High-pressure gas tank

Abstract

High-Pressure Gas Reservoir The invention relates to a reservoir (1) for pressurized gases, such as hydrogen, comprising a structure (2) and a flexible casing, wherein the casing comprises at least two cells, each cell extending along a first axis (X), and in that the structure (2) extends along the first axis (X) and has, perpendicular to the first axis (X), a ladder-like structural section, comprising an outer wall surrounding the outer periphery of said at least two cells and, for each pair of adjacent cells, an inner wall separating the cells of the pair and being integral, at both ends, with the outer wall. Abbreviated figure: Figure 1

Description

Title of the invention: High-pressure gas reservoir technical field

[0001] The invention relates to a reservoir for gases under high pressure, such as hydrogen. High pressure is understood to mean a pressure of up to 1000 bar. Previous technique

[0002] It is known to produce a high-pressure gas tank with a structure, typically made of composite material, ensuring resistance to structural mechanical stresses, lined with an internal flexible casing, ensuring sealing, supported against the structure.

[0003] For certain applications, particularly for applications embedded in motor vehicles, a substantially flat and planar tank shape is sought to facilitate integration. Such a shape is challenging because it entails structural stresses related to high pressure.

[0004] The present invention presents an ingenious paradigm that advantageously addresses this problem. Summary of the invention

[0005] The invention aims to provide a reservoir for pressurized gas, such as hydrogen, comprising a structure and a flexible envelope, wherein the envelope comprises at least two cells, one cell extending along a first axis and in that the structure extends along the first axis and presents, perpendicular to the first axis, a ladder structure section, comprising an external wall surrounding the external periphery of said at least two cells and for each pair of neighboring cells, an internal wall separating the cells of the pair, and being attached, at its two ends, to the external wall.

[0006] Specific features or embodiments, usable alone or in combination, are:

[0007] - a cell presents, perpendicular to the first axis, a cell section essentially constant along the first axis,

[0008] - each alveolus comprises a tube along the first axis, preferably made by extrusion, a first operculum disposed at one end of the tube and a second operculum disposed at a second end of the tube, substantially flat along a plane perpendicular to the first axis, preferably made by injection, assembled in a hermetic manner at the end, preferably by welding, even more preferably by hot air welding or by mirror welding,

[0009] - all the lids at the same end are made of material,

[0010] - said at least two alveoli are substantially identical and extend side by side, parallel to each other, in a layer, along a second axis substantially perpendicular to the first axis, so that the reservoir has a substantially flat extension.

[0011] - said at least two alveoli are substantially identical and extend side by side parallel to each other, in two layers, along the second axis,

[0012] - the tank further comprises at least one stiffener disposed between the two layers, preferably parallel to the first axis,

[0013] - the structure is made of composite material and comprises a woven fiber fabric, non-woven, braided or wound, impregnated in a hardening resin,

[0014] - the fiber fabric is made in one piece,

[0015] - the fiber fabric is woven with an irregular warp and weft distribution, in order to to adapt its strength to the distribution of constraints,

[0016] - the casing includes surface grooves to facilitate the insertion of the hardening resin between the envelope and the fiber canvas.

[0017] According to a second aspect of the invention, a method for manufacturing such a reservoir comprising the following operations: manufacturing, for each of said at least two cells, of a tube, preferably by extrusion, arranging the tubes side by side, threading the fiber fabric of the structure around the tubes, welding two caps, at each end of each tube, impregnating the fiber fabric with a hardenable resin. Brief description of the drawings

[0018] The invention will be better understood upon reading the following description, given solely by way of example, and with reference to the figures in the appendix in which:

[0019] [Fig-1] shows, in perspective view, a reservoir according to a first embodiment,

[0020] [Fig.2] shows, in perspective view, a reservoir according to a second mode of realization,

[0021] [Fig.3] shows, in perspective view, an assembly step of the tank of the [Fig.1],

[0022] [Fig.4] shows, in a cross-sectional view perpendicular to the first X axis, the reservoir of the [Fig.l],

[0023] [Fig.5] shows, in perspective view, an assembly step of the tank of the [Fig.2],

[0024] [Fig.6] shows, in a cross-sectional view perpendicular to the first X axis, the reservoir of the [Fig.2],

[0025] [Fig.7] shows, in perspective view, the structure of the reservoir of [Fig.1], before its assembly,

[0026] [Fig.8] shows, in perspective view, the structure of the tank of [Fig.1], after its assembly,

[0027] [Fig.9] shows, in a cut-off view perpendicular to the second axis Y, the reservoir of the [Fig.1],

[0028] [Fig. 10] shows, in a cut-off view perpendicular to the second Y axis, the reservoir of the [Fig.2],

[0029] [Fig. 11] shows, in a cross-sectional view perpendicular to the first X-axis or the second Y-axis, the detail of the assembly of a lid of a cell,

[0030] [Fig. 12] shows, in a cross-sectional view perpendicular to the second Y-axis, the detail of the attachment of the structure to a collector, according to a first embodiment,

[0031] [Fig. 13] shows, in a cross-sectional view perpendicular to the second Y-axis, the detail of the attachment of the structure to a collector, according to another embodiment,

[0032] [Fig. 14] shows, in a cross-sectional view perpendicular to the second Y-axis, the detail of the attachment of the structure to a collector, according to another embodiment,

[0033] [Fig. 15] shows, in a cross-sectional view perpendicular to the second Y-axis, the detail of the attachment of the structure to a collector, according to another embodiment,

[0034] [Fig. 16] shows, in detail, the connection of a socket to a conduit, according to a first embodiment,

[0035] [Fig. 17] shows, in detail, the connection of a socket to a conduit, according to another embodiment,

[0036] [Fig. 18] shows, in partial perspective view, a primary collector and enclosure assembly, according to a first embodiment,

[0037] [Fig. 19] shows, in partial perspective view, a second collector and casing assembly, according to a first embodiment,

[0038] [Fig.20] shows, in partial perspective view, a primary collector and enclosure assembly, according to a second embodiment,

[0039] [Fig.21] shows, in partial perspective view, a second collector assembly and envelope, according to a second embodiment. Description of the implementation methods

[0040] With reference to Figures 1 or 2, the invention relates to a reservoir 1 for pressurized gas. This gas can be hydrogen under high pressure. High pressure is understood here to mean a pressure of up to 1000 bar.

[0041] Such a tank 1 comprises a structure 2 and a flexible shell 3. The structure is typically rigid and designed to withstand mechanical stresses, which can be significant due to high pressures. The shell 3, or liner, rests on the structure 2 and is designed to ensure gas tightness.

[0042] According to one feature, the envelope 3 comprises at least two alveoli 4. An alveoli 4 extends mainly along a first axis X. An alveoli 4 has, perpendicular to the first axis X, a substantially constant alveoli cross-section along the first axis X.

[0043] Structure 2 extends along the first axis X and has, perpendicular to the first axis X, a ladder-like structural section. This ladder is complementary to the arrangement of cells 4. Structure 2 comprises an outer wall 8 closed upon itself and surrounding the outer periphery of said at least two assembled cells 4. Thus, the cross-section of the outer wall 8 substantially reproduces the periphery of the arrangement of cells 4. Structure 2 further comprises, for each pair of neighboring cells 4, an inner wall 9. This inner wall 9, which forms a rung of the ladder, separates the cells 4 of the pair and is integral with the outer wall 8 at both ends of the inner wall 9, so as to form a tension between the two instances of the outer wall 8. Thus, the structural section follows the cross-section of said cells 4, surrounding them externally.

[0044] According to another feature, a cell 4 has, perpendicular to the first axis X, a cell section substantially constant along the first axis X.

[0045] For the single-layer embodiment of [Fig. 1], the structural section has cells delimited by two passages of the outer wall 8, for the upper and lower sides of the cell, and by two adjacent inner walls 9 for the left and right sides of the cell. Exceptionally, the outermost cells 4 are surrounded by cells also bordered on one outer side by the outer wall 8.

[0046] For the two-layer embodiment of [Fig. 2], the structural section has two layers of boxes. The structural section also includes a central internal wall separating the two layers.

[0047] In all cases, the structural section substantially reproduces the section of the arrangement of alveoli 4.

[0048] Structure 2 is shown in Figures 7 and 8, adapted to the first embodiment of the reservoir in [Fig. 1], comprising a single layer of cells 4. The set of cells 4, according to this same first embodiment, is shown in [Fig. 3]. [Fig. 4] illustrates in sectional view the interlocking assembly of the cells 4 and structure 2.

[0049] Such an arrangement with cells 4, placed side by side in a configuration, allows, each cell being individually capable of withstanding the pressure due to the balanced cross-section of a cell 4, nevertheless the creation of a substantially flat reservoir 1, extending in both directions X and Y. The cells 4 are placed side by side in parallel. The particular conformation of the structure 2, with a ladder-like structural cross-section, allows the cells 4 to be held together and Each 4-cell assembly with the structural box allows it to withstand high gas pressures.

[0050] Such a flat arrangement is particularly advantageous for integrating such a tank 1 into a motor vehicle.

[0051] According to another feature, more particularly illustrated in [Fig. 3] or 5, each cavity 4 comprises a main extension tube 5 along the first axis X. This tube 5, prismatic in that its cross-section is repeated along the entire length of the first axis X, is preferably produced by extrusion. This tube 5 provides a seal on four sides. The tube 5 is then closed by means of two covers 6, 7, substantially flat along a plane perpendicular to the first axis X. These covers 6, 7 are preferably produced by injection molding, each positioned at one end of the tube 5. They are assembled in a leak-proof manner. The assembly is preferably carried out by welding. The welding can be carried out by any welding method. However, the welding is preferably carried out by hot air welding or mirror welding.Using one of these two assembly methods advantageously allows the assembly of all the lids 6 of all the adjacent tubes 5 in a single operation. [Fig. 11] shows the cross-sectional detail of the assembly of a tube 5 with a lid 6, to close a cavity 4.

[0052] According to another feature, all the lids 6, 7 at one end are made of the same material. All the lids 6 on one side are advantageously aligned in the same plane. Also, since all the tubes 5 are adjacent, the lids of two neighboring cells 4 are adjacent. Therefore, it is advantageous to make all the lids 6, 7 on the same side, corresponding to the same end of the tubes 5, in a single flat piece. The hot air welding process advantageously allows the lid / tube assembly to be carried out from the outside and thus together for all the tubes 5.

[0053] According to another characteristic, the alveoli 4 are all substantially identical and extend side by side parallel.

[0054] According to a first embodiment, illustrated in Figures 1, 3, 4, 9, 18 and 19, the cells 4 extend over a layer. This extension occurs along a second axis Y substantially perpendicular to the first axis X. This allows the reservoir 1 to have a substantially planar extension.

[0055] According to a second embodiment, illustrated in Figures 2, 5, 6, 10, 20 and 21, the cells 4 extend side by side parallel to each other in two layers. The extension occurs along the second Y axis. The layers are stacked along a third Z axis perpendicular to the first two axes X and Y.

[0056] More particularly in the second embodiment, the presence of two superimposed layers of cells 4 advantageously allows for the creation of a substantially central passage in an X, Y plane between the cells 4. According to another This characteristic passage is advantageously used to accommodate at least one stiffener 10. This stiffener 10 is advantageously positioned between the two layers. A stiffener 10 extends primarily along any direction within the X, Y plane. A stiffener 10 extends preferentially along the first axis X, between the two ends of the tank 1. A stiffener 10 can typically be made of metallic material or, alternatively, of high-strength composite material. It typically takes the form of a bar with a small cross-section, so as to fit easily between the cells 4, whose length is substantially equal to the length of the tank 1, in order to resist the forces, primarily tensile, along the axis of the stiffener 10.

[0057] A stiffener 10 is interposed between the wall of a tube 5 and the structure 2, here an internal wall 9. A series of stiffeners 10 can be inserted, as illustrated in figures 6, 10, 14, 20 or 21, between the upper cavity and the structure or between the lower cavity and the structure 2. Two series of stiffeners 10 can also be introduced, as illustrated in figures 5 or 15, between the upper cavity and the structure and between the lower cavity and the structure 2.

[0058] According to another feature, the cross-section of a cell 4 is substantially rectangular or oblong, preferably substantially rectangular with rounded corners. Such a rectangular shape allows a plurality of cells to be arranged side by side. The rounded corners also allow for better distribution of stresses in the composite of the structure 2 and in the plastic of the casing 3. The rounded corners simplify manufacturing, while remaining substantially rectangular. In order to better withstand the significant stresses related to pressure, the shape of the outermost cells can be more rounded towards the outside of the reservoir 1, as illustrated in Figures 3 and 4. Such a feature is not mandatory, as illustrated in [Fig. 6].

[0059] The primary function of the enclosure 3 is to ensure gas tightness. For this purpose, the enclosure 3 is advantageously made of plastic, such as PA6.

[0060] The primary function of structure 2 is to ensure the mechanical strength of tank 1, to support the casing 3, and to withstand the effects of high pressures. All of this can be achieved with metallic materials. One objective of tank 1, when intended for vehicle mounting, is to be lightweight. Therefore, according to another characteristic, structure 2 is preferably made of a lighter composite material. Structure 2 comprises a fabric of woven, non-woven, braided, or wound fibers impregnated in a curable resin.

[0061] The fibers of the fabric can be glass, carbon, Kevlar, or any other material. The fiber fabric can be produced in any embodiment. Thus, a casing can be made for each cell. According to another characteristic, the fiber fabric, which forms the framework of structure 2, is preferably made in one piece. This This can be achieved through weaving, interweaving, braiding, or winding. This method eliminates the need for sewing or gluing and results in a much stronger structure.

[0062] According to another feature, the fiber web, which forms the reinforcement of structure 2, is woven with an irregular warp and weft distribution. This feature allows the strength of the fiber web to be adapted to the potentially irregular distribution of stresses.

[0063] According to another feature, the casing 3, on all or part of its outer surface, opposite the structure 2, includes grooves. These grooves form channels. Indeed, the space between structure 2 and casing 3 is very small. Therefore, when the fiber fabric is placed around the cells of the casing, the gap between the two is small. The presence of the grooves, by creating channels that locally increase this gap, facilitates the introduction of the curable resin.

[0064] The invention further relates to a method for manufacturing such a reservoir 1. This method comprises the following operations. In a first step, a tube 5 is manufactured for each of the cells 4. Given the prismatic shape and constant cross-section, this manufacturing is preferably carried out by extrusion. The tubes 5 thus obtained are then arranged side by side, according to the desired final arrangement. In a second step, the fiber web of the structure 2, having a ladder-like structural cross-section corresponding to the arrangement of the tubes 5, is threaded around the tubes 5, its outer wall 8 surrounding the arrangement of the tubes 5 and its inner walls 9 being inserted between the adjacent tubes 5. In a third step, the end caps 6, 7 are then welded to each end of each tube 5. Alternatively, the end caps 6 can be welded on one side before the threading step.However, at least the 7 lids on the second side must be welded after threading. Then, in a fourth step, the fiber fabric is impregnated with a curable resin. This impregnation can be carried out by infusion or by RTM or C-RTM injection.

[0065] The invention has been illustrated and described in detail in the drawings and the preceding description. This description is to be considered illustrative and given by way of example and not as limiting the invention to this single description. Numerous embodiments are possible. List of reference signs

[0066] 1: reservoir,

[0067] 2: structure,

[0068] 3: envelope,

[0069] 4: alveolus,

[0070] 5: tube,

[0071] 6: first operculum,

[0072] 7: second lid,

[0073] 8: outer wall,

[0074] 9: inner wall,

[0075] 10: stiffener,

[0076] 11: first collector,

[0077] 12: second collector,

[0078] 13: first upper extension,

[0079] 14: first lower extension,

[0080] 15: second upper extension,

[0081] 16: second lower extension,

[0082] 17: first linear groove,

[0083] 18: second linear groove,

[0084] 19: first linear key,

[0085] 20: second linear key,

[0086] 21: first driving,

[0087] 22: second driving,

[0088] 23: valve,

[0089] 24: first connection,

[0090] 25: second connection,

[0091] 26: insert,

[0092] 27: O-ring,

[0093] 28: screw.

Claims

Demands

1. A reservoir (1) for pressurized gases, such as hydrogen, comprising a structure (2) and a flexible casing (3), wherein the casing (3) comprises at least two cells (4), one cell (4) extending along a first axis (X), and wherein the structure (2) extends along the first axis (X) and has, perpendicular to the first axis (X), a ladder-structure section, comprising an outer wall (8) surrounding the outer periphery of said at least two cells (4), and for each pair of adjacent cells (4), an inner wall (9) separating the cells (4) of the pair, and being integral, at its two ends, with the outer wall (8), characterized in that each cell (4) comprises a tube (5) along the first axis (X), a first operculum (6) disposed at one end of the tube (5), and a second operculum (7) disposed at a second end of the tube (5), assembled in a sealed manner at the end.

2. Reservoir (1) according to claim 1, wherein a cell (4) has, perpendicular to the first axis (X), a substantially constant cell section along the first axis (X).

3. Tank (1) according to any one of claims 1 or 2, wherein the tube (5) is preferably made by extrusion, and in which the first operculum (6) and the second operculum (6) are substantially flat along a plane perpendicular to the first axis (X), preferably made by injection, and assembled preferably by welding, more preferably by hot air welding or by mirror welding.

4. Reservoir (1) according to claim 3, wherein all the lids (6, 7) of one end are made of material.

5. Reservoir (1) according to any one of claims 1 to 4, wherein said at least two cells (4) are substantially identical and extend side by side parallel, in a layer, along a second axis (Y) substantially perpendicular to the first axis (X), so that the reservoir (1) has a substantially flat extension.

6. Reservoir (1) according to any one of claims 1 to 5, wherein said at least two cells (4) are substantially identical and extend side by side parallel, in two layers, along the second axis (Y).

7. Reservoir (1) according to claim 6, further comprising at least one stiffener (10) disposed between the two layers, preferably parallel to the first axis (X).

8. Tank (1) according to any one of claims 1 to 7, wherein the structure (2) is made of composite material, and comprises a fabric of woven, non-woven, braided or wound fibers impregnated in a curable resin.

9. Reservoir (1) according to claim 8, wherein the fibre fabric is made in one piece.

10. Reservoir (1) according to any one of claims 8 or 9, wherein the fibre fabric is woven with an irregular warp and weft distribution, in order to adapt its strength to the distribution of stresses.

11. Reservoir (1) according to any one of claims 8 to 10, wherein the casing (3) includes surface grooves to facilitate the introduction of the curable resin between the casing (3) and the fiber fabric.

12. A method for manufacturing a tank (1) according to any one of claims 8 to 11, characterized in that it comprises the following operations: manufacturing, for each of said at least two cells (4), of a tube (5), preferably by extrusion, arranging the tubes (5) side by side, threading the fiber web of the structure (2) around the tubes (5), welding two caps (6, 7), at each end of each tube (5), impregnating the fiber web with a curable resin.

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