Heat preservation system and heat preservation method of power battery

The invention relates to a heat preservation system of a power battery. The system comprises an air supply device which communicates an automobile carriage with a battery cabin for accommodating the power battery and feeds air in the carriage into the battery cabin, and a temperature controller for monitoring the temperature in the battery cabin and controlling the air supply device to supply air according to a monitored temperature and the working state of an electric automobile. The air supply device communicates the carriage of the electric automobile with the battery cabin for accommodating the power battery, and the temperature controller monitors the temperature in the battery cabin, controls the air supply device to introduce cold and warm air produced by the conventional air conditioner of the electric automobile in the carriage into the battery cabin according to the monitored temperature and the working state of the electric automobile and heats or cools the power battery for preserving heat, so that the temperature of the power battery does not influence normal work, the electric automobile can run normally, the popularization and application of the electric automobile are promoted greatly, and environmental protection and emission reduction are facilitated.