Electric distribution plate and electrolyser stack therefor

Abstract

Electrical distribution plate for an electrolyser stack, the plate comprising two main faces, the first face (21) being intended to face towards a block of electrolytic cells of the electrolyser stack and the second face (22) being intended to face towards a bottom plate of the electrolyser stack, the plate comprising at least one recess (24) formed on the second main face, the plate further comprising at least one orifice passing through the plate so as to open at a first end onto the first face and open at a second end onto the second face, the orifice opening at its second end: at the recess, and / or outside the recess, the distribution plate then comprising at least one groove opening into the orifice on the one hand and into the recess on the other hand. Corresponding electrolyser stack.

Description

[0001] ELECTRICAL DISTRIBUTION PLATE AND ASSOCIATED ELECTROLYSER CELL

[0002] DESCRIPTION

[0003] The invention relates to an electrical distribution plate.

[0004] The invention also relates to an electrolyzer stack comprising such an electrical distribution plate.

[0005] BACKGROUND OF THE INVENTION

[0006] The overall architecture of an electrolyzer stack (generally referred to as an "electrolyzer stack") usually consists of a block of electrolytic cells, which are stacked in series from an electrical point of view and in parallel from a fluidic point of view, and seals.

[0007] Each electrolytic cell aims to promote 1 1electrolysis of an electrolytic solution (alkaline water, pure water, unpurified water, salt, aqueous chloride solution, aqueous bromide solution, aqueous hydrochloric acid solution, etc.). For example, the functionality of an electrolyzer cell is to promote the reaction of production of hydrogen (H2) and oxygen (O2) gas resulting from the dissociation of water after injecting a direct electric current into an alkaline solution, generally potassium hydroxide (KOH) or sodium hydroxide (NaOH).

[0008] Each electrolytic cell, considered as a mainly metallic and conductive part (but some parts of which may be non-metallic), is generally composed of two bipolar plates, framing two interlayers (better known under the English term "flow field material"), themselves framing two electrodes generally in the form of plates or grids or metallic fabrics. In the case of an alkaline electrolyzer cell, said electrodes are generally made of nickel. The two electrodes (a cathode and an anode) are separated by a membrane (also called a diaphragm or porous separator in the case of the alkaline electrolyzer) which ensures electrical insulation between the two electrodes, the separation of gases as well as ionic conduction within the electrolytic cell.

[0009] The interlayer has two functions: i) to provide a low resistivity metallic path between each bipolar plate and the associated electrode and ii) to allow proper circulation of the electrolytic solution for cooling the electrolyzer stack and transporting the generated gases.

[0010] The name bipolar plate comes from the fact that as the electrolytic cells are all placed next to each other, an N bipolar plate will have a potential:

[0011] - higher compared to the downstream N+l bipolar plate, so that the N bipolar plate will play the role of anode within an electrolytic cell defined by the N and N+l bipolar plates;

[0012] - lower compared to the upstream bipolar plate Nl, so that the bipolar plate N will play the role of cathode within an electrolytic cell defined by the bipolar plates Nl and N .

[0013] Among the other metal parts, in addition to the bipolar plates, are listed the bottom plates (allowing to delimit the set of electrolytic cells and to ensure the clamping of said electrolytic cells between them and their sealing). Indeed, the electrolyzer stack ends with two bottom plates located just before the first electrolytic cell and just after the last stacked electrolytic cell, in other words one bottom plate is located upstream of the block of electrolytic cells and the other bottom plate is placed downstream of the latter in order to physically delimit the two ends of said block of electrolytic cells.Furthermore, an electrolyzer stack also generally comprises two distribution plates (which allow the power supply and electrical distribution of the electrolytic cells), each electrical distribution plate being arranged between respectively one of the bottom plates and the block of electrolytic cells. When the electrolyzer is pressurized in order to produce gases in a pressure state already higher than atmospheric pressure, it turns out that an electrolyzer stack is subjected to very high pressures, whether internal or external to said electrolyzer stack, which generally has the consequence of deforming the distribution plates which follow the movement of the electrolytic cells and the bottom plates.

[0014] This then causes a deformation of the electrolytic cells adjacent to the distribution plates which themselves cause a deformation of the neighboring electrolytic cells, etc., so that the deformation is nevertheless less and less significant as one moves away from the distribution plates.

[0015] Therefore, the electrolytic cells at the ends of the electrolytic cell block do not have the same shape as the other electrolytic cells and in particular do not respect the parallelism of the other electrolytic cells.

[0016] This deteriorates the quality of the electrical contacts within the electrolytic cells. This causes heterogeneity in the electrical current flowing in the electrolytic cell block, which greatly impairs the performance of the electrolyser stack.

[0017] SUBJECT OF THE INVENTION

[0018] An aim of the invention is to improve the homogeneity of the electric current in the different electrolytic cells of an electrolyzer stack.

[0019] SUMMARY OF THE INVENTION

[0020] To this end, according to the invention, an electrical distribution plate for an electrolyzer cell is provided, said electrical distribution plate comprising two main faces, the first face being intended to be turned towards a block of electrolytic cells of the electrolyzer cell and the second face being intended to be turned towards a bottom plate of the electrolyzer cell, said electrical distribution plate comprising at least one recess provided on the second main face, said electrical distribution plate further comprising at least one orifice passing through said electrical distribution plate so as to open at a first end on the first face and to open at a second end on the second face, the orifice opening at its second end:

[0021] - at the level of the recess, and / or

[0022] - outside the recess, the electrical distribution plate then comprising at least one groove opening into the orifice on the one hand and into the recess on the other hand.

[0023] The invention thus cleverly allows an electrolytic solution circulating in the block of electrolytic cells to pass through the electrical distribution plate in order to be able to fill the space present between the electrical distribution plate and the base plate. A balancing of the pressures applied in service on said electrical distribution plate is then possible, thus greatly limiting, or even completely eliminating, a deformation of said electrical distribution plate, deformation which will therefore not be transmitted to the electrolytic cells neighboring said electrical distribution plate.

[0024] Optionally, the electrical distribution plate comprises at least one second orifice passing through said electrical distribution plate so as to open at a first end on the first face and to open at a second end on the second face, the second orifice opening at its second end:

[0025] • at the level of the recess, and / or

[0026] • outside the recess, the electrical distribution plate then comprising at least one groove opening into the second orifice on the one hand and into the recess on the other hand.

[0027] Thus, in this embodiment where more than one orifice is provided in the electrical distribution plate, when the electrolyser cell is put into service, the orifices can allow the gas present in the space delimited between the electrical distribution plate and the associated bottom plate to be evacuated by the circulation of an electrolytic solution in this space, said solution opening into the space through one of the orifices and exiting the space through the other of the orifices.

[0028] Optionally, the groove extends radially.

[0029] Optionally, the groove has a U-shaped cross-section.

[0030] Optionally, the electrical distribution plate has at least one additional groove opening into the hole on the one hand and into the recess on the other hand.

[0031] Optionally, the electrical distribution plate comprises several grooves arranged in its first main face and / or its second main face, the grooves being of smaller dimensions and / or fewer in number on one of the main faces of the electrical distribution plate.

[0032] Optionally, the orifice has an oblong cross-section at least at one of the main faces.

[0033] Optionally, the orifice has a cross-section that varies between its first end and its second end. Optionally, the first orifice and the third orifice (are separated from each other at the first main face and / or the second main face by at least 120 degrees.

[0034] Optionally the first orifice and the second orifice are juxtaposed.

[0035] Optionally, the electrical distribution plate includes a second recess made on its first main face.

[0036] Optionally, the orifice is provided in the electrical distribution plate so as to connect the first recess with the second recess.

[0037] The invention also relates to an electrolyzer cell, comprising at least one electrical distribution plate according to one of the preceding claims.

[0038] Other characteristics and advantages of the invention will emerge from reading the following description of particular and non-limiting embodiments of the invention.

[0039] BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Reference will be made to the attached drawings, including:

[0041] Figure 1 is a side view of an electrolyzer stack comprising two electrical distribution plates according to a first embodiment of the invention,

[0042] Figure 2 is an exploded view of a portion of the electrolyzer stack shown in Figure 1,

[0043] Figure 3 is a perspective view of the rear of the electrical distribution board shown in Figure 2,

[0044] Figure 4 is a radial longitudinal sectional view of the electrical distribution plate shown in Figure 3, said section being provided at a portion of the holes and recesses of the electrical distribution plate,

[0045] Figure 5 is a view of an electrical distribution plate according to a second embodiment of the invention, with two enlargements of portions of said electrical distribution plate.

[0046] DETAILED DESCRIPTION OF THE INVENTION

[0047] With reference to figures 1 to 4, an electrolyzer stack 1 extends longitudinally in a general direction A.

[0048] The electrolyzer stack 1 comprises a block 2 of electrolytic cells which comprises at least two electrolytic cells which are mounted adjacent to each other in the general direction A. Within the block 2, the electrolytic cells are mounted in parallel from a fluidic point of view and in series from an electrical point of view.

[0049] At both ends (along the general direction A) of block 2, the electrolyser stack 1 has two bottom plates 3 and 4.

[0050] These bottom plates 3 and 4 form supports between which the electrolytic cells are compressed so that the electrolyser stack 1 is sealed and so that a good quality electrical contact is created inside the electrolytic cells. In addition, the bottom plates 3 and 4 make it possible to withstand the forces generated by the internal pressure in block 2 as well as the external forces in block 2 necessary to ensure the compression of block 2.

[0051] Furthermore, the electrolyser stack 1 comprises a first distribution plate 5 associated with the first bottom plate 3 and a second distribution plate 6 associated with the second bottom plate 4.

[0052] The said distribution plates 5 and 6 play the role of electrical conductor and current distributor.

[0053] The first distribution plate 5 is associated here with the negative terminal and is therefore subsequently called “negative distribution plate 5”, it is arranged downstream of the block 2. The second distribution plate 6 is associated here with the positive terminal and is therefore subsequently called “positive distribution plate 6”, it is arranged upstream of said block 2.

[0054] The concepts “upstream” and “downstream” are understood according to the direction of flow of the current through block 2.

[0055] The positive electrical distribution plate 6 is associated with the positive terminal of the electrolyser cell 1. For this purpose, a portion of the main internal face of the second bottom plate 4 (main face facing the block 2 and in particular the electrical distribution plate 6) is covered with a pad made of electrically insulating material. Said portion is for example arranged in the centre of said main internal face.

[0056] The negative electrical distribution plate 5 is associated with the negative terminal of the electrolyzer cell 1.

[0057] The first bottom plate 3 will be at the same potential as that of the negative electrical distribution plate 5 and also serves as a gateway for the supply of an electrolytic solution and the exhaust of this same solution charged with the gases formed during electrolysis in the block 2.

[0058] The negative terminal is in this case at zero potential or at that of the earth in order not to conduct current via the fluid supplies and returns. Thus, holes are provided in said bottom plate 3. Said holes often have a different section between the two main faces of said bottom plate 3. For example, the external main face (the one facing the outside of the block 2) has one or two holes (for example cylindrical in shape) for the supply of electrolytic solution and two holes for the evacuation of electrolytic reaction products in addition to the heated electrolytic solution. Three or four holes are drilled on the internal main face (opposite the external main face) of said bottom plate 3 for the same purpose, and for example oblong holes to improve the distribution or collection of fluids.For example, the holes in the outer main face are equipped with suitable flanges for connecting the inlet and return pipes of the electrolytic solution. Furthermore, the electrolyzer stack 1 is here supplied with direct current.

[0059] For example, the positive electrical distribution plate 6 has a potential of typically 700 Volts while the negative electrical distribution plate 5 has a potential of 0 Volts. The supply and evacuations of electrolytic solution are carried out at the level of the negative electrical distribution plate 5 and the bottom plate 3, said negative electrical distribution plate 5 having a potential of 0 Volts which avoids any current leakage as has already been indicated above.

[0060] Inside the electrolyser stack 1, the current passes through the electrolytic solution through membranes which will be introduced below. Within the block 2 there are seals 12: these seals 12 are chosen from a material having an electrical resistivity much greater than that of the electrolytic solution.

[0061] The electrolyser cell 1 also comprises an end seal 11 arranged between the positive electrical distribution plate 6 and the bottom plate 4. However, the bottom plate 4 is grounded so that the potential difference at said end seal 11 reaches the same value as that of the voltage applied between the positive and negative terminals of the electrolyser cell 1, for example, typically 700 Volts.

[0062] As a result, the bottom plate 4 is electrically insulated from the block 2.

[0063] The end seal 11 may be formed as a layer of electrically insulating material, said layer being arranged between the bottom plate 4 and the positive electrical distribution plate 6.

[0064] The layer, made of electrically insulating material, is for example an added disc or a deposit made on the bottom plate 4 and / or the positive electrical distribution plate 6. The bottom plate 3 not being at a different potential from that of the adjacent negative electrical distribution plate 5, this electrical insulation is not necessary on this side of the electrolyser stack 1.

[0065] The electrolyzer stack 1 comprises means for fixing the different electrolytic cells together by common clamping.

[0066] For example, the fixing means comprise a plurality of tie rods 7. Each tie rod 7 extends rectilinearly in the electrolyser stack 1. Each tie rod 7 thus extends longitudinally in the electrolyser stack 1 parallel to the general direction A. Each tie rod 7 is shaped into a rod.

[0067] The tie rods 7 therefore all extend parallel to each other.

[0068] The tie rods 7 are positioned around the perimeter of the various electrolytic cells. Preferably, the tie rods 7 are distributed all around the block 2 and preferably at a regular interval.

[0069] The tie rods 7 extend through the bottom plates 3 and 4 of the electrolyser stack 1, through specific holes in said bottom plates 3 and 4, and thus each have two ends external to the block 2.

[0070] Preferably, the tie rods 7 are partially covered with a sleeve made of electrically insulating material. This prevents short circuits between the electrolytic cells in the event of contact or projection. For example, the sleeve extends over the entire section of the tie rod 7 arranged between the two base plates 3 and 4.

[0071] Preferably, the ends of the tie rods 7 are threaded.

[0072] For example, the end threads are rolled threads. Rolled threads will have the advantage of making the machining of the tie rods 7 easier, especially if the tie rods 7 are of a significant length, for example several meters long.

[0073] The fixing means also comprise nuts 8 screwed onto the ends of the tie rods 7.

[0074] The nuts 8 make it possible to constrain the two bottom plates 3 and 4 together, and therefore the different electrolytic cells together, which ensures good sealing of the electrolyser stack 1.

[0075] Preferably, the fixing means also comprise means for prestressing the two bottom plates 3 and 4 between them, and therefore the different electrolytic cells between them. Said prestressing means also make it possible to absorb the deformations and / or variations in thickness of the elements constituting the electrolyser stack 1, due to thermal expansion or variations in the external and internal mechanical stresses of the electrolyser stack 1 (such as for example the internal pressure of the electrolyser stack 1).

[0076] The prestressing means are received on the ends of the tie rods 7 so as to be arranged, for a given end, between the nearest base plate (3 or 4) and the nuts 8 arranged on the same end.

[0077] For example, the fixing means comprise spring washers 9 such as Belleville washers. The spring washers 9 are received on the ends of the tie rods 7.

[0078] The spring washers 9 are more precisely arranged here on each tie rod 7, at the level of the external part of said tie rod 7, when the latter has passed through the nearest base plate (3 or 4).

[0079] In the present case, all the electrolytic cells of the electrolyser stack 1 are identical to each other. Each electrolytic cell comprises a central membrane (the membranes having already been mentioned above) which is framed by two electrodes (an anode and a cathode, respectively) which are themselves framed by two interlayers (or "flow field material" in English) which are themselves framed by two bipolar plates 10. Furthermore, the electrolytic cell also comprises a seal 12 (the existence of which has already been mentioned above) which is compressed between the two bipolar plates 10 of the electrolytic cell and, for the end cells, between said end cells and the associated electrical distribution plates (5 or 6).

[0080] The electrolytic cell is for example the electrolytic cell described in application EP 22200483.0 of the present applicant.

[0081] The electrolyzer cell 1 is for example the electrolyzer cell described in application EP 22200480.6 of the present applicant.

[0082] As already indicated above, the electrolyser stack 1 comprises different plates, namely:

[0083] • category 1: bottom plates 3, 4,

[0084] • category 2: the bipolar plates 10, and • category 3: the distribution plates 5, 6. Each category of plates has different specificities with respect to the electrolyser stack 1 from the point of view of mechanical support (in view of all the pressures exerted on it) as well as the distribution of the electric current within it. The bottom plates 3, 4 support the electrolyser stack 1 and thus undergo considerable pressure forces. As a result, this is the category of plates with the greatest thickness. Despite this, the bottom plates 3, 4 tend to deform, particularly in their centre. A bottom plate is thus neither a bipolar plate nor a distribution plate.

[0085] The bipolar plates 10 are such that if a bipolar plate 10 is not deformed, it is uniformly traversed over its entire surface by the electric current. It can thus transmit to the bipolar plate 10 which follows it the electric current equally uniformly. It is therefore understood that the current comes either from a current distribution plate, or from an adjacent bipolar plate 10. A bipolar plate is thus not directly powered. Furthermore, a bipolar plate 10 is intended to be axially traversed by the electric current. A bipolar plate 10 is preferably traversed by the current in a direction orthogonal to the plane forming one of the main surfaces of the bipolar plate 10. This is the category of plates having the least thickness. A bipolar plate is thus neither a base plate nor a distribution plate.

[0086] The distribution plates 5, 6 are on the other hand supplied directly (for example via cables or metal bars, optionally made of copper, which are external to the cell block of the electrolyser stack and which are connected to external protrusions of the cell block, protrusions connected to one or other of the distribution plates 5, 6). Preferably, the protrusion(s) extend radially relative to one of the distribution plates. Thus the electrical distribution plate(s) receives the current on its perimeter in one or more location(s) and distributes it uniformly over its entire surface.

[0087] The distribution plates 5, 6 are configured to be able to transmit to the bipolar plates 10 the most uniformly distributed electric current on the surfaces of the bipolar plates. While the current arrives radially in the distribution plate 5, the latter distributes it to the nearest bipolar plate 10 so that the current passes axially through said bipolar plate 10.

[0088] A distribution plate is therefore neither a base plate nor a bipolar plate. In fact, a distribution plate receives the electric current radially before distributing it in an axial direction to the block of electric cells.

[0089] The distribution plates 5, 6 are less thick than the base plates 3, 4 but thicker than the bipolar plates 10.

[0090] Consequently, in the prior art, if one of the bottom plates deforms, the electrical distribution plate adjacent to it will also deform and will therefore not be able to distribute the current uniformly to the bipolar plate adjacent to it. This will obviously have repercussions on a certain number of electrolytic cells, more particularly the first electrolytic cells located at the entrance to the electrolyser stack. Among the other consequences linked to this non-uniform distribution of the current, it will also appear:

[0091] • higher energy consumption on said first electrolytic cells at least in the first operating times of the electrolyzer stack,

[0092] • temperature differences within the same electrolytic cell since the current will not flow uniformly through the cell.

[0093] All of this is usually damaging to the electrolyzer cell.

[0094] We will therefore propose below specific distribution plates 5, 6 (which are therefore neither base plates nor bipolar plates) to counter as much as possible the disadvantages described above.

[0095] The two electrical distribution plates 5, 6 are identical here.

[0096] The following description of the positive electrical distribution plate 6 is therefore also applicable here to the negative electrical distribution plate 5.

[0097] The positive electrical distribution plate 6 thus comprises two main faces, the first face 21 being turned towards the block 2, and the second face 22 turned towards the associated base plate (in this case the base plate 4 for the positive electrical distribution plate 6 but the base plate 3 if we consider the other negative electrical distribution plate 5).

[0098] Subsequently, the X and Y axes are defined, which form a plane in which one of the main faces of the positive electrical distribution plate 6 extends, and the Z axis, which is normal to said XY plane.

[0099] When the positive electrical distribution plate 6 is in place in the electrolytic cell which is itself in place in the electrolyzer stack 1, the Z axis here coincides with the general direction A.

[0100] The thickness of the positive electrical distribution plate 6 (along the Z axis) is less than its other dimensions.

[0101] The positive electrical distribution plate 6 is shaped so as to have a cross-section (in an XY plane) in any geometric shape (square, rectangular, disc-shaped, etc.). The negative electrical distribution plate 5 here has a disc-shaped cross-section.

[0102] The positive electrical distribution plate 6 comprises a first recess 24 provided on the second main face 22 facing the bottom plate 4.

[0103] According to a first option, the positive electrical distribution plate 6 is shaped so that its first main face 21 is devoid of any recess. The first main face 21 is then in contact over its entire central zone with the bipolar plate 10 of the first immediately adjacent electrolytic cell (the zone of the bipolar plate 10 which is itself in contact with said central zone is therefore also flat in order to ensure uniform current transfer).

[0104] Alternatively, according to a second option, the positive electrical distribution plate 6 comprises a second recess 23 provided on the first main face 21 facing the adjacent bipolar plate 10. The positive electrical distribution plate 6 then directly plays the role of a bipolar plate 10 and thus partly forms the first electrolytic cell of the block 2 with another bipolar plate 10 (whose facing face conforms to the same geometry as that of the main face 21 of the positive electrical distribution plate 6). In the example illustrated in the figures, the positive electrical distribution plate 6 comprises a recess 23 and 24 on each of its main faces, respectively 21 and 22, but this option is absolutely not limiting.

[0105] The two recesses 23, 24 may be different or identical to each other.

[0106] In the example illustrated, the two recesses 23, 24 are identical.

[0107] Each recess extends from the associated main face towards the other recess without, however, opening into the other recess. Each recess 23, 24 is for example provided in the center of the associated main face. Each recess 23, 24 is for example provided so as to extend coaxially to the Z axis.

[0108] Each recess 23, 24 is shaped so as to have a cross-section (in an XY plane) in any geometric shape (square, rectangular, disc, etc.). Each recess 23, 24 here has a disc-shaped cross-section. For example, each recess 23, 24 has an overall bowl-shaped shape, the bottom of which may or may not be rounded.

[0109] Around the recesses 23, 24, the positive electrical distribution plate 6 has an external periphery 25 - which here is of annular cross-section. The external periphery 25 constitutes in the present case the main face 21 (or 22 depending on the periphery considered) of said bipolar plate 10.

[0110] The positive electrical distribution plate 6 comprises in a particular embodiment of the invention:

[0111] - a first orifice 26 passing through the positive electrical distribution plate 6 so as to open at a first end on the first face 21 outside the second recess 23 and to open at a second end on the second face 22 outside the second recess 23,

[0112] - a second orifice 27 passing through the positive electrical distribution plate 6 so as to open at a first end on the first face 21 outside the first recess 24 and to open at a second end on the second face 22 outside the second recess 23.

[0113] In this embodiment, each of said orifices 26, 27 thus extends in the external periphery 25. Each orifice 26, 27 extends rectilinearly in a direction parallel to the Z axis.

[0114] Optionally, each orifice 26, 27 has a cross-section (in a plane parallel to the XY plane) that is identical over its entire length (considered along the Z axis). Each orifice 26, 27 is shaped so as to have a cross-section (in a plane parallel to the XY plane) in any geometric shape (disc, oblong, etc.) and for example a disc. Preferably, the two orifices 26, 27 are arranged close to each other. For example, at the first main face 21 and / or the second main face 22, the first orifice 26 and the second orifice 27 are arranged in the same angular sector. The angular sector is for example between 5 and 25 degrees and preferably between 10 and 20 degrees and for example between 15 and 20 degrees.The two orifices 26, 27 are associated with orifices of the adjacent electrolytic cell allowing the circulation of the electrolytic solution or gases from or to the block 2. Preferably, the positive electrical distribution plate 6 comprises a third orifice 28 passing through the positive electrical distribution plate 6 so as to open at a first end on the first face 21 outside the first recess 24 and to open at a second end on the second face 22 outside the second recess 23. The third orifice 28 thus extends in the external periphery 25. The third orifice 28 extends rectilinearly in a direction parallel to the Z axis.The plane comprising the Y and Z axes separates the positive electrical distribution plate 6 into two: preferably, the third orifice 28 extends in the part of the positive electrical distribution plate 6 opposite that in which the first orifice 26 and the second orifice 27 extend.

[0115] Preferably, the third orifice 28 is diametrically opposite the second orifice 27.

[0116] Preferably, the positive electrical distribution plate 6 may comprise a fourth orifice 29 passing through the positive electrical distribution plate 6 so as to open at a first end on the first face 21 outside the first recess 24 and to open at a second end on the second face 22 outside the second recess 23.

[0117] The fourth orifice 29 thus extends into the external periphery 25.

[0118] The fourth orifice 29 extends rectilinearly in a direction parallel to the Z axis.

[0119] The plane comprising the Y and Z axes artificially separates the positive electrical distribution plate 6 into two: preferably, the fourth orifice 29 extends in the part of the positive electrical distribution plate 6 opposite that in which the first orifice 26 and the second orifice 27 extend. Preferably, the fourth orifice 29 is diametrically opposite the first orifice 26.

[0120] The third orifice 28 as the fourth orifice 29 are optionally shaped to have a cross-section (in a plane parallel to the XY plane) identical over their entire length (considered along the Z axis). For example, the third orifice 28 as the fourth orifice 29 are shaped so as to have a cross-section (in a plane parallel to the XY plane) in any geometric shape (disc, oblong, etc.) and for example a disc.

[0121] Thus, the third orifice 28 and the fourth orifice 29 are arranged close to each other.

[0122] For example, at the level of the first main face 21 and / or the second main face 22, the third orifice 28 and the fourth orifice 29 are arranged in the same angular sector. The angular sector is for example between 5 and 25 degrees and preferably between 10 and 20 degrees and for example between 15 and 20 degrees.

[0123] The third orifice 28 and the fourth orifice 29 are associated with orifices of the adjacent electrolytic cell allowing the circulation of the electrolytic solution or gases from or to the block 2.

[0124] The positive electrical distribution plate 6 thus described therefore comprises two orifices and preferably two pairs of two orifices, each pair being arranged opposite one another while the two orifices of the same pair are juxtaposed.

[0125] At the level of the first main face 21 and / or the second main face 22, the first orifice 26 (respectively the second orifice 27) is spaced from the third orifice 28 (respectively the fourth orifice 29) by an angular sector greater than 120 degrees.

[0126] Preferably, the orifices 26, 27, 28, 29 are arranged so as to each face one of the orifices passing through the different electrolytic cells of the block 2 and forming the channels for conveying or discharging the electrolysis solution and the gases. The orifices 26, 27, 28, 29 are for example each coaxial with one of said orifices passing through the different electrolytic cells of the block 2 and forming the channels for conveying or discharging the electrolysis solution and the gases.

[0127] Preferably, the orifices 26, 27, 28, 29 are arranged so as to each be opposite one of said orifices passing through the different electrolytic cells of the block 2 and forming the channels for conveying or discharging the electrolysis solution and the gases and located at the lowest and highest points of the block 2 (along the X axis when the electrolyser cell 1 is used in a horizontal position, its general direction A then being horizontal).

[0128] In the example described, the four orifices are provided in the external periphery. In this case, preferably, the positive electrical distribution plate 6 comprises at least one first groove 31 opening at a first end into the first orifice 26 on the one hand and at a second end into the first recess 24 on the other hand. The first groove 31 is provided on the first main face 21 of the positive electrical distribution plate 6. The first groove 31 here extends rectilinearly in a direction R towards the general direction A. The first groove 31 preferably extends radially.

[0129] Optionally, the first groove 31 has a cross-section (along a cutting plane normal to the direction R) identical over its entire length (considered along the direction R). The cross-section of the first groove 31 (along a cutting plane normal to the direction R) is in any geometric shape (U-shaped, square or rectangular U-shaped, rounded, arc-shaped, etc.). The first groove 31 does not open into the second recess 23.

[0130] Preferably, the positive electrical distribution plate 6 comprises at least one second groove 32 opening at a first end into the first orifice 26 on the one hand and at a second end into the second recess 23 on the other hand. The second groove 32 is provided on the second main face 22 of the positive electrical distribution plate 6. The second groove 32 here extends rectilinearly in a direction R' towards the general direction A. The second groove 32 preferably extends radially.

[0131] Optionally, the second groove 32 has a cross-section (along a cutting plane normal to the direction R') identical over its entire length (considered along the direction R'). The cross-section of the second groove 32 (along a cutting plane normal to the direction R') is in any geometric shape (U-shaped, square or rectangular U-shaped, rounded, arc-shaped, etc.). The second groove 32 does not open into the second recess 23.

[0132] The first groove 31 and the second groove 32 are identical here. The first groove 31 and the second groove 32 extend here parallel to each other (the directions R and R' are thus parallel to each other).

[0133] Preferably, all the orifices of the positive electrical distribution plate 6 are associated with at least one groove and preferably at least two grooves like the first orifice 26.

[0134] Thus: two grooves start from the second orifice 27 to open one into the first recess 24 and the other into the second recess 23, the two grooves optionally extending parallel to each other, two grooves 33, 34 start from the third orifice 28 to open one into the first recess 24 and the other into the second recess 23, the two grooves optionally extending parallel to each other, two grooves start from the fourth orifice 29 to open one into the first recess 24 and the other into the second recess 23, the two grooves optionally extending parallel to each other. In a particular embodiment, the different grooves of the positive electrical distribution plate 6 are for example all identical to each other.Furthermore, the various grooves of the positive electrical distribution plate 6 are all provided either in the first main face 21 or in the second main face 22.

[0135] Furthermore, due to the diametrically opposed arrangement of the orifices, two by two in a particular non-limiting embodiment, each groove associated with one of the orifices extends in the extension of a groove associated with another of the orifices so that the grooves extend along the same axis two by two.

[0136] In the example described, the positive electrical distribution plate 6 has a central symmetry with respect to the X axis and is also symmetrical along a central symmetry plane with respect to the Y axis. This is not limiting and the positive electrical distribution plate 6 may not be symmetrical along a central symmetry plane parallel to the X and Y axes and / or along a central symmetry plane parallel to the Y and Z axes. In service, the electrolytic solution which circulates in the block 2 will be able to circulate from the interior of the block 2 to the space present between each electrical distribution plate 5, 6 and the associated bottom plate 3, 4 thanks to the third orifice 28 and the fourth orifice 29, which will ensure balancing of the pressures applied to the two main faces 21, 22 of each of the electrical distribution plates 5, 6.This prevents them from deforming when using the electrolyser stack 1, whereas the base plates 3, 4 will deform.

[0137] It is noted that the electrolytic solution can also circulate towards said space as far as block 2 thanks to the first orifice 26 and the second orifice 27. This makes it possible to easily purge said space when the electrolytic solution is evacuated, for example, by suction, from block 2.

[0138] It is understood that the grooves facilitate the circulation of the fluid through the electrical distribution plates 5, 6.

[0139] The distribution plates 5, 6 thus remain flat during all operating cases of the electrolyser stack even in the cases of transitions. Indeed, their particular geometry allows the electrolytic solution to pass on each side of the distribution plate considered. In particular, the orifices 26, 27 make it possible to supply the two faces of the electrical distribution plate so that the electrolytic solution exerts the same force on each of the two faces and preferably exerts the same pressure force distributed uniformly over the entire surface of said faces. With such a configuration, each bottom plate cannot come into contact with the electrical distribution plate which is adjacent to it since the electrolytic solution is present between them and exerts the same uniform pressure on the two faces of said distribution plate.

[0140] Advantageously, the electrolytic solution allowing pressure balancing has the same pressure and the same potential on each side of the associated distribution plate.

[0141] Advantageously, each distribution plate 5, 6 has a recess 23, 24 which is provided in the center of the associated main face. This is particularly advantageous because the bottom plates tend to deform in their center. With this particular geometry of the distribution plates 5, 6, the risk of the bottom plates coming into contact with the distribution plates adjacent to them is further limited. This is particularly advantageous for the case of starting the electrolyzer stack 1 when the electrolytic solution is not yet in sufficient quantity between the bottom plate and the associated distribution plate to exert uniform pressure on both sides of said distribution plate.

[0142] Of course, the electrical distribution plates 5, 6 can take a form other than that which has just been described.

[0143] Thus, and as illustrated in Figure 5:

[0144] 1°) At least one of the orifices 100 may have a cross-section other than a circular cross-section and for example have an oblong cross-section.

[0145] 2°) At least one of the orifices 100 may have a cross-section which varies between the first main face 21 and the second main face 22 of the positive electrical distribution plate 6. For example, at least one orifice 100 may have a cross-section of circular section at the level of the first main face 21 (for the supply and / or evacuation of the electrolytic solution) and an enlarged section (for example oblong) at the level of the second main face 22 (to improve the distribution and / or the collection of the electrolytic solution).

[0146] 3°) At least one of the grooves may have a cross-section which varies along its length.

[0147] 4°) At least one of the orifices 100 may not extend rectilinearly and / or parallel to the Z axis. For example, at least one of the orifices 100 may extend rectilinearly along an axis transverse to the Z axis and optionally extend so that it opens at the level of the second main face 22 more in the center of the positive electrical distribution plate 6 than at the level of the first main face 21 (or vice versa).

[0148] 5°) The number of orifices may be different from what has been indicated. For example, the positive electrical distribution plate 6 may comprise between two and four pairs of orifices and for example three pairs of orifices. However, an attempt is made to minimize the dimensions and / or the number of orifices to limit as much as possible the influence on the flow rate of the electrolytic solution in the block.

[0149] 6°) The positive electrical distribution plate 6 may not be symmetrical according to a central symmetry with respect to . For example, there may be a different number of orifices on each of the halves of the external periphery 25 of the positive electrical distribution plate 6 (half delimited by a plane passing through the axes Y and Z) and / or only one of the main faces of the positive electrical distribution plate 6 may have a recess.

[0150] 7°) The positive electrical distribution plate 6 may comprise at least one orifice which is not associated with a groove and in particular if the orifice is already arranged so as to open at each of its ends into the two recesses of the positive electrical distribution plate 6 so as to put the two recesses in communication.

[0151] 8°) A different number of grooves than a single groove may be associated with at least one of the orifices 100 and for example two grooves and for example three grooves and for example a number of grooves between four and ten grooves. The grooves may thus be regularly distributed along the associated orifice or on the contrary be irregularly distributed along the associated orifice 100 (for example to be all grouped on the same end of the associated orifice or mainly grouped on said end).

[0152] 9°) For at least one orifice 100, the number and / or the shape of the associated groove(s) may be different depending on whether the first end of the orifice 100 or its second end is considered. For example, a greater number of grooves and / or one or more grooves of larger dimension(s) may be associated with the end of the orifice 100 opening onto the first main face 21 than the end of the same orifice 100 opening onto the second main face 22.

[0153] 10°) For at least two orifices 100 (one allowing the introduction of the electrolytic solution into the space between the electrical distribution plate 5, 6 and the bottom plate 3, 4 and the other allowing its circulation), the number and / or the shape of the associated groove(s) may be different depending on whether the orifice 102 associated with the introduction or the orifice 100 associated with the expulsion is considered. For example, a greater number of grooves and / or one or more grooves of larger dimension(s) may be associated with an orifice allowing circulation (or vice versa depending on the intended needs). This will, for example, facilitate the cleaning of the block 2.

[0154] Of course, the invention is not limited to the embodiment described but encompasses any variant falling within the scope of the invention as defined by the claims.

[0155] The electrolyzer stack may be used horizontally, vertically, or in any other position. The electrolyzer stack may be assembled horizontally, vertically, or in any other position. Preferably, the electrolyzer stack will be assembled vertically and used horizontally.

[0156] It will be possible to have only one orifice associated with the introduction of the electrolytic solution and a single orifice associated with its removal. However, it will be preferable to have two orifices associated with the introduction of the electrolytic solution and / or two orifices associated with the removal for reasons of redundancy in the event that one of the orifices becomes blocked. In general, the electrical distribution plate may have only one orifice opening at each of its ends onto one of the respective main faces of the electrical distribution plate.

[0157] Similarly, it is preferable to have two grooves associated with each end of each orifice for redundancy reasons.

[0158] The different orifices may not be identical to each other.

[0159] The different grooves may not be identical to each other.

[0160] The two electrical distribution plates, each associated with one end of the block, may be different and not identical to each other as mentioned above.

[0161] The electrical distribution plate may only have one reinforcement and not two as indicated.

[0162] The electrical distribution plate may include at least one orifice not opening at at least one of its ends on the external periphery of the associated main face (and for example opening in the central zone of said main face and for example in the recess possibly present on said main face).

[0163] For example, the electrical distribution plate may include at least one orifice opening at least at one of its ends into a recess in said electrical distribution plate. Optionally, the orifice will open at least at one of its ends at a position sufficiently close to the external periphery of one of the main faces to allow complete or almost complete emptying (emptying of a liquid and / or a gas) present in the space between the electrical distribution plate in question and the facing bottom plate. Optionally, this orifice may be arranged so as to open at a first end into the recess in the first main face of the electrical distribution plate and to open at a second end into the recess in the second main face of said electrical distribution plate so as to put the two recesses in communication.

Claims

CLAIMS 1. Electrical distribution plate (5, 6) for an electrolyzer cell (1), the electrical distribution plate (5, 6) comprising two main faces, the first face (21) being intended to be turned towards a block (2) of electrolytic cells of the electrolyzer cell (1) and the second face (22) being intended to be turned towards a bottom plate (4) of the electrolyzer cell (1), the electrical distribution plate (5, 6) comprising at least one recess (24) provided on the second main face, the electrical distribution plate (5, 6) further comprising at least one orifice passing through the electrical distribution plate (5, 6) so as to open at a first end on the first face and to open at a second end on the second face, the orifice opening at its second end: - at the level of the recess, and / or - outside the recess, the electrical distribution plate (5, 6) then comprising at least one groove opening into the orifice on the one hand and into the recess on the other hand.

2. Electrical distribution plate (5, 6) according to claim 1, in which the groove extends radially.

3. Electrical distribution plate (5, 6) according to one of claims 1 to 2, in which the groove (31) has a U-shaped cross-section.

4. Electrical distribution plate (5, 6) according to one of claims 1 to 3, comprising at least one groove additional opening into the orifice on the one hand and into the recess on the other hand.

5. Electrical distribution plate (5, 6) according to one of claims 1 to 4, comprising several grooves formed in its first main face (21) and / or its second main face (22), the grooves being of smaller dimensions and / or fewer in number on one of the main faces of the electrical distribution plate (5, 6).

6. Electrical distribution plate (5, 6) according to one of the preceding claims, in which the orifice has an oblong cross-section at least at one of the main faces.

7. Electrical distribution plate (5, 6) according to one of the preceding claims, in which the orifice has a cross-section which varies between its first end and its second end.

8. Electrical distribution plate (5, 6) according to one of the preceding claims, in which the orifice is a first orifice, the electrical distribution plate (5, 6) further comprising a second orifice passing through the electrical distribution plate (5, 6) so as to open at a first end onto the first face (21) and to open at a second end onto the second face (22), the second orifice being opened at its second end: • at the level of the recess (24), and / or • outside the recess, the electrical distribution plate then comprising at least one groove opening into the second orifice on the one hand and into the recess on the other hand.

9. Electrical distribution plate (5, 6) according to claim 8, wherein the first orifice (26) and the third orifice (28) are separated from each other at the first main face and / or the second main face by at least 120 degrees.

10. Electrical distribution plate (5, 6) according to claim 8, in which the first orifice (26) and the second orifice (27) are juxtaposed.

11. Electrical distribution plate (5, 6) according to one of the preceding claims, comprising a second recess provided on its first main face.

12. Electrical distribution plate (5, 6) according to claim 11, in which the orifice is provided in the electrical distribution plate (5, 6) so as to place the first recess in communication with the second recess.

13. Electrolyzer cell (1), comprising at least one electrical distribution plate (5 or 6) according to one of the preceding claims.

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