Design of safe assembly processes for live working in traction battery series production

Live working has been done in the power supply industry for several decades now. Its focus there was on non-repeated, short-term operations like maintenance, repairs or the live connection of consumers. With the rise of electric mobility live working found its way into an automobile series production environment especially into traction battery series assembly. As single battery cells are shipped at least with a minimum charge level, they are a constant voltage source with high power during assembly. The available voltage in the workplace will increase the more the electric series connection of the traction battery is finished surpassing a critical level at some point in the process. The danger of short circuits with the possibility of electric arcs or electric shocks must then be controlled and reduced to an acceptable minimum. This paper shows an approach to the design of safe live working processes in traction battery series production starting with basic hazards and the differences of the conventional live-working environment to live working in series production. Different kinds of safety measures (technical, organizational and personal), some of them exclusive to series environment, their application and combination are then introduced. This leads to the safe work process design approach based on the concept of insulation-safe work processes and their necessary risk evaluation. The application of the concept is shown on an example. The solution is then enhanced to a version which is optimized for serial production. The application and the possibilities of the given design approach within an automated environment are also discussed.