Allocative efficiency of high-power Li-ion batteries from automotive mode (AM) to storage mode (SM)

Lithium-ion phosphate (LFP) batteries are utilized in many fields because of their great value in high security, high-current discharge, and cycle life. LFP batteries are used in two primary modes: Automotive mode (AM) and Storage mode (SM). AM is frequently used in pure EV or electric tools. SM has been commonly employed in UPS or energy storage systems. Owing to the impact caused by higher operating current, the cycle life performance in AM may decay faster than in SM. Generally, after two years of use in AM, the capacity and operating voltage retention are lower than 70%, and it is no longer enough to start an electric vehicle or device which may still work in storage systems. We investigated a two-phase model from AM to SM, and seven 60 Ah batteries with different compositions were tested under various conditions. Data Envelopment Analysis (DEA) was used to evaluate the best shift point from AM to SM. The experiment was affected by six factors: AM/SM capacity decay, price per kWh, electrical conductance, total kWh generated, and SOH%. Considering all conditions and a price sensitivity analysis from 2009 to 2022, the battery was used in a 1:1 ratio (time in AM to time in SM) to maximize its value.