Laser welding method and power storage device manufacturing method

A power storage device manufacturing method comprising:

• a step of preparing a case body having an opening on at least one side thereof;
• a step of preparing an electrode assembly having, on at least one side thereof, a current collecting tab attached with a first current collecting member;
• a step of preparing a sealing plate to be attached to the opening, the sealing plate being assembled with a second current collecting member to be welded with the first current collecting member;
• a step of accommodating the electrode assembly in the case body such that the first current collecting member is exposed from the opening of the case body;
• and
• a step of welding the first current collecting member and the second current collecting member to each other by irradiating a boundary between the stacked first current collecting member and the second current collecting member with a laser beam, wherein
• the first current collecting member and the second current collecting member each has an end face, the end faces being adjusted to the same level in height in a state that the first and second current collecting members are stacked with each other,
• one of the first current collecting member and the second current collecting member has a stepped face lower than the end face at a position away from the boundary formed when stacked with the other current collecting member,
• the other one of the first current collecting member and the second current collecting member has a stepped face lower than or higher than the end face at a position away from the boundary formed when stacked with the one current collecting member, and
• in the welding step, the boundary between the end faces of the first current collecting member and the second current collecting member is irradiated with the laser beam in a state that hoods are placed on the stepped faces of the first current collecting member and the second current collecting member, respectively.