Second Life for Lithium-Ion Traction Batteries

Abstract

For the reuse of traction batteries, many different scenarios exist, for example, stationary storage farms or fast charging stations. Another second-life usage scenario is the reuse of batteries as home energy storage in combination with a photovoltaic installation in a private household. This application is the focus of the present study. Home energy storage is a reasonable possibility for storing renewable energy and conserving resources, but it also includes multiple challenges regarding reliability and safety requirements. Within this study, these challenges are investigated. A battery inspection concept was developed, and a logistic model for considering the legal requirements was created. Data from different use cases were selected, and their structure was homogenized. To assess their safety, fire tests were performed. In addition, a concept for a reliability assessment that provides the possibility to evaluate the suitability of a battery for a second-life application based on usage data in its first life was developed. Based on the results, a prototype of a second-life storage system was built from traction battery cells removed from electric vehicles. This prototype is currently used to store energy from a photovoltaic system, and its usage data were collected.