Vitesco & German government to develop battery warning systems
Together with Vitesco Technologies, the German Federal Institute for Materials Research and Testing (BAM), is developing an early warning system for electric car batteries that is intended to indicate possible damage to the battery at an early stage. Previous warning systems register damaging changes in the batteries via sensors that react to suspicious changes in temperature or pressure within the battery.
The disadvantage of this kind of system is that the alarm is only triggered when the battery is already damaged. Thermal runaway and thus probably the complete destruction of the battery are usually unavoidable at this point. In cooperation with Vitesco Technologies, BAM is now researching a warning system that should indicate critical changes in individual battery cells earlier and thus help to avoid total loss. The basis for this is a procedure that continuously measures and analyses the electrical alternating current resistance, the impedance, in the cell.
Until now, long measurement times have been necessary for meaningful impedance analyses. They prevent the implementation of such analyses in a BMS. The innovative approach of the project team: It modifies the measurement methodology so that a high acceleration in recording and processing the impedance data is possible.
“A change in impedance can indicate various defects or undesirable conditions,” explained Tim Tichter, who is conducting research at BAM as part of the project. “These can be caused, for example, by vibrations, shocks, thermal loads, material failure or even manufacturing defects. Regardless of the respective cause, however, a change in impedance is to be expected in any case.”
bam.de (in German)