Abstract: As a clean and efficient energy storage device, lithium-ion batteries are widely used in energy storage fields such as new energy vehicles and microgrids. However, due to its complex degradation mechanism, the cycle life of the battery itself is affected. In order to optimize the discharge capacity and cycle life based on the unspecified optimal load current, a lithium-ion battery mechanism model is adopted, and the degradation mechanism related to low discharge current is studied through charge state and cycle number. The optimal discharge current and its variation pattern for general lithium-ion batteries are determined. The research results show that when the battery is a new battery, the optimal discharge current should be maintained at the 1C level at the beginning of the discharge cycle. When the charge state SOC reaches the point where the side reaction rate in the anode significantly decreases, the discharge current should be reduced. The research results have guiding significance for the optimization operation and design of the discharge process of lithium battery modules in energy storage stations or new energy vehicles.

Key words: lithium-ion battery, capacity attenuation, low discharge rate, discharge strategy, physical model