A battery pack in an EV consists of a large number of individual battery cells that are held together mechanically and connected electrically. Making those mechanical and electrical connections poses several challenges, including the joining of multiple thin, highly conductive materials of varying thicknesses and potential. The key aim for the electrical connections is to produce a joint with a low electrical resistance to reduce the energy loss through resistance. A battery pack has to use different materials, and this creates a challenge for joining dissimilar materials. It can create brittle intermetallic layers with higher electrical resistance and a. Resistance spot-welding (RSW) exploits the electrical resistance at the mating surfaces when high current passes through them to create localised heating and fusion of materials. Nevertheless, ultrasonic metal welding is one of the most commonly used methods. It has been used for various electric cars, including the Nissan Leaf.
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“We see a lot of laser welding and ultrasonic wedge bonding for the larger packs,” says Boyle at Amada Weld Tech. “If the packs or the overall volume are smaller, then resistance welding is often used. Micro-TIG comes up for specialised battery packs with low-volume production.
How do I choose the right battery pack welding technology?
Selecting the appropriate battery pack welding technology to weld battery tabs involves many considerations, including materials to be joined, joint geometry, weld access, cycle time and budget, as well as manufacturing flow and production requirements. Fiber laser welding
How are battery cells welded?
Different welding processes are used depending on the design and requirements of each battery pack or module. Joints are also made to join the internal anode and cathode foils of battery cells, with ultrasonic welding (UW) being the preferred method for pouch cells.
What is a battery pack welding application?
Whether to power our latest portable electronic device, power tool, or hybrid/electric vehicle, the removable battery pack is essential to our everyday lives. Tab-to-terminal connection is one of the key battery pack welding applications.
Why is welding important for EV battery systems?
Welding is a vitally important family of joining techniques for EV battery systems. A large battery might need thousands of individual connections, joining the positive and negative terminals of cells together in combinations of parallel and series blocks to form modules and packs of the required voltage and capacity.
Which welding methods can be used for battery assembly?
Other joining methods such as micro-tungsten-inert-gas welding (micro-TIG), micro-clinching, soldering, and magnetic-pulse welding exist and have been proposed for battery assembly applications, but they are not well established, and therefore their feasibility is still being evaluated, or they are not widely used in the industry.