A DC/DC conversion circuit for a charging pile, wherein the DC/DC conversion circuit comprises: a first convertor module, wherein an input end of the first convertor module is configured to connect to a power grid through an AC/DC conversion circuit; a transformer module, wherein an input end of the transformer module is connected to an output end of the first convertor module; an energy storage module; and a second convertor module, wherein an input end of the second convertor module is configured to connect to one of an output end of the transformer module and the energy storage module, and an output end of the second convertor module is configured to connect to a battery pack of an electric vehicle when the charging pile is charging the electric vehicle; characterized in that when a first frequency range is required to heat the battery pack, the second convertor module is configured to connect to the transformer module and perform charging and discharging between the power grid and the battery pack within the first frequency range to heat the battery pack, and when a second frequency range is required to heat the battery pack, the second convertor module is configured to connect to the energy storage module and perform charging and discharging between the energy storage module and the battery pack within the second frequency range to heat the battery pack, wherein the frequency required to heat the battery pack is a number of charging and discharging cycles of the battery pack periodically performed during a unit of time, wherein the first frequency range is lower than the second frequency range; wherein the energy storage module is an energy storage inductor or an energy storage capacitor. a first convertor module, wherein an input end of the first convertor module is configured to connect to a power grid through an AC/DC conversion circuit; a transformer module, wherein an input end of the transformer module is connected to an output end of the first convertor module; an energy storage module; and a second convertor module, wherein an input end of the second convertor module is configured to connect to one of an output end of the transformer module and the energy storage module, and an output end of the second convertor module is configured to connect to a battery pack of an electric vehicle when the charging pile is charging the electric vehicle; characterized in that when a first frequency range is required to heat the battery pack, the second convertor module is configured to connect to the transformer module and perform charging and discharging between the power grid and the battery pack within the first frequency range to heat the battery pack, and when a second frequency range is required to heat the battery pack, the second convertor module is configured to connect to the energy storage module and perform charging and discharging between the energy storage module and the battery pack within the second frequency range to heat the battery pack, wherein the frequency required to heat the battery pack is a number of charging and discharging cycles of the battery pack periodically performed during a unit of time, wherein the first frequency range is lower than the second frequency range; wherein the energy storage module is an energy storage inductor or an energy storage capacitor.