Low-cost Systems to Measure the Volume Variation of Lithium-ion Cells

Lithium-Ion batteries are the preferred solution for energy storage in many application fields. However, they can lead to hazardous situations and accidents when used outside their safety area. The development of early fail detection mechanisms is mandatory. One of the most promising is the measurement of the mechanical deformation of battery cells. It provides information about their internal state and allows one to early detect the possible fault of a battery. An optical and an inductive low-cost measuring systems are investigated in this work. The systems have been characterized and then used to estimate the mechanical expansion of an aged 20 A h NMC cell under various operating conditions. The results show a good measurement accuracy and highlight a correlation between cell volume and its internal state.