METHOD FOR PRODUCING A PRESSURE ACCUMULATOR, AND PRESSURE ACCUMULATOR

Abstract

The invention relates to a method for producing a pressure accumulator (1), in particular for storing hydrogen in motor vehicles. First, a pressure accumulator liner (3) which has at least one pole cap (2, 2) is produced preferably by means of a plastic blow molding method, and the outside of the liner (3) is then provided, preferably braided, with a multi-ply reinforcing layer (9), which has reinforcing fibers (8). According to the invention, a fiber supply cap (10, 10) is applied on the pole cap (2, 2) prior to applying the reinforcing fibers (8), the outer surface of the fiber supply cap being spaced from the pole region (21, 21) of the pole cap (2, 2). The reinforcing fibers (8) are applied onto the body of the liner (3) and in the pole region (21, 21) so as to correspond to the outer surface of the fiber supply cap (10, 10) while the reinforcing layer (9) is applied such that the inner reinforcing layer (9) plies which are formed by the reinforcing fibers (8) are provided with a fiber supply (22) in the pole region (21, 21) on the basis of the distance between the outer surface of the fiber supply cap (10, 10) and the pole region (21, 21) of the pole cap (2, 2). The invention also relates to a pressure accumulator (1) produced in a corresponding manner.

Claims

1. A method for producing a pressure accumulator, in particular for storing hydrogen in motor vehicles, in which first, preferably by means of a plastic blow-molding process, a liner of the pressure accumulator is produced, which has at least one pole cap, and then the outside of the liner is provided with a multilayered reinforcing layer preferably produced by means of braiding, wherein before the reinforcing fibers are applied, a fiber supply cap is applied to the pole cap whose outer surface is spaced apart from the pole region of the pole cap; during the application of the reinforcing layer, the reinforcing fibers are placed onto the body of the liner and in the pole region, are correspondingly placed onto the outer surface of the fiber supply cap so that because of the distance between the outer surface of the fiber supply cap and the pole region of the pole cap, the inner plies of the reinforcing layer composed of the reinforcing fibers are provided with a fiber supply in the pole region, and wherein the fiber supply cap and the pole cap together form a cavity during the application of the reinforcing layer.

2. (canceled)

3. The method according to claim 1, wherein during the application of the reinforcing layer, the fiber supply cap is immobilized by an immobilizing device, which ensures the spacing of the fiber supply cap from the pole region during this process step.

4. The method according claim 1, wherein after the application of the reinforcing layer, the liner is inserted into a tool surrounding the reinforcing layer and is acted on with an internal positive pressure so that due to the action of the pressure, the pressure accumulator rests against the inner surface of the tool and the immobilizing device is released after the application of the reinforcing layer and because of the internal positive pressure in the liner, the fiber supply cap is slid into the pole region and the fiber supply is thus uncovered.

5. The method according to claim 4, wherein after this, the reinforcing layer is impregnated with a resin, preferably an epoxy resin, which after it hardens, freezes the reinforcing layer in the expanded state caused by the internal positive pressure.

6. The method according to claim 5, wherein the fiber supply cap in this case adapts to the outer contour of the pole cap in at least some areas.

7. The method according to claim 1, wherein the individual plies of the reinforcing layer are applied in such a way that the reversal points produced on the fiber supply cap at the transition between the individual plies are shifted axially toward the liner with increasing layer thickness.

8. (canceled)

9. (canceled)

10. (canceled)

11. A pressure accumulator, in particular for storing hydrogen in motor vehicles, having a preferably plastic-based liner, which has at least one pole cap, and a preferably braided multilayered reinforcing layer containing reinforcing fibers applied to the outside of the liner, wherein between pole cap and the reinforcing layer, a fiber supply cap is provided, which during the application of the reinforcing fibers onto the liner, ensures a fiber supply for the inner plies of the reinforcing layer, wherein in the completely manufactured state of the pressure accumulator, the shape of the fiber supply caps is adapted to the outer contour of the pole caps, and, wherein at least in some regions, preferably in the outer region, the fiber supply cap has an elastic deformability, which enables the adaptation to the outer contour of the pole cap.

12. A pressure accumulator, in particular for storing hydrogen in motor vehicles having a preferably plastic-based liner, which has at least one pole cap, and a preferably braided multilayered reinforcing layer containing reinforcing fibers applied to the outside of the liner, wherein between pole cap and the reinforcing layer, a fiber supply cap is provided, which during the application of the reinforcing fibers onto the liner, ensures a fiber supply for the inner plies of the reinforcing layer, wherein in the completely manufactured state of the pressure accumulator, the shape of the fiber supply caps is adapted to the outer contour of the pole caps, and, wherein the fiber supply cap has a circumferential material weakening, which functions as a hinge joint for the outer region of the fiber supply cap during the adaptation of the fiber supply cap to the outer contour of the pole cap.

13. (canceled)

14. The pressure accumulator according to claim 11, wherein in its outer region, the fiber supply cap has material reliefs extending toward the outer edge, which serve to facilitate adaptation to the outer contour of the pole cap in this region.

15. The pressure accumulator according to claim 11, wherein in the inner region close to the axis, the fiber supply cap has at least one connecting device for connecting the fiber supply cap to an immobilizing device, which serves to immobilize the fiber supply cap during the application of the reinforcing layer.

16. The pressure accumulator according to claim 11, wherein the reinforcing layer is impregnated with a resin, preferably an epoxy resin.

17. (canceled)

18. (canceled)

19. The method according to claim 3, wherein after the application of the reinforcing layer, the liner is inserted into a tool surrounding the reinforcing layer and is acted on with an internal positive pressure so that due to the action of the pressure, the pressure accumulator rests against the inner surface of the tool and the immobilizing device is released after the application of the reinforcing layer and because of the internal positive pressure in the liner, the fiber supply cap is slid into the pole region and the fiber supply is thus uncovered.

20. (canceled)

Description

[0015] The invention will be described below in conjunction with the drawings, which show only a single exemplary embodiment. In the drawings:

[0016] FIGS. 1a & 1b: schematically depict a respective side view and three-dimensional view of a pressure accumulator according to the invention during the manufacturing process;

[0017] FIGS. 2a & 2b: schematically depict the pressure accumulator shown in FIGS. 1a & 1b in the completely manufactured state,

[0018] FIG. 3: is a schematic, cross-sectional depiction of a detail of the pressure accumulator shown in FIGS. 1a-2b during the manufacturing process, and

[0019] FIGS. 4a-4d: schematically depict the fiber supply cap shown in FIG. 3 in different individual views.

[0020] FIGS. a, 1b, 2a, and 2b show a pressure accumulator 1 for storing hydrogen in a motor vehicle. The pressure accumulator 1 has a liner 3 made of plastic, with two pole caps 2, 2 and a cylindrical middle section 4, The two pole caps 2, 2 are formed onto this middle section 4. For filling and dispensing hydrogen, the pole cap 2 of the pressure accumulator 1 also has a fitting 5also referred to as a bosswith an opening 6. The pole cap 2 provided at the opposite end of the pressure accumulator 1 also has a so-called blind boss 7, which is only used for mounting the pressure accumulator 1 in the vehicle. A braided multilayered reinforcing layer 9 containing reinforcing fibers 8 is applied to the outside of the liner 3. In the exemplary embodiment, the reinforcing fibers 8 are embodied in the form of carbon fibers and in FIGS. 1a- 2b, only a few of them are individually indicated in order to improve visibility. Likewise, for the sake of better comprehension of the drawings, the reinforcing layer 9 is only schematically depicted in FIGS. 1a and 2a. FIGS. 1a and 2a clearly show that between the pole caps 2, 2 and the reinforcing layer 9, a respective fiber supply cap 10, 10 is provided, which, during the application of the reinforcing fibers 8 onto the liner 3, ensures a fiber supply 22 (see FIG. 3) for the inner plies of the reinforcing layer 9. FIG. 3 shows that during the application of the reinforcing layer 9, the fiber supply cap 10 and the pole cap 2 together form a cavity 11 and the fiber supply cap 10 is immobilized in a corresponding position by an immobilizing device 12. The fiber supply cap 10 and the pole cap 2 are positioned in an analogous fashion relative to each other. The fiber supply caps 10, 10 are each embodied as thin-walled, with an-average wall thickness of less than 5 mm and are made of plastic. In particular, FIGS. 2a and 2b show that in the complete, finished state of the pressure accumulator 1, the shape of the fiber supply caps 10, 10 is adapted to the outer contour of the pole caps 2, 2, To this end, the fiber supply caps 10, 10 are elastically deformable in the outer region 13, which enables adaptation to the outer contour of the pole caps 2, 2. This is particularly evident from a comparison of FIGS. 1a and 2a.

[0021] FIGS. 4a through 4d show different views of the fiber supply cap 10 shown as an individual part in FIG. 3. FIG. 4a shows a plan view from above, FIG. 4b shows the section A-A indicated in FIG. 4a, and FIGS. 4c and 4d show a three-dimensional, oblique view from above and below. The fiber supply cap 10 has a circumferential material relief 14, which, because it is weaker, functions as a hinge joint for the outer region 13 of the fiber supply cap 10 during the adaptation of this cap 10 to the outer contour of the pole cap 2. In an exemplary embodiment, the material relief 14 is composed of a plurality of circumferential slits 5. The circumferential slits 15 are distributed uniformly over the circumference. They pass all the way through the material of the fiber supply cap 10. As described above, the outer region 13 is elastic so that it can take on the corresponding contour of the pole cap 2 in this region. In its inner region 16 close to the axis, by contrast, the fiber supply cap 10 is rigid so that it can be rigidly connected to the immobilizing device 12. The geometry of the rigid inner region 16 of the fiber supply cap 10 is adapted to the contour of the pole cap 2 close to the axiswhich in the exemplary embodiment is composed of the contour of the boss 5. In its outer region 13, the fiber supply cap 10 also has material reliefs 17 extending toward the outer edge which serve to facilitate the adaptation to the outer contour of the pole cap 2 in this region 13. In an exemplary embodiment, these material reliefs 17 are each embodied in the form of a longitudinal slit. The longitudinal slits 17 are distributed uniformly around the circumference. As the fiber supply cap 10 adapts to the geometry of the pole cap 2, the longitudinal slits 17 are expanded (see FIGS. 2a & 2b). The longitudinal slits 17 also pass all the way through the material of the fiber supply cap 10. In its inner region 16 close to the axis, the fiber supply cap 10 also has a plurality of affixing openings 19, which together form a connecting device 20 for connecting the fiber supply cap 10 to the immobilizing device 12.

[0022] The method according to the invention for manufacturing the pressure accumulator 1 will be explained below in conjunction with FIG. 3. First, a plastic blow molding process is used to produce the liner 3 of the pressure accumulator 1, which is composed of a cylindrical middle section 4 with pole caps 2, 2 at the ends. The pole caps 2, 2 also include a boss 5 and a blind boss 7, which are preferably each composed of metal and are installed after the blow molding process. Then the multilayered reinforcing layer 9 with the reinforcing fibers 8 is braided into the outside of the liner 3 (for the sake of simplicity of illustration, FIG. 3 shows only the innermost plies of the reinforcing layer 9). Before the reinforcing fibers 8 are applied, a fiber supply cap 10, 10 is applied to both of the pole caps 2, 2, whose outer surface is spaced apart from the pole region 21, 21 of the corresponding pole cap 2, 2. During the application of the reinforcing layer 9, the reinforcing fibers 8 are applied to the body of the liner 3 and in the pole regions 21, 21, are correspondingly applied to the outer surface of the fiber supply caps 2, 2. Because of the distance between the outer surface of the fiber supply caps 10, 10 and the pole region 21, 21 of the pole caps 2, 2, the inner plies of the reinforcing layer 9 composed of the reinforcing fibers 8 are provided with a fiber supply 22 in the pole regions 21, 21.

[0023] FIG. 3 shows that during the application of the reinforcing layer 9, the fiber supply cap 10 and the pole cap 2 together with the boss 5 form a cavity 11. During the application of the reinforcing layer 9, the fiber supply cap 10 is immobilized by an immobilizing device 12, which ensures the spacing of the fiber supply cap 10 from the pole region 21 during this process step.

[0024] After the entire reinforcing layer 9 has been applied, the pressure accumulator 1 is inserted into an infiltration or injection tool, not shown, which completely encompasses the reinforcing layer 9 and which is adapted to the outer contour of the reinforcing layer 9, the immobilizing device 12 is detached, and the liner 3 is acted on with an internal positive pressure. In this case, the reinforcing layer 9 rests against the inner surface of the tool due to the action of the pressure. Because of the tensile stress of the applied reinforcing fibers 8, the fiber supply cap 10 shifts relative to the pole region 21 in the direction of the arrow x, thus uncovering the fiber supply 22.

[0025] When the fiber supply 22 is uncovered, the fiber supply caps 10, 10 adapt to the outer contour of the pole caps 2, 2which is partially composed of the boss 5 and blind boss 7, respectively (also see FIGS. 2a & 2b). To this endas explained above in connection with FIGS. 4a-4ethe outer region 13 of the fiber supply caps 10, 10 is elastic. In the exemplary embodiment, the transition from the rigid inner region 16 to the elastic outer region 13 of the fiber supply cap 10 corresponds essentially to the transition from the boss 5 to the blow molded part of the liner 3 with reference to the outer surface of the pole cap 2. In other words, the rigid inner region 16 of the fiber supply cap comes to rest against the surface of the boss 5, whereas the outer region 13, through an elastic deformation at the circumferential material relief 14, adapts to the adjacent surface contour of the blow mold part of the liner 3. It is also clear from FIG. 3 that before the fiber supply 22 is uncovered, the individual plies of the reinforcing layer 9 have been applied in such a way that the reversal points 23 produced on the fiber supply cap 10 at the transition between the individual plies are shifted axially toward the liner 3 with increasing layer thickness. The fiber supply cap 10 itself ensures a predetermined distance X from the pole cap 2, which largely determines the size of the fiber supply 22. By means of the fiber supply caps 10, 10, it is possible to exactly maintain and position the fiber lengths in all of the plies.

[0026] After the fiber supply caps 10, 10 have come to rest against the pole caps 2, 2, the reinforcing layer 9 in the infiltration or injection tool is impregnated with a resin (likewise not shown) in order to fill up the open spaces between the individual reinforcing fibers 8 and thus to further increase the strength of the reinforcing layer 9. Because of the internal positive pressure in the liner 3, the reinforcing layer 9 is radially compressed and as a result, has a reduced wall thickness. At the same time, this radial compression reduces the overall volume of the open spaces between the fibers 8 that must be filled by the resin. Through the hardening of the resin with the internal positive pressure in the liner 3, the shape of the compressed reinforcing layer 9 is largely retained in the unloaded pressure accumulator 1 after production is complete; it is frozen in, so to speak. On the one hand, this achieves a savings in weight and material since less resin material is required, and on the other hand, this simultaneously ensures a greater usable storage volume with predetermined outer dimensions of the pressure accumulator 1.