A computationally efficient adaptive online state-of-charge observer for Lithium-ion battery for electric vehicle

•The Lyapunov based adaptive observer is proposed to estimate SOC for Lithium-ion batteries.•In addition to guaranteed stability, the observer has simple structure with only a few recursive equations.•The experimental test on a 3 Ah battery using dynamic stress test (DST) proves the proposed observer's efficiency by achieving 0.928% mean absolute error.•The advantage of the proposed method is confirmed by reducing the computational cost by approximately 2.5 times compared to EKF-RLS, while attaining close accuracy.