Impact of the User Charging Practice on the Battery Aging in an Electric Vehicle

This paper studies how the user charging practice affects battery degradation over time. To achieve this objective, a system oriented simplified aging model based on the literature is proposed. The differential calculation of the capacity loss is used for infinitesimal variations. The model inputs are the battery state of charge, the battery temperature and the cumulative number of full equivalent cycles. The output is the battery state of health. This model is identified and validated with experimental aging tests from the Renault Zoe 41 kWh battery manufacturer. The battery model (electro-thermal and aging) interconnects with the vehicle traction model complete the system model. The battery electro-thermal and traction models are also validated with measurements on the studied vehicle. The Energetic Macroscopic Representation (EMR) formalism organizes in a unified way the interconnections of all the sub-system models. The impact of the charging interval and SoC on the battery aging is then studied. Five charging scenarios are studied by simulation while keeping the driving phases and the charging current the same. In these conditions, the average SoC is the main contributor for the battery aging. Compared to daily charge of the EV, a charge every 4 days extends the time to reach 80% of state of health by 36% due to lower average SoC. The daily driving distance is fixed for every studied scenario.