US-12617035-B2 - Welding detection apparatus and welding detection method

US12617035B2US 12617035 B2US12617035 B2US 12617035B2US-12617035-B2

Abstract

A welding detection apparatus is used for detecting a weld seam between a case and a top cover of a battery, and includes: an image acquisition component configured to shoot the weld seam, the image acquisition component being located obliquely above an outer side of the weld seam and forming an included angle with a height direction of the battery; and a controller configured to obtain a protruding height of the weld seam relative to a reference surface area on an outer side wall of the case according to a first distance between the image acquisition component and the outer side wall of the case, a second distance between the image acquisition component and the weld seam, and the included angle, and compare the protruding height with a preset height threshold to determine whether the protruding height of the weld seam is qualified.

Inventors

Liangjin HU
Lin Ma

Assignees

CONTEMPORARY AMPEREX TECHNOLOGY CO., LIMITED

Dates

Publication Date: 20260505
Application Date: 20250515
Priority Date: 20240125

Claims (15)

1 . A welding detection apparatus for detecting a weld seam between a case and a top cover of a battery, the detection apparatus comprising: an image acquisition component configured to shoot the weld seam, the image acquisition component being located obliquely above an outer side of the weld seam and forming an included angle with a height direction of the battery; and a processor configured to obtain a protruding height of the weld seam relative to a reference surface area on an outer side wall of the case according to a first distance between the image acquisition component and the outer side wall of the case, a second distance between the image acquisition component and the weld seam, and the included angle, and compare the protruding height with a preset height threshold to determine whether the protruding height of the weld seam is qualified; and configured to establish at least one plane parallel to the outer side wall of the case in an image to intersect with the weld seam to obtain an intersecting line which is a contour line of a surface of the weld seam, perform linear fitting on at least three points on the intersecting line to obtain a spatial straight line, calculate a distance between each of the at least three points and the spatial straight line, and compare the distance with a preset distance threshold to determine whether an appearance defect exists in the weld seam.
2 . The welding detection apparatus according to claim 1 , wherein the image acquisition component is a first image acquisition component located on one of two sides of the battery along a width direction, the welding detection apparatus further comprising: a second image acquisition component located on another one of the two sides of the battery along the width direction, wherein the first image acquisition component and the second image acquisition component are configured to move along a length direction of the battery relative to the weld seam in a detection process.
3 . The welding detection apparatus according to claim 1 , wherein the processor is further configured to: determine that the protruding height of the weld seam is unqualified in a case that a plurality of positions with the protruding height exceeding the preset height threshold exist on the weld seam within a first preset distance range in an extension direction of the weld seam and a number exceeds a preset value.
4 . The welding detection apparatus according to claim 1 , wherein the processor is further configured to select a maximum value of the protruding height of the weld seam in the height direction at a same position in an extension direction of the weld seam.
5 . The welding detection apparatus according to claim 1 , wherein the reference surface area is preset to be spaced apart from the weld seam in the height direction.
6 . The welding detection apparatus according to claim 1 , wherein the processor is further configured to: divide the weld seam into a plurality of detection areas in an extension direction of the weld seam; determine a sub-reference surface area corresponding to each of the plurality of detection areas on an outer surface of the case; and when obtaining the protruding height of the weld seam in each of the plurality of detection areas, use the determined sub-reference surface area corresponding to the each of the plurality of detection areas for calculation.
7 . The welding detection apparatus according to claim 1 , wherein the processor is further configured to: determine that the appearance defect exists in the weld seam in a case that points with the distance exceeding the preset distance threshold consecutively exist on the weld seam within a second preset distance range in an extension direction of the weld seam.
8 . The welding detection apparatus according to claim 1 , wherein the processor is further configured to determine a type of the appearance defect in the weld seam according to a deviation direction and positions of the points with the distance exceeding the preset distance threshold relative to the straight spatial line in a case that the appearance defect exists in the weld seam.
9 . A welding detection method, performed by the welding detection apparatus according to claim 1 , for detecting a weld seam between a case and a top cover of a battery, comprising: obtaining a protruding height of the weld seam relative to a reference surface area on an outer side wall of the case according to a first distance between an image acquisition component and the outer side wall of the case, a second distance between the image acquisition component and the weld seam, and an included angle, wherein the image acquisition component is configured to shoot the weld seam, and the image acquisition component is located obliquely above an outer side of the weld seam and forms the included angle with a height direction of the battery; comparing the protruding height with a preset height threshold to determine whether the protruding height of the weld seam is qualified; establishing at least one plane parallel to the outer side wall of the case in an image to intersect with the weld seam to obtain an intersecting line which is a contour line of a surface of the weld seam; performing linear fitting on at least three points on the intersecting line to obtain a spatial straight line, and calculating a distance between each of the at least three points and the spatial straight line; and comparing the distance with a preset distance threshold to determine whether an appearance defect exists in the weld seam.
10 . The welding detection method according to claim 9 , wherein comparing the protruding height with the preset height threshold to determine whether the protruding height of the weld seam is qualified comprises: determining that the protruding height of the weld seam is unqualified in a case that points with the protruding height exceeding the preset height threshold consecutively exist on the weld seam within a first preset distance range in an extension direction of the weld seam.
11 . The welding detection method according to claim 9 , wherein a maximum value of the protruding height of the weld seam in the height direction is selected at a same position in an extension direction of the weld seam.
12 . The welding detection method according to claim 9 , wherein the reference surface area is preset to be spaced apart from the weld seam in the height direction.
13 . The welding detection method according to claim 9 , further comprising: dividing the weld seam into a plurality of detection areas in an extension direction of the weld seam; determining a sub-reference surface area corresponding to each of the plurality of detection areas on an outer surface of the case, the reference surface area comprising a plurality of sub-reference surface areas; and when obtaining the protruding height of the weld seam in each of the plurality of detection areas, using the determined sub-reference surface area corresponding to the each of the plurality of detection areas for calculation.
14 . The welding detection method according to claim 9 , wherein comparing the distance with the preset distance threshold to determine whether the appearance defect exists in the weld seam comprises: determining that the appearance defect exists in the weld seam in a case that points with the distance exceeding the preset distance threshold consecutively exist on the weld seam within a second preset distance range in an extension direction of the weld seam.
15 . The welding detection method according to claim 9 , wherein the weld seam appearance defect detection step further comprises: determining a type of the appearance defect in the weld seam according to a deviation direction and positions of the points with the distance exceeding the preset distance threshold relative to the spatial straight line in a case that the appearance defect exists in the weld seam.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS The present application is a continuation of International Application No. PCT/CN2024/084067, filed on Mar. 27, 2024, which claims priority to Chinese Patent Application No. 202410106550.5, filed with the China National Intellectual Property Administration on Jan. 25, 2024 and entitled “WELDING DETECTION APPARATUS AND WELDING DETECTION METHOD”, which are incorporated herein by reference in their entirety. TECHNICAL FIELD The present application relates to the technical field of battery assembly detection, and in particular to a welding detection apparatus and a welding detection method. BACKGROUND The statement here merely provides background information related to the present application and does not necessarily constitute the related art. In recent years, new energy vehicles have made a leap forward in development. In the field of electric vehicles, power batteries play an irreplaceable role as the power source of electric vehicles. With the vigorous promotion of new energy vehicles, the demand for power battery products is also increasing day by day. As the core component of new energy vehicles, batteries have high requirements on use reliability. The connection between the top cover and the case of the battery is achieved through welding. If various defects occur in the weld seam, it will pose a great safety risk to the battery. At present, the production line detects the weld seam through manual visual inspection and manual touch, resulting in low accuracy in determining the defect in the weld seam. SUMMARY The purpose of the present application is to improve the accuracy of detecting the weld seam on the top cover of the battery. According to a first aspect, the present application provides a welding detection apparatus for detecting a weld seam between a case and a top cover of a battery. The detection apparatus includes: an image acquisition component configured to shoot the weld seam, the image acquisition component being located obliquely above an outer side of the weld seam and forming an included angle with a height direction of the battery; anda controller configured to obtain a protruding height of the weld seam relative to a reference surface area on an outer side wall of the case according to a first distance between the image acquisition component and the outer side wall of the case, a second distance between the image acquisition component and the weld seam, and the included angle, and compare the protruding height with a preset height threshold to determine whether the protruding height of the weld seam is qualified. In this embodiment, the image acquisition component is arranged at a suitable shooting angle to obtain the distance between the image acquisition component and the outer side wall of the case and the weld seam, thus obtaining the protruding height of the weld seam relative to the outer side wall of the case, and determining whether the protruding height of the weld seam is qualified. This method can automatically detect the flange dimension defect of the battery, improve the detection accuracy, reduce missed detections, and thus reduce the risk caused by abnormal flange dimension to the working safety of the battery. In some embodiments, the battery is provided with one image acquisition component respectively on two sides along a width direction of the battery, and the image acquisition component is configured to move along a length direction of the battery relative to the weld seam in a detection process. This embodiment can detect the protruding height of the weld seam of the battery relative to the outer side wall of the case more quickly and efficiently, and the detection processes of the weld seam on two sides do not interfere with each other. In some embodiments, the controller is configured to: determine that the protruding height of the weld seam is unqualified in a case that multiple positions with the protruding height exceeding the preset height threshold exist on the weld seam within a first preset distance range in an extension direction of the weld seam and the number exceeds a preset value. In this embodiment, only when multiple points with the protruding height exceeding the preset value exist in the extension direction of the weld seam, it will be determined that the protruding height has a defect. This determination logic indicates that there is indeed a small segment of the weld seam with the protruding height exceeding the preset value, thus reducing the probability of false detection, avoiding the detection error caused by the shaking of the image acquisition components during the relative movement of the battery, and improving the detection accuracy of the welding. In some embodiments, the controller is configured to select a maximum value of the protruding height of the weld seam in the height direction at the same position in the extension direction of the weld seam. In this embodiment, the maximum value of the