Preliminary Demonstration of Internal State Estimations for Batteries in an in-Service EV Using a Nondestructive Diagnosis Technique

Kenichiroh Koshika (NTSEL)･Tomokazu Morita (TOSHIBA)･Toshiki Oda (KANSAI ELECTRIC POWER)･Keizoh Honda (JET)

Internal state estimations for traction batteries in an in-service EV (manufactured in 2013) using charging curve analysis as a nondestructive diagnosis technique has conducted. We revealed the range of SOH estimation results depending on differences in data sampling methods and analysis methods. The characteristics of battery degradation were also classified based on the estimated internal state of batteries.

Estimation of Battery Pack SOH Based on Non-Destructive Diagnostic Technique for Cell Capacity and Cell Balance During Battery Pack Degradation

Tomokazu Morita (Toshiba)･Keizoh Honda (Japan Electrical Safety & Environment Laboratory)･Kenichiroh Koshika (National Traffic Safety and Environment Technology Laboratory)

A cycle degradation test was conducted on a 7-cell series battery pack using automotive lithium-ion batteries. At regular cycle intervals, non-destructive diagnostics were performed using charge curve analysis. The degradation state of the pack was evaluated by estimating individual cell capacities, internal states, and cell balancing conditions. The overall State of Health (SOH) of the battery pack was then calculated. Finally, the estimated SOH was compared with the measured capacity to verify the accuracy of the diagnostic method.

Study on Improving Cycle Durability of Anode-free All-Solid-State Batteries (First Report)

Takashi Nakagawa･Kyohei Izumi･Shuntaro Ujiie･Hayate Kusushita (Honda R&D)

Degradation analysis of anode-free all solid-state batteries and improvement of charge-discharge cycle durability by improving the specification of anode current collection foil will be reported.

A Power Control Method Utilizing Pre-Operational Information to Extend the Lifetime of Fuel Cells in a Fuel Cell Hybrid Test Train

Takashi Yoneyama (Railway Technical Research Institute / Waseda University)･Sihai Xu･Shengen Hsu･Minhao Wen･Yida Bao･Wei-Hsiang Yang･Yushi Kamiya (Waseda University)･Kenichi Ogawa･Takamasa Yamada･Manato Kaneko (Railway Technical Research Institute)

This study proposes an output power control method for a fuel cell hybrid test train that utilizes pre-operational information such as track gradient and passenger load factor. While conventional methods rely solely on the current state of the train—such as the battery state of charge (SOC) and traction converter output—as inputs for control, the proposed method incorporates pre-operational information into the control strategy. The impact of the method on fuel cell degradation is quantitatively calculated through a simulation.

Investigation of Impedance Measurement Methods for EV Traction Batteries Mounted on EVs

Takumi Mori･Nozomu Teranishi (HIOKI E.E. CORPORATION)･Toshimichi Takahashi (Meidensha)

It is important to establish and standardize a method to measure and evaluate the electrical characteristics of EV traction batteries mounted on EVs as an inspection methodology for EV performance and safety. In this study, multiple methods for measuring the internal resistance/impedance of battery packs mounted on EVs were evaluated. The experiment results and comparative investigation is reported, to propose an appripriate and versatile method.