and discharging of the battery cell are greatly offset, and therefore, the charging voltage platform offset, the differential capacity peak change rate, and the capacity attenuation rate offset corresponding to the n times of cycle charging and discharging of the battery cell are used to detect the coating defect of the anode tab of the battery cell, which is beneficial to improve the detection accuracy of the coating defect of the anode tab of the battery cell.

[0017] In some optional embodiments, determining the current charging voltage platform according to the target differential capacity curve includes:

[0018] determining the differential capacity peak according to the target differential capacity curve;

[0019] determining the current charging voltage platform as the battery cell voltage corresponding to the differential capacity peak.

[0020] The scheme provided in the embodiment improves the accuracy of the current charging voltage platform.

[0021] In some optional embodiments, determining the target differential capacity curve of the battery cell includes:

[0022] determining a plurality of differential capacities of the battery cell at a plurality of target battery cell voltages, each target battery cell voltage corresponding to a differential capacity;

[0023] According to the plurality of differential capacities and the plurality of target cell voltages, a target differential capacity curve is constructed.

[0024] The scheme provided by the embodiment is based on each target cell voltage and a differential capacity corresponding to each target cell voltage, and the target differential capacity curve is constructed, which is beneficial to improve the construction accuracy of the target differential capacity curve.

[0025] In some optional embodiments, determining the plurality of differential capacities of the cell under the plurality of target cell voltages comprises:

[0026] A plurality of groups of charging parameters of the cell are collected at preset time intervals, and each group of charging parameters comprises a charging current, an initial cell voltage and a target cell voltage;

[0027] According to each group of charging parameters, a differential capacity of the cell under a target cell voltage is determined to obtain the plurality of differential capacities.

[0028] The scheme provided by the embodiment is based on each group of charging parameters of the cell collected in the charging process, and a differential capacity of the cell under a target cell voltage is calculated, which is beneficial to improve the calculation accuracy of the differential capacity.

[0029] In some optional embodiments, according to each group of charging parameters, a differential capacity of the cell under a target cell voltage is determined, comprising:

[0030] According to an initial cell voltage and a target cell voltage of each group of charging parameters, a cell voltage change amount is determined;

[0031] According to a charging current and a preset time interval of each group of charging parameters, a cell capacity change amount is determined;

[0032] According to a cell voltage change amount and a cell capacity change amount corresponding to each group of charging parameters, a differential capacity of the cell under a target cell voltage of each group of charging parameters is calculated.

[0033] In some optional embodiments, the tab undercoating defect detection method further comprises:

[0034] In a case where the charging voltage platform offset is less than the charging voltage platform offset threshold, and / or the differential capacity peak change rate is less than the differential capacity peak change rate threshold, and / or the capacity attenuation rate offset corresponding to at least one of the n cycle charging and discharging is less than or equal to the capacity attenuation rate offset threshold, it is determined that the cell does not have an anode tab undercoating defect.

[0035] The scheme provided by the embodiment is based on the charging voltage platform offset to determine whether the anode pole piece of the battery cell has a coating defect, and is beneficial to improving the determination accuracy of the coating defect of the anode pole piece of the battery cell.

[0036] In a second aspect, the embodiment of the present application provides a pole piece coating defect detection device, comprising:

[0037] A first determination module is configured to determine a target differential capacity curve of the battery cell, and determine a current charging voltage platform and a current differential capacity peak value of the battery cell according to the target differential capacity curve.

[0038] A second determination module is configured to determine a charging voltage platform offset of the battery cell according to a standard charging voltage platform and the current charging voltage platform of the battery cell.

[0039] A fourth determination module is configured to determine a differential capacity peak value change rate of the battery cell according to a change rate of the current differential capacity peak value of the battery cell relative to a standard differential capacity peak value.

[0040] A fifth determination module is configured to determine a capacity attenuation curve of the battery cell, and determine a current capacity attenuation rate corresponding to the n-th cycle of the N cycles of charging and discharging according to the capacity attenuation curve, N / 300≤n≤N / 140, N and n are integers, and n is greater than 1.

[0041] A sixth determination module is configured to determine a capacity attenuation rate offset corresponding to the n-th cycle of the N cycles of charging and discharging according to a standard capacity attenuation rate and a current capacity attenuation rate of the battery cell.

[0042] A third determination module is configured to determine that the battery cell has an anode pole piece coating defect when the charging voltage platform offset is greater than or equal to a charging voltage platform offset threshold, the differential capacity peak value change rate is greater than or equal to a differential capacity peak value change rate threshold, and the capacity attenuation rate offset corresponding to the n-th cycle of the N cycles of charging and discharging is greater than a capacity attenuation rate offset threshold.

[0043] In a third aspect, the embodiment of the present application provides an electronic device, comprising:

[0044] A memory;

[0045] One or more processors coupled to the memory;

[0046] One or more application programs, wherein the one or more application programs are stored in the memory and configured to be executed by the one or more processors, and the one or more application programs are configured to execute the pole piece coating defect detection method provided in the first aspect.

[0047] In a fourth aspect, an embodiment of the present application provides a computer readable storage medium, and the computer readable storage medium stores program codes. The program codes can be invoked by a processor to execute the pole piece missing coating defect detection method provided in the first aspect.

[0048] In a fifth aspect, an embodiment of the present application provides a computer program product. When the computer program product runs on a computer device, the computer program product causes the computer device to execute the pole piece missing coating defect detection method provided in the first aspect.

[0049] It can be understood that the beneficial effects of the second aspect to the fifth aspect can be referred to the related description in the first aspect, and will not be repeated here. BRIEF DESCRIPTION OF DRAWINGS

[0050] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments or exemplary technical description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0051] FIG. 1 shows a flowchart of the pole piece missing coating defect detection method provided by an embodiment of the present application.

[0052] FIG. 2 shows a scenario diagram of the initial differential capacity curve of different battery cells in the pole piece missing coating defect detection method shown in FIG. 1.

[0053] FIG. 3 shows a scenario diagram of the target differential capacity curve of different battery cells in the pole piece missing coating defect detection method shown in FIG. 1.

[0054] FIG. 4 shows a scenario diagram of the capacity attenuation curve of different battery cells in the pole piece missing coating defect detection method shown in FIG. 1.

[0055] FIG. 5 shows another flowchart of the pole piece missing coating defect detection method provided by an embodiment of the present application.

[0056] FIG. 6 shows a structure block diagram of the pole piece missing coating defect detection device provided by an embodiment of the present application.

[0057] FIG. 7 shows a function block diagram of the electronic device provided by an embodiment of the present application.

[0058] FIG. 8 shows a computer readable storage medium provided by an embodiment of the present application, which is used to save or carry the program codes for implementing the pole piece missing coating defect detection method provided by an embodiment of the present application.

[0059] FIG. 9 shows a computer program product for storing or carrying program code for implementing the method for detecting the pole piece missing coating defect according to the embodiments of the present application. DETAILED DESCRIPTION

[0060] In order to make the objectives, characteristics and advantages of the present application more apparent and easy to understand, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the embodiments described below 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 of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0061] It should be understood that, when used in the specification and the appended claims, the term "comprising" indicates the presence of the described 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.

[0062] It should also be understood that the terms used in the present application specification are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in the present application specification and the appended claims, unless otherwise clearly indicated by the context, the singular forms "a", "an" and "the" are intended to include the plural forms as well.

[0063] It should be further understood that the term "and / or" used in the present application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations thereof.

[0064] In addition, in the description of the present application, the terms "first", "second", "third" and the like are only used to distinguish description and cannot be understood as indicating or implying relative importance.

[0065] With the development of science and technology, lithium batteries as a kind of energy device are more and more concerned by people. The electrode is an important component of the battery cell of the lithium battery, and the preparation of the electrode is crucial in the preparation process of the lithium battery. Generally, the preparation of the electrode includes slurry mixing, coating, drying, rolling and cutting steps, among which the coating step is particularly important.

[0066] In the coating process of lithium battery production, the electrode pole piece of the battery cell is coated by a coating head, which is a cylindrical extrusion head. The coating head coats the electrode pole piece by being extruded. The coating head is prone to blockage during extrusion, and the electrode pole piece is prone to missing coating, such as missing coating of the anode pole piece. Therefore, the anode pole piece missing coating defect detection of the battery cell is needed.

[0067] Currently, the anode tab coating defect detection of the battery cell mainly relies on optical detection methods. However, in the case that the optical imaging image quality of the anode tab is poor, the defect anode tab with the anode tab coating defect is easily misjudged as a normal anode tab, which leads to low detection accuracy of the anode tab coating defect detection of the battery cell.

[0068] To solve the above problems, the anode tab coating defect detection method, the detection device, the electronic equipment and the storage medium provided by the embodiments of the present application determine the current charging voltage platform and the current differential capacity peak value of the battery cell, determine the charging voltage platform offset of the battery cell according to the standard charging voltage platform and the current charging voltage platform of the battery cell, determine the differential capacity peak value change rate of the battery cell according to the standard differential capacity peak value and the current differential capacity peak value of the battery cell, and determine the current capacity attenuation rate corresponding to the n th cycle of the N cycles of charging and discharging according to the capacity attenuation curve of the battery cell, N / 300≤n≤N / 140, N and n are integers, and n is greater than 1. According to the standard capacity attenuation rate and the current capacity attenuation rate of the battery cell, the capacity attenuation rate offset corresponding to the n th cycle of the N cycles of charging and discharging is determined. In the case that the charging voltage platform offset is greater than or equal to the charging voltage platform offset threshold, the differential capacity peak value change rate is greater than or equal to the differential capacity peak value change rate threshold, and the capacity attenuation rate offset corresponding to the n th cycle of the N cycles of charging and discharging is greater than the capacity attenuation rate offset threshold, it is determined that the battery cell has an anode tab coating defect. In the case that the anode tab has a coating defect during the charging process of the battery cell, the copper is exposed at the coating defect of the anode tab, and the lithium ion undergoes oxidation and reduction reaction at the exposed copper. Compared with the anode tab without coating defect, the anode potential of the anode tab is smaller, and the charging voltage platform, the differential capacity peak value and the capacity attenuation rate corresponding to the n th cycle of the N cycles of charging and discharging of the battery cell are greatly offset. Therefore, the anode tab coating defect detection of the battery cell is based on the charging voltage platform offset, the differential capacity peak value change rate and the capacity attenuation rate offset corresponding to the n th cycle of the N cycles of charging and discharging, which is beneficial to improve the detection accuracy of the anode tab coating defect detection of the battery cell.

[0069] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application.

[0070] The anode tab coating defect detection method provided by the embodiments of the present application can be applied to a processing device, which can include but is not limited to any one of a server or a terminal device and the like.

[0071] The server can include but is not limited to a stand-alone physical server, a server cluster composed of multiple physical servers or a distributed system, a cloud server and the like.

[0072] The terminal device can include, but is not limited to, a mobile terminal device (for example, a mobile phone, a personal digital assistant (PDA), a tablet personal computer (Tablet PC), a notebook computer, a smart watch, a smart bracelet, etc.) and a fixed terminal device (for example, a desktop computer, a smart panel, an all-in-one computer, etc.), etc.

[0073] Please refer to FIG. 1, which shows a flowchart of a pole piece missing coating defect detection method provided by an embodiment of the present application. In specific embodiments, the pole piece missing coating defect detection method can be applied to a processing device. In the following, the flowchart shown in FIG. 1 will be described in detail by taking the processing device as an example. The pole piece missing coating defect detection method can include the following steps 110 to 170.

[0074] Step 110: Determine the target differential capacity curve and the capacity attenuation curve of the battery cell.

[0075] Step 120: Determine the current charging voltage platform and the current differential capacity peak value of the battery cell according to the target differential capacity curve.

[0076] In the embodiments of the present application, in the case where a user needs to detect the anode pole piece missing coating defect of the battery cell, a detection instruction can be sent to the processing device. The processing device receives and responds to the detection instruction to determine the current charging voltage platform and the current differential capacity peak value of the battery cell.

[0077] The battery is a lithium battery, which is composed of one or more battery cells, a battery management system (BMS), a protection circuit, a shell and other components.

[0078] The battery cell is the core component of the lithium battery and is responsible for storing electricity. The battery cell usually refers to a single electrochemical cell containing an anode and a cathode. The battery cell includes basic components such as anode material, cathode material, electrolyte and separator.

[0079] The BMS is mainly responsible for monitoring and managing the charging and discharging process of the battery cell to ensure the safety and efficient operation of the battery.

[0080] The charging voltage platform can be used to represent the battery cell voltage corresponding to the maximum differential capacity of the battery cell during the charging process.

[0081] The differential capacity refers to the change rate of the charge storage capacity of the battery cell of the lithium battery at a certain potential, which is represented by dQ / dV. dQ represents the capacity change amount of the battery cell at the potential, and dV represents the battery cell voltage change amount of the battery cell at the potential.

[0082] Exemplarily, in a case that the user needs to detect the anode tab missing defect of the battery cell, a detection instruction can be sent to the processing device, the processing device receives and responds to the detection instruction, determines a target differential capacity curve of the battery cell, and determines a current charging voltage platform according to the target differential capacity curve. The target differential capacity curve can be used to represent the correspondence between the battery cell voltage and the differential capacity. The current charging voltage platform is determined based on the target differential capacity curve, which improves the determination accuracy of the current charging voltage platform.

[0083] Regarding the process of determining the target differential capacity curve of the battery cell by the processing device, in some embodiments, the processing device can determine a plurality of differential capacities of the battery cell at a plurality of target battery cell voltages, and construct the target differential capacity curve according to the plurality of differential capacities and the plurality of target battery cell voltages. Each target battery cell voltage can correspond to one differential capacity. The target differential capacity curve is constructed based on each target battery cell voltage and the differential capacity corresponding to each target battery cell voltage, which is conducive to improving the construction accuracy of the target differential capacity curve.

[0084] Regarding the process of determining the plurality of differential capacities of the battery cell at the plurality of target battery cell voltages by the processing device, in some embodiments, the processing device can collect a plurality of sets of charging parameters of the battery cell at a preset time interval, and determine one differential capacity of the battery cell at one target battery cell voltage according to each set of charging parameters to obtain the plurality of differential capacities. One differential capacity of the battery cell at one target battery cell voltage is calculated based on each set of charging parameters collected during the charging process, which is conducive to improving the calculation accuracy of the differential capacity.

[0085] Each set of charging parameters can include but is not limited to one charging current, one initial battery cell voltage, and one target battery cell voltage. The charging current in each set of charging parameters is the average charging current of the preset time interval charging process corresponding to the set of charging parameters. The initial battery cell voltage in each set of charging parameters is the battery cell voltage at the starting charging time of the preset time interval charging process corresponding to the set of charging parameters. The target battery cell voltage in each set of charging parameters is the battery cell voltage at the termination charging time of the preset time interval charging process corresponding to the set of charging parameters.

[0086] Exemplarily, the processing device can be connected to the BMS through a network and communicate with the BMS through the network. The processing device can send a collection instruction to the BMS through the network. The BMS receives and responds to the collection instruction, collects a plurality of sets of charging parameters during the charging process of the battery cell, and sends the plurality of sets of charging parameters to the processing device through the network. The processing device receives the plurality of sets of charging parameters returned by the BMS, and calculates one differential capacity of the battery cell at one target battery cell voltage according to each set of charging parameters to obtain the plurality of differential capacities.

[0087] The network can include, but is not limited to, a ZigBee network, a Bluetooth (BT) network, a Wireless Fidelity (Wi-Fi) network, a Thread network, a Long Range Radio (LoRa) network, a Low-Power Wide-Area Network (LPWAN), an infrared network, a Narrow Band Internet of Things (NB-IoT), a Controller Area Network (CAN), a Digital Living Network Alliance (DLNA) network, a Wide Area Network (WAN), a Local Area Network (LAN), a Metropolitan Area Network (MAN), or a Wireless Personal Area Network (WPAN), etc.

[0088] Regarding the process that the processing device determines a differential capacity of the battery cell at a target battery cell voltage according to each set of charging parameters, in some embodiments, the processing device can determine a battery cell voltage variation according to an initial battery cell voltage and a target battery cell voltage of each set of charging parameters, determine a battery cell capacity variation according to a charging current and a preset time interval of the set of charging parameters, and calculate a differential capacity of the battery cell at a target battery cell voltage of each set of charging parameters according to a battery cell voltage variation and a battery cell capacity variation corresponding to the set of charging parameters.

[0089] Regarding the process that the processing device determines a current charging voltage plateau according to the target differential capacity curve, in some embodiments, the processing device can determine a current differential capacity peak value according to the target differential capacity curve, determine a battery cell voltage corresponding to the current differential capacity peak value as the current charging voltage plateau, and improve the accuracy of the current charging voltage plateau. The current differential capacity peak value represents a maximum battery cell capacity variation corresponding to a unit battery cell voltage, and the current charging voltage plateau is determined according to the battery cell voltage corresponding to the current differential capacity peak value.

[0090] In some embodiments, the processing device can be provided with an input panel, and in the case that the user needs to perform anode tab missing coating defect detection on the battery cell, the detection instruction can be input on the input panel of the processing device, for example, the detection instruction can be handwritten on the input panel, and for example, the detection instruction can be input by pressing the keys on the input panel, and the processing device receives the detection instruction through the input panel.

[0091] In some embodiments, the processing device can be provided with a voice recognition module, and in the case that the user needs to perform anode tab missing coating defect detection on the battery cell, voice information can be sent within the voice collection range of the voice recognition module. The voice recognition module collects the voice information issued by the user, and performs voice recognition on the collected voice information. In the case that the recognition result of the voice recognition contains a keyword indicating that the processing device performs anode tab missing coating defect detection on the battery cell, for example, the keyword is "anode tab missing coating defect detection", and for example, the keyword is "anode tab missing coating defect" and "detection", etc., it is determined that the detection instruction for performing anode tab missing coating defect detection on the battery cell is received.

[0092] As an example, the voice information issued by the user is: performing anode tab missing coating defect detection on the battery cell, and the recognition result of the voice recognition contains the keyword "anode tab missing coating defect detection", and it is determined that the detection instruction for performing anode tab missing coating defect detection on the battery cell is received.

[0093] In some embodiments, in the case that the user needs to perform anode tab missing coating defect detection on the battery cell, the detection instruction can be sent to the user client, the user client receives and responds to the detection instruction, and forwards the detection instruction to the processing device through the network, and the processing device receives the detection instruction forwarded by the user client.

[0094] The user client can be connected to the processing device through the network, and can interact with the processing device through the network. The user client can include, but is not limited to, any one of a mobile client (for example, any one of a mobile phone client, a PDA client, a Tablet PC client, a notebook computer client, a smart watch client, a smart bracelet client, or a wearable client, etc.) or a fixed client (for example, a desktop computer client, a smart panel client, etc.) and the like.

[0095] The capacity attenuation curve of the battery cell is used to represent the capacity attenuation rate of the battery cell varying with the number of cycle charging and discharging. The capacity attenuation rate refers to the proportion of the actual capacity of the battery cell relative to the initial capacity, which can be expressed in %. The initial capacity of the battery cell can be the capacity of the battery cell before cycle charging and discharging. Exemplarily, in the case that the user needs to detect the anode tab missing defect of the battery cell, a detection instruction can be sent to the processing device, and the processing device receives and responds to the detection instruction to determine the capacity attenuation curve of the battery cell.

[0096] In some embodiments, a plurality of capacity attenuation rates of the battery cell at N times of cycle charging and discharging can be determined, and the capacity attenuation curve can be constructed according to the plurality of capacity attenuation rates and the number of cycle charging and discharging. The horizontal coordinate of the capacity attenuation curve is the number of cycle charging and discharging, and the vertical coordinate is the capacity attenuation rate.

[0097] Step 130: determining the charging voltage platform offset of the battery cell according to the standard charging voltage platform of the battery cell and the current charging voltage platform.

[0098] In the embodiments of the present application, the processing device can obtain the standard charging voltage platform of the battery cell, and determine the charging voltage platform offset of the battery cell according to the standard charging voltage platform of the battery cell and the current charging voltage platform.

[0099] The standard charging voltage platform of the battery cell is a charging voltage platform calibrated by the user in advance, and the standard charging voltage platform is associated with the material of the battery cell.

[0100] Exemplarily, the processing device can obtain the standard charging voltage platform of the battery cell, and calculate the difference between the standard charging voltage platform of the battery cell and the current charging voltage platform to obtain the charging voltage platform offset of the battery cell.

[0101] Regarding the process of obtaining the standard charging voltage platform of the battery cell by the processing device, in some implementations, the BMS pre-stores the standard charging voltage platform of the battery cell, and the processing device can send an acquisition instruction to the BMS through the network, the BMS receives and responds to the acquisition instruction, and sends the pre-stored standard charging voltage platform of the battery cell to the processing device through the network, and the processing device receives the standard charging voltage platform returned by the BMS.

[0102] In some implementations, the processing device can obtain the battery cell identifier of the battery cell, and find the charging voltage platform table according to the battery cell identifier to obtain the standard charging voltage platform of the battery cell.

[0103] The processing device pre-stores a charging voltage platform table, which can be used to represent the correspondence between the battery cell identifier and the standard charging voltage platform. For example, the battery cell identifier can include, but is not limited to, battery cell A, battery cell B, battery cell C, and battery cell D, the standard charging voltage platform can include, but is not limited to, 3.5V, 3.65V, 3.7V, and 3.75V, and the correspondence between the battery cell identifier and the standard charging voltage platform can be as shown in Table 1, i.e., the charging voltage platform table. According to the correspondence, the standard charging voltage platform of the battery cell can be obtained.

[0104] Table 1

[0105] It should be noted that the correspondence between the standard charging voltage platform of the battery cell identifier is not limited to Table 1.

[0106] In some embodiments, the processing device can generate prompt information and receive the standard charging voltage platform of the battery cell uploaded by the user according to the prompt information.

[0107] The prompt information can be used to prompt the user to upload the standard charging voltage platform of the battery cell to the processing device, and the prompt information can include, but is not limited to, at least one of sound prompt information, text prompt information, and light prompt information.

[0108] Step 140: determining the differential capacity peak value change rate of the battery cell according to the change rate of the current differential capacity peak value of the battery cell relative to the standard differential capacity peak value.

[0109] In the embodiments of the present application, the processing device can obtain the standard differential capacity peak value of the battery cell, and determine the differential capacity peak value change rate of the battery cell according to the change rate of the current differential capacity peak value of the battery cell relative to the standard differential capacity peak value.

[0110] The standard differential capacity peak value of the battery cell is a differential capacity peak value pre-calibrated by the user, and the standard differential capacity peak value is associated with the material of the battery cell. For example, the standard differential capacity peak value is the differential capacity peak value corresponding to the target differential capacity curve of a normal battery cell.

[0111] For example, the processing device can obtain the standard differential capacity peak value of the battery cell, and calculate the change rate of the current differential capacity peak value of the battery cell relative to the standard differential capacity peak value to obtain the differential capacity peak value change rate of the battery cell. The calculation of the differential capacity peak value change rate of the battery cell can include: obtaining the absolute value of the difference between the current differential capacity peak value and the standard differential capacity peak value; and dividing the absolute value of the difference between the current differential capacity peak value and the standard differential capacity peak value by the standard differential capacity peak value to obtain the change rate of the current differential capacity peak value relative to the standard differential capacity peak value.

[0112] Regarding the process of obtaining the standard differential capacity peak value of the battery cell by the processing device, in some embodiments, the BMS pre-stores the standard differential capacity peak value of the battery cell, the processing device can send an obtaining instruction to the BMS through the network, the BMS receives and responds to the obtaining instruction, and sends the pre-stored standard differential capacity peak value of the battery cell to the processing device through the network, and the processing device receives the standard differential capacity peak value returned by the BMS.

[0113] In some embodiments, the processing device can obtain the battery cell identifier of the battery cell, and find the differential capacity peak value table according to the battery cell identifier to obtain the standard differential capacity peak value of the battery cell.

[0114] In some embodiments, the processing device pre-stores the differential capacity peak value table, and the differential capacity peak value table can be used to represent the correspondence between the battery cell identifier and the standard differential capacity peak value. For example, the battery cell identifier can include but is not limited to battery cell A, battery cell B, and battery cell C, and the standard differential capacity peak value can include but is not limited to 222 milliampere-hour / millivolt (mAh / mV).

[0115] Step 150: determining the current capacity attenuation rate corresponding to the first n cycles of the N cycles of charging and discharging according to the capacity attenuation curve, N / 300≤n≤N / 140, N and n are integers, and n is greater than 1.

[0116] The first n cycles refer to the first cycle to the n th cycle. N / 300≤n≤N / 140, that is, the value of n is smaller than N, and the current capacity attenuation rate corresponding to the first n cycles of the N cycles of charging and discharging is obtained. Affected by the anode tab missing coating, a large amount of lithium ions in the cathode tab are precipitated to the anode tab missing coating position during the first n cycles of charging and discharging, resulting in a large amount of lithium precipitation, and thus the capacity attenuation rate offset of the first n cycles of charging and discharging is large. With the increase of the cycle number, the lithium precipitation and dissolution at the anode tab missing coating position reach equilibrium, and the capacity attenuation rate offset of the n+1 th cycle to the N th cycle of charging and discharging gradually decreases to close to 0. For example, n can be 5, and N can be 700, 800, 1400, or 1500, etc.

[0117] In the embodiments of the present application, in the case that the user needs to detect the anode tab missing coating defect of the battery cell, a detection instruction can be sent to the processing device, the processing device receives and responds to the detection instruction, and obtains the current capacity attenuation rate corresponding to the first n cycles of charging and discharging. The current capacity attenuation rate corresponding to the first n cycles of charging and discharging refers to the capacity attenuation rate corresponding to each cycle of charging and discharging in the first cycle to the n th cycle of charging and discharging.

[0118] Step 160: determining the capacity attenuation rate offset corresponding to the first n cycles of charging and discharging according to the standard capacity attenuation rate and the current capacity attenuation rate of the battery cell.

[0119] In the embodiments of the present application, the processing device can obtain a standard capacity attenuation rate of the battery cell, and determine a capacity attenuation rate offset corresponding to the n previous cycle charging and discharging according to the standard capacity attenuation rate and the current capacity attenuation rate of the battery cell. The capacity attenuation rate offset can be obtained according to the standard capacity attenuation rate and the current capacity attenuation rate of the battery cell, which can include obtaining an absolute value of a difference between the current capacity attenuation rate and the standard capacity attenuation rate.

[0120] The capacity attenuation rate of the battery cell is a capacity attenuation rate pre-labeled by a user, and the standard capacity attenuation rate is associated with the material of the battery cell. For example, the standard capacity attenuation rate is a capacity attenuation rate corresponding to a capacity attenuation curve of a normal battery cell. The capacity attenuation rate offset corresponding to the n previous cycle charging and discharging can be determined, which can include obtaining an offset of the current capacity attenuation rate of the battery cell corresponding to each cycle charging and discharging with respect to the standard capacity attenuation rate. For example, the offset of the current capacity attenuation rate corresponding to the n th cycle charging and discharging with respect to the standard capacity attenuation rate can be obtained, which can include obtaining the current capacity attenuation rate corresponding to the n th cycle charging and discharging and the standard capacity attenuation rate corresponding to the n th cycle charging and discharging in the capacity attenuation curve of the normal battery cell, and calculating the offset of the current capacity attenuation rate corresponding to the n th cycle charging and discharging with respect to the standard capacity attenuation rate according to the obtained current capacity attenuation rate and the standard capacity attenuation rate.

[0121] For example, the processing device can obtain a standard capacity attenuation rate of the battery cell, and calculate a difference between the current capacity attenuation rate and the standard capacity attenuation rate of the battery cell to obtain a capacity attenuation rate offset of the battery cell.

[0122] Regarding the process of obtaining the standard capacity attenuation rate of the battery cell by the processing device, in some embodiments, the BMS pre-stores the standard capacity attenuation rate of the battery cell, the processing device can send an obtaining instruction to the BMS through the network, the BMS receives and responds to the obtaining instruction, sends the pre-stored standard capacity attenuation rate of the battery cell to the processing device through the network, and the processing device receives the standard capacity attenuation rate returned by the BMS.

[0123] In some embodiments, the processing device can obtain a battery cell identifier of the battery cell, and obtain the standard capacity attenuation rate of the battery cell according to the battery cell identifier.

[0124] The processing device pre-stores a capacity attenuation rate table, and the capacity attenuation rate table can be used to represent the corresponding relationship between the battery cell identifier and the standard capacity attenuation rate.

[0125] Step 170: determining that the anode tab missing coating defect exists in the battery cell in a case that the charging voltage platform offset is greater than or equal to the charging voltage platform offset threshold, the differential capacity peak change rate is greater than or equal to the differential capacity peak change rate threshold, and the capacity attenuation rate offset corresponding to the previous n times of cycle charging and discharging is all greater than the capacity attenuation rate offset threshold.

[0126] In the embodiment of the present application, the processing device can determine that the anode tab missing coating defect exists in the battery cell in a case that the charging voltage platform offset is greater than or equal to the charging voltage platform offset threshold, the differential capacity peak change rate is greater than or equal to the differential capacity peak change rate threshold, and the capacity attenuation rate offset corresponding to the previous n times of cycle charging and discharging is all greater than the capacity attenuation rate offset threshold. In the charging process of the battery cell, in the case that the anode tab has the missing coating defect, the anode tab missing coating position exposes copper, and the lithium ion is oxidized and reduced at the exposed copper position. Compared with the anode tab that is not missing coating, the anode potential of the anode tab that is missing coating is smaller, and the charging voltage platform and the differential capacity peak of the battery cell are greatly offset. Moreover, due to the influence of the anode tab missing coating, a large amount of lithium ion is precipitated to the anode tab missing coating position in the previous n times of cycle charging and discharging process, resulting in a large amount of lithium precipitation, thereby causing the capacity attenuation rate offset of the previous n times of cycle charging and discharging to be large. With the increase of the cycle number, the lithium precipitation and the dissolved lithium at the anode tab missing coating position reach a balance, and the capacity attenuation rate offset of the n+1th to Nth cycle charging and discharging gradually decreases to close to 0. Therefore, by combining the charging voltage platform offset, the differential capacity peak change rate, and the capacity attenuation rate offset corresponding to the previous n times of cycle charging and discharging, the missing coating defect of the anode tab of the battery cell is detected, which is beneficial to improve the detection accuracy of detecting the missing coating defect of the anode tab of the battery cell.

[0127] The charging voltage platform offset threshold can be used to represent the minimum charging voltage platform offset of the battery cell with the anode missing coating defect. The charging voltage platform offset threshold can include but is not limited to the minimum charging voltage platform offset preset by the user, and the minimum charging voltage platform offset automatically generated by the processing device according to the detection process of multiple anode missing coating defect detections.

[0128] As an example, the charging voltage platform offset threshold can be set to 10 mV, the charging voltage platform offset threshold can also be set to 15 mV, the charging voltage platform offset threshold can also be set to 50 mV, and the like.

[0129] The differential capacity peak change rate threshold can be used to represent the minimum differential capacity peak change rate of the battery cell with the anode missing coating defect. The differential capacity peak change rate threshold can include but is not limited to the minimum differential capacity peak change rate preset by the user, and the minimum differential capacity peak change rate automatically generated by the processing device according to the detection process of multiple anode missing coating defect detections.

[0130] As an example, the differential capacity peak change rate threshold value can be set to 5% or the like.

[0131] The capacity fade rate offset threshold value can be used to represent the maximum capacity fade rate offset of the absence of anode coating defect of the battery cell, and the capacity fade rate offset threshold value can include but is not limited to the maximum capacity fade rate offset preset by the user, and the maximum capacity fade rate offset automatically generated by the detection process according to multiple anode coating defect detections of the processing device.

[0132] As an example, the capacity fade rate offset threshold value can be set to 0.03% or the like, and n can be 5, that is, if the capacity fade rate offset corresponding to each of the first five cycle charging and discharging is greater than 0.03%, it is considered that the anode exists coating defect.

[0133] In some embodiments, the charging voltage platform offset is less than the charging voltage platform offset threshold value, and / or the differential capacity peak change rate is less than the differential capacity peak change rate threshold value, and / or the capacity fade rate offset corresponding to at least one of the first n cycle charging and discharging is less than or equal to the capacity fade rate offset threshold value, the determination of the absence of the anode tab coating defect of the battery cell based on the charging voltage platform offset is beneficial to improve the judgment accuracy of the judgment of the anode tab coating defect of the battery cell.

[0134] In other words, if any one of the three conditions that the charging voltage platform offset is greater than or equal to the charging voltage platform offset threshold value, the differential capacity peak change rate is greater than or equal to the differential capacity peak change rate threshold value, and the capacity fade rate offset corresponding to the first n cycle charging and discharging is greater than the capacity fade rate offset threshold value is not met, it is considered that the anode tab does not exist coating defect.

[0135] In one application scenario, during the charging process of the battery cell, the processing device can collect n groups of charging parameters of the battery cell according to the BMS at a preset time interval dT, each group of charging parameters can include a charging current, an initial battery cell voltage and a target battery cell voltage, for example, the i th group of charging parameters can include the i th group of charging current I i , the i th group of initial battery cell voltage V′ i and the i th group of target battery cell voltage V″ i .

[0136] The i th group of charging current I i is the average current during the charging process of the i th group of preset time interval.

[0137] The processing device can calculate the i th group of charging voltage platform offset according to the i th group of initial battery cell voltage V′ iand the i-th group target cell voltage V" i , the i-th group cell voltage change dV i corresponding to the i-th group charging parameter is calculated according to Formula One.

[0138] Formula One is: dV i = V" i -V' i .

[0139] The processing device can calculate the i-th group cell capacity change dQ i corresponding to the i-th group charging parameter according to Formula Two, based on the i-th group charging current I i of the i-th group charging parameter and a preset time interval dT.

[0140] Formula Two is: dQ i = I i · dT.

[0141] The processing device can calculate the i-th group differential capacity dQ i / dV i corresponding to the i-th group charging parameter according to Formula Three, based on the i-th group cell voltage change dV i and the i-th group cell capacity change dQ i .

[0142] Formula Three is: dQ i / dV i = (I i · dT) / (V" i -V' i ).

[0143] The processing device can construct an initial differential capacity curve according to the differential capacity dQ1 / dV1 under the first group target cell voltage V"1, the differential capacity dQ2 / dV2 under the second group target cell voltage V"2, …, and the differential capacity dQ n / dV n under the n-th group target cell voltage V" n , and perform smoothing processing on the initial differential capacity curve to obtain a target differential capacity curve.

[0144] The processing device can determine a differential capacity peak value according to the target differential capacity curve, and determine the target cell voltage corresponding to the differential capacity peak value as the current charging voltage plateau of the cell.

[0145] In some embodiments, a plurality of capacity attenuation rates of the battery cell under N times of cyclic charging and discharging can be determined, and an initial capacity attenuation curve can be constructed according to the plurality of capacity attenuation rates and the number of times of cyclic charging and discharging, and the initial capacity attenuation curve can be smoothed to obtain a capacity attenuation curve. The horizontal coordinate of the capacity attenuation curve is the number of times of cyclic charging and discharging, and the vertical coordinate is the capacity attenuation rate.

[0146] The processing device can determine a current capacity attenuation rate corresponding to the first n times of cyclic charging and discharging in the N times of cyclic charging and discharging according to the capacity attenuation curve. The processing device can smooth the initial differential capacity curve and the initial capacity attenuation curve based on a preset algorithm to obtain a target differential capacity curve and the capacity attenuation curve. The preset algorithm can include but is not limited to any one of Gaussian Smoothing algorithm, Moving Average algorithm, Douglas-Peucke algorithm, and local weighted regression algorithm.

[0147] In an application scenario, as shown in FIG. 2, a scenario diagram of initial differential capacity curves of different battery cells is shown. The first initial differential capacity curve of a normal battery cell, the second initial differential capacity curve of an abnormal battery cell 1, and the third initial differential capacity curve of an abnormal battery cell 2 are shown in FIG. 2.

[0148] The processing device can respectively smooth the first initial differential capacity curve of the normal battery cell to obtain a first target differential capacity curve, smooth the second initial differential capacity curve of the abnormal battery cell 1 to obtain a second target differential capacity curve, and smooth the third initial differential capacity curve of the abnormal battery cell 2 to obtain a third target differential capacity curve, as shown in FIG. 3.

[0149] In an application scenario, as shown in FIG. 4, a scenario diagram of capacity attenuation curves of different battery cells after smoothing is shown. The first capacity attenuation curve of a normal battery cell, the second capacity attenuation curve of an abnormal battery cell 1, and the third capacity attenuation curve of an abnormal battery cell 2 are shown in FIG. 4.

[0150] In some embodiments, the processing device can generate and store a detection record containing the battery cell identifier and the defect detection result, so that the user can trace the detection process of the anode tab coating defect detection of the battery cell according to the detection record, which is beneficial to improve the user experience in the process of detecting the anode tab coating defect of the battery cell.

[0151] The defect detection result can include a first defect detection result for indicating that the battery cell has the anode tab coating defect, and a second defect detection result for indicating that the battery cell does not have the anode tab coating defect.

[0152] The scheme provided in the application determines the current charging voltage platform and the current differential capacity peak value of the battery cell, determines the charging voltage platform offset of the battery cell according to the standard charging voltage platform and the current charging voltage platform of the battery cell, determines the differential capacity peak value change rate of the battery cell according to the standard differential capacity peak value and the current differential capacity peak value of the battery cell, and determines the current capacity attenuation rate corresponding to the n-time cycle charging and discharging in the N-time cycle charging and discharging according to the capacity attenuation curve of the battery cell, N / 300≤n≤N / 140, N and n are integers, and n is greater than 1. The capacity attenuation rate offset corresponding to the n-time cycle charging and discharging is determined according to the standard capacity attenuation rate and the current capacity attenuation rate of the battery cell. In the case that the charging voltage platform offset is greater than or equal to the charging voltage platform offset threshold, the differential capacity peak value change rate is greater than or equal to the differential capacity peak value change rate threshold, and the capacity attenuation rate offset corresponding to the n-time cycle charging and discharging is all greater than the capacity attenuation rate offset threshold, it is determined that the battery cell has an anode tab coating defect. In the charging process of the battery cell, the anode tab has a coating defect, the copper is exposed at the coating defect of the anode tab, the lithium ion undergoes oxidation and reduction reaction at the exposed copper, the anode potential of the anode tab is smaller than that of the anode tab without coating, and the charging voltage platform of the battery cell is greatly offset. Therefore, based on the charging voltage platform offset, the differential capacity peak value change rate and the capacity attenuation rate offset corresponding to the n-time cycle charging and discharging of the battery cell, the coating defect of the anode tab of the battery cell is detected, which is beneficial to improve the detection accuracy of the coating defect of the anode tab of the battery cell.

[0153] Please refer to FIG. 5, which shows a flow chart of the tab coating defect detection method provided in another embodiment of the application. In specific embodiments, the tab coating defect detection method can be applied to a processing device. In the following, the flow shown in FIG. 5 will be described in detail taking the processing device as an example. The tab coating defect detection method can include the following steps 110 to 180.

[0154] Step 110: Determine the target differential capacity curve and the capacity attenuation curve of the battery cell.

[0155] Step 120: Determine the current charging voltage platform and the current differential capacity peak value of the battery cell according to the target differential capacity curve.

[0156] Step 130: Determine the charging voltage platform offset of the battery cell according to the standard charging voltage platform and the current charging voltage platform of the battery cell.

[0157] Step 140: Determine the differential capacity peak value change rate of the battery cell according to the change rate of the current differential capacity peak value relative to the standard differential capacity peak value.

[0158] Step 150: determining a current capacity attenuation rate corresponding to the n th cycle of the N cycles of charging and discharging according to the capacity attenuation curve, N / 300≤n≤N / 140, N and n are integers, and n is greater than 1.

[0159] Step 160: determining a capacity attenuation rate offset corresponding to the n th cycle of the N cycles of charging and discharging according to the standard capacity attenuation rate and the current capacity attenuation rate of the battery cell.

[0160] Step 170: determining that the battery cell has the anode tab missing defect when the charging voltage platform offset is greater than or equal to the charging voltage platform offset threshold, the differential capacity peak change rate is greater than or equal to the differential capacity peak change rate threshold, and the capacity attenuation rate offset corresponding to the n th cycle of the N cycles of charging and discharging is greater than the capacity attenuation rate offset threshold.

[0161] In the embodiment, steps 110 to 170 can refer to the content of the corresponding steps in the foregoing embodiments, which will not be described here again.

[0162] Step 180: generating the alarm information.

[0163] In the embodiment, the processing device can generate the alarm information when it is determined that the battery cell has the anode tab missing defect, so that the user can process the battery cell according to the alarm information, avoid the battery cell from being unable to normally conduct electricity and dissipate heat due to the anode tab missing during the charging process, and lead to thermal runaway, and thus the charging safety of the battery cell is improved.

[0164] The alarm information can include at least one of the following, but is not limited to: a text alarm information, a sound alarm information, a light alarm information, and the like.

[0165] The scheme provided by the embodiment determines the current charging voltage platform and the current differential capacity peak value of the battery cell, determines the charging voltage platform offset of the battery cell according to the standard charging voltage platform and the current charging voltage platform of the battery cell, determines the differential capacity peak value change rate of the battery cell according to the standard differential capacity peak value and the current differential capacity peak value of the battery cell, determines the current capacity attenuation rate corresponding to the n th cycle of the N-cycle charging and discharging according to the capacity attenuation curve of the battery cell, N / 300≤n≤N / 140, N and n are integers, and n is greater than 1, determines the capacity attenuation rate offset corresponding to the n th cycle of the N-cycle charging and discharging according to the standard capacity attenuation rate and the current capacity attenuation rate of the battery cell, and determines that the battery cell has an anode tab coating defect in the case that the charging voltage platform offset is greater than or equal to the charging voltage platform offset threshold, the differential capacity peak value change rate is greater than or equal to the differential capacity peak value change rate threshold, and the capacity attenuation rate offset corresponding to the n th cycle of the N-cycle charging and discharging is all greater than the capacity attenuation rate offset threshold, and generates an alarm information. In the case that the anode tab has a coating defect during the charging process of the battery cell, the copper is exposed at the anode tab coating defect, the lithium ion undergoes oxidation and reduction reaction at the exposed copper, the anode potential of the anode tab is smaller than that of the anode tab without coating, and the charging voltage platform, the differential capacity peak value and the capacity attenuation rate corresponding to the n th cycle of the N-cycle charging and discharging of the battery cell are greatly offset. Therefore, the anode tab of the battery cell is detected for the coating defect based on the charging voltage platform offset, the differential capacity peak value change rate and the capacity attenuation rate offset corresponding to the n th cycle of the N-cycle charging and discharging, which is beneficial to improve the detection accuracy of the anode tab coating defect of the battery cell.

[0166] Further, the alarm information is generated in the case that the battery cell has an anode tab coating defect, so that the user processes the battery cell according to the alarm information, avoids the battery cell from being unable to normally conduct electricity and dissipate heat due to the anode tab coating defect during the charging process, and causes thermal runaway, which is beneficial to improve the charging safety of the battery cell.

[0167] Please refer to FIG. 6, which shows the tab coating defect detection device 300 provided by an embodiment of the application. In specific embodiments, the tab coating defect detection device 300 can be applied to a processing device. In the following, the tab coating defect detection device 300 shown in FIG. 6 will be described in detail by taking the processing device as an example. The tab coating defect detection device 300 can include a first determination module 310, a second determination module 320, a fourth determination module 340, a fifth determination module 350, a sixth determination module 360 and a third determination module 330.

[0168] The first determination module 310 can be configured to determine a target differential capacity curve of the battery cell, and determine a current charging voltage plateau and a current differential capacity peak of the battery cell according to the target differential capacity curve; the second determination module 320 can be configured to determine a charging voltage plateau offset of the battery cell according to a standard charging voltage plateau and the current charging voltage plateau of the battery cell; the fourth determination module 340 can be configured to determine a differential capacity peak change rate of the battery cell according to a change rate of the current differential capacity peak of the battery cell relative to a standard differential capacity peak; the fifth determination module 350 can be configured to determine a capacity attenuation curve of the battery cell, and determine a current capacity attenuation rate corresponding to n times of cycle charging and discharging in N times of cycle charging and discharging according to the capacity attenuation curve, N / 300≤n≤N / 140, N and n are integers, and n is greater than 1; the sixth determination module 360 can be configured to determine a capacity attenuation rate offset corresponding to n times of cycle charging and discharging according to a standard capacity attenuation rate and the current capacity attenuation rate of the battery cell; and the third determination module 330 can be configured to determine that the battery cell has an anode tab coating defect when the charging voltage plateau offset is greater than or equal to a charging voltage plateau offset threshold, the differential capacity peak change rate is greater than or equal to a differential capacity peak change rate threshold, and the capacity attenuation rate offset corresponding to n times of cycle charging and discharging is greater than a capacity attenuation rate offset threshold.

[0169] In some embodiments, the first determination module 310 can include a first determination sub-module and a second determination sub-module.

[0170] The first determination sub-module can be configured to determine a target differential capacity curve of the battery cell; and the second determination sub-module can be configured to determine a current charging voltage plateau according to the target differential capacity curve.

[0171] In some embodiments, the second determination sub-module can include a first determination unit and a second determination unit.

[0172] The first determination unit can be configured to determine a differential capacity peak according to the target differential capacity curve; and the second determination unit can be configured to determine a current charging voltage plateau corresponding to a voltage of the battery cell at the differential capacity peak.

[0173] In some embodiments, the first determination sub-module can include a third determination unit and a construction unit.

[0174] The third determination unit can be configured to determine a plurality of differential capacities of the battery cell at a plurality of target battery cell voltages, each target battery cell voltage can correspond to one differential capacity; and the construction unit can be configured to construct a target differential capacity curve according to the plurality of differential capacities and the plurality of target battery cell voltages.

[0175] In some embodiments, the third determination unit can include an acquisition sub-unit and a determination sub-unit.

[0176] The collecting subunit can be configured to collect a plurality of groups of charging parameters of the battery cell at preset time intervals, each group of charging parameters can include a charging current, an initial battery cell voltage and a target battery cell voltage; the determining subunit can be configured to determine a differential capacity of the battery cell at a target battery cell voltage according to each group of charging parameters, to obtain a plurality of differential capacities.

[0177] In some embodiments, the determining subunit can include a first determining subunit, a second determining subunit and a calculating subunit.

[0178] The first determining subunit can be configured to determine a battery cell voltage variation according to an initial battery cell voltage and a target battery cell voltage of each group of charging parameters; the second determining subunit can be configured to determine a battery cell capacity variation according to a charging current and a preset time interval of each group of charging parameters; and the calculating subunit can be configured to calculate a differential capacity of the battery cell at a target battery cell voltage of each group of charging parameters according to a corresponding battery cell voltage variation and a battery cell capacity variation of each group of charging parameters.

[0179] In some embodiments, the fifth determining module 350 can include a fourth determining sub-module and a fifth determining sub-module.

[0180] The fourth determining sub-module can be configured to determine a capacity attenuation curve of the battery cell, and the fifth determining sub-module can be configured to determine a current capacity attenuation rate corresponding to the first n cycle charging and discharging among the N cycle charging and discharging according to the capacity attenuation curve.

[0181] In some embodiments, the third determining module 330 can include a third determining sub-module.

[0182] The third determining sub-module can be configured to determine that the battery cell does not have the anode tab missing defect when the charging voltage platform offset is less than the charging voltage platform offset threshold, the differential capacity peak variation rate is greater than or equal to the differential capacity peak variation rate threshold, and the capacity attenuation rate offset corresponding to the first n cycle charging and discharging is all greater than the capacity attenuation rate offset threshold.

[0183] The scheme provided by the embodiment determines the current charging voltage platform of the battery cell, and determines the charging voltage platform offset of the battery cell according to the standard charging voltage platform and the current charging voltage platform of the battery cell. In the case that the charging voltage platform offset is greater than or equal to the charging voltage platform offset threshold, it is determined that the battery cell has an anode tab coating defect. In the charging process of the battery cell, the anode tab has a coating defect, the copper is exposed at the coating defect of the anode tab, and the lithium ion is oxidized and reduced at the exposed copper. Compared with the anode of the anode tab without coating, the anode potential of the anode tab is smaller, and the charging voltage platform of the battery cell is greatly offset. Therefore, the anode tab coating defect of the battery cell is detected based on the charging voltage platform offset of the battery cell, which is beneficial to improve the detection accuracy of the anode tab coating defect of the battery cell.

[0184] It should be noted that each of the embodiments in the present specification is described in a progressive manner, and each embodiment focuses on the difference from other embodiments. The same and similar parts of each embodiment can be referred to each other. For the device embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the part of the method embodiment. For any processing manner described in the method embodiment, it can be realized by a corresponding processing module in the device embodiment, and the device embodiment will not be described one by one.

[0185] In addition, each functional module in each embodiment of the present application can be integrated in one processing module, or each module can exist physically, or two or more modules can be integrated in one module. The integrated module can be realized in the form of hardware or in the form of software functional module.

[0186] Please refer to FIG. 7, which shows the functional block diagram of the electronic device 500 provided by an embodiment of the present application. The electronic device 500 can include one or more of the following components: a memory 510, a processor 520, and one or more application programs, wherein the one or more application programs can be stored in the memory 510 and configured to be executed by the one or more processors 520, and the one or more application programs are configured to execute the method described in the foregoing method embodiments.

[0187] The memory 510 can include a random access memory (RAM) and can also include a read-only memory (ROM). The memory 510 can be used to store instructions, programs, codes, code sets, or instruction sets. The memory 510 can include a program storage area and a data storage area, where the program storage area can store instructions for implementing an operating system, instructions for implementing at least one function (such as determining a current charging voltage platform, determining a charging voltage platform offset, determining that the anode tab missing defect exists in the battery cell, determining a target differential capacity curve, determining a differential capacity peak value, determining a plurality of differential capacities, constructing a target differential capacity curve, collecting a plurality of charging parameters, determining a differential capacity, obtaining a plurality of differential capacities, determining a battery cell voltage variation, determining a battery cell capacity variation, calculating a differential capacity, and determining that the anode tab missing defect does not exist in the battery cell, etc.), instructions for implementing each of the method embodiments described below, and the like. The data storage area can also store data (such as a battery cell, a current charging voltage platform, a standard charging voltage platform, a charging voltage platform offset, an anode tab missing defect, a target differential capacity curve, a differential capacity peak value, a battery cell voltage, a plurality of target battery cell voltages, a plurality of differential capacities, a preset time interval, a plurality of charging parameters, a charging current, an initial battery cell voltage, a battery cell voltage variation, a battery cell capacity variation, and a charging voltage platform offset threshold) created by the electronic device 500 in use, and the like.

[0188] The processor 520 can include one or more processing cores. The processor 520 connects various parts within the entire electronic device 500 through various interfaces and lines, performs various functions of the electronic device 500 and processes data by running or executing instructions, program code sets, or instruction sets stored in the memory 510, and calling data stored in the memory 510. Optionally, the processor 520 can be implemented in at least one of a hardware form of a digital signal processing (DSP), a field-programmable gate array (FPGA), a programmable logic array (PLA). The processor 520 can integrate a combination of one or more of a central processing unit (CPU), a graphics processing unit (GPU), and a modem. Among them, the CPU mainly processes an operating system, a user interface, and an application program; the GPU is responsible for rendering and drawing display content; and the modem is used for processing wireless communication. It can be understood that the above-mentioned modem can also not be integrated into the processor 520, but can be implemented separately by a communication chip.

[0189] Referring to FIG. 8, a structural block diagram of a computer readable storage medium is shown according to an embodiment of the present application. The computer readable storage medium 600 stores program code 610, which can be invoked by a processor to execute the methods described in the above method embodiments.

[0190] 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 for the program code 610 to execute any of the above methods. These program codes can be read from or written to one or more computer program products. The program code 610 can be compressed in an appropriate form, for example.

[0191] Referring to FIG. 9, a structural block diagram of a computer program product 700 is shown according to an embodiment of the present application. The computer program product 700 includes computer programs / instructions 710 stored in a computer readable storage medium of a computer device. When the computer program product 700 runs on the computer device, the processor of the computer device reads the computer programs / instructions 710 from the computer readable storage medium, and the processor executes the computer programs / instructions 710, so that the computer device executes the methods described in the above method embodiments.

[0192] The scheme provided by the embodiment determines the current charging voltage platform and the current differential capacity peak value of the battery cell, determines the charging voltage platform offset of the battery cell according to the standard charging voltage platform and the current charging voltage platform of the battery cell, determines the differential capacity peak value change rate of the battery cell according to the standard differential capacity peak value and the current differential capacity peak value of the battery cell, and determines the current capacity attenuation rate corresponding to the first n times of cycle charging and discharging in the N times of cycle charging and discharging according to the capacity attenuation curve of the battery cell, N / 300≤n≤N / 140, N and n are integers, and n is greater than 1. The capacity attenuation rate offset corresponding to the first n times of cycle charging and discharging is determined according to the standard capacity attenuation rate and the current capacity attenuation rate of the battery cell. In the case that the charging voltage platform offset is greater than or equal to the charging voltage platform offset threshold, the differential capacity peak value change rate is greater than or equal to the differential capacity peak value change rate threshold, and the capacity attenuation rate offset corresponding to the first n times of cycle charging and discharging is greater than the capacity attenuation rate offset threshold, it is determined that the battery cell has an anode tab coating defect. In the charging process of the battery cell, the anode tab has a coating defect, the copper is exposed at the coating defect of the anode tab, the lithium ion is oxidized and reduced at the exposed copper, the anode potential of the anode tab is smaller than that of the anode tab without coating, and the charging voltage platform of the battery cell is greatly offset. Therefore, based on the charging voltage platform offset, the differential capacity peak value and the capacity attenuation rate offset corresponding to the first n times of cycle charging and discharging of the battery cell, the coating defect of the anode tab of the battery cell is detected, which is beneficial to improve the detection accuracy of the coating defect of the anode tab of the battery cell.

[0193] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art will understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not drive the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for detecting electrode coating defects, characterized in that, The method comprises: determining a target differential capacity curve and a capacity attenuation curve of the battery cell; determining a current charging voltage plateau and a current differential capacity peak of the battery cell according to the target differential capacity curve; determining a charging voltage plateau offset of the battery cell according to a standard charging voltage plateau and the current charging voltage plateau of the battery cell; determining a differential capacity peak change rate of the battery cell according to a change rate of the current differential capacity peak relative to a standard differential capacity peak of the battery cell; determining a current capacity attenuation rate corresponding to n cycles of charging and discharging in N cycles of charging and discharging according to the capacity attenuation curve, N / 300≤n≤N / 140, N and n are integers, and n is greater than 1; determining a capacity attenuation rate offset corresponding to n cycles of charging and discharging according to a standard capacity attenuation rate and the current capacity attenuation rate of the battery cell; determining that the battery cell has an anode tab coating defect when the charging voltage plateau offset is greater than or equal to a charging voltage plateau offset threshold, the differential capacity peak change rate is greater than or equal to a differential capacity peak change rate threshold, and the capacity attenuation rate offset corresponding to n cycles of charging and discharging is greater than a capacity attenuation rate offset threshold.

2. The pole piece undercoat defect detection method of claim 1, wherein The method comprises: determining the current charging voltage plateau according to the target differential capacity curve comprises: determining a differential capacity peak according to the target differential capacity curve; 3. The pole piece undercoat defect detection method of claim 1, wherein determining a battery cell voltage corresponding to the differential capacity peak as the current charging voltage plateau. The method comprises: determining a plurality of differential capacities of the battery cell at a plurality of target battery cell voltages, each target battery cell voltage corresponding to a differential capacity; 4. The pole piece undercoat defect detection method according to claim 3, characterized by, constructing the target differential capacity curve according to the plurality of differential capacities and the plurality of target battery cell voltages. The method comprises: collecting a plurality of sets of charging parameters of the battery cell at preset time intervals, each set of charging parameters comprising a charging current, an initial battery cell voltage, and a target battery cell voltage; 5. The pole piece undercoat defect detection method according to claim 4, characterized by, determining a differential capacity of the battery cell at the target battery cell voltage according to each set of charging parameters to obtain the plurality of differential capacities. The method comprises: determining a battery cell voltage change amount according to the initial battery cell voltage and the target battery cell voltage of each set of charging parameters; determining a battery cell capacity change amount according to the charging current and the preset time interval of each set of charging parameters; 6. The pole piece undercoat defect detection method according to any one of claims 1 to 5, characterized by, calculating the differential capacity of the battery cell at the target battery cell voltage of each set of charging parameters according to the battery cell voltage change amount and the battery cell capacity change amount corresponding to each set of charging parameters. The method further comprises: In a case that the charging voltage plateau offset is less than the charging voltage plateau offset threshold, and / or the differential capacity peak change rate is less than the differential capacity peak change rate threshold, and / or the capacity fade rate offset corresponding to at least one of the previous n cycle charge-discharge is less than or equal to the capacity fade rate offset threshold, it is determined that the anode tab coating defect does not exist in the battery cell.

7. An electrode tab undercoat defect detection device, characterized by, The method comprises: a first determining module configured to determine a target differential capacity curve of a battery cell, and determine a current charging voltage plateau and a current differential capacity peak of the battery cell according to the target differential capacity curve; a second determining module configured to determine a charging voltage plateau offset of the battery cell according to a standard charging voltage plateau and the current charging voltage plateau of the battery cell; a fourth determining module configured to determine a differential capacity peak change rate of the battery cell according to a change rate of the current differential capacity peak relative to a standard differential capacity peak of the battery cell; a fifth determining module configured to determine a capacity fade curve of the battery cell, and determine a current capacity fade rate corresponding to previous n cycle charge-discharge in N cycle charge-discharge according to the capacity fade curve, N / 300≤n≤N / 140, N and n are integers, and n is greater than 1; a sixth determining module configured to determine a capacity fade rate offset corresponding to the previous n cycle charge-discharge according to a standard capacity fade rate and the current capacity fade rate of the battery cell; a third determining module configured to determine that the anode tab coating defect exists in the battery cell in a case that the charging voltage plateau offset is greater than or equal to the charging voltage plateau offset threshold, the differential capacity peak change rate is greater than or equal to the differential capacity peak change rate threshold, and the capacity fade rate offset corresponding to the previous n cycle charge-discharge is greater than the capacity fade rate offset threshold.

8. An electronic device, comprising: The method comprises: a memory; one or more processors coupled to the memory; one or more application programs, wherein the one or more application programs are stored in the memory and configured to be executed by the one or more processors, and the one or more application programs are configured to execute the tab coating defect detection method according to any one of claims 1 to 6.

9. A computer readable storage medium, characterized in that, The computer readable storage medium stores program codes, and the program codes can be called and executed by the processor to execute the tab coating defect detection method according to any one of claims 1 to 6.

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