The invention discloses a
power battery variable frequency heating method and device and an
electric vehicle, and relates to the battery technology, and the method comprises the following steps: obtaining a first
current amplitude according to the ratio of the difference between an upper limit
voltage and an open-circuit
voltage of equipment to the minimum impedance; taking the smaller one of thedifference between the open-circuit
voltage and the
lower limit value of the safety voltage and the difference between the upper
limit value of the safety voltage and the open-circuit voltage as minimum
polarization voltage; obtaining charge
transfer impedance when the alternating-current frequency is an upper
limit value of the alternating-current frequency according to the temperature of the battery and the impedance model; obtaining a second
current amplitude according to the ratio of the minimum
polarization voltage to the charge
transfer impedance; selecting a smallest value from the upper limit
current amplitude, the first current amplitude and the second current amplitude of the equipment as a target alternating-current amplitude; and determining a target alternating-current frequency according to the target alternating-current amplitude, and configuring
alternating current. The impedance of the non-chemical active part can be removed when the
alternating current amplitude is calculated, the calculation result is increased, and the
heating efficiency is improved.