Method and system for detecting surface defects of composite falling and stacking battery cells

Abstract

The invention provides a composite falling and stacking cell surface defect detection method and system, and relates to the technical field of battery preparation, and the method comprises the steps: firstly obtaining real-time positioning information of a composite sheet at a feeding side, and then obtaining image information of the composite sheet in a falling and stacking process according to the real-time positioning information; the defect information of each pole piece on the composite sheet is obtained according to the image information, finally, the defect information of the multiple pole pieces of the same battery cell is gathered, and the unqualified battery cells are removed according to the defect information. Compared with the prior art, the composite falling and stacking cell surface defect detection method and system provided by the embodiment of the invention have the advantages that defect detection is completed in the falling and stacking stage, the image information is acquired by accurately monitoring the position of the composite sheet, and the defect information can be directly acquired through image information analysis; the stable and effective monitoring of the falling and stacking state of the battery cell is realized in the falling and stacking process, the defect information of the battery cell is accurately detected, the subsequent disassembly of the battery cell is avoided, and the battery cell material, manpower and material resources are saved.

Description

Technical Field

[0001] The present invention relates to the technical field of battery preparation, and in particular to a method and system for detecting surface defects of a composite stacked battery cell. Background Art

[0002] With the national support and popularization of new energy vehicles, the battery industry has also developed rapidly, and its production capacity and energy supply are growing rapidly. Lithium batteries have the advantages of high energy density, long service life, strong high and low temperature adaptability, and green environmental protection, making them the most widely used type of batteries.

[0003] In the current market of lithium battery stacking equipment, stacking machines are generally "traditional Z stacking" and "cutting and stacking machines". The stacking process is that a robot grabs the pole pieces and stacks the battery cells one by one on the stacking table. The whole stacking process is slow and the pole pieces are in a static state. These single machines have low efficiency, large footprint, high energy consumption, high operating costs, uneven stretching of the diaphragm, affecting battery life and consistency. At present, another stacking process has begun to appear in the stacking machines on the market - "hot composite stacking machine", and its stacking method can effectively solve the shortcomings of stacking in the current market.

[0004] However, it is different from other lamination machine process flows in that hot composite sheet lamination is a continuous lamination and lamination of electrode sheets and composite sheets, during the lamination process the composite sheets are also continuously stacked. As the diaphragm is continuous and the composite electrode sheets need to be rolled over multiple times, the production process may cause wrinkles and scratches on the unit sheets during the rolling process, affecting the quality of the battery cell.

[0005] In the prior art, for the hot composite lamination process, defect detection is not performed during the lamination stage. Therefore, if one wants to check whether there are wrinkles and scratches on the surface of the diaphragm before the battery cell is stacked, the battery cell needs to be disassembled and the condition of each unit cell needs to be checked. The consequence of this is a waste of battery cell materials and manpower and material resources. Summary of the invention

[0006] The objectives of the present invention include, for example, providing a method and system for detecting surface defects of a composite stacked battery cell, which can achieve stable and effective monitoring of the stacking state of the battery cells during the stacking process, accurately detect the defect information of the battery cells, avoid subsequent disassembly of the battery cells, and save battery cell materials and manpower and material resources.

[0007] The embodiments of the present invention can be implemented as follows:

[0008] In a first aspect, the present invention provides a method for detecting surface defects of a composite stacked battery cell, comprising:

[0009] Obtain real-time positioning information of the composite sheet on the feeding side;

[0010] Acquiring image information of the composite sheet during the stacking process according to the real-time positioning information, wherein the image information includes the pole pieces on the composite sheet;

[0011] Acquiring defect information of each pole piece on the composite sheet according to the image information;

[0012] The defect information of the multiple pole pieces of the same battery cell is summarized, and unqualified battery cells are eliminated based on the defect information of the multiple pole pieces.

[0013] In an optional embodiment, the step of obtaining the positioning information of the composite sheet on the feeding side includes:

[0014] Obtaining the position information of the blank area of ​​the composite sheet;

[0015] Obtaining speed information of the composite sheet;

[0016] The real-time positioning information of the composite sheet is calculated according to the position information and the speed information.

[0017] In an optional embodiment, the step of acquiring image information of the composite sheet during the stacking process according to the real-time positioning information includes:

[0018] Locating the center position of the pole piece on the composite sheet according to the real-time positioning information;

[0019] When the center position of the pole piece overlaps horizontally with the imaging center position of the imaging device, the imaging device is triggered to take a picture to obtain image information of the composite sheet in the stacking process.

[0020] In an optional embodiment, the step of obtaining defect information of each pole piece on the composite sheet according to the image information includes:

[0021] Extracting the pole piece detection area in the image information to obtain a pole piece area image;

[0022] Performing filtering processing on the pole piece detection area to obtain a pole piece filtered image;

[0023] Defect information of the pole piece detection area is obtained based on the difference between the pole piece area image and the pole piece filter image.

[0024] In an optional embodiment, the step of extracting the pole piece detection area in the image information includes:

[0025] Performing binarization processing on the image information;

[0026] Performing an opening operation on the binarized image information;

[0027] Obtain the current detection pole piece area through contour recognition;

[0028] The original image information is subjected to mask processing through the current detection pole piece area to complete the extraction of the pole piece detection area.

[0029] In an optional embodiment, before the step of extracting the pole piece detection area in the image information, the method further includes:

[0030] Get the battery cell code;

[0031] The coding of the battery cell is bound to the corresponding image information.

[0032] In an optional embodiment, after the step of obtaining defect information of the pole piece detection area according to the difference between the pole piece area image and the pole piece filtered image, the method further includes:

[0033] Blob analysis is performed on the defect information, and defect classification is performed.

[0034] In a second aspect, the present invention provides a composite stacked cell surface defect detection system, which is applicable to the composite stacked cell surface defect detection method as described in any one of the aforementioned embodiments, and the system comprises:

[0035] A stacking device, the stacking device is used to carry the composite sheets that are stacked;

[0036] A feeding detection device, which is arranged above the stacking device and is used to obtain real-time positioning information of the composite sheet on the feeding side;

[0037] An imaging device, the imaging device is arranged on both sides of the stacking device and is in communication connection with the feeding detection device, and is used to take pictures of the composite sheet in the stacking process according to the real-time positioning information, and obtain image information of the composite sheet in the stacking process, wherein the image information includes the pole pieces on the composite sheet;

[0038] A control device, the control device is simultaneously connected to the stacking device, the feeding detection device and the imaging device for obtaining defect information of each pole piece on the composite sheet according to the image information;

[0039] An industrial computer is communicatively connected with the control device, and is used to aggregate the defect information of multiple pole pieces of the same battery cell, and eliminate unqualified battery cells based on the defect information of multiple pole pieces.

[0040] In an optional embodiment, the feed detection device includes a feed roller group, a drive member and a sensor. The feed roller group is arranged above the stacking device, and is used to drive the composite sheet to fall toward the stacking device. The drive member is transmission-connected to the feed roller group, and is used to control the stacking speed of the composite sheet. The sensor is arranged above the feed roller group, and is used to sense the blank area of ​​the composite sheet and detect the stacking position of the composite sheet.

[0041] In an optional embodiment, the composite drop-stacked battery cell surface defect detection system further includes a visual light source disposed on both sides of the stacking device, wherein the visual light source is disposed on the upper side of the imaging device for illuminating the surface of the composite sheet.

[0042] In an optional embodiment, the imaging device includes an industrial camera and an area array lens, the area array lens is arranged on the framing side of the industrial camera, and the industrial camera is used to take pictures of the stacked composite sheets.

[0043] The beneficial effects of the embodiments of the present invention include, for example:

[0044] The surface defect detection method and system of composite stacked battery cells provided in the embodiments of the present invention first obtain the real-time positioning information of the composite sheet on the feeding side, then obtain the image information of the composite sheet during the stacking process based on the real-time positioning information, and obtain the defect information of each electrode sheet on the composite sheet based on the image information, and finally summarize the defect information of multiple electrode sheets of the same battery cell, and eliminate unqualified batteries according to the defect information. Compared with the prior art, the surface defect detection method and system of composite stacked battery cells provided in the embodiments of the present invention completes defect detection in the stacking stage, obtains image information by accurately monitoring the position of the composite sheet, and can directly obtain defect information through image information analysis, so as to realize stable and effective monitoring of the stacking state of the battery cells during the stacking process, accurately detect the defect information of the battery cells, avoid subsequent disassembly of the battery cells, and save battery cell materials and manpower and material resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0046] Figure 1 A structural block diagram of a composite drop-stack battery cell surface defect detection system provided by an embodiment of the present invention;

[0047] Figure 2A schematic diagram of the structure of a composite drop-stack battery cell surface defect detection system provided by an embodiment of the present invention;

[0048] Figure 3 for Figure 1 Control logic diagram of the control device;

[0049] Figure 4 A flowchart of the method for detecting surface defects of a composite stacked battery cell provided by an embodiment of the present invention;

[0050] Figure 5 for Figure 4 Execution logic diagram of step S3 in .

[0051] Icons: 100-composite stacked battery cell surface defect detection system; 110-stacking device; 120-feeding detection device; 121-feeding roller group; 123-driving part; 125-sensor; 130-imaging device; 140-control device; 150-industrial computer; 160-visual light source. DETAILED DESCRIPTION

[0052] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0053] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0054] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0055] In the description of the present invention, it should be noted that if the terms "upper", "lower", "inside", "outside", etc. appear to indicate an orientation or position relationship, they are based on the orientation or position relationship shown in the accompanying drawings, or are the orientation or position relationship in which the product of the invention is usually placed when used. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0056] In addition, the terms “first”, “second”, etc., if used, are merely used to distinguish between the descriptions and should not be understood as indicating or implying relative importance.

[0057] As disclosed in the background technology, in the prior art, defect detection is usually not performed in the stacking stage for the stacking machine process flow. The reason is that the stacking process is fast and it is difficult to quickly and accurately capture the image of the composite sheet using a conventional image acquisition device. Therefore, if you want to check whether there are wrinkles and scratches on the surface of the diaphragm before the battery cell is stacked, you need to disassemble the battery cell and check the condition of each unit cell. The consequence of doing so is a waste of battery cell materials and manpower and material resources.

[0058] In addition, due to the limited distance between the stacking device and the driving components above, the space is narrow, and conventional line array cameras have certain limitations in shooting, and the degree of freedom of line array cameras is not high. When the position is adjusted, a lot of time is required for debugging. At the same time, line array cameras are relatively expensive, resulting in high costs.

[0059] In order to solve the above problems, the present invention provides a novel composite stacked battery cell surface defect detection method and system. It should be noted that the features in the embodiments of the present invention can be combined with each other without conflict.

[0060] Please refer to Figure 1 and Figure 2 The embodiment of the present invention provides a method for detecting surface defects of a composite stacked battery cell, which is applicable to a composite stacked battery cell surface defect detection system 100, which can realize stable and effective monitoring of the stacking state of the battery cells during the stacking process, accurately detect the defect information of the battery cells, avoid subsequent disassembly of the battery cells, and save battery cell materials and manpower and material resources.

[0061] The composite stacked cell surface defect detection system 100 disclosed in the embodiment of the present invention comprises a stacking device 110, a feed detection device 120, an imaging device 130, a control device 140 and an industrial computer 150. The stacking device 110 is used to carry the stacked composite sheets; the feed detection device 120 is arranged above the stacking device 110, and is used to obtain the real-time positioning information of the composite sheets on the feed side; the imaging device 130 is arranged on both sides of the stacking device 110, and is connected to the feed detection device for communicating with the real-time positioning information of the composite sheets. The control device 140 is connected in communication with the stacking device 110, the material feeding detection device 120 and the imaging device 130 at the same time, and is used to obtain the defect information of each electrode on the composite sheet according to the image information; the industrial computer 150 is connected in communication with the control device 140, and is used to summarize the defect information of multiple electrodes of the same battery cell, and eliminate unqualified batteries according to the defect information of multiple electrodes.

[0062] During actual inspection, the feed detection device 120 is used to obtain real-time positioning information of the composite sheet on the feed side. The real-time positioning information can be transmitted to the control device 140 in time, and the control device 140 calculates the shooting position. The setting position of the imaging device 130 is relatively fixed to the setting position of the feed detection device 120. Therefore, after obtaining the real-time positioning information, the control device 140 can calculate the actual position movement trajectory of the composite sheet, and trigger the imaging device 130 when the pole piece on the composite sheet corresponds to the imaging device 130 to capture the real-time image of each falling composite sheet, thereby obtaining image information containing the pole piece, and then sending the image information to the image processing software in the control device 140 for processing, so that the control device 140 can obtain the defect information of each pole piece on the composite sheet based on the image information, and then summarize the defect information of the same battery cell and send it to the industrial computer 150. The industrial computer 150 can determine whether the battery cell is qualified, so as to propose unqualified batteries based on the defect information of multiple pole pieces.

[0063] Furthermore, the feed detection device 120 includes a feed roller group 121, a driving member 123 and a sensor 125. The feed roller group 121 is arranged above the stacking device 110, and is used to drive the composite sheet to fall toward the stacking device 110. The driving member 123 is connected to the feed roller group 121 in a transmission manner, and is used to control the stacking speed of the composite sheet. The sensor 125 is arranged above the feed roller group 121, and is used to sense the blank area of ​​the composite sheet and detect the stacking position of the composite sheet. Specifically, the driving member 123 can be a servo motor, and the feed roller group 121 is a double-roller structure and is driven by a servo motor. The servo motor and the sensor 125 respectively obtain the blank area position information and the stacking speed information of the composite sheet, and calculate the real-time position information and transmit it to the control device 140. The control device 140 determines the photographing time of the photographing device according to the real-time position information.

[0064] In this embodiment, the imaging device 130 includes an industrial camera and an array lens. The array lens is arranged on the viewfinder side of the industrial camera, and the industrial camera is used to take pictures of the stacked composite sheets. Specifically, the array lens can be used to take pictures of the composite sheets between the stacking device 110 and the feeding detection device 120. The detection efficiency is high, and the workshop space is not occupied. The cost is low. The abnormal defective cells in the production process of the cells can be quickly detected and the alarm is stopped for inspection, which greatly reduces the waste of continuous defective cells.

[0065] Furthermore, the composite stacked cell surface defect detection system 100 further includes visual light sources 160 disposed on both sides of the stacking device 110. The visual light sources 160 are disposed on the upper side of the imaging device 130 and are used to illuminate the surface of the composite sheet. Specifically, the visual light source 160 is set at a fixed inclination angle, and can illuminate the composite sheet in the stacked state, so that the imaging device 130 can capture images.

[0066] During actual detection, the control device 140 triggers the imaging device 130 to take a photo, and the imaging device 130 calls back the image data after being triggered; after receiving the image data, the software in the control device 140 immediately obtains the battery cell ID from the control device 140 and completes the binding of the battery cell ID and the image; then the acquired image is binarized, the background interference is removed by morphological opening operation, the current detection pole piece area is obtained by maximum area contour recognition, the original image is masked through the current calculation area, and the pole piece detection area is extracted; the extracted detection area original image is subjected to large kernel filtering to obtain a filtered and blurred image; the filtered image is subtracted from the original image to obtain a difference image, the difference image is binarized, and the defect information in the pole piece area is obtained, and defect classification is performed through Blob analysis (such as area, length, width, grayscale, etc.), and the detection data is saved and uploaded.

[0067] During the working process, the feed roller group 121 has a servo motor to drive the composite sheet to move; when the blank space on the composite sheet passes the sensor 125, the sensor 125 records the current blank space position and calculates the photo trigger position of the imaging device 130 according to the physical distance between the sensor 125 and the left and right camera photo positions; as the composite sheet continues to move downward, the control device 140 monitors the moving distance of the composite sheet material belt in real time, and when the trigger position condition is met, the signal triggers the imaging device 130 to take a photo; then the imaging device 130 sends the image data to the image processing software in the control device 140, and the surface defect information of the composite sheet is calculated through the image, and accumulated for one battery cell to obtain the defect information data of the battery cell. When the battery cell has defects such as wrinkles and scratches, it is transmitted to the industrial computer 150 through communication to realize data interaction and closed loop.

[0068] See also Figure 3, the working logic and principle of the control device 140 are further explained below: after starting the detection, the control device 140 can first calibrate the physical position of the imaging device 130 by external input, and then trigger the imaging device 130 to take pictures according to the real-time position information to obtain image information, and then analyze the image information through the built-in software algorithm to detect the surface defect information of the electrode, and then determine whether it is the last electrode of the same battery cell. If not, continue to trigger the imaging device 130 to take pictures; if it is the last piece, summarize the overall defect information of the same battery cell, if the battery cell meets the defect requirements, control the industrial computer 150 or unload, if not, control the battery cell to be discharged, that is, remove the waste battery cell. Of course, the determination of whether the battery cell meets the requirements here can also be directly determined by the industrial computer 150, or the control device 140 can be integrated in the industrial computer 150.

[0069] See also Figure 4 The method for detecting surface defects of a composite stacked cell provided by an embodiment of the present invention comprises the following steps:

[0070] S1: Obtaining real-time positioning information of the composite sheet on the feeding side.

[0071] Specifically, a feed detection device 120 is provided on the feed side, and the feed detection device 120 is provided above the stacking device 110, and can detect the real-time positioning information of the composite sheet on the feed side. In actual detection, the position information of the blank area of ​​the composite sheet can be first obtained, that is, the position of the blank area of ​​the composite sheet can be obtained by using the sensor 125, so as to determine the stacking position of the composite sheet; then the speed information of the composite sheet can be obtained, and the stacking speed of the composite sheet can be obtained by obtaining the parameters of the driving member 123.

[0072] S2: Acquire image information of the composite sheet during the stacking process based on the real-time positioning information.

[0073] The image information includes the pole piece on the composite sheet. The image information here can be obtained by taking a photo with the imaging device 130. The timing of taking a photo with the imaging device 130 can be determined by more real-time positioning information. Specifically, the center position of the pole piece on the composite sheet can be first located by the control device 140 according to the real-time positioning information; then the control device 140 is used to trigger the imaging device 130 to take a photo when the center position of the pole piece overlaps horizontally with the imaging center position of the imaging device 130, so as to obtain the image information of the composite sheet in the stacking process. The setting position of the imaging device 130 is relatively fixed to the setting position of the feeding detection device 120. Therefore, after obtaining the real-time positioning information, the actual position movement trajectory of the composite sheet can be calculated, and the pole piece on the composite sheet can be photographed when it corresponds to the imaging device 130, so as to obtain the image information including the pole piece.

[0074] It should be noted that the control device 140 here can accurately obtain the timing when the center of the electrode on the composite sheet overlaps with the imaging center of the imaging device 130 through calculation, and trigger the photo-taking action under this condition. Due to the particularity of the production process here, the positive electrode will be mounted on the left and right sides of the material strip, so the left and right imaging devices 130 can be used to take photos alternately, and the negative electrode is wrapped in the diaphragm, and the surface defects of the negative electrode can also be determined by the surface shape of the diaphragm. By continuously taking pictures, the image information of all the unit cells in the entire battery cell can be obtained.

[0075] S3: Obtain defect information of each pole piece on the composite sheet based on the image information.

[0076] Specifically, after the control device 140 obtains the image information, its internal processing software can first obtain the battery cell code; bind the battery cell code with the corresponding image information, and then extract the pole piece detection area in the image information to obtain the pole piece area image; then filter the pole piece detection area to obtain the pole piece filtered image; finally, obtain the defect information of the pole piece detection area based on the difference between the pole piece area image and the pole piece filtered image, and finally perform Blob analysis on the defect information and perform defect classification.

[0077] In actual processing, see Figure 5 After receiving the image information, the software in the control device 140 immediately obtains the battery cell ID from the control device 140 and completes the binding of the battery cell ID and the image; then the obtained image is binarized, the background interference is removed by morphological opening operation, the current detection pole area is obtained by maximum area contour recognition, the original image is masked through the current calculation area, and the pole detection area extraction is completed; the extracted detection area original image is subjected to large kernel filtering to obtain a filtered and blurred image; the filtered image is subtracted from the original image to obtain a difference image, the difference image is binarized, and the defect information in the pole area is obtained, and defect classification is performed through Blob analysis (such as area, length, width, grayscale, etc.), and the detection data is saved and uploaded.

[0078] S4: Summarize the defect information of multiple pole pieces of the same battery cell, and eliminate unqualified battery cells based on the defect information of multiple pole pieces.

[0079] Specifically, the control device 140 may also have a display screen, and the defect information may be displayed on the display screen after being summarized. At the same time, the industrial computer 150 may determine whether the defect information of multiple electrodes in the same battery cell meets the requirements, and if so, the electrode is cut normally, and if not, it is discarded.

[0080] The surface defect detection method and system of composite stacked battery cells provided in the embodiments of the present invention first obtain the real-time positioning information of the composite sheet on the feeding side, then obtain the image information of the composite sheet during the stacking process based on the real-time positioning information, and obtain the defect information of each electrode sheet on the composite sheet based on the image information, and finally summarize the defect information of multiple electrode sheets of the same battery cell, and eliminate unqualified batteries according to the defect information. Compared with the prior art, the surface defect detection method and system of composite stacked battery cells provided in the embodiments of the present invention completes defect detection in the stacking stage, obtains image information by accurately monitoring the position of the composite sheet, and can directly obtain defect information through image information analysis, so as to realize stable and effective monitoring of the stacking state of the battery cells during the stacking process, accurately detect the defect information of the battery cells, avoid subsequent disassembly of the battery cells, and save battery cell materials and manpower and material resources.

[0081] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for detecting surface defects of composite stacked cells. It is characterized in that include: Obtain real-time positioning information of the composite sheet on the feeding side; Acquiring image information of the composite sheet during the stacking process according to the real-time positioning information, wherein the image information includes the pole pieces on the composite sheet; Acquiring defect information of each pole piece on the composite sheet according to the image information; The defect information of the multiple pole pieces of the same battery cell is summarized, and unqualified battery cells are eliminated based on the defect information of the multiple pole pieces.

2. The method for detecting surface defects of a composite fall-stack battery cell according to claim 1, It is characterized in that The step of obtaining the real-time positioning information of the composite sheet at the feeding side includes: Obtaining the position information of the blank area of ​​the composite sheet; Obtaining speed information of the composite sheet; The real-time positioning information of the composite sheet is calculated according to the position information and the speed information.

3. The method for detecting surface defects of a composite fall-stack battery cell according to claim 1, It is characterized in that The step of acquiring image information of the composite sheet during the stacking process according to the real-time positioning information comprises: Locating the center position of the pole piece on the composite sheet according to the real-time positioning information; When the center position of the pole piece overlaps horizontally with the imaging center position of the imaging device, the imaging device is triggered to take a picture to obtain image information of the composite sheet in the stacking process.

4. The method for detecting surface defects of a composite fall-stack battery cell according to claim 1, It is characterized in that The step of obtaining defect information of each pole piece on the composite sheet according to the image information comprises: Extracting the pole piece detection area in the image information to obtain a pole piece area image; Performing filtering processing on the pole piece detection area to obtain a pole piece filtered image; Defect information of the pole piece detection area is obtained based on the difference between the pole piece area image and the pole piece filter image.

5. The method for detecting surface defects of a composite fall-stack battery cell according to claim 4, It is characterized in that Before the step of extracting the pole piece detection area in the image information, the method further includes: Get the battery cell code; The coding of the battery cell is bound to the corresponding image information.

6. The method for detecting surface defects of a composite fall-stack battery cell according to claim 4, It is characterized in that After the step of obtaining defect information of the pole piece detection area according to the difference between the pole piece area image and the pole piece filter image, the method further includes: Blob analysis is performed on the defect information, and defect classification is performed.

7. A composite drop-stack battery cell surface defect detection system, applicable to the composite drop-stack battery cell surface defect detection method according to any one of claims 1 to 6, It is characterized in that The system comprises: A stacking device, the stacking device is used to carry the composite sheets that are stacked; A feeding detection device, which is arranged above the stacking device and is used to detect real-time positioning information of the composite sheet on the feeding side; An imaging device, which is arranged on both sides of the stacking device and is in communication with the feeding detection device, and is used to take pictures of the composite sheet in the stacking process according to the real-time positioning information, and obtain image information of the composite sheet in the stacking process, wherein the image information includes the pole pieces on the composite sheet; A control device, the control device is simultaneously connected to the stacking device, the feeding detection device and the imaging device for obtaining defect information of each pole piece on the composite sheet according to the image information; An industrial computer is communicatively connected with the control device, and is used to aggregate the defect information of multiple pole pieces of the same battery cell, and eliminate unqualified battery cells based on the defect information of multiple pole pieces.

8. The composite drop-stack battery cell surface defect detection system according to claim 7, It is characterized in that The feed detection device includes a feed roller group, a driving member and a sensor. The feed roller group is arranged above the stacking device and is used to drive the composite sheet to fall toward the stacking device. The driving member is transmission-connected to the feed roller group and is used to control the stacking speed of the composite sheet. The sensor is arranged above the feed roller group and is used to sense the blank area of ​​the composite sheet and detect the stacking position of the composite sheet.

9. The composite drop-stack battery cell surface defect detection system according to claim 7, It is characterized in that The composite drop-stacked battery cell surface defect detection system also includes visual light sources arranged on both sides of the stacking device, and the visual light sources are arranged on the upper side of the imaging device to illuminate the surface of the composite sheet.

10. The composite drop-stack battery cell surface defect detection system according to claim 7, It is characterized in that The imaging device comprises an industrial camera and an area array lens, wherein the area array lens is arranged on the viewfinder side of the industrial camera, and the industrial camera is used to take pictures of the stacked composite sheets.

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