Development of Wire Bonding as a Joining Technique in Battery Packs

The automobile industry is switching to electric powered vehicles to minimize carbon (and its oxides) emissions and the amount of air pollution that is brought due to these emissions. A big section of the electric vehicle industry is battery technology. Automotive battery packs consist of a range of battery cells of different form factors that are interconnected in series and parallel connections to shape modules and then connected collectively to form battery pack. These cells are structurally held and electrically connected to each other by means of a joining technique. To enhance the quality, design and to reduce the weight and cost of the battery pack it is very important to choose an appropriate joining technique. These techniques could be spot welding, laser welding, nut / bolt joining or ultrasonic wire bonding. The current work offers an overview of applied sciences for battery manufacturing with merits and demerits. Apart from this a Pugh matrix approach was considered to rate the process. A battery pack was designed and fabricated to evaluate the bonding operations and testing. The parameter at which pull off load is achieved and there are no mechanical stresses is determined and is chosen as the optimized bonding parameter. The cycle time can be decreased by 2.48% and the cost to manufacture the battery pack can be reduced by 38.2% by adapting to ultrasonic wire bonding when compared to traditional resistive spot welding.