Novel Thin Temperature and Expansion Sensors for Li-ion Battery Monitoring

This paper introduces a combined temperature and displacement sensor for new measurements of physical parameters which can inform multi-physics based models of Li-ion batteries. These flexible sensors can be placed directly on the cell to measure intercalation effects which can improve battery state estimation. The sensors were characterized on individual Panasonic cells and subsequently, packaged into a 76 cell Ford Focus hybrid electric vehicle (HEV) pack, which was cycled for 5000 equivalent miles. Results showed improvement in temperature estimation capability with the combination of sensor and model. However, the low expansion of the hard cased cells limited utility of the eddy current sensors.