Laser welding effect testing method and fixture for lithium ion battery

Abstract

The invention discloses a laser welding effect testing method and testing fixture for a lithium ion battery. According to the testing method, a tensile testing machine, the testing fixture and the to-be-tested battery are provided. The battery comprises a positive electrode tab and a cover cap connected with the positive electrode tab; the positive electrode tab comprises a first positive electrode tab segment and a second positive electrode tab segment, wherein the first positive electrode tab segment is welded to the cover cap through a laser, the second positive electrode tab segment and the first positive electrode tab segment are disposed at an included angle, and the first positive electrode tab segment and the cover cap are disposed at an acute angle. The method includes the following steps that S10, the position of the first positive electrode tab segment is maintained unchanged with respect to the cover cap, and the second positive electrode tab segment is pressed to be straight in the direction of the first positive electrode tab segment, so that the first positive electrode tab segment and the second positive electrode tab segment are located on the same straight line; S20, the cover cap is placed on the testing fixture, and the tensile testing machine is used for stretching the second positive electrode tab segment in the length direction of the first positive electrode tab segment. The testing method can be used for more realistically evaluating the welding effect between the positive electrode tab and the cover cap.

Description

technical field [0001] The invention relates to the technical field of batteries, in particular to a method for testing the laser welding effect of a lithium-ion battery and a test fixture thereof. Background technique [0002] The laser welding capping process is a key process in the manufacturing process of cylindrical lithium-ion batteries, such as figure 1 As shown, after the positive electrode ear 2' is welded to the cap 1', it is necessary to bend part of the positive electrode ear 2' relative to the cap 1' to a certain extent (that is, the positive electrode ear 2' is not welded vertically on the cap 1'), and then Buckle the cap 1' on the mouth of the steel case. The welding effect of laser welding is generally detected by a tensile testing machine to quantify and judge the welding effect of laser welding. [0003] The general laser welding effect test method is to remove the cap 1' together with the positive tab 2' from the battery and then use a tensile testing ma...

AI Technical Summary

Problems solved by technology

After the cylindrical battery is formed, the positive tab 2' is not welded vertically on the cap 1', and in the prior art, the tensile testing machine stretches the positive tab 2' in a direction perpendicular to the cap 1'. This test method will affect the test results. Causes a large error and cannot accurately evaluate the laser welding effect between the positive tab 2' and the cap 1'

Images