Remaining useful life prediction of Lithium-ion batteries of stratospheric airship by model-based method

Lithium-ion battery has become one of the key components of energy system of stratospheric airships for its long service life, higher energy and power density. However, battery ageing always occurs during operation and leads to performance degradation and system fault which not only causes inconvenience, but also risks serious consequences such as thermal runaway or even explosion. So it is necessary for users to obtain the time left before the battery loses its operation ability. This paper uses model-based approach to estimate the remaining useful life (RUL) of the battery used in stratospheric airship. The acquisition dataset containing voltages and currents is firstly processed by subspace identification method, and then an equivalent circuit model is set up. The values of capacitances and resistances within the circuit are identified to indicate the battery's degradation in capacity and internal resistance.