SOC Estimation Method of Lithium Ion Battery for Contact Wire and Battery Hybrid Electric Railway Vehicle

Railway vehicles are increasingly being equipped with secondary batteries to improve energy saving performance and sustainability. To manage battery energy, it is necessary to have accurate and stable state of charge (SOC) estimation. In this paper, the authors report on a stable SOC estimation method for on-board lithium ion batteries developed for the contact-wire and battery hybrid electric railway vehicle. Parameters such as battery capacity and inner resistance can be automatically tuned via this estimation method. The authors report on results from performance verification running tests with JR-Shikoku. Their estimation results indicated sufficient performance for practical use, and the inner resistance and battery capacity parameters were also properly estimated through the running tests.