Center Smart Materials and Adaptive Systems CeSMA
Battery cell separating layer with integrated dilation sensors
In a battery pack, the cells are usually clamped separately from each other by a functional material, e.g. to ensure uniform pressure distribution between the cells or to dissipate thermal energy during charging and discharging. As part of the SPARTACUS project, soft, silicone elastomer-based dielectric elastomer sensors are developed that act as such a functional separating layer and can simultaneously measure the expansion of the battery cell for condition monitoring. This information can be used in the battery management system (BMS) to increase the safety of the system.
Detection of cell expansion
Capacitive dilation sensors precisely measure the volume changes of the cells during charging and discharging. They also recognise irreversible and permanent volume changes caused by cell ageing. For this purpose, the sensor properties, such as their mechanical stiffness and measurement range, are adapted to the specific requirements of the battery cell.
Mechanical decoupling
Elastomers, whose compression modulus can be adjusted over a wide range, provide a uniform damping layer that separates the individual cells in a battery module and thus ensures a more even pressure distribution. In this way, pressure peaks that accelerate cell ageing can be avoided. In addition, these elastomers provide thermal shielding, which can be further optimised depending on the application.