Electrochemical Properties of Soft-pack LiFePO4 Battery after High-temperature Float Charge
LiFePO4 battery has attracted much attention in the field of energy storage due to their safety.Floate-charging is a common charging method to supplement battery energy.It is particularly important to study the influence of different floate-charging conditions on battery performance.In this paper,the high-temperature (50 ℃) float-charging test is carried out on the soft-pack LiFePO4 battery with the rated capacity of 21 A·h,to explore the influence of different float-charging voltages (3.40 V,3.65 V and 3.85 V) on the battery capacity,discharge rate performance,temperature field distribution,mixed power pulse characteristics and other performance under high-temperature.The results show that after float-charging,the capacity retention rate of the battery decreased sharply,and the capacity retention rate is lower than 80％ after 60 days.With the increase of float-charging voltage,the capacity retention rate decreased sharply,and the influence of float-charging voltage difference at high-temperature increased significantly.After the high-temperature float-charging,the active materials and active lithium ions of the battery are seriously lost,the kinetics of the interface reaction is hindered,the internal resistance of the battery increases significantly,and the battery discharge pulse power capacity decreases.These aging phenomena accelerated with the increase of float-charging voltage.The research on temperature field distribution shows that the highest temperature of the battery during discharge occurs at the positive electrode lug after high-temperature float-charging.At the same time,the battery discharge rate capacity decreases significantly after float-charging,and the discharge capacity decreases with the increase of the rate,and the temperature rise at the corresponding point increases significantly.Due to the aging and temperature rise of the battery after high-temperature float-charging,long-term high-temperature float-charging should be avoided in the use of the battery.A reference for the floate-charging strategy of LiFePO4 energy storage battery is provided.
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维普
