A battery module, comprising: a plurality of battery cells; and a heating sheet, wherein, two adjacent battery cells are in contact with each other, and a gap region is defined between side walls of the two adjacent battery cells; the heating sheet comprises a plurality of heating units and a plurality of connection units, two adjacent heating units are coupled with each other through a connection unit, a heating unit is attached to a side wall of a battery cell, and the connection unit corresponds to the gap region; the heating unit comprises an insulating film and a heating wire laid on the insulating film, and the heating wire has an inflow end and an outflow end; the connection unit comprises a first connection film and a first conductive wire laid on the first connection film, the outflow end of the heating unit is electrically coupled with the inflow end of an adjacent heating unit through the first conductive wire, and two insulating films of the two adjacent heating units are connected with each other through the first connection film; and the first conductive wire has a routing density less than the heating wire, or the first conductive wire has a cross-sectional area larger than the heating wire, such that the connection unit has a heat productivity per unit area less than the heating unit; wherein the heating sheet is implemented as two heating sheets; and the two heating sheets are attached to two opposite side walls of the battery cell respectively, and the heating wires of the two heating sheets are coupled with each other through a second conductive wire; and wherein the second conductive wire has a cross-sectional area larger than the heating wire. a plurality of battery cells; and a heating sheet, wherein, two adjacent battery cells are in contact with each other, and a gap region is defined between side walls of the two adjacent battery cells; the heating sheet comprises a plurality of heating units and a plurality of connection units, two adjacent heating units are coupled with each other through a connection unit, a heating unit is attached to a side wall of a battery cell, and the connection unit corresponds to the gap region; the heating unit comprises an insulating film and a heating wire laid on the insulating film, and the heating wire has an inflow end and an outflow end; the connection unit comprises a first connection film and a first conductive wire laid on the first connection film, the outflow end of the heating unit is electrically coupled with the inflow end of an adjacent heating unit through the first conductive wire, and two insulating films of the two adjacent heating units are connected with each other through the first connection film; and the first conductive wire has a routing density less than the heating wire, or the first conductive wire has a cross-sectional area larger than the heating wire, such that the connection unit has a heat productivity per unit area less than the heating unit; wherein the heating sheet is implemented as two heating sheets; and the two heating sheets are attached to two opposite side walls of the battery cell respectively, and the heating wires of the two heating sheets are coupled with each other through a second conductive wire; and wherein the second conductive wire has a cross-sectional area larger than the heating wire. the heating sheet is implemented as two heating sheets; and the two heating sheets are attached to two opposite side walls of the battery cell respectively, and the heating wires of the two heating sheets are coupled with each other through a second conductive wire; and wherein the second conductive wire has a cross-sectional area larger than the heating wire.