Method and device for detecting resistance welding strength of lithium ion battery

Abstract

The invention discloses a detection method for the resistance welding strength of a lithium ion battery, which comprises the following steps: using a white coaxial light source to irradiate the resistance solder joints of the conductive connecting sheet of the lithium ion battery to be detected and the battery shell; collecting and enlarging the solder joint images And transmit it to the computer; use the image processing software to extract and analyze the gray value and area parameter of each pixel in the solder joint image, and compare the analysis results with the preset solder joint characteristic parameter threshold threshold, judge Whether the strength of the solder joint is qualified. The invention adopts non-contact and non-destructive optical imaging method to detect the solder joints, not only does not cause any damage or damage to the solder joints, but also the detection process is accurate and efficient, and 100% online full inspection can be realized, effectively reducing the risk of virtual solder joints , to meet the actual needs of mass production. In addition, the invention also discloses a detection device for the resistance welding strength of the lithium ion battery.

Description

technical field [0001] The invention relates to a method and device for detecting welding strength, in particular to a method and device for detecting resistance welding strength of a lithium ion battery. Background technique [0002] In recent years, with the rapid development and wide application of lithium-ion battery products, the requirements for safety and product quality are also increasing. Therefore, it is very important to ensure the reliability of the internal solder joints of lithium-ion batteries. [0003] At present, for the welding of the anode conductive connecting piece (T2 material copper strip) and the battery case (cold-rolled nickel-plated steel case) inside the cylindrical 18650 lithium-ion battery, the industry generally adopts the resistance welding process. However, the melting points of these two metal base materials are quite different, copper is 1080°C, and steel is 1530°C; the thermal conductivity of the two is also very different, copper is 401W...

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Problems solved by technology

For example, Chinese patent application No. 201020526039.4 provides a resistance spot welding spot detection device, Chinese patent application No. 200610097980.7 provides a curtain wire solder spot detector, and Chinese patent application No. A detection device for the welding strength of the tabs of lithium-ion batteries. The common feature of the three is: the mechanical tensile strength is tested by applying an external force to the weld. This is a destructive test, and the test itself will affect the reliability of the solder joints. cause a certain degree of impact, especially for solder joints whose tensile strength is close to the specification control line; in addition, the above method needs to use specific fixtures, which will affect the efficiency, so it is generally only suitable for sampling inspection, and it is difficult to apply in large 100% full inspection and monitoring is carried out in large-scale continuous production, so that the solder joint strength of the product inevitably has certain quality risks and potential safety hazards

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