Development of a modular lithium-ion battery for a sub-compact electric vehicle

The Technical University of Munich is currently developing the electric vehicle MUTE. MUTE is a light-weight sub-compact car, which has been presented at the Frankfurt Motor Show (IAA) 2011 as a fully functional prototype. The concept of this electric vehicle is optimized to the demands of usage in urban areas or as a secondary car. This allows a reduction to a driving distance of 100 km with a 15 kW traction system. Cost reduction as one key success criterion leads to an air-cooled battery with a downsized energy content of 10 kWh. Within our paper we want to give a detailed overview of MUTE'S design goals and the development process of MUTE'S modular lithium-ion battery system. After gathering relevant requirements for the battery system, the ideal lithium-ion cells were determined. Simultaneously to the from-scratch development of the vehicle, the battery system was constructed. Important design aspects were a durable and safe mechanical construction which is also suitable for series production. A FMEA helped to identify weak spots early in the development process. An advanced battery management and an optimized cooling/heating system for improved lifetime complete the energy storage system. The MUTE project presents an affordable and economical vehicle concept for a contemporary market introduction scenario.