What is the impact of low temperature on new energy vehicles?

In the low temperature environment, the actual capacity, discharge rate and voltage platform of the power battery system will be reduced, which will affect its performance on the whole vehicle, such as the reduction of cruising range and maximum discharge power. These parameters will affect the estimation of SOC of battery management system and the definition of safety policies such as overcharge and overdischarge.

The development of pure electric vehicles mainly depends on the progress and development of power battery technology. From the development of battery types, it has experienced three times: lead-acid battery, nickel-hydrogen battery and lithium-ion battery.

Lithium-ion batteries have become the mainstream of the times because of their long life, high rate, high energy density and pollution-free, while nickel-cobalt-manganese ternary lithium batteries and lithium iron phosphate batteries have been widely used for their high energy density and low cost. However, the electrochemical performance of lithium-ion batteries is closely related to the performance of cathode materials, electrolyte, conductive agent and binder.

In low temperature environment, the activity of anode and cathode materials, the permeability of electrolyte and the performance of binder will all decrease, so the electrochemical performance of lithium-ion battery will decrease sharply with the decrease of temperature.

In the low temperature environment, the actual capacity, discharge rate and voltage platform of the power battery system will be reduced, which will affect its performance on the whole vehicle, such as the reduction of cruising range and maximum discharge power.

These parameters will affect the estimation of SOC of battery management system and the definition of safety policies such as overcharge and overdischarge.

Aiming at a light commercial electric vehicle equipped with lithium ferrous phosphate power battery system, the performance of its power battery system in low temperature environment is studied, which provides the basis for the low temperature strategy of battery management system.

1 Effect of low temperature on charging aging Due to the degradation of electrochemical performance of lithium iron phosphate power battery at low temperature, it cannot be charged or discharged or its charging and discharging efficiency is reduced. In order to solve this problem, the power battery system uses a thermal management system to heat the battery pack, so that the battery core works in the optimal temperature range.

(Photo/Text/Photo: Pacific Auto Network Q&A called Beast)