A novel bipolar plate assembly and PEM electrolyzer

Abstract

This utility model application discloses a novel bipolar plate assembly and a PEM electrolyzer, which includes an electrode plate body. An anode-side flow field region is provided in the middle of one side of the electrode plate body, and a cathode-side flow field region is provided in the middle of the other side of the electrode plate body. The anode-side flow field region of the electrode plate body is sequentially connected to an anode mesh and a titanium felt. It contains fewer components, reduces contact resistance, and ensures electrolysis efficiency and performance. At the same time, it has fewer processing steps, effectively reducing costs, and is thinner, meeting the design requirements of lightweighting.

Description

Technical Field

[0001] This utility model relates to the field of electrolytic cells, and in particular to a novel bipolar plate assembly and a PEM electrolytic cell. Background Technology

[0002] PEM electrolyzers are one of many hydrogen production technologies. They use pure water as a reactant and are characterized by high hydrogen purity, simple structure and process, and high safety. They are also more adaptable to rapidly changing renewable energy power inputs, making them highly favored by the industry.

[0003] As a key component of PEM electrolyzers, bipolar plates primarily function to conduct electricity and separate the oxidation and reduction reaction zones. Traditional bipolar plates consist of a plate body, frame, titanium felt, and mesh, with these components integrated to form the bipolar plate structure. For example, Chinese invention patent application CN202411592097.X discloses a bipolar plate assembly for a PEM electrolyzer, where the bipolar plate is a stamped structure. A flow channel region is located in the middle of the bipolar plate, with a first composite diffusion layer on one side of the flow channel region and a second composite diffusion layer on the other side. The first composite diffusion layer includes a porous mesh and titanium felt, and the second composite diffusion layer also includes a porous mesh and titanium felt. However, this type of composite bipolar plate assembly, due to the large number of components, results in increased contact resistance, affecting electrolysis efficiency and performance. Furthermore, it is more complex to manufacture, requiring higher costs, and its thickness increases its volume and weight, failing to meet the design requirements for lightweight construction. Utility Model Content

[0004] The problem solved by this utility model is to provide a novel bipolar plate assembly that contains fewer components, reduces contact resistance, ensures electrolysis efficiency and performance, has fewer processing steps, effectively reduces costs, and is thinner, meeting the design requirements for lightweighting.

[0005] In a first aspect, the present invention provides a novel bipolar plate assembly, characterized in that it includes a plate body, an anode-side flow field region is provided in the middle of one side of the plate body, a cathode-side flow field region is provided in the middle of the other side of the plate body, and the anode-side flow field region of the plate body is sequentially connected to an anode mesh and a titanium felt.

[0006] The cathode side of the electrode body is also connected to a cathode plate mesh.

[0007] The electrode body has a flow channel inlet and a flow channel outlet at both ends.

[0008] The electrode body has sealing grooves on both sides. The sealing grooves include flow field sealing grooves and mouth sealing grooves. The flow field sealing grooves are respectively located on the outer periphery of the flow field area of ​​the electrode body, and the mouth sealing grooves are respectively located on the outer periphery of each flow channel inlet and outlet.

[0009] The electrode body is also provided with a flange that runs through the body. The flange is located at both ends of the anode side flow field region and both ends of the cathode side flow field region of the electrode body.

[0010] The anode-side flow field region of the electrode body is a parallel flow field distributed in the horizontal direction, and the cathode-side flow field region of the electrode body is a parallel flow field distributed in the horizontal direction.

[0011] Secondly, this utility model provides a PEM electrolytic cell, which includes the novel bipolar plate assembly described in the first aspect above.

[0012] It also includes multiple membrane electrodes, with the bipolar plate assembly and the membrane electrodes distributed alternately at intervals. The anode side of the membrane electrode is connected to the anode side of the bipolar plate assembly, and the cathode side of the membrane electrode is connected to the cathode side of the bipolar plate assembly.

[0013] The beneficial effects of the novel bipolar plate assembly and PEM electrolytic cell of this utility model application are:

[0014] In this application, by setting the electrode body, it is combined with the anode plate mesh and titanium felt to form an integrated structure only at the anode side flow field area of ​​the electrode body, while no other components are combined on the cathode side. Therefore, the bipolar plate assembly has fewer components, which reduces contact resistance and ensures electrolysis efficiency and performance. At the same time, there are fewer processing steps, which effectively reduces costs. It is also thinner and lighter, meeting the design requirements of lightweighting.

[0015] In this application, a cathode plate mesh can also be provided on the cathode side of the electrode body. The plate mesh has good mechanical properties, and the mesh holes can break up larger bubbles produced on both sides of the electrode assembly, making it easier for the bubbles to be discharged from the flow channel. At the same time, the anode plate mesh on the anode side can not only protect the titanium felt and membrane electrode, but also ensure that the titanium felt and the anode side flow field area have sufficient contact area, further ensuring electrolysis efficiency and performance. Attached Figure Description

[0016] Figure 1 This is an exploded view of the bipolar plate assembly in Embodiment 1 of this utility model;

[0017] Figure 2 This is a front view of the anode side of the electrode plate body of this utility model;

[0018] Figure 3 This is a front view of the cathode side of the electrode plate body of this utility model;

[0019] Figure 4 This utility model Figure 2 Enlarged view of point A in the middle;

[0020] Figure 5 This is an exploded view of the bipolar plate assembly in Embodiment 2 of this utility model;

[0021] Figure 6 This is an overall view of the bipolar plate assembly in Embodiment 2 of this utility model.

[0022] Explanation of reference numerals in the attached figures

[0023] 1. Electrode body; 11. Anode inlet; 12. Anode outlet; 13. Cathode inlet; 14. Cathode outlet; 15. Flanged opening; 2. Anode mesh; 3. Titanium felt; 4. Anode side flow field zone; 41. Distribution flow field zone; 42. Bending flow field zone; 43. Reaction flow field zone; 44. Converging flow field zone; 5. Cathode side flow field zone; 6. Sealing groove; 61. Flow field zone sealing groove; 62. Opening sealing groove; 7. Bridge flow field zone; 8. Cathode mesh. Detailed Implementation

[0024] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0025] In this specification, identical components are represented by the same reference numerals. It should be noted that the terms "front," "rear," "left," "right," "upper," and "lower" used in the following description refer to directions in the accompanying drawings, while the terms "bottom surface," "top surface," "inner," and "outer" refer to directions towards or away from a specific component, respectively. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this specification, "multiple" means two or more.

[0026] The present application will be further described below with reference to the accompanying drawings and embodiments.

[0027] Example 1, such as Figure 1The diagram shown is an exploded view of a bipolar plate assembly. This embodiment provides a novel bipolar plate assembly, including a plate body 1. An anode-side flow field region is provided in the middle of one side of the plate body 1, and a cathode-side flow field region is provided in the middle of the other side of the plate body 1. The flow field region on the anode side of the plate body 1 is sequentially connected to the anode mesh 2 and the titanium felt 3 to form an integrated structure. This connection method can be a diffusion welding connection method.

[0028] In contrast to existing technologies, most bipolar plate assemblies employ a composite structure consisting of multiple components such as the plate body, frame, titanium felt, and mesh plate. This results in numerous components, leading to higher contact resistance, which negatively impacts electrolysis efficiency and performance. Furthermore, the complex manufacturing process involves numerous steps, increasing costs and resulting in thicker, larger, and heavier components, failing to meet lightweight design requirements. In this embodiment, the bipolar plate assembly's plate body is only connected to the anode mesh and titanium felt on the anode side, forming an integrated composite structure. The use of the anode mesh ensures sufficient contact area between the titanium felt and the anode-side flow field region of the plate body. Its excellent mechanical strength also protects the titanium felt and the membrane electrodes in contact with the bipolar plate assembly in the electrolytic cell structure. The mesh openings of the anode mesh also help break up larger air bubbles generated on the anode side of the plate body, facilitating their removal from the flow channel. Meanwhile, in this embodiment, the cathode side of the electrode body is not combined with other components. This is because it was found in actual use that the hydrogen gas evolved on the cathode side would corrode the components on that side, such as titanium felt. By not setting other components, not only are the number of components reduced, but the contact resistance is also reduced, ensuring electrolysis efficiency and performance. At the same time, the thickness of the integrated bipolar plate assembly after composite is thinner, which meets the design requirements of lightweighting. In addition, there are fewer processing steps and the required cost is reduced. The reliability of this structure has been proven through preliminary prototyping and stacking tests.

[0029] like Figure 2 The diagram shows a front view of the anode side of the bipolar plate assembly's plate body 1. The plate body 1 has flow channel inlets and outlets at both ends, specifically including an anode inlet 11, an anode outlet 12, a cathode inlet 13, and a cathode outlet 14. The anode inlet 11 and anode outlet 12 are positioned opposite each other at one diagonal position relative to the plate body 1, and the cathode inlet 13 and cathode outlet 14 are positioned opposite each other at the other diagonal position relative to the plate body 1. In this application, each flow channel inlet and outlet uses a strip-shaped opening with a rectangular cross-section. The four corners of each flow channel inlet and outlet are rounded to reduce fluid resistance and ensure uniform fluid distribution. Furthermore, the dimensions of the anode inlet and outlet are larger than those of the cathode inlet and outlet. Since most of the pure water needs to enter the anode side for the oxygen evolution reaction, while the cathode side undergoes the hydrogen evolution reaction, making the anode inlet and outlet larger facilitates the entry of more pure water for the oxygen evolution reaction.

[0030] Preferably, the anode side of the electrode body 1 has a horizontally distributed anode-side flow field region 4 in the middle. This anode-side flow field region 4 includes a distribution flow field region 41, a bent flow field region 42, a reaction flow field region 43, another bent flow field region 42, and a confluence flow field region 44 connected in sequence. The distribution flow field region 41 is connected to the anode inlet 11, and the confluence flow field region 44 is connected to the anode outlet 12. The distribution flow field region 41, the reaction flow field region 42, and the confluence flow field region 44 all adopt a horizontally distributed parallel flow field, while the bent flow field region 42 adopts a vertically distributed parallel flow field. Different flow field zones are connected by arc-shaped flow channels. The reaction flow field zone 43 is the main working area for the electrolysis reaction. To ensure uniform distribution of reactants and products and good heat dissipation in the reaction flow field zone 43, the number of flow channel ridges in this zone can be set to be 1 to 5 times that of other flow field zones. Increasing the number of flow channel ridges increases the contact area between the fluid and the flow channel, ensuring sufficient reaction, improving electrolysis efficiency, and guaranteeing good heat dissipation. Figure 3 The figure shows a front view of the cathode side of the electrode body 1. The cathode side of the electrode body 1 has a cathode side flow field region 5 distributed in the horizontal direction in the middle. Specifically, the cathode side flow field region 5 includes a distribution flow field region, a bending flow field region, a reaction flow field region, another bending flow field region, and a confluence flow field region connected in sequence. The distribution of the flow field region is similar to that of the anode side flow field region, and will not be described in detail here.

[0031] Preferably, the anode side and cathode side of the electrode body 1 are respectively provided with sealing grooves 6, and the sealing grooves 6 are provided with matching sealing strips (not shown in the figure). The sealing strips are double-layered sealing strips, which can ensure better sealing effect. The sealing grooves 6 ensure that the bipolar plate assembly can be sealed and connected to the membrane electrode during subsequent stacking. Specifically, the sealing grooves 6 include flow field sealing grooves 61 and orifice sealing grooves 62. The flow field sealing grooves 61 are located on the outer periphery of the flow field area of ​​the electrode body 1, and the orifice sealing grooves 62 are located on the outer periphery of each flow channel inlet and outlet of the electrode body 1. The flow field sealing grooves 61 and orifice sealing grooves 62 enable the flow field area and each flow channel inlet and outlet to have a good sealing effect.

[0032] Preferably, such as Figure 2 The image shown is a front view of the anode side of the electrode body. Figure 4The image shows a partial enlarged view of point A on the anode side of the electrode body 1. The electrode body 1 has a flanged opening 15 penetrating through it. There are four flanged openings 15, located at both ends of the anode-side flow field region and both ends of the cathode-side flow field region of the electrode body 1. The flanged openings 15 are located at the ridge of the flow channel at the end of the flow field region of the electrode body 1. For the anode side of the electrode body 1, the flanged opening 15 located in the anode flow field region corresponds to the interior of the opening sealing groove 62 on the cathode side. For the cathode side of the electrode body 1, the flanged opening 15 located in the cathode flow field region corresponds to the interior of the opening sealing groove 62 on the anode side. A bridging flow field region 7 is also provided between the flanged opening 15 and the flow channel inlet and outlet. This bridging flow field region 7 also adopts a parallel flow field, and its size corresponds to the inlet and outlet of the flow field region. In this operation, for the anode side of the electrode body 1, the sealing groove 61 in the flow field area seals the anode-side flow field area 4. The fluid enters from the anode inlet 11 below, flows downwards along the bridge flow field area 7, then passes through the flanged opening 15 and rises into the anode-side flow field area 4 of the electrode body 1 to undergo the anode-side oxygen evolution reaction. The working principle is similar for the cathode side of the electrode body 1, and will not be elaborated here.

[0033] Preferably, the electrode body 1 can be made of titanium plate or stainless steel plate. The four corners of the electrode body 1 are respectively provided with positioning holes, which are used to assemble and connect with other components.

[0034] Example 2 provides another novel bipolar plate assembly, which differs from the bipolar plate assembly in Example 1 in that the cathode side of the bipolar plate assembly also has a composite plate mesh structure, specifically, as shown in... Figure 5 The image shown is an exploded view of a bipolar plate assembly. Figure 6 This is an overall diagram of the bipolar plate assembly. The anode side of the electrode body 1 is sequentially connected to the anode mesh 2 and titanium felt 3, while the cathode side of the electrode body 1 is also connected to the cathode mesh 8, forming an integrated structure. This integrated structure design greatly simplifies subsequent stacking operations. The electrode body, anode mesh, titanium felt, and cathode mesh are welded together using a high-temperature sintering process. Then, a PVD coating process is used to coat both sides of the bipolar plate assembly. The coating surface is the surface of the anode titanium felt and the cathode mesh, significantly reducing coating costs. Titanium mesh is selected because of its excellent mechanical properties, ensuring greater electrical density and better durability. Furthermore, its mesh size is close to the width of the electrode channel, allowing the mesh to break up larger bubbles generated on both sides of the electrode assembly, facilitating their removal from the channel. Simultaneously, the anode mesh on the anode side not only protects the titanium felt and membrane electrode but also ensures sufficient contact area between the titanium felt 3 and the anode-side flow field region, further guaranteeing electrolysis efficiency and performance.

[0035] Example 3: This example provides a PEM electrolyzer, including the bipolar plate assembly described in Example 1 or Example 2 above. The PEM electrolyzer also includes membrane electrodes (not shown in the figure). Multiple membrane electrodes are distributed alternately with the bipolar plate assembly. The anode side of the membrane electrodes is connected to the anode side of the bipolar plate assembly, and the cathode side of the membrane electrodes is connected to the cathode side of the bipolar plate assembly.

Claims

1. A novel bipolar plate assembly, characterized in that, It includes an electrode body, with an anode-side flow field region in the middle of one side of the electrode body and a cathode-side flow field region in the middle of the other side of the electrode body. The anode-side flow field region of the electrode body is sequentially connected to an anode mesh and a titanium felt.

2. The novel bipolar plate assembly according to claim 1, characterized in that, The cathode side of the electrode body is also connected to a cathode plate mesh.

3. A novel bipolar plate assembly according to claim 1 or 2, characterized in that, The electrode body has a flow channel inlet and a flow channel outlet at both ends.

4. A novel bipolar plate assembly according to claim 3, characterized in that, The electrode body has sealing grooves on both sides. The sealing grooves include flow field sealing grooves and mouth sealing grooves. The flow field sealing grooves are respectively located on the outer periphery of the flow field area of ​​the electrode body, and the mouth sealing grooves are respectively located on the outer periphery of each flow channel inlet and outlet.

5. A novel bipolar plate assembly according to claim 4, characterized in that, The electrode body is also provided with a flange that runs through the body. The flange is located at both ends of the anode side flow field region and both ends of the cathode side flow field region of the electrode body.

6. A novel bipolar plate assembly according to claim 5, characterized in that, The anode-side flow field region of the electrode body is a parallel flow field distributed in the horizontal direction, and the cathode-side flow field region of the electrode body is a parallel flow field distributed in the horizontal direction.

7. A PEM electrolytic cell, characterized in that, It includes the novel bipolar plate assembly as described in any one of claims 1-6.

8. A PEM electrolytic cell according to claim 7, characterized in that, It also includes multiple membrane electrodes, with the bipolar plate assembly and the membrane electrodes distributed alternately at intervals. The anode side of the membrane electrode is connected to the anode side of the bipolar plate assembly, and the cathode side of the membrane electrode is connected to the cathode side of the bipolar plate assembly.

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