A new joining by forming process for busbar-prismatic cell interconnections in electric vehicle batteries

Abstract The paper introduces a new joining process, termed tube fit joining, designed for prismatic cell terminal-to-busbar connections in electric vehicle batteries. In this process, a tubular connector is inserted into the terminal and busbar holes and deformed to create a force- and form-fit joint. This joining technique enables the connection of dissimilar materials without heating, reduces the joint’s weight, and facilitates easy disassembly for maintenance, reuse, or recycling. The study begins by analyzing the tube fit joining process through finite element simulations, examining the influence of geometric parameters, materials, and friction conditions. A specialized tool was then developed to implement the process, and various joints were manufactured for comparison. The joints underwent mechanical and thermal-electrical testing to evaluate performance under conditions simulating real-world service. The results indicate that increasing the connector’s diameter and length enhances both force-fit and form-fit properties, improving mechanical performance and achieving a strength of approximately 750 N. However, to enable easy disassembly, the force-fit severity must be carefully controlled to ensure safe separation of the components. The thermal-electrical analysis further validated the effectiveness of the joint, showing a joint resistance of 20–25 µΩ. The findings demonstrate the feasibility of the tube fit joining process for interconnecting prismatic cells through busbars in electric vehicle batteries.