Testing and Optimization of Flexible Pressure Sensors for the integration into battery cells: A Drop Casting Approach with Piezoresistive Elastomers

We present a simplified manufacturing process, where flexible pressure sensors are produced employing a paste of graphene nano platelets in a polymer matrix, that is drop casted on a flexible polyimide sheet with an electrode pair. For that the influence of the amount of solvent and graphene and the type of the matrix material are investigated. The sensors were characterized by resistance measurements in dependence of the applied pressure. The results of manufacturing and characterization show a clear dependence of the sensitivity on the viscosity of the paste, rather than on the amount of graphene and the type of polymeric material. Knowing this, the operation range and the precision of the sensors can be customized to the application. Maximum sensitivities of 0.0023 to $0.000751 / \mathrm{KPa}$ could be achieved at a coefficient of determination of 0.99. The devices also proof precise results in a long-term stability test over 14 days.