Process and device for forming secondary-cell gas venting hole

In the present invention, a gas venting hole is formed in a casing which houses electricity storage elements. Prior to forming the gas venting hole, the casing is secured between the periphery of the casing in which the gas venting hole is to be formed and the storage elements, and a securing force in the film lamination direction is applied to the casing. Liquid leakage when gas is vented from the casing is prevented by changing the position at which the securing force acts so that the force is directed toward the storage elements, and by reducing the securing force as the position at which the securing force acts approaches the storage elements. 在容纳有蓄电元件的壳体上形成排气孔。在排气孔的形成之前，在形成排气孔的壳体的周缘与蓄电元件之间将壳体夹持，对壳体施加薄膜贴合方向上的夹持力。使夹持力的作用位置朝着蓄电元件的方向变化，并且使夹持力随着夹持力的作用位置接近蓄电元件而减弱，藉此来防止排气时从壳体漏液。