ENERGY DENSITY VERSUS SAFETY
If, say, you substantially raise the nickel content, the cell’s energy density will increase. But that has its drawbacks in terms of safety. “The cell then reacts more dramatically when something happens,” says Wilstermann, summing up the consequences of such a step. The appropriate precautionary measures start with getting the arrangement and cooling of the cell right and end with the specially designed housing.
It’s all a question of fine-tuning. Making improvements at one point can potentially be to the detriment of something else, meaning you have to adjust again. Once again it sounds straightforward, but once again it is complex – particularly if the cells, as in the Accumotive battery, are packed tightly together in order to achieve a higher energy density than competitors’ batteries. This is a more complex approach if you also want to guarantee safety under all conditions.
HYBRID, ELECTRIC, PLUG-IN
There will be no such thing as a universal battery in the future either. Unlike conventional drive systems, whose technically identical engines can be transplanted into various models with relative ease, Wilstermann develops “made-to-measure batteries for the different Daimler vehicles. For example, we use cells that are geared towards performance in the hybrid models and cells geared towards capacity in the electric vehicles. The batteries for the plug-ins lie somewhere in the middle.”
The developers in Nabern bring together the defined requirements of the model, the installation space and the costs, and these criteria, in turn, are critical to the chemical composition of the respective power cells. Also, the battery in the new model needs to be assembled and cooled in such a way that all Mercedes-Benz models work perfectly in every kind of weather zone. “There’s no ‘absolute best’ with us, but simply the best compromise for a particular application,” says Wilstermann.