A high-pressure electrolytic cell with an elastic flow field structure

Abstract

The present invention provides a high-pressure electrolytic cell with an elastic flow field structure, which includes a lower end plate, a lower insulating plate, a lower electrode plate, a composite flow field unit, an upper electrode plate, an upper insulating plate, and an upper end plate stacked upward in sequence; bolts fixedly connect the upper and lower end plates; the composite flow field unit includes a membrane frame and a composite flow field structure. The composite flow field structure is disposed in the accommodating cavity of the membrane frame and includes a lower flow field structure, a membrane electrode, and an upper flow field structure stacked upward in sequence. The lower and upper flow field structures are elastic in the direction perpendicular to the surface of the membrane electrode and are respectively provided with lower and upper water storage and exhaust cavities; a plurality of connected oxygen-water and hydrogen-water inlets and outlets are provided at the edges of the membrane frame, the upper electrode plate, the upper insulating plate, and the upper end plate, and are respectively communicated with the upper water storage and exhaust cavity and the lower water storage and exhaust cavity. The present invention improves the water-gas exchange conditions, realizes the pump-free operation of the high-pressure electrolytic cell, and the elastic composite flow field structure maintains the stability of electrical contact, greatly improving the working efficiency of the electrolytic cell under high gas pressure.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrolyzed water, and particularly relates to a high-pressure electrolytic cell with an elastic flow field structure. Background Art

[0002] The traditional PEM hydrogen production electrolytic cell is formed by tightly pressing multiple layers of components such as titanium plates, titanium felts, titanium meshes, and proton membrane electrodes coated with catalysts, and hydrogen and oxygen sealing frames together in series by bolts through two end plates. During operation, an uninterrupted running water pump is also required to replenish water more fully. One or several water inlets and outlets are provided on the oxygen evolution side of the electrolytic cell, and the continuous supply of water is completed by the water pump. Similarly, one or several inlets and outlets are also provided on the hydrogen evolution side of the electrolytic cell to discharge hydrogen; the porous titanium felt or titanium foam closely attached to both sides of the membrane electrode and the titanium mesh form a flow field that can allow gas to pass through and water to flow, and then be connected to the external water and gas circuits; maintaining good gas-permeable and water-flowing conditions is one of the important conditions to ensure the performance of the electrolytic cell. Poor flow field conditions will lead to fatal defects such as water shortage and overheating of the membrane electrode, resulting in premature failure of the electrolytic cell. At the same time, the flow field composed of porous titanium felt and titanium mesh also needs to have good electrical conductivity to reduce the ohmic loss during operation and improve the performance of the electrolytic cell.

[0003] However, the flow field structure composed of porous titanium felt or titanium foam and titanium mesh lacks elasticity. When there is a high pressure on one side of the membrane electrode, for example, on the hydrogen evolution side, the flow field on the oxygen evolution side is compressed, while the flow field on the hydrogen evolution side expands. However, the inelastic flow field on the hydrogen evolution side cannot compensate for this expansion. Therefore, the pressing force of the flow field on the hydrogen evolution side is greatly reduced, resulting in a significant reduction in the contact points between the flow field on the hydrogen evolution side, the titanium plate, and the membrane electrode, and an increase in resistance, seriously deteriorating the performance of the electrolytic cell, usually reducing the efficiency of the electrolytic cell by more than 20%. Another fatal problem is that when the electrode area is very large, due to the limited mesh gaps formed by the titanium mesh, even though there are flow channel grooves with a certain depth engraved on the electrode plate in the prior art, when the electrolytic cell operates at a high current density (>1 A·cm –2 ), the generated gas flow will squeeze out the replenishing water between the mesh holes and the flow channel grooves, resulting in local water shortage and overheating of the membrane electrode, seriously affecting the service life of the electrolytic cell.

[0004] Therefore, an improved technical solution is needed to address the above deficiencies in the prior art. Summary of the Invention

[0005] In view of the above-mentioned deficiencies of the prior art, the purpose of the present invention is to provide a high-pressure electrolytic cell with an elastic flow field structure, which is used to solve the problems that the flow field structure of the PEM hydrogen production electrolytic cell in the prior art lacks elasticity, resulting in a significant decrease in the efficiency of the electrolytic cell under high pressure, and the problems that when the electrolytic cell operates at a high current density, it causes local water shortage, overheating of the membrane electrode, and affects the service life of the electrolytic cell.

[0006] To achieve the above and other related objectives, the present invention provides a high-pressure electrolytic cell with an elastic flow field structure. The high-pressure electrolytic cell includes a lower end plate, a lower insulating plate, a lower electrode plate, a composite flow field unit, an upper electrode plate, an upper insulating plate, and an upper end plate stacked upward in sequence;

[0007] A plurality of first bolt holes are formed at the edge of the lower end plate, and the upper surface of the lower end plate is flat;

[0008] The lower insulating plate is stacked above the lower end plate;

[0009] The lower electrode plate is stacked above the lower insulating plate;

[0010] The composite flow field unit is stacked above the lower electrode plate. The composite flow field unit includes a membrane frame and a composite flow field structure. The membrane frame has a receiving cavity, and the composite flow field structure is disposed in the receiving cavity. The composite flow field structure includes a lower flow field structure, a membrane electrode, and an upper flow field structure stacked upward in sequence. The lower flow field structure and the upper flow field structure are both elastic in a direction perpendicular to the surface of the membrane electrode. A lower water storage and exhaust cavity is provided on a side of the lower flow field structure facing away from the membrane electrode, and an upper water storage and exhaust cavity is provided on a side of the upper flow field structure facing away from the membrane electrode;

[0011] The upper electrode plate is located above the composite flow field unit;

[0012] The upper insulating plate is located above the upper electrode plate;

[0013] The upper end plate is located above the upper insulating plate, and a plurality of second bolt holes corresponding to the first bolt holes are provided at the edge. The bolts fixedly connect the upper end plate and the lower end plate through the first bolt holes and the second bolt holes;

[0014] Moreover, a plurality of connected oxygen-water inlets and outlets and a plurality of connected hydrogen-water inlets and outlets are provided at the edges of the membrane frame, the upper electrode plate, the upper insulating plate, and the upper end plate. The upper water storage and exhaust cavity is communicated with the oxygen-water inlets and outlets, and the lower water storage and exhaust cavity is communicated with the hydrogen-water inlets and outlets.

[0015] Preferably, both the lower flow field structure and the upper flow field structure include flow field plates. A plurality of horizontal grooves and a plurality of vertical grooves are provided on the flow field plates. Each horizontal groove penetrates the upper and lower surfaces of the flow field plate and is arranged in parallel with each other. The vertical grooves are formed on a side of the flow field plate facing away from the membrane electrode and intersect with the horizontal grooves; a plurality of the horizontal grooves and vertical grooves in the upper flow field structure enclose the upper water storage and exhaust cavity, and a plurality of the horizontal grooves and vertical grooves in the lower flow field structure enclose the lower water storage and exhaust cavity.

[0016] Preferably, a water guiding layer is further disposed between the flow field plate and the membrane electrode. A plurality of water guiding grooves are provided on one side of the water guiding layer adjacent to the flow field plate. The plurality of water guiding grooves are arranged in parallel, and the water guiding grooves intersect with the transverse grooves on the adjacent flow field plate in space.

[0017] Preferably, the water guiding layer includes a flat plate and a water guiding component. The water guiding component is disposed on the flat plate, and a plurality of parallel water guiding grooves are formed on the water guiding component.

[0018] Preferably, the plurality of transverse grooves divide the flow field plate into several strip-shaped grooves, and conductive strips are wrapped on the upper and lower surfaces of each strip-shaped groove.

[0019] Preferably, a plurality of upper flow channel grooves are formed on one side of the membrane frame adjacent to the upper electrode plate. Each upper flow channel groove is in one-to-one correspondence and communication with the oxygen and water inlet and outlet on the membrane frame; a plurality of lower flow channel grooves are formed on one side of the membrane frame adjacent to the lower electrode plate. Each lower flow channel groove is in one-to-one correspondence and communication with the hydrogen and water inlet and outlet on the membrane frame.

[0020] Preferably, a pressure membrane ring is provided at the circumferential edge where the membrane electrode protrudes beyond the flow field plate. The pressure membrane ring circumferentially surrounds the outer edge of the flow field plate, and a plurality of grooves are formed on the pressure membrane ring. The plurality of grooves communicate with each other with the upper water storage and exhaust cavity and communicate with the upper flow channel groove.

[0021] Preferably, a first sealing ring is disposed in the accommodating cavity. The first sealing ring is located below the membrane electrode and surrounds the circumferential edge of the membrane electrode.

[0022] Preferably, a second sealing ring is provided at the oxygen and water inlet and outlet on each membrane frame. The second sealing ring is located on one side of the membrane frame adjacent to the lower flow field structure; a third sealing ring is provided at the hydrogen and water inlet and outlet on each membrane frame. The third sealing ring is located on one side of the membrane frame adjacent to the upper flow field structure.

[0023] Preferably, a plurality of upper electrode plates and the composite flow field units are provided, and the upper electrode plates and the composite flow field units are alternately arranged to form a multi-stage series-connected multi-stage high-voltage electrolytic cell.

[0024] As described above, the high-voltage electrolytic cell with an elastic flow field structure of the present invention has the following beneficial effects:

[0025] The present invention uses an elastic upstream flow field structure, a downstream flow field structure, and conductive strips coated on the upstream flow field structure and the downstream flow field structure, which solves the problems that in the long-term use of a high-pressure electrolytic cell, due to permanent compressive deformation, the pressing force between the flow field and the electrode plate decreases, the number of electrical contact points decreases, and the contact resistance increases, resulting in a decrease in the efficiency of the high-pressure electrolytic cell. At the same time, the transverse grooves and vertical grooves on the flow field plate together form a large-volume water storage and exhaust cavity, which provides more water-vapor buffering and exchange space per unit area, realizes the pump-free operation of the high-pressure electrolytic cell, and the elastic composite flow field structure maintains the stability of electrical contact, greatly improving the working efficiency of the electrolytic cell under high gas pressure. In addition, the water storage and exhaust cavity has a good buffering effect, greatly reducing the flow resistance, greatly improving the efficiency of water-vapor exchange between the electrolytic cell and the outside, thus providing good conditions for water flow heat dissipation and gas discharge, and also greatly reducing the cost and weight compared with the traditional electrolytic cell.

[0026] When the high-pressure electrolytic cell in the present invention operates under a pressure difference of 1 Mpa on both sides, under the same conditions, the efficiency of the electrolytic cell is more than 18% higher than that of the traditional electrolytic cell, and the overall efficiency of the entire high-pressure electrolytic cell is increased by more than 20%. Moreover, the high-pressure electrolytic cell in the present invention realizes a current density of 1.5 A·cm –2 under the condition of no pump, with the pressure on the hydrogen evolution side being 3.5 Mpa and the pressure on the oxygen evolution side being 3 Mpa, and stably operates for more than five thousand hours. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It shows a schematic exploded view of a high-pressure electrolytic cell with an elastic flow field structure in Embodiment 1 of the present invention.

[0028] Figure 2 It shows Figure 1 a combined three-dimensional structure schematic diagram.

[0029] Figure 3 It shows a schematic exploded view of a composite flow field structure in Embodiment 1 of the present invention.

[0030] Figure 4 It shows a three-dimensional structure schematic diagram of a composite flow field structure in Embodiment 1 of the present invention.

[0031] Figure 5 It shows a three-dimensional structure schematic diagram of a flow field plate in Embodiment 1 of the present invention.

[0032] Figure 6a It shows a schematic exploded view of one of the water guiding layers in Embodiment 1 of the present invention.

[0033] Figure 6b It shows a schematic exploded view of another water guiding layer in Embodiment 1 of the present invention.

[0034] Figure 7a Shown as Figure 6a Schematic diagram of the three-dimensional structure of the middle water guide layer.

[0035] Figure 7b Shown as Figure 6b Schematic diagram of the three-dimensional structure of the middle water guide layer.

[0036] Figure 8 Shown as the schematic diagram of the three-dimensional structure of the conductive bar in Embodiment 1 of the present invention.

[0037] Figure 9 Shown as the side view structure diagram of the flow field plate wrapped with the conductive bar in Embodiment 1 of the present invention.

[0038] Figure 10 Shown as the schematic diagram of the three-dimensional structure of the membrane frame in Embodiment 1 of the present invention.

[0039] Figure 11 Shown as the top view structure diagram of the membrane frame in Embodiment 1 of the present invention.

[0040] Figure 12 Shown as the bottom view structure diagram of the membrane frame in Embodiment 1 of the present invention.

[0041] Figure 13 Shown as the exploded structure diagram of the membrane frame in Embodiment 1 of the present invention.

[0042] Figure 14 Shown as the schematic diagram of the water and gas flow direction on the oxygen evolution side in Embodiment 1 of the present invention.

[0043] Figure 15 Shown as the top view structure diagram of the pressure membrane ring in Embodiment 1 of the present invention.

[0044] Figure 16 Shown as the working schematic diagram of the high-pressure electrolytic cell with an elastic flow field structure in Embodiment 1 of the present invention.

[0045] Figure 17 Shown as the exploded structure diagram of the multi-stage high-pressure electrolytic cell in Embodiment 2 of the present invention.

[0046] Figure 18 Shown as Figure 17 Combined three-dimensional structure schematic diagram of

[0047] Element number description

[0048] 100 Upper end plate

[0049] 101 Second bolt hole

[0050] 200 Upper insulating plate

[0051] 300 Upper electrode plate

[0052] 400 Membrane Frame

[0053] 401 First Sealing Ring

[0054] 402 Second Sealing Ring

[0055] 403 Third Sealing Ring

[0056] 404 Fourth Sealing Ring

[0057] 405 Fifth Sealing Ring

[0058] 406 Up-Flow Channel Groove

[0059] 407 Down-Flow Channel Groove

[0060] 408 Accommodation Chamber

[0061] 500 Composite Flow Field Structure

[0062] 501 Membrane Electrode

[0063] 502 Up-Flow Field Structure

[0064] 503 Down-Flow Field Structure

[0065] 504 Flow Field Plate

[0066] 05041 Up-Flow Field Plate

[0067] 05042 Down-Flow Field Plate

[0068] 5041 Horizontal Groove

[0069] 5042 Vertical Groove

[0070] 5043 Groove Bar

[0071] 505 Water Guide Layer

[0072] 05051 Upper Water Guide Layer

[0073] 05052 Lower Water Guide Layer

[0074] 5051 Water Guide Groove

[0075] 5052 Flat Plate

[0076] 5053 Rib

[0077] 5054 Water Guide Plate

[0078] 5055 Water Guide Long Hole

[0079] 506 Conductive Bar

[0080] 507 Membrane Pressing Ring

[0081] 5071 Fine groove

[0082] 5072 Edge groove

[0083] 600 Lower pole plate

[0084] 700 Lower insulating plate

[0085] 800 Lower end plate

[0086] 801 First bolt hole

[0087] 01 Oxygen-water inlet and outlet

[0088] 02 Hydrogen-water inlet and outlet

[0089] 03 Water-vapor inlet and outlet joint

[0090] 04 Water-vapor inlet and outlet gasket

[0091] 05 Bolt

[0092] 06 Nut

[0093] 07 Belleville spring

[0094] 08 Hydrogen tank

[0095] 09 Oxygen tank

[0096] 10 High-pressure electrolytic cell Specific embodiments

[0097] The following specific embodiments illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0098] Please refer to Figures 1 to 18 . It should be noted that the structures, ratios, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those skilled in the art to understand and read, and are not used to limit the limiting conditions under which the present invention can be implemented. Therefore, they do not have technical essence. Any modification of the structure, change of the ratio relationship, or adjustment of the size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope that can be covered by the technical content disclosed in the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle", and "one" cited in this specification are only for the convenience of clear description and are not used to limit the scope under which the present invention can be implemented. The change or adjustment of their relative relationships, without substantial change in the technical content, should also be regarded as the scope within which the present invention can be implemented.

[0099] Example 1

[0100] Refer to Figure 1 、Figure 2 , the present invention provides a high-pressure electrolytic cell with an elastic flow field structure. The high-pressure electrolytic cell 10 includes a lower end plate 800, a lower insulating plate 700, a lower electrode plate 600, a composite flow field unit, an upper electrode plate 300, an upper insulating plate 200, and an upper end plate 100 stacked upward in sequence; wherein, a plurality of first bolt holes 801 are formed at the edge of the lower end plate 800, and the upper surface of the lower end plate 800 is flat; the lower insulating plate 700 is stacked above the lower end plate 800; the lower electrode plate 600 is stacked above the lower insulating plate 700; the composite flow field unit is stacked above the lower electrode plate 600. The composite flow field unit includes a membrane frame 400 and a composite flow field structure 500. The membrane frame 400 has a receiving cavity 408, and the composite flow field structure 500 is disposed in the receiving cavity 408. The composite flow field structure 500 includes a lower flow field structure 503, a membrane electrode 501, and an upper flow field structure 502 stacked upward in sequence. The lower flow field structure 503 and the upper flow field structure 502 are both elastic in a direction perpendicular to the surface of the membrane electrode 501. A lower water storage and exhaust cavity is provided on a surface of the lower flow field structure 503 facing away from the membrane electrode 501, and an upper water storage and exhaust cavity is provided on a surface of the upper flow field structure 502 facing away from the membrane electrode 501; the upper electrode plate 300 is located above the composite flow field unit; the upper insulating plate 200 is located above the upper electrode plate 300, and the upper end plate 100 is located above the upper insulating plate 200, and a plurality of second bolt holes 101 corresponding to the first bolt holes 801 of the bolt 05 are provided at the edge. The bolt 05 fixedly connects the upper end plate 100 and the lower end plate 800 through the first bolt holes 801 of the bolt 05 and the second bolt holes 101; and a plurality of connected oxygen-water inlets and outlets 01 and a plurality of connected hydrogen-water inlets and outlets 02 are provided at the edges of the membrane frame 400, the upper electrode plate 300, the upper insulating plate 200, and the upper end plate 100. The upper water storage and exhaust cavity is communicated with the oxygen-water inlets and outlets 01, and the lower water storage and exhaust cavity is communicated with the hydrogen-water inlets and outlets 02.

[0101] Specifically, when the traditional PEM electrolyzer operates under high pressure, due to the lack of elasticity in the flow field structure, when there is a very high pressure on one side of the membrane electrode 501, such as the hydrogen side, the flow field on the oxygen side is compressed, and the hydrogen side expands. However, the inelastic flow field on the hydrogen side cannot compensate for this expansion. As a result, the pressing force of the flow field on the hydrogen side is greatly reduced, leading to a significant reduction in the contact points between the flow field on the hydrogen side, the titanium electrode, and the membrane electrolysis, and an increase in resistance, seriously deteriorating the performance of the electrolyzer. Usually, the efficiency of the electrolyzer is reduced by more than 20%. In this embodiment, the traditional rigid flow field composed of titanium felt, titanium mesh, and grooved plates is replaced by a downstream flow field structure 503 and an upstream flow field structure 502 that are both elastic in the direction perpendicular to the surface of the membrane electrode 501, solving the problem that when the high-pressure electrolyzer 10 is in use, the pressing force between the flow field and the plate decreases due to permanent compression deformation, resulting in a reduction in electrical contact points and an increase in contact resistance, thus reducing the efficiency of the electrolyzer. At the same time, a lower water storage and exhaust cavity is provided on the side of the downstream flow field structure 503 facing away from the membrane electrode 501, and an upper water storage and exhaust cavity is provided on the side of the upstream flow field structure 502 facing away from the membrane electrode 501. Moreover, the upper water storage and exhaust cavity is communicated with the oxygen-water inlet and outlet 01, and the lower water storage and exhaust cavity is communicated with the hydrogen-water inlet and outlet 02. Therefore, the lower water storage and exhaust cavity and the upper water storage and exhaust cavity play a good buffering role, greatly improving the efficiency of the water and gas exchange between the electrolyzer and the outside, and providing good conditions for water flow heat dissipation and gas discharge.

[0102] In the traditional electrolyzer structure, due to the difficulty in ensuring the flatness of each component during actual processing, after the components are stacked and pressed, only some areas may fit well and transmit pressure effectively, resulting in insufficient effective contact area and excessive contact resistance. In the specific embodiment of the present invention, the downstream flow field structure 503 and the upstream flow field structure 502 with elastic structures can well compensate for the flatness error of the components and improve the performance of electrical contact.

[0103] Specifically, the membrane electrode 501 is usually formed by spraying a positive electrode catalyst layer and a negative electrode catalyst layer on the opposite two surfaces of the proton exchange membrane. The downstream flow field structure 503, the membrane electrode 501, and the upstream flow field structure 502 are stacked in sequence.

[0104] Specifically, the bolt 05 sequentially passes through the first bolt 05 hole 801 and the second bolt 05 hole 101 and is fixedly connected to the nut 06. Moreover, a disc spring 07 is provided between the bolt 05 and the nut 06. Among them, a single disc spring 07 can be provided, or multiple disc springs 07 can be provided in series. Regarding the specific number of disc springs 07, no excessive limitation is made here.

[0105] Specifically, an inlet and outlet water and gas joint 03 communicating with the oxygen-water inlet and outlet 01 and the hydrogen-water inlet and outlet 02 is further provided in the high-pressure electrolyzer 10. An inlet and outlet water and gas gasket 04 is also provided at the connection between the inlet and outlet water and gas joint 03 and the oxygen-water inlet and outlet 01 and the hydrogen-water inlet and outlet 02 on the upper plate 300.

[0106] As an example, the lower flow field structure 503 and the upper flow field structure 502 both include a flow field plate 504 (including a lower flow field plate 05042 located at the lower flow field structure 503 and an upper flow field plate 05041 located at the upper flow field structure 502), and the flow field plate 504 (including the lower flow field plate 05042 located at the lower flow field structure 503 and the upper flow field plate 05041 located at the upper flow field structure 502) is provided with a plurality of transverse grooves 5041 and a plurality of vertical grooves 5042, each transverse groove 5041 penetrates the flow field plate 504 (including the lower flow field plate 05042 located at the lower flow field structure 503 and the upper flow field plate 05041 located at the upper flow field structure 502). The upper and lower surfaces of the upper flow field plate 05041 located in the upper flow field structure 502 are arranged parallel to each other, and the vertical grooves 5042 are opened on the side of the flow field plate 504 (including the lower flow field plate 05042 located in the lower flow field structure 503 and the upper flow field plate 05041 located in the upper flow field structure 502) away from the membrane electrode 501, and are intersected with the transverse grooves 5041; the multiple transverse grooves 5041 and the vertical grooves 5042 in the upper flow field structure 502 enclose an upper water storage and exhaust cavity, and the multiple transverse grooves 5041 and the vertical grooves 5042 in the lower flow field structure 503 enclose a lower water storage and exhaust cavity.

[0107] Specifically, the flow field plate 504 (including the lower flow field plate 05042 located at the lower flow field structure 503 and the upper flow field plate 05041 located at the upper flow field structure 502) is a multi-layer laminated composite structure, and has elasticity in the direction perpendicular to the surface of the membrane electrode 501; Figure 5 It is a schematic diagram of the three-dimensional structure of the flow field plate 504, in which the transverse groove 5041 and the vertical groove 5042 are cross-connected. Preferably, the transverse groove 5041 and the vertical groove 5042 are vertically arranged on the spatial plane; and the width and depth of the transverse groove 5041 and the vertical groove 5042, as well as the thickness of the flow field plate 504 can be much larger than the combination of the traditional engraved flow channel and the titanium mesh, so that the flow resistance is greatly reduced, which greatly improves the water-gas exchange of the high-pressure electrolytic cell 10 in this embodiment; preferably, the width of the transverse groove 5041 is 0.2-5 mm (for example, 0.2 mm, 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, etc.).

[0108] As an example, a water guiding layer 505 (including a lower water guiding layer 05052 located in the lower flow field structure 503 and an upper water guiding layer 05051 located in the upper flow field structure 502) is further provided between the flow field plate 504 (including a lower flow field plate 05042 located in the lower flow field structure 503 and an upper flow field plate 05041 located in the upper flow field structure 502) and the membrane electrode 501. The water guiding layer 505 (including the lower water guiding layer 05052 located in the lower flow field structure 503 and the upper water guiding layer 05051 located in the upper flow field structure 502) is adjacent to one side of the flow field plate 504 (including the lower flow field plate 05042 located in the lower flow field structure 503 and the upper flow field plate 05041 located in the upper flow field structure 502), and is provided with a plurality of water guiding grooves 5051. The plurality of water guiding grooves 5051 are arranged in parallel, and the water guiding grooves 5051 intersect with the transverse grooves 5041 on the adjacent flow field plate 504 (including the lower flow field plate 05042 located in the lower flow field structure 503 and the upper flow field plate 05041 located in the upper flow field structure 502) in space.

[0109] Specifically, referring to Figure 3 and Figure 4 , the composite flow field structure 500 includes a lower flow field plate 05042, a lower water guiding layer 05052, a membrane electrode 501, an upper water guiding layer 05051, and an upper flow field plate 05041 that are stacked upward in sequence. That is, the lower water guiding layer 05052 and the lower flow field plate 05042 are combined into the lower flow field structure 503. When the lower flow field structure 503 is on the hydrogen evolution side, the evolved hydrogen and water pass through the porous lower water guiding layer 05052, enter the water guiding grooves 5051, and then enter the transverse grooves 5041 and vertical grooves 5042 on the lower flow field plate 05042. Similarly, the upper water guiding layer 05051 and the upper flow field plate 05041 are combined into the upper flow field structure 502. The oxygen evolved from the upper flow field structure 502 passes through the porous upper water guiding layer 05051, enters the water guiding grooves 5051, and then enters the transverse grooves 5041 and vertical grooves 5042 on the upper flow field plate 05041. In addition, referring to Figure 3 and Figure 4 , the size of the upper water guiding layer 05051 is the same as the size of the membrane electrode 501, the size of the lower water guiding layer 05051 is the same as the sizes of the upper flow field plate 05041 and the lower flow field plate 05042, and the size of the upper water guiding layer 05051 is larger than the size of the lower water guiding layer 05052. The high-pressure electrolytic cell in the present invention is mainly used for producing high-pressure hydrogen. When the hydrogen evolution side is under pressure, the area of the water guiding layer 505 on the oxygen evolution side is larger than the area of the water guiding layer 505 on the hydrogen evolution side. The upper water guiding layer 05051 on the oxygen evolution side can provide reliable support for the membrane electrode 501 and prevent the membrane electrode 501 from being damaged by being embedded in the gap.

[0110] As an example, the water guiding layer 505 includes a flat plate 5052 and a water guiding component. The water guiding component is arranged on the flat plate, and water guiding grooves 5051 are formed on the water guiding component.

[0111] Specifically, the flat plate 5052 is a titanium foam or titanium felt with a certain porosity and can permeate water; in a specific embodiment, refer to Figure 6a , the water guiding assembly includes a plurality of ribs 5053, and the plurality of ribs 5053 are arranged in parallel on the flat plate 5052, and a water guiding groove 5051 is formed between two adjacent ribs 5053.

[0112] In other specific embodiments, refer to Figure 7a , the water guiding layer 505 can be an integral structure, and the water guiding layer 505 includes an integral structure formed by combining the flat plate 5052 and a plurality of ribs 5053.

[0113] Specifically, in other embodiments, refer to 6b, the water guiding assembly includes a water guiding plate 5054, and a plurality of water guiding long holes 5055 are provided on the water guiding plate 5054, and each water guiding long hole 5055 penetrates through the upper and lower surfaces of the water guiding plate 5054 and is arranged in parallel with each other; the water guiding plate 5054 in the water guiding assembly is arranged on the flat plate 5052, and a water guiding groove 5051 is formed between the water guiding long holes 5055 and the flat plate 5052; wherein, the water guiding plate 5054 is a titanium plate, and a plurality of water guiding long holes 5055 are formed in parallel on the titanium plate, thereby forming a composite water guiding layer 505, refer to Figure 7b is a schematic three-dimensional structure diagram of the composite water guiding layer 505, which further enhances the reliability of the overall structure of the high-pressure electrolytic cell in the present invention.

[0114] Preferably, the width of the water guiding groove 5051 is 0.2 - 5 mm (such as 0.2 mm, 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, etc.); in addition, the water guiding groove 5051 and the transverse groove 5041 on the adjacent flow field plate 504 are arranged to intersect in space, preferably, the water guiding groove 5051 and the transverse groove 5041 on the adjacent flow field plate are arranged perpendicular to each other in space.

[0115] As an example, a plurality of transverse grooves 5041 divide the flow field plate 504 into several strip-shaped bars 5043, and conductive strips 506 are wrapped on the upper and lower surfaces of each strip-shaped bar 5043.

[0116] Refer to Figure 8 , the conductive strip 506 is a U-shaped structure formed by bending a thin sheet, and has elasticity in the direction perpendicular to the surface of the membrane electrode 501. Of course, the conductive strip 506 can also be of other shapes, as long as it can ensure that the upper and lower surfaces of the strip-shaped bar 5043 can be covered and wrapped. Regarding the specific shape of the conductive strip 506, no excessive limitation is made here; regarding the thickness of the thin sheet of the conductive strip 506, it is necessary to have a sufficient conductive interface, and the thickness of the thin sheet of the conductive strip 506 is preferably 0.05 - 2 mm (such as 0.05 mm, 0.1 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, etc.).

[0117] Refer to Figure 9 , the conductive strip 506 wraps the upper and lower surfaces of the slat 5043. After the slats 5043 wrapped with the conductive strip 506 on the upstream flow field plate 05041 are stacked, they are respectively in close contact with the upper plate 300 and the upper water guiding layer 05051, so that the upper plate 300 and the upper water guiding layer 05051 form a reliable electrical connection through the conductive strip 506; similarly, the slats 5043 wrapped with the conductive strip 506 on the downstream flow field plate 05042 are stacked and in close contact with the lower plate 600 and the lower water guiding layer 05052 after stacking, so that the lower plate 600 and the lower water guiding layer 05052 form a reliable electrical connection through the conductive strip 506; in addition, the function of the slat 5043 is to transmit the pressing force, so that there is a certain contact pressure between adjacent components, so as to maintain good electrical contact.

[0118] As an example, a plurality of upstream flow channels 406 are provided on one side of the membrane frame 400 adjacent to the upper plate 300, and each upstream flow channel 406 is correspondingly communicated with the oxygen-water inlet and outlet 01 on the membrane frame; a plurality of downstream flow channels 407 are provided on one side of the membrane frame 400 adjacent to the lower plate 600, and each downstream flow channel 407 is correspondingly communicated with the hydrogen-water inlet and outlet 02 on the membrane frame.

[0119] Specifically, refer to Figures 10 to 12 , two upstream flow channels 406 are provided, and the two upstream flow channels 406 are arranged diagonally. Two downstream flow channels 407 are also provided, and the two downstream flow channels 407 are arranged diagonally; of course, in other embodiments, the number of upstream flow channels 406 and downstream flow channels 407 can also be set to three or more, which will not be overly restricted here; refer to Figure 14 is a schematic diagram of the water and gas flow direction on the oxygen evolution side. An oxygen-side common flow channel is formed between the inlet and outlet water and gas joint 03, the oxygen-water inlet and outlet 01, the upstream flow channel 406, the horizontal groove 5041 and the vertical groove 5042 of the upstream flow field plate 05041.

[0120] As an example, a membrane pressing ring 507 is provided on the circumferential edge of the membrane electrode 501 protruding outward from the flow field plate 504. The membrane pressing ring 507 is circumferentially arranged around the outer edge of the flow field plate 504, and a plurality of grooves are formed on the membrane pressing ring 507. The plurality of grooves are communicated with the upper water storage and exhaust cavity and are also communicated with the upstream flow channel 406.

[0121] Specifically, refer to Figure 4 for the three-dimensional structure schematic diagram of the composite flow field structure 500 in. The size of the upper water guiding layer 05051 is the same as that of the membrane electrode 501. The edges of the membrane electrode 501 and the upper water guiding layer 05051 both protrude outward from the upstream flow field plate 05041 and the downstream flow field structure 503; refer to Figure 15It is a view of the film pressing ring 507. The outer ring of the film pressing ring 507 is as large as the membrane electrode 501, and the inner ring just encloses the outer edge of the upstream flow field plate 05041. A plurality of grooves communicating with the upper water storage and exhaust cavity are formed on the film pressing ring 507, and the grooves also communicate with the upstream flow channel groove 406, so that the upper water storage and exhaust cavity, the grooves and the upstream flow channel groove 406 communicate with each other; specifically, regarding the structure and setting method of the grooves, no excessive restrictions are made here. In this embodiment, a plurality of fine grooves 5071 are evenly arranged between the outer ring and the inner ring of the groove, and the fine grooves 5071 penetrate through the edge of the inner ring. Side grooves 5072 are circumferentially arranged adjacent to the outer ring of the fine grooves 5071, and the side grooves 5072 just communicate with the upstream flow field groove.

[0122] As an example, a first sealing ring 401 is arranged in the accommodation cavity 408. The first sealing ring 401 is located below the membrane electrode 501 and surrounds the circumferential edge of the membrane electrode 501.

[0123] As an example, a second sealing ring 402 is arranged at each oxygen and water inlet / outlet 01 on the membrane frame. The second sealing ring 402 is located on the side of the membrane frame 400 adjacent to the downstream flow field structure 503; a third sealing ring 403 is arranged at each hydrogen and water inlet / outlet 02 on the membrane frame. The third sealing ring 403 is located on the side of the membrane frame 400 adjacent to the upstream flow field structure 502.

[0124] Specifically, refer to Figure 10 It is a three-dimensional structure schematic diagram of the membrane frame 400. Since the upstream flow channel groove 406 and the downstream flow channel groove 407 are respectively located on the upper and lower surfaces of the membrane frame 400, the water, oxygen flowing in the upstream flow channel groove 406 and the water, hydrogen flowing in the downstream flow channel groove 407 are isolated from each other under the sealing of the membrane electrode 501 and the first sealing ring 401, the second sealing ring 402, and the third sealing ring 403, so as to realize the separation of hydrogen and oxygen.

[0125] Refer to Figure 13 , in this embodiment, a circumferential lower edge groove is formed at the edge of the side of the membrane frame 400 adjacent to the downstream flow field structure 503, and a fourth sealing ring 404 is arranged in the lower edge groove. A circumferential upper edge groove is formed at the edge of the side of the membrane frame 400 adjacent to the upstream flow field structure 502, and a fifth sealing ring 405 is arranged in the upper edge groove.

[0126] Refer to Figure 16The schematic diagram of the working of the high-pressure electrolyzer with elastic flow field structure in this embodiment is as follows: the high-pressure electrolyzer 10 is placed horizontally with the oxygen-evolving side on the top; the water tank (oxygen tank 09 and hydrogen tank 08) is placed above the high-pressure electrolyzer 10; the hydrogen-water inlet and outlet 02 of the high-pressure electrolyzer 10 is directly adjacent to the hydrogen tank 08; the oxygen-water inlet and outlet 01 is directly connected to the oxygen tank 09; a DC voltage is applied to the upper electrode plate 300 and the lower electrode plate 600; at this time, hydrogen and oxygen are respectively precipitated on both sides of the membrane electrode 501; the precipitated oxygen quickly passes through the loose upper water-conducting layer 05051, enters the water-conducting groove 5051 of the upper water-conducting layer 05051, the horizontal groove 5041 and the vertical groove 5042 on the upper flow field plate 05041, the groove on the film pressing ring 507, and then passes through the upper flow field plate 05041 on the membrane frame 400; The channel groove 406 finally merges into the common flow channel formed by the superposition of the oxygen-water inlet and outlet 01 of the membrane frame 400, the oxygen-water inlet and outlet 01 of the upper electrode plate 300, and the inlet and outlet water and gas joint 03, and then enters the oxygen tank 09. The water in the oxygen tank 09 is replenished to the surface of the membrane electrode 501 in the opposite flow direction to the oxygen; similarly, the precipitated hydrogen and water pass through the loose lower water-conducting layer 05052, enter the water-conducting groove 5051 of the lower water-conducting layer 05052, the horizontal groove 5041 and the vertical groove 5042 of the lower flow field plate 05042, and then pass through the lower flow channel groove 407 on the membrane frame 400, and finally merge into the common flow channel formed by the superposition of the hydrogen-water inlet and outlet 02 of the membrane frame 400, the hydrogen-water inlet and outlet 02 of the upper electrode plate 300, and the inlet and outlet water and gas joint 03, and then enter the hydrogen tank 08.

[0127] Specifically, in this embodiment, by adjusting the thickness of the flow field plate 504 (including the lower flow field plate 05042 located at the lower flow field structure 503 and the upper flow field plate 05041 located at the upper flow field structure 502) and the width of the transverse groove 5041 and the vertical groove 5042, the volume of the pore part on the flow field plate 504 (including the lower flow field plate 05042 located at the lower flow field structure 503 and the upper flow field plate 05041 located at the upper flow field structure 502) can be made large enough so that the exhausted gas can have enough buffer storage space, and the water entering the oxygen analysis side from the water tank can be stored under the action of gravity. The lower water storage and exhaust chamber is retained at the lower part of the upper water storage and exhaust chamber, so that the oxygen evolution surface of the entire membrane electrode 501 is always immersed in water, and the electrolysis reaction is more evenly distributed on the membrane electrode 501, which completely solves the water shortage problem of the membrane electrode 501 and realizes the pumpless operation of the high-pressure electrolyzer 10 in this embodiment, which greatly simplifies the system complexity and improves the system reliability; the structure of the lower water storage and exhaust chamber on the hydrogen evolution side is similar to that on the oxygen evolution side. Although the hydrogen evolution side does not need to be replenished with water, the lower water storage and exhaust chamber is set on the hydrogen evolution side. It can more effectively utilize the flow of water to take away the reaction heat and prevent the membrane electrode 501 from overheating and failure.

[0128] Performance Testing

[0129] The high-pressure electrolytic cell with an elastic flow field structure in this embodiment is subjected to a working test. The pressure on the hydrogen evolution side is 3.5 Mpa, and the pressure on the oxygen evolution side is 3 Mpa. At a current density of 1.5 A·cm –2 it operates stably without a pump for more than five thousand hours and is still operating stably; and under the same conditions, the efficiency of the high-pressure electrolytic cell 10 in this embodiment is more than 18% higher than that of the traditional electrolytic cell, and the overall efficiency of the entire high-pressure electrolytic cell 10 is increased by more than 20%. Among them, the traditional electrolytic cell is formed by tightly pressing together multiple layers of components such as titanium electrode plates, titanium felts, titanium meshes, and proton exchange membrane electrodes 501 coated with catalysts, hydrogen-oxygen sealing frames, etc. in series by two end plates through bolts 05. A water pump that operates continuously is also required during operation. The specific structure will not be elaborated here.

[0130] Embodiment 2

[0131] This embodiment provides another high-pressure electrolytic cell with an elastic flow field structure. The main difference between this embodiment and Embodiment 1 is that in Embodiment 1, one upper electrode plate 300 and one composite flow field unit are provided, while in this embodiment, both the upper electrode plate 300 and the composite flow field unit are multiple, and the upper electrode plate 300 and the composite flow field unit are alternately arranged to form a multi-stage high-pressure electrolytic cell in multi-stage series. The structures of other components are the same as those in Embodiment 1 and will not be elaborated here.

[0132] Referring to Figure 17 and Figure 18 , the high-pressure electrolytic cell with an elastic flow field structure in this embodiment includes three upper electrode plates 300 and three composite flow field units, and the upper electrode plates 300 and the composite flow field units are alternately arranged; since the composite flow field unit includes a membrane frame 400 and a composite flow field structure 500, the composite flow field structure 500 is arranged in the accommodation cavity 408 of the membrane frame 400. The composite flow field structure 500 includes a downstream flow field structure 503, a membrane electrode 501, and an upstream flow field structure 502. The downstream flow field structure 503 is the hydrogen evolution side, and the upstream flow field structure 502 is the oxygen evolution side. That is, the membrane frame 400 is equivalent to the sealing frame of the composite flow field structure 500. In this embodiment, the hydrogen evolution side and the oxygen evolution side are combined into one membrane frame, so that when multiple composite flow field units in the multi-stage high-pressure electrolytic cell are connected in series, the sealing difficulty is greatly reduced, and the hidden danger of seal leakage is reduced.

[0133] In summary, the present invention adopts an elastic upstream flow field structure, a downstream flow field structure, and conductive strips coated on the upstream flow field structure and the downstream flow field structure, which solves the problems that in the long-term use of a high-pressure electrolytic cell, the pressing force between the flow field and the electrode plate decreases, the number of electrical contact points decreases, and the contact resistance increases due to permanent compression deformation, resulting in a decrease in the efficiency of the high-pressure electrolytic cell. At the same time, the transverse grooves and vertical grooves on the flow field plate together form a large-volume water storage and exhaust cavity, which provides more space for water vapor buffering and exchange per unit area, realizes the pump-free operation of the high-pressure electrolytic cell, and the elastic composite flow field structure maintains the stability of electrical contact, greatly improving the working efficiency of the electrolytic cell under high gas pressure. In addition, the water storage and exhaust cavity has a good buffering effect, greatly reducing the flow resistance and greatly improving the efficiency of water vapor exchange between the electrolytic cell and the outside, thus providing good conditions for water flow heat dissipation and gas discharge, and also greatly reducing the cost and weight compared with the traditional electrolytic cell. Therefore, the present invention effectively overcomes various disadvantages in the prior art and has high industrial utilization value.

[0134] The above embodiments are only illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes completed by those with ordinary knowledge in the technical field without departing from the spirit and technical idea disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A high-pressure electrolytic cell with an elastic flow field structure, characterized in that, The high-pressure electrolytic cell includes a lower end plate, a lower insulating plate, a lower electrode plate, a composite flow field unit, an upper electrode plate, an upper insulating plate, and an upper end plate that are stacked upward in sequence; A plurality of first bolt holes are formed in the edge of the lower end plate, and the upper surface of the lower end plate is flat; The lower insulating plate is stacked above the lower end plate; The lower electrode plate is stacked above the lower insulating plate; The composite flow field unit is stacked above the lower electrode plate. The composite flow field unit includes a membrane frame and a composite flow field structure. The membrane frame has an accommodation cavity, and the composite flow field structure is arranged in the accommodation cavity. The composite flow field structure includes a lower flow field structure, a membrane electrode, and an upper flow field structure that are stacked upward in sequence. The lower flow field structure and the upper flow field structure are both elastic in a direction perpendicular to the surface of the membrane electrode. A lower water storage and exhaust cavity is arranged on a surface of the lower flow field structure facing away from the membrane electrode, and an upper water storage and exhaust cavity is arranged on a surface of the upper flow field structure facing away from the membrane electrode; The upper electrode plate is located above the composite flow field unit; The upper insulating plate is located above the upper electrode plate; the upper end plate is located above the upper insulating plate, and a plurality of second bolt holes corresponding to the first bolt holes are arranged at the edge. The bolts fixedly connect the upper end plate and the lower end plate through the first bolt holes and the second bolt holes; Moreover, a plurality of connected oxygen-water inlets and outlets and a plurality of connected hydrogen-water inlets and outlets are arranged at the edges of the membrane frame, the upper electrode plate, the upper insulating plate, and the upper end plate. The upper water storage and exhaust cavity is communicated with the oxygen-water inlets and outlets, and the lower water storage and exhaust cavity is communicated with the hydrogen-water inlets and outlets.

2. The high-pressure electrolytic cell with an elastic flow field structure according to claim 1, wherein: Both the lower flow field structure and the upper flow field structure include flow field plates. A plurality of horizontal grooves and a plurality of vertical grooves are arranged on the flow field plates. Each horizontal groove penetrates the upper and lower surfaces of the flow field plate and is arranged in parallel. The vertical grooves are formed on a side of the flow field plate facing away from the membrane electrode and intersect with the horizontal grooves; a plurality of the horizontal grooves and vertical grooves in the upper flow field structure enclose the upper water storage and exhaust cavity, and a plurality of the horizontal grooves and the vertical grooves in the lower flow field structure enclose the lower water storage and exhaust cavity.

3. The high-pressure electrolytic cell with an elastic flow field structure according to claim 2, characterized in that: A water guiding layer is further arranged between the flow field plate and the membrane electrode. A plurality of water guiding grooves are arranged on a surface of the water guiding layer adjacent to the flow field plate. The plurality of water guiding grooves are arranged in parallel, and the water guiding grooves intersect with the horizontal grooves on the adjacent flow field plate in space.

4. The high-pressure electrolytic cell with an elastic flow field structure according to claim 3, characterized in that: The water guiding layer includes a flat plate and a water guiding component. The water guiding component is arranged on the flat plate, and the water guiding grooves are formed on the water guiding component.

5. The high-pressure electrolytic cell with an elastic flow field structure according to claim 3, characterized in that: A plurality of the horizontal grooves divide the flow field plate into several strip-shaped grooves, and conductive strips are wrapped on the upper and lower surfaces of each strip-shaped groove.

6. The high-pressure electrolytic cell with an elastic flow field structure according to claim 2, wherein: A plurality of upper flow channel grooves are formed on a surface of the membrane frame adjacent to the upper electrode plate. Each upper flow channel groove is correspondingly and communicatively arranged with the oxygen-water inlets and outlets on the membrane frame one by one; a plurality of lower flow channel grooves are formed on a surface of the membrane frame adjacent to the lower electrode plate. Each lower flow channel groove is correspondingly and communicatively arranged with the hydrogen-water inlets and outlets on the membrane frame one by one.

7. The high-pressure electrolytic cell with an elastic flow field structure according to claim 6, characterized in that: A pressure membrane ring is provided at the circumferential edge of the membrane electrode, protruding outward from the flow field plate. The pressure membrane ring is circumferentially disposed around the outer edge of the flow field plate, and a plurality of grooves are formed on the pressure membrane ring. The plurality of grooves communicate with each other and with the upper water storage and exhaust cavity, and also communicate with the upper flow channel groove.

8. The high-pressure electrolytic cell with an elastic flow field structure according to claim 1, characterized in that: A first sealing ring is provided in the accommodation cavity. The first sealing ring is located below the membrane electrode and is disposed around the circumferential edge of the membrane electrode.

9. The high-pressure electrolytic cell with an elastic flow field structure according to claim 1, characterized in that: A second sealing ring is provided at each oxygen and water inlet / outlet on the membrane frame. The second sealing ring is located on the side of the membrane frame adjacent to the downstream flow field structure. A third sealing ring is provided at each hydrogen and water inlet / outlet on the membrane frame. The third sealing ring is located on the side of the membrane frame adjacent to the upstream flow field structure.

10. The high-pressure electrolytic cell with an elastic flow field structure according to any one of claims 1 to 9, characterized in that: The upper electrode plates and the composite flow field units are both multiple, and the upper electrode plates and the composite flow field units are alternately arranged to form a multi-stage series-connected multi-stage high-voltage electrolytic cell.

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