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 a 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, where the envelope comprises at least two cells, one cell extending along a first axis and the structure extending along the first axis and presenting, 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] - the reservoir further comprises a first collector extending mainly along a second axis, substantially perpendicular to the first axis, and arranged in contact with all the first extremities of said at least two alveoli and a second collector extending principally along the second axis and disposed in contact with all the second extremities of said at least two alveoli, each alveolus being fluidly connected to at least one collector,

[0010] - a lid is adhered by overmolding to the adjacent collector,

[0011] - a collector further comprises a conduit extending along the second axis on the entire length of the manifold, said pipe being fluidly connected to a tank filling / draining valve and / or being fluidly connected to at least one cell,

[0012] - the reservoir further includes stiffeners connecting the first manifold and the second collector, 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] - a collector is made of metallic material, preferably light alloy or in composite material exhibiting high mechanical resistance, at least on its external surface.

[0015] 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, setting up the collectors and impregnating the fiber fabric with a hardenable resin. Brief description of the drawings

[0016] 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:

[0017] [Fig-1] shows, in perspective view, a reservoir according to a first embodiment,

[0018] [Fig.2] shows, in perspective view, a reservoir according to a second embodiment,

[0019] [Fig.3] shows, in perspective view, an assembly step of the tank of the [Fig.1],

[0020] [Fig.4] shows, in a cross-sectional view perpendicular to the first X axis, the reservoir of the [Fig.l],

[0021] [Fig.5] shows, in perspective view, an assembly step of the tank of the [Fig.2],

[0022] [Fig.6] shows, in a cross-sectional view perpendicular to the first X axis, the reservoir of the [Fig.2],

[0023] [Fig.7] shows, in perspective view, the structure of the tank of [Fig.1], before its assembly,

[0024] [Fig.8] shows, in perspective view, the structure of the tank of [Fig.1], after its assembly,

[0025] [Fig.9] shows, in a cut-off view perpendicular to the second axis Y, the reservoir of the [Fig.1],

[0026] [Fig. 10] shows, in a cut-off view perpendicular to the second Y axis, the reservoir of the [Fig.2],

[0027] [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,

[0028] [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,

[0029] [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,

[0030] [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,

[0031] [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,

[0032] [Fig. 16] shows, in detail, the connection of a socket to a conduit, according to a first embodiment,

[0033] [Fig. 17] shows, in detail, the connection of a socket to a conduit, according to another embodiment,

[0034] [Fig. 18] shows, in partial perspective view, a primary collector and enclosure assembly, according to a first embodiment,

[0035] [Fig. 19] shows, in partial perspective view, a second collector and casing assembly, according to a first embodiment,

[0036] [Fig.20] shows, in partial perspective view, a primary collector and enclosure assembly, according to a second embodiment,

[0037] [Fig.21] shows, in partial perspective view, a second collector assembly and envelope, according to a second embodiment. Description of the implementation methods

[0038] 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.

[0039] 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.

[0040] 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.

[0041] The 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 an arrangement of cells 4. The 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 cell arrangement 4. The 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.

[0042] According to another feature, a cell 4 has, perpendicular to the first axis X, a cell section substantially constant along the first axis X.

[0043] 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.

[0044] 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.

[0045] In all cases, the structural section substantially reproduces the section of the arrangement of alveoli 4.

[0046] 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.

[0047] 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, 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.

[0048] Such a flat arrangement is particularly advantageous for integrating such a tank 1 into a motor vehicle.

[0049] 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.

[0050] According to another feature, the reservoir 1 further comprises a first manifold 11 and a second manifold 12.

[0051] The first collector 11 extends mainly along a second axis Y, substantially perpendicular to the first axis X. It is arranged in contact with all the first ends of said at least two alveoli 4. Similarly, the second collector 12 extends mainly along the second axis Y. It is arranged in contact with all the second ends of said at least two alveoli 4.

[0052] According to another feature, a soffit 6, 7 is advantageously adhered to the adjacent manifold 11, 12. This advantageously allows for a perfect seal of the assembly. The formation of the conduit 24, 25, which ensures fluid communication between the cavity 4 and the manifold 11, 12, can be achieved by a gas co-injection process.

[0053] In order to constitute a reservoir, each cell 4 is fluidly connected to at least one collector 11, 12. This is achieved, for example, by means of a conduit 24, 25, piercing at least one operculum 6, 7 of the cell 4 and fluidly connected to a collector 11, 12.

[0054] According to another feature, a manifold 11, 12 further comprises a conduit 21. This conduit 21 is integrated into the manifold 11, 12. It extends along the second Y-axis along the entire length of the manifold 11, 12. This conduit 21 is fluidly connected to a valve 23, which can be used to perform filling and / or The reservoir 1 is drawn from the main line. Furthermore, alternatively or complementaryly, this pipe 21 is fluidly connected to at least one cell 4, preferably to all the cells 4. The cells 4 are sealed between each other. Thus, they constitute elementary reservoirs. Reservoir 1 is made up of the assembly of these elementary reservoirs. These elementary reservoirs must be connected together. This is advantageously achieved by a pipe 21, 22 located in one of the two collectors 11, 12.

[0055] According to a first embodiment, the first pipe 21 of a first manifold 11 is fluidly connected to a valve 23 and to at least one cell 4, via a first connection 24, linking the first pipe 21 to the inside of at least one cell 4 by passing through its adjacent opening 6. This allows the reservoir 1 to be connected to the outside. According to the same embodiment, the second pipe 22 of the other manifold 12 is fluidly connected to all the cells 4, via a series of second connections 25, one per cell, a second connection 25 linking the second pipe 22 to the inside of a cell 4 by passing through its adjacent opening 7. This allows all the cells 4 to be connected to each other. This is illustrated, for example, in [Fig. 9] or [Fig. 19].

[0056] Alternatively or complementarily, the first conduit 21 can connect several cells 4, and preferably all of them, via initial connections 24. This is particularly illustrated in [Fig. 18] for a single-layer tank with 4 cells and in [Fig. 20] for a double-layer tank with 4 cells. Similarly, the second conduit 22 can be connected to a filling / draw-off valve.

[0057] In the embodiment where one of the pipes 21, 22 provides both the connection to the outside via a valve 23 and the interconnection of all the cells 4, it is possible not to have a second pipe in the other manifold. This is illustrated in [Fig. 10].

[0058] In the embodiment of [Fig. 2], where the cells are arranged in two superimposed layers, the conduit(s) 21, 22 are advantageously doubled, so that one conduit 21 is positioned opposite each of the layers. This is illustrated more particularly in Figures 2, 10 and 20.

[0059] Figure 16 illustrates a detail of a fluidic junction between a pipe 21 disposed in a collector 11 and a cavity 4 by means of a connection 24. This is, for example, achieved by means of an insert 26, carrying the connection 24, overmolded in the operculum 6. The insert 26 has a shape complementary to a bore made in the collector 11 and into which it is engaged, so as to open the end of the connection 24 into the interior of the pipe 21. The seal can be improved by means of at least one O-ring 27 disposed between the insert 26 and the bore.

[0060] According to another embodiment, more particularly illustrated in [Fig. 17], the conduit 21 is made of material, typically by overmolding, with the operculum or opercula 6. Such an embodiment guarantees sealing.

[0061] More particularly, in the embodiment of [Fig. 2], the presence of two superimposed layers of cells 4 advantageously creates a substantially central passage in an X, Y plane between the cells 4. According to another feature, this 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 X axis, between the two ends of the reservoir 1.

[0062] According to another feature, the stiffener(s) 10 connect the first collector 11 to the second collector 12, preferably parallel to the first axis X. The stiffeners 10 are advantageously fixed to the collectors 11, 12, for example by locking keys.

[0063] 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, of a length substantially equal to the length of the tank 1, so as to resist the forces, mainly in tension, along the axis of the stiffener 10.

[0064] 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.

[0065] 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].

[0066] 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.

[0067] 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.

[0068] According to another feature, a manifold 11, 12 is made of metallic material. Such a material provides strength to the reservoir 1. This material is preferably a lightweight alloy. Alternatively, it may be a composite material with high mechanical strength. A manifold 11, 12 advantageously exhibits high mechanical strength, at least on its external surface, in order to allow the structure 2 to be tensioned and fixed.

[0069] 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 covers on the second side must be welded after threading. In a fourth step, the collectors 11 and 12 are installed at the opposite end of the reservoir 1. Then, in a fifth 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.

[0070] 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

[0071] 1: reservoir,

[0072] 2: structure,

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[0098] 3: envelope, 4: alveolus, 5: tube, 6: first operculum, 7: second operculum, 8: outer wall, 9: inner wall, 10: stiffener, 11: first collector, 12: second collector, 13: first upper extension, 14: first lower extension, 15: second extension high, 16: second extension low, 17: first linear groove, 18: second linear groove, 19: first linear key, 20: second linear key, 21: first pipe, 22: second pipe, 23: valve, 24: first connection, 25: second connection, 26: insert, 27: O-ring, 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 the structure (2) extending along the first axis (X) and having, 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 a first 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 cross-section along the first axis (X)

3. Reservoir (1) according to any one of claims 1 or 2, wherein a tube (5) is preferably made by extrusion, the first liner (6) and the second liner (7) are substantially flat along a plane perpendicular to the first axis (X), preferably made by injection, and assembled by welding, preferably by hot air welding or by mirror welding.

4. Reservoir (1) according to claim 3, further comprising a first collector (11) extending mainly along a second axis (Y), substantially perpendicular to the first axis (X), and disposed in contact with all the first ends of said at least two cells (4) and a second collector (12) extending mainly along the second axis (Y) and disposed in contact with all the second ends of said at least two cells (4), each cell (4) being fluidly connected to at least one collector.

5. Reservoir (1) according to any one of claims 3 or 4, wherein a lid (6, 7) is adhered by overmolding to the adjacent collector (11, 12).

6. Reservoir (1) according to any one of claims 4 or 5, wherein a manifold (11, 12) further comprises a conduit (21) extending along the second axis (Y) over the entire length of the collector (11, 12), said conduit (21) being fluidly connected to a filling / draining valve (23) of the reservoir (1) and / or being fluidly connected to at least one cell (4).

7. Reservoir (1) according to any one of claims 4 or 5, further comprising stiffeners (10) connecting the first manifold (11) and the second manifold (12), preferably parallel to the first axis (X).

8. Tank (1) according to any one of claims 1 to 76, 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 any one of claims 1 to 8, wherein a collector (11, 12) is made of metallic material, preferably of light alloy or composite material having high mechanical strength, at least on its external surface.

10. A method for manufacturing a reservoir (1) according to any one of claims 8 to 9, 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 fabric of the structure (2) around the tubes (5), welding two caps (6, 7), at each end of each tube (5), setting up the collectors (11, 12) and impregnating the fiber fabric with a curable resin.

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