Evaluation of the impact of repurposing used electric vehicle batteries for residential energy storage systems

Abstract

Electric vehicles could provide a solution to several major challenges caused by the transportation sector. However, the cost of electric vehicles is a substantial barrier to overcome. As batteries make up a significant part of this cost, one solution is to create a resale value for the used battery. At the end of its life in the electric vehicle, it is expected that the battery will retain 80% of its originally manufactured capacity. This reduced capacity renders the battery unfit for automobile applications but still provides value for stationary applications such as home energy storage. Previous studies have suggested the economic benefit of home energy storage is small, but these studies also lack diversity in experimental scenarios. Therefore, this thesis proposes a varied boundary condition approach to model the environmental and economic effects of home energy storage battery reuse from electric vehicles and the additive effects of different control schemes. Some of the variations of boundary conditions in this study involve scenarios such as including solar power or the presence of an electric vehicle. Some of the varying control schemes involve repurposing home energy storage to also provide the capabilities of fast-charging electric vehicles or analyzing the self-sufficiency that this home energy storage system provides. The results from this analysis suggest the battery reuse benefits are heavily dependent on the varying scenarios and control schemes, but overall the results agree with past studies in regard to the economic benefits of home energy storage not outweighing the associated costs. However, the results also demonstrate that it is possible to significantly increase the household’s self-sufficiency and that from an economic and environmental perspective, it is far better to reuse electric vehicle batteries in lieu of new batteries for home energy storage solutions.