Joining lithium–ion batteries into packs using small-scale resistance spot welding

Abstract

This paper presents selected problems of small scale resistance spot welding in the construction and usage of lithium–ion batteries. A few ready-made battery packs were examined with the help of reverse engineering. The chemical composition of selected elements was investigated and the joints underwent metallographic examination (both macro- and microscopic).

A prototype of a small-scale resistance welding machine was designed for joining batteries into packs and the prototype was tested. A series of sample joints were made and tested for resistance and strength. A similar course of tests was administered to the original pack. It was found that there is a difference between the sample and the original joints in their diameter and levels of resistance. Suggestions are made for further developments in the welding machine's control system to improve the quality of the joints.