Life Degradation of Lithium-Ion Batteries Under Vehicle-to-Grid Operations Based on a Multi-physics Model

The bidirectional charging method with active control between electric vehicles (EVs) and energy grids, known as the Vehicle-to-Grid (V2G) method, is a technology gaining attention for its potential to improve energy efficiency. However, concerns have been raised about the rapid decrease in the lifespan of lithium-ion batteries due to their increased usage with the V2G method. This study evaluates the effects of the V2G method on the lifespan reduction of lithium-ion batteries (LIBs) using a physics-based model. The degradation of LIBs was simulated under both conventional unidirectional charging methods and the V2G method. The model results demonstrated that the V2G method does not negatively impact battery lifespan compared to unidirectional charging. In fact, it can even mitigate the reduction in lifespan. Specifically, this study found that the degradation with the V2G method was 39%, which is better than the approximately 44–48% observed with unidirectional charging methods. Additionally, the model results indicated that the state of charge (SOC) during charging and resting periods of LIBs significantly impacts lifespan reduction. This study suggests that it is possible to enhance the lifespan management of EV LIBs using the V2G method by minimizing SOC levels during the charging process.