The Karlsruhe Institute of Technology (KIT) will present a unique modular battery concept for electric buses at the upcoming International Motor Show in Frankfurt. The battery system consists of flat modules that can be stacked to reach the dimensions and electric characteristics desired. The idea is that, because the size and shape of the battery packs are flexible, they can be easily integrated into the free space of a given vehicle.
The number of cells, and thus the length, of a single module can be varied, and any number of modules with the same length can be stacked. Within a stack the modules can be connected in parallel, series, series-parallel or parallel-series. To build larger distributed battery systems (e.g. for stationary energy storage), multiple battery packs can be connected.
Coolant can be easily passed through a cooling channel next to the conductors. Electrical connections and cooling channels are far away from the outer surface of the battery and possible impact areas. It is also possible to heat the cells using a surrounding heating mat.
The change in volume while charging and discharging a pouch cell is compensated by a compressible foam layer, which also helps to fix the cells between modules and reduces mechanical strain on the conductors.
KIT will present an e-city bus demonstrator to illustrate the concept.