Battery cell voltage sampling piece welding quality detection method and detection device

Abstract

The invention relates to a battery cell voltage sampling piece welding quality detection method and a detection device. The detection method comprises the following steps: a voltage drop test step, namely testing whether voltage drop in a welding area of a test object meets preset conditions by adopting a voltage drop method; and a comprehensive assessment step, namely obtaining the final weldingquality according to results obtained in the voltage drop test step. The voltage drop test specifically comprises the following steps: 101) introducing a direct current source between the welding areaand battery cell tabs, and controlling stable output of the direct current source; and 102) measuring voltage drop between the welding area and the battery cell tabs, judging whether the voltage dropmeets the preset conditions, if so, exiting, otherwise generating alarm information. Compared with the prior art, the method disclosed by the invention has the advantages that the welding quality canbe effectively evaluated, thermal runaway risk of the battery module is reduced, and the like.

Description

technical field [0001] The invention relates to the technical field of battery modules, in particular to a method and a detection device for detecting the welding quality of a cell voltage sampling sheet. Background technique [0002] After the development of the electric vehicle industry, more and more vehicle battery module technologies have been produced. The battery module is mainly composed of batteries. The voltage of the cell needs to be monitored, so the voltage sampling on each cell becomes a necessary measure. Now there are many different cell voltage sampling methods: [0003] 1. The wire harness is used as the voltage sampling line, and the voltage sampling end of the wire harness is connected with the battery aluminum (copper) bar by ultrasonic welding. [0004] 2. The aluminum bar is used as the voltage sampling line, and the voltage sampling end of the wiring harness is connected with the battery aluminum (copper) bar by ultrasonic welding. [0005] 3. Cop...

AI Technical Summary

Problems solved by technology

[0006] Among them, the wiring harness is used as a sampling line, which will introduce inconsistency and uncertainty in manual assembly, and reduce quality reliability during processing.

The use of ultrasonic welding will increase the complexity of the process (requires subassembly, and then integrated processing), and increase the difficulty of design (the increase in thickness leads to difficulty in assembly)

[0007] In the third method above, due to the instability of laser welding (thermal lens effect, etc.), sometimes there will be virtual welding, resulting in failure of voltage sampling

After the occurrence of false welding, visual inspection cannot effectively detect the failure of virtual welding. The existing defect is: the failure of laser welding at the voltage sampling point cannot be effectively found

[0008] Existing technical means cannot detect welding quality under the premise of non-destructiveness, including physical properties such as welding strength and chemical properties such as electrical resistivity

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