Online parameter and state estimation of lithium-ion batteries under temperature effects

•Achieve estimation with guaranteed stability under parametric uncertainties.•Stability is guaranteed by Lyapunov's direct method.•Only voltage and current measurements are required for the estimation.•Effectiveness is validated experimentally.•Comparison against adaptive observer.

In this paper, a hybrid estimation technique is proposed for lithium-ion batteries. This strategy makes use of state-space observer theory to reduce the complexity of the design and the stability analysis. However, the battery's parameters knowledge is required for the state-space model, which limits the performance as the battery's parameters vary. Therefore, an online parameter identification strategy is proposed to track the parameters deviation. The stability of the closed-loop estimation scheme is guaranteed by Lyapunov's direct method. Unlike other estimation techniques where temperature effects are ignored, this paper proposes a universal compensation strategy which can be used with many estimation algorithms available in the literature. The performance of the proposed scheme is validated through a set of experiments under different currents and temperatures along with comparison against an adaptive observer.