Pulse preheating has been introduced as a method to improve the performance of lithium-ion batteries in cold ambient temperatures. Pulse preheating involves applying a series of high-current pulses to the battery to quickly raise its temperature to an optimal operating range.
Lithium-ion batteries, which are extensively used in electric vehicles (EVs) face challenges in cold environments. As the temperature decreases, the performance of the battery declines due to the slowdown in the movement of lithium ions, which adversely affects the power output and the energy efficiency of the device. The battery's internal resistance increases due to a decrease in electrolyte conductivity and a slower lithium-ion intercalation process in the anode. Further, continuous battery operation in these conditions can accelerate lithium plating, which can lead to a short circuit and reduce the battery's lifespan.
In pulse preheating, short, high-current pulses are passed through the battery. The application of these pulses causes an instantaneous internal reaction, generating heat within the battery. This heat is then utilized to raise the temperature of the battery, thus lowering the internal resistance and enhancing the conductivity of the electrolyte.
Pulse preheating can also potentially extend the life of the battery. By rapidly heating the battery to its optimal operating temperature, the risk of lithium plating caused by extended exposure to low temperatures is minimized. This can lead to an improved battery lifespan.
Considerations in Implementing Pulse Preheating:
While pulse preheating has shown promise to the researchers, certain factors need to be considered in its application. The intensity, duration, and frequency of the pulses must be controlled to avoid overstressing the battery, which could lead to thermal runaway. Further, the method and effectiveness of heat dissipation need to be considered to maintain an optimal temperature once the preheating phase is complete.