Method of manufacturing secondary battery stack

1. A method of manufacturing a secondary battery stack which is a stacked body in which secondary batteries and resin members are alternately stacked, the method comprising:

a first pressing step of pressing a resin member before being stacked with a secondary battery, in a direction in which the resin member is to be stacked, wherein the first pressing step includes pressing a flat portion of the resin member so as to compress the flat portion of the resin member in a thickness direction of the resin member, wherein a pressing force during the first pressing step is more than an upper limit of a load that is allowed to be applied to the secondary battery before causing a short circuit in the secondary battery;

a stacking step of stacking the resin member subjected to the first pressing step with the secondary battery into the stacked body; and

a second pressing step of pressing the stacked body in a stacking direction in which the secondary batteries and the resin members are alternately stacked, wherein the pressing in the second pressing step is performed with a weaker pressing force than the pressing force during the first pressing step,

wherein the resin member undergoes creep deformation during the first pressing step.

2. The method according to claim 1 , wherein the second pressing is performed on a battery surface of the secondary battery that corresponds to a region of the resin member that is pressed during the first pressing.

3. The method according to claim 1 , wherein the resin member is made of a thermoplastic resin, and during the first pressing step the resin member is heated to a range of 50-120° C.

4. The method according to claim 1 , wherein the upper limit of the load that is allowed to be applied to the secondary battery is 10 kN.

5. The method according to claim 4 , wherein a load of the first pressing step is 30 kN and a load of the second pressing step is 5.5 kN.