In one aspect, a variable volume vessel includes an expandable/contractable bellows along with one or more components and/or features that prevent over-travel of the bellows and/or that prevent binding of the bellow relative to an outer housing of the vessel.

In one aspect, a variable volume vessel includes an expandable/contractable bellows along with one or more components and/or features that prevent over-travel of the bellows and/or that prevent binding of the bellow relative to an outer housing of the vessel.

Disclosed is a variable volume hydrogen container or hydrogen compressor including a variable vessel configured to expand due to hydrogen filling and to compress or discharge the hydrogen while contracting, a pressure vessel configured to receive the variable vessel, at least one of opposite ends of the pressure vessel being open, a vessel wire wound around the pressure vessel in a radial direction, a vessel cap configured to seal the at least one open end of the pressure vessel, a vessel frame configured to support a vessel assembly constituted by the vessel cap and the pressure vessel, a frame wire wound around the circumference of the vessel frame, an embrittlement blocking member disposed so as to overlap the vessel cap, the embrittlement blocking member being configured to block hydrogen from penetrating into the vessel cap, and a transmitted hydrogen discharge hole configured to discharge hydrogen to the outside.

Disclosed is a variable volume hydrogen container or hydrogen compressor including a variable vessel configured to expand due to hydrogen filling and to compress or discharge the hydrogen while contracting, a pressure vessel configured to receive the variable vessel, at least one of opposite ends of the pressure vessel being open, a vessel wire wound around the pressure vessel in a radial direction, a vessel cap configured to seal the at least one open end of the pressure vessel, a vessel frame configured to support a vessel assembly constituted by the vessel cap and the pressure vessel, a frame wire wound around the circumference of the vessel frame, an embrittlement blocking member disposed so as to overlap the vessel cap, the embrittlement blocking member being configured to block hydrogen from penetrating into the vessel cap, and a transmitted hydrogen discharge hole configured to discharge hydrogen to the outside.