Lifetime Limitations in Multi-Service Battery Energy Storage Systems

A reliable power grid system based on renewable energy sources is a crucial step to restrict the climate crisis. Stationary battery energy storage systems (BESS) offer a great potential to repel power fluctuations in the grid at different timescales. However, for a reliable operation and cost estimation, the degradation in the batteries needs to be understood. We present an accelerated battery degradation study, on single as well as multi-service applications, of NCM532/Gr lithium-ion battery cells. Frequency regulation (FR) was the least harmful for the battery, with an expected lifetime of 12 years, while peak shaving (PS) resulted in an expected lifetime of 8 years. The combined cycle (FRPS) accelerated the capacity loss, and degradation of the positive electrode was induced from the start of cycling, causing power limitations after only 870 equivalent full cycles (EFC). Tracking the 1C-rate discharge capacity was proven to be a good indication of the accelerated cell polarization, and it can serve as a useful method to evaluate the internal battery state of health (SOH).

Automated summary

A reliable power grid system based on renewable energy sources is crucial to tackle the climate crisis. Stationary battery energy storage systems (BESS) have great potential to mitigate power fluctuations in the grid at different time scales. This study presents an accelerated battery degradation investigation on NCM532/Gr lithium-ion battery cells for single and multi-service applications. Frequency regulation (FR) was found to be the least harmful, with an expected lifetime of 12 years, while peak shaving (PS) resulted in an expected lifetime of 8 years. The combined cycle (FRPS) accelerated capacity loss and induced positive electrode degradation, leading to power limitations after only 870 equivalent full cycles (EFC). Tracking the 1C-rate discharge capacity proved to be a reliable method for evaluating the internal battery state of health (SOH).