Full-watershed AEM electrolytic cell with flexible supporting structure

Abstract

The utility model discloses a full-watershed AEM electrolytic bath with a flexible supporting structure, and belongs to the technical field of water electrolysis. Comprising a flexible supporting porous transmission layer and an integrated membrane electrode, the flexible supporting porous transmission layer and the integrated membrane electrode are both installed between two full-watershed bipolar plates, and the outer sides of the full-watershed bipolar plates and the outer side of the integrated membrane electrode are connected with a cathode end pressing plate and an anode end pressing plate through positioning holes respectively. The cathode end pressing plate and the anode end pressing plate are connected through a bolt hole, and the back of the cathode end pressing plate is provided with an end pressing plate inlet and outlet groove box. According to the utility model, an integrated structure is adopted, the assembly is convenient, the maintenance cost is low, large-scale batch production is facilitated, and industrialization is easier to realize. The problem that a flow field has a dead angle due to hole liquid inlet and hole gas outlet of a traditional bipolar plate is solved. The flow field distribution of the solution is improved, the liquid flow resistance is greatly reduced, the dispersion of the solution in the PTL is better, and the flow field is more regular than that of a traditional mode adopting a metal stretching net.

Description

Technical Field

[0001] The utility model relates to the technical field of electrolyzed water, in particular to an all-basin AEM electrolytic cell with a flexible support structure. Background Art

[0002] The bipolar plate and the porous transport layer (PTL) of the electrolytic cell for hydrogen production by electrolyzing water are both core components of the electrolytic cell, and their design structures directly determine the assembly difficulty of the electrolytic cell and the three-phase mass transfer state during the dynamic hydrogen production process. At present, most bipolar plates of AEM (anion exchange membrane AEM) electrolytic cells adopt the liquid inlet mode with small apertures, and the flow field of the electrolyte solution is mostly machined by a metal bipolar plate or etched by an acid solution. Today, when the AEM electrolyzed water hydrogen production technology and hydrogen production equipment have not been commercialized, most domestic manufacturers also focus on how to further improve the current density and hydrogen production efficiency. However, the liquid inlet, gas production mode, flow field distribution, and installation quality of the bipolar plate will also affect the temperature uniformity and electrolytic performance of the electrolytic cell, and even determine the service life of the electrolytic cell. At present, the small-aperture bipolar plate and flow channel have the following problems:

[0003] 1) The small-aperture liquid inlet and gas production of the bipolar plate will cause the gas resistance and liquid resistance of the bipolar plate to increase, and the electrolyte solution does not completely carry out mass transfer and heat transfer according to the designed flow channel. There are dead corners in the active area of the bipolar plate, resulting in local overheating, bubbles not being taken away in time, and the contact resistance increasing;

[0004] 2) The flow channel of the bipolar plate adopts the machining method, which has a long production time and high cost, and it is difficult to ensure the flatness of the bipolar plate by machining; while the flow channel of the bipolar plate adopts the acid solution etching process, which has a high cost and poor consistency of the flow channel depth;

[0005] 3) The flow channel of the bipolar plate has relatively strict requirements on the thickness of the membrane electrode. During the installation process, it is very difficult to control the contact degree between the membrane electrode and the flow channel of the bipolar plate through the processing accuracy, which will lead to inconsistent contact resistances between the internal components of the electrolytic cell and affect the hydrogen production voltage of the electrolytic cell. Summary of the Utility Model

[0006] The purpose of the utility model is to provide an all-basin AEM electrolytic cell with a flexible support structure, which solves the problem of dead corners in the flow field caused by the liquid inlet and gas outlet through holes of the traditional bipolar plate.

[0007] To achieve the above object, the utility model provides a full - basin AEM electrolyzer with a flexible support structure, which includes a flexible support porous transport layer and an integrated membrane electrode. The flexible support porous transport layer and the integrated membrane electrode are both installed between two full - basin bipolar plates. The outsides of the full - basin bipolar plates and the integrated membrane electrode are respectively connected to the cathode end plate and the anode end plate through positioning holes. The cathode end plate and the anode end plate are connected through bolt holes, and a end plate inlet - outlet trough box is arranged on the back of the cathode end plate.

[0008] Preferably, the flexible support porous transport layer includes two woven nickel meshes, and an elastic nickel mesh is installed between the two woven nickel meshes. The thickness of each woven nickel mesh is 0.2 - 0.4 mm, and the distance between the two woven nickel meshes is 0.5 - 1 mm.

[0009] Preferably, recessed structures are arranged at the centers of the front and back sides of the two full - basin bipolar plates. A cathode liquid outlet and a cathode liquid inlet are respectively arranged at the top and bottom of each recessed structure. Longitudinally arranged liquid inlet flow channel grooves are correspondingly arranged at the bottom of the cathode liquid outlet and the top of the cathode liquid inlet. The depth of the liquid inlet flow channel groove is 0.5 - 1 mm. An anode liquid outlet and an anode liquid inlet are respectively arranged on the left and right sides of the recessed structure.

[0010] Preferably, the full - basin bipolar plate is of a rectangular structure, and its material is carbon steel nickel - plated material. The recessed structure is of a square structure.

[0011] Preferably, the integrated membrane electrode is of a five - in - one structure, which is arranged in sequence as a polyether ether ketone sealing frame PEEK, a catalyst diffusion layer GDL, an anion exchange membrane AEM, a catalyst diffusion layer GDL, and a polyether ether ketone sealing frame PEEK. The above structures are all adhesively connected by polytetrafluoroethylene glue.

[0012] Preferably, the sizes of the polyether ether ketone sealing frame PEEK and the anion exchange membrane AEM are the same as the size of the full - basin bipolar plate, and the size of the catalyst diffusion layer GDL is the same as the size of the recessed structure.

[0013] Preferably, the thickness of the polyether ether ketone sealing frame PEEK is equal to the thickness of the recessed structure, and its expression is δ(double - layer PEEK + anion exchange membrane AEM)=δ(compressed double - layer GDL + anion exchange membrane AEM).

[0014] Preferably, cathode gas outlets are arranged on both the upper and lower sides of the cathode end plate, anode gas outlets are respectively arranged on the left and right sides of the cathode end plate, and a cathode power transmission plate is installed at the center of the bottom of the cathode end plate.

[0015] Preferably, an anode power transmission plate is installed at the center of the bottom of the anode end plate.

[0016] Preferably, the end pressure plate enters and exits the tank box, which is made of stainless steel, has a hollow structure inside, and the outlet is connected by a union joint.

[0017] Therefore, the present utility model adopts a full-flow AEM electrolyzer with the above structure and has the following beneficial effects:

[0018] (1) The electrolyte solution inlet and outlet channels are the full dimensions of the length and width of the bipolar plate, and the solution is in full contact with the bipolar plate without dead angles, which solves the problem of dead angles in the flow field caused by the traditional bipolar plate with hole inlet and hole outlet.

[0019] (2) The flexible support porous transport layer (PTL) can effectively elastically compensate for the thickness of the integrated membrane electrode. Due to its high elasticity characteristics, the requirements for the processing accuracy of the bipolar plate and the structural dimensions of the electrode are greatly reduced.

[0020] (3) The combination of the full-flow bipolar plate and the PTL significantly improves the flow field distribution of the solution, greatly reduces the liquid flow resistance, the dispersion of the solution in the PTL is better, and the flow field is more regular than the traditional method using a metal drawing mesh.

[0021] (4) The polyether ether ketone (PEEK) of the integrated membrane electrode frame is a material resistant to temperature and acid-base. At the same time, coating polytetrafluoroethylene glue on the PEEK can be tightly sealed with the full-flow bipolar plate, and the electrolyzer has better pressure resistance.

[0022] (5) The core components of the electrolyzer adopt an integrated structure, which is convenient for assembly, has low maintenance costs, is conducive to large-scale batch production, and is easier to industrialize.

[0023] The technical solution of the present utility model will be further described in detail below through the drawings and embodiments. Description of the Drawings

[0024] Figure 1 It is a schematic diagram of the overall structure of a full-flow AEM electrolyzer with a flexible support structure according to the present utility model;

[0025] Figure 2 It is a schematic diagram of the front structure of the flexible support porous transport layer of a full-flow AEM electrolyzer with a flexible support structure according to the present utility model;

[0026] Figure 3 It is a schematic diagram of the side structure of the flexible support porous transport layer of a full-flow AEM electrolyzer with a flexible support structure according to the present utility model;

[0027] Figure 4 It is a schematic diagram of the front structure of the full-flow bipolar plate of a full-flow AEM electrolyzer with a flexible support structure according to the present utility model;

[0028] Figure 5 Schematic front view of the integrated membrane electrode of a full-basin AEM electrolyzer with a flexible support structure according to the present invention;

[0029] Figure 6 Schematic front view of the cathode end plate of a full-basin AEM electrolyzer with a flexible support structure according to the present invention;

[0030] Figure 7 Schematic front view of the anode end plate of a full-basin AEM electrolyzer with a flexible support structure according to the present invention;

[0031] Figure 8 Schematic view of the structure of the end plate inlet / outlet tank of a full-basin AEM electrolyzer with a flexible support structure according to the present invention.

[0032] Reference numerals

[0033] 1. Woven nickel mesh; 2. Elastic nickel mesh; 3. Liquid inlet flow channel groove; 4. Positioning hole; 5. Cathode liquid inlet; 6. Cathode liquid outlet; 7. Anode liquid inlet; 8. Anode liquid outlet; 9. Anion exchange membrane AEM; 10. Sealing frame; 11. Catalyst diffusion layer GDL; 12. Bolt hole; 13. Cathode gas outlet; 14. Anode gas outlet; 15. Cathode power transmission plate; 16. Anode power transmission plate, 17. Concave structure, 101. Flexible support porous transport layer, 102. Full-basin bipolar plate, 103. Integrated membrane electrode, 104. End plate inlet / outlet tank, 105. Cathode end plate, 106. Anode end plate. Detailed implementation manners

[0034] The technical solutions of the present invention will be further described below with reference to the drawings and embodiments.

[0035] Unless otherwise defined, the technical terms or scientific terms used in the present invention should have the ordinary meanings understood by those of ordinary skill in the field to which the present invention belongs. The "first", "second" and similar terms used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. The terms such as "including" or "comprising" mean that the elements or objects appearing before the term cover the elements or objects listed after the term and their equivalents, without excluding other elements or objects. The terms such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The terms such as "upper", "lower", "left", "right" are only used to represent relative positional relationships, and when the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0036] Embodiment

[0037] As Figure 1-8 shown, the present utility model provides a full - basin AEM electrolyzer with a flexible support structure, including a flexible support porous transport layer 101 and an integrated membrane electrode 103. The flexible support porous transport layer 101 and the integrated membrane electrode 103 are both installed between two full - basin bipolar plates 102. The outer sides of the full - basin bipolar plates 102 and the integrated membrane electrode 103 are respectively connected to the cathode end plate 105 and the anode end plate 106 through positioning holes 4. The cathode end plate 105 and the anode end plate 106 are connected through bolt holes 12, and end plate inlet - outlet trough boxes 104 are arranged on the backs of the cathode end plates 105.

[0038] The flexible support porous transport layer 101 includes two woven nickel meshes 1, and an elastic nickel mesh 2 is installed between the two woven nickel meshes 1. The thickness of each woven nickel mesh 1 is 0.2 - 0.4 mm, and the distance between the two woven nickel meshes 1 is 0.5 - 1 mm.

[0039] Depression structures 17 are arranged at the centers of the front and back sides of the two full - basin bipolar plates 102. A cathode liquid outlet 6 and a cathode liquid inlet 5 are respectively arranged at the top and bottom of each depression structure 17. Longitudinally arranged liquid inlet flow channel grooves 3 are correspondingly arranged at the bottom of the cathode liquid outlet 6 and the top of the cathode liquid inlet 5. The depth of the liquid inlet flow channel grooves 3 is 0.5 - 1 mm. An anode liquid outlet 8 and an anode liquid inlet 7 are respectively arranged on the left and right sides of the depression structure 17.

[0040] The full - basin bipolar plate 102 is a rectangular structure, and its material is carbon steel nickel - plated material. The depression structure 17 is a square structure.

[0041] The integrated membrane electrode 103 is a five - in - one structure, which is arranged in sequence as a polyether ether ketone sealing frame PEEK, a catalyst diffusion layer GDL11, an anion exchange membrane AEM9, a catalyst diffusion layer GDL11, and a polyether ether ketone sealing frame PEEK. The above - mentioned structures are all adhesively connected with polytetrafluoroethylene glue.

[0042] The sizes of the polyether ether ketone sealing frame PEEK and the anion exchange membrane AEM9 are the same as those of the full - basin bipolar plate 102, and the size of the catalyst diffusion layer GDL11 is the same as that of the depression structure 17. This can not only ensure the stability and firmness of the ion membrane during installation and hydrogen production, but also enable the GDL and the catalyst to be all in the electrochemical catalytic environment.

[0043] The thickness of the polyether ether ketone sealing frame PEEK is equal to the thickness of the depression structure 17, and its expression is δ(double - layer PEEK + anion exchange membrane AEM)=δ(compressed double - layer GDL + anion exchange membrane AEM).

[0044] Cathode outlet ports 13 are provided on both the upper and lower sides of the cathode end pressing plate 105. Anode outlet ports 14 are respectively provided on the left and right sides of the cathode end pressing plate 105. A cathode power transmission plate 15 is installed at the center of the bottom of the cathode end pressing plate 105.

[0045] An anode power transmission plate 16 is installed at the center of the bottom of the anode end pressing plate 106.

[0046] The end pressing plate inlet and outlet trough box 104 is made of stainless steel, with a hollow structure inside, and the outlet is connected by a union. The design purpose of the end pressing plate inlet and outlet trough box 104 is to increase the flow field area at the inlet and outlet, thereby reducing the flow resistance and making the liquid more evenly dispersed before entering and leaving the electrolytic cell.

[0047] The present utility model provides a full-flow AEM electrolytic cell with a flexible support structure, and its overall integration process is as follows:

[0048] S1. The anode end pressing plate of the electrolytic cell is placed parallel on the installation base, so that all the screw hole positions are exposed. Insert the positioning pins, place a layer of polytetrafluoroethylene gasket for sealing, and then install it on the gasket along the positioning holes with the flow channel surface of the anode plate facing upwards. Subsequently, lay the flexible PTL and the first integrated membrane electrode;

[0049] S2. Start installing the first layer of full-flow bipolar plates, and then continue to place the flexible PTL and the second integrated membrane electrode, with the anode catalyst surface of the membrane electrode facing downwards and the cathode catalyst surface facing upwards;

[0050] S3. Install the second layer of full-flow bipolar plates, with the inlet and outlet positions consistent with the first layer, and then install the flexible PTL and the integrated membrane electrode in the above order;

[0051] S4. After installing the last layer of flexible PTL, place the cathode plate, lay the polytetrafluoroethylene sealing frame, then place the cathode end pressing plate, and finally perform screw tightening and airtightness detection on the electrolytic cell.

[0052] The present utility model designs the PTL into a composite structure with woven nickel mesh on both sides and elastic mesh in the middle. The specific process is as follows:

[0053] 1) According to the depth (0.5 - 1 mm) of the flow channel groove of the bipolar plate of the anion exchange membrane AEM electrolytic cell, select two square woven nickel meshes with a thickness of 0.2 - 0.4 mm each.

[0054] 2) Lay the two nickel meshes flat on the pre-built PTL production table. The two nickel meshes are placed in parallel, and the mesh spacing is 0.5 - 1 mm.

[0055] 3) Thread several elastic nickel meshes in a spring-like shape horizontally from one end of the woven nickel mesh, passing a needle and thread to connect two nickel meshes into an integrated structure. In this way, a three-in-one flexible PTL is obtained. All the elastic nickel meshes in the middle are arranged in parallel. The elastic nickel mesh is an elastic support body, and its middle part is a channel for the regular flow of the electrolyte solution.

[0056] In the present utility model, a long strip-shaped through hole is opened on each of the four sides of the bipolar plate, and it is designed into a structure with single-side liquid inlet and gas production on the corresponding side. Moreover, the liquid inlet and gas outlet channels fill the entire frame, basically achieving the effect that the electrolyte solution fills the entire flow field of the bipolar plate. The specific design process is as follows:

[0057] 1) Both sides of the full-flow bipolar plate are designed as a middle concave structure for filling the flexible support porous transport layer (PTL). The concave area is square, and the depth is slightly less than the thickness of the PTL.

[0058] 2) A whole row of liquid inlet flow channel grooves is longitudinally opened at the bottom of the concave part on each side of the full-flow bipolar plate, so that the liquid inlet and gas outlet are evenly and neatly corresponding. The liquid on the entire surface of the full-flow bipolar plate is relatively dispersed, and the flow resistance is very small, and there will be no dead corner area.

[0059] 3) The through diameters of the liquid inlet and gas outlet of the full-flow bipolar plate are relatively large. The cathode and anode are separately fed with liquid and produce gas separately, without interference. The gases are strictly separated, and the gas purity is well guaranteed.

[0060] The integrated membrane electrode is a membrane electrode for hydrogen production by electrolyzing water. Among them, the diaphragm plays a role in isolating hydrogen and oxygen on both sides and ion transport. The diaphragm directly affects the purity of hydrogen and oxygen gases. The sealing structure between the membrane electrode and the full-flow bipolar plate is crucial for the safe operation and no leakage of the electrolytic cell.

[0061] Therefore, the present utility model adopts the above-mentioned full-flow AEM electrolytic cell with a flexible support structure, which adopts an integrated structure, is convenient to assemble, has a low maintenance cost, is conducive to large-scale batch production, and is easier to industrialize. It solves the problem of dead corners in the flow field caused by liquid inlet and gas outlet through holes in the traditional bipolar plate. It can effectively elastically compensate for the thickness of the integrated membrane electrode. Due to its high elasticity characteristics, the requirements for the processing accuracy of the bipolar plate and the structural dimensions of the electrode are greatly reduced. It improves the flow field distribution of the solution, greatly reduces the liquid flow resistance, the solution is more dispersed inside the PTL, and the flow field is also more regular than the traditional method using a metal stretched mesh.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions of the present invention or make equivalent replacements, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A full-flow AEM electrolyzer with a flexible support structure, characterized in that: It includes a flexible supporting porous transmission layer and an integrated membrane electrode, wherein the flexible supporting porous transmission layer and the integrated membrane electrode are both installed between two full-flow bipolar plates, the outer sides of the full-flow bipolar plates and the integrated membrane electrode are respectively connected to the cathode end pressure plate and the anode end pressure plate through positioning holes, the cathode end pressure plate and the anode end pressure plate are connected through bolt holes, and an end pressure plate inlet and outlet slot box is provided on the back of the cathode end pressure plate.

2. A full-flow AEM electrolyzer with a flexible support structure according to claim 1, characterized in that: The flexible supporting porous transmission layer comprises two woven nickel meshes, an elastic nickel mesh is installed between the two woven nickel meshes, the thickness of each woven nickel mesh is 0.2-0.4 mm, and the distance between the two woven nickel meshes is 0.5-1 mm.

3. A full-flow AEM electrolyzer with a flexible support structure according to claim 1, characterized in that: A recessed structure is provided at the center of both the front and back surfaces of the two full-range bipolar plates, and a cathode liquid outlet and a cathode liquid inlet are provided at the top and bottom of the recessed structure on each side, respectively. The bottom of the cathode liquid outlet and the top of the cathode liquid inlet are provided with longitudinally arranged liquid inlet flow channel grooves correspondingly, and the depth of the liquid inlet flow channel grooves is 0.5-1mm. An anode liquid outlet and an anode liquid inlet are provided on the left and right sides of the recessed structure, respectively.

4. A full-flow AEM electrolyzer with a flexible support structure according to claim 3, characterized in that: The full-flow bipolar plate is a rectangular structure, and its material is carbon steel plated with nickel, and the recessed structure is a square structure.

5. A full-flow AEM electrolyzer with a flexible support structure according to claim 3, characterized in that: The integrated membrane electrode is a five-in-one structure, which is arranged in sequence as a polyetheretherketone sealing frame PEEK, a catalyst diffusion layer GDL, an anion membrane AEM, a catalyst diffusion layer GDL and a polyetheretherketone sealing frame PEEK, and the above structures are bonded and connected by polytetrafluoroethylene glue.

6. A full-flow AEM electrolyzer with a flexible support structure according to claim 5, characterized in that: The sizes of the polyetheretherketone sealing frame PEEK and the anion membrane AEM are the same as the size of the full-range bipolar plate, and the size of the catalyst diffusion layer GDL is the same as the size of the recessed structure.

7. A full-flow AEM electrolyzer with a flexible support structure according to claim 6, characterized in that: The thickness of the polyetheretherketone sealing frame PEEK is equal to the thickness of the recessed structure, and the expression thereof is δ(double-layer PEEK+anion membrane AEM)=δ(double-layer GDL after compression+anion membrane AEM).

8. The full-flow AEM electrolyzer with a flexible support structure according to claim 1, characterized in that: The cathode terminal pressure plate is provided with cathode gas outlets on both upper and lower sides, the cathode terminal pressure plate is provided with anode gas outlets on both left and right sides, and a cathode power transmission plate is installed at the bottom center of the cathode terminal pressure plate.

9. A full-flow AEM electrolyzer with a flexible support structure according to claim 1, characterized in that: An anode power transmission plate is installed at the bottom center of the anode terminal plate.

10. The full-flow AEM electrolyzer with a flexible support structure according to claim 1, characterized in that: The end pressure plate inlet and outlet slot box is made of stainless steel, has a hollow structure inside, and the outlet is a flexible joint connection.

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