Battery preheating refers to a technology used when starting a new energy vehicle, especially a pure electric vehicle, to quickly raise the battery temperature so that it can reach its optimal operating temperature.
Why is battery preheating technology needed?
Both lithium iron phosphate batteries and ternary lithium batteries are affected by reduced activity of the positive and negative electrode materials and decreased conductivity of the electrolyte in low-temperature environments. This results in longer charging times and greater difficulty in fully charging the battery. During use, the battery pack depletes its power significantly faster. Therefore, to address these issues, engineers have developed battery preheating and thermal management systems. By adjusting the battery pack temperature, the impact of ambient temperature is reduced.
What are some preheating technologies?
Currently, the preheating methods for power battery packs in pure electric vehicles can be broadly divided into two types: external heating and internal heating. The former mainly uses an additional heating device to quickly heat the battery, while the latter uses alternating current to directly stimulate the chemical substances inside the battery, causing the battery itself to heat up.
External heating
1. Thermistor heating: The temperature sensing element is placed near the battery pack, so that it can serve as the heat source.
Depending on the state of the pure electric vehicle, the energy source of the preheating structure varies slightly. For example, when the owner is charging, the battery management system (BMS) monitors the battery status, including the battery pack temperature. As soon as the charging gun is physically connected, if the battery pack temperature is too low, it will use the electrical energy provided by the charging station to enter preheating mode. If the battery pack temperature is too low while driving, then the energy source is the power battery pack.
Besides the method of using thermistors to preheat the power battery pack mentioned above, another mainstream preheating method for electric vehicles on the market is electric heating film heating. Although there are obvious differences in their structural design, they are essentially the same method of using electric heating devices to generate heat and thus increase the temperature of the battery pack, which will not be elaborated on here.
2. Liquid cooling temperature control: It can cool the power battery pack at high temperatures and heat it at low temperatures to meet the overall thermal management needs of the power battery pack.
