Battery cell tab welding abnormity detection method and system, storage medium and equipment

Abstract

The invention discloses a battery cell tab welding abnormity detection method and system, a storage medium and equipment. The battery cell tab welding abnormity detection method comprises the following steps: connecting a plurality of to-be-detected battery cells in parallel; performing constant-current charging and constant-current discharging on the to-be-detected battery cell; acquiring voltage data of the battery cell to be detected; establishing a voltage change curve of the to-be-detected battery cell according to the collected voltage data of the to-be-detected battery cell; and if the change value of the voltage data of the voltage change curve within the preset time is greater than a preset value, judging that the tab welding of the to-be-detected battery cell is abnormal. According to the detection method, voltage jump caused by tab defects in the charging and discharging process can be detected, local contact impedance changes are directly associated, voltage jump in a short time can be identified, and the detection sensitivity is improved.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and in particular to a method, system, storage medium, and device for detecting abnormal welding of battery cell tabs. Background Technology

[0002] In the battery manufacturing process, the welding quality between the tabs and the cell directly affects battery performance. Due to its multi-layer stacked structure, laminated batteries require welding at multiple tab locations.

[0003] In related technologies, the DC internal resistance detection method calculates the internal resistance value by measuring the voltage change of the battery cell under short-term charge and discharge pulses, thereby determining whether the tabs are abnormal. However, DC internal resistance reflects the overall impedance of the battery cell, and the internal resistance change caused by microcracks in the tabs is usually less than 1%, making it difficult to be effectively identified by conventional DC internal resistance detection equipment. Furthermore, DC internal resistance detection has low sensitivity. Summary of the Invention

[0004] The main objective of this invention is to provide a method, system, storage medium, and device for detecting abnormal welding of battery cell tabs, aiming to solve the technical problem of low sensitivity in DC internal resistance detection in related technologies.

[0005] To achieve the above-mentioned objective, the first aspect of this invention provides a method for detecting abnormal welding of battery cell tabs, comprising the following steps:

[0006] Connect multiple battery cells to be tested in parallel;

[0007] The battery cell under test is subjected to constant current charging and constant current discharging.

[0008] Collect the voltage data of the battery cell under test;

[0009] Based on the collected voltage data of the battery cell under test, a voltage change curve of the battery cell under test is established;

[0010] If the voltage change value of the voltage data in the voltage change curve is greater than the preset value within a preset time, it is determined that the electrode welding of the battery cell under test is abnormal.

[0011] In one embodiment, the steps of constant current charging and constant current discharging of the battery cell under test further include:

[0012] The battery cell to be tested is charged with constant current.

[0013] When the voltage of the battery cell to be tested reaches the first preset voltage, switch to constant voltage charging mode;

[0014] When the current in constant voltage charging mode reaches the first preset current, the charging process stops.

[0015] The battery cell under test is subjected to constant current discharge;

[0016] The discharge process stops when the voltage of the battery cell under test reaches the second preset voltage.

[0017] In one embodiment, after the step of stopping the discharge process when the voltage of the battery cell under test reaches a second preset voltage, the method further includes:

[0018] The battery cell under test is charged with constant current.

[0019] When the voltage of the battery cell under test reaches the third preset voltage, switch to constant voltage charging mode;

[0020] When the current in constant voltage charging mode reaches the second preset current, the charging process stops;

[0021] The third preset voltage is less than the first preset voltage.

[0022] In one embodiment, the first preset voltage is 4–4.2V; and / or

[0023] The second preset voltage is 2.8 to 3V.

[0024] In one embodiment, the step of determining that the tab welding of the battery cell under test is abnormal if the voltage data of the voltage change curve changes by a value greater than a preset value within a preset time includes:

[0025] If the voltage data of the voltage change curve during the constant current charging stage decreases by a greater than a preset value within a preset time, then the electrode welding of the cell under test is determined to be abnormal.

[0026] In one embodiment, the step of determining that the tab welding of the battery cell under test is abnormal if the voltage data of the voltage change curve changes by a value greater than a preset value within a preset time includes:

[0027] If the voltage data of the voltage change curve during the constant current discharge stage increases by a value greater than a preset value within a preset time, then the electrode welding of the cell under test is determined to be abnormal.

[0028] In one embodiment, the cell under test is charged with a constant current at a current rate of 0.1C to 0.5C; and / or

[0029] The cell under test is subjected to constant current discharge at a current ratio of 0.1C to 0.5C.

[0030] In one embodiment, the preset value is 5 to 10 mV.

[0031] In one embodiment, the voltage data of the cell under test is acquired by a four-wire voltage sampling method.

[0032] A second aspect of this invention provides a detection system for abnormal electrode tab welding in battery cells, comprising:

[0033] Parallel module, used to connect multiple cells to be tested in parallel;

[0034] A constant current charge / discharge module is used to perform constant current charging and constant current discharging on the battery cell under test;

[0035] The acquisition module is used to acquire the voltage data of the battery cell under test;

[0036] A module is established to establish a voltage change curve of the battery cell under test based on the collected voltage data of the battery cell under test;

[0037] The judgment module is used to determine that the electrode welding of the battery cell under test is abnormal if the change value of the voltage data of the voltage change curve within a preset time is greater than a preset value.

[0038] A third aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a computer processor, implements the above-described method for detecting abnormal welding of battery cell tabs.

[0039] A fourth aspect of the present invention provides a computer device for performing the above-described method for detecting abnormal welding of battery cell tabs.

[0040] Beneficial effects:

[0041] The present invention discloses a method for detecting abnormal electrode welding in battery cells, comprising the following steps: connecting multiple battery cells to be tested in parallel; performing constant current charging and constant current discharging on the battery cells to be tested; collecting voltage data of the battery cells to be tested; establishing a voltage change curve for the battery cells to be tested based on the collected voltage data; and determining that the electrode welding of the battery cells to be tested is abnormal if the voltage change value of the voltage data in the voltage change curve is greater than a preset value within a preset time. This detection method can detect voltage surges caused by electrode defects during charging and discharging, directly correlate with changes in local contact impedance, identify voltage surges within a short period of time, and improve detection sensitivity. Attached Figure Description

[0042] Figure 1 This is a flowchart of a method for detecting abnormal welding of battery cell tabs according to an embodiment of the present invention.

[0043] Figure 2 This is a voltage change curve according to an embodiment of the present invention.

[0044] Figure 3This is a voltage change curve with voltage abrupt change according to an embodiment of the present invention.

[0045] Figure 4 This is a parallel circuit system diagram according to an embodiment of the present invention.

[0046] Figure 5 This is a diagram of a four-wire voltage sampling circuit according to an embodiment of the present invention.

[0047] Figure 6 This is a diagram of a detection system according to an embodiment of the present invention.

[0048] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0049] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0050] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0051] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, a direct connection, or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0052] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0053] like Figure 1 As shown, in some embodiments, the method for detecting abnormal cell tab welding includes the following steps:

[0054] S100: Connect multiple cells to be tested in parallel.

[0055] S200: Perform constant current charging and constant current discharging on the battery cell to be tested.

[0056] S300: Collect voltage data of the battery cell under test.

[0057] S400. Based on the collected voltage data of the battery cell under test, establish the voltage change curve of the battery cell under test, such as... Figure 2 and Figure 3 As shown.

[0058] S500. If the voltage change value of the voltage data in the voltage change curve is greater than the preset value within a preset time, it is determined that the electrode tab welding of the cell under test is abnormal.

[0059] It should be noted that in the lithium battery manufacturing process, the welding quality between the tabs and the cell directly affects battery performance. Due to their multi-layered stacked structure, stacked batteries require welding at multiple tab sites. Traditional testing methods (such as visual inspection and X-ray imaging) suffer from low efficiency, high cost, inability to monitor in real time, and inability to detect already packaged cells. Existing electrochemical testing methods mostly rely on capacity decay or changes in internal resistance to identify anomalies, but they lack sufficient sensitivity for defects such as microcracks in the tabs, tab breakage, and partial breakage.

[0060] In existing technologies, the DC internal resistance detection method calculates the internal resistance value by measuring the voltage change of the battery cell under short-term charge and discharge pulses to determine whether the tab is abnormal. This method suffers from insufficient sensitivity, low time resolution, and a high risk of false positives. The internal resistance change caused by microcracks in the tab is typically less than 1%, making it difficult to effectively identify with conventional DC internal resistance detection equipment. Furthermore, DC internal resistance detection requires a single pulse after static rest, making it impossible to capture transient voltage fluctuations caused by tab defects during charge and discharge in real time, resulting in low resolution. This application addresses this by real-time monitoring of the dynamic voltage curve throughout the entire charge and discharge cycle, directly capturing the instantaneous voltage surges caused by tab defects, and directly correlating this with changes in local contact impedance. This allows for the identification of short-term voltage surges, improving detection sensitivity.

[0061] The detection principle of this detection method is as follows:

[0062] Under constant current discharge conditions: V (t) ≈OCV(SOC0-it / C n )-IR Ω .

[0063] Under constant current and constant voltage charging conditions: V (t) ≈OCV(SOC0-it / C n )+IR Ω .

[0064] According to the above formula, the voltage is sampled every 20 seconds during battery charging and discharging. Because the battery cells are stacked, if one of the tabs breaks during discharge, the current path is interrupted. At the instant the circuit is disconnected, I→0, and the voltage rises back to OCV (no ohms and no polarization voltage drop). V 瞬间 =OCV(SOC) (t) The voltage is greater than the original discharge voltage. Therefore, the voltage shows a sharp spike, such as... Figure 3 The portion shown at point B. Similarly, during charging, the voltage experiences a sharp drop, therefore... Figure 3 The portion shown at point A in the middle.

[0065] Specifically, the preset time is less than or equal to 10 seconds. This preset value can be adjusted according to the device's accuracy. The higher the device accuracy, the lower the preset value can be. The lower the device accuracy, the higher the preset value can be. The preset value is 5–10 mV. More specifically, the preset value can be 5 mV.

[0066] The following is the voltage surge threshold verification data:

[0067]

[0068] Specifically, welding abnormalities include microcracks, incomplete welds, and fractures.

[0069] Specifically, this detection method can be applied to the detection of lithium batteries.

[0070] Specifically, this testing method can be applied to stacked pouch cells. Stacked pouch cells employ a multi-layer electrode stacking design. The tabs need to be welded to each layer of electrodes at multiple points. The number of welding points is far greater than in wound cells. Stacked pouch cells have a higher probability of developing latent defects such as microcracks, incomplete welds, and partial fractures. When a defect occurs in a tab of a certain layer, the voltage data during constant current charging and discharging will suddenly change. Therefore, this testing method is suitable for stacked pouch cells.

[0071] like Figure 5 As shown, in some embodiments, voltage data of the battery cell under test is acquired using a four-wire voltage sampling method. The four-wire voltage sampling uses a four-wire Kelvin connection. The core of four-wire voltage sampling is to separate the current transmission path from the voltage measurement path, eliminating interference from lead resistance and cell internal resistance. Specifically, the circuit includes current lines and voltage lines. The current lines are responsible for transmitting the constant current for charging and discharging. The resistance of the current lines will cause a voltage drop as the current changes. The voltage lines are only used to acquire the actual voltage across the battery cell and do not carry the main current. Therefore, four-wire voltage sampling can reduce measurement errors caused by current line resistance and cell internal resistance at connection points.

[0072] In some embodiments, S100, multiple cells to be tested are connected in parallel. Because of the parallel connection, the normal testing of other cells is not affected, thus enabling multi-point cell testing. The timestamp of the voltage mutation point is used to associate the electrode welding position. Abnormal cells require individual stopping of charging and discharging, and the time and location of the abnormality are recorded. That is, the parallel connection method allows multiple cells to be tested simultaneously for charging and discharging, eliminating the need for testing each cell individually, significantly improving the efficiency of full inspection on the production line, and solving the problem of excessively long testing time for traditional single cells. Figure 4 As shown, the charging / discharging cabinet can have 40 channels. One end of each channel is the positive terminal, and the other end is the negative terminal. The battery cells are separated by partitions. During charging, the positive and negative clamps engage the positive and negative terminals of the battery cell, respectively, to begin charging. Line voltage is the voltage across the wires connected to the motherboard (drive box) (including the battery cell voltage + wire voltage). Terminal voltage is the voltage across the two terminals of the battery cell.

[0073] In some embodiments, S200, the steps of constant current charging and constant current discharging of the battery cell under test, further include:

[0074] S210. Perform constant current charging on the battery cell to be tested.

[0075] S220. When the voltage of the battery cell to be tested reaches the first preset voltage, switch to constant voltage charging mode.

[0076] S230. When the current in constant voltage charging mode reaches the first preset current, the charging process stops.

[0077] S240. Perform constant current discharge on the battery cell to be tested.

[0078] S250. When the voltage of the cell to be tested reaches the second preset voltage, the discharge process is stopped.

[0079] It should be noted that a constant current module is used to charge the battery cell under test at a constant current. The current accuracy is controlled within ±20mA. The constant current module is adjusted through closed-loop feedback, sampling and correcting the current value three times per second.

[0080] The closed-loop feedback of the constant current module ensures the stability of the total current flowing through the parallel cells, during which the cell voltage gradually increases. When the voltage reaches the first preset voltage, it enters the constant voltage charging mode. The constant voltage module maintains the first preset voltage output. According to the formula I = (U1 - U2) / (R1 + R2), as the cell charge saturates and the internal resistance R2 increases, the charging current gradually decreases until it reaches the first preset current. After the cell current reaches the first preset current, charging stops to avoid overcharging. Subsequently, the cell is discharged at a constant current rate at the same current ratio to gradually decrease the cell voltage until it reaches the second preset voltage, thus completing one charge-discharge cycle.

[0081] Specifically, the first preset voltage is the charging cutoff voltage. The first preset voltage is 4 to 4.2V. More specifically, the first preset voltage can be 4.2V.

[0082] Specifically, the second preset voltage is the discharge cutoff voltage. The second preset voltage is 2.8–3V. More specifically, the second preset voltage is 2.8V.

[0083] It should be noted that the charge / discharge voltage range of lithium batteries closely matches the electrochemical window of electrode materials (such as ternary materials and lithium iron phosphate). For stacked pouch cells, 4.2V is the fully charged voltage of a ternary system cell. 2.8V is the lower limit voltage for discharge termination; this range fully covers the entire active reaction process of the cell from full charge to complete discharge.

[0084] When the cell voltage reaches 4.2V, the reaction of lithium ions embedding into the positive electrode inside the cell approaches saturation, and the tabs serve as the critical path for current conduction. If defects such as poor soldering or microcracks exist, the instantaneous increase in the cell's internal resistance at high current densities (0.1C to 0.5C) will cause a voltage drop. Furthermore, 4.2V serves as a stable cutoff point, providing a benchmark for quantifying the magnitude of the voltage drop.

[0085] When the cell voltage discharges to 2.8V, the reaction of lithium ions separating from the positive electrode and embedding into the negative electrode is about to end. A tab defect can cause the current path to be interrupted, resulting in a sudden voltage spike back to the open-circuit voltage. The 2.8V setting ensures the discharge process is complete, preventing premature termination and ensuring that defect characteristics are not apparent.

[0086] In some embodiments, the cell under test is charged with a constant current at a current rate of 0.1C to 0.5C. Specifically, the cell under test is charged with a constant current at a current rate of 0.33C.

[0087] The cell under test is subjected to constant current discharge at a current rate of 0.1C to 0.5C. Specifically, the cell under test is subjected to constant current discharge at a current rate of 0.33C.

[0088] It should be noted that this current rate range is suitable for the multi-layer tab structure of stacked batteries. A current rate of 0.1C to 0.5C will not excessively impact the tabs and can stably induce changes in the cell's internal resistance at defective locations. Figure 6 As shown, the rate range within this interval represents standard parameters for lithium battery formation and capacity testing processes, and can be directly integrated into the online testing workflow. The charging and discharging cabinet control system integrates multiple lower-level machines (formation and capacity testing equipment) into a single upper-level machine (battery information management system). This upper-level machine can control multiple lower-level machines, and then transmit the data to a database for analysis and storage.

[0089] In some embodiments, after step S250, when the voltage of the cell to be tested reaches the second preset voltage, the step further includes:

[0090] S251. Perform constant current charging on the battery cell to be tested.

[0091] S252. When the voltage of the battery cell to be tested reaches the third preset voltage, switch to constant voltage charging mode.

[0092] S253. When the current in constant voltage charging mode reaches the second preset current, the charging process stops. The third preset voltage is less than the first preset voltage.

[0093] It should be noted that in step S251, when performing constant current charging on the cell under test, the second charge can be initiated using the same current rate as the previous charge-discharge cycle. This step can also adjust the third preset voltage according to the cell type. The second charge further excites the voltage characteristics of the tab defects in a lower voltage range. For example, a microcrack in the tab may cause a sudden drop in voltage during low-voltage charging due to changes in the cell's internal resistance, forming cross-validation with the previous charge-discharge data and improving detection reliability. Combining the two sudden voltage drops allows for a more accurate determination of localized weld cracks on the tab.

[0094] In some embodiments, S500, the step of determining that the electrode welding of the cell under test is abnormal if the voltage data of the voltage change curve changes by more than a preset value within a preset time period includes:

[0095] S510. If the voltage data of the voltage change curve during the constant current charging stage decreases by a greater than a preset value within a preset time, it is determined that the electrode tab welding of the cell under test is abnormal.

[0096] It should be noted that, specifically, the voltage data from the four-wire sampling module is first retrieved in real time through the data processing system. The sampling interval can be 20 seconds, with a resolution ≤1mV. An improved sliding window algorithm is used, with a window width of 10 sampling points and a step size of 1 point. The voltage difference between adjacent sampling points is calculated. When the voltage drop within a single cycle exceeds a preset value, the electrode tab welding of the cell under test is determined to be abnormal.

[0097] In some embodiments, S500, the step of determining that the electrode welding of the cell under test is abnormal if the voltage data of the voltage change curve changes by more than a preset value within a preset time period includes:

[0098] S520. If the voltage data of the voltage change curve during the constant current discharge stage increases by a value greater than the preset value within a preset time, it is determined that the electrode tab welding of the cell under test is abnormal.

[0099] It should be noted that the cell terminal voltage is sampled at 20-second intervals using a four-wire voltage sampling system (resolution ≤1mV). The data processing system uses an improved sliding window algorithm to calculate the voltage difference between adjacent sampling points. When the voltage rise within a single cycle exceeds a preset value, the electrode tab welding of the cell under test is determined to be abnormal.

[0100] In addition, the following criteria apply during the constant current discharge stage: If the voltage plateau period of the voltage curve is shortened by ≥15%, the electrode tab welding of the cell under test is deemed abnormal. During the constant current discharge stage, a normal cell will exhibit a relatively stable voltage plateau period due to the stable internal chemical reaction. When there is an electrode welding abnormality, the current conduction path is obstructed, and black spots of lithium plating appear in the cell, resulting in a relative reduction in capacity. Within the same charging time, the voltage rise of a cell with a smaller capacity is faster, causing the original plateau period to end prematurely, resulting in a shorter plateau period compared to a normal cell.

[0101] The working principle of this application is as follows:

[0102] Multiple battery cells to be tested are connected in parallel in the circuit. A constant current module is connected to the circuit to ensure a current accuracy of ±20mA. A constant voltage module is also connected to the circuit, enabling the circuit to charge the battery cells in constant voltage mode. In constant voltage mode, I = (U1 - U2) / (R1 + R2). Where U1 is the power supply voltage, U2 is the battery voltage, R1 is the loop impedance, and R2 is the battery internal resistance. As the charge (U1) gradually saturates, the battery internal resistance gradually increases (R2), the current (I) gradually decreases, and the voltage change gradually slows down. This stage is more conducive to detecting subtle voltage changes.

[0103] The battery cell is charged with a constant current of 0.1C-0.5C and then discharged with a constant current. The charge / discharge cutoff voltage is 4.2V and the discharge cutoff voltage is 2.8V.

[0104] Using a four-wire Kelvin connection, the voltage at the terminals of multiple battery cells is collected in real time, with a sampling interval of ≤30 seconds.

[0105] Based on the collected terminal voltages of multiple battery cells, the characteristics of the voltage curve are dynamically analyzed.

[0106] Example 1

[0107] Step 1: Let the battery cell to be tested rest for 1 minute.

[0108] Step 2: Constant current charging of the cell under test, with a charging current of 7300mA (0.1C) and a charging voltage of 4000mV, for a charging time of 600min. When the charging current reaches 735mA, the charging process is stopped.

[0109] Step 3: Let the battery cell to be tested rest for 5 minutes.

[0110] Step 4: Collect voltage data using a four-wire system, recording it every 20 seconds.

[0111] Step 5: During charging in Step 2, the voltage was detected to drop sharply from 3886mV to 3875mV (Δ=11mV), indicating a voltage mutation.

[0112] Step 6: Disassembly and verification showed that the base of the battery cell tab was broken.

[0113] Example 2

[0114] Step 1: Let the battery cell to be tested rest for 1 minute.

[0115] Step 2: Charge the battery cell under test with constant current and constant voltage. The charging current provided is 24333mA (0.33C), the charging voltage is 4200mV, and the charging time is 270min. Stop the charging process when the charging current is 3650mA.

[0116] Step 3: Let the battery cell to be tested rest for 5 minutes.

[0117] Step 4: Constant current discharge of the cell under test, with a charging current of 24333mA (0.33C), a charging voltage of 2750mV, and a charging time of 210min.

[0118] Step 5: Let the battery cell to be tested rest for 5 minutes.

[0119] Step 6: Charge the battery cell under test with constant current and constant voltage. The charging current provided is 24333mA (0.33C), the charging voltage is 3580mV, and the charging time is 180min. Stop the charging process when the charging current is 100mA.

[0120] Step 7: Let the battery cell to be tested rest for 5 minutes.

[0121] Step 8: Collect voltage data using a four-wire system, recording it every 30 seconds.

[0122] Step 9: In step 4, the voltage was detected to rise from 3578mV to 3591mV (Δ=13mV), which was determined to be a voltage sudden change.

[0123] Step 10: Perform DC internal resistance detection on the same abnormal cell (pulse current 1C, duration 10S). Discharge DCIR: 1.21mΩ (standard value: 1.16-1.37mΩ), judged as normal.

[0124] Step 11: Disassembly and verification revealed localized weld cracks in the first layer of the battery cell's tabs.

[0125] In another embodiment, a detection system for abnormal cell tab welding performs the above-described method for detecting abnormal cell tab welding. The detection system includes:

[0126] Parallel module, used to connect multiple cells to be tested in parallel.

[0127] The constant current charge / discharge module is used to perform constant current charging and constant current discharging on the battery cell under test.

[0128] The data acquisition module is used to acquire voltage data of the battery cell under test.

[0129] A module is established to create a voltage change curve for the battery cell under test based on the collected voltage data.

[0130] The judgment module is used to determine that the electrode welding of the battery cell under test is abnormal if the change value of the voltage data of the voltage change curve within a preset time is greater than a preset value.

[0131] In another embodiment, a computer-readable storage medium stores a computer program that, when executed by a computer processor, implements the above-described method for detecting abnormal cell tab welding.

[0132] The computer-readable storage medium in this embodiment can be a computer-readable signal medium, a computer-readable storage medium, or any combination thereof. For example, a computer-readable storage medium can be an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of a computer-readable storage medium may include, but are not limited to: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof. In this embodiment, the computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device. In this embodiment, a computer-readable signal medium can include a data signal propagated in baseband or as part of a carrier wave, carrying computer-readable program code. Such propagated data signals can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. Computer-readable signal media can also be any computer-readable storage medium other than a computer-readable storage medium, which can send, propagate, or transmit a program for use by or in connection with an instruction execution system, apparatus, or device. The program code contained on the computer-readable storage medium can be transmitted using any suitable medium, including but not limited to: wireless, wire, optical fiber, RF, etc., or any suitable combination thereof.

[0133] In another embodiment, a computer device performs the above-described method for detecting abnormal cell tab welding.

[0134] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method of detecting abnormality in welding of an electrode tab of an electric cell, characterized by, The method comprises the following steps: parallel connection of a plurality of battery cells to be detected; constant current charging and constant current discharging of the battery cells to be detected; collection of voltage data of the battery cells to be detected; establishment of a voltage change curve of the battery cells to be detected according to the collected voltage data of the battery cells to be detected; determination of abnormal tab welding of the battery cells to be detected if the voltage data of the voltage change curve changes by more than a preset value within a preset time.

2. The detection method according to claim 1, characterized in that, The step of constant current charging and constant current discharging of the battery cells to be detected further comprises: constant current charging of the battery cells to be detected; switching to a constant voltage charging mode when the voltage of the battery cells to be detected reaches a first preset voltage; stopping the charging process when the current in the constant voltage charging mode reaches a first preset current; constant current discharging of the battery cells to be detected; stopping the discharging process when the voltage of the battery cells to be detected reaches a second preset voltage.

3. The detection method according to claim 2, characterized in that, The step of stopping the discharging process when the voltage of the battery cells to be detected reaches a second preset voltage further comprises: constant current charging of the battery cells to be detected; switching to a constant voltage charging mode when the voltage of the battery cells to be detected reaches a third preset voltage; stopping the charging process when the current in the constant voltage charging mode reaches a second preset current; wherein the third preset voltage is less than the first preset voltage.

4. The detection method according to claim 2, characterized in that, The first preset voltage is 4-4.2 V; and / or The second preset voltage is 2.8-3 V.

5. The method of claim 1, wherein The step of determining abnormal tab welding of the battery cells to be detected if the voltage data of the voltage change curve changes by more than a preset value within a preset time comprises: determination of abnormal tab welding of the battery cells to be detected if the voltage data of the voltage change curve decreases by more than a preset value within a preset time in the constant current charging stage.

6. The method of claim 1, wherein The step of determining abnormal tab welding of the battery cells to be detected if the voltage data of the voltage change curve changes by more than a preset value within a preset time comprises: determination of abnormal tab welding of the battery cells to be detected if the voltage data of the voltage change curve increases by more than a preset value within a preset time in the constant current discharging stage.

7. The method of claim 1, wherein, The constant current charging of the battery cells to be detected is performed at a current rate of 0.1C-0.5C; and / or The constant current discharging of the battery cells to be detected is performed at a current rate of 0.1C-0.5C.

8. The method of claim 1, wherein, The preset value is 5-10 mV.

9. The method of claim 1, wherein, The voltage data of the battery cells to be detected is collected by a four-wire voltage sampling method.

10. A detection system for abnormal welding of battery cell tabs, characterized in that, The method comprises: a parallel connection module for parallel connection of a plurality of battery cells to be detected; a constant current charging and discharging module for constant current charging and constant current discharging of the battery cells to be detected; a collection module for collection of voltage data of the battery cells to be detected; an establishment module for establishment of a voltage change curve of the battery cells to be detected according to the collected voltage data of the battery cells to be detected; a determination module for determination of abnormal tab welding of the battery cells to be detected if the voltage data of the voltage change curve changes by more than a preset value within a preset time.

11. A computer readable storage medium having stored thereon a computer program, characterized in that, A computer program is executed by a computer processor to implement the method for detection of abnormal tab welding of battery cells according to any one of claims 1-9.

12. A computer device, comprising: The method for detecting abnormality in the electrode tab welding of the battery cell according to any one of claims 1 to 9 is executed.

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