State-of-health estimation for satellite batteries based on the actual operating parameters – Health indicator extraction from the discharge curves and state estimation

Feasible state-of-health (SOH) estimation methods based on measurable parameters, such as voltage, current, time and temperature, are still urgent for batteries used in satellites. Particularly, the satellite batteries are often operated with shallow depth-of-discharge, e.g. 20% or 30%, and the current is approximately consistent. In this paper, we propose a novel health indicator based on the discharge curves. The effects of depth-of-discharge, current and temperature on the health indicator are investigated. Then, the health state of batteries aged with different rates and depth-of-discharge is characterized based on the novel health indicator. The characterization results show that there is some linearity between the maximum available capacity and the proposed health indicator. An empirical model is presented and the SOH of batteries operated with different regimes is estimated. The satisfying estimation results with a maximum error of 4% (most of the errors are less than 3%) suggest that the novel health indicator is effective and feasible for SOH estimation of satellite batteries.