A multilayer structure for storing hydrogen, including, from the inside, at least one sealing layer and at least one composite reinforcement layer, an innermost composite reinforcement layer being welded to an outermost adjacent sealing layer, the sealing layers being a composition predominantly of: at least one semi-crystalline polyamide thermoplastic polymer P1i, i=1 to n, n being the number of sealing layers, excluding an amide polyether block (PEBA), up to 50% by weight of impact modifier relative to the total weight of the composition, up to 1.5% by weight of plasticizer relative to the total weight of the composition, and at least one of the composite reinforcement layers of a fibrous material in the form of continuous fibers, which is impregnated with a composition predominantly of at least one semi-crystalline polyamide polymer P2j, j=1 to m, m being the number of reinforcement layers.

A compressed gas storage system that includes a pressure vessel. The pressure vessel includes a first vessel portion and a second vessel portion in fluid communication with the first vessel portion. The pressure vessel includes a third vessel portion in fluid communication with the second vessel portion. The compressed gas storage system includes a first valve positioned between the first vessel portion and the second vessel portion and a second valve positioned between the second vessel portion and the third vessel portion. The first valve allows and impedes fluid flow between the first and the second vessel portions. The second valve allows and impedes fluid flow between the second and the third vessel portions.

A hollow molded article having a joining site where two or more split objects are welded by plastic welding and comes into contact with pressurized hydrogen, wherein an average spherulite size in a portion which is 500 μm deep inside from a surface of the hollow molded article is 20 μm or less, and a tensile strength of a test piece containing the joining site of the hollow molded article is 80% or more based on a tensile strength of a test piece not containing the joining site of the hollow molded article.

A high-pressure vessel that includes a cylinder, at least one half-shell, and a substantially rotationally symmetrical insert member. The cylinder, forming a middle region of the high-pressure vessel, is composed of a multilayer composite plastic having a first barrier layer. The at least one half-shell is formed at an axial end of the cylinder, and is composed of a multilayer composite plastic having a second barrier layer. The substantially rotationally symmetrical insert member has a foot member at an end thereof which faces an interior of the high-pressure vessel. The foot member has a diameter that is greater than a diameter of a middle region of the insert member. The foot member is configured to substantially form a hollow cone or hollow cylinder and at least a first groove or recess filled with the multilayer composite plastic of the at least one half-shell, and which is configured to extend around at least in certain portions on an inner circumference of the foot member.

A high-pressure tank for storing a gas includes: a liner having a cylindrical opening; a reinforcing layer covering the liner; a mouthpiece including an external thread portion on an outer periphery thereof and externally fixed to the reinforcing layer covering the opening; a manifold including an inserted portion to be inserted into the opening so as to close the opening, an abutting surface configured to abut on an end face of the opening, and an internal thread portion on an inner periphery thereof to be screwed into the external thread portion of the mouthpiece; and a communicating path that allows the abutting surface of the manifold to communicate with an outside of the high-pressure tank.

A high-pressure tank includes a liner that includes a body that is cylindrical in shape and a pair of dome portions each of which is provided at a respective end of the body in an axial direction, and a reinforcing layer provided on an outer circumferential face of the liner. The reinforcing layer includes a pair of resin rings each of which is provided encircling a respective end portion of an outer circumferential face of the body, a hoop layer that covers part of the outer circumferential face of the body, between the resin rings, and a helical layer that covers the resin rings, the hoop layer, and the dome portions. The resin rings are configured to cover part of the body from boundary portions between the body and the dome portions, and increase in thickness from the boundary portions toward a middle of the body.

An internal casing for a pressurized fluid storage tank for a motor vehicle includes: a hollow body includes a layer made of a first polymer material; and a neck arranged on the hollow body and delimiting an opening of the hollow body, the neck receiving an interface part mounted on the neck in a sealed manner by a gasket arranged between the neck and the interface part. The neck is made of a composite material composed of a second polymer material loaded with reinforcing fibers, the composite material having a deformation resistance than that of the first polymer material. The neck is joined to the hollow body by molecular entanglement of polymer chains of the first polymer material and polymer chains of the second polymer material. Methods for manufacturing such an internal casing, and a storage tank including such an internal casing are disclosed.

An internal casing for a pressurized fluid storage tank for a motor vehicle includes: a hollow body includes a layer made of a first polymer material; and a neck arranged on the hollow body and delimiting an opening of the hollow body, the neck receiving an interface part mounted on the neck in a sealed manner by a gasket arranged between the neck and the interface part. The neck is made of a composite material composed of a second polymer material loaded with reinforcing fibers, the composite material having a deformation resistance than that of the first polymer material. The neck is joined to the hollow body by molecular entanglement of polymer chains of the first polymer material and polymer chains of the second polymer material. Methods for manufacturing such an internal casing, and a storage tank including such an internal casing are disclosed.

A high-pressure container includes a cylinder composed of plastic, at least one half-shell composed of plastic, a substantially rotationally symmetrical insert as a boss member, and a sleeve. The cylinder is to serve as a centre member, while the at least one half-shell is at an axial end of the cylinder. The insert as a boss member, the insert having a foot member at an end thereof facing the container interior. The foot member is embedded in the plastic of the half-shell to substantially form a hollow cone or hollow cylinder. The sleeve is pressed into the inner circumference of the foot member at least in a pressing portion of the sleeve. The plastic of the half-shell is arranged between the sleeve and an inner circumference of the foot member so that in a pressing portion, a thin plastic layer of the plastic of the half-shell is pressed between the sleeve and the inner circumference of the foot member.

A compressed gas storage system that includes a pressure vessel. The pressure vessel includes a first vessel portion and a second vessel portion in fluid communication with the first vessel portion. The pressure vessel includes a third vessel portion in fluid communication with the second vessel portion. The compressed gas storage system includes a first valve positioned between the first vessel portion and the second vessel portion and a second valve positioned between the second vessel portion and the third vessel portion. The first valve allows and impedes fluid flow between the first and the second vessel portions. The second valve allows and impedes fluid flow between the second and the third vessel portions.