Tank core unit of PEM water electrolyser, assembly method of cell core unit and PEM water electrolyser

Abstract

The invention discloses a cell core unit of a PEM water electrolysis cell, an assembling method of the cell core unit and the PEM water electrolysis cell. The side surface of the reaction area of the groove core unit is covered with a pure equal partition plate, and the outer side is only provided with a single frame; the upper surface of the frame is provided with a cathode micro-channel on the outer side of the reaction area through hole through a plurality of cathode sealing surfaces in the vertical direction, and the lower surface of the frame is provided with an anode micro-channel on the outer side of the reaction area through hole through a plurality of anode sealing surfaces in the horizontal direction; an inner ring sinking table is arranged between the anode micro-channel and the reaction area through hole; a whole ring of membrane electrode sealing surface is arranged on the inner side of the inner ring sinking table; the membrane electrode and the anode diffusion layer are arranged below the reaction area through hole and close to the inner side of the inner ring sinking platform; the upper layer of the anode diffusion layer tightly attached to the membrane electrode is a titanium felt with a compacted edge, and the lower layer is a water-permeable titanium mesh. The thickness of the groove core unit is effectively reduced, the number of parts is reduced, meanwhile, the area of the membrane electrode is reduced, and the risk that the membrane electrode made of a soft material is independently assembled and misplaced is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of water electrolyzers, in particular to a cell core unit of a PEM water electrolyzer, an assembly method thereof and the PEM water electrolyzer. Background Art

[0002] The most critical component in PEM water electrolysis hydrogen production technology is the electrolyzer. Usually, the electrolyzer core unit for water electrolysis hydrogen production consists of a plate or a separator, a sealing film, a resin frame, a diffusion layer assembly of the cathode and anode, and a membrane electrode. The resin frame defines the reaction chamber area of ​​the electrolyzer, and the plate or separator defines the gas produced by the reaction of the cathode and anode on both sides.

[0003] For example, the invention patent applications with publication numbers CN 113755855 A, CN 108796539 A, and CN 117904650 A, currently the core units of PEM electrolyzers are provided with two frames, cathode and anode, and the thickness of a single core section is more than 4 mm after adding the partition plate. Further thinning and optimization of the thickness is one of the design goals of the next generation of electrolyzers. At the same time, the membrane electrode under the existing structure covers the entire flow channel area, and the coverage area is very large. In the field of electrolyzers, the membrane electrode is the most expensive part. The excessive area of ​​the membrane electrode will result in an excessively high unit price of the electrolyzer product, which is not conducive to the promotion and application of the electrolyzer product. In addition, the core unit of the conventional structure usually has two baffles, and the large number of single-section parts makes the assembly process of the core unit more cumbersome and the quality controllability is poor.

[0004] The invention patent application with the publication number CN118563348A discloses an electrolyzer sealing assembly, wherein the electrolyzer sealing assembly includes an electrode frame and an outer seal; the two end faces of the inner frame hole are divided into the anode side and the cathode side, the anode side is concave around the periphery of the inner frame hole to form a limiting step surface for the membrane electrode assembly to be built in, and the electrode frame is also provided with a water inlet and outlet hole and a hydrogen outlet hole on the outside of the limiting step surface, a first guide groove is provided between the water inlet and outlet hole and the limiting step surface on the anode side, and a second guide groove is provided between the hydrogen outlet hole and the inner frame hole on the cathode side; an outer seal is provided between the anode side and the bipolar plate and between the cathode side and the bipolar plate. Although this technical solution provides an electrolyzer with a single pole frame, a membrane electrode frame is introduced to realize the integration of the membrane electrode and the anode diffusion layer. The risk of hydrogen leakage is high if there are many types of integrated parts; in addition, the structure is sealed by pressure, and the flow resistance of water increases after the anode diffusion layer is pressurized, which will lead to a decrease in electrolysis efficiency. Summary of the invention

[0005] In view of the above-mentioned defects in the prior art, the present invention provides a cell core unit of a PEM water electrolyzer, an assembly method thereof and a PEM water electrolyzer, which adopts a single frame design to effectively reduce the thickness of the cell core unit; at the same time, titanium felt with compacted edges is used for pressure sealing, which effectively reduces the area of ​​the membrane electrode while ensuring the sealing of the membrane electrode.

[0006] To achieve the above-mentioned purpose, in a first aspect, the present invention provides a cell core unit of a PEM water electrolyzer, comprising a cathode diffusion layer, a membrane electrode, and an anode diffusion layer; the membrane electrode is arranged between the cathode diffusion layer and the anode diffusion layer as a reaction zone; the diameter of the cathode diffusion layer is smaller than the diameter of the membrane electrode; the side of the reaction zone is covered with a flat partition plate, and a single-layer frame is arranged on the outside; the upper and lower sides of the membrane electrode are the cathode and anode of the cell core unit respectively;

[0007] A reaction zone through hole is formed in the center of the frame, and a first through hole as a hydrogen channel and a second through hole as a water channel are respectively formed outside the reaction zone through hole, vertically and horizontally.

[0008] The upper surface of the frame is provided with cathode microchannels at the outer side of the reaction zone through hole and in the vertical direction through a plurality of cathode sealing surfaces, and the lower surface is provided with anode microchannels at the outer side of the reaction zone through hole and in the horizontal direction through a plurality of anode sealing surfaces; an inner circle sink is provided between the anode microchannel and the reaction zone through hole; a full circle of membrane electrode sealing surfaces is provided on the inner side of the inner circle sink;

[0009] The cathode diffusion layer is arranged on the upper layer of the through hole of the reaction zone, and the membrane electrode and the anode diffusion layer are arranged on the lower layer of the through hole of the reaction zone and close to the inner side of the inner circle sink. The anode diffusion layer is divided into two layers, the upper layer close to the membrane electrode is a titanium felt with compacted edges, and the lower layer is a water-permeable titanium mesh. The diameter of the membrane electrode is not greater than the diameter of the anode diffusion layer, and not less than the outer diameter of the membrane electrode sealing surface. The outer side of the reaction zone is sealed by the cathode sealing surface, the anode sealing surface and the membrane electrode sealing surface of the frame. The flat partition plate is provided with through holes corresponding to the first through hole and the second through hole, and is stacked on the outer side of the frame. The diameter of the membrane electrode is not greater than the diameter of the anode diffusion layer, and not less than the outer diameter of the membrane electrode sealing surface. There is a certain width from the inner circle sink to the reaction zone, and the end face of the membrane electrode can be as close to the membrane electrode sealing surface as possible to obtain a membrane electrode with the smallest size and reduce the material cost as much as possible.

[0010] The slot core unit of the present invention is designed with a single frame, and the cathode sealing surface of the cathode completely covers the sealing area and the flow channel area, ensuring that the generated hydrogen does not leak out and does not leak to the lower anode side, while the anode sealing surface of the anode only covers the flow channel area, ensuring that the stress of the sealing surface is uniform, and the oxygen and water on the anode side will not leak out and leak; applying sufficient pressure on the upper surface of the membrane electrode edge, the edge compacted titanium felt has a low elastic modulus, and can well absorb the extrusion of the frame ridges in the sealing area, and the reaction area can be sealed through the membrane electrode sealing surface, while the middle part of the titanium felt is water permeable, ensuring that the anode reaction area is close to the cathode reaction area, so that the current distribution of the two poles is more uniform; the anode water flow distribution area is provided with a titanium mesh support with high rigidity, and there is a microporous structure inside for water flow, which does not affect the uniformity of the water flow at this place after being pressurized; adjacent slot core units share a pure flat partition plate. These structural designs can effectively reduce the thickness of the slot core unit on the one hand, and on the other hand, the membrane electrode does not need to cover the flow channel area, reducing the area of ​​the membrane electrode and reducing the cost.

[0011] In some embodiments of the first aspect, the cathode sealing surface, the anode sealing surface and the membrane electrode sealing surface are the end surfaces of the convex ridge structure on the surface of the frame; the protruding heights of the cathode sealing surface and the anode sealing surface are 0.1~0.2 mm; and the protruding height of the membrane electrode sealing surface is 0.3~0.4 mm.

[0012] By adopting this technical solution, the frame with a ridge structure on the surface can be integrally formed by common resin materials, and the integrity of the frame is better.

[0013] Furthermore, a cathode sealing gasket is provided between the frame and the cathode diffusion layer, and the cathode sealing surface is sealed by the cathode sealing gasket; an anode sealing gasket is provided between the frame and the anode diffusion layer, and the anode sealing surface is sealed by the anode sealing gasket. With this technical solution, the addition of the sealing gasket makes the frame more sealed.

[0014] Furthermore, the cathode gasket and the anode gasket are both made of PTFE with a thickness of 0.1-0.3 mm. The gasket material is moderately soft and hard to ensure the reliability of the sealing performance of the slot core, and the consistent thickness of the two reduces the cost of coil procurement.

[0015] In other embodiments of the first aspect, the cathode sealing surface, the anode sealing surface and the membrane electrode sealing surface are rubber strip sealing surfaces bonded to the frame; the thickness of the rubber strips of the cathode sealing surface and the anode sealing surface is 0.1~0.2 mm; the thickness of the rubber strip of the membrane electrode sealing surface is 0.3~0.4 mm.

[0016] In some embodiments of the first aspect, the cathode diffusion layer is formed by bonding and stacking multiple layers of carbon paper; and the area of ​​the middle water-permeable portion of the titanium felt is consistent with the area of ​​the cathode diffusion layer.

[0017] With this technical solution, the cathode diffusion layer ensures that the thickness of the reaction area and the sealing area are the same under a certain total pressure, ensuring that the stress in different areas of the single-section slot core is in a suitable range. The anode reaction area is the same as the cathode reaction area, making the current distribution at both poles more uniform.

[0018] In a second aspect, the present invention provides a method for assembling a core unit of a PEM water electrolyzer, which is used to assemble the core unit of the PEM water electrolyzer as described above, comprising the following steps:

[0019] Step S1, assembling the membrane electrode and the anode diffusion layer to form a first assembly;

[0020] Step S2, placing the first assembly in the center;

[0021] Step S3, placing an anode seal and a frame in sequence on the outer ring of the first assembly;

[0022] Step S4, placing the cathode diffusion layer in the center;

[0023] Step S5, placing a cathode seal on the outer ring;

[0024] Step S6: Cover the entire flat partition plate (titanium plate) and apply pressure to tighten and stress-seal.

[0025] When assembling the slot core unit of the present invention, the membrane electrode and the anode diffusion layer can be integrated in advance, thereby avoiding the risk of easy misalignment when assembling the membrane electrode of soft materials separately. There is no dangerous gap between the lower surface of the membrane electrode and the anode diffusion layer, and the risk of rupture is small.

[0026] In some embodiments of the second aspect, the anode seal is an anode sealing gasket or an anode rubber sealing strip assembled at the anode sealing surface and the membrane electrode sealing surface of the frame; the cathode seal is a cathode sealing gasket or a cathode rubber sealing strip assembled at the cathode sealing surface of the frame.

[0027] The above technical solutions can be appropriately selected according to the material and assembly cost without affecting the sealing of the assembled product. The cathode and anode sealing gaskets not only ensure the sealing performance of the slot core as a whole, but also make it easy to distinguish the materials during assembly due to their different widths.

[0028] In a third aspect, the present invention also provides a PEM water electrolyzer, which comprises, from top to bottom, an upper end plate, an upper insulating plate, an upper current collecting plate, a stacked cell core unit of the PEM water electrolyzer as described above, a blind end current collecting plate, a blind end insulating plate and a blind end plate.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] (1) The slot core unit structure design of the present invention effectively reduces the thickness of the slot core unit while ensuring the sealing performance, and also reduces the number of components of the electrolytic cell, which has high industrial feasibility.

[0031] (2) The slot core unit structure design of the present invention eliminates the need for the membrane electrode to cover the flow channel area, thereby minimizing the area of ​​the membrane electrode and reducing costs.

[0032] (3) The slot core unit assembly method of the present invention integrates the membrane electrode and the anode diffusion layer in advance, avoiding the risk of misalignment when the membrane electrode made of soft materials is assembled separately. In addition, there is no dangerous gap between the lower surface of the membrane electrode and the anode diffusion layer, and the risk of rupture is low.

[0033] (4) The sealing surface of the slot core unit of the present invention is adaptable to a variety of optional technical solutions and can be appropriately selected based on the material and assembly cost without affecting the sealing of the assembled product. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The present invention and its features, appearance and advantages will become more apparent by reading the detailed description of non-limiting embodiments with reference to the following drawings. The same reference numerals indicate the same parts in all the drawings. The drawings are not drawn completely to scale, and emphasis is placed on illustrating the subject matter of the present invention.

[0035] Figure 1 A three-dimensional diagram of the overall structure of a slot core unit in one embodiment of the present invention;

[0036] Figure 2 for Figure 1 AA cross-sectional view of ;

[0037] Figure 3 for Figure 2 Enlarged view of the cross section at B in the middle;

[0038] Figure 4 A plan view of the cathode side of a frame in one embodiment of the present invention;

[0039] Figure 5 It is a plan view of the anode side of the frame in one embodiment of the present invention;

[0040] Figure 6 It is a flow chart of assembling the slot core unit in one embodiment of the present invention;

[0041] Figure 7 Schematic diagram of a three-dimensional PEM electrolyzer in one embodiment of the present invention.

[0042] Among them, 1. reaction zone through hole; 10. frame; 11. cathode sealing surface; 12. cathode microchannel; 13. first through hole; 14. second through hole; 15. anode sealing surface; 16. anode microchannel; 17. inner circle sink; 18. membrane electrode sealing surface; 21. flat separator; 22. cathode diffusion layer; 23. membrane electrode; 24. anode diffusion layer; 241. titanium felt; 242. titanium mesh; 31. cathode sealing gasket; 32. anode sealing gasket; 41. upper end plate; 42. upper insulating plate; 43. upper current collecting plate; 44. slot core unit; 45. blind end current collecting plate; 46. blind end insulating plate; 47. blind end plate. DETAILED DESCRIPTION

[0043] The structure of the present invention is further described below in conjunction with the accompanying drawings and specific embodiments, but is not intended to limit the present invention.

[0044] In the description of the present application, the terms "upper", "lower", "inside", "outside", "vertical", "horizontal", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and do not require that the present invention must be constructed and operated in a specific orientation. Therefore, they should not be understood as limitations on the present invention.

[0045] In addition, the terms "first", "second", and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first", "second", and "third" may explicitly or implicitly include one or more of the features. "Several" means two or more, unless otherwise clearly and specifically defined.

[0046] Example 1

[0047] See also Figures 1 to 5 This embodiment provides a cell core unit of a PEM water electrolyzer, comprising a cathode diffusion layer 22, a membrane electrode 23, and an anode diffusion layer 24; the membrane electrode 23 is disposed between the cathode diffusion layer 22 and the anode diffusion layer 24 as a reaction zone; the diameter of the cathode diffusion layer 22 is smaller than the diameter of the membrane electrode 23; the side of the reaction zone is covered with a flat partition plate 21, and a single-layer frame 10 is disposed on the outside; the upper and lower sides of the membrane electrode 23 are the cathode and anode of the cell core unit respectively;

[0048] A reaction zone through hole 1 is formed in the center of the frame 10, and a first through hole 13 as a hydrogen channel and a second through hole 14 as a water channel are respectively formed outside the reaction zone through hole 1, vertically and horizontally.

[0049] The upper surface of the frame 10 is provided with a cathode microchannel 12 in a vertical position outside the reaction zone through hole 1 through a plurality of cathode sealing surfaces 11, and the lower surface is provided with an anode microchannel 16 in a horizontal position outside the reaction zone through hole 1 through a plurality of anode sealing surfaces 15; an inner circle depression 17 is provided between the anode microchannel 16 and the reaction zone through hole 1; a full circle of membrane electrode sealing surface 18 is provided on the inner side of the inner circle depression 17; the inner circle depression 17 has a moderate width to ensure that the membrane electrode has sufficient sealing surface and stress.

[0050] The cathode diffusion layer 22 is arranged on the upper layer of the reaction zone through hole 1, and the membrane electrode 23 and the anode diffusion layer 24 are arranged on the lower layer of the reaction zone through hole 1, close to the inner side of the inner circle sink 17; the anode diffusion layer 24 is divided into two layers, the upper layer close to the membrane electrode 23 is a titanium felt 241 with compacted edges, and the lower layer is a water-permeable titanium mesh 242. The titanium felt 241 has a low elastic modulus, and the edges are compacted and impermeable, which can press the membrane electrode to achieve a sealing effect, and the middle part is permeable, ensuring that the anode reaction area is close to the cathode reaction area, so that the current distribution of the two poles is more uniform. The titanium mesh 242 has a high elastic modulus, and there is a microporous structure inside for water to flow, which does not affect the uniformity of the water flow at this place after being pressurized. The outside of the reaction zone is sealed by the cathode sealing surface 11, the anode sealing surface 15 and the membrane electrode sealing surface 18 of the frame 10; the pure flat partition plate 21 has through holes corresponding to the first through hole 13 and the second through hole 14, and is stacked on the outside of the frame 10. The diameter of the membrane electrode 23 is not greater than the diameter of the anode diffusion layer 24, and not less than the outer diameter of the membrane electrode sealing surface 18. There is a certain width from the inner ring sink 17 to the reaction zone, and the end face of the membrane electrode 23 can be as close to the membrane electrode sealing surface 18 as possible to obtain the smallest membrane electrode and reduce the material cost as much as possible.

[0051] The flat partition plate 21 is used as a partition part between each cell core and is made of corrosion-resistant metal material. The design of the flat partition plate ensures the conductivity and corrosion resistance of the reaction zone and increases the service life of the electrolytic cell.

[0052] It is understandable that the outer circumference of the frame 10 can be provided with several pairs of bolt fastening holes (not shown in the figure) for fastening the slot core unit according to the requirements of the fastening and sealing of the upper and lower pure flat partition plates. The pure flat partition plate here refers to a partition plate that is a flat plate without a flow channel groove.

[0053] When the cell core unit is used for water electrolysis, water enters the anode diffusion layer through the water channel and the anode microchannel 16 to undergo a reduction reaction, generating oxygen, hydrogen ions and electrons. The hydrogen ions pass through the membrane electrode layer into the cathode diffusion layer to undergo an oxidation reaction, obtaining electrons from the external circuit to generate hydrogen, which leaves through the cathode microchannel 12 and the hydrogen channel to be collected.

[0054] The slot core unit is designed with a single-layer frame. The cathode sealing surface of the cathode completely covers the sealing area and the flow channel area, ensuring that the generated hydrogen does not leak out and does not leak to the lower anode side, while the anode sealing surface of the anode only covers the flow channel area, ensuring that the stress of the sealing surface is uniform, and the oxygen and water on the anode side will not leak out and leak; sufficient pressure is applied to the upper surface of the membrane electrode edge and the edge of the titanium felt compaction, and the reaction area is sealed through the membrane electrode sealing surface. The anode diffusion layer has a larger area than the cathode diffusion layer, and the extra sealing area transmits the sealing stress by the edge of the titanium felt compaction, which not only improves the sealing strength of the membrane electrode sealing surface, but also makes the anode reaction area close to the cathode reaction area, and the current distribution of the two poles is more uniform; adjacent slot core units share a pure flat partition plate. These structural designs, on the one hand, effectively reduce the thickness of the slot core unit, and on the other hand, the membrane electrode does not need to cover the flow channel area, reducing the area of ​​the membrane electrode and reducing the cost. In addition, the components of the slot core unit include only a flat partition plate, a frame, and two gaskets or sealing rings, in addition to the cathode diffusion layer, the anode diffusion layer, and the membrane electrode. While ensuring the sealing reliability, the types and quantities of parts are greatly reduced, and the manufacturing and installation costs are low.

[0055] The cathode sealing surface 11, the anode sealing surface 15 and the membrane electrode sealing surface 18 are the end surfaces of the convex ridge structure on the surface of the frame 10; the protruding height of the cathode sealing surface 11 and the anode sealing surface 15 is 0.1~0.2mm; the protruding height of the membrane electrode sealing surface 18 is 0.3~0.4 mm. With this technical solution, the frame with a convex ridge structure on the surface can be integrally formed by a common resin material, and the integrity of the frame is better. As a further preferred technical solution, a cathode sealing gasket 31 is also provided between the frame 10 and the cathode diffusion layer 22, and the cathode sealing surface 11 is sealed by the cathode sealing gasket 31; an anode sealing gasket 32 ​​is also provided between the frame 10 and the anode diffusion layer 24, and the anode sealing surface 15 is sealed by the anode sealing gasket 32. With this technical solution, the addition of the sealing gasket makes the sealing of the frame better. Furthermore, the material of the cathode sealing gasket 31 and the anode sealing gasket 32 ​​are both PTFE, with a thickness of 0.1~0.3 mm. The sealing gasket material has moderate hardness and softness to ensure the reliability of the sealing performance of the slot core, and the consistent thickness of the two reduces the purchase cost of the coil material.

[0056] In some embodiments, the cathode diffusion layer 22 is formed by bonding and stacking multiple layers of carbon paper. With this technical solution, the cathode diffusion layer ensures that the thickness of the reaction area and the sealing area can be the same under a certain total pressure, ensuring that the stress of different areas of the single-section slot core is in a suitable range. The area of ​​the middle water-permeable part of the titanium felt 241 is consistent with the area of ​​the cathode diffusion layer 22, so that the anode reaction area is consistent with the cathode reaction area, and the current distribution of the two poles is more uniform.

[0057] As a specific example, the thickness of a single-section cell core unit is reduced to 3.1 mm, and the height of a 200-section electrolyzer can be reduced by 200 mm. The diameter of the membrane electrode is only 8 mm larger than the reaction zone, which is much smaller than the area of ​​membrane electrodes on the market.

[0058] See also Figure 6 The assembly method of the PEM water electrolyzer core unit comprises the following steps:

[0059] Step S1, assembling the membrane electrode 23 and the anode diffusion layer 24 to form a first assembly; as an example, the membrane electrode 23 and the anode diffusion layer 24 are stacked, and a small amount of glue is applied symmetrically at the side edges where they contact to simply fix them to form an assembly;

[0060] Step S2, placing the first assembly in the center;

[0061] Step S3, placing the anode seal and the frame 10 in sequence on the outer ring of the first assembly;

[0062] Step S4, placing the cathode diffusion layer 22 in the center;

[0063] Step S5, placing a cathode seal on the outer ring;

[0064] Step S6: Cover the pure flat partition plate 21 as a whole and apply pressure to tighten and stress seal. The typical pressure of stress sealing is 30 MPa.

[0065] Then restart the assembly of the next slot core unit.

[0066] In this embodiment, the anode seal is an anode sealing gasket 32 ​​; and the cathode seal is a cathode sealing gasket 31 .

[0067] When assembling the slot core unit, the membrane electrode and the anode diffusion layer can be integrated in advance, thus avoiding the risk of misalignment when assembling the membrane electrode made of soft materials separately. There is no dangerous gap between the lower surface of the membrane electrode and the anode diffusion layer, and the risk of rupture is low.

[0068] Example 2

[0069] This embodiment provides a cell core unit of a PEM water electrolyzer, and its structure and assembly method are similar to those of embodiment 1, and the difference from embodiment 1 is that the cathode sealing surface 11, the anode sealing surface 15 and the membrane electrode sealing surface 18 are rubber strip sealing surfaces bonded to the frame 10; the thickness of the rubber strips of the cathode sealing surface 11 and the anode sealing surface 15 is 0.1-0.2 mm; the thickness of the rubber strip of the membrane electrode sealing surface 18 is 0.3-0.4 mm. During assembly, the anode seal is the anode rubber sealing strip assembled at the anode sealing surface 15 and the membrane electrode sealing surface 18 of the frame 10; the cathode seal is the cathode rubber sealing strip assembled at the cathode sealing surface 11 of the frame 10.

[0070] Example 3

[0071] See also Figure 7 This embodiment provides a PEM water electrolyzer, which includes, from top to bottom, an upper end plate 41, an upper insulating plate 42, an upper current collecting plate 43, a stacked slot core unit 44 of the PEM water electrolyzer described in Example 1 or Example 2, a blind end current collecting plate 45, a blind end insulating plate 46 and a blind end plate 47.

[0072] The assembly process of the PEM water electrolyzer is as follows:

[0073] 1. First fix the upper end plate 41;

[0074] 2. Insert two positioning pins at the diagonal positions of the upper end plate 41;

[0075] 3. Insert the positioning pins into the upper insulating plate 42 and align them;

[0076] 4. Place the upper collecting plate 43;

[0077] 5. Stack the slot core units 44 in order from bottom to top;

[0078] 6. Place the blind end collector plate 45;

[0079] 7. Place the blind end insulation board 46;

[0080] 8. Place the blind end plate 47;

[0081] 9. Take out the positioning pins placed in step 2 and tighten the bolts diagonally in turn;

[0082] 10. Turn the entire electrolytic cell upside down and install the water inlet and hydrogen inlet connectors on the top.

[0083] The cell core unit of the PEM water electrolyzer and the PEM water electrolyzer of the present invention effectively reduce the thickness of the cell core unit while ensuring the sealing performance, and also reduce the number of components of the electrolyzer, so that the industrial feasibility is high, and at the same time, the area of ​​the membrane electrode is reduced as much as possible, and the material cost is low. When the cell core unit and the PEM water electrolyzer are assembled, the membrane electrode and the anode diffusion layer are integrated in advance, so that the risk of easy dislocation of the membrane electrode of the soft material when assembled separately is avoided. In addition, there is no dangerous gap between the lower surface of the membrane electrode and the anode diffusion layer, and the risk of rupture is small.

[0084] Those skilled in the art should understand that those skilled in the art can implement variations by combining the prior art and the above embodiments, which will not be described in detail here. Such variations do not affect the essential content of the present invention, and will not be described in detail here.

[0085] The above describes the preferred embodiments of the present invention. It should be understood that the present invention is not limited to the above-mentioned specific embodiments, and the devices and structures that are not described in detail should be understood to be implemented in a common manner in the art; any technician familiar with the art can use the above-disclosed methods and technical contents to make many possible changes and modifications to the technical solutions of the present invention without departing from the scope of the technical solutions of the present invention, or modify them into equivalent embodiments of equivalent changes, which does not affect the essential content of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention are still within the scope of protection of the technical solutions of the present invention.

Claims

1. A cell core unit of a PEM water electrolyzer, comprising a cathode diffusion layer (22), a membrane electrode (23), and an anode diffusion layer (24); the membrane electrode (23) is arranged between the cathode diffusion layer (22) and the anode diffusion layer (24) as a reaction zone; the diameter of the cathode diffusion layer (22) is smaller than the diameter of the membrane electrode (23); characterized in that: The side of the reaction zone is covered with a flat partition plate (21) and the outer side is provided with a single-layer frame (10); the upper and lower sides of the membrane electrode are the cathode and anode of the slot core unit respectively; A reaction zone through hole (1) is formed in the center of the frame (10); a first through hole (13) serving as a hydrogen channel and a second through hole (14) serving as a water channel are respectively provided outside the reaction zone through hole (1) and at a vertical position and a horizontal position; The upper surface of the frame (10) is provided with a cathode microchannel (12) at a vertical position outside the reaction zone through hole (1) via a plurality of cathode sealing surfaces (11), and the lower surface is provided with an anode microchannel (16) at a horizontal position outside the reaction zone through hole (1) via a plurality of anode sealing surfaces (15); an inner circle sink (17) is provided between the anode microchannel (16) and the reaction zone through hole (1); and a full circle membrane electrode sealing surface (18) is provided on the inner side of the inner circle sink (17); The cathode diffusion layer (22) is arranged on the upper layer of the reaction zone through hole (1), and the membrane electrode (23) and the anode diffusion layer (24) are arranged on the lower layer of the reaction zone through hole (1) and close to the inner side of the inner circle sink (17); the anode diffusion layer (24) is divided into upper and lower layers, the upper layer close to the membrane electrode (23) is a titanium felt (241) with compacted edges, and the lower layer is a water-permeable titanium mesh (242); the diameter of the membrane electrode (23) is not greater than the diameter of the anode diffusion layer (24) and not less than the outer diameter of the membrane electrode sealing surface (18); the outer side of the reaction zone is sealed by the cathode sealing surface (11), the anode sealing surface (15) and the membrane electrode sealing surface (18) of the frame (10); the flat partition plate (21) is provided with through holes corresponding to the first through hole (13) and the second through hole (14), and is stacked on the outer side of the frame (10).

2. A cell core unit of a PEM water electrolyzer according to claim 1, characterized in that: The cathode sealing surface (11), the anode sealing surface (15) and the membrane electrode sealing surface (18) are convex ridge structure end surfaces on the surface of the frame (10); the protruding heights of the cathode sealing surface (11) and the anode sealing surface (15) are 0.1 to 0.2 mm; and the protruding height of the membrane electrode sealing surface (18) is 0.3 to 0.4 mm.

3. A cell core unit of a PEM water electrolyzer according to claim 2, characterized in that: A cathode sealing gasket (31) is provided between the frame (10) and the cathode diffusion layer (22), and the cathode sealing surface (11) is sealed by the cathode sealing gasket (31); and an anode sealing gasket (32) is provided between the frame (10) and the anode diffusion layer (24), and the anode sealing surface (15) is sealed by the anode sealing gasket (32).

4. The cell core unit of a PEM water electrolyzer according to claim 1, characterized in that: The cathode sealing surface (11), the anode sealing surface (15) and the membrane electrode sealing surface (18) are rubber strip sealing surfaces bonded to the frame (10); the thickness of the rubber strips of the cathode sealing surface (11) and the anode sealing surface (15) is 0.1-0.2 mm; the thickness of the rubber strips of the membrane electrode sealing surface (18) is 0.3-0.4 mm.

5. A cell core unit of a PEM water electrolyzer according to claim 1, 3 or 4, characterized in that: The cathode diffusion layer (22) is formed by bonding and stacking multiple layers of carbon paper; the area of ​​the middle water-permeable portion of the titanium felt (241) is consistent with the area of ​​the cathode diffusion layer (22).

6. A cell core unit of a PEM water electrolyzer according to claim 3, characterized in that: The cathode sealing gasket (31) and the anode sealing gasket (32) are both made of PTFE and have a thickness of 0.1-0.3 mm.

7. A method for assembling a core unit of a PEM water electrolyzer, characterized in that: The cell core unit for assembling the PEM water electrolyzer according to any one of claims 1 to 6 comprises the following steps: Step S1, assembling the membrane electrode (23) and the anode diffusion layer (24) to form a first assembly; Step S2, placing the first assembly in the center; Step S3, placing an anode seal and a frame (10) in sequence on the outer ring of the first assembly; Step S4, placing a cathode diffusion layer (22) in the center; Step S5, placing a cathode seal on the outer ring; Step S6: Cover the flat partition plate (21) as a whole and apply pressure to tighten and stress-tighten it.

8. The method for assembling a PEM water electrolyzer core unit according to claim 7, characterized in that: The anode seal is an anode sealing gasket (32) or an anode rubber sealing strip mounted on the anode sealing surface (15) and the membrane electrode sealing surface (18) of the frame (10); the cathode seal is a cathode sealing gasket (31) or a cathode rubber sealing strip mounted on the cathode sealing surface (11) of the frame (10).

9. A PEM water electrolyzer, characterized in that: The invention comprises, from top to bottom, an upper end plate (41), an upper insulating plate (42), an upper current collecting plate (43), a stacked cell core unit (44) of a PEM water electrolyzer as claimed in any one of claims 1 to 6, a blind end current collecting plate (45), a blind end insulating plate (46) and a blind end plate (47).

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