Battery pack with enclosed heater

A battery pack comprising:

• a cell stack including a plurality of battery cells arrayed in one direction;
• a housing case housing the cell stack;
• and
• a heater configured to increase temperature of the battery cells, wherein
• the heater being arranged on top of a bottom part of the housing case inside the housing case such that the heater is separated from a cell bottom part of the battery cell vertically downwardly,
• a space between the bottom part of the housing case and the cell bottom part of the battery cell being a closed space in a section in a direction orthogonal to an array direction of the plurality of battery cells,
• a recessed heater installing part is provided in the bottom part of the housing case, the recessed heater installing part includes a heater installing member that includes a base part on which the heater is arranged and a pair of bottom plate parts extending from a lower surface on both sides of the base part in a direction parallel to the array direction of the battery cells, and upper surfaces of the bottom plate parts facing the closed space are positioned lower than an upper surface of the base part on which the heater is arranged,
• in the section in the direction orthogonal to the array direction of the battery cells, stack support parts on both sides of the recessed heater installing part support the cell stack in a state of being in contact with the cell bottom part of the battery cell such that the closed space is defined, and
• an elastic body is interposed in a contact part between the stack support part and the cell bottom part.