A method and device for detecting defects in a battery steel shell

Abstract

The present invention discloses a method and device for detecting defects in battery steel shells. The method involves inserting a columnar power source into the battery steel shell to allow light to pass through the battery steel shell, then using an image device to collect the image, and performing binary processing and recognition on the image to achieve fully automatic detection of sand holes and other defects in the battery steel shell, preventing battery steel shells with defects such as sand holes and air holes from flowing into the next process, realizing automatic detection of defects in battery steel shells, and greatly reducing the quality risks brought by defects in battery steel shells. The device provided by the present invention includes: a columnar light source, a telescopic device, a rotating device, an image acquisition device, and a control device, which can automatically implement the above detection method and improve the detection efficiency.

Description

Technical Field

[0001] The present invention relates to a battery detection method, and more specifically, to a method and device for detecting defects in a battery steel shell. Background Art

[0002] The battery steel shell is an important quality control point of the battery. If there are defects such as sand holes and air holes in the battery steel shell, it will cause battery leakage, and the leakage of one battery may cause a batch of batteries to be scrapped, resulting in huge losses. The reasons for the generation of sand holes and air holes in the battery steel shell may be: surface defects of the steel plate, steel inclusions, and improper maintenance of the user's mold and nickel plating operation in the subsequent process (mainly for pre-nickel plating). The sand holes and air holes in the steel shell are manifested on the surface of the steel shell as defects with U-shaped, crescent-shaped closed or open morphologies on the steel shell.

[0003] Currently, there is no technical solution in the industry to achieve fully automatic detection of sand hole defects in battery steel shells by machines. Moreover, due to the huge daily production volume of batteries, it is impossible for manual inspection to cover the entire surface of the battery steel shell, and a random sampling method is adopted for inspection. Summary of the Invention

[0004] The present invention overcomes the deficiencies of the prior art and provides a method and device for detecting defects in a battery steel shell, in order to hopefully solve the above problems.

[0005] To solve the above technical problems, the present invention provides a method for detecting defects in a battery steel shell, including the following steps:

[0006] S1: Control the ambient brightness not to be higher than 150 lx. The control device controls the cylindrical light source to extend into the battery steel shell, and the control device controls the image acquisition device to collect the surface image of the battery steel shell.

[0007] S2: The control device controls the rotating device to rotate the battery steel shell, and controls the image acquisition device to collect the surface image of the rotating battery steel shell to obtain a complete image of the surface of the battery steel shell.

[0008] S3: The control device performs gray-scale processing on the obtained image to obtain a gray-scale image, and the control device performs binary processing on the obtained gray-scale image to obtain a binary image.

[0009] S4: The control device identifies the binary image to confirm whether there is a light spot on the image. If there is a light spot, it is determined that there is a defect on the battery steel shell; if there is no light spot, it is determined that there is no defect on the battery steel shell.

[0010] Since it is difficult for the image acquisition device to collect the light spot on the surface of the battery steel shell to be measured in a high-brightness environment, it is necessary to control the ambient brightness.

[0011] Due to defects such as trachoma and air holes, when lighting from the inside, light will penetrate through the surface of the battery steel shell, forming light spots. By processing the image and identifying the light spots, it is possible to determine whether there are defects such as trachoma and air holes on the surface of the battery steel shell, thus realizing the automatic detection of defects in the battery steel shell.

[0012] A further technical solution is: in S3, the binaryzation process is specifically: using the Otsu algorithm;

[0013] Due to possible fluctuations in environmental illuminance, the threshold value obtained using the Otsu algorithm can better distinguish the light spots from the surface.

[0014] An even further technical solution is: in S1, the environmental brightness is controlled below 50 lx;

[0015] In S3, the binaryzation process is specifically: the global threshold method;

[0016] When the environmental brightness is lower than 50 lx, the contrast between the light spots and the surface on the battery steel shell is relatively large, and the global threshold method can be used to better complete the image binaryzation process.

[0017] An even further technical solution is: the specific method of S2 is:

[0018] The control device controls the image acquisition device to acquire an image of the battery steel shell. After the first acquisition is completed, the control device controls the rotation device to rotate the battery steel shell by 120°. When the rotation is completed, the control device controls the image acquisition device to acquire an image of the battery steel shell again. After the second acquisition is completed, the control device controls the rotation device to rotate the battery steel shell by 120°, and the control device controls the image acquisition device to perform a final image acquisition of the battery steel shell. A complete image of the surface of the battery steel shell is obtained through 3 acquisitions;

[0019] The present invention also provides a device for detecting defects in a battery steel shell, including: a cylindrical light source, a telescopic device, a rotation device, an image acquisition device, and a control device;

[0020] The cylindrical light source is installed on the telescopic device;

[0021] The rotation device is in contact with the battery steel shell to be tested;

[0022] The telescopic device, the image acquisition device, and the rotation device are connected to the control device.

[0023] A further technical solution is: the cylindrical light source has the same length as the battery steel shell to be tested.

[0024] An even further technical solution is: the rotation device includes: a roller and a driving device;

[0025] The roller is in contact with the battery steel shell to be tested;

[0026] The driving device drives the roller to rotate.

[0027] Compared with the prior art, the present invention has at least the following beneficial effects: by inserting a columnar power source into the battery steel shell, the present invention allows light to pass through the battery steel shell, then uses an image device to collect the image, and performs binarization processing and recognition on the image, realizing full-automatic detection of sand holes and other defects in the battery steel shell, preventing battery steel shells with defects such as sand holes and air holes from flowing into the next process, achieving automatic detection of battery steel shell defects, and greatly reducing the quality risks brought by battery steel shell defects. Description of the Drawings

[0028] Figure 1 It is a schematic flow chart of a method for detecting defects in a battery steel shell provided by the present invention.

[0029] Figure 2 It is a schematic overall structure diagram of a device for detecting defects in a battery steel shell provided by the present invention.

[0030] In the figure: a device for detecting defects in a battery steel shell, including: a columnar light source 1, a telescopic device 2, a rotating device 3, an image acquisition device 4, and a control device 5; Detailed Embodiments

[0031] In order to make the objectives, technical solutions and advantages of the present invention clearer, the following further describes the present invention in detail with reference to embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0032] Embodiment 1: A method for detecting defects in a battery steel shell, as Figure 1 shown, includes the following steps;

[0033] S101: Control the ambient brightness not to be higher than 150 lx. The control device controls the columnar light source to extend into the battery steel shell, and the control device controls the image acquisition device to collect the surface image of the battery steel shell;

[0034] S102: The control device controls the image acquisition device to collect an image of the battery steel shell. After the first collection is completed, the control device controls the rotating device to rotate the battery steel shell by 120°. When the rotation is completed, the control device controls the image acquisition device to collect the image of the battery steel shell again. After the second collection is completed, the control device controls the rotating device to rotate the battery steel shell by 120°, and the control device controls the image acquisition device to perform a final image collection on the battery steel shell. A complete image of the surface of the battery steel shell is obtained through three collections;

[0035] S103: The control device performs grayscale processing on the acquired image to obtain a grayscale image, and the control device performs binarization processing on the obtained grayscale image using the Otsu algorithm to obtain a binary image;

[0036] S104: The control device identifies the binary image to confirm whether there is a light spot on the image. If there is a light spot, it is determined that there is a defect on the battery steel shell; if there is no light spot, it is determined that there is no defect on the battery steel shell.

[0037] Embodiment 2: A method for detecting defects on a battery steel shell, including the following steps;

[0038] S201: Control the ambient brightness not to be higher than 50 lx. The control device controls the cylindrical light source to extend into the battery steel shell, and the control device controls the image acquisition device to collect the surface image of the battery steel shell;

[0039] S202: The control device controls the image acquisition device to collect an image of the battery steel shell. After the collection starts, the control device controls the rotating device to rotate the battery steel shell to be measured until the battery steel shell to be measured rotates one week, and then the collection ends. The image acquisition device sends the collected signal to the control device, and the control device processes the collected signal to obtain a complete image of the surface of the battery steel shell;

[0040] S203: The control device performs grayscale processing on the acquired image to obtain a grayscale image, and the control device performs binarization processing on the obtained grayscale image using the global threshold method to obtain a binary image;

[0041] S204: The control device identifies the binary image to confirm whether there is a light spot on the image. If there is a light spot, it is determined that there is a defect on the battery steel shell; if there is no light spot, it is determined that there is no defect on the battery steel shell.

[0042] Embodiment 3: An apparatus for detecting defects on a battery steel shell, as Figure 2 shown, includes: a cylindrical light source 1, a telescopic device 2, a rotating device 3, an image acquisition device 4, and a control device 5;

[0043] The cylindrical light source 1 is the same length as the battery steel shell to be measured and is installed on the telescopic device 2;

[0044] The rotating device 3 includes: a roller 31 and a driving device 32;

[0045] The roller 31 is in contact with the battery steel shell to be measured;

[0046] The driving device 32 drives the roller 31 to rotate.

[0047] The telescopic device 2, the image acquisition device 4, and the rotating device 3 are connected to the control device 5.

[0048] When it is necessary to detect the battery steel shell, the control device 5 controls the cylindrical light source 1 to extend into the battery steel shell to be detected. Subsequently, the control device 5 controls the image acquisition device 4 to acquire the surface image of the battery steel shell to be detected. During the acquisition process, the control device 5 controls the driving device 32 of the rotating device 3 to rotate. The driving device 32 drives the roller 31 to rotate, and the roller 31 drives the battery steel shell to rotate by friction, so that the image acquisition device 4 can obtain a complete image of the surface of the battery steel shell;

[0049] It should be noted that the driving device 32 can directly drive the roller by a motor or indirectly drive the roller by a motor driving a gear. In this embodiment, the roller 31 is directly driven by a motor.

[0050] The surface of the roller 31 is made of rubber material.

[0051] The control device 5 processes and judges the acquired image, and finally judges whether there are defects on the surface of the battery steel shell to be detected.

[0052] Although the present invention has been described herein with reference to illustrative embodiments of the present invention, it should be understood that those skilled in the art can design many other modifications and embodiments that will fall within the scope and spirit of the principles disclosed in this application. More specifically, within the scope of the disclosure of this application, various variations and improvements can be made to the components and / or layout of the subject combination layout. In addition to the variations and improvements made to the components and / or layout, other uses will also be apparent to those skilled in the art.

Claims

1. A method for detecting defects in a battery steel shell, characterized in that, Including the following steps, S1: Control the ambient brightness not higher than 150 lx. The control device controls the cylindrical light source to extend into the battery steel shell, and the control device controls the image acquisition device to acquire the surface image of the battery steel shell; S2: The control device controls the rotating device to rotate the battery steel shell, and controls the image acquisition device to acquire the surface image of the rotating battery steel shell to obtain a complete image of the surface of the battery steel shell; S3: The control device performs gray-scale processing on the obtained image to obtain a gray-scale image, and the control device performs binarization processing on the obtained gray-scale image to obtain a binarized image; S4: The control device identifies the binarized image to confirm whether there is a light spot on the image. If there is a light spot, it is determined that there is a defect on the battery steel shell; if there is no light spot, it is determined that there is no defect on the battery steel shell.

2. The method for detecting defects in a battery steel shell according to claim 1, characterized in that, The binarization processing in S3 is specifically: using the Otsu algorithm.

3. The method for detecting defects in a battery steel shell according to claim 1, characterized in that, In S1, the ambient brightness is controlled below 50 lx; The binarization processing in S3 is specifically: the global threshold method.

4. The method for detecting defects in a battery steel shell according to claim 1, characterized in that, The specific method of S2 is: The control device controls the image acquisition device to acquire an image of the battery steel shell. After the first acquisition is completed, the control device controls the rotating device to rotate the battery steel shell by 120°. When the rotation is completed, the control device controls the image acquisition device to acquire an image of the battery steel shell again. After the second acquisition is completed, the control device controls the rotating device to rotate the battery steel shell by 120°. The control device controls the image acquisition device to perform a final acquisition of the battery steel shell. A complete image of the surface of the battery steel shell is obtained through three acquisitions.

5. An apparatus for detecting defects in a battery steel shell, characterized in that, Using the battery steel shell defect detection method according to any one of claims 1-4, including: a cylindrical light source, a telescopic device, a rotating device, an image acquisition device, and a control device; The cylindrical light source is installed on the telescopic device; The rotating device is in contact with the battery steel shell to be measured; The telescopic device, the image acquisition device, and the rotating device are connected to the control device.

6. The apparatus for detecting defects in a battery steel shell according to claim 5, characterized in that, The cylindrical light source is the same length as the battery steel shell to be measured.

7. The apparatus for detecting defects in a battery steel shell according to claim 5, characterized in that, The rotating device includes: rollers and a driving device; The rollers are in contact with the battery steel shell to be measured; The driving device drives the rollers to rotate.

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