Optimisation of weld seam configurations using a genetic algorithm

The main task of high performance electrical contacts is the transmission of electrical power with low power dissipation. The decisive value to calculate the electrical losses of a contact is the resistance of the contact configuration. The electrical resistance can be decreased applying laser welded connections. This promising joining technology offers the opportunity to vary the contact area as well as its position in the joining zone. Especially the geometrical shape of the contact area enables a high potential to reduce the contact resistance. This work presents a method to optimise the geometrical shape of the weld seam in order to minimise the resistance of the electrical contact. A solution is proposed to calculate the optimum weld seam shape by the use of a genetic algorithm (GA) linked with an electro-thermal FEM simulation. The genetic algorithm compiles alternative weld seam shapes while the FEM simulation determines their electro-thermal properties. The optimised result is further verified within an experimental study. The proposed method is applied to design the electrical contacts between battery cells of a high voltage automotive battery system for electric and hybrid electric cars.