Model-based Lifetime Analysis of 2nd-life Lithium-Ion Battery Storage Systems for Stationary Applications

Abstract

For determination of battery storage business cases key decision criteria are lifetime and State of Health (SoH), in addition to investment costs, operating costs and revenues. The lifetime and SoH strongly depend on operating conditions, such as number of equivalent full cycles (EFC), operating battery cell temperature, Depth of Discharge (DoD), C-rate and State of Charge (SoC). Those can vary depending on operating strategy and chosen application. In this analysis the lifetime of 2^nd-life lithium-ion (Li-ion) battery energy storage systems (BESS) are examined and evaluated, depending on various stationary applications. Avoiding the expenses for battery cell parameterization, an improved methodology based on weighted Ah-Throughput (AhTp) and Fuzzy Logic is used to apply qualitative statements of experts into quantitative values. The investigation is carried out by using MATLAB Simulink including application-related load profiles. Based on the results statements for lifetime expectations are given.