Fibre-reinforced pressure vessel

1 . A fiber-reinforced pressure vessel comprising:

an inner vessel made of a thermoplastic material for receiving a filling medium, the inner vessel having an outer face and a fiber composite layer arranged around the outer face for providing pressure resistance of the pressure vessel;

at least one valve connection connected to the inner vessel and the fiber composite layer; and

a thermoplastic band welded at least on a portion of the outer face of the inner vessel,

wherein the thermoplastic band comprises a fiber reinforcement comprising a carbon fiber-containing fiber reinforcement, the thermoplastic band having a matrix material identical with the inner vessel,

wherein the fiber composite layer is a layer with several plies of fiber composite material embedded in a thermosetting matrix, and

wherein the thermoplastic band has a thermal expansion coefficient lower than that of the inner vessel and is configured to keep any gap which may be created by thermal shrinkage between the fiber composite layer and the inner vessel smaller than would be the case without the presence of the thermoplastic band, and

wherein the thermoplastic band and at least an innermost ply of the several plies of the fiber composite layer facing the inner vessel cross each other and are intertwined.

2 . The pressure vessel according to claim 1 , wherein the thermoplastic band is additionally applied on a central portion and/or on a pole cap.

3 . The pressure vessel according to claim 1 , wherein the fiber composite layer consists of a thermosetting material.

4 . A method of manufacturing a fiber-reinforced pressure vessel comprising:

providing an inner vessel for receiving a filling medium made of a thermoplastic material, having an outer face, with at least one valve connection;

welding a thermoplastic band at least on a portion of the outer face of the inner vessel, wherein the thermoplastic band comprises a fiber reinforcement comprising a carbon fiber containing fiber reinforcement, the thermoplastic band having a matrix material identical with the inner vessel, wherein a fiber composite layer is a layer with several plies of fiber composite material embedded in a thermosetting matrix, and the thermoplastic band has a thermal expansion coefficient lower than that of the inner vessel and is configured to keep any gap which may be created by thermal shrinkage between the fiber composite layer and the inner vessel smaller than would be the case without the presence of the thermoplastic band, and wherein the thermoplastic band and at least an innermost ply of the several plies of the fiber composite layer facing the inner vessel cross each other and are intertwined; and

finishing the pressure vessel by applying a fiber composite layer on the outer face of the inner vessel provided with the thermoplastic band for providing pressure resistance of the pressure vessel.

5 . The method according to claim 4 , wherein applying the thermoplastic band comprises:

locally melting the thermoplastic material of the inner vessel to create a melting zone, by means of a laser beam directed at the inner vessel;

pressing the thermoplastic band, by means of a pressure roller, on the melting zone to create a welding connection between the inner vessel and the thermoplastic band, the thermoplastic band being fed to the pressure roller via a distance roller and the pressure and distance rollers tracking the laser beam over the outer face of the inner vessel.

6 . The method according to claim 5 , the local melting of the thermoplastic material of the inner vessel to create a melting zone being achieved by means of a laser beam directed at the inner vessel, the local melting and the laser beam being performed such or controlled such, respectively, that in addition to the material of the inner vessel, the thermoplastic band is also melted at least within the melting zone.