The present application discloses a heating module, a heating method for a battery module, and a heating system. The heating module includes: an energy storage unit, a first switch unit, a second switch unit and a control unit. The energy storage unit, a first battery unit in a battery module and the first switch unit may form a first heating loop; the energy storage unit, a second battery unit in the battery module, and the second switch unit may form a second heating loop. The control unit may control the first switch unit or the second switch unit, so as to sequentially switch on, between the first heating loop and the second heating loop, a heating loop where a battery unit with a higher state of charge is located and a heating loop where a battery unit with a lower state of charge is located, so that the battery module is in a state of being continuously charged and discharged and the battery module is heated by electric energy generated during continuous discharging and charging.