PEM electrolytic bath pole plate sealing structure, PEM electrolytic bath and PEM water electrolysis hydrogen production device

Abstract

The utility model relates to a PEM electrolytic bath pole plate sealing structure, a PEM electrolytic bath and a PEM water electrolysis hydrogen production device, and belongs to the technical field of water electrolysis hydrogen production. The utility model provides a sealing structure for a polar plate of a PEM electrolytic bath. The sealing structure comprises the polar plate and a sealing ring, one side of the polar plate is sunken inwards to form a sealed groove; the sealing ring is embedded in the sealing groove; the sealing ring comprises a first filling part and a second filling part; the section of the first filling part is rectangular, the section of the second filling part is trapezoidal, and the first filling part is connected with the second filling part, so that the section of the sealing ring is D-shaped; and the section of the sealing groove is rectangular. According to the sealing structure, the sealing ring of the D-shaped structure is adopted, so that when assembling force is applied, the sealing ring does not roll and distort in the process of filling the sealing groove with the sealing ring, the position is stable, and therefore the sealing structure can effectively solve the problems that the sealing ring is exposed or product gas leaks and the like, and the sealing performance is better.

Description

Technical Field

[0001] The utility model relates to a sealing structure of a PEM electrolyzer plate, a PEM electrolyzer and a PEM water electrolysis hydrogen production device, belonging to the technical field of water electrolysis hydrogen production. Background Art

[0002] Water electrolysis is a method of decomposing water molecules to produce hydrogen and oxygen through an electrochemical process. The process mainly involves passing direct current into an electrolytic cell filled with electrolyte. Water molecules undergo electrochemical reactions on the electrodes, decomposing into hydrogen and oxygen, which are precipitated at the cathode and anode, respectively. Currently, there are three main types of water electrolysis hydrogen production systems, including alkaline water electrolysis hydrogen production systems, proton exchange membrane (PEM) water electrolysis hydrogen production systems, and solid oxide water electrolysis hydrogen production systems. Among them, the PEM water electrolysis hydrogen production system is more efficient than the alkaline water electrolysis hydrogen production system, produces purer hydrogen, and is more mature in technology than the solid oxide water electrolysis hydrogen production system. Therefore, the PEM water electrolysis hydrogen production system is currently the focus of research and development in the field of water electrolysis hydrogen production technology.

[0003] The PEM electrolyzer used in the PEM water electrolysis hydrogen production system is mainly composed of a membrane electrode, a gas diffusion layer and a bipolar plate. Among them, the membrane electrode is composed of a cathode, an anode catalyst layer and a proton exchange membrane. In the PEM water electrolysis hydrogen production system, the sealing performance of the PEM electrolyzer is related to its operational safety and electrochemical performance, and is very critical. At present, the sealing method of the PEM electrolyzer is mainly to use the electrode plate and the membrane electrode to squeeze the sealing ring to form a contact seal. Under this sealing method, after the PEM electrolyzer is operated, under the action of the medium and high pressure products hydrogen and oxygen generated during its operation, the sealing ring in the electrode plate sealing groove has a tendency to move outward, and the sealing performance is relatively poor. To solve this problem, the electrode plate groove and the sealing ring structure are generally designed to increase the friction on the pressure contact surface of the sealing ring to prevent the leakage of medium and high pressure gas.

[0004] However, due to the limited sealing performance of the existing PEM electrolyzer plate sealing structure (the existing PEM electrolyzer plate sealing structure is usually composed of a sealing ring with a rectangular cross-section, a plate with a rectangular cross-section sealing groove, and a sealed chamber composed of a membrane electrode), when the plate flow channel area exceeds 1000 cm 2 Furthermore, when the pressure of hydrogen and oxygen products in the electrolyzer exceeds 3 MPa, the sealing ring is easily exposed, resulting in product gas leakage, which directly affects the safe and stable operation of the PEM electrolyzer. Therefore, it is urgent to design a PEM electrolyzer plate sealing structure with better sealing performance to adapt to larger-scale PEM electrolyzers. Summary of the Invention

[0005] To solve the above problems, the present invention provides a sealing structure for a PEM electrolyzer plate, the sealing structure comprising a plate and a sealing ring; one side of the plate is recessed inward to form a sealing groove; the sealing ring is embedded in the sealing groove; the sealing ring comprises a first filling portion and a second filling portion; the cross-section of the first filling portion is rectangular, the cross-section of the second filling portion is trapezoidal, the first filling portion and the second filling portion are connected, so that the cross-section of the sealing ring is "D"-shaped; the cross-section of the sealing groove is rectangular.

[0006] In one embodiment of the present invention, the sealing structure is a sealed chamber composed of an electrode plate, a sealing ring and a membrane electrode.

[0007] In an embodiment of the present invention, one end of the first filling portion of the sealing ring away from the second filling portion abuts against the bottom of the sealing groove.

[0008] In one embodiment of the present invention, the sealing structure further includes sealant; the first filling portion of the sealing ring is fixed to the bottom of the sealing groove by the sealant.

[0009] In one embodiment of the present invention, the sum of the volumes of the sealing ring and the sealant is the same as the volume of the sealing groove.

[0010] In one embodiment of the present invention, the cross-sectional depth (H1) of the electrode plate is 0.5-15 mm; the cross-sectional depth (H2) of the sealing groove is 0.1-15 mm; and the cross-sectional width (m1) of the sealing groove is 0.5-50 mm.

[0011] In one embodiment of the present invention, the cross-sectional depth (H1) of the electrode plate is 0.5-10 mm; the cross-sectional depth (H2) of the sealing groove is 0.1-10 mm; and the cross-sectional width (m1) of the sealing groove is 0.5-30 mm.

[0012] In one embodiment of the present invention, the rectangular cross-section of the sealing groove is composed of four sides: the groove bottom edge, the groove top edge, the first groove side edge and the second groove side edge; the sealing groove is provided with a first chamfer at the junction of the groove bottom edge and the first groove side edge; the axial diameter (R1) of the first chamfer is 0 to 50 mm; the sealing groove is provided with a second chamfer at the junction of the groove bottom edge and the second groove side edge; the axial diameter (R2) of the second chamfer is 0 to 50 mm.

[0013] In one embodiment of the present invention, the cross-sectional depth (h1) of the sealing ring is 0.5 to 30 mm; the cross-sectional depth (h2) of the first filling portion of the sealing ring is 0.1 to 30 mm; the cross-sectional width (L1) of the sealing ring is 0.2 to 50 mm; the "D"-shaped cross-section of the sealing ring is composed of six edges, namely, the bottom edge of the sealing ring, the top edge of the sealing ring, the side edge of the first sealing ring, the side edge of the second sealing ring, the oblique edge of the first sealing ring and the oblique edge of the second filling portion; the angle (a1) between the oblique edge of the first filling portion and the side edge of the first sealing ring is 5 to 85°; the angle (a1) between the oblique edge of the second filling portion and the side edge of the second sealing ring is 5 to 85°.

[0014] In one embodiment of the present invention, the "D"-shaped cross section of the sealing ring is completely symmetrical.

[0015] In one embodiment of the present invention, the electrode plate is a cathode plate and / or an anode plate of a PEM electrolyzer.

[0016] In one embodiment of the present invention, the material of the sealing ring includes at least one of silicone rubber, fluororubber, EPDM rubber, polytetrafluoroethylene, chloroprene rubber, nitrile rubber, hydrogenated nitrile rubber, double fluororubber or metal rubber.

[0017] The utility model also provides a PEM electrolyzer, which is provided with the above-mentioned sealing structure.

[0018] In one embodiment of the present invention, the sealing structure is provided on the cathode plate or the anode plate of the PEM electrolyzer alone, or the sealing structure is provided on both the cathode plate and the anode plate of the PEM electrolyzer.

[0019] In one embodiment of the present invention, the sealing structures on the cathode plate and the anode plate are symmetrically or asymmetrically arranged.

[0020] The utility model also provides a PEM water electrolysis hydrogen production device, which includes the above-mentioned PEM electrolysis cell.

[0021] The technical solution of this utility model has the following advantages:

[0022] The utility model provides a sealing structure for a PEM electrolyzer plate, the sealing structure comprising a plate and a sealing ring; one side of the plate is recessed inward to form a sealing groove; the sealing ring is embedded in the sealing groove; the sealing ring comprises a first filling portion and a second filling portion; the first filling portion has a rectangular cross-section, the second filling portion has a trapezoidal cross-section, and the first and second filling portions are connected, resulting in a "D"-shaped cross-section of the sealing ring; the sealing groove has a rectangular cross-section. When using this sealing structure to seal a single chamber of a PEM electrolyzer, sealant is first applied to the bottom of the plate sealing groove, the "D"-shaped sealing ring is then placed in the plate sealing groove, and finally, during the assembly process of the PEM electrolyzer, an assembly force is applied to achieve effective sealing of the single chamber of the PEM electrolyzer, while also achieving a matching design process for the PEM electrolyzer. The sealing structure uses a "D"-shaped sealing ring, so that when the assembly force is applied, the sealing ring does not roll or twist during the process of filling the sealing groove, and the position is stable. Therefore, the sealing structure can effectively solve problems such as exposed sealing ring or product gas leakage, and has the advantage of better sealing performance, and is suitable for larger-scale PEM electrolyzers.

[0023] Furthermore, one end of the first filling portion of the sealing ring away from the second filling portion abuts against the bottom of the sealing groove (in this case, the second filling portion of the sealing ring, i.e., the trapezoidal cross-section area, is located at the top of the sealing groove). This sealing structure changes the design of the sealing ring, designs the sealing ring into a "D"-shaped structure, and places the second filling portion of the sealing ring with a trapezoidal cross-section at the top of the electrode plate sealing groove. This allows the sealing ring and the sealing groove to be squeezed by external force when the PEM electrolyzer is impacted by gas. The second filling portion of the sealing ring with a trapezoidal cross-section is not easily squeezed out of the sealing groove after being subjected to force, effectively preventing the sealing ring from squeezing out of the gap and "biting" from occurring, further solving the problems of exposed sealing rings or product gas leakage in PEM electrolyzers, and has great application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 : Schematic diagram of the location of the PEM electrolyzer plate sealing structure. Figure 1 In the figure, area A is the flow field structure area of ​​the bipolar plate.

[0025] Figure 2 : Figure 1 Cross-sectional view of section 1-1.

[0026] Figure 3 : Schematic diagram of the structure of the sealing ring.

[0027] Figure 4 : The process of forming the sealing structure between the PEM electrolyzer plate and the membrane electrode (before compression).

[0028] Figure 5: The process of forming the sealing structure between the PEM electrolyzer plate and the membrane electrode (after compression).

[0029] Figures 1 to 5 In the figure, the electrode plate 1, the sealing ring 2, the sealing groove 3, the first filling part 4, the second filling part 5, and the sealant 6. DETAILED DESCRIPTION

[0030] The following embodiments are provided to further understand the present invention, but are not intended to limit the present invention to the best implementation mode described herein and do not limit the content and scope of protection of the present invention. Any product identical or similar to the present invention that is derived by anyone under the inspiration of the present invention or by combining the features of the present invention with other prior arts shall fall within the scope of protection of the present invention.

[0031] If no specific experimental steps or conditions are specified in the following examples, the experiments were carried out according to the conventional experimental steps or conditions described in the literature in the field. If no manufacturer is specified for the reagents or instruments used, they are all commercially available conventional reagents.

[0032] Example 1: A sealing structure for a PEM electrolyzer plate

[0033] like Figures 1 to 5As shown, this embodiment provides a sealing structure for a PEM electrolyzer plate, the sealing structure comprising a sealed chamber consisting of a plate 1, a sealing ring 2 and a membrane electrode; one side of the plate 1 is recessed inward to form a sealing groove 3; the sealing ring 2 is embedded in the sealing groove 3; the sealing ring 2 comprises a first filling portion 4 and a second filling portion 5; the cross section of the first filling portion 4 is rectangular, the cross section of the second filling portion 5 is trapezoidal, the first filling portion 4 and the second filling portion 5 are connected, so that the cross section of the sealing ring 2 is "D"-shaped; the cross section of the sealing groove 3 is rectangular; one end of the first filling portion 4 of the sealing ring 2 away from the second filling portion 5 abuts against the bottom of the sealing groove 3; the sealing structure further comprises a sealant 6; the first filling portion 4 of the sealing ring 2 is fixed to the bottom of the sealing groove 3 by the sealant 6; the sum of the volumes of the sealing ring 2 and the sealant 6 is the same as the volume of the sealing groove 3; the cross-sectional depth (H1) of the plate is 5 mm; the cross-sectional depth (H2) of the sealing groove is 3 mm; the cross-sectional width (m 1) is 3mm; the rectangular cross-section of the sealing groove is composed of four sides: the groove bottom edge, the groove top edge, the first groove side edge, and the second groove side edge; the sealing groove is provided with a first chamfer at the junction of the groove bottom edge and the first groove side edge; the axial diameter (R1) of the first chamfer is 3mm; the sealing groove is provided with a second chamfer at the junction of the groove bottom edge and the second groove side edge; the axial diameter (R2) of the second chamfer is 3mm; the cross-sectional depth (h1) of the sealing ring is 4mm; the cross-sectional depth (h2) of the first filling portion of the sealing ring is is 3mm; the cross-sectional width (L1) of the sealing ring is 2.4mm; the "D"-shaped cross-section of the sealing ring is completely symmetrical on the left and right, and the "D"-shaped cross-section of the sealing ring is composed of six edges: the bottom edge of the sealing ring, the top edge of the sealing ring, the side edge of the first sealing ring, the side edge of the second sealing ring, the oblique edge of the first sealing ring and the oblique edge of the second filling portion; the angle (a1) between the oblique edge of the first filling portion and the side edge of the first sealing ring is 45°; the angle (a1) between the oblique edge of the second filling portion and the side edge of the second sealing ring is 45°; the material of the sealing ring 2 is silicone rubber.

[0034] When using this sealing structure to seal a single chamber of a PEM electrolyzer, first apply sealant to the bottom of the electrode plate sealing groove, then place the "D"-shaped sealing ring in the electrode plate sealing groove, and finally apply assembly force during the assembly process of the PEM electrolyzer to achieve effective sealing of the single chamber of the PEM electrolyzer and simultaneously realize the matching design process of the PEM electrolyzer.

[0035] The sealing structure changes the design of the sealing ring, designs the sealing ring into a "D"-shaped structure, and places the second filling part of the sealing ring with a trapezoidal cross-section on the top of the plate sealing groove, so that when the assembly force is applied, the sealing ring does not roll or twist during the process of filling the sealing groove, and the position is stable. In addition, when the sealing ring and the sealing groove are subjected to external force impact by gas inside the PEM electrolyzer, the second filling part of the sealing ring with a trapezoidal cross-section is not easily squeezed out of the sealing groove after being squeezed by external force, effectively preventing the sealing ring from squeezing out of the gap and "biting" and other phenomena, and can well solve the problems of exposed sealing ring or gas leakage.

[0036] The sealing structure is set on a 100kW PEM electrolyzer (two sealing structures are set, and the two sealing structures are set on the cathode plate and the anode plate at the same time, and the cathode plate and the anode plate are set symmetrically). Figures 4-5 ) Nitrogen was introduced into both the oxygen and hydrogen outlets of the PEM electrolyzer for a leak test (see GB / T37562-2019 for leak testing). The pressure was first increased to 1.0 MPa and stabilized for 10 minutes. Then, it was increased to 1.5 MPa and stabilized for 10 minutes. Then, it was increased to 3.0 MPa and maintained for 24 hours. The pressure dropped to 2.98 MPa, with a leakage rate of 0.03%, indicating the leak test passed.

[0037] Comparative Example 1: A sealing structure for a PEM electrolyzer plate

[0038] This comparative example provides a sealing structure for a PEM electrolyzer plate, wherein the sealing structure is

[0039] On the basis of Example 1, a sealing ring with a rectangular cross-section and a sealing groove with a rectangular cross-section are used, wherein the cross-sectional depth (H1) of the electrode plate is 5 mm; the cross-sectional depth (H2) of the sealing groove is 3 mm; the cross-sectional width (m1) of the sealing groove is 3 mm; the axial diameter (R1) of the first chamfer is 3 mm; the axial diameter (R2) of the second chamfer is 3 mm; the cross-sectional depth (h1) of the sealing ring is 3.5 mm; the cross-sectional width (L1) of the sealing ring is 2.5 mm, the angle (a1) between the oblique side of the first filling portion and the side edge of the first sealing ring is 0°, and the angle (a1) between the oblique side of the second filling portion and the side edge of the second sealing ring is 0°.

[0040] The sealing structure is set on a 100kW PEM electrolyzer (two sealing structures are set, and the two sealing structures are set on the cathode plate and the anode plate at the same time, and the cathode plate and the anode plate are set symmetrically). After the bipolar plates are sealed and pressed, nitrogen is introduced into the oxygen side outlet and the hydrogen side outlet of the PEM electrolyzer at the same time, and an air tightness test is performed on it (for air tightness test, see GB / T37562-2019). The pressure is first increased to 1.0MPa, stabilized for 10min, then increased to 1.5MPa, stabilized for 10min, and then increased to 2.0MPa. The sealing ring of the third chamber leaks and the air tightness test fails.

[0041] Example 2: A PEM electrolyzer

[0042] This embodiment provides a PEM electrolyzer, which is provided with the sealing structure of embodiment 1; the sealing structure is provided on both the cathode plate and the anode plate of the PEM electrolyzer; the sealing structures on the cathode plate and the anode plate are symmetrically arranged.

[0043] Example 3: A PEM water electrolysis hydrogen production device

[0044] This embodiment provides a PEM water electrolysis hydrogen production device, which includes the PEM electrolyzer of Example 2.

[0045] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A sealing structure for a PEM electrolyzer plate, characterized in that: The sealing structure includes an electrode plate and a sealing ring; one side of the electrode plate is recessed inward to form a sealing groove; the sealing ring is embedded in the sealing groove; the sealing ring includes a first filling portion and a second filling portion; the cross-section of the first filling portion is rectangular, and the cross-section of the second filling portion is trapezoidal, and the first filling portion and the second filling portion are connected, so that the cross-section of the sealing ring is "D"-shaped; the cross-section of the sealing groove is rectangular.

2. The sealing structure according to claim 1, wherein: The sealing structure is a sealed chamber composed of an electrode plate, a sealing ring and a membrane electrode.

3. The sealing structure according to claim 1, wherein: One end of the first filling portion of the sealing ring away from the second filling portion abuts against the bottom of the sealing groove.

4. The sealing structure according to any one of claims 1 to 3, wherein: The sealing structure further comprises a sealant; the first filling portion of the sealing ring is fixed to the bottom of the sealing groove by the sealant.

5. The sealing structure according to claim 4, wherein: The sum of the volumes of the sealing ring and the sealant is the same as the volume of the sealing groove.

6. The sealing structure according to claim 1, wherein: The cross-sectional depth of the electrode plate is 0.5 to 15 mm; the cross-sectional depth of the sealing groove is 0.1 to 15 mm; and the cross-sectional width of the sealing groove is 0.5 to 50 mm.

7. The sealing structure according to claim 1, wherein: The rectangular cross-section of the sealing groove is composed of four sides: the groove bottom edge, the groove top edge, the first groove side edge and the second groove side edge; the sealing groove is provided with a first chamfer at the junction of the groove bottom edge and the first groove side edge; the axial diameter of the first chamfer is 0 to 50 mm; the sealing groove is provided with a second chamfer at the junction of the groove bottom edge and the second groove side edge; the axial diameter of the second chamfer is 0 to 50 mm.

8. The sealing structure according to claim 1, wherein: The cross-sectional depth of the sealing ring is 0.5 to 30 mm; the cross-sectional depth of the first filling part of the sealing ring is 0.1 to 30 mm; the cross-sectional width of the sealing ring is 0.2 to 50 mm; the "D"-shaped cross-section of the sealing ring is composed of six edges: the bottom edge of the sealing ring, the top edge of the sealing ring, the side edge of the first sealing ring, the side edge of the second sealing ring, the oblique edge of the first sealing ring and the oblique edge of the second filling part; the angle between the oblique edge of the first filling part and the side edge of the first sealing ring is 5 to 85°; the angle between the oblique edge of the second filling part and the side edge of the second sealing ring is 5 to 85°.

9. A PEM electrolyzer, characterized in that: The PEM electrolyzer is provided with the sealing structure according to any one of claims 1 to 8.

10. A PEM water electrolysis hydrogen production device, characterized in that: The PEM water electrolysis hydrogen production device includes the PEM electrolyzer according to claim 9.

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