Industrial Technology Research Institute

Technology Overview

Most current battery modules are based on 18650 battery cells with resistance welding, and are used mainly in hand tools. Meanwhile, the small battery module has fewer battery cells and welding joints, and provides a shallow welding depth (the thickness of the tab needs to be < 0.3 mm). Thus, not only is manufacturing slow, but the pattern is only single-point and tab materials are limited to nickel and ferrous materials. The industry is gradually developing large-scale electric vehicles and energy storage; traditional battery cells are being replaced by large-capacity square cells, and thicker copper, aluminum (> 0.5mm) and other high conductivity and difficult welding metals are being adopted as tab materials. Existing resistance welding therefore cannot meet current requirements.

In order to solve this problem, intelligent laser welding derives from direct problem simulation, inverse problem simulation, and experimental data. Its welding technology greatly shortens the process adjustment time of 60%, and predicts post-welding quality in order to meet the energy storage demands of large-scale electric vehicles. When this technology is utilized to manufacture battery modules for electric buses, prototype vehicles are operational for nearly two years, and the modules meet original stability criteria. Unsurprisingly, the technology is becoming attractive to battery module customers, and has prompted industry to develop domestic intelligent laser welding battery module equipment. It is expected to also be applied in future industrial developments, including sustainable large-scale energy storage ecosystems.