Patent ID: 7971852

Claim:
A seal structure of a high-pressure tank between an opening of the high-pressure tank and an attachment member attached to the opening, comprising: a plurality of seal members having mutually different seal properties, the plurality of seal members having elasticity and being non-metallic, the plurality of seal members installed between an opening edge portion defining the opening and the attachment member, wherein: the plurality of seal members are different in temperature characteristic thereof from each other, the plurality of seal members includes a first seal member and a second seal member, the first seal member causes less leakage than the second seal member at a first temperature, the second seal member causes less leakage than the first seal member at a second temperature higher than the first temperature, the first seal member and the second seal member are different in gas permeability from each other, and the seal member having high gas permeability is positioned externally from the seal member having low gas permeability as viewed from the inside of the high-pressure tank, wherein the first seal member is formed of silicone and the second seal member is formed of EPDM in a case where the high-pressure tank is used for a hydrogen gas of 70 MPa.