LITHIUM ION BATTERY REUSE
Electric vehicles have experienced a rapid increase in demand over the last decade and will experience an even faster growth over the next decade. This will result in an increasing market for second life batteries. As per Multidisciplinary Digital Publishing Institute (MDPI), the supply of second life batteries was 1 GWh in 2020 as compared to 7 G Wh demand of lithium-ion batteries for utility scale storage. By 2025, the supply of second life batteries will reach 15 GWh per year in both base case and breakthrough scenarios. By 2030, the supply of second life batteries from EV could exceed 200 GWh/year (breakthrough scenario) and will exceed the demand of lithium-ion batteries for utility scale storage (low-cycle and high-cycle applications). Estimates suggest that USA, Europe, and China will be the major suppliers of second life batteries in the coming decade.
TESTING AND EVALUATION METHODS FOR BATTERY REUSE
Spent lithium-ion batteries have a huge potential in on-grid ESS and backup supply applications.However, there are certain technical challenges which essentially hinder the reuse of end-of-life lithium-ion batteries. The technical barriers in the entire process are highlighted below.
SAFETY TEST
Safety test and evaluation approach for second life batteries are very critical in ensuring their reuse potential in second life applications. Safety tests such as over discharging, short circuit, heating, over charging, puncturing, squeezing, etc. are typically carried out before ascertaining fitment for reuse. To further guarantee the safety of the batteries, several assessment techniques such as state of safety (SOS) and failure analysis are conducted. SOS refers to probability that a battery works safely in the given time. Failure analysis methods includes Fault Tree Analysis (FTA) and Failure Mode and Effects Analysis (FMEA). These methods can analyse risks and discover potential areas of failure in several applications.
EVALUATION METHOD
These methods obtain the performance characteristics of spent batteries and help in determining if the spent batteries are worthy of reuse. High scoring batteries can be used in reconditioning/refurbishing or in grid related ESS which are more demanding applications. Low scoring batteries can be used in forklifts or electric scooters which are fewer demanding applications.
The evaluation methods used are State of health (SOH) estimation, predicting remaining useful life (RUL), and life cycle assessment (LCA).