Sensitivity Analysis of Advanced Non-Linear Observer for States Estimation of Lithium ion Batteries

Control observer-based estimation methods are getting a very rapid appreciation due to their better reliability, stability and ease of implementation in already controller-packed electric vehicles and energy storage systems. As a careful sensitivity analysis is the one vital tool to enhance the accuracy and robustness of lithium-ion battery’s states estimation, an experimental sensitivity analysis is proposed to enhance the accuracy and efficiency of battery states and parameter estimation of non-linear control observer. This paper categorically uses INR21700-M50T cells for experimental characteristic analysis of lithium-ion batteries. The results of this practical work are then used in the successful design, simulation and validation of an advanced proportional integral observer. The validated proportional-integral (PI) observer is then used to carry out the proposed sensitivity analysis, and deviations resulted in estimation accuracy due to the sensitivity of each parameter are analyzed, closely examined and dominant/highly sensitive parameter is identified based on the new estimation error statistics. Finally, the valuable insights are concluded on the need for improved identification and simultaneous estimation of dominant parameters in control observers.