Second-use applications of lithium-ion batteries retired from electric vehicles: Challenges, repurposing process, cost analysis and optimal business model

The lithium-ion (Li-ion) battery of high power density and large electricity capacity is pioneering both uncultivated lands, the electric vehicle (EV) for driving longer distances, and the electricity storage system (ESS) for storing huger amount of electricity. Still, the high capital cost of Li-ion battery, around 50% of an EV, currently impede the universal market adoptions of EV and ESS industries. Through a sophisticated repurposing process and a clever business operation, the used Liion batteries retired from EV usually holding residual 70 ~ 80% electricity-storage capacities can create long-term and stable profits from proper second-use or repurposing applications, such as the electricity-storage batteries of an ESS for storing the electricity from renewable energy systems. From the viewpoint of environment protection, this transforming movement firmly meets with the 'eco-3R' principles of recycle, reuse and reduce. During the 'pre-recycling' period of second-use application, more creative technologies to dispose of the large-sized and unable-to-reuse Li-ion batteries can be developed. A complete eco-life of an EV Li-ion battery can be achieved. In this research, the critical issues are explored, including challenges, repurposing processes, cost analyses, and optimal business models for transforming a used Li-ion battery pack retired from EV into ESS for its second-use application. The estimated profit rate of a case study can reach around 39%; namely, a 10kWh Li-ion battery pack of 20-year calendar life primarily works in EV for 5 years, and then runs in ESS for following residual 15 years.