Adhesive film for metal terminal, method for manufacturing adhesive film for metal terminal, metal terminal with adhesive film for metal terminal, power storage device using adhesive film for metal terminal, and method for manufacturing power storage device

A method for manufacturing an adhesive film for metal terminal which is interposed between a metal terminal electrically connected to an electrode of an electrical storage device element and an exterior material for electrical storage devices that seals the electrical storage device element,

• in which the adhesive film for metal terminal includes a laminated body including, in the following order:
• a first polyolefin layer disposed on the metal terminal side, a base material, and a second polyolefin layer disposed on the side of the exterior material for electrical storage devices,
• the method includes the step of preparing a laminated body including the first polyolefin layer, the base material and the second polyolefin layer in this order,
• a sea-island structure is observed in a cross-section image acquired using a field emission-type scanning electron microscope for a cross-section of the first polyolefin layer in a direction parallel to TD and in a thickness direction,
• the cross-section image is a cross-section image acquired within a range from a surface on a side opposite to a surface on the base material layer side up to a portion at a thickness of 30% when the total thickness of the first polyolefin layer is defined as 100%,
• a ratio of a total area of island portions of the sea-island structure is 28.0% or more and 35.0% or less in the cross-section image after the adhesive film for metal terminal is left standing in a heating and pressurizing environment at a temperature of 190° C. and a surface pressure of 0.016 MPa for 12 seconds and further left standing in an environment at a temperature of 25° C. for 1 hour,
• the first and second polyolefin layers each have a thickness of 50 to 80 μm and the base material layer has a thickness of 10 to 50 μm,
• the first polyolefin layer is an acid-modified polypropylene resin,
• the second polyolefin layer is a polypropylene resin,
• the base material layer contains a homopolypropylene, and
• a deviation of particle sizes of the island portions is 0.3 or less in the cross-section image.