Experimental study on lithium-ion cell characteristics at different discharge rates

Clarifying the relationship between the characteristics of lithium-ion battery and the discharge rate is beneficial to the battery safety, life and state estimation in practical applications. An experimental analysis to study lithium-ion battery cell characteristics at different discharge rates is presented. Based on constant current discharge experiments and hybrid pulse power characteristics experiments, discharge rate effects on cell thermal characteristic, capacity characteristic and electrical characteristic are analyzed. Studying the changing rules of characteristics and revealing their relevance. Results show that when the discharge rate is in the range of 0.5C to 4C, the temperature rise rate accelerates with the increase of the discharge rate. The highest surface temperature rise at the center of the cell is 44.3°C. The discharge capacity drops sharply at high rates, up to 71.59%. Both internal resistance and voltage decrease as discharge rate increases. The thermal characteristic, capacity characteristic and electrical characteristic of the cell change dynamically and influence each other. The cell characteristic changes and characteristic correlations are explained to provide a detailed and broader understanding of the lithium-ion battery operating scenarios at different discharge rates.