JP2024109397A - Appearance inspection equipment for battery exterior body - Google Patents

Abstract

To provide a visual inspection device for battery outer package, capable of stably generating a highly accurate three-dimensional image with high speed irrespective of gloss anisotropy.SOLUTION: A visual inspection device 10 for battery outer package comprises a line scan camera 12, a luminaire 14, a conveyance mechanism, and an image processing system. The conveyance mechanism conveys the line scan camera 12 and the luminaire 14 with respect to the battery outer package 20 in at least one direction to thereby scan an imaging area 12a imaged by the line scan camera 12 over the battery outer package 20 and acquire imaging information by imaging external appearance of the battery outer package 20 with the line scan camera 12. The image processing system generates a three-dimensional shape image of the battery outer package on the basis of the imaging information.SELECTED DRAWING: Figure 1

Description

This disclosure relates to an external appearance inspection device for battery exterior bodies, and in particular to an external appearance inspection device for battery exterior bodies with a hairline finish applied to the surface.

A secondary battery comprises a battery body and a battery exterior (battery case) that protects the battery body. In addition, since the manufacturing of the battery exterior involves many processing steps, defects in shape such as dents and distortions may occur on the side of the battery exterior during the manufacturing process. In order to detect such defects in shape, various visual inspection methods have been proposed.

Patent document 1 discloses an appearance inspection method for inspecting the presence or absence of defects in the appearance of an object to be inspected, comprising the steps of: capturing an image of the object to be inspected to generate a two-dimensional image; detecting an area in the two-dimensional image that differs from a predetermined brightness value as a defect candidate; acquiring first three-dimensional data consisting of three-dimensional shape data of the object to be inspected seen from the same viewpoint as the viewpoint at which the two-dimensional image was captured, and data corresponding to each pixel of the two-dimensional image; setting a measurement line passing through the defect candidate area and its periphery in the two-dimensional image; extracting data corresponding to the measurement line in an area excluding the defect candidate area from the first three-dimensional data to generate second three-dimensional data; obtaining third three-dimensional data consisting of three-dimensional data obtained by interpolating the three-dimensional data of the area corresponding to the defect candidate area in the second three-dimensional data; and determining the difference between the first three-dimensional data and the third three-dimensional data for the data corresponding to the measurement line, and judging the presence or absence of a defect in the defect candidate area based on the magnitude of the difference value.

Patent Document 2 discloses a method for inspecting the appearance of a secondary battery, which includes a measurement step for measuring the three-dimensional shape of a battery case, and a display step for displaying each piece of measurement data obtained in the measurement step as a three-dimensional image, and when each piece of measurement data is plotted and displayed as the three-dimensional image, a shape having a difference in shading between the center and the edge is used as the plot shape of each piece of measurement data. In the appearance inspection method of Patent Document 2, an area camera is used as the imaging means in the measurement step.

JP 2008-292430 A JP 2015-059817 A

As described above, there is a demand for a method of inspecting battery exterior bodies. In particular, materials with hairline finish are sometimes used for battery exterior bodies, and the present disclosure has found that when inspecting secondary batteries having such battery exterior bodies, the cycle time becomes longer due to the anisotropy of the gloss. Such problems can occur particularly noticeably in large batteries.

Therefore, the present disclosure provides an external inspection device for battery exterior bodies that can stably generate highly accurate three-dimensional images at high speed, regardless of the anisotropy of gloss.

As a result of intensive research, the present inventors have found that the above problems can be solved by the following means, and have completed the present disclosure. That is, the present disclosure is as follows:
<Aspect 1>
An appearance inspection device for a battery exterior body,
The system is equipped with a line scan camera, a lighting device, a transport mechanism, and an image processing device.
the conveying mechanism conveys the line scan camera and the lighting device in at least one direction relative to the battery exterior body, thereby scanning an imaging area imaged by the line scan camera on the battery exterior body, and imaging information is obtained by imaging an external appearance of the battery exterior body with the line scan camera; and the image processing device generates a three-dimensional shape image of the battery exterior body based on the imaging information.
Visual inspection equipment.
<Aspect 2>
2. The appearance inspection device according to aspect 1, wherein a hairline finish is applied to a surface of the battery exterior body.
Aspect 3
3. The visual inspection apparatus according to aspect 1 or 2, wherein an angle and a vertical position of an illumination unit of the illumination device and a light receiving unit of the line scan camera relative to a battery exterior body are fixed.

According to the present disclosure, it is possible to provide an external inspection device for battery exterior bodies that can stably generate highly accurate three-dimensional images at high speed without being affected by the anisotropy of gloss. Furthermore, according to the present disclosure, it is possible to provide an external inspection device for battery exterior bodies that can stably generate highly accurate three-dimensional images at high speed without moving the battery during the external inspection of the battery exterior body.

Fig. 1(a) is a schematic diagram of an inspection using the appearance inspection device of the present disclosure when light from an illumination device is irradiated perpendicularly to a hairline portion of a battery exterior body. Fig. 1(b) is a view of Fig. 1(a) as viewed from the direction b. Fig. 2(a) is a schematic diagram of an inspection using the appearance inspection device of the present disclosure when light from an illumination device is irradiated parallel to the hairline portion of the battery exterior body. Fig. 2(b) is a view of Fig. 2(a) as viewed from the direction b. Fig. 3(a) is a schematic diagram of an inspection using the appearance inspection device of the present disclosure when light from an illumination device is irradiated perpendicularly to a hairline portion of a battery exterior body. Fig. 3(b) is a view of Fig. 3(a) as viewed from the direction b. Fig. 4(a) is a schematic diagram of an inspection using the appearance inspection device of the present disclosure when light from an illumination device is irradiated parallel to the hairline portion of the battery exterior body. Fig. 4(b) is a view of Fig. 4(a) as viewed from the direction b.

<Appearance inspection device>
As shown in FIGS. 1( a ) and 1 ( b ), the appearance inspection device 10 of the battery exterior body of the present disclosure includes:
The system includes a line scan camera 12, a lighting device 14, a transport mechanism (not shown), and an image processing device (not shown),
The conveying mechanism conveys the line scan camera 12 and the lighting device 14 in at least one direction relative to the battery exterior body 20, thereby scanning the imaging area 12a imaged by the line scan camera 12 on the battery exterior body 20, and capturing an image of the exterior of the battery exterior body 20 with the line scan camera 12 to obtain imaging information. And the image processing device generates a three-dimensional shape image of the battery exterior body based on the imaging information.

The above configuration allows stable and accurate three-dimensional images to be generated quickly without being affected by gloss anisotropy.

1(a) and (b), illumination light 14a from the lighting device 14 is irradiated perpendicularly to the hairline portion 22 of the battery exterior body 20, and the line scan camera 12 and lighting device 14 are transported in the direction X, so that the linear imaging area 12a imaged by the line scan camera 14a is scanned on the battery exterior body 20. In this way, the regular reflection component of the reflected light 14b is acquired by the line scan camera 12, and the external appearance of the battery exterior body 20 can be imaged to obtain imaging information.

With this appearance inspection device 10, as shown in Figures 2(a) and (b), even when the illumination light 14a from the illumination device 14 is irradiated parallel to the hairline portion 22 of the battery exterior body 20, it is possible to similarly image the appearance of the battery exterior body 20 and obtain imaging information.

In contrast, when using conventional appearance inspection equipment that uses an area camera, the anisotropy of gloss caused by the hairline finish grooves can be a problem.

More specifically, as shown in Figures 3(a) and (b), when a conventional appearance inspection device 10' using an area camera 16 is used to irradiate illumination light 14a from a lighting device 14 perpendicular to the direction of the unevenness of the hairline portion 22 of the battery exterior body 20, the illumination light 14a is diffusely reflected according to the angle of the unevenness of the hairline portion, and as a result, the reflected light 14b reaches the area camera over a wide range, resulting in a wide-ranging imaging area 16a.

On the other hand, as shown in Figures 4(a) and (b), when a conventional appearance inspection device 10' using an area camera is used to irradiate illumination light 14a from a lighting device 14 parallel to the direction of the unevenness of the hairline portion 22 of the battery exterior body 20, the illumination light 14a is not diffusely reflected as described above, and the reflected light 14b that reaches the area camera is limited to a narrow range where regular reflection occurs. As a result, the imaging area 16a becomes narrower, and the cycle time becomes longer.

The battery exterior body to be inspected with the appearance inspection device disclosed herein may be a battery exterior body having a hairline finish on its surface, and in particular, may be a battery exterior body having a metal foil with a hairline portion on its surface.

The components of this disclosure are explained below.

<Line scan camera>
A line scan camera is a camera that captures an image of an object as a line. The image of the object is captured while moving in at least one direction, particularly in a direction perpendicular to the imaging range, and the images captured as a line are stitched together to obtain a single image.

The position and angle of the light receiving section of the line scan camera may be set so that the specularly reflected component of the illumination from the lighting device reaches the light receiving section of the line scan camera.

The relative positions of the lighting device and the line scan camera, particularly the angle and vertical position of the lighting section of the lighting device and the light receiving section of the line scan camera relative to the battery exterior body, are preferably fixed in order to facilitate reception of the specularly reflected component of the lighting from the lighting device.

<Lighting Equipment>
The lighting device may be a device capable of irradiating the battery exterior body with pattern lighting, such as a sine stripe pattern.

It is preferable that the angle of the lighting unit of the lighting device relative to the battery exterior body is fixed, from the viewpoint of smoothly receiving the specular reflection component of the lighting from the lighting device at the light receiving unit of the line scan camera.

<Transport mechanism>
The transport mechanism is a mechanism for transporting the line scan camera and the lighting device in at least one direction relative to the battery exterior body. With this, the imaging area captured by the line scan camera is scanned on the battery exterior body, and the appearance of the battery exterior body is imaged by the line scan camera to obtain imaging information. In other words, with this transport mechanism, it is possible to perform the appearance inspection of the battery exterior body without moving the battery during the appearance inspection of the battery exterior body.

The transport mechanism may be a mechanism for transporting the line scan camera and the lighting device together in one direction relative to the battery exterior body. This one direction may be perpendicular to the linear imaging area of the line scan camera.

Image Processing Device
The image processing device is a device that generates a three-dimensional shape image of the battery exterior body based on imaging information. This device may be a known image processing device.

REFERENCE SIGNS LIST 10 Appearance inspection device of the present disclosure 10' Conventional appearance inspection device 12 Line scan camera 12a Imaging area of line scan camera 14 Illumination device 14a Illumination light 14b Reflected light of illumination light 16 Area camera 16a Imaging area of area camera 20 Battery exterior body 22 Hairline portion of battery exterior body

Claims (3)

An appearance inspection device for a battery exterior body,
The system is equipped with a line scan camera, a lighting device, a transport mechanism, and an image processing device.
the conveying mechanism conveys the line scan camera and the lighting device in at least one direction relative to the battery exterior body, thereby scanning an imaging area imaged by the line scan camera on the battery exterior body, and imaging information is obtained by imaging an external appearance of the battery exterior body with the line scan camera; and the image processing device generates a three-dimensional shape image of the battery exterior body based on the imaging information.
Visual inspection equipment. The appearance inspection device according to claim 1, wherein the surface of the battery exterior body is subjected to a hairline finish. The visual inspection device according to claim 1 or 2, wherein the angle and vertical position of the illumination unit of the illumination device and the light receiving unit of the line scan camera relative to the battery exterior body are fixed.

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