According to new energy vehicle advocate Ning Xu, in the past five years, the average charging frequency of the vehicles he purchased has been twice a week in winter and three times a week in summer. Because I bought the car relatively early, it doesn’t have much mileage. In the coldest weather I can only run about 100 kilometers. Fortunately, the way to work is not too far, but if I really want to go somewhere very far, I still wouldn’t dare to drive an electric car, especially in winter. Compared with Zhang Ningxu, electric car owner Ma Jiaxin could only park her car on the side of the road, and her experience was even more miserable. If you park in the open one night and drive the next day, you will lose 20 or 30 kilometers of driving range. It was painful to watch. In order to reduce power consumption, except for children's cars, she usually did not turn on the air conditioner. Instead, she turned on the steering wheel and seat heating to ensure the warmth of the back of her hands. Not only that, she also specially prepared a thick scarf in the car to cover any cold areas.

Dai Kangwei, deputy director of BAIC New Energy Research Institute, believes that the decline in the endurance of electric vehicles in winter is closely related to the charging and discharging principles of power batteries. It is understood that when the battery is charged, the lithium ions in the positive electrode and the lithium ions in the electrolyte gather to the negative electrode and obtain electrons. The electrons are reduced to lithium and embedded in the carbon material of the negative electrode. During the discharge process, the lithium ions embedded in the negative electrode carbon material lose electrons and enter the electrolyte, and the lithium ions in the electrolyte move to the positive electrode. When the temperature is lower, the electrolyte in the battery will become more viscous, including the mobility of lithium ions and the conductivity of the material itself, which will further reduce the activity of the battery and thus affect the performance and capacity of the battery. The external manifestation is the attenuation of the available capacity of the power battery. .

However, the reduction of battery activity does not mean that the battery is damaged. If the battery capacity is compared to a container filled with water, then there will be no shortage of water when not in use. When temperatures drop, some water freezes and available water naturally decreases. During use, if the temperature rises, the ice will turn into water and can be used again. But if the temperature is always very low, the available water is only the unfrozen part. A technician in the power battery industry described the relationship between electricity and temperature. Unlike the engine of a gasoline vehicle that gradually heats up as the vehicle is driven, the battery of an electric vehicle does not necessarily heat up rapidly as the vehicle is used. The battery may still be in poor condition while the vehicle is being driven. 'Sometimes you will find that although the battery is in use, the temperature of the battery is dropping sharply. Dai Kangwei explained that because the wind flow is too large, the hot and cold exchange area of ??the entire chassis is also large, causing the battery to run. The heat is quickly released by heat exchange.

In addition to the performance of power batteries, heating is also a large consumer of electricity. According to Gu Feng, BAIC New Energy's air conditioning and vehicle thermal management technical engineer, the test vehicle is tested at -7°C, and the power consumption of the air conditioner generally accounts for 20% to 25% of the vehicle's power consumption. Dai Kangwei explained to reporters that the heat source of the air conditioning system of fuel vehicles comes from the waste heat of the engine. The conversion efficiency of the engine only accounts for about 40% of the power, and the remaining 60% of the heat conversion can fully meet the air conditioning and heating needs of the driver and passengers. However, electric vehicles do not have an engine and all heat energy needs to be obtained from the power battery. Therefore, the use of air conditioning systems has become the main source of power consumption for electric vehicles in winter.