Comparison of Li-ion battery chemistries under grid duty cycles

Li-ion batteries are the most widely deployed battery energy storage system (BESS) today but understanding the benefits and cost-effectiveness for a wide range of grid services needs to be fully validated to further expand the market. Hence, various Li-ion battery chemistries currently deployed must be evaluated and compared in terms of performance, lifecycle, economics, and safety under grid services using standardized testing protocols. In this work, commercially available cylindrical cells with four different chemistries from major Li-ion battery manufacturers are subjected to standardized tests developed by the U.S. Department of Energy Office of Electricity (DOE-OE) for frequency regulation, peak shaving, and electric vehicle drive cycles. The results of 15 months of continuous grid service tests on different chemistries are presented, analyzed, and compared in terms of capacity retention, resistance, open-circuit voltage (OCV), cyclic voltammetry (CV), incremental capacity (dQ/dV), differential voltage (dV/dQ), and AC impedance.