A method and device for imaging multiple types of defects of a busbar-free cell

Abstract

The present invention provides a method and device for imaging multiple types of defects of a busbar-free cell. The method comprises the following steps: obtaining a photoluminescence image of the cell; extracting the grayscale information of the photoluminescence image, and extracting the first pixel row with the highest grayscale value based on the grayscale information; obtaining and splicing the first pixel row in all photoluminescence images according to the position information of the first pixel row to generate a first image; further determining the position information of the second pixel row according to the position information of the first pixel row, and splicing the second pixel row in all photoluminescence images to generate a second image. The first image mainly shows the structural defects of the cell, while the second image shows the resistive defects. The present invention reduces the need for manual intervention through automated operation, and can handle different types of defects on the cell, and is suitable for defect detection of busbar-free or low-busbar cells.

Description

Technical Field

[0001] The invention relates to a method and device for imaging multiple types of defects of a main grid-free battery cell. Background Art

[0002] Photoluminescence (PL) is a luminescence phenomenon of semiconductor materials. It refers to the process in which electrons in semiconductors are excited after absorbing external photons. The excited electrons are unstable and can transition to lower energy levels, releasing energy in the form of light radiation.

[0003] In the prior art, cell inspection is performed based on photoluminescence images, wherein a near-infrared camera can be used to capture photoluminescence images. The intact area of ​​the cell appears bright white, while the defective part appears as an obvious dark spot. Therefore, internal defects of the cell can be detected through the captured photoluminescence images.

[0004] Although this method can detect defects in battery cells, these defects still need to be identified manually. Since the number of photoluminescence images of a battery cell can be as high as hundreds, the detection efficiency is low. Therefore, how to simplify this manual adjustment method remains a problem. Summary of the invention

[0005] The purpose of the present invention is to solve the above shortcomings of the prior art and provide a method and device for imaging multiple types of defects of a busbar-free cell, aiming to reduce the number of hundreds of images to a smaller range, thereby reducing the manual workload of defect detection. The following is a specific solution:

[0006] In one aspect, the present invention provides a method for imaging multiple types of defects of a busbar-less cell, comprising the following steps: acquiring a photoluminescence image of the cell; acquiring grayscale information of the photoluminescence image; extracting a first pixel row with the highest grayscale value in the grayscale information based on the grayscale information; acquiring a first pixel row in each photoluminescence image based on position information of the first pixel row, and splicing images of the first pixel row to obtain a first image; determining position information of a second pixel row based on the position information of the first pixel row; acquiring a second pixel row in each photoluminescence image based on the position information of the second pixel row, and splicing images of the second pixel row to obtain a second image.

[0007] Furthermore, the obtaining of the photoluminescence image of the cell includes: obtaining 200-600 photoluminescence images according to the size of the cell.

[0008] Furthermore, the acquiring the grayscale information of the photoluminescence image includes: performing grayscale processing on each photoluminescence image to obtain the grayscale information of the photoluminescence image after the grayscale processing.

[0009] Furthermore, extracting the first pixel row with the highest grayscale value in the grayscale information according to the grayscale information includes: performing brightness calculation processing on the grayscale information in the photoluminescent image to obtain the grayscale information of the photoluminescent image after the brightness calculation processing, obtaining the pixel point with the highest grayscale value according to the grayscale information, and confirming the position of the first pixel row according to the pixel point with the highest grayscale value, wherein the length of the first pixel row is consistent with the length of the photoluminescent image, and the width of the first pixel row is 1-5 pixels.

[0010] Furthermore, the step of obtaining the first pixel row in each photoluminescent image based on the position information of the first pixel row and stitching the images of the first pixel row to obtain the first image includes: confirming the position information of the first pixel row on the x-axis and the y-axis in the photoluminescent image, extracting the first pixel row in other photoluminescent images based on the position information, and stitching the first pixel rows in all the photoluminescent images in sequence to obtain the first image.

[0011] Furthermore, determining the position information of the second pixel row according to the position information of the first pixel row includes: based on the position information of the first pixel row, confirming the position information of the second pixel row after deviating by 20-30 pixel rows.

[0012] Furthermore, the step of confirming the position information of the second pixel row after deviating from the position information of the first pixel row by 20-30 pixel rows includes: confirming the position information of the second pixel row after deviating from the position information of the first pixel row by a model algorithm by 20-30 pixel rows.

[0013] Furthermore, the model algorithm is trained based on the following steps: obtaining grayscale information of the photoluminescence image of the cell; extracting pixels with grayscale values ​​ranked 3-6 to obtain a third pixel row; and obtaining the model algorithm by comparing the position information of the third pixel row with the position information of the first pixel row.

[0014] Furthermore, the step of acquiring the second pixel row in each photoluminescent image based on the position information of the second pixel row and stitching the images of the second pixel row to obtain the second image includes: confirming the position information of the second pixel row on the x-axis and the y-axis in the photoluminescent image, extracting the second pixel row in other photoluminescent images based on the position information, and stitching the second pixel rows in all the photoluminescent images in sequence to obtain the second image.

[0015] On the other hand, the present invention provides a multi-type defect imaging device for a busbar-free cell, comprising: a shooting module, used to obtain a photoluminescence image of the cell; a grayscale acquisition module, used to obtain grayscale information of the photoluminescence image; an extraction module, used to extract a first pixel row with the highest grayscale value in the grayscale information according to the grayscale information, and also used to determine the position information of the second pixel row according to the position information of the first pixel row; a splicing module, used to obtain the first pixel row in each photoluminescence image according to the position information of the first pixel row, and splice the images of the first pixel row to obtain the first image, and also used to obtain the second pixel row in each photoluminescence image according to the position information of the second pixel row, and splice the images of the second pixel row to obtain the second image.

[0016] Compared with the prior art, the beneficial effects of the present invention are: through grayscale information extraction and pixel row stitching, the range of the detection image is reduced from the traditional 200-600 images to 2 images, which greatly reduces the detection difficulty and time cost, and improves the convenience and accuracy of defect detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic flow chart of a method for imaging multiple types of defects of a busbar-less cell;

[0018] Figure 2 The present invention is a schematic structural diagram of a multi-type defect imaging device for a main grid-free cell. DETAILED DESCRIPTION

[0019] In order to deepen the understanding of the present invention, the present invention will be further described in detail below in conjunction with embodiments and drawings. The embodiments are only used to explain the present invention and do not constitute a limitation on the protection scope of the present invention.

[0020] Figure 1 It is a schematic flow chart of a multi-type defect imaging method for a busbar-free cell provided by the present invention, comprising the following steps: Step 11: acquiring a photoluminescence image of the cell;

[0021] It should be noted that the length and width of the cell are not fixed, and the number of photoluminescent images of the cell depends on the length of the image. The photoluminescent images of the cell are obtained by a shooting device, which is composed of three parts: a conveyor belt, a camera and a light source.

[0022] In this embodiment, the battery cell is a battery cell without a main grid or with few main grids. The defects of this battery cell are less obvious than those of a battery cell with multiple main grids.

[0023] Step 12: Obtaining grayscale information of the photoluminescence image;

[0024] It should be noted that the photoluminescence image is grayed to obtain a two-dimensional gray matrix with pixel values ​​between 0 and 255. The two-dimensional gray matrix is ​​gray information.

[0025] Step 13: extracting the first pixel row with the highest grayscale value in the grayscale information according to the grayscale information;

[0026] It should be noted that the first pixel row has a width of 1-5 and a length that is the same as the length of the photoluminescence image. The first pixel row is actually a portion extracted from the photoluminescence image. In addition, the portion with the highest grayscale in the photoluminescence image of the cell, that is, the darker portion, represents that this portion does not have photoluminescence, and further indicates that this portion has a defect.

[0027] Specifically, according to the above-mentioned two-dimensional grayscale matrix, the pixel with the highest grayscale value is identified, and then the pixel is included in the first pixel row. The width of the first pixel row is determined according to whether the pixel with the highest grayscale value has more high grayscale values. For example, if there are continuous pixels with grayscale values ​​of 100, 140 or 200 around the pixel with a grayscale value of 240, these pixels will be included in the first pixel row at the same time.

[0028] Step 14: acquiring the first pixel row in each photoluminescence image according to the position information of the first pixel row, and splicing the images of the first pixel row to obtain the first image;

[0029] It should be noted that the first image is a conventional defect image, such as a broken gate.

[0030] Specifically, the position information of the first pixel row in the image is determined by step 13. After the position is determined, the position information is applied to each photoluminescence image to obtain images of the first pixel rows with the same number as the photoluminescence image. These images are then spliced ​​in the order in which the images are taken, thereby generating a more intuitive conventional defect map, which can better identify defects.

[0031] Step 15: Determine the position information of the second pixel row according to the position information of the first pixel row;

[0032] Specifically, based on the position information of the first pixel row, the x coordinate and the y coordinate of the first pixel row are obtained, and the position information of the second pixel row is determined based on the position of the center of the first pixel row.

[0033] Step 16: According to the position information of the second pixel row, the second pixel row in each photoluminescence image is obtained, and the images of the second pixel row are spliced ​​to obtain a second image.

[0034] It should be noted that the second image is a resistance defect image.

[0035] Specifically, the position information of the first pixel row in the image is determined by step 15. After the position is determined, the position information is applied to each photoluminescence image to obtain an image of the second pixel row with the same number as the photoluminescence image. These images are then spliced ​​in the order in which the images are taken, thereby generating a more intuitive resistance defect map, which can better identify defects.

[0036] The embodiment of the present invention realizes the production of an overall intuitive image of defects in the photoluminescence image of the cell through the above-mentioned solution, which makes it convenient for workers to observe the defects.

[0037] In one embodiment of the present invention, acquiring the photoluminescence image of the cell includes: taking 200-600 photoluminescence images according to the size of the cell, so as to further increase the adaptability to longer cells.

[0038] In one embodiment of the present invention, acquiring the grayscale information of the photoluminescence image includes: performing grayscale processing on each photoluminescence image to obtain the grayscale information of the grayscale processed photoluminescence image.

[0039] In one embodiment of the present invention, based on the grayscale information, extracting the first pixel row with the highest grayscale value in the grayscale information includes: performing brightness calculation processing on the grayscale information in the photoluminescent image, obtaining the grayscale information of the photoluminescent image after the brightness calculation processing, obtaining the pixel point with the highest grayscale value based on the grayscale information, and confirming the position of the first pixel row based on the pixel point with the highest grayscale value, wherein the length of the first pixel row is consistent with the length of the photoluminescent image, and the width of the first pixel row is 1-5 pixels, thereby further increasing the accuracy of identifying the first pixel row.

[0040] In one embodiment of the present invention, according to the position information of the first pixel row, the first pixel row in each photoluminescent image is obtained, and the images of the first pixel row are spliced ​​to obtain the first image, which includes: confirming the position information of the first pixel row on the x-axis and the y-axis in the photoluminescent image, extracting the first pixel row in other photoluminescent images based on the position information, and splicing the first pixel rows in all the photoluminescent images in sequence to obtain the first image, thereby further increasing the accuracy of identifying the first pixel row.

[0041] In one embodiment of the present invention, determining the position information of the second pixel row based on the position information of the first pixel row includes: based on the position information of the first pixel row, confirming the position information of the second pixel row after deviating from 20-30 pixel rows, thereby further increasing the accuracy of identifying the second pixel row.

[0042] In one embodiment of the present invention, based on the position information of the first pixel row, confirming the position information of the second pixel row after deviating from the first pixel row by 20-30 pixel rows includes: based on the position information of the first pixel row, confirming the position information of the second pixel row after deviating from the first pixel row by 20-30 pixel rows through a model algorithm, thereby further increasing the accuracy of identifying the second pixel row.

[0043] In one embodiment of the present invention, the model algorithm is trained based on the following steps: obtaining the grayscale information of the photoluminescence image of the cell; extracting pixels with grayscale values ​​ranked from 3 to 6 to obtain a third pixel row; and obtaining the model algorithm by comparing the position information of the third pixel row with the position information of the first pixel row to further increase the accuracy of identifying the second pixel row.

[0044] In one embodiment of the present invention, according to the position information of the second pixel row, the second pixel row in each photoluminescent image is obtained, and the images of the second pixel row are spliced ​​to obtain the second image, which includes: confirming the position information of the second pixel row on the x-axis and the y-axis in the photoluminescent image, extracting the second pixel row in other photoluminescent images based on the position information, and splicing the second pixel rows in all photoluminescent images in sequence to obtain the second image, thereby further increasing the accuracy of identifying the second pixel row.

[0045] Figure 2 It is a schematic diagram of the structure of a multi-type defect imaging device for a busbar-free cell. Figure 2 As shown, an embodiment of the present invention further provides a multi-type defect imaging device for a busbar-free cell, comprising: a shooting module 22, used to obtain a photoluminescence image of the cell; a grayscale acquisition module 33, used to obtain grayscale information of the photoluminescence image; an extraction module 44, used to extract a first pixel row with the highest grayscale value in the grayscale information according to the grayscale information, and also used to determine the position information of the second pixel row according to the position information of the first pixel row; a splicing module 55, used to obtain the first pixel row in each photoluminescence image according to the position information of the first pixel row, and splice the images of the first pixel row to obtain the first image, and also used to obtain the second pixel row in each photoluminescence image according to the position information of the second pixel row, and splice the images of the second pixel row to obtain the second image.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A method for imaging multiple types of defects of a busbar-less cell, characterized in that: The following steps are involved: Acquire a photoluminescent image of a cell; acquire grayscale information of the photoluminescent image; extract a first pixel row with the highest grayscale value in the grayscale information according to the grayscale information; acquire a first pixel row in each photoluminescent image according to position information of the first pixel row, and splice the images of the first pixel row to obtain a first image; determine position information of a second pixel row according to the position information of the first pixel row; According to the position information of the second pixel row, the second pixel row in each photoluminescent image is acquired, and the images of the second pixel row are spliced ​​to obtain a second image.

2. The method for imaging multiple types of defects of a busbar-less cell according to claim 1, characterized in that: The obtaining of the photoluminescence image of the cell comprises: obtaining 200-600 photoluminescence images according to the size of the cell.

3. The method for imaging multiple types of defects of a busbar-less cell according to claim 1, characterized in that: The acquiring the grayscale information of the photoluminescence image includes: performing grayscale processing on each photoluminescence image to obtain the grayscale information of the photoluminescence image after the grayscale processing.

4. The method for imaging multiple types of defects of a busbar-less cell according to claim 1, characterized in that: The extracting, according to the grayscale information, the first pixel row with the highest grayscale value in the grayscale information comprises: performing brightness calculation processing on the grayscale information in the photoluminescent image, obtaining the grayscale information of the photoluminescent image after the brightness calculation processing, obtaining the pixel point with the highest grayscale value according to the grayscale information, and confirming the position of the first pixel row according to the pixel point with the highest grayscale value, wherein the length of the first pixel row is consistent with the length of the photoluminescent image, and the width of the first pixel row is 1-5 pixels.

5. The method for imaging multiple types of defects of a busbar-less cell according to claim 1, characterized in that: The step of acquiring the first pixel row in each photoluminescent image according to the position information of the first pixel row and splicing the images of the first pixel row to obtain the first image comprises: confirming the position information of the first pixel row on the x-axis and the y-axis in the photoluminescent image, extracting the first pixel row in other photoluminescent images based on the position information, and splicing the first pixel rows in all the photoluminescent images in sequence to obtain the first image.

6. The method for imaging multiple types of defects of a busbar-less cell according to claim 1, characterized in that: Determining the position information of the second pixel row according to the position information of the first pixel row includes: based on the position information of the first pixel row, confirming the position information of the second pixel row after deviating by 20-30 pixel rows.

7. The method for imaging multiple types of defects of a busbar-less cell according to claim 6, characterized in that: The confirming the position information of the second pixel row after deviating from the position information of the first pixel row by 20-30 pixel rows includes: confirming the position information of the second pixel row after deviating from the position information of the first pixel row by a model algorithm by 20-30 pixel rows.

8. The method for imaging multiple types of defects of a busbar-less cell according to claim 7, characterized in that: The model algorithm is trained based on the following steps: obtaining grayscale information of the photoluminescence image of the cell; extracting pixels with grayscale values ​​ranked 3-6 to obtain the third pixel row; and obtaining the model algorithm by comparing the position information of the third pixel row with the position information of the first pixel row.

9. The method for imaging multiple types of defects of a busbar-less cell according to claim 1, characterized in that: The obtaining of the second pixel row in each photoluminescent image according to the position information of the second pixel row and splicing the images of the second pixel row to obtain the second image comprises: confirming the position information of the second pixel row on the x-axis and the y-axis in the photoluminescent image, extracting the second pixel row in other photoluminescent images based on the position information, and splicing the second pixel rows in all the photoluminescent images in sequence to obtain the second image.

10. A multi-type defect imaging device for a busbar-less cell, characterized in that: include: A shooting module, used to obtain a photoluminescence image of a cell; A grayscale acquisition module, used to acquire grayscale information of the photoluminescence image; an extraction module, configured to extract a first pixel row with the highest grayscale value in the grayscale information according to the grayscale information, and to determine position information of a second pixel row according to position information of the first pixel row; The splicing module is used to obtain the first pixel row in each photoluminescent image according to the position information of the first pixel row, and to splice the images of the first pixel row to obtain the first image. It is also used to obtain the second pixel row in each photoluminescent image according to the position information of the second pixel row, and to splice the images of the second pixel row to obtain the second image.

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