An internal battery heating system includes an electrical conversion device electrically coupled to an electrochemical sub-cell or battery modules to form a heating circuit. The electrical conversion device alternately raises and lowers a voltage of the heating circuit to drive current between the heating circuit and the electrochemical sub-cell or battery modules. A controller commands the electrical conversion device to cyclically charge and discharge the electrochemical sub-cell or battery modules for internally heating the battery modules. Alternatively, a battery module may be electrically coupled to electrochemical sub-cells via pairs of switches to form a heating circuit. The pairs of switches are adapted for switching the heating circuit alternately between a parallel arrangement and a series arrangement to alternate charging and discharging of the battery module which results in internal heating of the battery module.