The invention discloses a low-temperature self-heating method of a
lithium ion battery pack. The low-temperature self-heating method comprises the steps of determining an optimal heating frequency range compatible with a battery aging state and state-on-charge (SOC) according to a principle of minimum influence on lifetime of a battery; designing a series resonant inversion circuit, and exploring an
optimal control strategy so that the inversion circuit outputs a sine
AC current of a target frequency and target amplitude at a battery side; and performing low-temperature self-heating on the
battery pack by the sine
AC current output from the resonant inversion circuit, wherein the
internal resistance of the battery is gradually reduced with the temperature rising of the battery, the output
current amplitude of the resonant inversion circuit is adaptively increased, the heating rate of the
battery pack is improved, and the battery pack is rapidly raised to a target temperature. The low-temperature self-heating method has the effects of fast self-heating rate on the
lithium ion battery pack under a low temperature, obvious improvement on low-temperature performance, high self-
heating efficiency, no influence on service lifetime of the
lithium ion battery, good
heating temperature uniformity and the like, and the promotion and the application of an
electric vehicle in a cold place are facilitated.