Bipolar plate assembly structure of PEM electrolytic cell

Abstract

The invention belongs to the technical field of PEM electrolytic baths, and relates to a bipolar plate assembly structure of a PEM electrolytic bath. A combination part of the runner region (102) and the non-runner region (103) is a combination part runner (109) except the positions of the inlet runner bridge (106) and the outlet runner bridge (108), the diffusion layer (301) is attached to the inner side surface of the bipolar plate (101), the edge of the diffusion layer (103) crosses the combination part runner (109) and is attached to the non-runner region (103), the sealing ring (201) is positioned on the outer ring of the diffusion layer (301), and the sealing ring (201) is simultaneously attached to the non-runner region (103), the inlet runner bridge (106) and the outlet runner bridge (108). The diffusion layer (103) is attached to the non-flow-channel area (103), the inlet flow channel bridge (106) and the outlet flow channel bridge (108) at the same time. The PEM electrolytic cell bipolar plate assembly structure is simple in structure and low in cost, connection, positioning and supporting of all parts can be conveniently and reliably achieved, and the operation performance of a PEM electrolytic cell is effectively improved.

Description

Technical Field

[0001] The invention belongs to the technical field of PEM electrolyzers, and more specifically, relates to a bipolar plate assembly structure of a PEM electrolyzer. Background Art

[0002] New energy sources have developed rapidly. Among them, hydrogen energy is a very promising energy carrier, which has received more and more attention due to its high energy density and renewability. Among several hydrogen production technologies, proton exchange membrane (PEM) electrolyzer hydrogen production technology has attracted much attention in recent years due to its advantages such as high current density, low energy consumption, high hydrogen production pressure, more flexible operation, rapid startup, and better adaptability to the volatility of renewable energy.

[0003] The bipolar plate is the core component of the PEM electrolyzer. During operation, the bipolar plate needs to continuously transport water, hydrogen and oxygen, so it needs to have good electron transmission efficiency, thermal conductivity, excellent mechanical properties and uniformly distributed flow field. During the assembly process of the PEM electrolyzer, the bipolar plate plays the role of a "skeleton" inside, which can evenly transfer the assembly pressure of the end plates on both sides to the inside of the electrolyzer, ensuring full contact between the bipolar plate, diffusion layer and membrane electrode, and ensuring the electrolysis efficiency of the electrolyzer. Therefore, the structure of the bipolar plate and the reasonable assembly of its matching components play a vital role in the stable operation of the PEM electrolyzer.

[0004] The disadvantages of the prior art are: the patent application with publication number CN221141893U discloses an assembly structure of a PEM electrolyzer, in which a stepped sealing groove is provided at one end of the electrode plate, and the depth of the stepped sealing groove gradually decreases along the edge direction close to the electrode plate; a stepped sealing ring adapted to the shape of the stepped sealing groove is installed in the stepped sealing groove. By setting the protrusion, the extrusion effect with the stepped sealing groove is further improved, thereby improving the sealing performance. However, the electrode plate corresponding to the assembly structure needs to be processed into a stepped special-shaped structure, which greatly increases the processing cost of the titanium material; at the same time, the stepped sealing structure has certain precision requirements on the size of each component, otherwise it is difficult to fit accurately. Therefore, for the industry of hydrogen production by electrolysis of water, which has an increasing demand, there is an urgent need for a PEM electrolyzer bipolar plate assembly structure with simple structure, low cost and stable performance.

[0005] However, this technology does not involve the technical problems and technical solutions of the present application. Summary of the invention

[0006] The technical problem to be solved by the present invention is: in view of the shortcomings of the prior art, a PEM electrolyzer bipolar plate assembly structure is provided which has a simple structure, low cost, can conveniently and reliably realize the connection, positioning and support of various components, and effectively improves the operating performance of the PEM electrolyzer.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is:

[0008] The present invention is a PEM electrolyzer bipolar plate assembly structure, including an inner side of the bipolar plate including a flow channel area and a non-flow channel area, a flow channel with a serpentine structure is arranged in the flow channel area, an inlet is arranged at the non-flow channel area position on one side of the flow channel area, the inlet is connected to the inlet flow channel bridge of the flow channel area, an outlet is arranged at the non-flow channel area position on the other side of the flow channel area, the outlet is connected to the outlet flow channel bridge of the flow channel area, the junction between the flow channel area and the non-flow channel area is a junction flow channel except for the positions of the inlet flow channel bridge and the outlet flow channel bridge, a diffusion layer is attached to the inner side of the bipolar plate, the edge of the diffusion layer passes over the junction flow channel and is attached to the non-flow channel area, a sealing ring is located on the outer ring of the diffusion layer, the sealing ring 201 is attached to the non-flow channel area, the inlet flow channel bridge and the outlet flow channel bridge at the same time, and the diffusion layer is attached to the non-flow channel area, the inlet flow channel bridge and the outlet flow channel bridge at the same time.

[0009] The PEM electrolyzer bipolar plate assembly structure also includes an anti-overpressure pad and a membrane electrode. The bipolar plate includes a first bipolar plate and a second bipolar plate. The sealing ring includes a first sealing ring and a second sealing ring. The diffusion layer includes a first diffusion layer and a second diffusion layer.

[0010] One side of the membrane electrode is attached to one side of the first diffusion layer, the other side of the membrane electrode is attached to one side of the second diffusion layer, the other side of the first diffusion layer is attached to the first bipolar plate, and the other side of the second diffusion layer is attached to the second bipolar plate.

[0011] The first sealing ring is located at the outer ring of the first diffusion layer, the second sealing ring is located at the outer ring of the second diffusion layer, the anti-overpressure pad is clamped between the non-flow channel area of ​​the first bipolar plate and the non-flow channel area of ​​the second bipolar plate, and the anti-overpressure pad is located at the edge of the non-flow channel area of ​​the first bipolar plate and the edge of the non-flow channel area of ​​the second bipolar plate.

[0012] The inlet flow channel bridge is provided with a first S-shaped step, and the outlet flow channel bridge is provided with a second S-shaped step.

[0013] The bipolar plate is made of TA1 industrial pure titanium, and the processing method of the bipolar plate is chemical etching or CNC machining; the sealing ring is made of silicone or fluororubber or nitrile rubber or polytetrafluoroethylene material, and the processing method of the sealing ring is laser cutting or mold cutting.

[0014] The diffusion layer is made of TA1 industrial pure titanium, and the diffusion layer is made of titanium fiber felt or titanium mesh or titanium sintered plate or sintered titanium powder; the overpressure pad is made of polyethylene or polytetrafluoroethylene, and the processing methods include but are not limited to: laser cutting, mold cutting, etc.

[0015] The membrane electrode is formed by coating cathode catalyst and anode catalyst on both sides of the proton exchange membrane by ultrasonic spraying or thermal transfer process; the anode catalyst uses iridium (Ir) or ruthenium (Ru) precious metal / oxide and its binary or ternary alloy / mixed oxide, and the cathode catalyst uses platinum carbon (Pt / C) particles.

[0016] The compression rate of the sealing ring to play a sealing role The compression rate of the diffusion layer 301 is set to 10% to 40%; the compression rate of the diffusion layer 301 plays a contact and support role Set to 5% to 30%;

[0017] The thickness S of the anti-overpressure pad is 401 The calculation method is:

[0018]

[0019] Where: S 401 —Thickness of overpressure pad 401 (mm);

[0020] S 201 —Thickness of sealing ring (mm);

[0021] —Compression rate of sealing ring (%);

[0022] S 501 —Membrane electrode thickness (mm);

[0023] S 301 —Diffusion layer thickness (mm);

[0024] —Compression ratio of diffusion layer (%).

[0025] The technical solution of the present invention is adopted, and the working principle and beneficial effects are as follows:

[0026] The PEM electrolyzer bipolar plate assembly structure of the present invention has two bipolar plates, two sealing rings, and two diffusion layers. The bipolar plate is provided with an inlet and an outlet, and the inlet 105 and the outlet are connected to the flow channel respectively. The flow channel structure is designed as a serpentine flow channel, covering the flow channel area, and the flow channel is in contact with the diffusion layer; at the same time, the diffusion layer crosses the flow channel area and reaches the non-flow channel area, and is placed on the non-flow channel area of ​​the bipolar plate, and one side of the diffusion layer is in contact with the flow channel of the bipolar plate, and the other side of the diffusion layer is in contact with the catalyst part of the membrane electrode; the sealing ring is assembled around the outer ring of the diffusion layer, and one side of the sealing ring is in contact with the non-flow channel area of ​​the bipolar plate, and the other side of the sealing ring is in contact with the membrane frame part of the membrane electrode. The sealing ring is used as a gas-liquid sealing component of the entire electrolyzer, and the compression required for sealing is provided by the assembly pressure of the electrolyzer; the inlet flow channel bridge and the outlet flow channel bridge are provided to provide effective mechanical support for the sealing ring. The edge of the diffusion layer is placed on the non-channel area of ​​the bipolar plate located on the outer edge of the flow channel, and the diffusion layer is in contact with the flow channel at the same time; relying on the mechanical strength of the diffusion layer and the bridge-like force-bearing structure, it can effectively provide flat mechanical support for the membrane electrode and ensure the stable operation of the electrolyzer. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The following is a brief description of the contents and symbols in the drawings of this specification:

[0028] Figure 1 It is a schematic diagram of the exploded structure of the bipolar plate assembly structure of the PEM electrolyzer according to the present invention;

[0029] Figure 2 A schematic diagram of a top view of the bipolar plate assembly structure of a PEM electrolyzer according to the present invention;

[0030] Figure 3 It is a partial structural schematic diagram of the bipolar plate assembly structure of the PEM electrolyzer according to the present invention;

[0031] Figure 4 It is a partial structural schematic diagram of the bipolar plate assembly structure of the PEM electrolyzer according to the present invention;

[0032] Figure 5 It is a partial structural schematic diagram of the bipolar plate assembly structure of the PEM electrolyzer according to the present invention;

[0033] Figure 6 It is a partial structural schematic diagram of the bipolar plate assembly structure of the PEM electrolyzer according to the present invention;

[0034] Figure 7 A schematic structural diagram of a bipolar plate of a PEM electrolyzer bipolar plate assembly structure according to the present invention;

[0035] Figure 8A schematic structural diagram of a bipolar plate of a PEM electrolyzer bipolar plate assembly structure according to the present invention;

[0036] Fig. 9 It is a partial structural schematic diagram of the bipolar plate assembly structure of the PEM electrolyzer according to the present invention;

[0037] The marks in the accompanying drawings are respectively: 101, bipolar plate; 102, flow channel area; 103, non-flow channel area; 104, flow channel; 105, inlet; 106, inlet flow channel bridge; 107, outlet; 108, outlet flow channel bridge; 109, joint flow channel; 110. Opening; 111, first bipolar plate; 112, second bipolar plate; 113, first S-shaped step; 114, second S-shaped step; 201, sealing ring; 211, first sealing ring; 212, second sealing ring; 301, diffusion layer; 311, first diffusion layer; 312, second diffusion layer; 401, anti-overpressure pad; 501, membrane electrode. DETAILED DESCRIPTION

[0038] The following is a further detailed description of the specific implementation of the present invention, such as the shape, structure, mutual position and connection relationship between the various components involved, the function and working principle of each part, etc., through the description of the embodiments with reference to the accompanying drawings:

[0039] As attached Figure 1 -Attached Fig. 9As shown, the present invention is a PEM electrolyzer bipolar plate assembly structure, including a bipolar plate 101 inner side including a flow channel area 102 and a non-flow channel area 103, the flow channel area 102 is provided with a serpentine flow channel 104, an inlet 105 is provided at the non-flow channel area 103 on one side of the flow channel area 102, the inlet 105 is connected to an inlet flow channel bridge 106 of the flow channel area 102, an outlet 107 is provided at the non-flow channel area 103 on the other side of the flow channel area 102, the outlet 107 is connected to an outlet flow channel bridge 108 of the flow channel area 103, and the flow channel area 104 is provided with an inlet 105. 2 and the non-flow channel area 103, except for the inlet flow channel bridge 106 and the outlet flow channel bridge 108, the joint part of the diffusion layer 301 is the joint flow channel 109, the diffusion layer 103 is attached to the inner side of the bipolar plate 101, the edge of the diffusion layer 103 crosses the joint flow channel 109 and adheres to the non-flow channel area 103, the sealing ring 201 is located on the outer ring of the diffusion layer 301, the sealing ring 201 is attached to the non-flow channel area 103, the inlet flow channel bridge 106 and the outlet flow channel bridge 108 at the same time, and the diffusion layer 103 is attached to the non-flow channel area 103, the inlet flow channel bridge 106 and the outlet flow channel bridge 108 at the same time. The above structure proposes an improved technical solution to address the deficiencies in the prior art. When the structure is set, two bipolar plates 101 are set, two sealing rings 201 are set, and two diffusion layers 301 are set. The bipolar plate 101 is provided with an inlet 105 and an outlet 107, the inlet 105 and the outlet 107 are respectively connected to the flow channel 104, the flow channel 104 is designed as a serpentine flow channel, covers the flow channel area 102, and the flow channel 104 is in contact with the diffusion layer 301; at the same time, the diffusion layer 301 passes over the flow channel area 102 and reaches the non-flow channel area 103, and is placed on the non-flow channel area 103 of the bipolar plate 101, one side of the diffusion layer 301 is in contact with the flow channel 104 of the bipolar plate 101, and the other side of the diffusion layer 301 is in contact with The catalyst part of the membrane electrode 501 is in contact and fit; the sealing ring 201 is assembled around the outer ring of the diffusion layer 301, one side of the sealing ring 201 is in contact and fit with the non-flow channel area 103 of the bipolar plate 101, and the other side of the sealing ring 201 is in contact and fit with the membrane frame part of the membrane electrode 501. The sealing ring 201 is used as the gas-liquid sealing component of the entire electrolyzer, and the assembly pressure of the electrolyzer provides the compression required for sealing; the inlet flow channel bridge 106 and the outlet flow channel bridge 108 are set to provide effective mechanical support for the sealing ring 201. The edge of the diffusion layer 301 is placed on the non-flow channel area on the outer edge of the flow channel 104 on the bipolar plate 101, and the diffusion layer is in contact and fit with the flow channel at the same time; relying on the mechanical strength of the diffusion layer and the bridge-like force-bearing structure, it can effectively provide a flat mechanical support for the membrane electrode and ensure the stable operation of the electrolyzer. The PEM electrolyzer bipolar plate assembly structure of the present invention has a simple structure and low cost, and can conveniently and reliably realize the connection, positioning and support of various components, thereby effectively improving the operating performance of the PEM electrolyzer.

[0040] In the structure of the present invention, at the inlet and outlet of the flow channel 104, the sealing ring 201 is in contact with and fits with the inlet flow channel bridge 106 and the outlet flow channel bridge 108 respectively, and the sealing ring 201 is in contact with and fits with the membrane frame area of ​​the membrane electrode 501 at the same time. The sealing ring 201 is provided with the compression rate required for sealing by the electrolytic cell assembly pressure. The diffusion layer 301, as a gas-liquid two-phase transmission structure, directly contacts and fits with the flow channel area 102 of the bipolar plate 101 during the high-pressure assembly process. If the diffusion layer 301 is exactly the same size as the flow channel area 102 of the bipolar plate 101, it will be suspended above the flow channel 109 of the joint around the bipolar plate 101, and will be in an overhead state. Under high-pressure assembly conditions, the diffusion layer will be squeezed and bent, or even broken, causing the membrane electrode to be displaced and ruptured at the deformation position of the diffusion layer. The arrangement of the diffusion layer of the present invention effectively protects the diffusion layer.

[0041] The PEM electrolyzer bipolar plate assembly structure further includes an overpressure protection pad 401 and a membrane electrode 501. The bipolar plate 101 includes a first bipolar plate 111 and a second bipolar plate 112. The sealing ring 201 includes a first sealing ring 211 and a second sealing ring 212. The diffusion layer 301 includes a first diffusion layer 311 and a second diffusion layer 312. One side of the membrane electrode 501 is attached to one side of the first diffusion layer 311, and the other side of the membrane electrode 501 is attached to one side of the second diffusion layer 312. The other side of the first diffusion layer 311 is attached to the first bipolar plate 111, and the other side of the second diffusion layer 312 is attached to the second bipolar plate 112. In the above structure, the overpressure protection pad 401 is installed between the first bipolar plate 111 and the second bipolar plate 112, and is located at the edge of the first bipolar plate 111 and the second bipolar plate 112. Its thickness can control the total compression height; the membrane electrode 501 is installed in the middle of the electrolytic cell to participate in the catalytic reaction, the catalyst part is in contact with the diffusion layer, and the membrane frame part is in contact with the sealing ring.

[0042] The first sealing ring 211 is located on the outer ring of the first diffusion layer 311, the second sealing ring 212 is located on the outer ring of the second diffusion layer 312, the overpressure protection pad 401 is sandwiched between the non-flow channel area 103 of the first bipolar plate 111 and the non-flow channel area 103 of the second bipolar plate 112, and the overpressure protection pad 401 is located at the edge of the non-flow channel area 103 of the first bipolar plate 111 and the edge of the non-flow channel area 103 of the second bipolar plate 112. In the above structure, the sealing ring 201 is assembled around the diffusion layer 301, one side surface of the sealing ring 201 is in contact with the non-flow channel area 103 of the first bipolar plate 111, and the primary surface of the sealing ring 201 is in contact with the membrane frame part of the membrane electrode 501. The sealing ring 201 serves as the gas-liquid sealing component of the entire electrolytic cell, and the compression required for sealing is provided by the assembly pressure of the electrolytic cell. The sealing ring can reliably play the role of sealing the outer ring. The first bipolar plate, the second bipolar plate, and the anti-overpressure pad 401 are respectively provided with openings 110 for bolts to pass through, so as to fix the first bipolar plate and the second bipolar plate and form a PEM electrolyzer with reliable performance.

[0043] The first S-shaped step 113 is provided at the inlet flow channel bridge 106, and the second S-shaped step 114 is provided at the outlet flow channel bridge 108. In the above structure, the first S-shaped step is provided at the inlet of the flow channel, and the second S-shaped step is provided at the outlet of the flow channel. Without hindering the transmission of the inlet and outlet fluids, the first S-shaped step provides effective mechanical support for the bottom of the inlet flow channel bridge, and the second S-shaped step provides effective mechanical support for the bottom of the outlet flow channel bridge.

[0044] The bipolar plate 101 is made of TA1 industrial pure titanium, and the processing method of the bipolar plate 101 is chemical etching or CNC machining; the sealing ring 201 is made of silicone or fluororubber or nitrile rubber or polytetrafluoroethylene material, and the processing method of the sealing ring 201 is laser cutting or mold cutting. The diffusion layer 301 is made of TA1 industrial pure titanium, and the diffusion layer is made of titanium fiber felt or titanium mesh or titanium sintered plate or sintered titanium powder material; the overpressure pad 401 is made of polyethylene or polytetrafluoroethylene material, and the processing method includes but is not limited to: laser cutting, mold cutting, etc. The membrane electrode 501 is formed by coating the cathode catalyst and the anode catalyst on both sides of the proton exchange membrane by ultrasonic spraying or thermal transfer process; the anode catalyst uses iridium (Ir) or ruthenium (Ru) precious metal / oxide and its binary or ternary alloy / mixed oxide, and the cathode catalyst uses platinum carbon (Pt / C) particles.

[0045] The compression rate of the sealing ring 201 for sealing is The compression rate of the diffusion layer 301 is set to 10% to 40%; the compression rate of the diffusion layer 301 plays a contact and support role Set to 5% to 30%;

[0046] The thickness S of the anti-overpressure pad 401 is 401 The calculation method is:

[0047]

[0048] Where: S 401 —Thickness of overpressure pad 401 (mm);

[0049] S 201 -Thickness of sealing ring 201 (mm);

[0050] —Compression rate of sealing ring 201 (%);

[0051] S 501 - membrane electrode 501 thickness (mm);

[0052] S 301 —Thickness of diffusion layer 301 (mm);

[0053] -Compression ratio of diffusion layer 301 (%).

[0054] The PEM electrolyzer bipolar plate assembly structure of the present invention is provided with two bipolar plates 101, two sealing rings 201, and two diffusion layers 301. The bipolar plate 101 is provided with an inlet 105 and an outlet 107, which are respectively connected to the flow channel 104. The flow channel 104 is designed as a serpentine flow channel, covering the flow channel area 102. The flow channel 104 is in contact with the diffusion layer 301; at the same time, the diffusion layer 301 passes over the flow channel area 102 and reaches the non-flow channel area 103, and is placed on the non-flow channel area 103 of the bipolar plate 101. One side of the diffusion layer 301 is in contact with the flow channel 104 of the bipolar plate 101, and the other side of the diffusion layer 301 is in contact with the flow channel 104 of the bipolar plate 101. The catalyst part of the membrane electrode 501 is in contact and fit; the sealing ring 201 is assembled around the outer ring of the diffusion layer 301, one side of the sealing ring 201 is in contact and fit with the non-flow channel area 103 of the bipolar plate 101, and the other side of the sealing ring 201 is in contact and fit with the membrane frame part of the membrane electrode 501. The sealing ring 201 is used as the gas-liquid sealing component of the entire electrolyzer, and the assembly pressure of the electrolyzer provides the compression required for sealing; the inlet flow channel bridge 106 and the outlet flow channel bridge 108 are set to provide effective mechanical support for the sealing ring 201. The edge of the diffusion layer 301 is placed on the non-flow channel area on the outer edge of the flow channel 104 on the bipolar plate 101, and the diffusion layer is in contact and fit with the flow channel at the same time; relying on the mechanical strength of the diffusion layer and the bridge-like force-bearing structure, it can effectively provide a flat mechanical support for the membrane electrode, avoid damage to the diffusion layer, and the sealing ring can be reliably sealed to ensure the stable operation of the electrolyzer.

[0055] The present invention is described above by way of example in conjunction with the accompanying drawings. It is obvious that the specific implementation of the present invention is not limited to the above-mentioned method. As long as various improvements are made using the method concept and technical solution of the present invention, or the concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A PEM electrolyzer bipolar plate assembly structure, characterized in that: The bipolar plate (101) comprises a flow channel region (102) and a non-flow channel region (103) on the inner side thereof, the flow channel region (102) is provided with a flow channel (104) of a serpentine structure, an inlet (105) is provided at the position of the non-flow channel region (103) on one side of the flow channel region (102), the inlet (105) is connected to an inlet flow channel bridge (106) of the flow channel region (102), an outlet (107) is provided at the position of the non-flow channel region (103) on the other side of the flow channel region (102), the outlet (107) is connected to an outlet flow channel bridge (108) of the flow channel region (103), the flow channel region (102) and the non-flow channel region (103) are connected to each other. The joint part of the bipolar plate (101) is a joint flow channel (109) except for the positions of the inlet flow channel bridge (106) and the outlet flow channel bridge (108); the diffusion layer (301) is attached to the inner side of the bipolar plate (101); the edge of the diffusion layer (103) crosses the joint flow channel (109) and is attached to the non-flow channel area (103); the sealing ring (201) is located on the outer ring of the diffusion layer (301); the sealing ring (201) is attached to the non-flow channel area (103), the inlet flow channel bridge (106) and the outlet flow channel bridge (108) at the same time; and the diffusion layer (103) is attached to the non-flow channel area (103), the inlet flow channel bridge (106) and the outlet flow channel bridge (108) at the same time.

2. The PEM electrolyzer bipolar plate assembly structure according to claim 1, characterized in that: The PEM electrolyzer bipolar plate assembly structure further comprises an anti-overpressure pad (401) and a membrane electrode (501); the bipolar plate (101) comprises a first bipolar plate (111) and a second bipolar plate (112); the sealing ring (201) comprises a first sealing ring (211) and a second sealing ring (212); and the diffusion layer (301) comprises a first diffusion layer (311) and a second diffusion layer (312).

3. The PEM electrolyzer bipolar plate assembly structure according to claim 1, characterized in that: One side of the membrane electrode (501) is bonded to one side of the first diffusion layer (311), the other side of the membrane electrode (501) is bonded to one side of the second diffusion layer (312), the other side of the first diffusion layer (311) is bonded to the first bipolar plate (111), and the other side of the second diffusion layer (312) is bonded to the second bipolar plate (112).

4. The PEM electrolyzer bipolar plate assembly structure according to claim 1, characterized in that: The first sealing ring (211) is located on the outer ring of the first diffusion layer (311), the second sealing ring (212) is located on the outer ring of the second diffusion layer (312), the overpressure prevention pad (401) is clamped between the non-flow channel area (103) of the first bipolar plate (111) and the non-flow channel area (103) of the second bipolar plate (112), and the overpressure prevention pad (401) is located at the edge of the non-flow channel area (103) of the first bipolar plate (111) and the edge of the non-flow channel area (103) of the second bipolar plate (112).

5. The PEM electrolyzer bipolar plate assembly structure according to claim 1, characterized in that: A first S-shaped step (113) is provided at the inlet flow channel bridge (106), and a second S-shaped step (114) is provided at the outlet flow channel bridge (108).

6. The PEM electrolyzer bipolar plate assembly structure according to claim 1, characterized in that: The bipolar plate (101) is made of TA1 industrial pure titanium, and the processing method of the bipolar plate (101) is chemical etching or CNC machining; the sealing ring (201) is made of silicone or fluororubber or nitrile rubber or polytetrafluoroethylene material, and the processing method of the sealing ring (201) is laser cutting or mold cutting.

7. The PEM electrolyzer bipolar plate assembly structure according to claim 1, characterized in that: The diffusion layer (301) is made of TA1 industrial pure titanium, and the diffusion layer is made of titanium fiber felt or titanium mesh or titanium sintered plate or sintered titanium powder material; the overpressure protection pad (401) is made of polyethylene or polytetrafluoroethylene material, and the processing methods include but are not limited to: laser cutting, mold cutting, etc.

8. The PEM electrolyzer bipolar plate assembly structure according to claim 1, characterized in that: The membrane electrode (501) is formed by coating cathode catalyst and anode catalyst on both sides of a proton exchange membrane by ultrasonic spraying or thermal transfer process; the anode catalyst uses iridium (Ir) or ruthenium (Ru) noble metal / oxide and its binary or ternary alloy / mixed oxide, and the cathode catalyst uses platinum carbon (Pt / C) particles.

9. The PEM electrolyzer bipolar plate assembly structure according to claim 1, characterized in that: The compression rate of the sealing ring (201) for sealing The compression rate of the diffusion layer (301) is set to 10% to 40%; the compression rate of the diffusion layer (301) plays a contact and support role Set to 5% to 30%.

10. The PEM electrolyzer bipolar plate assembly structure according to claim 1, characterized in that: The thickness S of the anti-overpressure pad (401) is 401 The calculation method is: Where: S 401 —Thickness of overpressure protection pad (401) (mm); S 201 -Thickness of sealing ring (201) (mm); —Compression rate of sealing ring (201) (%); S 501 - membrane electrode (501) thickness (mm); S 301 —Thickness of diffusion layer (301) (mm); —Compression ratio of diffusion layer (301) (%).

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