High-voltage PEM electrolytic bath

Abstract

The high-voltage PEM electrolytic bath comprises a first end plate, a second end plate, an outer sleeve and an electrolysis assembly, the electrolysis assembly is arranged between the first end plate and the second end plate; the outer sleeve is arranged on the outer side of the electrolysis assembly in a sleeving manner; one end of the outer sleeve is connected with the first end plate, and the other end of the outer sleeve is connected with the second end plate; and a gap is formed between the outer sleeve and the electrolysis assembly and is filled with protective gas. According to the structure, higher hydrogen production pressure can be achieved, meanwhile, the sealing reliability and the running reliability of the electrolytic cell are effectively improved, the implementation cost is low, power consumption is low, disassembly and assembly are convenient, maintenance is convenient, stability is good, and the actual use requirement can be well met.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrolysis and fuel cells, and particularly relates to a high-pressure PEM electrolyzer. Background Art

[0002] With the advancement of the global carbon neutrality goal, the importance of hydrogen energy as a zero-carbon energy carrier has become increasingly prominent. In the electrolytic water hydrogen production technology, the proton exchange membrane (PEM) electrolyzer has become one of the core technologies for producing high-quality green hydrogen due to its advantages such as high current density, fast response speed, high gas production purity (>99.99%), and the ability to be directly coupled with renewable energy power generation systems. Compared with alkaline electrolyzers (the hydrogen production pressure is usually ≤1.6 MPa), the PEM electrolyzer can achieve a high-pressure hydrogen output of 3 MPa by optimizing the cathode flow channel design and sealing structure, significantly reducing the energy consumption and equipment investment in the downstream hydrogen compression link.

[0003] However, there are significant technical bottlenecks in increasing the hydrogen production pressure of existing PEM electrolyzers. When the target hydrogen transmission pressure exceeds 3 MPa, the risk of seal failure inside the electrolyzer increases sharply. The core sealing interfaces of the PEM electrolyzer include the edge seal between the membrane electrode assembly (MEA) and the bipolar plate, the flange seal between the bipolar plate and the end plate, and the connection seal of the hydrogen outlet pipeline. High-pressure hydrogen molecules are extremely easy to leak through micron-level sealing gaps; traditional sealing materials such as polytetrafluoroethylene (PTFE), ethylene propylene diene monomer (EPDM), and fluororubber (FKM) are prone to plastic deformation under pressures above 3 MPa, resulting in stress attenuation at the sealing interface; at the same time, the sealing path of the existing planar sealing structure is short (usually <5 mm), which cannot effectively block the penetration of high-pressure hydrogen. Some existing PEM cells improve the pressure resistance by using multi-layer composite gaskets. However, there will still be hydrogen leakage problems caused by gasket aging under long-term high-pressure working conditions, and it is difficult to achieve stable operation above 3 MPa because the pressure-bearing capacity of the electrolyzer cavity structure has not been optimized. Therefore, how to break through the seal failure and structural strength limitations of the PEM cell under high pressure and achieve stable and efficient operation of the PEM electrolyzer at pressures above 3 MPa has become a technical problem in this field. Summary of the Invention

[0004] The embodiments of the present invention provide a high-pressure PEM electrolyzer, aiming to solve the problems that the existing PEM electrolyzers are limited by structural strength, are prone to seal deformation and aging, seal failure, and it is difficult to achieve stable and efficient operation at pressures above 3 MPa.

[0005] To solve the above technical problems, an embodiment of the present invention provides a high-pressure PEM electrolyzer, which includes a first end plate (i.e., the upper end plate), a second end plate (i.e., the lower end plate), an outer sleeve, and an electrolysis assembly; the electrolysis assembly is disposed between the first end plate and the second end plate; the outer sleeve is sleeved outside the electrolysis assembly; one end of the outer sleeve is connected to the first end plate, and the other end of the outer sleeve is connected to the second end plate; a gap is provided between the outer sleeve and the electrolysis assembly, and a protective gas is filled in the gap.

[0006] As a preferred embodiment, the pressure in the gap is the same as the hydrogen outlet pressure on the cathode side of the electrolysis assembly. This can ensure that the internal and external pressures of the seal are close, effectively improving the hydrogen pressure and the reliability of the seal.

[0007] As a preferred embodiment, the outer sleeve is a metal sleeve; the protective gas is at least one of nitrogen, argon, or air.

[0008] As a preferred embodiment, the outer sleeve is welded to the first end plate, and the outer sleeve is welded to the second end plate. This makes the outer sleeve form an integral body with the first end plate and the second end plate, further improving the reliability.

[0009] As a preferred embodiment, a first gasket is provided between the outer sleeve and the first end plate, and the first gasket is respectively in contact with the outer sleeve and the first end plate; a second gasket is provided between the outer sleeve and the second end plate, and the second gasket is respectively in contact with the outer sleeve and the second end plate. Such a setting enables the outer sleeve to maintain good sealing with the first end plate and the second end plate.

[0010] As a preferred embodiment, the outer sleeve, the first gasket, and the first end plate are connected by several first fastening bolts, and the several first fastening bolts are evenly arranged; the outer sleeve, the second gasket, and the second end plate are connected by several second fastening bolts, and the several second fastening bolts are evenly arranged.

[0011] As a preferred embodiment, the electrolysis assembly and the outer sleeve have the same shape; the first end plate and the second end plate have the same shape.

[0012] As a preferred embodiment, the first end plate is a square end plate or a circular end plate, preferably a circular end plate; the second end plate is a square end plate or a circular end plate, preferably a circular end plate; the electrolysis assembly is a square assembly or a circular assembly, preferably a circular assembly.

[0013] As a preferred embodiment, an anodic water inlet, an anodic water outlet, a first cathodic hydrogen outlet and a second cathodic hydrogen outlet are provided on the first end plate. The anodic water inlet and the anodic water outlet are diagonally arranged; the first cathodic hydrogen outlet and the second cathodic hydrogen outlet are diagonally arranged. Pure water for electrolysis enters the electrolysis assembly through the anodic water inlet, and an electrolytic water reaction occurs under the action of an external power supply. Oxygen is generated on the anodic side and hydrogen is generated on the cathodic side. The circulation of pure water for electrolysis and the transmission of oxygen generated on the anodic side are realized through the anodic water inlet and the anodic water outlet. The transmission of hydrogen generated on the cathodic side can be realized through the two hydrogen outlets.

[0014] As a preferred embodiment, a high-pressure gas inlet valve and a high-pressure gas outlet valve are further provided on the first end plate. The high-pressure gas inlet valve and the high-pressure gas outlet valve are respectively communicated with the gap. In this way, the high-pressure gas in the gap can be connected to an external high-pressure steel cylinder (a traditional steel cylinder can be 12 MPa) or a variable-frequency compressor pump through the high-pressure gas outlet valve, with low cost and low power consumption.

[0015] As a preferred embodiment, the electrolysis assembly includes an inner end plate, a first insulating plate (i.e., the upper insulating plate), a first current collector plate (i.e., the upper current collector plate), a battery body, a second current collector plate and a second insulating plate which are stacked in sequence; the inner end plate is in contact with the first end plate; the second insulating plate is in contact with the second end plate. The electrolysis assembly is the main place where electrolytic water occurs. The inner end plate and the second end plate are fixed by a plurality of electrolytic cell fastening screws, and the electrolytic cell fastening bolts are arranged around the outside of the battery body.

[0016] As a preferred embodiment, the battery body includes several single cells stacked in sequence; each single cell includes a first pole frame, a membrane electrode, a second pole frame and a bipolar plate which are stacked in sequence; the first pole frame is arranged close to the first current collector plate.

[0017] As a preferred embodiment, the electrolysis assembly further includes a first current collector plate ear and a second current collector plate ear; the first current collector plate ear is connected to the first current collector plate, and one end of the first current collector plate ear passes through the first end plate and protrudes from the first end plate; the second current collector plate ear is connected to the second current collector plate, and one end of the second current collector plate ear passes through the first end plate and protrudes from the first end plate.

[0018] Compared with the prior art, the technical solution of the embodiment of the present invention has the following beneficial effects: By providing an outer sleeve and controlling the gap between the outer sleeve and the electrolysis component, an external high-pressure gas chamber is formed through this gap, which can strictly control the pressure difference inside and outside the electrolysis component, further improve the reliability of the seal, and thus achieve a higher hydrogen outlet pressure. The structure of the present application can achieve a higher hydrogen production pressure ≥ 3 MPa. At the same time, the reliability of the seal and the reliability of the electrolytic cell operation are effectively improved, with low cost and low power consumption, and it can well meet the actual use needs. The structure of the present application is simple, easy to disassemble and assemble, convenient for maintenance, has good stability, is economical, safe and practical, and can be achieved without major improvement to the structure of the electrolytic cell, and can be used for large-scale production applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0020] Figure 1 It is a schematic diagram of the overall structure of a high-pressure PEM electrolytic cell according to an embodiment of the present invention; Figure 2 is Figure 1 A schematic cross-sectional structure diagram of the high-pressure PEM electrolytic cell; Figure 3 is Figure 1 An exploded structure diagram of the high-pressure PEM electrolytic cell; Figure 4 is Figure 1 A schematic internal structure diagram of the high-pressure PEM electrolytic cell; Figure 5 is Figure 1 An enlarged structure diagram of the first end plate;

[0021] The realization of the object of the present invention, functional features and advantages will be further described with reference to the embodiments and the drawings. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0023] In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0024] The maximum hydrogen outlet pressure of a traditional PEM cell can only reach 3 MPa. If the pressure is further increased, the pressure difference between the hydrogen side of the cathode of the electrolytic cell and the external atmospheric pressure is too large, and the risk of deformation and aging of the seal is aggravated. In this application, by providing an outer sleeve, a high-pressure gas chamber is formed between the outer sleeve and the electrolytic assembly, which can strictly control the pressure difference inside and outside the electrolytic cell, further improve the reliability of the seal, and thus achieve a higher hydrogen outlet pressure.

[0025] Through the structure of this application, the hydrogen outlet pressure can be increased to 5 MPa - 7 MPa, which can reduce the compression power consumption of subsequent high-pressure hydrogen storage links (such as 35 MPa hydrogen storage tanks) by more than 40%, while reducing the number of compressor stages and equipment investment. In the embodiments of this application, high pressure means > 3 MPa.

[0026] Specifically, as Figures 1 to 5 shown, an embodiment of the present invention provides a high-pressure PEM electrolytic cell, which includes a first end plate 10 (i.e., the upper end plate), a second end plate 20 (i.e., the lower end plate), an outer sleeve 30, and an electrolytic assembly 40; the electrolytic assembly 40 is disposed between the first end plate 10 and the second end plate 20; the outer sleeve 30 is sleeved outside the electrolytic assembly 40; one end of the outer sleeve 30 is connected to the first end plate 10, and the other end of the outer sleeve 30 is connected to the second end plate 20; a gap 50 is provided between the outer sleeve 30 and the electrolytic assembly 40, and a protective gas is filled in the gap 50.

[0027] As a preferred embodiment, the pressure in the gap 50 is the same as the hydrogen outlet pressure on the cathode side of the electrolytic assembly 40. This can ensure that the internal and external pressures of the seal are close, effectively improving the hydrogen pressure and the reliability of the seal.

[0028] In the embodiments of this application, the first end plate, the second end plate, the outer sleeve, and the electrolytic assembly are all set to be adapted to each other (including aspects such as shape and size). In this way, the reliability of the mutual connection can be well ensured.

[0029] As a preferred embodiment, the outer sleeve 30 is a metal sleeve; the protective gas is at least one of nitrogen, argon, or air.

[0030] As a preferred embodiment, the outer sleeve 30 is welded to the first end plate 10, and the outer sleeve 30 is welded to the second end plate 20. This makes the outer sleeve 30 form an integral body with the first end plate 10 and the second end plate 20, further improving the reliability of the structure.

[0031] As a preferred embodiment, a first gasket 60 is provided between the outer sleeve 30 and the first end plate 10, and the first gasket 60 is respectively in contact with the outer sleeve 30 and the first end plate 10; a second gasket 70 is provided between the outer sleeve 30 and the second end plate 20, and the second gasket 70 is respectively in contact with the outer sleeve 30 and the second end plate 20. With this arrangement, the outer sleeve 30 can maintain good sealing with the first end plate 10 and the second end plate 20.

[0032] As a preferred embodiment, the outer sleeve 30, the first gasket 60 and the first end plate 10 are connected by several first fastening bolts 80, and the several first fastening bolts 80 are evenly arranged; the outer sleeve 30, the second gasket 70 and the second end plate 20 are connected by several second fastening bolts 90, and the several second fastening bolts 90 are evenly arranged.

[0033] As a preferred embodiment, the electrolysis assembly 40 has the same shape as the outer sleeve 30; the first end plate 10 has the same shape as the second end plate 20.

[0034] As a preferred embodiment, the first end plate 10 is a square end plate or a circular end plate, preferably a circular end plate; the second end plate 20 is a square end plate or a circular end plate, preferably a circular end plate; the electrolysis assembly 40 is a square assembly or a circular assembly, preferably a circular assembly.

[0035] As a preferred embodiment, please refer to again Figure 1 ., an anodic water inlet 11, an anodic water outlet 12, a first cathodic hydrogen outlet 13 and a second cathodic hydrogen outlet 14 are provided on the first end plate 10, and the anodic water inlet 11 and the anodic water outlet 12 are diagonally arranged; the first cathodic hydrogen outlet 13 and the second cathodic hydrogen outlet 14 are diagonally arranged. Pure water for electrolysis enters the electrolysis assembly through the anodic water inlet, and an electrolytic water reaction occurs under the action of an external power source. Oxygen is generated on the anodic side, and hydrogen is generated on the cathodic side. The circulation of pure water for electrolysis and the transmission of oxygen generated on the anodic side are realized through the anodic water inlet and the anodic water outlet. The transmission of hydrogen generated on the cathodic side can be realized through the two hydrogen outlets.

[0036] As a preferred embodiment, a high-pressure gas inlet valve 15 and a high-pressure gas outlet valve 16 are further provided on the first end plate 10, and the high-pressure gas inlet valve 15 and the high-pressure gas outlet valve 16 are respectively communicated with the gap 50. In this way, the high-pressure gas in the gap 50 can be connected to an external high-pressure steel cylinder (a traditional steel cylinder can be 12 MPa) or a variable-frequency compression pump through the high-pressure gas outlet valve, with low cost and low power consumption.

[0037] As a preferred embodiment, as Figure 3 shown, the electrolysis assembly 40 includes an inner end plate 41, a first insulating plate 42 (i.e., the upper insulating plate), a first current collector plate 43 (i.e., the upper current collector plate), a battery body 44, a second current collector plate 45, and a second insulating plate 46 that are sequentially stacked; the inner end plate 41 is in contact with the first end plate 10; the second insulating plate 46 is in contact with the second end plate 20. The electrolysis assembly 40 is the main place where water electrolysis occurs. The inner end plate 41 and the second end plate 20 are fixed by a plurality of electrolytic cell fastening screws 47, and the electrolytic cell fastening bolts 47 are arranged around the outside of the battery body 44.

[0038] As a preferred embodiment, please refer to Figure 3 again, the battery body 44 includes several single cells 441 stacked; each single cell 441 includes a first pole frame 4411, a membrane electrode 4412, a second pole frame 4413, and a bipolar plate 4414 that are sequentially stacked; the first pole frame 4411 is arranged close to the first current collector plate 43.

[0039] As a preferred embodiment, the electrolysis assembly 40 further includes a first current collector plate ear 48 and a second current collector plate ear 49; the first current collector plate ear 48 is connected to the first current collector plate 43, and one end of the first current collector plate ear 48 passes through the first end plate 10 and protrudes from the first end plate 10; the second current collector plate ear 49 is connected to the second current collector plate 45, and one end of the second current collector plate ear 49 passes through the first end plate 10 and protrudes from the first end plate 10.

[0040] When assembling the high-pressure PEM cell of the present application, first place the second end plate at the bottom, sequentially install the second insulating plate and the second current collector plate, then stack the single cells in sequence, then place the first current collector plate and the first insulating plate, and finally install the inner end plate. Align the screw holes of the inner end plate and the second end plate, and fix them through the electrolytic cell fastening screws, so as to realize the assembly of the inner electrolytic cell.

[0041] Then assemble the outer sleeve. First, lay a second sealing gasket on the surface of the second end plate, align the hole positions of the second sealing gasket and the second end plate, and fix them through the second fastening screws.

[0042] Then install the first end plate, lay a first gasket on the top of the outer sleeve, place the first end plate, and fix it with the first fastening screw. The anodic water inlet, the first cathodic hydrogen outlet, the anodic water outlet, and the second cathodic hydrogen outlet of the first end plate are aligned with the built-in end plate one by one.

[0043] When the electrolytic cell is operating, introduce protective gas, such as nitrogen, argon, air, etc., through the high-pressure protective gas inlet valve. The pressure of the protective gas is kept consistent with the hydrogen outlet pressure of the electrolytic cell and adjusted in a timely manner as needed. This structure of the electrolytic cell can achieve a higher hydrogen production pressure (≥3 MPa), while improving the reliability of the seal and the reliability of the operation of the electrolytic cell.

[0044] In this application, by setting the outer sleeve and controlling the gap between the outer sleeve and the electrolytic assembly, an external high-pressure gas chamber is formed through this gap, which can strictly control the pressure difference inside and outside the electrolytic assembly, further improve the reliability of the seal, and thus achieve a higher hydrogen outlet pressure. The structure of this application can achieve a higher hydrogen production pressure ≥3 MPa. At the same time, it effectively improves the reliability of the seal and the reliability of the operation of the electrolytic cell, with low cost and low power consumption, and can well meet the actual use needs. The structure of this application is simple, easy to disassemble and assemble, convenient for maintenance, has good stability, is economically safe and practical, and can be realized without major improvement to the structure of the electrolytic cell, and can be used for large-scale production applications.

[0045] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A high-pressure PEM electrolyzer, characterized in that, It includes a first end plate, a second end plate, an outer sleeve, and an electrolysis assembly; the electrolysis assembly is disposed between the first end plate and the second end plate; the outer sleeve is sleeved outside the electrolysis assembly; one end of the outer sleeve is connected to the first end plate, and the other end of the outer sleeve is connected to the second end plate; a gap is provided between the outer sleeve and the electrolysis assembly, and a protective gas is filled in the gap.

2. The high-pressure PEM electrolyzer according to claim 1, characterized in that, The pressure in the gap is the same as the hydrogen evolution pressure on the cathode side of the electrolysis assembly; The outer sleeve is a metal sleeve; the protective gas is at least one of nitrogen, argon, or air.

3. The high-pressure PEM electrolyzer according to claim 1, wherein The outer sleeve is connected to the first end plate by welding, and the outer sleeve is connected to the second end plate by welding.

4. The high-pressure PEM electrolyzer according to claim 1, wherein, A first gasket is provided between the outer sleeve and the first end plate, and the first gasket is respectively in contact with the outer sleeve and the first end plate; a second gasket is provided between the outer sleeve and the second end plate, and the second gasket is respectively in contact with the outer sleeve and the second end plate.

5. The high-pressure PEM electrolyzer according to claim 4, characterized in that, The outer sleeve, the first gasket, and the first end plate are connected by several first fastening bolts, and the several first fastening bolts are evenly arranged; the outer sleeve, the second gasket, and the second end plate are connected by several second fastening bolts, and the several second fastening bolts are evenly arranged.

6. The high-pressure PEM electrolyzer according to claim 1, characterized in that, The electrolysis assembly has the same shape as the outer sleeve; the first end plate has the same shape as the second end plate.

7. The high-pressure PEM electrolyzer according to claim 1, wherein, An anodic water inlet, an anodic water outlet, a first cathode hydrogen outlet, and a second cathode hydrogen outlet are provided on the first end plate, and the anodic water inlet and the anodic water outlet are diagonally arranged; the first cathode hydrogen outlet and the second cathode hydrogen outlet are diagonally arranged.

8. The high-pressure PEM electrolytic cell according to claim 1, characterized in that, A high-pressure gas inlet valve and a high-pressure gas outlet valve are further provided on the first end plate, and the high-pressure gas inlet valve and the high-pressure gas outlet valve are respectively communicated with the gap.

9. The high-pressure PEM electrolyzer according to claim 1, characterized in that, The electrolysis assembly includes an inner end plate, a first insulating plate, a first current collector plate, a battery body, a second current collector plate, and a second insulating plate which are stacked in sequence; the inner end plate is in contact with the first end plate; the second insulating plate is in contact with the second end plate.

10. The high-pressure PEM electrolyzer according to claim 9, characterized in that, The battery body includes several single cells stacked; each single cell includes a first pole frame, a membrane electrode, a second pole frame, and a bipolar plate which are stacked in sequence; the first pole frame is close to the first current collector plate; The electrolysis assembly further includes a first current collector plate ear and a second current collector plate ear; the first current collector plate ear is connected to the first current collector plate, and one end of the first current collector plate ear passes through the first end plate and protrudes from the first end plate; the second current collector plate ear is connected to the second current collector plate, and one end of the second current collector plate ear passes through the first end plate and protrudes from the first end plate.

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