A method and apparatus for detecting weld penetration depth
By using ultrasonic scanning imaging and laser sensors to mark the projection lines on the battery end face, the destructive and inefficient problems of existing weld penetration detection methods have been solved, achieving non-destructive and efficient weld penetration detection.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SBT ULTRASONIC TECH CO LTD
- Filing Date
- 2024-12-30
- Publication Date
- 2026-06-30
AI Technical Summary
Existing weld penetration testing technologies suffer from problems such as destructive testing, high testing costs, incomplete testing, and low testing efficiency. In particular, when testing with a metallographic microscope, the product needs to be cut, making it impossible to confirm whether the weld penetration of the uncut parts meets the standards.
By employing ultrasonic scanning imaging combined with laser sensors and image processing technology, the battery casing and reference block are fixed by a fixture, and non-destructive testing is performed using an ultrasonic probe and nozzle to obtain the weld penetration depth. The laser sensor marks the projection lines on the battery end face, thus achieving non-destructive measurement.
It enables non-destructive measurement of weld penetration depth, improves inspection efficiency and accuracy, avoids missed detection of local penetration depth defects, simplifies the inspection process, and reduces inspection costs.
Smart Images
Figure CN122306941A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of ultrasonic scanning detection technology, specifically relating to a method and device for detecting weld penetration depth. Background Technology
[0002] The end caps of square aluminum-cased lithium batteries are typically connected to the aluminum casing using laser welding. The depth of the laser weld pool is a crucial indicator of weld quality. Currently, major lithium battery manufacturers use a method of sampling square aluminum-cased lithium batteries produced in a proportional manner, then cutting and grinding the weld seams of the samples, and observing and measuring the weld penetration depth using a metallographic microscope.
[0003] The inventors have discovered that existing laser welding penetration depth detection technologies have at least the following technical problems:
[0004] On the one hand, metallographic microscopy requires cutting the product for inspection, which is a destructive test and has high inspection costs. Furthermore, metallographic microscopes can only measure the weld penetration at the cut. Due to the limited cut surface, it is impossible to confirm whether the weld penetration in the uncut area meets the standard, which makes the inspection incomplete and easily leads to problems such as missed detection of local penetration defects. On the other hand, a square aluminum shell needs to be cut, polished, acid-washed and cleaned multiple times before being observed and measured by a metallographic microscope. The entire inspection process is cumbersome and generally takes several hours, resulting in low inspection efficiency.
[0005] Therefore, it is necessary to improve the existing technology to overcome its shortcomings in practical applications. Summary of the Invention
[0006] Based on the aforementioned shortcomings and deficiencies in the prior art, one of the objectives of this invention is to at least solve one or more of the aforementioned problems in the prior art. In other words, one of the objectives of this invention is to provide a welding penetration depth detection method and detection device that meets one or more of the aforementioned requirements.
[0007] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:
[0008] This invention provides a method for detecting weld penetration depth, comprising the following steps:
[0009] The battery case and the reference block are installed using clamps to keep the relative positions of the battery case and the reference block fixed.
[0010] Install the ultrasonic probe inside the nozzle and place it upside down under the battery casing;
[0011] Water is sprayed from bottom to top onto the bottom of the battery casing molten pool and the reference block through a nozzle, while an ultrasonic probe scans the reference surface of the bottom of the battery casing molten pool and the reference block to obtain scan images of the reference surface of the reference block and the bottom of the battery casing molten pool.
[0012] Obtain the relative position of the reference surface of the reference block and the end face of the battery case, and mark the position of the end face of the battery case on the scanned images of the reference surface of the reference block and the bottom of the molten pool of the battery case. Measure the distance between the end face of the battery case and the bottom of the molten pool of the battery case through image processing to obtain the weld penetration depth.
[0013] As a preferred embodiment, the reference block is configured with a first reference surface and a second reference surface, wherein the first reference surface is arranged parallel to the end face of the battery casing, and the second reference surface is arranged perpendicular to the end face of the battery casing.
[0014] As a preferred embodiment, a laser sensor is used to measure the distance to the first reference surface to obtain the relative positions between the first reference surface, the second reference surface, and the end face of the battery casing.
[0015] As a preferred embodiment, an ultrasonic probe is used to scan an area to obtain a scanned image. The area scanned by the ultrasonic probe is larger than the area formed between the first reference plane, the second reference plane, the bottom of the battery casing molten pool, and the weld detection point.
[0016] As a preferred embodiment, the scanned image is processed to mark the relative position of the bottom of the battery casing molten pool with respect to the first reference plane and the second reference plane.
[0017] As a preferred embodiment, the position of the battery casing end face is marked in the scanned image according to the relative position of the battery casing end face with the first reference plane and the second reference plane.
[0018] As a preferred embodiment, the distance between the bottom of the battery casing molten pool and the end face of the battery casing is measured by image processing in a direction parallel to the second reference plane to obtain the weld penetration depth.
[0019] The present invention also provides a welding penetration depth detection device, which is applied to the detection method described in any of the above schemes. The detection device includes a worktable, a three-axis mechanism and a fixture. The fixture and the three-axis mechanism are mounted on the worktable, and the nozzle and the ultrasonic probe are mounted on the three-axis mechanism. The three-axis mechanism is used to move the nozzle and the ultrasonic probe so that the nozzle sprays water from bottom to top and the ultrasonic probe performs scanning detection.
[0020] As a preferred embodiment, a water tank is provided on the workbench, and the clamp is installed in the water tank for collecting wastewater.
[0021] Compared with the prior art, the beneficial effects of this invention are:
[0022] This invention provides a method for detecting weld penetration depth. It uses the principle of ultrasonic scanning imaging to non-destructively measure weld penetration depth. By using a laser sensor combined with an algorithm to mark the projection lines of the battery end face on the ultrasonic scanning image, it makes up for the inability of the ultrasonic probe to clearly image the battery end face, and overcomes the influence of uneven battery end face on measurement accuracy. Attached Figure Description
[0023] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other embodiments can be obtained from these drawings without creative effort.
[0024] Figure 1 This is a schematic flowchart of a welding penetration depth detection method according to an embodiment of the present invention;
[0025] Figure 2 This is a cross-sectional view of the weld pool of the battery casing according to an embodiment of the present invention;
[0026] Figure 3 yes Figure 2 A magnified view of a section at point A in the middle;
[0027] Figure 4 This is a schematic diagram of the installation of the clamp, reference block, and battery casing according to an embodiment of the present invention;
[0028] Figure 5 This is a schematic diagram of the detection principle of an embodiment of the present invention;
[0029] Figure 6 This is a schematic diagram of calculating the welding penetration depth in a scanned image based on the relative position of the reference surface of the reference block and the end face of the battery case, according to an embodiment of the present invention.
[0030] Figure 7 This is a schematic diagram of the structure of the battery casing end face determined by the limiting block according to an embodiment of the present invention;
[0031] Figure 8 This is a schematic diagram of the structure of a welding penetration detection device according to an embodiment of the present invention;
[0032] In the figure: 1. Fixture, 11. Limiting block, 2. Battery casing, 21. Battery casing end face, 22. Bottom of molten pool, 23. Weld molten pool, 3. Reference block, 31. First reference surface, 32. Second reference surface, 4. Nozzle, 5. Ultrasonic probe, 6. Laser sensor, 71. Worktable, 72. Three-axis mechanism, 73. Water tank. Detailed Implementation
[0033] To more clearly illustrate the embodiments of this application, the specific implementation methods of this application will be described below with reference to the accompanying drawings. Obviously, the drawings described below are merely some embodiments of this application. For those skilled in the art, other drawings and other implementation methods can be obtained based on these drawings without any creative effort.
[0034] In the description of the embodiments of this application, the terms "upper," "lower," "front," "rear," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. In addition, the terms "first," "second," etc., are only used for distinction in description and have no special meaning.
[0035] In existing technologies, to inspect the weld pool of a square aluminum-cased lithium battery end cap and aluminum casing welded together by laser, such as... Figures 2 to 3 As shown, the weld pool 23 of the battery casing 2 is located inside the battery casing 2. It is usually inspected using a metallographic microscope. Metallographic microscope inspection requires cutting the product for inspection, which is a destructive inspection and has a high inspection cost. In addition, the metallographic microscope can only measure the weld penetration at the cut. Due to the limited cutting surface, it cannot confirm whether the weld penetration of the uncut part meets the standard, which makes the inspection incomplete and easily leads to the omission of local penetration defects. On the other hand, since a square aluminum shell needs to be cut, polished, acid-washed and cleaned multiple times before being observed and measured by a metallographic microscope, the whole inspection process is cumbersome and generally takes several hours, resulting in low inspection efficiency.
[0036] To address the aforementioned technical problems, some embodiments of this application are described below. Figures 1 to 7 As shown, a method for detecting weld penetration depth is provided, comprising the following steps:
[0037] S1. Install the battery case 2 and the reference block 3 using the clamp 1 to keep the relative positions of the battery case 2 and the reference block 3 fixed.
[0038] Specifically, two reference blocks 3 are fixed on the left and right sides of the clamp 1, and the battery case 2 is installed above the clamp 1, so that the reference blocks 3 and the end face 21 of the battery case are pressed together and kept in a fixed relative position. The structure of the reference blocks and the clamp is not limited to the above form; the clamp only needs to ensure that the relative position of the reference blocks and the battery remains unchanged.
[0039] Furthermore, a first reference surface 31 and a second reference surface 32 are configured on the reference block 3. The first reference surface 31 is arranged parallel to the end face 21 of the battery case, and the second reference surface 32 is arranged perpendicular to the end face 21 of the battery case. The first reference surface 31 and the second reference surface 32 are arranged perpendicular to each other.
[0040] S2. Install the ultrasonic probe 5 inside the nozzle 4 and place it upside down below the battery case 2.
[0041] Specifically, the ultrasonic probe 5 is installed in the nozzle 4, and the nozzle 4 is installed on the detection device so that the nozzle 4 sprays water on the battery case 2 and the reference block 3 from bottom to top, and the ultrasonic probe 5 scans and detects the battery case 2 and the reference block 3 from bottom to top.
[0042] S3. Water is sprayed from bottom to top onto the bottom 22 of the battery casing molten pool and the reference block 3 through the nozzle 4. At the same time, the ultrasonic probe 5 scans the reference surface of the bottom 22 of the battery casing molten pool and the reference surface of the reference block 3 to obtain the scan image of the reference surface of the reference block 3 and the bottom 22 of the battery casing molten pool.
[0043] Specifically, the nozzle 4 is activated to spray water onto the bottom 22 of the molten pool of the battery casing 2 and the reference block 3 from bottom to top. At the same time, the ultrasonic probe 5 scans the reference surfaces of the bottom 22 of the molten pool of the battery casing and the reference block 3 in sequence. The ultrasonic probe 5 scans the area to obtain the scanned image. The area scanned by the ultrasonic probe 5 is larger than the area formed between the first reference surface 31, the second reference surface 32, the bottom 22 of the molten pool of the battery casing, and the weld detection point.
[0044] Furthermore, the scanned image is processed to mark the relative positions of the bottom 22 of the battery casing molten pool with the first reference surface 31 and the second reference surface 32.
[0045] S4. Obtain the relative position of the reference surface of the reference block 3 and the end face 21 of the battery case, and mark the position 21 of the end face 21 of the battery case on the reference surface of the reference block 3 and the scanned image of the bottom of the molten pool 22 of the battery case. Measure the distance between the end face 21 of the battery case and the bottom of the molten pool 22 of the battery case through image processing to obtain the weld penetration depth.
[0046] In some specific embodiments, the laser sensor 6 measures the distance to the first reference surface 31 to obtain the relative positions between the first reference surface 31, the second reference surface 32, and the battery casing end face 21.
[0047] Furthermore, such as Figure 6 As shown, the position of the battery casing end face 21 is marked in the scanned image according to the relative position of the battery casing end face 21 with the first reference surface 31 and the second reference surface 32.
[0048] Furthermore, in a direction parallel to the second reference plane 32, the distance between the bottom 22 of the battery casing molten pool and the end face 21 of the battery casing is measured by image processing to obtain the weld penetration depth α.
[0049] In some specific embodiments, such as Figure 7As shown, the weld penetration depth of the battery casing can also be determined mechanically by setting a limiting block. Specifically, water is sprayed between the bottom of the molten pool of the battery casing and the side end face of the limiting block through a nozzle. At the same time, an ultrasonic probe scans the bottom of the molten pool and the side end face of the limiting block to obtain an ultrasonic scan image. The distance β between the bottom of the molten pool and the side end face of the limiting block is then calculated. Combined with the known width δ of the limiting block, the weld penetration depth α can be calculated, i.e., α = β - δ. This method has a simple structure, and the limiting block is not limited to the shape and position shown in the figure, as long as two parallel reference planes can be provided, and the ultrasonic probe can form a clear image.
[0050] According to some embodiments of this application, the welding penetration depth is measured non-destructively by using the principle of ultrasonic scanning imaging. The projection lines of the battery end face are marked on the ultrasonic scanning image by a laser sensor combined with an algorithm to make up for the inability of the ultrasonic probe to clearly image the battery end face, and at the same time overcome the influence of uneven battery end face on measurement accuracy.
[0051] According to some embodiments of this application, such as Figure 8 As shown, a welding penetration depth detection device is also provided, which is applied to the detection method described above. The detection device includes a worktable 71, a three-axis mechanism 72, and a fixture 1. The fixture 1 and the three-axis mechanism 72 are mounted on the worktable 71, and the nozzle 4 and the ultrasonic probe 5 are mounted on the three-axis mechanism 72. The three-axis mechanism 72 is used to move the nozzle 4 and the ultrasonic probe 5 so that the nozzle 4 sprays water from bottom to top, and the ultrasonic probe 5 performs scanning detection.
[0052] Furthermore, the three-axis mechanism 72 includes an X-axis motion mechanism, a Y-axis motion mechanism, and a Z-axis motion mechanism. Y-axis motion mechanisms are respectively provided on the left and right sides of the worktable. The two ends of the X-axis motion mechanism are respectively connected to the two Y-axis motion mechanisms. The X-axis motion mechanism is connected to the Z-axis motion mechanism. A nozzle and an ultrasonic probe are installed on the Z-axis motion mechanism. The X-axis motion mechanism, Y-axis motion mechanism, and Z-axis motion mechanism work together to control the movement of the nozzle and ultrasonic probe in the XZY three-dimensional coordinate system and to scan the battery case and reference block from bottom to top.
[0053] In some specific embodiments, a water tank 73 is configured on the workbench 71, and a clamp 1 is installed in the water tank 73 for collecting wastewater.
[0054] In the description of the embodiments of this application, unless otherwise expressly specified and limited, the technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.
[0055] The above description is only a detailed explanation of the preferred embodiments and principles of this application. For those skilled in the art, there may be changes in the specific implementation based on the ideas provided by this invention, and these changes should also be considered within the scope of protection of this application.
Claims
1. A method for detecting weld penetration depth, characterized in that, Includes the following steps: The battery case and the reference block are installed using clamps to keep the relative positions of the battery case and the reference block fixed. Install the ultrasonic probe inside the nozzle and place it upside down under the battery casing; Water is sprayed from bottom to top onto the bottom of the battery casing molten pool and the reference block through a nozzle, while an ultrasonic probe scans the reference surface of the bottom of the battery casing molten pool and the reference block to obtain scan images of the reference surface of the reference block and the bottom of the battery casing molten pool. Obtain the relative position of the reference surface of the reference block and the end face of the battery case, and mark the position of the end face of the battery case on the scanned images of the reference surface of the reference block and the bottom of the molten pool of the battery case. Measure the distance between the end face of the battery case and the bottom of the molten pool of the battery case through image processing to obtain the weld penetration depth.
2. The method for detecting weld penetration depth according to claim 1, characterized in that, The reference block is configured with a first reference surface and a second reference surface. The first reference surface is arranged parallel to the end face of the battery casing, and the second reference surface is arranged perpendicular to the end face of the battery casing.
3. The method for detecting weld penetration depth according to claim 2, characterized in that, A laser sensor is used to measure the distance to the first reference surface to obtain the relative positions between the first reference surface, the second reference surface, and the end face of the battery casing.
4. The method for detecting weld penetration depth according to claim 2, characterized in that, The ultrasonic probe scans an area to obtain a scanned image. The area scanned by the ultrasonic probe is larger than the area formed between the first reference plane, the second reference plane, the bottom of the battery casing molten pool, and the weld detection point.
5. The method for detecting weld penetration depth according to claim 4, characterized in that, The scanned images are processed to mark the relative positions of the bottom of the battery casing molten pool with the first reference plane and the second reference plane.
6. The method for detecting weld penetration depth according to claim 5, characterized in that, Based on the relative positions of the battery casing end face with the first reference plane and the second reference plane, the position of the battery casing end face is marked in the scanned image.
7. The method for detecting weld penetration depth according to claim 6, characterized in that, In a direction parallel to the second reference plane, the distance between the bottom of the battery casing molten pool and the end face of the battery casing is measured by image processing to obtain the weld penetration depth.
8. A welding penetration depth detection device, characterized in that, The detection device, applicable to any one of claims 1 to 7, includes a worktable, a three-axis mechanism, and a fixture. The fixture and the three-axis mechanism are mounted on the worktable, and the nozzle and the ultrasonic probe are mounted on the three-axis mechanism. The three-axis mechanism is used to move the nozzle and the ultrasonic probe so that the nozzle sprays water from bottom to top, and the ultrasonic probe performs scanning detection.
9. A welding penetration detection device according to claim 8, characterized in that, A water tank is provided on the workbench, and the clamp is installed in the water tank for collecting wastewater.