Pressurized gas containment jacket, pressurized gas tank and method for manufacturing a pressurized gas containment jacket associated

Abstract

Pressurized gas containment envelope, pressurized gas reservoir and method for manufacturing a pressurized gas containment envelope associated This pressurized gas containment envelope (12), comprises: - a first part (22), comprising a first shell (44), - a second part, comprising a second shell, - at least one intermediate part (26), disposed between the first (22) and the second part, along an assembly direction (A-A'), the intermediate part(s) (26) being attached to the first (22) and second parts, the first part (22), the second part and the at least one intermediate part (26) together delimiting an internal volume, the or at least one of the intermediate part(s) (26) comprising: - an intermediate shell (34), and - at least one pillar (36) elongated along an elongation direction (E-E'),connecting two opposite portions of the intermediate shell (34) and passing through the internal volume (28) perpendicular to the assembly direction (A-A'), the pillar (36) and the intermediate shell (34) being made of material. Figure for the abbreviation: Figure 1,

Description

Title of the invention: Pressurized gas containment envelope, associated pressurized gas tank and method of manufacturing a pressurized gas containment envelope

[0001] The present invention relates to a pressurized gas containment envelope. The invention relates to a pressurized gas tank comprising such an envelope as well as a method of manufacturing such an envelope.

[0002] In the field of means of transport, and in particular in automobiles, it may prove important to contain pressurized gas. This is all the more true with the rise of vehicles equipped with fuel cells, for which dihydrogen intended to power a fuel cell must be stored in the vehicle.

[0003] It is known to use cylindrical tanks for the containment of pressurized gas in vehicles. Such tanks are generally provided with a cylindrical containment casing, arranged inside a body of the tank, and intended to ensure the containment of the pressurized gas in the tank.

[0004] Such envelopes, and more generally such tanks, do not, however, give complete satisfaction due to their shape which is sometimes unsuitable for fitting out a vehicle.

[0005] It has then been proposed to use non-cylindrical tanks, and for example prismatic tanks. Such tanks generally have the shape of a flattened prism to improve the integration of the tank into the vehicle.

[0006] However, such tanks are not entirely satisfactory. Indeed, due to their non-cylindrical shape, the robustness of the tanks is reduced. It was then necessary to locally reinforce the tanks to improve their robustness, and to adapt the casings to such reinforcements. However, the manufacture of such casings is complex.

[0007] Furthermore, in order to ensure proper integration of an envelope into a vehicle, it is generally necessary to design and manufacture parts for the envelope that are specific to the vehicle. This can be particularly expensive.

[0008] Thus, one of the aims of the invention is to propose a gas containment envelope allowing easy integration into a vehicle while making it possible to obtain a robust tank that is not very complex to manufacture. Another aim of the invention is to propose such an envelope that is versatile and that can be adapted to different types of vehicles at a lower cost.

[0009] To this end, the invention relates to a pressurized gas containment envelope, comprising: - a first part, comprising a first shell, - a second part, comprising a second shell, - at least one intermediate part, arranged between the first and the second part, in an assembly direction, the intermediate part(s) being secured to the first and second parts,

[0010] the first part, the second part and the at least one intermediate part together delimiting an interior volume,

[0011] the or at least one of the intermediate part(s) comprising: - an intermediate shell, and - at least one pillar elongated in a direction of elongation, connecting two opposite portions of the intermediate shell and crossing the interior volume perpendicular to the assembly direction,

[0012] the pillar and the intermediate shell being made of one material.

[0013] Such an envelope, by the use of an intermediate part comprising a pillar, makes it possible to obtain an envelope capable of accommodating reinforcement elements of a tank. In addition, the pillar being integral with the intermediate shell, the simple assembly of the intermediate part to the first and second parts makes it possible to obtain such an envelope capable of accommodating at least one reinforcement. Finally, and as a variable number of intermediate parts can be assembled to the first and second parts, it is particularly easy to adapt the envelope to the vehicle on which the envelope is intended to be used, by simply modifying the number of intermediate parts secured between the first and second parts.

[0014] According to other advantageous aspects of the invention, the support envelope comprises one or more of the following characteristics, taken in isolation or in any technically possible combination:

[0015] - the envelope comprises a plurality of intermediate parts, adjacent according to the assembly direction;

[0016] - the at least one intermediate portion comprises a plurality of pillars, the plurality of pillars being aligned in a direction perpendicular to the assembly direction and to the elongation direction of said pillars;

[0017] - the at least one pillar is hollow, the pillar comprising a pillar wall, connected to the intermediate shell and delimiting a pillar cavity, the pillar and the intermediate shell delimiting two openings so that the pillar cavity opens on either side of the intermediate part;

[0018] - the envelope is such that:

[0019] - the first part comprises at least one first reinforcing rib secured to the first shell, said first reinforcing rib comprising a light extending parallel to the direction of elongation and opening on either side of the first part, and / or

[0020] - the second part comprises at least one second reinforcing rib integral with the second shell, said second reinforcing rib comprising a light extending parallel to the direction of elongation and opening on either side of the second part;

[0021] - the first part, the at least one intermediate part and the second part, are in alternating according to the assembly direction, formed from a material configured to be transparent to laser radiation and from a material configured to absorb laser radiation,

[0022] the first part, the at least one intermediate part and the second part, being secured to each other in the assembly direction by laser welding;

[0023] - the first part, the at least one intermediate part and the second part, are secured to each other in the assembly direction by edge-to-edge welding, a resistive sheet being arranged between adjacent welded edges of the first part, of the at least one intermediate part or of the second part; and

[0024] - the adjacent welded edges delimit between them an edge-to-edge welding plane oblique, extending obliquely relative to the assembly direction.

[0025] The invention further relates to a tank comprising a pressurized gas envelope as mentioned above, and a tank body arranged around the envelope, an internal face of the tank body being affixed to an external face of the envelope.

[0026] The invention further relates to a method of assembling a pressurized gas containment envelope, comprising the following steps:

[0027] - provision of a first part, a second part and at least one part in intermediate envelope;

[0028] - joining the intermediate part(s) to the first and second parts, the intermediate part(s) being arranged between the first part and the second part in the assembly direction.

[0029] The invention will be better understood on reading the description which follows, given solely by way of non-limiting example and made with reference to the drawings in which:

[0030] [Fig-1] [Fig.l] is a perspective view of a tank comprising a envelope according to the invention, during the manufacture of the tank;

[0031] [Fig.2] [Fig.2] is a cross-sectional view of the reservoir of [Fig.l] according to a sectional plan 1-1', the tank manufacturing being completed;

[0032] [Fig.3] [Fig.3] is a perspective view of the tank of [Fig.l] in its entirety; and

[0033] [Fig.4] [Fig.4] is a sectional view along plane 1-1' of a detail of the joining between two parts of an envelope according to an alternative embodiment to embodiment shown in Figures 1 to 3.

[0034] With reference to Figures 1 to 3, a pressurized gas reservoir 10 comprises a pressurized gas containment envelope 12. As visible in [Fig.2], the reservoir 10 further comprises a reservoir body 14 as well as at least one reservoir column 16.

[0035] The pressurized gas tank 10 is configured to contain a pressurized gas such as, for example, a reducing fuel gas and in particular pressurized hydrogen. The pressurized gas tank 10 is, for example, configured to contain a gas at a pressure greater than 200 bar and, for example, a gas at a pressure of 350 bar or a gas at a pressure of 700 bar. The pressurized gas tank 10 is further, for example, configured to contain a liquid, such as, for example, a liquid phase of the pressurized gas contained in the tank 10.

[0036] The pressurized gas tank 10 is for example intended to be installed in a vehicle and for example a motor vehicle. The pressurized gas tank 10 is for example configured to supply fuel to a fuel cell of the vehicle (not shown).

[0037] The reservoir body 14 forms, for example, a body volume 17 in which the casing 12 is housed. The reservoir body 14 comprises, for example, an internal face 18 defining the body volume 17. The reservoir body 14 is, for example, produced around the casing 12 so that the casing 12 is arranged in the reservoir body 14, the internal face 18 being, for example, affixed to an external face 20 of the casing.

[0038] The tank body 14 is for example made of composite. The composite from which the tank body 14 is made comprises, for example, a resin such as: an epoxy resin, or a resin made from at least one thermoplastic polymer chosen from the group consisting of polyolefins, in particular polypropylene, polyamides, in particular aliphatic polyamides, such as polycaprolactam PA 6, polyhexamethylene adipamide PA 6.6, polycarbonates, PAEK (Polyaryletherketone) which includes PEEK (polyetheretherketone) and PEKK (polyetherketoneketone), acrylic-based materials such as PMMA (in particular the resin known as ELIUM), PEI (Polyetherimide also known as ULTEM), PPS (Polyphenylene sulfide), ABS (acrylonitrile butadiene styrene), PLA (polylactic acid), TPU (thermoplastic polyurethane) and PET (polyethylene), and their mixtures.

[0039] The composite from which the tank body 14 is made comprises, for example, a reinforcement made of: fibers chosen from the group consisting of carbon fibers, Kevlar fibers, glass fibers, ceramic fibers, fibers of polymer material, for example thermoplastic, in particular fibers aramid or polyester, fibers of plant origin, in particular flax fibers, metallic fibers, the fibers preferably being carbon fibers, or a mixture of such fibers.

[0040] As visible in [Fig. 2], each tank column 16 extends into the body volume 17 and connects, for example, portions of the internal face 18 of the tank body 14 opposite each other relative to the body volume 17. In FIGS. 1 and 3, the columns 16 are shown during their installation and are then not yet secured to the tank body 14, the tank body 14 in particular not being formed.

[0041] Each tank column 16 is for example welded to the tank body 14 at each of the ends of the column 16 and / or made so as to form a single block with the tank body 14.

[0042] Each tank column 16 is for example made of composite. The composite from which each tank column 16 is made comprises, for example, a resin such as: an epoxy resin, or a resin made from at least one thermoplastic polymer chosen from the group consisting of polyolefins, in particular polypropylene, polyamides, in particular aliphatic polyamides, such as polycaprolactam PA 6, polyhexamethylene adipamide PA 6.6, polycarbonates, PAEK (Polyaryletherketone) which includes PEEK (polyetheretherketone) and PEKK (polyetherketoneketone), acrylic-based materials such as PMMA (in particular the resin known as ELIUM), PEI (Polyetherimide also known as ULTEM), PPS (Polyphenylene sulfide), ABS (acrylonitrile butadiene styrene), PLA (polylactic acid), TPU (thermoplastic polyurethane) and PET. (polyethylene), and their mixtures.The composite from which the tank body 14 is made comprises, for example, a reinforcement made of: fibers chosen from the group consisting of carbon fibers, Kevlar fibers, glass fibers, ceramic fibers, fibers of polymer material, for example thermoplastic, in particular aramid or polyester fibers, fibers of plant origin, in particular flax fibers, metal fibers, the fibers preferably being carbon fibers, or a mixture of such fibers.The composite from which each tank column 16 is made comprises, for example, a reinforcement made of: fibers chosen from the group consisting of carbon fibers, Kevlar fibers, glass fibers, ceramic fibers, fibers of polymer material, for example thermoplastic, in particular aramid or polyester fibers, fibers of plant origin, in particular flax fibers, metal fibers, the fibers preferably being carbon fibers, or a mixture of such fibers.

[0043] In a particular embodiment, the material of the reservoir columns 16 is the same as the material of the tank body 14.

[0044] In a variant not shown, the columns 16 are for example hollow.

[0045] As seen above, the envelope 12 is for example arranged in the body volume 17.

[0046] The casing 12 is configured to ensure the sealing of the tank 10 to the pressurized gas while the tank body 14 is configured to ensure resistance to the pressure of the pressurized gas.

[0047] As illustrated in [Fig. 3], the envelope 12 comprises a first part 22, a second part 24 and at least one intermediate part 26.

[0048] The first part 22, the second part 24 and the at least one intermediate part 26 are for example made of a thermoplastic material chosen from the list consisting of ABS (Acrylonitrile butadiene styrene), PA (polyamide), PE (polyethylene), PC (polycarbonate), PP (polypropene), PMMA (poly methyl acrylic methacrylate), PS (Expanded polystyrene), PBT (Polybutylene terephthalate). The material of the first part 22, the second part 24 and the at least one intermediate part 26 is for example more particularly chosen from the list consisting of: PA6 (Polycaprolactam), PAU (polyundecanamide) or PA12 (Nylon 12).

[0049] As will be described in more detail below, the thermoplastic material chosen to produce the first part 22, the second part 24 or the at least one intermediate part 26 may comprise an additive.

[0050] The envelope 12 comprises for example a plurality, and for example between one and five intermediate parts. In the embodiment of [Fig. 3], the envelope comprises three intermediate parts 26.

[0051] As illustrated in [Fig. 3], the at least one intermediate part 26 is arranged between the first 22 and the second 24 parts in an assembly direction A-A'. The intermediate part(s) 26 are secured to the first 24 and second 26 parts. As illustrated in [Fig. 1], when the envelope 12 comprises several intermediate parts 26, the intermediate parts 26 are adjacent in the assembly direction A-A'. One of the intermediate parts 26 is for example secured to the first part 22, another of the intermediate parts 26 is secured to the second part 24, the other possible intermediate parts 26 each being secured to intermediate parts 26 adjacent to them.

[0052] The first part 22, the second part 24 and the at least one intermediate part 26 together delimit an interior volume 28. The interior volume 28 thus delimited is configured to be occupied by the pressurized gas.

[0053] The first part 22, the second part 24 and the at least one intermediate part 26 are for example, alternately according to the assembly direction A-A', made of a material configured to be transparent to laser radiation and of a material configured to absorb laser radiation. Thus, one of two adjacent parts 22, 24, 26 of the envelope 10 is made of a material configured to be transparent to laser radiation, the other of the two adjacent parts 22, 24, 26 of the envelope 10 being made of a material configured to absorb laser radiation.

[0054] In the example of [Fig. 3], the first part 22 and the second part 24 are made of a material configured to absorb laser radiation. The intermediate parts 26 secured to these first 22 and second parts 24 are then made of a material configured to be transparent to laser radiation, the intermediate part 26 secured to said intermediate parts 26 then being made of a material configured to absorb laser radiation.

[0055] The first part 22, the at least one intermediate part 26 and the second part 24 are then, for example, secured to each other in the assembly direction A-A' by laser welding 14.

[0056] As illustrated in [Fig.2], a part 22, 24, 26, made of a material configured to be transparent to laser radiation, comprises a covering portion 30 covering a covered portion 32 of the part 22, 24, 26 adjacent thereto and being made of a material configured to absorb laser radiation. The first part 22, the at least one intermediate part 26 and the second part 24 are then secured by laser welding between the covering portion 30 and the covered portion 32 of adjacent parts 22, 24, 26.

[0057] The material configured to be transparent to laser radiation is for example made from one of the thermoplastic materials presented above, said thermoplastic material being devoid of light absorption additive.

[0058] The material configured to absorb laser radiation is for example made from one of the thermoplastic materials presented above, said thermoplastic material comprising a light absorption additive, such as for example carbon.

[0059] In a particular embodiment, the material configured to be transparent to laser radiation and the material configured to absorb laser radiation are made using the same thermoplastic material, the difference between these materials being that the material configured to absorb laser radiation is treated using a light absorption additive while the material configured to be transparent to laser radiation is not treated using such an additive.

[0060] As visible in [Fig.l], the at least one intermediate part 26 comprises an intermediate shell 34 and at least one pillar 36 elongated in a direction of elongation E-E'. The at least one intermediate part 26 comprises for example between two and eight pillars.

[0061] In the embodiment illustrated in Figures 1 to 3, the intermediate portion 26 comprises a plurality of pillars 36 and in particular five pillars. The plurality of pillars 36 is for example aligned in a direction perpendicular to the assembly direction A-A' and to the elongation direction E-E' of said pillars.

[0062] The intermediate shell 34 is for example of constant profile along the assembly direction A-A'. In the example of [Fig.l], the intermediate shell has an oblong-shaped profile along a plane normal to the assembly direction A-A', this profile being constant along the assembly direction A-A'.

[0063] The at least one elongated pillar connects two opposite portions of the intermediate shell 34 and passes through the interior volume 28 perpendicular to the assembly direction A-A'. The pillar 36 and the intermediate shell 34 are in particular made in one piece.

[0064] The interior volume 28 then extends inside the intermediate shell 34, around the or each pillar 36.

[0065] As visible in [Fig.l], the at least one elongated pillar 36 extends for example along a median plane P of the intermediate part 26, the plane P being orthogonal to the assembly direction A-A'.

[0066] As visible in [Fig. 2], the pillar 36 is hollow. The pillar 36 comprises in particular a pillar wall 38, connected to the intermediate shell 34, and delimiting a pillar cavity 40. A thickness of the pillar wall 38 is for example substantially equal to a thickness of the intermediate shell 34.

[0067] The pillar 36 and the intermediate shell 34 delimit, for each pillar 36, two openings 42 of the cavity of said pillar 40, so that the pillar cavity 40 opens on either side of the intermediate part 26.

[0068] As illustrated in [Fig. 2], a reservoir column 16 is housed in the cavity 40 of each pillar 36, the reservoir column 16 projecting from the cavity 40 on either side of the intermediate part 26, through the two openings 42 (the columns 16 are illustrated during their installation in Figures 1 and 3).

[0069] The first part 22 comprises a first shell 44. The first part 22 further comprises, for example, at least one first reinforcing rib 46.

[0070] The first part 22 and the intermediate part 26 adjacent to the first part 22 are for example secured to each other by securing the first shell 44 to the intermediate shell 34 of the adjacent intermediate part 26.

[0071] As illustrated in [Fig.l], a port 48 of the reservoir 10 is for example housed in the first part 22 to allow access to the interior volume 28, for example for filling and / or emptying the interior volume 28 with pressurized gas.

[0072] Each first reinforcing rib 46 is integral with the first shell 44. In particular, each first reinforcing rib 46 and the first shell 44 are, for example, made in one piece.

[0073] As illustrated in [Fig. 2], the reinforcing rib 46 comprises a lumen 50 extending parallel to the elongation direction E-E'. In other words, the lumen 50 extends parallel to the at least one pillar of the at least one intermediate part 26. The lumen 50 opens for example on either side of the first part 22.

[0074] A reservoir column 16 is for example housed in the slot 50 of each first reinforcing rib 46 and projects on either side of the slot 50 while being secured to the reservoir body 14.

[0075] The second part 24 comprises a second shell 52. The second part 24 further comprises, for example, at least one second reinforcing rib 54.

[0076] The second part 24 and the intermediate part 26 adjacent to the second part 24 are for example secured to each other by securing the second shell 52 to the intermediate shell 34 of the adjacent intermediate part 26.

[0077] As illustrated in [Fig.2], a port 48 of the reservoir 10 is for example housed in the second part 24 to allow access to the interior volume 28, for example for filling and / or emptying the interior volume 28 with pressurized gas.

[0078] Each second reinforcing rib 54 is integral with the second shell 52. In particular, each second reinforcing rib 54 and the second shell 52 are, for example, made in one piece.

[0079] As illustrated in [Fig. 2], the second reinforcing rib 54 comprises a lumen 56 extending parallel to the elongation direction E-E'. In other words, the lumen 56 extends parallel to the at least one pillar of the at least one intermediate part 26. The lumen 56 opens for example on either side of the second part 24.

[0080] A reservoir column 16 is for example housed in the slot 54 of each second reinforcing rib 54 and projects on either side of the slot 50 while being secured to the reservoir body 14.

[0081] A second embodiment of a pressurized gas containment envelope 12 will now be presented. According to this second embodiment, the envelope 12 differs from the previously presented embodiment by the following. Similar elements bear the same references.

[0082] In this second embodiment, the first part 22, the at least one intermediate part 26 and the second part 24 are not assembled by laser welding but are assembled along the assembly direction A-A' by edge-to-edge welding.

[0083] For this purpose, the parts 22, 24, 26 are not necessarily alternately formed from a material configured to be transparent to laser radiation and from a material configured to absorb the laser radiation. The parts 22, 24, 26 then also do not necessarily comprise a covering portion 30 and / or a covered portion 32.

[0084] According to this embodiment, and as illustrated in [Fig. 4], a resistive sheet 58 is arranged between adjacent welded edges 60 of the first part 22, of the at least one intermediate part 26 or of the second part 24. The welding of two parts 22, 24, 26 is then carried out by means of the resistive sheet and results in particular from a local fusion of the adjacent edges 60 on either side of the resistive sheet 58. [Fig. 4] illustrates the welding between adjacent edges 60 of the first part 22 and of the intermediate part 26.

[0085] The resistive sheet 58 is configured to be heated by the Joule effect and is for example made of carbon.

[0086] The adjacent edges 60 delimit between them an edge-to-edge welding plane S. As illustrated in [Fig.4], the edge-to-edge welding plane S is for example oblique relative to the assembly direction, that is to say that the edge-to-edge welding plane S is not orthogonal to the assembly direction A-A'. The welding plane forms for example an angle of between 0° and 80° relative to the assembly direction A-A' and in particular between 30° and 60°.

[0087] A third embodiment of a pressurized gas containment envelope 12 will now be presented. According to this third embodiment, the envelope 12 differs from the embodiments previously presented by the following. Similar elements bear the same references.

[0088] In this third embodiment, the first part 22, the at least one intermediate part 26 and the second part 24 are neither assembled by laser welding nor by edge-to-edge welding, but are assembled along the assembly direction A-A' by hot gas welding.

[0089] For this purpose, the parts 22, 24, 26 are not necessarily alternately formed from a material configured to be transparent to laser radiation and from a material configured to absorb the laser radiation. No resistive sheet is furthermore arranged between adjacent edges of the parts 22, 24, 26. Two adjacent parts may however comprise a covering portion 30 respectively a covered portion 32, just as in the first embodiment. Said adjacent parts are for example secured to each other using a weld of the covering portions 30 and covered 32 resulting from heating using a hot gas, such as hot air.

[0090] A method of manufacturing a pressurized gas containment envelope 12 as described above will now be presented.

[0091] In a first step, a first part 22, a second part 24 and at least one intermediate part 26 of the envelope 12 is provided.

[0092] During a second step, the intermediate part(s) 26 are secured to the first 22 and second 24 parts, the intermediate part(s) 26 being arranged between the first part 22 and the second part 24 in the assembly direction A-A'. When the envelope 12 comprises a plurality of intermediate parts 26, the adjacent intermediate parts 26 are further secured to each other.

[0093] According to the first embodiment, presented above, the first part 22, second part 24 and intermediate part 26 are secured to each other by laser welding. A laser beam is pointed at the covered portion 30 through the covering portion 32. This generates heating of said portions 30, 32, resulting in welding of the parts comprising said portions 30, 32.

[0094] According to the second embodiment, the first part 22, second part 24 and intermediate part 26 are secured to each other by edge-to-edge welding. The adjacent edges 60 of two parts are affixed on either side of the resistive sheet 58. A current is then generated through the resistive sheet 58 for its heating by Joule effect. The adjacent edges 60 are thus heated, resulting in welding of the adjacent edges 60 to the resistive sheet 58.

[0095] According to the third embodiment, presented above, the first part 22, second part 24 and intermediate part 26 are secured to each other by hot gas welding.

[0096] The heating of adjacent parts for their local fusion and for the resulting weld is then carried out by means of a jet of hot gas.

[0097] It will be understood that the different welding methods presented in the three embodiments above can be combined and are for example interchangeable. For example, the first part 22 is secured to one of the intermediate parts 26 by laser welding, the second part 24 is secured to another of the intermediate parts 26 by laser welding, the intermediate parts 26 being welded together by edge-to-edge welding.

Claims

Claims

1. Pressurized gas containment envelope (12), comprising: - a first part (22), comprising a first shell (44), - a second part (24), comprising a second shell (52), - at least one intermediate part (26), arranged between the first (22) and the second part (24), in an assembly direction (A-A'), the intermediate part(s) (26) being secured to the first (22) and second parts (24), the first part (22), the second part (24) and the at least one intermediate part (26) together delimiting an interior volume (28), the or at least one of the intermediate part(s) (26) comprising: - an intermediate shell (34), and - at least one pillar (36) elongated in an elongation direction (E-E'), connecting two opposite portions of the intermediate shell (34) and passing through the interior volume (28) perpendicular to the assembly direction (A-A'),the pillar (36) and the intermediate shell (34) being made of one material, characterized in that the envelope (12) comprises a plurality of intermediate parts (26), adjacent in the assembly direction (A-A').,

2. An envelope (12) according to claim 1, wherein the at least one intermediate portion (12) comprises a plurality of pillars (36), the plurality of pillars (36) being aligned in a direction perpendicular to the assembly direction (A-A') and to the elongation direction (E-E') of said pillars (36).

3. Envelope (12) according to claim 1 or 2, in which the at least one pillar (36) is hollow, the pillar (36) comprising a pillar wall (38), connected to the intermediate shell (34) and delimiting a pillar cavity (40), the pillar (36) and the intermediate shell (34) delimiting two openings (42) so that the pillar cavity (40) opens on either side of the intermediate part (26).

4. An envelope (12) according to any preceding claim, wherein: - the first part (22) comprises at least one first reinforcing rib (46) secured to the first shell (44), said first reinforcing rib (46) comprising a slot (50) extending parallel to the direction of elongation (E-E') and opening out on either side of the first part (22), and / or - the second part (24) comprises at least one second reinforcing rib (54) secured to the second shell (52), said second reinforcing rib (54) comprising a slot (56) extending parallel to the direction of elongation (E-E') and opening out on either side of the second part (24).

5. Envelope (12) according to any one of the preceding claims, in which the first part (22), the at least one intermediate part (26) and the second part (24), are alternately in the assembly direction (A-A'), formed from a material configured to be transparent to laser radiation and from a material configured to absorb the laser radiation, the first part (22), the at least one intermediate part (26) and the second part (24), being secured to each other in the assembly direction (A-A') by laser welding.

6. Envelope (12) according to any one of claims 1 to 4, in which the first part (22), the at least one intermediate part (26) and the second part (24), are secured to each other in the assembly direction (A-A') by edge-to-edge welding, a resistive sheet (58) being arranged between adjacent welded edges (60) of the first part (22), of the at least one intermediate part (26) or of the second part (24).

7. Envelope (12) according to claim 6, in which the adjacent welded edges (60) delimit between them an oblique edge-to-edge welding plane (S), extending obliquely relative to the assembly direction (A-A').

8. A pressurized gas tank (10) comprising a pressurized gas jacket (12) according to any one of claims 1 to 7, and a tank body (14) disposed around the jacket (12), an inner face (18) of the tank body (14) being affixed to an outer face (20) of the envelope (12).

9. A method of manufacturing a pressurized gas containment envelope (12), comprising the following steps: - providing a first part (22), a second part (24) and at least one intermediate part (26) of the envelope (12); - joining the intermediate part(s) (26) to the first (22) and second (24) parts, the intermediate part(s) (26) being arranged between the first part (22) and the second part (24) in the assembly direction (A-A'), characterized in that the envelope (12) comprises a plurality of intermediate parts (26), adjacent along the assembly direction (A-A').

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