Battery pack manufacturing method

A manufacturing apparatus of a battery pack which includes a cell stack that is a stack of a plurality of single cells and a cooler that includes a refrigerant flow passage, and in which a cooled portion that is at least a part of a surface of the cell stack extending along a stacking direction of the single cells is attached to the cooler, with a viscous body layer interposed between the cooled portion and the cooler, the manufacturing apparatus comprising:

• a viscous body layer forming device configured to form the viscous body layer on the cooler by discharging a viscous body from a nozzle, an opening of a discharge port of the nozzle being in an arc shape having a central angle within a range of 10° to 35° toward a downstream side in a film formation direction in forming the viscous body layer;
• and
• an attaching device configured to attach the cell stack to the cooler while pressing an opposed surface of the viscous body layer facing the cooled portion of the cell stack with the cooled portion, before hardening of the viscous body layer on the cooler is completed.