Tank for pressurized gas

Abstract

Pressurized Gas Reservoir The invention relates to a pressurized gas reservoir (1), particularly for hydrogen, comprising a composite structure (2) and a sealing casing (3), wherein the sealing casing (3) comprises at least two parallel tubes (4) extending substantially along a first direction (X), and, at each end of the tubes (4), a common end shell (5, 6) sealing all the tubes (4), and in that the structure (2) comprises an elementary structure (2e) around each tube (4) and an overall structure (2g) around the assembly of the tubes (4) and the end shells (5, 6). The invention further relates to a method for constructing such a reservoir (1). Figure for the abstract: Figure 1

Description

Title of the invention: Reservoir for pressurized gas technical field

[0001] The invention relates to a tank for the storage of gas under pressure. Previous technique

[0002] A pressurized gas tank is typically used to store a gas on board a vehicle. The storage pressure of said gas can be high, up to pressures of around 1000 bar.

[0003] The gas is, for example, hydrogen intended for the propulsion of said vehicle, either by direct combustion in a hydrogen engine, or by the production of electricity within a fuel cell.

[0004] Such a tank, while withstanding pressure-related stresses, must remain lightweight so as not to increase the vehicle's overall weight. Therefore, such a tank is, in a known manner, made of composite material. One known embodiment uses a composite structure comprising fibers embedded in a resin matrix. This structure provides the tank's framework, ensuring its shape and guaranteeing its resistance to mechanical stresses. However, such a material cannot be gas-tight. Therefore, the structure is lined, over its entire internal surface, by a sealing jacket or liner made of thermoplastic material, ensuring gas tightness.

[0005] For the purposes of integrating the tank into a vehicle, it is advantageous for the tank to have a flattened shape. A spherical or cylindrical shape is best suited to providing uniform resistance to the mechanical stresses caused by pressure. Conversely, a flattened shape results in mechanical stresses that increase the further one deviates from a spherical shape.

[0006] Also, embodiments are sought to obtain a flattened tank. Summary of the invention

[0007] The invention proposes to address this problem ingeniously by means of parallel tubes and an ingenious embodiment of the structure.

[0008] For this purpose, the invention relates to a pressurized gas reservoir, in particular for hydrogen, comprising a composite structure and a sealing envelope, wherein the sealing envelope comprises at least two parallel tubes extending substantially along a first direction, and at each end of the tubes a common extremal shell, sealing all the tubes hermetically, and in that the structure comprises an elementary structure around each tube and an overall structure around the assembly of the tubes and the extremal shells.

[0009] Specific features or embodiments, usable alone or in combination, are:

[0010] - the tubes are made by extrusion,

[0011] - the outer shells are made by injection,

[0012] - the end shells are assembled to the ends of the tubes by welding,

[0013] - the elementary structure is achieved by filament winding around the tube and / or the overall structure is achieved by filament winding around the assembly of tubes and extremity shells,

[0014] - the sealing envelope further comprises an intermediate piece, incorporating the shape of the cross-section of the assembly of tubes interposed and welded between the ends of the tubes and an extremity shell,

[0015] - an extremal tube has a partially circular cross-section, preferably roughly in the shape of a "D",

[0016] - an intermediate tube has an oblong cross-section, preferably rectangular with rounded corners.

[0017] The invention also relates to a method for manufacturing a pressurized gas tank, in particular for hydrogen, comprising a composite structure and a sealing casing, comprising the following steps:

[0018] - manufacturing tubes by extrusion, two end tubes and at least zero tubes intermediaries,

[0019] - creation of an elementary structure around each tube by winding filamentous,

[0020] - parallel assembly of tubes,

[0021] - welding an end shell to each end of the tubes, preferably by inserting an intermediate piece,

[0022] - realization of an overall structure around the assembly of the tubes and shells extremities by filament winding. Brief description of the drawings

[0023] 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:

[0024] [Fig. 1] shows, in exploded perspective view, a first end of a reservoir according to the invention,

[0025] [Fig.2] shows, in exploded perspective view, the other end of the reservoir of the [Fig.1],

[0026] [Fig.3] shows, in sectional view along a plane passing through the X axes of the tubes, the assembled tank of [Fig.1],

[0027] [Fig.4] shows, in perspective view, a completed tank. Description of the implementation methods

[0028] With reference to figures 1 to 3, the invention relates to a reservoir 1 for pressurized gas, in particular hydrogen.

[0029] In order to withstand the high pressures imposed by the gas, the tank 1 includes a structure 2. To avoid increasing the weight and to facilitate its loading onto a vehicle, this structure 2 is preferably made of composite material. To ensure gas tightness, which structure 2 cannot provide, particularly in the case of hydrogen, which has a very small molecule, the tank 1 also includes a sealing jacket 3.

[0030] According to an ingenious feature, the sealing envelope 3 comprises at least two parallel tubes 4 extending substantially along a first direction X. The sealing envelope 3 further comprises two end shells 5, 6. At each end of the tubes 4, an end shell 5, 6, common to all the tubes 4, seals all the tubes 4 airtight. According to this same feature, the structure 2 comprises an elementary structure 2e around each tube 4 and an overall structure 2g around the assembly of the tubes 4 and the end shells 5, 6.

[0031] According to another feature, the tubes 4 are manufactured by extrusion. This feature is particularly advantageous because extrusion allows for the simple and industrial production of a single tube per meter, with any cross-section and any length. It will become apparent later that an elementary structure 2e, surrounding a tube 4, can also be manufactured on demand, to any desired length. Thus, extrusion makes it possible to produce tubes 4, and therefore tanks 1, of any length, simply and industrially.

[0032] According to another feature, the extremal shells 5, 6 are made by injection.

[0033] In order to ensure the desired gas tightness, the sealing envelope 3 and therefore all its components 4, 5, 6, 7, 8 are advantageously made of thermoplastic material, such as PA6 or any other plastic material of this type.

[0034] According to another feature, the extremal shells 5, 6 are assembled to the ends of the tubes 4 by welding.

[0035] Reference sign 2 designates the structure in a generic way, as well as all its parts 2e and 2g.

[0036] According to another feature, the structure 2 is produced in two stages, in two successive layers. On the one hand, an elementary structure 2e is produced by filament winding around each tube 4, taken separately. The elementary structure 2e is produced by winding around the X-axis of the tube 4 by tilting the winder at + / - a° relative to the X-axis, a being between 45° and 90°, preferably between 80° and 90°, so as to cross the filaments. The winder is regularly offset along the tube 4 relative to the X axis, in order to cover the tube 4 over almost its entire length.

[0037] Filament winding is a known technique for making a composite. It consists of winding a filament, such as a wire, a strip, ..., made of fibers, generally of glass or carbon, coated with a thermosetting or thermoplastic resin in an uncured form during winding, around a shape, a mold or here a tube 4, and then curing it afterwards.

[0038] Once each tube 4 is equipped by filament winding with its elementary structure 2e, all the tubes 4 are joined together. They are closed by the extremal shells 5, 6. The assembly comprising the tubes 4 and the extremal shells 5, 6 receives an overall structure 2g formed by filament winding around the assembly of the tubes 4 and the extremal shells 5, 6.

[0039] The overall structure 2g is formed by winding it around the assembly comprising the tubes 4 and the shells 5, 6 welded to the tubes 4. The winding then occurs along the two directions of the plane of the reservoir 1: the X axis and the Y axis. The overall structure 2g covers the entire reservoir 1 and particularly the shells 5, 6 not covered by the elementary structures 2e. At the level of the elementary structures 2e, the overall structure 2g forms a second layer of composite.

[0040] The shells 5, 6 are preferably joined to the ends of the tubes 4 by welding. This welding can be carried out using any welding technology, preferably autogenous.

[0041] Due to constraints, mainly related to the injection molding of the shells 5, 6, direct welding can be difficult. Therefore, according to another feature, the sealing casing 3 further includes an intermediate piece 7, 8. This intermediate piece 7, 8 is substantially flat and substantially follows the shape of the cross-section of the tube assembly 4. Such an intermediate piece 7 is inserted and welded between a first end of the tubes 4 and a first end shell 5. Another intermediate piece 8 is inserted and welded between the other end of the tubes 4 and a second end shell 6.

[0042] The profile of an intermediate piece 7, 8, more particularly visible in [Fig.3], is designed to, on the tube side 4, join the walls of two adjacent tubes 4 while ensuring their sealing, and, on the extreme shell side 5, 6, connect in a sealed manner to the edge of the extreme shell 5, 6. An objective is to have a continuous and closed thickness of the sealing envelope 3.

[0043] The tubes, generically referenced as 4, are distinguished into outer tubes 4e, arranged on each side of the stack of tubes 4, along the Y-axis, and into n tubes Intermediate tubes 4i are arranged between the extreme tubes 4e. n is a positive integer or zero. The choice of n allows the width of the reservoir 1 to be determined at will.

[0044] The cross-section of a tube 4, 4e, 4i can be arbitrary. This cross-section is substantially constant along the X-axis of the tube 4. A circular cross-section offers the best resistance to pressure. A rectangular cross-section optimizes the usable gas volume. However, excessively sharp edges risk creating damaging points of rupture and are therefore avoided.

[0045] Also, in order to optimize the filling volume, according to another characteristic, an intermediate tube 4i has an oblong cross-section, preferably rectangular with rounded corners. The pressure resistance of an intermediate tube 4i is also ensured by the two tubes 4 adjacent to it.

[0046] On the contrary, to optimize pressure resistance, according to another characteristic, an extremal tube 4e has a partially circular cross-section on the side where the tube 4e is free of neighboring tubes and a substantially straight cross-section on the side where it is adjacent to an adjacent tube 4. Also, an extremal tube 4e preferably has a cross-section substantially in the shape of a "D". Here too, to avoid fracture initiation points, the two edges appearing at the two corners of the "D" are advantageously rounded.

[0047] The invention further relates to a method of manufacturing a tank 1 for pressurized gas, in particular hydrogen, comprising a composite structure 2 and a sealing envelope 3.

[0048] Such a process comprises the following steps. In a first step, the tubes 4 are manufactured, preferably by extrusion. Here, two dies are used: a possible die with a substantially rectangular cross-section for the possible intermediate tubes 4i and a die with a "D" cross-section for the two end tubes 4e. A reservoir 1 requires two end tubes 4e and n intermediate tubes 4i, n being a positive integer, which may be zero. In a second step, each tube 4, 4e, 4i is surrounded, by filament winding, by an elementary structure 2e, reproducing its cross-sectional shape. In a third step, the tubes 4, 4i, 4e, equipped with their elementary structure 2e, are assembled, their X axis being parallel, in the final configuration of the tank 1. In a fourth step, an extremal shell 5, 6 is welded to each end of the tubes 4 so as to close the volume of the tank 1 in a hermetic manner.This assembly is preferably carried out by inserting an intermediate piece 7, 8 between tubes 4 and shells 5, 6. Once this assembly of tubes 4 and the extreme shells 5, 6 has been carried out, a fifth step creates an overall structure 2g around it, by filament winding.

[0049] The invention has been illustrated and described in detail in the preceding drawings and description. The latter 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

[0050] 1: reservoir,

[0051] 2: structure,

[0052] 2nd: elementary structure,

[0053] 2g: overall structure,

[0054] 3: sealing casing,

[0055] 4: tube,

[0056] 4th: extremal tube,

[0057] 4i: intermediate tube,

[0058] 5, 6: extreme shell,

[0059] 7, 8: intermediate piece.

Claims

Demands

1. A reservoir (1) for pressurized gas, in particular hydrogen, comprising a composite structure (2) and a sealing shell (3), characterized in that the sealing shell (3) comprises at least two parallel tubes (4) extending substantially along a first direction (X), and, at each end of the tubes (4), a common extremal shell (5, 6), sealing all the tubes (4) tightly, and in that the structure (2) comprises an elementary structure (2e) around each tube (4), and an overall structure (2g) around the assembly of the tubes (4) and the extremal shells (5, 6).

2. Reservoir (1), according to claim 1, wherein the tubes (4) are made by extrusion.

3. Reservoir (1) according to any one of claims 1 or 2, wherein the extremal shells (5, 6) are made by injection.

4. Tank (1) according to any one of claims 1 to 3, wherein the extremal shells (5, 6) are assembled to the ends of the tubes (4) by welding.

5. Reservoir (1) according to any one of claims 1 to 4, wherein the elementary structure (2e) is made by filament winding around the tube (4) and / or the overall structure (2g) is made by filament winding around the assembly of the tubes (4) and the extremal shells (5, 6).

6. Tank (1) according to any one of claims 1 to 5, wherein the sealing envelope (3) further comprises an intermediate piece (7, 8), having the shape of the cross-section of the set of tubes (4), interposed and welded between the end of the tubes (4) and an extremal shell (5, 6).

7. Reservoir (1) according to any one of claims 1 to 6, wherein an extremal tube (4e) has a partially circular cross-section, preferably substantially in the shape of a “D”.

8. Reservoir (1) according to any one of claims 1 to 7, wherein an intermediate tube (4i) has an oblong cross-section, preferably rectangular with rounded corners.

9. A method for manufacturing a tank (1) for pressurized gases, in particular hydrogen, comprising a composite structure (2) and a sealing envelope (3), characterized in this respect by the following steps: - manufacturing of tubes (4) by extrusion, two end tubes (4e) and at least zero intermediate tubes (4i), - creation of an elementary structure (2e) around each tube (4) by filament winding, - parallel assembly of tubes (4), - welding of an end shell (5, 6) to each end of the tubes (4), preferably by inserting an intermediate piece (7, 8), - realization of an overall structure (2g) around the assembly of the tubes (4) and the extremal shells (5, 6) by filament winding.

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