Electrolysis apparatus stack with low leakage current

Abstract

Disclosed is an electrolysis apparatus stack comprising two base plates clamped between a stack of elements having electrolysis cells, and at least one intermediate plate (30) clamped within the stack of elements. The intermediate plate (30) has a thickness comprising at least one electrolyte supply duct, a first duct for releasing a first electrolysis product, and a second duct (33) for releasing a second electrolysis product, each of which is individually integrated into a supply network, a first discharge network, and a second discharge network. Each of the ducts (33) within the intermediate plate (30) has a length exceeding the thickness of the intermediate plate (30) and includes a folded section (34) connecting inlet and outlet ports to each other.

Description

Technical Field

[0001] The present invention relates to the field of electrolysis, and more particularly to the production of hydrogen.

Background Art

[0002] The overall architecture of an electrolyzer stack typically consists of a block of electrolysis cells stacked electrically in series and fluidly in parallel, and gaskets.

[0003] The purpose of each electrolysis cell is to facilitate the electrolysis of an electrolyte solution (such as alkaline water, pure water, raw water, salts, aqueous chloride solution, aqueous bromide solution, aqueous hydrochloric acid solution, etc.). For example, the function of an electrolyzer stack is to promote a reaction that generates gaseous dihydrogen (H2) and dioxygen (O2) as a result of the decomposition of water after injecting direct current into an alkaline solution, generally potassium hydroxide (KOH) or sodium hydroxide (NaOH).

[0004] (However, some of its parts may be non-metallic) Each electrolysis cell, regarded mainly as a metallic and conductive article, generally consists of two bipolar plates that form two flow field materials that in turn form two electrodes having generally the form of metallic plates or meshes or fabrics. In the case of an alkaline electrolyzer stack, the electrodes are generally made of nickel. The two electrodes (cathode and anode) are separated by a membrane (also called diaphragm or porous separator in the case of an alkaline electrolyzer stack) that ensures electrical insulation between the two electrodes, separation of gases, and ion conduction within the electrolysis cell.

[0005] The flow field material has two functions: i) to provide a metallic pathway with low resistivity between each bipolar plate and the associated electrode, and ii) to allow a suitable flow of the electrolyte solution for cooling the electrolysis apparatus stack and transporting the generated gas.

[0006] The name "bipolar plate" comes from the fact that all the electrolysis cells are continuous with each other, hence the name Bipolar Plate N. - Bipolar plate N will function as an anode in the electrolysis cell defined by bipolar plates N and N+1, with a higher value than the downstream bipolar plate N+1. - Bipolar plate N will function as a cathode in the electrolysis cell defined by bipolar plates N-1 and N, lower than the upstream bipolar plate N-1. It stems from the fact that it will be located at an electric potential.

[0007] Other metallic articles that are numbered include not only the bipolar plates, but also the distribution plates (which enable the supply and distribution of electricity to the electrolytic cells), as well as the base plates (which define the boundaries of groups of electrolytic cells and not only clamp the electrolytic cells together but also seal them).

[0008] Specifically, the electrolysis apparatus stack is terminated by two base plates located immediately before the first stacked electrolysis cell and immediately after the last stacked electrolysis cell; that is, one base plate is positioned upstream of the block of electrolysis cells and the other base plate is positioned downstream thereof, for the purpose of physically defining the boundary between the two ends of the block of electrolysis cells.

[0009] To ensure ion conduction within the electrolysis cell, the electrolyte solution must have high ionic conductivity. However, this high ionic conductivity presents a risk of leakage currents propagating through the electrolyte and into the network used to supply the electrolyte and release the biphasic mixture (i.e., the electrolyte and dioxygen on one side and dihydrogen on the other). These leakage currents reduce the overall efficiency of the electrolysis process.

[0010] These leakage currents can be compensated by reducing the cross-sectional area through which the conduit passes, or by using conduits made from electrical insulating material within the network for supplying the electrolyte and releasing the biphasic mixture.

[0011] The first solution involves head losses, which risk leading to poor distribution of electrolytes between electrolysis cells and difficulty in releasing the gases produced by electrolysis. The materials used in the second solution are generally polymer materials, whose properties impose limitations in terms of the pressure and temperature of the fluid flowing through the conduit.

[0012] Therefore, these two solutions are not optimal. [Overview of the project]

[0013] The objective of this invention is to propose an electrolysis apparatus stack having improved efficiency. [Means for solving the problem]

[0014] To this end, the present invention provides an electrolysis apparatus stack having a stack of elements for housing an electrolysis cell and two base plates for clamping at least one intermediate plate that is clamped within the stack of elements. The intermediate plate has a thickness on which at least one electrolyte supply conduit, a first conduit for releasing a first electrolysis product, and a second conduit for releasing a second electrolysis product are formed, and these conduits are individually integrated with the supply network, the first release network, and the second release network. Each of these conduits formed within the intermediate plate has a length greater than the thickness of the intermediate plate and has at least one segment bent to form a U-shape having two branches that extend adjacent to each other in the direction of the thickness of the intermediate plate.

[0015] Therefore, the conduit formed within the intermediate plate increases the electrical resistance of the supply and discharge networks by increasing their length without resulting in an equivalent increase in the axial size of the electrolysis stack or affecting the flow rate of the fluid flowing within the network at a given pumping capacity. Thus, this solution presents a compromise between increasing the electrical resistance of the network, which affects the overall efficiency of the electrolysis stack, and increasing the axial size of the electrolysis stack.

[0016] The electrolysis apparatus stack according to the present invention may, if necessary, - At least two intermediate plates are arranged on both sides of multiple electrolytic cells. - Multiple electrolysis cells have 1000 to 400, preferably 20 to 50, electrolysis cells. - The intermediate plate is the bipolar plate of one of the electrolysis cells. - The intermediate plate is a current distribution plate that extends between the end plate and the adjacent electrolysis cell. - having one or more of the optional characteristics that the stack of elements is configured in the vertical direction or in the horizontal direction, and having one or more of the following optional characteristics:

[0017] Other features and advantages of the present invention will become apparent upon reference to the following description of specific non - limiting embodiments of the invention.

Brief Description of the Drawings

[0018] Reference will be made to the accompanying drawings, which are as follows.

[0019] [Figure 1] FIG. 1 is a schematic exploded view of an electrolysis cell of an electrolysis apparatus stack according to a specific embodiment of the present invention. <00.valueOf(1000000000 * Math.random())>FIG. 2 is a perspective view of a bipolar plate of the electrolysis cell shown in FIG. 1. [Figure 3a] FIG. [0000083]3a is a cross - sectional view of a portion of the bipolar plate shown in FIG. 2. [Figure 3b] FIG. 3b is a cross - sectional view of a portion of the bipolar plate shown in FIG. 2, in which case the membrane of the electrolysis cell is also present. [Figure 3c] FIG. 3c is a cross - sectional view of a portion of the electrolysis cell shown in FIG. 1. [Figure 4] [[ID=​​​​​​​​​​​​Referring to various figures, the present invention relates to an electrolysis apparatus stack that houses a stack of elements extending longitudinally along a general direction A. The various elements are mostly formed by electrolysis cells 10, which will be described below.

[0021] The electrolysis apparatus stack 1 houses a block 2 of electrolysis cells 10, which has at least two electrolysis cells 10 mounted continuously to each other along a general direction A. Within block 2, the electrolysis cells 10 are mounted in parallel fluidly and in series electrically.

[0022] Two end plates or base plates 3 and 4 are present in the configuration where they are positioned at the two ends (along the general direction A) of block 2 of the electrolysis apparatus stack 1.

[0023] These base plates 3 and 4 form a support, and the electrolysis cell 10 is compressed between them so that the electrolysis apparatus stack 1 is sealed and high-quality electrical contact is generated inside the electrolysis cell 10.

[0024] Furthermore, base plates 3 and 4 are capable of withstanding not only the forces generated by the internal pressure of block 2 but also external forces of block 2, and these forces are necessary to ensure the compression of block 2.

[0025] Base plates 3 and 4 can function as conductors and current distributors.

[0026] Preferably, the electrolysis apparatus stack 1 houses a first distribution plate 5 associated with a first base plate 3 and a second distribution plate 6 associated with a second base plate 4. Thus, it is the distribution plates 5 and 6 that function as conductors and current distributors.

[0027] The first distribution plate 5 (associated with the positive terminal) is located upstream of block 2, and the second distribution plate 6 (associated with the negative terminal) is located downstream of block 2.

[0028] The concepts of "upstream" and "downstream" should be understood according to the conventional direction in which the current flows through Block 2.

[0029] The first of the two distribution plates 5 is connected to the positive terminal of the electrolysis apparatus stack 1. A portion of the inner main face of the first base plate 3 (the main face facing block 2 and especially facing distribution plate 5) is covered by a patch of electrical insulating material. The portion is located, for example, at the center of the inner main face.

[0030] The second of the two distribution plates, 6, is connected to the negative terminal of the electrolysis apparatus stack 1. The second base plate 4 is positioned at the same potential and also functions as a passage for supplying the electrolyte solution and releasing the same solution containing the gas formed during electrolysis in block 2.

[0031] Accordingly, holes are formed within the second base plate 4. These holes often have different cross-sections between the two main faces of the second base plate 4. For example, the outer main face (facing outwards from the block 2) includes at least one or two holes (e.g., formed into a cylindrical shape) for supplying the electrolyte solution and two holes for releasing electrolysis reaction products in addition to the treated electrolyte solution. For example, at least three or four holes, such as those with an elongated elliptical shape, are perforated on the inner main face (opposite the outer main face) of the second base plate 4 for the same purpose, in order to improve fluid distribution or collection. For example, the holes on the outer main face are equipped with flanges suitable for mounting arrival and return pipes for the electrolyte solution.

[0032] Furthermore, DC power is supplied to the electrolysis apparatus stack 1.

[0033] For example, the first distribution plate 5 is located at a potential of several hundred volts, while the second distribution plate 6 is located at a potential of 0 volts (the electrolysis apparatus stack 1 typically has a potential of 10 to 400, preferably 100 to 350, in which case the electrolysis cell 10 has a cell voltage of 2 volts, and preferably less than 1.85 volts, at the start of its rated life). The supply and release of the electrolyte solution occurs at the second distribution plate 6 and the second base plate 4, in which case the second distribution plate 6 is located at a potential of 0 volts, which avoids any current leakage (in this case, the potential of the second distribution plate 6 is the ground potential).

[0034] Inside the electrolysis apparatus stack 1, the current passes through the electrolyte solution across the membrane 11, which will be described below. Gaskets are present within block 2 (described later), and these gaskets are selected to be made of materials with significantly higher electrical resistance than that of the electrolyte solution.

[0035] The electrolysis apparatus stack 1 houses an end gasket (not visible in the figure) positioned between the first distribution plate 5 and the first base plate 3. The first base plate 3 is grounded such that the potential difference across the end gasket reaches the same value as the voltage applied between the positive and negative terminals of the electrolysis apparatus stack 1, for example, substantially 700 volts.

[0036] For this reason, the first base plate 3 is electrically insulated from block 2.

[0037] For example, the electrolysis apparatus stack 1 contains a layer of electrical insulating material (not visible in the figure), in which case this layer is located between the first base plate 2 and the first distribution plate 5.

[0038] The layers are, for example, further disks or deposits formed on the first base plate 3 and / or on the first distribution plate 5.

[0039] The electrolysis apparatus stack 1 houses means for securing various electrolysis cells 10 to each other by combination clamping.

[0040] For example, the fixing means accommodates multiple tie rods 7. Each tie rod 7 extends as a straight line in the stacking direction of the electrolysis apparatus stack 1. Thus, each tie rod 7 extends longitudinally within the electrolysis apparatus stack 1, parallel to the general direction A. Each tie rod 7 is configured as a bar.

[0041] Therefore, all tie rods 7 extend parallel to one another. The tie rods 7 are positioned on the boundaries of various electrolytic cells 10. Preferably, the tie rods 7 are distributed around block 2, preferably at regular intervals.

[0042] The tie rod 7 extends through the base plates 3 and 4 of the electrolysis apparatus stack 1, through specific holes in the base plates 3 and 4, and therefore each has two ends outside the block 2.

[0043] Preferably, the tie rod 7 is partially covered by a sleeve made of an electrically insulating material. This allows for avoidance of short circuits between the electrolytic cells 10 in the event of contact or sputtering. For example, the sleeve extends over the entire segment of the tie rod 7 positioned between the two base plates 3 and 4.

[0044] Preferably, the end of the tie rod 7 is threaded.

[0045] For example, the threads at the end are rolled threads. Rolled threads have the advantage of facilitating the machining of the tie rod 7, especially when the tie rod 7 has a large length, such as several meters.

[0046] The fastening mechanism also accommodates nuts 8, which are screwed onto the ends of the tie rods 7.

[0047] The nuts 8 allow the two base plates 3 and 4 to be fastened together, and therefore the various electrolysis cells 10 together, which ensures good sealing of the electrolysis apparatus stack 1 of the electrolysis cells 10.

[0048] Preferably, the fastening means also accommodate means for pre-tightening the two base plates 3 and 4 to each other, and therefore to the various electrolysis cells 10 to each other. The pre-tightening means also allows for the absorption of deformation and / or thickness variations of the elements constituting the electrolysis apparatus stack 1, which are caused by variations in thermal expansion or mechanical stress outside and inside the electrolysis apparatus stack 1 (for example, the pressure inside the electrolysis apparatus stack 1).

[0049] The pre-tightening means is received on the end of the tie rod 7 such that, for a given end, it is positioned between the nearest base plate (3 or 4) and the nut 8 located on the same end.

[0050] For example, the fastening mechanism accommodates a spring washer 9, such as a Belleville washer. The spring washer 9 is received on the end of the tie rod 7.

[0051] More precisely, the spring washer 9 is positioned on each tie rod 7 on the outer portion of the tie rod 7 as it passes the nearest base plate (3 or 4).

[0052] Therefore, the described fixing means allow the electrolytic apparatus stack 1 to cope with variations in thermal expansion and / or mechanical stress, particularly external to and internal to the electrolytic apparatus stack 1, such as the pressure inside the electrolytic apparatus stack 1.

[0053] Furthermore, in this case, all electrolysis cells 10 in the electrolysis apparatus stack 1 are identical to one another, so that the following description of electrolysis cell 10 can also be applied to the descriptions of other electrolysis cells 10.

[0054] Such an electrolytic cell 10 houses a central membrane 11, which is formed by two electrodes 12a and 12b (anode and cathode, respectively), which are themselves formed by two flow field materials 16, and as a result, these are formed by two bipolar plates 14. Furthermore, the electrolytic cell 10 also houses a gasket 13 (whose presence has already been described above) compressed between the two bipolar plates 14 of the electrolytic cell 10.

[0055] Since the membrane 11, flow field material 16, and electrodes 12a and 12b are known in the prior art, further detailed explanations of them will be omitted here.

[0056] Since the two bipolar plates 14 of the electrolysis cell 10 are identical to each other, the following description of the bipolar plate 14 is also applicable to the other bipolar plate 14 of the same electrolysis cell 10. The bipolar plate 14 is made of a material capable of withstanding the corrosive environment that is common inside the electrolysis cell 10.

[0057] The bipolar plate 14 is, for example, nickel-based and manufactured from, for example, nickel or nickel alloy carbon steel.

[0058] The bipolar plate 14 is further configured to have two main faces: a first main face facing inward towards the electrolysis cell 10 and a second main face facing outward towards the electrolysis cell 10.

[0059] In the following, please understand that the bipolar plate 14 is asymmetrical (within a symmetrical plane passing through the center of the bipolar plate in question). As a result, within the same electrolysis cell 10, the first face of the described bipolar plate 14 is located on the opposite side of the second face of another bipolar plate 14 that is identical to the one described. Within block 2, all bipolar plates 14 are oriented in the same manner.

[0060] In the following, the X and Y axes are defined as forming a plane on which one of the main faces of the bipolar plate 14 extends, and the Z axis is defined as being perpendicular to the XY plane.

[0061] When the bipolar plate 14 is in a fixed position within the electrolysis cell 10, which itself is in a fixed position within the electrolysis apparatus stack 1, the Z-axis here coincides with the general direction A.

[0062] The thickness of the bipolar plate 14 (along the Z-axis) is less than its other dimensions.

[0063] The bipolar plate 14 is configured to have a cross-section (within the XY plane) with a specific geometric shape (square, rectangular, disc-shaped, etc.). In this case, the bipolar plate 14 has a disc-shaped cross-section.

[0064] The outer boundary of the bipolar plate 14 is defined by zone 1 21, zone 22, and zone 3 23.

[0065] The first zone 21 here extends around the entire perimeter of at least one of the main faces of the bipolar plate 14. Thus, the first zone 21 is a ring that forms the outer perimeter of the main face.

[0066] The first zone 21 allows for improved strength of the bipolar plate 14 against the internal pressures common within the electrolysis stack 1, and also improves the sealing of the electrolysis cell 10 in relation to the outside of the electrolysis stack 1. Specifically, the first zone 21 allows for reinforcement of the strength of the bipolar plate 14 against radial pressure loads acting particularly on the bipolar plate 14 (when the electrolysis cell 10 is placed within the electrolysis stack 1). For example, the first zone 21 is dimensionally set to satisfy standards applicable to pressurized containers, such as standard PED2014 / 68 / EU.

[0067] The first zone 21 is preferably textured. For example, the first zone 21 has grooves, stripes, irregularities, a roughened appearance, etc., on at least one of the main faces of the bipolar plate 14, and preferably on both main faces of the bipolar plate 14.

[0068] Conversely, the circular edges of the bipolar plate 14 (i.e., the surfaces connecting the two main faces of the bipolar plate 14) are very smooth, i.e., not textured.

[0069] Furthermore, the second zone 22 extends circumferentially, bordering the first zone 21 outward. The second zone 22 is coaxial with the first zone 21.

[0070] The second zone 22 extends around the entire perimeter of at least one of the main faces of the bipolar plate 14. Thus, the second zone 22 is a ring.

[0071] Zone 22 is smooth, meaning it is not textured.

[0072] This second zone 22 is positioned around the electrolyte supply channel and the channel for releasing the gaseous product obtained as a result of electrolysis.

[0073] This second zone 22 has a smaller thickness than the first zone (in this case, the thickness is considered along the Z axis). For example, the bipolar plate 14 is configured to have at least one shoulder between the first zone 21 and the second zone 22. Preferably, the bipolar plate 14 is configured to have two shoulders between the first zone 21 and the second zone 22. These two shoulders are identical here (as can be observed in Figure 3a) and are formed on the two main faces of the bipolar plate 14. Thus, the bipolar plate 14 is symmetrical within its first zone 21 and its second zone 22 in a central plane of symmetry parallel to axes X and Y.

[0074] The narrowing between the first zone 21 and the second zone 22 allows for the creation of different sealings between the two zones.

[0075] Furthermore, the third zone 23 extends circumferentially, bordering the second zone 22 outward. The third zone 23 is coaxial with the second zone 22.

[0076] Zone 3 23 extends here around the entire perimeter of the bipolar plate 14. Zone 3 23 is a ring.

[0077] This third zone 23 has a smaller thickness than the second zone 22 (in this case, the thickness is considered along the Z-axis). For example, the bipolar plate 14 is configured to have at least one shoulder portion between the second zone 22 and the third zone 23.

[0078] Preferably, the bipolar plate 14 is configured to have a single shoulder between the second zone 22 and the third zone 23. This shoulder is formed on the first main face of the bipolar plate 14, i.e., the one facing the interior of the electrolysis cell 10. This shoulder allows for the accommodation of the membrane 11.

[0079] Preferably, the second zone 22 and the third zone 23 extend as continuations of each other on the second main face of the bipolar plate 14.

[0080] Therefore, there is no shoulder area between the second zone 22 and the third zone 23 on the second main face.

[0081] Therefore, it should be understood that the second face of the bipolar plate 14 does not have such a shoulder, so as the second faces of the other bipolar plates 14 of the electrolysis cell 10 in question do not have such a shoulder. Accordingly, the membrane 11 is positioned between the two bipolar plates 14 so as to be contained only within the shoulder of one of the two bipolar plates 14.

[0082] Therefore, the bipolar plate 14 is asymmetrical within a symmetrical central plane parallel to the X and Y axes when considering the three aforementioned zones (as can be observed more clearly in Figures 3a, 3b, and 3c).

[0083] The third zone 23 is entirely smooth (i.e., untextured), partially smooth, or entirely textured. Preferably, the third zone 23 is textured on the first main face of the bipolar plate 14. This facilitates the retention of the membrane in place. On the first main face, for example, the third zone 23 may have grooves, stripes, irregularities, a roughened appearance, etc.

[0084] Preferably, the third zone 23 is smooth on the second main face of the bipolar plate 14.

[0085] Therefore, the thickness of the bipolar plate 14 (along the Z-axis) gradually decreases on the shoulder, not only at the junction between the first and second zones 21 and 22, but also between the second zone 22 and the third zone 23. Consequently, the bipolar plate 14 is thicker in the first zone 21 than in the second zone 22, and thicker in the second zone than in the third zone 23.

[0086] The first zone 21, the second zone 22, and the third zone 23 work together to form a color 25. Thus, the color 25 forms the circumferential perimeter of the bipolar plate 14.

[0087] Furthermore, the central portion 24 of the bipolar plate 14 extends outward, with its boundary defined by the third zone 23. The central portion 24 is coaxial with the third zone 23.

[0088] The central section 24 is solid. Therefore, the central section 24 forms a circular platform.

[0089] This central portion 24 has a smaller thickness than the third zone 23 (in this case, the thickness is considered along the Z-axis).

[0090] For example, the bipolar plate 14 is configured to have at least one shoulder portion between the third zone 23 and the central portion 24. Preferably, the bipolar plate 14 is configured to have two shoulder portions between the third zone 23 and the central portion 24. These two shoulder portions are identical and are formed on the two main faces of the bipolar plate 14.

[0091] The central portion 24 may optionally have at least one shoulder portion such that its thickness (in this case, the thickness is considered along the Z-axis) narrows in the direction of the center of the bipolar plate 14.

[0092] Therefore, the central portion 24 is the thinnest part of the bipolar plate 14 (in this case, the thickness is considered along the Z-axis).

[0093] The central portion 24 may be smooth or textured.

[0094] The central portion 24 functions as a current collector and transmits current to the flow field material 16 located on both sides of this central portion 24.

[0095] Furthermore, the bipolar plate 14 contains conduits 15 that pass through it completely. These conduits 15 are dedicated to supplying the electrolyte solution and releasing the electrolysis products.

[0096] For example, the bipolar plate 14 contains 3 to 6 conduits. The conduits are, for example, linked 2x2, in which case pairs of two conduits are uniformly distributed around the bipolar plate 14. In this example, the bipolar plate 14 contains a pair of conduits 15 for electrolyte supply, a first conduit 15 for releasing a first electrolysis product (a biphasic mixture of electrolyte and dioxygen gas), and a second conduit 15 for releasing a second electrolysis product (a biphasic mixture of electrolyte and dihydrogen gas).

[0097] For example, at least one of the conduits 15 is formed within the second zone 22. In this case, all of the conduits 15 are formed within the second zone 22.

[0098] The conduit 15 can have a circular, elliptical, or other cross-sectional shape, or a different shape. For example, at least one of the conduits 15 has an elliptical cross-section. The conduit 15 is mounted in the internal volume of the electrolysis cell 10 by radial grooves / counters extending from the conduit 15 in zone 22 to the central portion 24.

[0099] In reality, the role of the central portion 24 is not to withstand large pressure forces, as opposed to the collar 25. Therefore, the central portion 24 primarily serves as a support for the stacked components within the electrolysis cell 10, namely the flow field material 16, electrodes 12a and 12b, and the membrane 11. Thus, the force is equal on both faces of the central portion 24.

[0100] As a result, the bipolar plate 14 has a specific shape. The thickness of each of the aforementioned zones varies between them by a fraction of a millimeter to several millimeters. Furthermore, the thickness of the aforementioned zones can also change under the effect of thermal expansion of the bipolar plate 14 (this variability in the thickness of each zone is also due to thermal expansion changing from zone to zone).

[0101] As described above, the two bipolar plates 14 compress the gasket 13 between them within the electrolysis cell 10.

[0102] Note that within the electrolysis apparatus stack 1, all bipolar plates 14 are separated into a 2x2 configuration by gaskets 13 (because each bipolar plate 14 functions as a cathode for one electrolysis cell 10 and as an anode for another directly adjacent electrolysis cell 10).

[0103] Advantageously, the two bipolar plates 14 compress a single gasket 13 between them.

[0104] Advantageously, all gaskets 13 in the electrolytic cell 10 within block 2 are identical such that the subsequent description of one gasket 13 is applicable to the other gaskets 13 in the other electrolytic cells 10.

[0105] The main functions of the gasket 13 are: i) ensuring the sealing of each electrolysis cell 10 in relation to the outside of the electrolysis apparatus stack 1; ii) ensuring the sealing of the channel that carries one gas produced in block 2 in relation to the channel that carries another gas produced in block 2; iii) ensuring the sealing of the chambers that are the sites of the electrolysis reactions in which the two aforementioned gases are produced, as well as the sealing in relation to the channel mentioned above, for their isolation from one another; iv) functioning as an electrical insulating layer between two adjacent bipolar plates 14; and v) defining the thickness to which the electrolysis cell 10 is compressed along the Z direction.

[0106] Preferably, the gasket 13 is configured to have a square or rectangular cross-section (within the cross-sectional plane).

[0107] Therefore, gasket 13 is referred to as a "flat gasket."

[0108] Preferably, the gasket 13 is configured in a manner that corresponds to the shape of the collar 25 of the associated bipolar plate 14.

[0109] In this case, the gasket 13 is configured as a ring, and the associated bipolar plate is in the form of a disc.

[0110] Note that the gasket 13 is perforated with multiple holes.

[0111] This ensures the supply of fluid to block 2 and the release of fluid from block 2 to the outside. For example, the holes formed within gasket 13 correspond to those generated within zone 22 of bipolar plate 14.

[0112] The gasket 13 is configured to have as constant a diameter (of its cross-section) as possible on all of its inner and outer circumference and / or as constant a thickness (along the Z-axis) as possible on all of its segments (as well as from one gasket to another).

[0113] This makes it possible to improve the effectiveness of the electrolysis cell 10 of the electrolysis apparatus stack 1.

[0114] Specifically, this allows the gasket 13 to have faces that are as parallel as possible to each other and to the main faces of the opposite bipolar plates 14.

[0115] This also allows for improved sealing of the entire assembly.

[0116] The dimensional tolerance of the gasket 13 will depend on its intended application (for example, the tolerance is + / - 0.1 millimeters in thickness). As described above and can be observed more clearly in Figure 3c, the gasket 13 is compressed between two adjacent bipolar plates 14, and more precisely between the two outer boundary lines of the opposite main face of the bipolar plate 14, and more precisely between the two opposite collars 25 of the bipolar plate 14.

[0117] Due to its outer boundary and particularly the specific shape of the bipolar plate 14 in its collar 25, the bipolar plate 14 compresses the gasket 13, thereby deforming the gasket 13 so as to define and characterize its boundaries within three distinct portions.

[0118] Conversely, the gasket 13 is not compressed between the central portions 24 of the two bipolar plates 14.

[0119] The diameter of the gasket 13 (in cross-section) is such that the gasket 13 extends from the side edge of the bipolar plate 14 in the mounting area between the third zone 23 and the central portion 24, while (preferably protruding beyond the third zone 23).

[0120] Therefore, each part of the gasket 13 performs a separate sealing function and is characterized by a specific level of compression, in which case the level of compression changes from one part to another. The physical and mechanical result is a variable thickness reduction of the joint 13 depending on the part in question.

[0121] Therefore, when the gasket 13 is in a neutral state, it has a conventional annular shape and a substantially uniform initial thickness.

[0122] When the gasket 13 is compressed between the two bipolar plates 14, - Between the first zones 21 of the two bipolar plates 14, the gasket 13 has a textured corresponding first portion, for the reason that this matches the shape of the first zone 21. - Between the second zone 22 of the two bipolar plates 14, the gasket 13 has a corresponding smooth second portion, in which case the gasket 13 also has a greater thickness than that of its first portion. - Between the third zone 23 of the two bipolar plates 14 and the membrane 11, the gasket 13 has a corresponding smooth and / or grooved third portion.

[0123] In its first part, the gasket 13 is compressed directly between the two first zones 21 (without the involvement of intermediate components).

[0124] In its second part, the gasket 13 is compressed directly between the two second zones 22 (without the involvement of an intermediate component).

[0125] Within the third portion, conversely, the gasket 13 is not directly compressed between the two third zones 23. This is because the membrane 11 is also present within these two third zones 23. Conversely, the gasket 13 is directly compressed on one upper part of its face by one of the third zones 23 and directly compressed on the other upper part of its face by the membrane 11, which in turn is directly compressed on the other side by the third zone 23 of the bipolar plate 14.

[0126] As a result, within its third portion, the gasket 13 has substantially less thickness than that of its second portion, and in this case, the membrane 11 fills the remaining space between the two third zones 23. This results in sealing of the membrane 11.

[0127] Therefore, the gasket 13 is distributed across its entire height (along the X-axis) between its three parts and thus between the three zones of the collar 25.

[0128] As a result, the portion of the electrolysis cell 10 located in the first zone 21 of the two bipolar plates 14 and in the first portion of the gasket 13 prevents the electrolyte solution or gas from detaching from the electrolysis device stack 1, or in other words, it is dedicated to ensuring the sealing of the electrolysis cell 10 in relation to the external environment. For example, this is measured when the sealing is measured using helium gas. -3Sealing density of milligrams / meter / second (mg / (m*s)) or higher and preferably 10 -4 We guarantee sealing of mg / (m*s) or higher.

[0129] This first part is characterized by the presence of texture on the bipolar plate 14, in which the gasket 13 deforms inside. By deforming, the gasket 13 can specifically fill the hollow in the first part of the bipolar plate 14, thereby reinforcing the sealing of the electrolysis cell 10. This is because these textures constitute an additional barrier to any gases and other substances present that would otherwise attempt to secure their passage to the outside of the electrolysis apparatus stack 1. The presence of textures also functions to promote friction between the electrolysis cells 10 and, therefore, to promote self-retention of the multiple electrolysis cells 10 stacked to form block 2. This advantage is reinforced when block 2 is horizontal during operation.

[0130] For example, the compression of the gasket 13 is such that the gasket 13 reaches a maximum thickness of 94%, preferably 78%, and more preferably 75% of its initial thickness within the first portion (along the Z-axis) (when the gasket 13 is in its neutral, flat state on a plain surface without external constraints). The initial thickness is, for example, equal to 3.0 millimeters or more. Preferably, this initial thickness does not exceed 3.5 millimeters. As one variation, a thinner gasket may be used.

[0131] The second portion of the electrolysis cell 10, located in the second zone 22 of the two bipolar plates 14 and in the second portion of the gasket 13, makes it possible to prevent exchange between channels that transport dihydrogen and dioxygen within the electrolysis cell 10 or from the electrolysis cell 10 itself (starting from the second zone 23 and the central portion 24) toward the channels.

[0132] For example, the compression of the gasket 13 is such that the gasket 13 reaches a thickness of 92-97% of its initial thickness, preferably 92% of its initial thickness, within the second portion (along the Z-axis) (when the gasket 13 is in its neutral, flat state on a plain surface without external constraints). In all cases, the gasket 13 is less compressed and therefore has a greater thickness than within the first portion.

[0133] The widening of the gasket 13 between the first zone 21 and the second zone 22 allows for the creation of different seals between the first zone 21 and the second zone 22. In any case, the seal between the first zone 21 and the second zone is of high quality.

[0134] The third portion of the electrolysis cell 10, located in the third zone 23 of the two bipolar plates 14 and in the third portion of the gasket 13, is capable of receiving the membrane 11, as described above.

[0135] Therefore, this third part ensures sealing between the anode and cathode components of the electrolysis cell 10.

[0136] Therefore, it should be noted that not only the membrane 11 but also the gasket 13 is subsequently compressed between the two bipolar plates 14 within this third portion, and thus the gasket 13 is superimposed on the membrane 11 on this portion of the electrolysis cell 10.

[0137] This ensures very good sealing around the membrane 11 along its boundary and in the direction of the supply and fluid discharge conduits.

[0138] Therefore, the third portion of the gasket 13 defines a third compression zone intended to ensure the retention of the membrane and its sealing along its boundary.

[0139] For example, the compression of the gasket 13 is such that the gasket 13 reaches a thickness of 86% to 92% of its initial thickness, preferably 88% to 92% of its initial thickness, and more preferably 90% of its initial thickness, within the third portion (along the Z-axis) (when the gasket 13 is in its neutral, flat state on a plain surface without external constraints).

[0140] In another embodiment, the gasket 13 is manufactured from, for example, a homopolymer material or copolymer material such as a thermoplastic material.

[0141] For example, the gasket 13 is made of a material of the type polytetrafluoroethylene or polytetrafluoroethene (commonly abbreviated as PTFE or more widely known by the trade name Teflon®) or FKM (more widely known by the trade name Viton®).

[0142] Preferably, the material is composed of, or based on, polytetrafluoroethylene or polytetrafluoroethene, complemented by at least one filler. For example, the filler is glass fiber.

[0143] For example, the material is reinforced polytetrafluoroethylene. For example, the reinforced polytetrafluoroethylene is polytetrafluoroethylene reinforced with glass fibers, or the reinforced polytetrafluoroethene is polytetrafluoroethene reinforced with carbon fibers.

[0144] The properties of the gasket 13 described are defined below. - Even at high operating temperatures (typically around 90-95°C), the material behaves well and maintains its good mechanical properties, especially over long periods at the operating temperature of the electrolysis cell 10. - In particular, resistance to the corrosive environment inside the electrolysis cell 10 over long periods of time. - Good sealing properties - Good electrical insulation properties (provided by good electrical resistance) both at operating temperatures and in contact with electrolyte solutions. - Good lifespan of electrolytic apparatus stack 1 of electrolytic cell 10, tolerated by almost non-existent creep. - However, a slight creep behavior is necessary to optimally match the geometric characteristics of zone 21 on which gasket 13 is seated. - Thickness uniformity (along the Z-axis)

[0145] According to one option, the end gasket positioned between the first distribution plate 5 and the first base plate 3 is made of the same material as the gasket 13 of the electrolysis cell 3 described immediately above. The end gasket is, for example, identical to the gasket 13. The gasket is optionally manufactured from a homopolymer or copolymer material, such as a thermoplastic material.

[0146] According to one option, the layer of electrical insulating material between the first base plate 3 and the first distribution plate 5 is made of the same material as the end gasket positioned between the first distribution plate 5 and the first base plate. According to another option, the layer of electrical insulating material between the first base plate 3 and the first distribution plate 5 is made of the same material as the gasket 13. The layer is optionally manufactured from a homopolymer or copolymer material, such as a thermoplastic material.

[0147] According to one option, the end gasket positioned between the second distribution plate 6 and the second base plate 4 is made of the same material as the gasket 13 of the electrolysis cell 10 described immediately above. The end gasket is, for example, identical to the gasket 13. The end gasket is optionally manufactured from a homopolymer or copolymer material, such as a thermoplastic material.

[0148] According to one option, the patch on the inner face of the first distribution plate 5 is a layer of material added directly onto the first distribution plate 5, or is formed by the deposition of powders such as ethylene chlorotrifluoroethylene, such as fluoropolymers, and especially those manufactured by SOLVAY under the Halar brand.

[0149] Therefore, the electrolytic cell 10 described has very good sealing due to specific compression of the gasket 13 between the bipolar plates 14.

[0150] It should be further noted that the electrolysis cell 10 is sealed by utilizing a single gasket 13, specifically by three zones having different sealing and compression characteristics. The use of a single gasket 13 manufactured from plastic (rather than elastomer as in the prior art) further allows for improved sealing of the electrolysis apparatus stack.

[0151] This is because the gasket 13 provides good resistance to the corrosive environment common inside the electrolysis apparatus stack 1, and it continues to do so even over long periods of time.

[0152] Therefore, the gasket 13 is made of a hard material that can withstand the large mechanical compressions to which the electrolysis apparatus stack 1 is subjected.

[0153] Furthermore, the electrolysis apparatus stack 1 has intermediate plates, collectively denoted by 30, which are clamped within the stack of elements forming block 2. Each intermediate plate 30 has an annular outer peripheral portion 31 and a disc-shaped central portion 32. The intermediate plate 30 has a thickness on which at least two electrolyte supply conduits, a first conduit for releasing a first electrolysis product, and a second conduit for releasing a second electrolysis product, all denoted by reference numeral 33, are formed, and these are integrated with the supply network, the first release network, and the second release network of the electrolysis apparatus stack 1. The thickness of the intermediate plate 30 has a value of several millimeters to several tens of millimeters, preferably 50 to 70 mm. Each of the conduits 33 formed within the intermediate plate 30 is open near the main face opposite the outer peripheral portion 31 through an inlet orifice and an outlet orifice, and has a length between these two orifices exceeding the thickness of the intermediate plate 30. Each conduit 33 has a bent segment 34 that connects inlet and outlet orifices to each other, extending within and preferably near the center of the central portion 32 of the intermediate plate 30. Thus, the bent segment 34 has a first end that extends parallel to the main face of the intermediate plate 30 and is connected to each other by bending, and on the opposite side, it has a U-shape with two branches, each forming one of the orifices on the main face of the intermediate plate 30. The intermediate plate 30 is manufactured from a conductive material by additive manufacturing, molding (e.g., by using a sliding core mold), forging and subsequent machining, etc.

[0154] The intermediate plates 30 are distributed within block 2 such that two intermediate plates 30 are positioned on both sides of the plurality of electrolysis cells 10. The plurality of electrolysis cells 10 preferably have 20 to 50 electrolysis cells 10.

[0155] The sealing between each intermediate plate 30 and the surrounding electrolytic cell 10 is ensured, for example, by two gaskets identical to gasket 13.

[0156] The following describes how to assemble the electrolysis apparatus stack 1.

[0157] According to the first step, the subassemblies are constructed individually, in this case, by assembling two flow field materials 16 and two electrodes 12a and 12b on both sides of the bipolar plate 14. Strictly speaking, each subassembly constitutes two mounted electrolytic half-cells 10.

[0158] In the second step, the subassemblies are stacked in a continuous manner, separated from each other by membranes 11 and gaskets 13, to form the electrolytic cells 10 electrically connected in series. The last electrolytic cell 10 at one end of block 2 is covered by a second distribution plate 6, which is itself covered by a second base plate 4, and the last electrolytic cell 10 at the other end of block 2 is covered by a first distribution plate 5, which is itself covered by a first base plate 3, thereby defining the boundary of the electrolytic apparatus stack 1. An intermediate plate 30 is periodically interposed between the two continuous electrolytic cells 10. During this operation, it should be noted that the conduits 33 and 15 are in communication with each other to form the supply network, the first discharge network, and the second discharge network.

[0159] In the third step, the newly assembled electrolysis apparatus stack 1 is positioned under pressure by utilizing the tie rod 7, nut 8, and spring washer 9.

[0160] Such a configuration, having thick distribution plates 5 and 6 and a thin planar bipolar plate 14, allows for uniformity of current within all electrolytic cells 10 of the electrolytic apparatus stack 1, where the voltages differ across the terminals of each electrolytic cell 10 and the current is connected to only one or more points around each distribution plate 5 and 6.

[0161] Furthermore, the bipolar plates 14 are very parallel to each other within the block 2 due to their specific shape and the good clamping of their respective gaskets 13. This, in some cases, further improves the uniformity of the current within all electrolytic cells.

[0162] The assembly method, ideally, specifically, each gasket 13, - It deforms according to the shape imposed by the bipolar plate 14 that clamps itself. - Pressed into the texture of the first zone 21 to fill the texture, - Intentionally and prematurely aging the materials that make up the product. - Remove the constituent plastics that make up the structure to the greatest extent possible. - To cause the material to enter an elastic behavior range (centered on the operating point of the electrolysis device stack 1), - Achieves the desired tightening value, thereby combining not only the required sealing but also electrical contact between various components, and thereby enables the achievement of the expected energy performance. This would mean allowing it.

[0163] The rated operating point of the electrolysis apparatus stack 1 is, for example, 85°C under 3 megapascals.

[0164] Naturally, the present invention is not limited to the embodiments described and includes any modifications that fall within the field of the invention as defined by the claims.

[0165] One or more end gaskets may be different from gasket 13.

[0166] The electrolysis apparatus stack 1 may be assembled in a manner different from that described above.

[0167] The electrolysis apparatus stack 1 may be used horizontally, vertically, or in any other position. The electrolysis apparatus stack 1 may be assembled horizontally, vertically, or in any other position. Preferably, the electrolysis apparatus stack 1 will be assembled vertically and used horizontally.

[0168] Only one conduit 33 associated with supplying the electrolyte solution and one conduit 33 associated with releasing the respective electrolysis products may be present. However, for redundancy in case one of the conduits 33 becomes blocked, it would be preferable to have two conduits 33 associated with supplying the electrolyte solution and / or two conduits 33 associated with releasing the respective electrolysis products. In general, the distribution plates 5 and 6 may accommodate only one conduit 33 opening at each end of the individual main faces of the distribution plates 5 and 6.

[0169] Similarly, for reasons of redundancy, it would be preferable to have two grooves associated with each end of each conduit 33.

[0170] The various conduits 33 do not have to be identical to one another.

[0171] The various grooves do not have to be identical to one another.

[0172] The two distribution plates 5 and 6, each associated with one end of block 2, may not be identical to each other but different, as described above.

[0173] Distribution plates 5 and 6 can accommodate only a single reinforcement, rather than two as shown in the figure.

[0174] The distribution plates 5 and 6 can accommodate at least one conduit 33 that does not open at at least one of its ends on the outer boundary line of the associated main face (and does not open in, for example, within the central zone of the main face, such as possibly within reinforcement present on the main face).

[0175] For example, the distribution plates 5 and 6 may accommodate at least one conduit 33 opening at at least one of its ends within the reinforcement of the distribution plates 5 and 6. Optionally, the conduit 33 may open at at least one of its ends at a position sufficiently close to the outer boundary line of one of the main faces to allow for complete or near-complete discharge (discharge of liquids and / or gases) present in the space between the distribution plates 5 and 6 in question and the base plates 3 and 4 on the opposite side. Optionally, the conduit 33 may be formed to open at a first end within the reinforcement of the first main face of the distribution plates 5 and 6 and at a second end within the reinforcement of the second main face of the distribution plates 5 and 6 to establish communication between the two reinforcements.

[0176] The electrolysis apparatus stack 1 may have three electrodes, namely two end cathodes and one central anode.

[0177] One or more of the bipolar plates 14 may be configured to have a conduit 15 with a folded section for generating one or more intermediate plates 30 from this or these bipolar plates 14. In this case, all or some of the conduits 15 formed within the intermediate plate 30 have a length exceeding the thickness of the bipolar plate 14.

[0178] As another variation, one or two of the one or more intermediate plates 30 may be formed by one or more of the one or more distribution plates 5, 6 that extend between the end plates 3, 4 and the adjacent electrolysis cell 10. In this case, the conduit 15 formed within the distribution plates 5, 6 has a length exceeding the thickness of the distribution plates 5, 6.

[0179] The spring washer 9 may be located at both ends of the tie rod or at a single end thereof, and / or may be replaced by any elastic compression member.

[0180] The U-shaped segment does not need to extend all the way to the center of the intermediate plate.

Claims

1. An electrolysis apparatus stack (1) having two base plates (3, 4) that clamp a stack (2) of elements housing electrolysis cells (10), wherein each electrolysis cell (10) has at least one electrolyte supply conduit communicating from one electrolysis cell (10) to another, a first conduit for releasing the first electrolysis product, and a second conduit for releasing the second electrolysis product (15), in order to form an electrolyte supply network, a first network for releasing a first electrolysis product, and a second network for releasing a second electrolysis product along the electrolysis apparatus stack (1) within the electrolysis apparatus stack (1), The electrolysis apparatus stack (1) has at least one intermediate plate (30) clamped within the stack (2) of elements, the intermediate plate (30) having a thickness on which at least one electrolyte supply conduit, a first conduit for releasing the first electrolysis product, and a second conduit (33) for releasing the second electrolysis product are formed, these being individually integrated with the supply network, the first release network, and the second release network, and Each of these conduits (33) formed within the intermediate plate (30) has a length exceeding the thickness of the intermediate plate (30) and has a bent segment (34) connecting an inlet orifice on the first main face of the intermediate plate and an outlet orifice on the second main face of the intermediate plate, the bent segment having a first end extending parallel to the main face of the intermediate plate (30) and joined to one another by bending, and on the opposite side having a U-shape with two branches, each having an end that forms one of the orifices on the main face of the intermediate plate (30). An electrolysis apparatus stack characterized by the following features.

2. The electrolysis apparatus stack (1) according to claim 1, characterized in that it has at least two intermediate plates (30) arranged on both sides of the plurality of electrolysis cells (10).

3. The electrolysis apparatus stack (1) according to claim 2, wherein the plurality of electrolysis cells (10) have 20 to 50 electrolysis cells (10).

4. An electrolysis apparatus stack (1) according to any one of claims 1 to 3, characterized in that the intermediate plate (30) is a bipolar plate (14) of one of the electrolysis cells (10).

5. An electrolysis apparatus stack (1) according to any one of claims 1 to 4, characterized in that the intermediate plate (30) is a current distribution plate (5, 6) extending between the end plates (3, 4) and the adjacent electrolysis cell (10).

6. An electrolysis apparatus stack (1) according to any one of claims 1 to 5, characterized in that the stack (2) of the elements is configured in a vertical or horizontal direction.

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