Lead-Free Conductors with a Surface Treatment Ensuring a Low Melting Temperature

Abstract

In order to protect the environment and to ensure sustainability, it is prohibited to use lead materials in the production of automotive components. As part of soldering, busbars are used that usually have a copper core and a coating made of tin, but the melting point of such material is high, which poses a problem during soldering. This article discusses the case where a busbar is interconnected with another conductor in a sealable pressure vessel where high temperatures and pressures are reached. The product is heated to a certain temperature and the melting temperature of the given bus coating is exceeded, resulting in soldering and an ideal connection of the wires. The problem is that the temperatures reached by the processor during this operation are lower than the melting temperatures of the busbar with a tin coating. In the article, the authors focus on the production and development of new types of busbars with a coating consisting of tin, bismuth and indium and discuss possible formulations and their effect on the melting temperature of the busbars.