EP3821166A1

EP3821166A1 - Hydrogen storage tank comprising a plurality of umbrella-like divider elements

Info

Publication number: EP3821166A1
Application number: EP19769841.8A
Authority: EP
Inventors: Olivier Gillia; Albin Chaise
Original assignee: Commissariat a lEnergie Atomique CEA; Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
Current assignee: Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
Priority date: 2018-08-10
Filing date: 2019-08-07
Publication date: 2021-05-19
Also published as: FR3084924B1; WO2020030878A1; FR3084924A1

Abstract

The invention mainly concerns a hydrogen storage tank (1), comprising: a shell (3) of longitudinal axis (X); a central pole (4); and a stack of a plurality of divider elements (5). Each divider element (5) forms, with the central pole (4), an umbrella-like folding structure, comprising a plurality of ribs to which a membrane supporting the storage material (2) is attached.

Description

HYDROGEN STORAGE TANK HAVING A PLURALITY OF ELEMENTS

UMBRELLA-TYPE SEPARATION

DESCRIPTION

TECHNICAL AREA

The present invention relates to the general field of hydrogen storage tanks in the form of hydrides, in particular metal hydrides.

Hydrogen belongs to the storable vectors of alternative energies which have been developed for several years now. Hydrogen can be obtained in various ways, for example from natural gas or other hydrocarbons, and can in particular be produced by means of the electrolysis of water at high temperature (EHT), in particular the high temperature water vapor electrolysis (EVHT), respectively designated by the English names "High Temperature Electrolysis" (HTE) and "High Temperature Steam Electrolysis" (HTSE). Hydrogen can also advantageously be used as an energy source in solid oxide fuel cells, usually designated by the acronym SOFC for "Solid Oxide Fuel Cells" in English or in fuel cells with proton exchange membranes. (or PEMFC for “Proton Exchange Membrane Fuel Cells” in English).

The invention finds applications in various fields of industry, and in particular when there is a need for hydrogen compression, such as for example hydrogen gas compressors by hydrides such as for hydrogen service stations. In addition, the invention applies both to hydrogen storage solutions of stationary type and of on-board type. In addition, the invention is also suitable for devices requiring the administration of a swelling of an absorbent material to another compound, such as for storing ammonia (NH ₃₎ in AdAmmine ^® of the company Amminex .

Thus, the invention can be used for on-board storage of hydrogen, for example for a fuel cell or heat engine, for example for the means transportation, such as boats, submarines, cars, buses, trucks, construction equipment, two wheels, among others.

In addition, the invention can be used in the field of transportable power supplies such as batteries for portable electronic devices such as portable telephones, portable computers, among others.

The invention can also be used for the stationary storage of hydrogen, for example in large quantity, as for generator sets, or for the storage of hydrogen produced in large quantity by electrolysis of water with electricity from wind turbines, photovoltaic panels, geothermal energy, among others.

Finally, the invention can also make it possible to store any other source of hydrogen originating for example from the reforming of hydrocarbons or from other processes for obtaining hydrogen (photo-catalysis, biological, geological, among others).

Thus, the invention provides a hydrogen storage tank by absorption of hydrogen in a hydrogen storage material comprising a plurality of separating elements in the form of folding structures of the umbrella type, as well as a method associated manufacturing.

PRIOR STATE OF THE ART

The storage of hydrogen in a hydride is an exothermic reaction, namely that it gives off heat, while the release of hydrogen is an endothermic reaction, namely that it absorbs heat.

An important constraint in the field of hydrogen storage and release is to be able to best manage the thermal operating regimes of the hydride-based tank. It is for example interesting to couple this thermal to that of a solid oxide fuel cell (SOFC) or a fuel cell with proton exchange membrane (PEMFC).

Thus, in order to be able to manage the endothermic, respectively exothermic, aspects of the desorption of hydrogen from the hydride reservoir, respectively of the absorption of hydrogen, the prior art conventionally teaches to design a hydride tank which consists of an envelope, a hydride, and sometimes internal tubes, with or without fins, which bring calories or frigories directly into the tank.

The envelope is responsible for confining the hydrogen gas part. This envelope must hold the pressure necessary for the proper functioning of the hydride, and therefore withstand the maximum pressure that can develop in the tank. It is therefore conventionally a gas tank, which can also be called an envelope, a bottle, a container of hydrogen gas, packaging, a pressure enclosure, among others.

The hydride can be arranged in different ways in the envelope. The hydride has the property of absorbing (or adsorbing) and desorbing the hydrogen, so as to obtain a more compact storage thereof. Hydride management is accompanied by thermal management, but also mechanical management, because the hydriding phenomenon is accompanied by a swelling phenomenon of the material. Hydride is therefore rarely introduced alone into the envelope under pressure, and is often accompanied by a structure allowing thermomechanical management of the sorption phenomenon.

In order to best hold the hydrogen pressure inside the tank, certain designs involve tanks in the form of vertical cylinders.

However, in order to best manage the mechanical stresses applied to the hydride reservoir, it is well known to adopt a stepped design of such a vertical cylinder in order to avoid having an excessively deep hydride bed. In other words, many designs of hydride reservoirs in the form of vertical cylinders provide for the placement of multiple partitions in the cylinder to form a plurality of hydride beds spaced vertically therebetween.

In fact, the technical solutions which do not set up these separations and which only provide for one hydride bed at the bottom of the vertical cylinder are not viable from a mechanical point of view. The phenomenon of “breathing” of hydrides during absorption and desorption of hydrogen, namely swelling and deflation of hydrides which can reach 30% on certain hydrides, causes the appearance of strong stresses on the walls of the cylinder also called cylinder shell. As described in the article "Stress on a reaction vessel by the swelling of a hydrogen absorbing alloy ”, K. Nasako et al, January 1998, Journal of Alloys and Compounds, Volume 264, pages 271-276, these constraints increase with the number of absorption / desorption cycles until reaching the limit elasticity of the material, which is unacceptable for a hydrogen storage tank. Empirically, it is preferable that the depth of the hydride bed is less than the diameter of this bed.

Various solutions of hydride reservoirs in the form of vertical cylinders with the establishment of multiple partitions have therefore been described in the prior art.

By way of example, French patent application FR 2 953 820 A1 discloses the use of vertical separators in the form of cups, placed at equal distance by threading them on a porous hydrogen distribution tube at the same time as in the cylinder shell. A curved edge makes it possible to create flexibility which makes it possible to put in elastic clamping the cups on the tube or the ferrule. The device ensures easy passage of hydrogen to or from the hydride powder by ensuring confinement of the hydride powder in each well.

Furthermore, French patent application FR 2 996 628 A1 describes a compartmentalization of a hydride tank in the form of a vertical cylinder produced by means of buckets stacked on a central tube. The central tube is made up of an assembly of tube sections, each section being mounted clamped in a central orifice of each cup. The seal between each cup is ensured by deformation of the lips. Hydrogen arrives in each well because the central tube is porous to hydrogen but not to hydride powder. Here again, the device makes it possible to ensure easy passage of the hydrogen to or from the hydride powder by ensuring confinement of the hydride powder in each well.

In addition, French patent application FR 3 014 999 A1 teaches the production of compartmentalization by means of stacked buckets. The hydrogen enters through a filter incorporated in the walls of the cup, and a sealing by fitting and O-ring is carried out between each of the cups. Thus, various solutions for the design of hydride reservoirs in the form of vertical cylinders with separating elements have already been envisaged by the prior art based on the principle that, in order to limit the mechanical stresses, a single bed of deep hydrous hydride powder on the bottom of the tank was not viable.

In addition, the article "A study on wall stresses induced by LaNis alloy hydrogen absorption-desorption cycles", BY Ao et al, March 22, 2005, Journal of Alloys and Compounds, Volume 390, pages 122-126, the article " Effects of cyclic hydriding-dehydriding reactions of LaNis on the thin-wall deformation of metal hydride storage vessels with various configuration ”, CK. Ling et al, June 29, 2012, Rewable Energy, Volume 48, pages 404-410, and the article "A tool for modeling the breathing of hybride powder in its container while cyclically absorbing and desorbing hydrogen", B. Charlas et al, January 8, 2015, International Journal of Hydrogen Energy, Volume 40, pages 2283-2294, demonstrated that, to limit the mechanical stresses, it is necessary to limit the depth of the hydride powder bed. In particular, for a ratio between depth of the hydride powder bed and width of the hydride powder bed less than 1, the mechanical stresses remain low.

There also remains a need to improve the design of hydride reservoirs in the form of vertical cylinders, in particular involving the vertical separation of the hydride powder bed into a plurality of shallow hydride beds.

STATEMENT OF THE INVENTION

The object of the invention is to at least partially remedy the needs mentioned above and the drawbacks relating to the embodiments of the prior art.

The invention aims in particular to propose a new design of hydrogen storage tank, in particular hydride tank in the form of a vertical cylinder, which is simple and practical so as to make assembly easy.

According to one of its aspects, the subject of the invention is therefore a hydrogen storage tank by absorption of hydrogen in a hydrogen storage material comprising: - an envelope with a longitudinal axis closed at its two longitudinal ends,

- a central mast extending along the longitudinal axis,

a stack of a plurality of separation elements along the longitudinal axis, each separation element having a passage allowing the mounting of the separation element around the central mast, and each separation element forming a substantially bottom perpendicular to the longitudinal axis adapted to receive a hydrogen storage material so as to form a plurality of beds of hydrogen storage material.

Advantageously, the storage tank comprises a hydrogen storage material.

Preferably, each separating element forms with the central mast an umbrella-type folding structure, each separating element comprising a plurality of ribs fixed to the central mast and on which is fixed a membrane for supporting the storage material, the largest of which transverse dimension is greater than the largest transverse dimension of the internal volume of the envelope in which the central mast, the separating elements and the hydrogen storage materials are located.

The support membrane (s) can, if necessary, play the role of heat conduction fins.

Advantageously, the support membrane or membranes are impermeable to grains of hydrides.

In addition, more preferably still, each separating element comprises a strip for plating the support membrane against the inner wall of the envelope, the strip for plating extending around the entire periphery of the support membrane, being able to come in contact with the envelope.

Also advantageously, each separation element further comprises a plurality of forks and a sliding piece (or sliding), each fork being fixed to a whale and to the sliding piece mounted in slide connection or pivot sliding around the central pole so as to allow the deployment of the umbrella. These forks can for example take the form of rods and / or cords.

The hydrogen storage tank according to the invention may also include one or more of the following characteristics taken in isolation or according to any possible technical combination.

Preferably, the separation elements are regularly spaced from each other along the central mast.

Also preferably, the envelope is of cylindrical shape. In addition, the longitudinal axis of the envelope preferably corresponds to a vertical axis so that the envelope is preferably in the form of a vertical cylinder.

Each separating element can comprise a locking element in the open position of the deployed umbrella, the locking element being positioned in contact with the sliding part so that the sliding part is located between the locking element and the support membrane.

The envelope is preferably a bottle, in particular of gas, comprising an inlet orifice in the form of a neck of larger transverse dimension less than half of the largest transverse dimension of the internal volume of the envelope.

Advantageously, the invention can thus allow the creation of substantially horizontal partitions, filled with hydrides, in a gas cylinder provided with a narrow neck, unlike the embodiments of the prior art. More specifically, the invention can make it possible to insert, at the top of a bottle with a narrowed neck, a central mast on which are arranged n folding structures forming n bottoms creating n vertical partitions of low slenderness. These bottoms can then come into contact with the interior of the bottle and be supported by the forks in connection with the central mast, only the weight of the hydrides allowing in particular the plating of the support membrane on the interior of the bottle.

Each whale can be fixed to the central mast by means of a ligating element securing a portion of the whale to the central mast, the whale having a pivot link to allow its deployment and / or retraction relative to the mast central. This pivot link can for example be a pivot link with clevis mounting.

The whales are advantageously mounted on the central mast in a sealed manner. The whales can particularly be mounted tight on the central mast, being in particular fixed by means of ligating elements as described above, for example by soldering, by welding, by gluing, among others.

In addition, the distance, or even the longitudinal space, between two successive separation elements along the longitudinal axis can be less than the largest transverse dimension of the internal volume of the envelope.

In this way, it is possible to obtain beds of storage materials which are not too long longitudinally, in particular vertically. In other words, the thickness of the storage material beds can be controlled.

Thus, the ratio between the distance between two successive separation elements and the largest transverse dimension of the internal volume of the envelope can be strictly less than 1. This value can be refined by carrying out in particular stress increase measures for beds of storage materials of different slenderness, in particular the fact that each storage material, in particular each hydride, does not exhibit the same behavior in cycling.

Furthermore, the central mast can form a hydrogen supply and collection conduit comprises a plurality of hydrogen passage orifices, for example produced by drilling, in particular at least one hydrogen passage orifice on each stage of the tank formed between two successive separation elements.

In addition, the mast in the form of a hydrogen supply and collection conduit can advantageously comprise a plurality of filters arranged against the conduit, each filter being opposite at least one orifice for the passage of hydrogen, the conduit comprising in particular at least one filter disposed against at least one hydrogen passage orifice formed on the mast on each stage of the tank formed between two successive separation elements. Advantageously, the presence of a filter covering at least one hydrogen passage orifice makes it possible to prevent the storage material, in particular in the form of hydride powder, from being able to escape through the mast.

The filters may for example include a fabric or a fine mesh felt. The filters can also comprise a metallic and / or polymeric material, or even any other type of material. The filters can then be wrapped around the mast. In order to obtain a good seal, more than one winding of the filter in the form of fabric or felt around the mast can be carried out.

Furthermore, each filter can be held against the mast by means of clamping means, in particular clamps. Such clamps can for example correspond to clamps of the Serflex or Colson type.

In addition, the hydrogen storage material may preferably comprise hydrides, in particular metal hydrides.

Furthermore, the subject of the invention is also, according to another of its aspects, a process for manufacturing a hydrogen storage tank as defined above, characterized in that it comprises, for each stage of the tank, storage formed by a separating element secured to the central mast, the following successive steps:

insertion of the separation element through an inlet opening of the envelope, the separation element being in the non-deployed form of the umbrella when it passes through the entry opening,

- deployment of the umbrella of the separation element once located inside the envelope,

- Placement of hydrogen storage material on the separation element before insertion of any additional separation element, and in that it further comprises the step, after insertion of all the separation elements in the envelope, closing the inlet opening of the envelope.

The hydrogen storage tank and the manufacturing method according to the invention may include any of the characteristics set out in the description, taken in isolation or in any technically possible combination with other characteristics.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood on reading the detailed description which follows, of non-limiting examples of implementation thereof, as well as on examining the figures, schematic and partial, of the appended drawing, on which :

FIGS. 1, 2 and 3 are schematic sectional views illustrating three stages of filling hydrogen storage material with an exemplary embodiment of a hydrogen storage tank according to the invention,

FIG. 4 is an enlarged and diagrammatic view of FIGS. 1, 2 and 3, making it possible to better visualize the stages of the hydrogen storage tank,

FIG. 5 is a bottom view of a stage of the hydrogen storage tank,

FIG. 6 is a schematic perspective view showing the central mast in isolation in the form of a supply and collection pipe for hydrogen from the hydrogen storage tank, and

- Figure 7 shows, in a partial section, a detail of the attachment between a whale and the central mast of a hydrogen storage tank according to the invention.

Throughout these figures, identical references may designate identical or analogous elements.

In addition, the different parts shown in the figures are not necessarily shown on a uniform scale, to make the figures more readable.

DETAILED PRESENTATION OF PARTICULAR EMBODIMENTS

It is specified that, in the description which follows of particular embodiments of the invention, the hydrogen storage material corresponds to hydrides, in particular metal hydrides, in particular in the form of powders. In addition, the hydrogen storage tank described has a cylindrical shape of revolution. However, any reservoir formed by hollow element having a longitudinal dimension greater than its transverse dimension, and having any cross section, for example circular or polygonal or ellipsoidal, does not depart from the scope of the present invention.

In order to facilitate the introduction of hydrides into the stages of the tank 1, they can be manufactured in the form of aggregates with good flowability. It should be noted that an activated hydride, that is to say having undergone a few cycles of absorption and desorption of hydrogen, is automatically transformed into powder, namely that it "decrepit", whose particle size depends on its nature, but is typically of the order of a few microns.

It should also be noted that, in the embodiments described below, the filters 11 used correspond to felts made of polymer material and the clamps 12 are of the Colson type. Of course, these choices are in no way limiting.

Referring to Figures 1 to 3, there is schematically illustrated in section three stages of filling with hydrogen storage material 2 of an exemplary embodiment of a hydrogen storage tank 1 according to the invention. In addition, Figure 4 is an enlarged and schematic view of Figures 1, 2 and 3, and Figure 5 is a bottom view of a stage of the hydrogen storage tank 1.

The reservoir 1 comprises an envelope, or ferrule 3, of longitudinal axis X closed at a lower end by a lower bottom 14. The reservoir 1 also comprises an inlet orifice 13 intended to be closed after the central mast 4 has been put in place and separating elements 5 to close the upper end of the shell 3.

The inner wall Pi of the shell 3 makes it possible to hold the hydrogen pressure. It is also the wall on which the mechanical pressure of the hydrides is exerted. This pressure is considered negligible if the thickness of the hydride bed is small compared to its diameter, and if the hydrides have sufficient space to breathe.

The reservoir 1 is intended to be generally oriented so that the longitudinal axis X is substantially aligned with the direction of the gravity vector. However, during its use, for example in the case of on-board use, its orientation may change.

The reservoir 1 comprises a central mast 4 extending along the longitudinal axis X from the bottom bottom 14 towards the inlet orifice 13.

As will be explained below, the interior of the tank 1 is divided into a plurality of stages along the longitudinal axis X and each stage comprises storage material 2. These stages are produced in such a way that they prevent the passage of the storage material, in particular in the form of hydride powder, from one stage to another, thus preventing the accumulation of powder in a stage, in particular in the lower stages and the appearance of pressure stresses on the inner wall of the shell 3.

Thus, the tank 1 comprises a stack of a plurality of separation elements 5 along the longitudinal axis X, regularly spaced from one another along the mast 4. These separation elements 5 are mounted on the mast 4 tightly, for example by brazing, welding, gluing or force fitting, or even being formed in one piece with the mast 4. In addition, these separating elements 5 are here in the form of discs once deployed.

Each separating element 5 has a passage 6, or central orifice, which allows it to be mounted around the mast 4. In addition, each separating element 5 defines a bottom substantially perpendicular to the longitudinal axis X on which hydride powder is deposited during the manufacture of the reservoir 1 to form a plurality of stages or hydride powder beds.

The separation elements 5 are located on the mast 4 so that the longitudinal space EL between two successive separation elements 5 is less than the internal diameter Tv of the internal volume V of the shell 3. Thus, the thickness of the powder beds hydride can be controlled. In other words, the EL / Tv ratio is strictly less than 1.

Advantageously, each separating element 5 forms with the central mast 4 a folding structure of the umbrella type. More specifically, as best seen in Figures 4 and 5, each separating element 5 comprises a plurality of ribs 7 fixed to the central mast 4 and on which is fixed a support membrane 8 of the storage material 2. Each whale 7 constitutes a support piece for the floor where it appears.

The support membrane 8 is advantageously flexible and supports the storage material 2. The support membrane 8 can be permeable to hydrogen. However, it remains impermeable to hydride grains so as not to have transfer of hydrides to the lower stages, mainly due to gravity.

The largest transverse dimension Tm of the support membrane 8 is greater than the largest transverse dimension Tv of the internal volume V of the casing 3 in which the central mast 4, the separation elements 5 and the storage materials 2 are located hydrogen. In this way, a seal can be produced against the interior wall Pi of the envelope 3.

More precisely, each separating element 5 comprising a plating whale 9 of the support membrane 8 against the inner wall Pi of the envelope 3. This plating whale 9 extends over the entire periphery of the support membrane 8, and comes into contact with the envelope 3 at the end of the deployment of the umbrella. In this way, it is possible to seal the storage material 2 between the different stages.

Advantageously, the plating whale 9 is deformable. When the umbrella is in the folded position, the tacking whale 9 forms a loop. On the other hand, when the umbrella is in the unfolded position, the tacking whale 9 forms an arc of circle which presses the support membrane 8 against the inner wall Pi of the envelope 3. The tacking whale 9 thus forms a circumferential whale which ensures circumferential contact of the support membrane 8 on the shell 3.

In addition, each separating element 5 comprises a plurality of forks 10, also called strut whales, and a sliding part 11. Each fork 10 is fixed to a whale 7 and to the sliding part 11 mounted in sliding or pivoting link connection around the central mast 4 so as to allow the deployment of the umbrella. Each fork 10 makes it possible to exert a force on a corresponding whale 7 so that the latter can press the support membrane 8 against the inner wall Pi of the envelope 3.

The sliding part 11 forms a part in sliding or pivoting connection with the axis 4 which enables the deployment of the umbrella.

It should also be noted that each separation element 5 comprises a locking element 12 to maintain the structure 5 of the umbrella in the deployed position. This locking element 12 blocks the ascent of the sliding part 11 by pressing on the axis 4. In FIG. 4, this part 12 is in a groove machined in the axis 4. The sliding part 11 is located between the locking element 12 and the support membrane 8.

The principle of obtaining the reservoir 1 is for example as described below. Several separating elements 5 are inserted through the inlet orifice 13 of the casing 3, in particular through a narrow neck of a gas cylinder, each separating element 5 being in the non-deployed form of the umbrella when its passage through the inlet orifice 13, that is to say that the sliding parts 11 are raised to the maximum.

Once inside the envelope 3, the umbrella is deployed, by pushing down on the sliding part 11 then placing the blocking element 12 to force the umbrella into the open position plated on the inside of the envelope 3. The storage material 2 is put in place, for example by means of a funnel 15 causing the storage material 2 to flow along the central mast 4, through the inlet orifice 13 , to reach the support membrane 8. The dosage is done by weighing. The quantity to be introduced is calculated according to the experience of the designer and the storage material used.

The filling of one stage of the tank 1 is done one by one, so that the placement of storage material 2 on a separation element 5 is done before insertion of any other additional separation element 5. After insertion of all the separation elements 5 in the casing 3, as in FIG. 3, the central mast 4 comes into abutment on the bottom 14 and the inlet orifice 13 of the casing 3 can be closed, by example by a plug inserted in the neck.

The plug can be drilled, allowing hydrogen to pass in and out. This plug is generally fitted with a valve and a device for protection against overpressure (valve, rupture disc with pressure or temperature triggering, among others).

Preferably, the inlet orifice 13 of the casing 3 corresponds to a narrow neck of a gas cylinder, the diameter Dg of which is clearly less than half the internal diameter Tv of the internal volume V of the casing 3.

Thus, the invention implements the insertion, through the narrow neck of a gas cylinder, of a central mast 4 provided with separation elements 5 allowing the installation of several staged compartments of small thickness in which a controlled quantity of storage material 2 is poured step by step, bringing the assembly under construction down one stage at each stage.

Advantageously, the envelope 3 is of cylindrical shape of revolution with a vertical axis X. In the figures shown, the two ends of the envelope 3 are spherical bottoms, the spherical shape being an effective shape for bottles having to contain a pressurized gas, in this case hydrogen. However, other types of shape are possible for the bottoms of the envelope 3, for example curved bottoms, flat bottoms, among others.

The dimensioning of the casing 3 is for example made according to standard ISO 16111, when it applies, depending on the use and the size of the tank produced, or according to the European regulations for pressure vessels, ie the Directive No. 97/23 / EC of May 29, 1997. The invention could thus be profitable when bottles whose ends must be welded before introduction of the hydrides inside are used. This is the case for example of the conventional bottles used by gas manufacturers to deliver these gases to their customers, such as in particular the bottle known under the name B50, that is to say with a capacity of 50 liters in water equivalent. In the case of the manufacture of this kind of bottles, one cannot introduce hydrides inside before they are finished and certified. In fact, these bottles are manufactured by welding several parts together, the upper rounded bottom of which closes the bottle welded to the ferrule part of the bottle. At the end of the welding, the bottles undergo a heat treatment at high temperature, then a pressure test of incompressible liquid (mostly water) in order to check their mechanical strength. These last two operations: heat treatment and pressure test, are absolutely not compatible with the presence of hydrides inside the bottle. Hydrides must therefore be introduced subsequently into the bottles.

Thus, one of the advantages of the invention is to take advantage of common manufacturing methods, well controlled and optimized, to manufacture the pressure envelopes of hydride tanks. To use these envelopes or bottles, or packaging, to constitute the envelope holding the gas pressure of a hydride tank, it is necessary to manage to insert hydrides in the bottles with the narrow neck, and this in a suitable manner, that is to say ie in a layered manner as presented previously. It is therefore necessary to bring the staging structure into the bottle which already incorporates these ends which close the main cylinder.

In certain embodiments of the invention, the central mast 4 also forms a hydrogen supply and collection conduit.

Thus, as visible in FIG. 6, the mast 4 advantageously comprises a plurality of orifices 20, or holes 20, for the passage of hydrogen, for example produced by drilling. More precisely, each stage of the tank 1 has a plurality of orifices 20 at the level of the mast 4.

The mast 4 then advantageously comprises a filter 21 at each level to cover the orifices 20 with hydrogen passage.

These filters 21 make it possible to prevent the hydride powder 2 from escaping through the mast 4 in the form of a conduit. They can for example be made of fabric or fine mesh felt, for example comprising a material metallic and / or polymer. In order to obtain a good seal, the filters in this form are wound more than once around the mast 4.

Furthermore, in order to allow the filters 21 to be held on the mast 4 once the winding is finished, clamps 22 can be used, as visible in FIG. 3, for example of the Colson type.

FIG. 7 also represents, in a partial section, a detail of embodiment of the attachment between a whale 7 and the central mast 4.

Thus, as can be seen in this FIG. 7, each whale 7 is fixed to the central mast 4 by means of a ligating element 25 which allows the joining of a portion of the whale 7 to the central mast 4.

In addition, each whale 7 has a pivot link 26, produced for example by means of a deformable link, to allow its deployment and / or retraction relative to the central mast 4.

The principle of the invention therefore thus implements a plurality of mechanical connections between the different parts described above. More specifically, the connection between a whale 7 and the central mast 4 is a pivot connection with an orthoradial direction axis relative to the central mast 4. The connection between a whale 7 and a fork 10 is a pivot connection with a direction axis orthoradial. The connection between a fork 10 and the sliding piece 11 is a pivot connection with an axis of orthoradial direction. The connection between the central mast 4 and the sliding part 11 is a sliding pivot connection with an axis of vertical direction. The connection between a whale 7 and the envelope 3 is a point connection. The connection between a whale 7 and the tacking whale 9 is a ball joint. Finally, the connection between the central mast 4 and the locking element 12 is a complete connection. For all the pivot connections envisaged in the present invention, multiple possibilities exist, well known to those skilled in the art. By way of example, one or more of the pivot connections described above can be pivot connections with clevis mounting.

The use of the reservoir 1 according to the invention in storage mode is done by admitting hydrogen at a pressure capable of activating the absorption of hydrogen in the storage material 2, that is to say at a pressure higher than the pressure of hydride balance. Hydrogen is supplied to the hydride, either by the central mast 4 and distribution holes 20 through each stage, or by percolation through the various hydride beds and the support membranes 8 which are then permeable to the hydrogen, but not to powder, being for example a metallic or polymeric fabric with a very fine mesh.

During the loading, the hydride will release heat, which can be easily evacuated through the wall of the envelope 3. To gain in efficiency of heat exchange, and therefore in speed of filling of the tank 1, it is advantageously possible to cool this wall with a heat transfer fluid.

For the tank purge phase 1, the hydrogen leaves the storage material 2 if a sufficiently low pressure is applied at the outlet of the tank 1 compared to the equilibrium pressure of the hydride. The hydrogen then exits either through the central mast 4, or by percolation through the stages of hydride and of support membranes 8, which in this case are porous with hydrogen. It is possible to facilitate this desorption by providing heat through the wall of the envelope 3 by heating, for example using a heat transfer fluid or from any other source such as an electrical heating resistance.

It should be noted that, due to the constructive arrangement adopted - the cavities in which the hydride is found have a rather flat aspect ratio, that is to say with a height smaller than the width -, the operation of the reservoir 1 is carried out in a substantially vertical manner, the vertical being defined as the direction of earth's gravity. In a horizontal position, the desired ratio would be reversed - the cavity would be deeper than wide -, and greater mechanical stresses would develop following the swelling of the hydride. The vertical position also has the advantage that the actual weight of the hydride contributes to pressing the separating elements 5 against the internal wall Pi of the casing 3.

Furthermore, it is possible to form a locking element 12 in the open position of the deployed umbrella which is more elaborate than a sliding element on the central mast 4 coming into contact with the sliding part 11. By way of examples, the locking element 12 can be formed by an unlockable ratchet system to make it possible to dismantle the separation elements 5, for example to change the storage material 2 which would have reached the end of its life. . Indeed, the storage material 2, for example a hydride, can wear out, prematurely or not, for example following a pollution of the hydrogen by components detrimental to its functioning such as carbon monoxide (CO ), water (H ₂ 0), dioxygen (0 ₂ ), among others, or to the natural decrease in the storage capacity of the hydride by demixing phenomenon for example.

Of course, the invention is not limited to the exemplary embodiments which have just been described. Various modifications can be made by those skilled in the art.

Claims

1. Hydrogen storage tank (1) by absorption of hydrogen in a hydrogen storage material (2) comprising:

- a hydrogen storage material (2), comprising hydrides,

- a casing (3) with a longitudinal axis (X) closed at its two longitudinal ends,

- a central mast (4) extending along the longitudinal axis (X),

- a stack of a plurality of separation elements (5) along the longitudinal axis (X), each separation element (5) having a passage (6) allowing the mounting of the separation element (5 ) around the central mast (4), and each separation element (5) forming a bottom substantially perpendicular to the longitudinal axis (X) capable of receiving said hydrogen storage material (2) so as to form a plurality of hydrogen storage material (2) beds,

characterized in that each separating element (5) forms with the central mast (4) an umbrella-type folding structure, each separating element (5) comprising a plurality of ribs (7) fixed to the central mast (4) and on which is fixed a support membrane (8) of the storage material (2), impermeable to hydride grains, the largest transverse dimension (Tm) of which is greater than the largest transverse dimension (Tv) of the internal volume (V ) of the envelope (3) in which the central mast (4), the separation elements (5) and the hydrogen storage materials (2) are located.

2. Reservoir according to claim 1, characterized in that each separation element (5) comprises a plating rib (9) of the support membrane (8) against the internal wall (Pi) of the envelope (3), the plating rib (9) extending over the entire periphery of the support membrane (8), being capable of coming into contact with the envelope (3).

3. Tank according to claim 1 or 2, characterized in that each separation element (5) further comprises a plurality of forks (10) and a sliding part (11), each fork (10) being fixed to a whale (7) and to the sliding part (11) mounted in sliding or pivot connection sliding around the central mast (4) so as to allow the deployment of the umbrella.

4. Tank according to claim 3, characterized in that each separation element (5) comprises a locking element (12) in the open position of the deployed umbrella, the locking element (12) being positioned in contact with the sliding part (11) so that the sliding part (11) is located between the locking element (12) and the support membrane (8).

5. Tank according to any one of the preceding claims, characterized in that the envelope (3) is a bottle, in particular of gas, comprising an inlet orifice (13) in the form of a larger neck transverse (Dg) less than half of the largest transverse dimension (Tv) of the internal volume (V) of the envelope (3).

6. Tank according to any one of the preceding claims, characterized in that each whale (7) is fixed to the central mast (4) by means of a ligating element (25) securing a portion of the whale (7) to the central mast (4), the whale (7) comprising a pivot link (26) to allow its deployment and / or retraction relative to the central mast (4).

7. Tank according to any one of the preceding claims, characterized in that the distance (EL) between two successive separation elements (5) along the longitudinal axis (X) is less than the largest transverse dimension (Tv ) of the internal volume (V) of the envelope (3).

8. Tank according to any one of the preceding claims, characterized in that the central mast (4) forms a hydrogen supply and collection conduit comprises a plurality of orifices (20) for the passage of hydrogen, in particular at at least one orifice (20) for the passage of hydrogen on each stage of the tank (1) formed between two successive separation elements (5).

9. Tank according to claim 8, characterized in that the mast (4) in the form of a hydrogen supply and collection conduit comprises a plurality of filters (21) disposed against the mast (4), each filter (21) being opposite at least one orifice (20) for hydrogen passage, the mast (4) comprising in particular at least one filter (21) disposed against at least one orifice (20) for hydrogen passage formed on the mast (4) on each stage of the tank (1) formed between two successive separation elements (5).

10. Tank according to claim 9, characterized in that each filter (21) is held against the mast (4) by means of clamping means (22), in particular clamps (22).

11. Tank according to any one of the preceding claims, characterized in that the hydrogen storage material (2) comprises metal hydrides.

12. A method of manufacturing a hydrogen storage tank (1) according to any one of the preceding claims, characterized in that it comprises, for each stage of the storage tank (1) formed by a separating element (5) secured to the central mast (4), the following successive steps:

- insertion of the separation element (5) through an inlet orifice (13) of the envelope (3), the separation element (5) being in the non-deployed form of the umbrella during its passage through the inlet orifice (13),

- deployment of the umbrella of the separation element (5) once located inside the envelope (3), - placement of hydrogen storage material (2) on the separation element (5) before insertion of any additional separation element (5),

and in that it further comprises the step, after insertion of all the separating elements (5) in the envelope (3), of closing the inlet orifice (13) of the envelope (3 ).