HIGH-PRESSURE CONTAINER

Description

Field of the invention

[0001] The present invention relates to a high-pressure container, in particular for storing a fuel for a motor vehicle. State of the art

[0002] It is known that high-pressure containers, for example for storing hydrogen as a fuel for motor vehicles, can be constructed from an inner layer, the so-called "liner", and a winding of fiber material around the liner.

[0003] Blow molding and thermoforming technologies are commonly used to manufacture containers. Production involves the forming of tubular or sheet-shaped semi-finished products. These are then brought into their final shape using negative and / or positive pressure. For example, two half-shells can be produced that are joined together to form a container.

[0004] For the application of gas-tight liners for Type IV vessels used for pressurized gas storage, there are two common production methods: blow molding of entire liners, and manufacturing vessel segments using injection molding and extrusion processes, followed by subsequent joining of these components.

[0005] The materials used here are mostly based on HDPE (high density polyethylene) or polyamides.

[0006] An important distinguishing feature for liner materials is their low-temperature mechanical properties and emission properties. Monolayer materials such as polyamide have good gas barrier properties, but not optimal low-temperature properties. HDPE, on the other hand, does not have a suitable barrier effect but does have very good low-temperature properties.

[0007] For this reason, polyamide is currently the primary material used, especially for hydrogen applications. However, this places limitations on component size, especially for blow molding technology. Furthermore, the available suitable grades are expensive due to their complex additives and problematic for use at low temperatures.

[0008] High-pressure gas vessels are subject to significant temperature fluctuations during operation (filling, storage, and emptying). This places high demands on the materials, especially on the liner.

[0009] In connection with the lightweight construction and the use of composite materials, the challenge arises in this context of connecting the different materials at the joint in a gas-tight manner.

[0010] From US 2019 / 170300 A1, a pressure vessel is known comprising a polymeric impermeable lining and a reinforcement layer of a composite material formed externally around the impermeable lining; at least one projection connected to the impermeable lining and the reinforcement layer to provide an opening of the pressure vessel, wherein the impermeable lining is connected to the projection by a co-molded annular polymer-metal bonding zone.

[0011] JP H10 332085 A and JP H10 332083 A each disclose a pressure-resistant container comprising a gas-tight inner shell, a pressure-resistant outer shell covering the inner shell, and a mouthpiece attached to at least one pole of the container comprising both shells, wherein the pole shoulder of the inner shell has a cylindrical neck projecting outwardly along the central axis of the inner shell; and the end of the projecting cylindrical neck is extended outwardly at right angles to the cylindrical neck to form an extension portion, the end of the extension portion being bent toward the shoulder of the inner shell to enclose the inner lower end of the mouthpiece.

[0012] Document US 2008 / 251520 A1 teaches a pressure vessel comprising a main body having a reinforcing portion having a tubular configuration and a liner portion made of resin and covering an inner peripheral surface of the reinforcing portion; an orifice ring formed integrally with the main body for communicating an inside and an outside of the main body; and a valve fitted into the orifice ring on an inner peripheral side thereof, the orifice ring having a cylindrical boss portion and a flange portion projecting outwardly from an outer peripheral surface of the boss portion.and the liner portion is formed integrally with the orifice ring and includes a flange seal portion covering a bottom surface of the flange portion and a hub seal portion continuously formed with the flange seal portion to cover at least a portion of an inner peripheral surface of the hub portion in its axial direction, wherein the hub seal portion includes a hub-side collar portion projecting outward, and a seal member composed of an elastic body is disposed in a space between an inner peripheral surface of the hub seal portion and an outer peripheral surface of the valve.; Summary of the invention

[0013] It is an object of the invention to improve a high-pressure vessel in this respect and, in particular, to provide a high-pressure vessel which meets the requirements for tightness and permeation for a high-pressure vessel even in a transition area to a boss part and can be produced easily and inexpensively.

[0014] The problem is solved by a high-pressure container having the features according to claim 1.

[0015] The high-pressure vessel comprises a cylinder as a central part, wherein the cylinder consists of a multi-layer composite plastic which comprises a barrier layer, wherein the high-pressure vessel further comprises at least one half-shell at an axial end of the cylinder, wherein the half-shell consists of a multi-layer composite plastic which comprises a barrier layer, wherein the half-shell further comprises a substantially rotationally symmetrical insert, namely a boss part, wherein the insert has a base part at the end of the insert facing the interior of the container, which base part has a larger diameter than a central part of the insert, wherein the base part essentially forms a hollow cone or hollow cylinder and at least one first groove or depression filled with the multi-layer composite plastic of the half-shell runs at least partially around a vertical inner circumference of the base part.

[0016] According to the invention, a multilayer composite is used as the material for the liner, both in the central section formed by the cylinder and in at least one, preferably both, axial end regions of the container. Such multilayer plastics can be easily formed into a half-shell by blow molding, deep drawing, or vacuum forming. The cylinder in the central section can also be blow-molded or extruded, for example. According to the invention, a boss part is used that has a base section with a larger diameter than an adjacent central section of the boss part.

[0017] The foot part thus forms an undercut in relation to a multi-layer plastic of the liner introduced from the side of the foot part or the center of the container.

[0018] The base part is hollow inside, in the area of ​​its longitudinal central axis, and therefore essentially forms a hollow cone or a hollow cylinder.

[0019] On an inner circumference of this hollow cone or hollow cylinder of the base part, a first groove or recess runs at least partially, for example, in individual sectors, around the inner circumference, preferably also around the entire inner circumference of the hollow cylinder or hollow cone. This groove or recess is filled with the multilayer composite plastic of the half-shell. A "recess" can be designed similarly to a groove and in any case has at least one edge that acts as an undercut for the plastic behind it, so that the multilayer plastic is held in a form-fitting manner behind the edge in the area of ​​the inner circumference.

[0020] The multi-layer plastic of the liner, which features a barrier layer, increases the tightness in the transition area between the plastic liner and the boss part. The plastic in the first groove or recess located on the vertical inner circumference is well protected against detachment during operation of the high-pressure vessel, ensuring the vessel's excellent sealing properties are particularly durable.

[0021] The high-pressure vessel thus exhibits good permeability properties even in the transition area to the boss part. The production of the half-shell with the embedded boss part and the entire high-pressure vessel is nevertheless possible cost-effectively, since, as will be described in more detail later, the plastic can be inserted using blow molding or vacuum forming despite the undercut at the base of the boss part.

[0022] According to the invention, the base part has at least one second groove filled with the multi-layer composite plastic of the half-shell. The second groove extends at least partially around the base of the base part near the inner circumference of the base part, facing the interior of the container. This groove also primarily serves to increase the tightness between the liner and the boss part.

[0023] According to the invention, the base part has at least a fourth groove filled with the multi-layer composite plastic of the half-shell. The fourth groove extends at least partially around the base of the base part near the outer periphery of the base part, facing the interior of the container. This groove also prevents the plastic from detaching from the boss part.

[0024] The multi-layer composite plastic of the half-shell is preferably arranged axially on both sides of the foot part. The usually metallic boss part is thus embedded in the plastic containing the barrier layer.

[0025] Preferably, the base part has at least a third groove filled with the multi-layer composite plastic of the half-shell, with the third groove extending at least partially around the cover surface of the base part facing the outside of the container. In addition to increasing the tightness, this third groove also prevents the plastic from detaching from the boss part on the cover surface of the base part.

[0026] The first groove and / or the second groove and / or the third groove and / or the fourth groove may have a trapezoidal shape which increases towards the bottom of the groove so that the form fit of the plastic in the groove is improved.

[0027] In each of the grooves, preferably especially in the first and / or second groove, an additional sealing element can be arranged at the bottom of the groove.

[0028] Preferably, a sleeve is arranged radially within the first groove, within the inner circumference of the base part, whereby the multi-layer composite plastic of the half-shell is pressed by the sleeve against the inner circumference of the base part and into the first groove. The plastic thus remains reliably in the first groove, further increasing the sealing effect.

[0029] The multilayer composite plastic of the cylinder preferably merges into the multilayer composite plastic of the half-shell. The barrier layer preferably runs as continuously as possible at the transition between the cylinder and the half-shell.

[0030] The multi-layer composite plastic of the half-shell, and preferably also the multi-layer composite plastic of the cylinder, preferably comprises at least one layer of HDPE and a barrier layer, in particular EVOH, preferably also a regranulate, i.e. a regrind layer, and / or a second HDPE layer and / or at least one adhesion promoter layer.

[0031] Preferably, the high-pressure vessel comprises two half-shells at the axial ends of the cylinder, wherein preferably both half-shells are designed as previously described for the first half-shell.

[0032] The cylinder and the two half-shells are preferably wrapped with a fiber material, preferably with a composite material comprising carbon fibers and / or glass fibers and / or epoxy resin.

[0033] The production of a high-pressure container according to the invention can preferably be carried out with a tool, with a first tool half forming a die, and the steps include: a preheated first plastic sheet is placed on the first tool half, the first plastic sheet is sucked or pressed onto the first tool half by means of vacuum or pressure, as a result of which the plastic of the first plastic sheet is arranged in regions behind an undercut of an insert, namely the boss part, laterally spaced from the insert, or the insert is positioned, after the first plastic sheet has been sucked or pressed onto the first tool half, in such a way that the plastic of the first plastic sheet is arranged in regions behind an undercut of the insert, laterally spaced from the insert, then the plastic of the first plastic sheet is pressed or sucked onto the insert behind the undercut, laterally spaced from the insert, by means of a slider or vacuum or pressure,so that a space behind the undercut of the insert is filled with the plastic.

[0034] Preferably, the boss part is inserted into the tool as an insert and enclosed in a blow molding or deep-drawing process with the plastic sheet, in particular a permeation-tight multi-layer composite, so that the plastic also reaches areas behind an undercut. For this purpose, a plastic sheet is first sucked or pressed onto the first tool half using vacuum or pressure. The insert can already be positioned such that, by sucking or pressing the plastic onto the first tool half, the plastic of the first plastic sheet is arranged in some areas behind an undercut of the insert, laterally spaced from the insert.

[0035] Alternatively, the insert can be positioned only after the plastic has been sucked or pressed onto the first tool half in such a way that the plastic of the first plastic plate is arranged behind the undercut at a laterally spaced distance from the insert, for example by moving the insert or by only now inserting the insert into the first tool half.

[0036] Then, by means of a slider or a vacuum or a pressure, the plastic of the first plastic plate is pressed or sucked from the side of the insert towards the insert, so that a space behind the undercut of the insert is filled with the plastic previously located on the side and a positive fit is created.

[0037] This allows the plastic to penetrate into the areas behind the insert, despite the simple production process using blow molding or vacuum forming, resulting in an improved sealing effect of the plastic, especially in multi-layer composites, on the insert, especially on the metal boss part. Slide valves and / or a vacuum or compressed air are used to achieve the encapsulation within the plastic.

[0038] "Laterally spaced" essentially means spaced from a longitudinal center axis of the insert, which can preferably also coincide with the longitudinal center axis of the pressure vessel. The plastic can initially run essentially parallel to the longitudinal center axis of the insert and preferably also to the surrounding vessel wall. The plastic is then sucked, blown, or pushed essentially perpendicular to the longitudinal center axis of the insert, in particular radially inward on all sides, toward the insert.

[0039] The fact that the plastic is sucked or pushed towards the insert part after the positioning of the insert part, so that the plastic is arranged laterally spaced from the insert part in some areas, can also take place in a continuous process, so that the insert part is moved and positioned further and in the process new plastic is sucked or pushed in, so that the positioning of the insert part and the sucking or pushing of the plastic behind the undercut take place almost simultaneously.

[0040] The resulting half-shell can be joined to a second half-shell or an extruded or blow-molded multi-layer cylinder in a subsequent process step. This forms the core and thus the basis for a further winding process, in which the container can obtain its mechanical strength through a composite material made of carbon and / or glass and epoxy resin.

[0041] Preferably, the tool comprises a second tool half that forms a punch, wherein the second tool half is moved onto the first tool half to form the inner contour of the half-shell. The second tool half can also form the shape of the first plastic plate inside the half-shell. Alternatively, the second tool half can also be equipped with a second plastic plate that forms the inner contour of the half-shell.

[0042] Preferably, after the first plastic plate has been sucked or pressed onto the first tool half, the insert is lifted relative to the first tool half in order to position the insert such that plastic of the first plastic plate is arranged behind the undercut at a laterally spaced distance from the insert. The lifting can be carried out with the aid of a movable holder for the insert. The insert can be arranged on the outside of the container on the first plastic plate, and the lifting can thus take place along the longitudinal center axis of the insert and preferably also along the longitudinal center axis of the high-pressure container, in particular in the direction of the later center of the container.

[0043] Preferably, after the space behind the undercut of the insert has been filled with plastic, the insert is lowered again relative to the first mold half. Particularly preferably, the lowering occurs simultaneously with the movement of the second mold half onto the first mold half.

[0044] According to another embodiment, the insert is placed on the first plastic plate only after the first plastic plate has been suction- or pressed onto the first mold half, in order to position the insert such that the plastic of the first plastic plate is arranged behind the undercut, laterally spaced from the insert. The insert can thus be arranged on the inside of the container on the first plastic plate. A second plastic plate can, in turn, be arranged on the inside of the container on the insert.

[0045] The plastic of the first plastic plate can be cut off axially behind the space filled with plastic behind the undercut, so that there is no more plastic behind the undercut, in particular on the outside of the container of the undercut.

[0046] Preferably, a preheated second plastic plate is placed on the second tool half, then the second plastic plate is sucked or pressed onto the second tool half by means of negative pressure or pressure, and the second tool half with the second plastic plate is moved onto the first tool half in order to form the inner contour of the half-shell.

[0047] The first plastic sheet is preferably a multilayer composite, wherein the multilayer composite preferably comprises a layer of HDPE (high-density polyethylene) and a barrier layer, in particular EVOH (ethylene-vinyl alcohol copolymer). Particularly preferably, the multilayer composite also comprises a regrind material or regranulate and / or one or more adhesion promoter layers. HDPE preferably forms the outermost layer of the multilayer composite and can also additionally form the innermost layer.

[0048] A method for producing a high-pressure container preferably comprises producing a half-shell by a method as described above, wherein the half-shell is connected to another half-shell - which may, for example, also comprise an insert and which may be produced in the same manner as described above - or to at least one - preferably extruded or blow-molded - cylinder and an end cap to form a closed container.

[0049] The closed container is preferably wrapped with a fiber material, preferably with a composite material comprising carbon fibers and / or glass fibers and / or epoxy resin. Brief description of the drawings

[0050] The invention is described below by way of example with reference to the drawings. Fig. 1 - Fig. 6 are sectional views showing the steps of a method for producing a half-shell for a high-pressure vessel according to the invention in a first embodiment. Fig. 7 is a detailed view of the Fig. 3 in the area around the undercut of the insert 1. Fig. 8 is a detailed view of the Fig. 4in the area around the undercut of the insert part 1. Fig. 9 - Fig. 14 are sectional views showing the steps of a method for producing a half-shell for a high-pressure vessel according to the invention in a second embodiment. Fig. 15 is a sectional view of a high-pressure vessel according to the invention. Fig. 16 is a sectional view of a half-shell of a high-pressure vessel according to the invention. Fig. 17 is a sectional view of another half-shell of a high-pressure vessel according to the invention. Fig. 18 is a sectional view of another half-shell of a high-pressure vessel according to the invention. Fig. 19 is a sectional view of detail A of the half-shell according to Fig. 18 . Detailed description of the invention

[0051] In the Fig. 1-6 a method for producing a half-shell for a high-pressure vessel according to the invention is shown.

[0052] A tool is used with a first tool half 2, which forms a die, and with a second tool half 5, which forms a punch.

[0053] The tool thus consists of two halves, with the insert being positioned on a movable holder 7 in the first half 2, preferably the lower half. The second half 5, preferably the upper half, acts as a punch to apply a compression at the end of the process. Additionally, the second half 5 can also be equipped with a second insert. With the aid of slides 4 provided in the tool and / or a vacuum, the plastic is brought to the locations required for the mold closure.

[0054] For this purpose, a preheated first plastic sheet 3 is placed on the first tool half 2 and the first plastic sheet 3 is sucked or pressed onto the first tool half 2 by means of vacuum or pressure. The insert 1, i.e. the boss part, is then positioned so that the plastic of the first plastic sheet 3 is arranged in regions behind an undercut, laterally spaced from the insert 1. Alternatively, the movement of the insert 1 can be omitted, so that the plastic is immediately applied to a correctly positioned insert 1, corresponding to Fig. 3 , is sucked.

[0055] Then, by means of a slider 4 or a vacuum or a pressure, the plastic of the first plastic plate 3 behind the undercut of the insert part 1 is pressed or sucked onto the insert part 1 at a laterally spaced distance, so that a space behind the undercut of the insert part 1 is filled with the plastic.

[0056] Finally, the second tool half 5 is moved onto the first tool half 2 to form the inner contour of the half shell.

[0057] The Fig. 1 to 6 Singlesheet method shows the following steps in detail: In the first step of the singlesheet method ( Fig. 1 ), one tool half, namely the first tool half 2, is loaded with the insert 1 – namely a boss part – and a preheated plastic plate 3. The insert 1 is in the starting position.

[0058] Optionally, the second mold half 5 can also be equipped with another insert at this point. The plastic plate 3 is sucked into the first mold half 2, which represents the outer component geometry, using a vacuum.

[0059] In order to fill the space behind the undercut of the insert 1 with plastic, which is necessary for the form fit, the insert 1 is positioned in the first tool half 2 on a movable holder 7. By lifting the component and, for example, the simultaneous use of vacuum and / or sliders 4, the space behind the undercut of the component is filled - Fig. 3 and Fig. 4 .

[0060] In the next step ( Fig. 5 ), the second mold half 5 is lowered onto the first mold half 2 with a defined clamping force, and the inner contour of the component is formed. During this process step, the insert 1 can be returned to its original position if necessary. This further compresses the plastic behind the undercuts and increases the form fit between the insert 1 and the plastic of the first plastic plate 3.

[0061] An alternative version of the manufacturing process is shown in the Fig. 9 to Fig. 14 , namely a twinsheet process for producing the half shell.

[0062] In the first step of the twinsheet process, both tool halves 2, 5 are each equipped with a preheated plastic plate 3, 6 ( Fig. 9 ). Optionally, the second mold half 5 can also be equipped with an insert at this point. The plastic plates 3, 6 are sucked into or onto the respective mold halves 2, 5 by means of a vacuum, which represent the outer or inner component geometry ( Fig. 10 ).

[0063] In the next step, the insert 1 to be enclosed is inserted into the first tool half 2 ( Fig. 11 ).

[0064] With the help of vacuum and / or sliders 4, the space behind the undercut of the insert 1 required for the form fit is filled with plastic ( Fig. 12). The excess material is cut off behind the undercut by cutting edges incorporated into the tool ( Fig. 13 ). These cutting edges can, as in Fig. 13 , also be included in sliders 4. Fig. 14 shows the finished component, with the excess plastic below the undercut and the slider 4 cut off.

[0065] A high-pressure vessel according to the invention is Fig. 15shown. The high-pressure vessel comprises a cylinder 10 as a central part, wherein the cylinder 10 consists of a multi-layer composite plastic 11 which comprises a barrier layer 12, wherein the high-pressure vessel further comprises at least one half-shell 13 at one axial end of the cylinder 10, wherein the half-shell 13 consists of a multi-layer composite plastic 11 which comprises a barrier layer 12, wherein the half-shell 13 further comprises a substantially rotationally symmetrical insert 1, namely a boss part, wherein the insert 1 comprises an undercut with respect to demolding in the direction of the longitudinal central axis of the insert 1, wherein the multi-layer composite plastic 11 of the half-shell 13 is arranged axially on both sides of the undercut of the insert 1.

[0066] The undercut is formed by a foot part 14 at the end of the insert part 1 facing the container interior, which has a larger diameter than a middle part of the insert part 1. The multi-layer composite plastic 11 is arranged axially on both sides of the foot part 14.

[0067] The foot part 14 has several grooves 15 which are filled with the multi-layer composite plastic 11 of the half-shell 13.

[0068] The insert part 1 essentially has the shape of a hollow cylinder. The base part 14 essentially has the shape of a hollow cone.

[0069] A groove 15 filled with the multi-layer composite plastic 11 of the half-shell 13 runs around an inner circumference of the foot part 14.

[0070] The multi-layer composite plastic 11 of the cylinder 10 merges into the multi-layer composite plastic 11 of the half-shell 13.

[0071] The multilayer composite plastic 11 of the half-shell 13 and the cylinder 10 comprises a layer of HDPE as the outermost layer and a barrier layer 12 of EVOH. The HDPE can be HDPE-S (black), followed by a regranulate layer, an adhesion promoter, the EVOH layer, optionally another adhesion promoter, and optionally another HDPE layer as the innermost layer.

[0072] The high-pressure vessel comprises two half-shells 13 at the axial ends of the cylinder 10, wherein both half-shells 13 are designed as previously described, i.e. have a boss part 1 that is embedded in the multi-layer composite plastic 11.

[0073] The cylinder 10 and the two half-shells 13 are wrapped with a fiber material 16, preferably with a composite material comprising carbon fibers and / or glass fibers and / or epoxy resin.

[0074] Overall, a high-pressure vessel is thus specified that can be used to store gases under high pressure. It is designed in a lightweight construction and features a multi-part, multi-layer plastic liner consisting of two dome caps 13 and a cylinder 10, which ensures gas tightness and contains a permeation barrier 12.

[0075] Boss parts 1, namely a "headstock" and a "tailstock", are integrated into the two dome caps 13.

[0076] The permeation properties are provided by a barrier layer 12 contained in the layer structure of the liner in both the dome caps 13 and the cylinder tube 10.

[0077] The high-pressure vessel gets its mechanical strength from a fiber-reinforced composite 16, which is applied to the plastic liner during the winding process and then cured.

[0078] Fig. 16shows a half-shell 13 of a high-pressure vessel according to the invention. The half-shell 13 consists of a multi-layer composite plastic 11 comprising a barrier layer 12, wherein the half-shell 13 further comprises a substantially rotationally symmetrical insert 1, namely a boss part. The insert 1 has a base part 14 at the end of the insert 1 facing the container interior, which has a larger diameter than a central part of the insert 1. The base part 14 essentially forms a hollow cone. A first groove 15 filled with the multi-layer composite plastic 11 of the half-shell 13 encircles the inner circumference of the base part 14.

[0079] The multi-layer composite plastic 11 of the half-shell 13 is arranged axially on both sides of the foot part 14.

[0080] The base part 14 has a second groove 17 which is filled with the multi-layer composite plastic 11 of the half-shell 13, wherein the second groove 17 runs near the inner circumference of the base part 14 on the bottom of the base part 14 facing the interior of the container.

[0081] The base part 14 has a third groove 18 which is filled with the multi-layer composite plastic 11 of the half-shell 13, wherein the third groove 18 runs around the cover surface of the base part 14 facing the outside of the container.

[0082] The base part 14 has a fourth groove 19 which is filled with the multi-layer composite plastic 11 of the half-shell 13, wherein the fourth groove 19 runs near the outer circumference of the base part 14 on the bottom of the base part 14 facing the interior of the container.

[0083] As in Fig. 17As shown, a sleeve 20 can be arranged radially inside the first groove 15, within the inner circumference of the foot part 14, wherein the multi-layer composite plastic 11 of the half-shell 13 is pressed by the sleeve 20 against the inner circumference of the foot part 14 and into the first groove 15.

[0084] As in the Fig. 18 and the detail section of detail A in Fig. 19 As can be seen, a sealing element can be arranged at the bottom of the grooves, in particular the first groove 15 and the second groove 17.

[0085] The primary sealing effect is achieved by pressing the plastic in the annular grooves 15 and 17 on the metal base or in the core hole of the foot part of the boss part 1. Two further grooves 18, 19 on the outside of the plate or plate surface serve primarily to ensure positive locking and to stabilize the plastic-metal connection.

[0086] Optionally, a sleeve 20 can be inserted into the core hole during the manufacturing process in order to increase the compression on the sealing plastic material in the first groove 15.

[0087] In a further option, one or both sealing grooves 15, 17 - as in Fig. 19 shown - provided with an additional sealing element to increase the sealing effect in this area. List of reference symbols

[0088] 1Insert, boss part 2First tool half 3First plastic plate 4Slider 5Second tool half 6Second plastic plate 7Holder 10Cylinder 11Multi-layer composite plastic 12Barrier layer 13Half shell 14Foot part 15First groove 16Fiber material 17second groove 18third groove 19fourth groove 20sleeve

Claims

1. High-pressure vessel comprising a cylinder (10) as middle part, wherein the cylinder (10) is composed of a multilayer composite plastic (11) comprising a barrier layer (12), wherein the high-pressure vessel also comprises at least one half-shell (13) at an axial end of the cylinder (10), wherein the half-shell (13) is composed of a multilayer composite plastic (11) comprising a barrier layer (12), wherein the half-shell (13) also comprises a substantially rotationally symmetrical insert part (1), namely a boss, wherein the insert part (1) has a foot part (14) at that end of the insert part (1) which faces the vessel interior, said foot part having a greater diameter than a middle part of the insert part (1), wherein the foot part (14) substantially forms a hollow cone or hollow cylinder and at least a first groove (15) or recess, filled with the multilayer composite plastic (11) of the half-shell (13), runs around at least in certain portions on a vertical inner circumference of the foot part (14), characterized in that the foot part (14) has at least a second groove (17) which is filled with the multilayer composite plastic (11) of the half-shell (13), wherein, in the vicinity of the vertical inner circumference of the foot part (14), the second groove (17) runs around at least in certain portions on the base of the foot part (14), said base facing the vessel interior, wherein the foot part (14) has at least a fourth groove (19) which is filled with the multilayer composite plastic (11) of the half-shell (13), wherein, in the vicinity of the outer circumference of the foot part (14), the fourth groove (19) runs around at least in certain portions on the base of the foot part (14), said base facing the vessel interior.

2. High-pressure vessel according to Claim 1, characterized in that the multilayer composite plastic (11) of the half-shell (13) is arranged axially on both sides of the foot part (14).

3. High-pressure vessel according to at least one of the preceding claims, characterized in that the foot part (14) has at least a third groove (18) which is filled with the multilayer composite plastic (11) of the half-shell (13), wherein the third groove (18) runs around at least in certain portions on the top surface of the foot part (14), said top surface facing the outer side of the vessel.

4. High-pressure vessel according to at least one of the preceding claims, characterized in that a sleeve (20) is arranged radially on the inside in relation to the first groove (15), on the inside in relation to the inner circumference of the foot part (14), wherein the multilayer composite plastic (11) of the half-shell (13) is pushed by the sleeve (20) against the inner circumference of the foot part (14) and into the first groove (15).

5. High-pressure vessel according to at least one of the preceding claims, characterized in that the multilayer composite plastic (11) of the cylinder (10) transitions into the multilayer composite plastic (11) of the half-shell (13).

6. High-pressure vessel according to at least one of the preceding claims, characterized in that the multilayer composite plastic (11) of the half-shell (13) comprises at least one layer composed of HDPE and a barrier layer (12), in particular EVOH, and preferably also comprises a regranulate and / or a second HDPE layer and / or at least one adhesion-promoter layer.

7. High-pressure vessel according to at least one of the preceding claims, characterized in that the high-pressure vessel comprises two half-shells (13) at the axial ends of the cylinder (10), wherein the two half-shells (13) are preferably configured as described in at least one of the preceding claims.

8. High-pressure vessel according to at least one of the preceding claims, characterized in that a fibre material (16), preferably a composite material comprising carbon fibres and / or glass fibres and / or epoxy resin, is wound around the cylinder (10) and the two half-shells (13).