Bipolar plate for gas electrolysis device and gas electrolysis device
By introducing a porous cathode plate into the bipolar plate design of the carbon dioxide electrolysis unit, the problems of wetting and drainage were solved, achieving wet sealing and water permeability of the cathode channel, avoiding gas mixing, and reducing costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-11
- Publication Date
- 2026-03-10
AI Technical Summary
Existing carbon dioxide electrolysis devices, while avoiding water intrusion, have difficulty effectively wetting the cathode channel and draining water, resulting in the mixing of reaction gases with gases in the water channel.
Design a bipolar plate in which the water channel formed between the cathode plate and the anode plate is separated from the cathode channel by a porous structure, allowing liquid water to slowly pass through, realizing water exchange, wetting the cathode channel and draining water when it is saturated.
A wet seal was achieved in the cathode channel, preventing the reaction gas from mixing with the gas in the water channel, reducing costs and meeting the water permeability requirements.
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Figure CN223983735U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to a bipolar plate for a gas electrolysis device and to a gas electrolysis device. The present application particularly relates to the field of carbon dioxide electrolysis. BACKGROUND
[0002] Carbon dioxide electrolysis devices are used for the electrolysis of carbon dioxide into products such as formic acid, methanol or ethylene. Carbon dioxide electrolysis devices generally have bipolar plates and membrane electrode assemblies for the electrolysis. The bipolar plates form flow channels for the flow of cooling water, reactants, reaction products therein. The cathode plate and the anode plate of the bipolar plate are each formed by a solid plate and thereby effectively separate the media in the different flow channels from each other. For carbon dioxide electrolysis devices, in order to ensure the humidity of the membrane electrode, in particular the proton exchange membrane, while avoiding water intrusion, a separate humidifier and a water drainage device need to be provided. The humidifier can be provided, for example, between the carbon dioxide pump and the stack, so as to humidify the carbon dioxide supplied to the stack by the carbon dioxide pump. The water drainage device can be provided in the stack or downstream of the stack, in order to prevent water intrusion. SUMMARY
[0003] It is an object of the present application to provide a bipolar plate for a gas electrolysis device, which allows for a water exchange between a cooling water channel and a cathode channel, in particular in order to humidify dry incoming gas in the cathode channel by water in the water channel and to drain water-rich exhaust gas of the cathode channel by the water channel.
[0004] According to a first aspect of the present application, a bipolar plate for a gas electrolysis device is provided, characterized in that the bipolar plate comprises:
[0005] an anode plate;
[0006] a cathode plate;
[0007] a water channel formed between the anode plate and the cathode plate;
[0008] wherein a cathode channel adapted for the flow of a reaction gas is formed on a side of the cathode plate facing away from the anode plate, and wherein a separation portion of the cathode plate separating the cathode channel and the water channel from each other at least partially has a porous structure adapted for the permeation of water therethrough.
[0009] The separation portion is in particular to be understood as the portion of the cathode plate directly separating the cathode channel and the water channel from each other. The separation portion in particular corresponds to the area of the cathode channel and the water channel which overlap in projection. The "permeation through" is in particular to be understood as the porous structure allowing the passage of liquid water, but forming a significant resistance to the passage of liquid water, such that liquid water can only slowly permeate through the porous structure.
[0010] According to an optional embodiment of this application, the porous structure has a pore size of less than 4.2 micrometers.
[0011] According to an optional embodiment of this application, the gas electrolysis device is a carbon dioxide electrolysis device.
[0012] According to an optional embodiment of this application, the thickness of the spacer portion is less than 1 mm.
[0013] According to an alternative embodiment of this application, the cathode plate is configured to have an integral porous structure.
[0014] According to an alternative embodiment of this application, the cathode plate is configured to have a porous structure only in the spaced-out portion.
[0015] According to an optional embodiment of this application, the partition portion has a porous structure overall; or, the partition portion has a porous structure only in the region corresponding to the inlet region and / or outlet region of the cathode channel.
[0016] According to an optional embodiment of this application, the porous structure includes an inlet segment corresponding to the inlet region of the cathode channel, an outlet segment corresponding to the outlet region of the cathode channel, and an intermediate segment between the inlet segment and the outlet segment, wherein the inlet segment and / or the outlet segment is thinner than the intermediate segment; and / or, the pore size in the inlet segment and / or the outlet segment is larger than the pore size in the intermediate segment; and / or, the pore density in the inlet segment and / or the outlet segment is greater than the pore density in the intermediate segment; and / or, the inlet segment and / or the outlet segment is provided with a hydrophilic coating.
[0017] Here, "thinner" refers specifically to the average thickness, and the comparison of apertures refers specifically to the average aperture.
[0018] According to a second aspect of this application, a gas electrolysis apparatus is provided, characterized in that the gas electrolysis apparatus includes an electrode stack, the electrode stack including a membrane electrode assembly and the aforementioned bipolar plate for the gas electrolysis apparatus.
[0019] According to an optional embodiment of this application, the gas electrolysis apparatus includes a gas pump for supplying reactant gases to the stack and / or a water pump for supplying water to the stack.
[0020] At least in some embodiments, the positive effects of this application are as follows: water exchange is possible between the water channel and the cathode channel, allowing the dry reaction gas in the cathode channel to be wetted by water entering the cathode channel from the water channel through the porous structure of the cathode plate, and when the water in the cathode channel is saturated, it can enter the water channel through the porous structure and be discharged; since water can enter the porous structure, a wet seal is formed, thereby especially avoiding the mixing of reaction gas in the cathode channel and gas in the water channel; the permeability of the separated parts can be specifically adapted to meet the permeability requirements while reducing costs. Attached Figure Description
[0021] The principles, features, and advantages of this application will be better understood below with reference to the accompanying drawings. The drawings include:
[0022] Figure 1 An example of a bipolar plate for a gas electrolysis apparatus according to this application is illustrated schematically.
[0023] Figure 2 A partial area of a second example of a cathode plate is schematically shown in a cross-sectional view.
[0024] Figure 3 A partial area of a third example of a cathode plate is schematically shown in a cross-sectional view.
[0025] Figure 4 A fourth example of a cathode plate is illustrated schematically.
[0026] Figure 5 The fifth example of a cathode plate is illustrated schematically.
[0027] Figure 6 The illustration shows a partial example of the fuel cell stack of the gas electrolysis apparatus of this application.
[0028] Figure 7 An example of the gas electrolysis apparatus of this application is shown. Detailed Implementation
[0029] To make the technical problems to be solved, the technical solutions, and the beneficial technical effects of this application clearer, the application will be further described in detail below with reference to the accompanying drawings and several exemplary embodiments. It should be understood that the specific embodiments described herein are only for explaining this application and are not intended to limit the scope of protection of this application.
[0030] Figure 1 An example of a bipolar plate for a gas electrolysis apparatus according to this application is illustrated schematically. The gas electrolysis apparatus is particularly a carbon dioxide electrolysis apparatus for electrolyzing carbon dioxide, but it can also be an electrolysis apparatus for electrolyzing other gases.
[0031] like Figure 1 As shown, the bipolar plate includes:
[0032] Anode plate 1;
[0033] Cathode plate 2;
[0034] A water channel 3 is formed between the anode plate 1 and the cathode plate 2;
[0035] In this process, a cathode channel 40 is formed on the side of the cathode plate 2 opposite to the anode plate 1, which is suitable for the flow of the reaction gas 9. The partition portion 20 of the cathode plate 2 that separates the cathode channel 40 from the water channel 3 has at least partially a porous structure 21 suitable for water to permeate through.
[0036] The porous structure 21 enables water exchange between the water channel 3 and the cathode channel 40, allowing the dry reaction gas 9 in the cathode channel 40 to be wetted by water entering the cathode channel 40 from the water channel 3 via the porous structure 21 of the cathode plate 2, and allowing the water in the cathode channel 40 to be discharged into the water channel 3 via the porous structure 21 when the water in the cathode channel 40 is saturated. Since water can enter the porous structure 21, a wet seal is formed, thereby preventing the mixing of the reaction gas 9 in the cathode channel 40 with the gas in the water channel 3.
[0037] The water channel 3 is specifically used as a channel for the flow of cooling water 80. Furthermore, as... Figure 1 As shown, exemplarily, reactive water 81 also flows in the anode channel 41 as an anode reactant, while the anode product is, for example, oxygen. Figure 1 In the example shown, cooling water 80 in water channel 3, reaction water 81 in anode channel 41, and reaction gas 9 in cathode channel 40 flow from left to right. This flow direction is indicated by an arrow.
[0038] According to an exemplary embodiment of this application, the porous structure 21 has a pore size of 4.2 micrometers or less. This pore size allows water to permeate into the pores of the porous structure 21, thereby effectively preventing gases, particularly the reactive gas 9 and oxygen, from passing through the porous structure 21.
[0039] "Aperture" should be understood as the diameter of the hole.
[0040] Here, the pressure in water channel 3 is generally 1 bar, while the pressure of the reactant gas 9 in cathode channel 40 is generally 1.5 bar at the inlet. Taking into account the consumption of carbon dioxide, the pressure difference between cathode channel 40 and water channel 3 can be considered to be less than or equal to 0.5 bar.
[0041] According to the following formula
[0042]
[0043] It can be calculated that when the pore size is below 4.2 micrometers, gas cannot pass through the porous structure 21 of the cathode plate 2. Here, γ is the surface tension of water, θ is the contact angle, and r is the pore radius.
[0044] Obviously, if the pressure of the reactive gas 9 in the cathode channel 40 is different, other suitable values for the aperture can also be selected.
[0045] According to an exemplary embodiment of this application, the thickness of the spacer portion 20 is less than 1 mm. Choosing such a thickness particularly improves the permeability of the porous structure 21 of the spacer portion 20 of the cathode plate 2.
[0046] With a pore size of 4.2 micrometers, a spacing of 20 with a thickness of 1 millimeter, and a water permeability of 1*10, -15 m 2 Under these conditions, the calculated water flux through the porous structure 21 is 6.94 mol / m³. 2 / s, while the evaporation flux is 1.42 mol / m 2 / s. Thus, the porous structure 21 of the cathode plate 2 can fully meet the requirements for water permeability, especially the requirements for wetting the reaction gas 9.
[0047] According to an exemplary embodiment of this application, see Figure 1 The cathode plate 2 is constructed integrally with a porous structure 21. Here, the cathode plate 2 is made directly from a porous material, for example.
[0048] Figure 2 A partial area of a second example of cathode plate 2 is schematically shown in cross-sectional view. Figure 2 It is a cross-section perpendicular to the flow direction. In Figure 2 For simplicity, only one water channel 3 and one cathode channel 40 are shown as an example. However, those skilled in the art will recognize that the cathode plate 2 may have multiple water channels 3 and multiple cathode channels 40 arranged side by side.
[0049] According to an exemplary embodiment of this application, such as Figure 2 As shown, the cathode plate 2 is configured to have a porous structure 21 only in the spacer portion 20. Here, the cathode plate 2 is made of a non-porous material by locally processing the porous structure 21. Here, by way of example, the spacer portion 20 has a porous structure 21 throughout.
[0050] exist Figure 2In the cathode plate 2, water outlet channels 3 and cathode channels 40 are respectively machined. They are separated from each other by a partition 20. The partition 20 extends specifically perpendicular to the stacking direction of the cathode plate 2 and the anode plate 1. Figure 2 The middle extends in the left-right direction. The stacking direction here is, for example, the up-down direction.
[0051] Figure 3 A partial area of a third example of cathode plate 2 is schematically shown in cross-sectional view. Figure 3 It is also a cross-section perpendicular to the flow direction. Figure 3 In this configuration, the cathode plate 2 is bent to form water channels 3 and cathode channels 40. These channels are separated from each other by a spacer portion 20. The spacer portion 20 extends specifically parallel to the stacking direction of the cathode plate 2 and the anode plate 1. Figure 3 The middle extends in the vertical direction. Furthermore, with... Figure 2 In different ways, Figure 3 In the middle, the partition portion 20 has a porous structure 21 only partially. Here, by way of example, the partition portion 20 has a porous structure 21 only in the upper part. Alternatively or additionally, it is conceivable that the partition portion 20 has a porous structure 21 only in the region corresponding to the inlet region and / or outlet region of the cathode channel 40.
[0052] and Figure 2 and Figure 3 Similarly, one can conceive of various other forms of existence that separate part 20.
[0053] Figure 4 A fourth example of cathode plate 2 is schematically shown. Here, the flow direction is indicated by arrows. Figure 4 As shown, the porous structure 21 may include an inlet section 22 corresponding to the inlet region of the cathode channel 40, an outlet section 24 corresponding to the outlet region of the cathode channel 40, and an intermediate section 23 between the inlet section 22 and the outlet section 24. The inlet section 22 and / or the outlet section 24 may be thinner than the intermediate section 23. Therefore, compared to the intermediate section 23, the inlet section 22 and / or the outlet section 24 have a particularly stronger water exchange capacity.
[0054] Figure 5 A fifth example of cathode plate 2 is schematically shown. Here, the flow direction is indicated by arrows. Figure 5 As shown, the aperture in the inlet section 22 and / or the outlet section 24 can be larger than the aperture in the intermediate section 23. Figure 5 For clarity, only one aperture is shown in magnification.
[0055] In addition, it is used as a substitute for or attached to Figure 4 and Figure 5In some embodiments, it is also conceivable that the pore density in the inlet section 22 and / or the outlet section 24 is greater than the pore density in the intermediate section 23; and / or that the inlet section 22 and / or the outlet section 24 is provided with a hydrophilic coating.
[0056] In addition, similar to the above-described extended scheme, those skilled in the art can also conceive of other variations in the permeability of the separated portion 20.
[0057] Since the cathode plate 2 has multiple water channels 3 and multiple corresponding cathode channels 40, there are also multiple partitions 20. As an addition to or alternative to the above-described extension, it is conceivable that the permeability of these partitions 20 can also differ from one another. For example, the permeability of the longer partitions 20 of the water channels 3 or cathode channels 40 can be set to be lower, while the permeability of the shorter partitions 20 of the water channels 3 or cathode channels 40 can be set to be higher. Conversely, the permeability of the longer partitions 20 of the water channels 3 or cathode channels 40 can be set to be higher, while the permeability of the shorter partitions 20 of the water channels 3 or cathode channels 40 can be set to be lower.
[0058] Figure 6 The illustration schematically shows a partial example of the fuel cell stack 7 of the gas electrolysis apparatus of this application. Two bipolar plates are shown here as an example. However, the fuel cell stack 7 may also have only one bipolar plate or more bipolar plates. Figure 6 As shown, exemplarily, the fuel cell stack 7 also includes a membrane electrode assembly 5. The membrane electrode assembly 5 includes, for example, an anode 51, a cathode 52, and a proton exchange membrane 50. Here, the membrane electrode assembly 5 is sandwiched between two bipolar plates. Furthermore, the fuel cell stack 7 may also include a cathode plate 2 and an anode plate 1 at both ends along the stacking direction.
[0059] exist Figure 6 In the example shown by two arrows in the up-down direction, on the inlet side, water in the water channel 3 passes through the cathode plate 2 to wet the reaction gas 9 of the cathode 52, while on the outlet side, the product water in the reaction gas 9 of the cathode 52 passes through the cathode plate 2 to the water channel 3 and is discharged when saturated.
[0060] Figure 7 An example of the gas electrolysis apparatus of this application is shown.
[0061] According to an exemplary embodiment of this application, such as Figure 7 As shown, the gas electrolysis device includes a gas pump 60 for supplying the reactive gas 9 to the stack 7 and / or a water pump 61 for supplying water to the stack 7.
[0062] Since the humidification and drainage of the reaction gas 9 have been achieved through the cathode plate 2 with the porous structure 21, it is no longer necessary to install a separate humidifier and drainage device for the reaction gas 9.
[0063] In addition, the gas electrolysis device may also have other components, such as valves, pipelines, controllers, sensors, etc. These are well known to those skilled in the art and will not be described in detail here.
[0064] In the context, the concepts related to “entrance,” “exit,” and “middle” can be divided, for example, into one-third of the total length, or into one-quarter of the total length at the entrance and exit, and one-half at the middle, or into one-fifth of the total length at the entrance and exit, and three-fifths at the middle, or similar divisions.
[0065] The dimensions, quantity, position, shape, and interrelationships of the elements in the accompanying drawings should be understood as examples, not as absolute limitations of this application. Those skilled in the art can also conceive of simple variations in the dimensions, quantity, position, shape, and interrelationships of these elements without departing from the scope of protection of this application.
[0066] Provided that it is permissible in principle, each of the cited features can be considered as an individual feature and can be combined with any other feature in any form without departing from the scope of protection of this application. If it is permissible in principle, even if not explicitly stated, a feature described for one embodiment should be considered as being arbitrarily applicable to other embodiments.
[0067] Although specific embodiments of this application are described in detail herein, they are given for illustrative purposes only and should not be construed as limiting the scope of this application. Various substitutions, modifications, and alterations can be conceived without departing from the spirit and scope of this application.
[0068] List of reference numerals
[0069] 1 Anode plate
[0070] 2 Cathode Plates
[0071] 20 separated parts
[0072] 21 Porous Structure
[0073] 22 entrance section
[0074] 23 Middle Section
[0075] 24 Exit Section
[0076] 3 water channels
[0077] 40 Cathode Channel
[0078] 41 Anode Channel
[0079] 5. Membrane Electrode Assembly
[0080] 50 proton exchange membranes
[0081] 51 anode
[0082] 52 cathode
[0083] 60 gas pump
[0084] 61 water pump
[0085] 7 fuel cell stacks
[0086] 80 Cooling Water
[0087] 81 Reaction Water
[0088] 9 Reaction Gases
Claims
1. A bipolar plate for a gas electrolyser, characterised in that, The bipolar plate comprises: an anode plate (1); a cathode plate (2); a water channel (3) formed between the anode plate (1) and the cathode plate (2); wherein a cathode channel (40) adapted for the flow of a reaction gas (9) is formed on a side of the cathode plate (2) facing away from the anode plate (1), and a partition portion (20) of the cathode plate (2) partitioning the cathode channel (40) and the water channel (3) from each other at least partially has a porous structure (21) adapted for the permeation of water therethrough.
2. The bipolar plate for a gas electrolysis device according to claim 1, characterized by The porous structure (21) has a pore diameter of 4.2 micrometers or less.
3. Bipolar plate for a gas electrolysis device according to claim 1 or 2, characterized in that The gas electrolysis device is a carbon dioxide electrolysis device.
4. The bipolar plate for a gas electrolysis device according to claim 1 or 2, characterized by The partition portion (20) has a thickness of 1 millimeter or less.
5. The bipolar plate for a gas electrolysis device according to claim 1 or 2, characterized by The cathode plate (2) is configured to have the porous structure (21) integrally.
6. The bipolar plate for a gas electrolysis device according to claim 1 or 2, characterized by The cathode plate (2) is configured to have the porous structure (21) only in the partition portion (20).
7. The bipolar plate for a gas electrolysis device according to claim 6, characterized by The partition portion (20) has the porous structure (21) integrally; or the partition portion (20) has the porous structure (21) only in regions corresponding to an inlet region and / or an outlet region of the cathode channel (40).
8. The bipolar plate for a gas electrolysis device according to claim 1 or 2, characterized by The porous structure (21) includes an inlet section (22) corresponding to the inlet region of the cathode channel (40), an outlet section (24) corresponding to the outlet region of the cathode channel (40), and an intermediate section (23) between the inlet section (22) and the outlet section (24), The inlet section (22) and / or the outlet section (24) is thinner than the intermediate section (23); and / or The pore diameter in the inlet section (22) and / or the outlet section (24) is larger than the pore diameter in the intermediate section (23); and / or The pore density in the inlet section (22) and / or the outlet section (24) is larger than the pore density in the intermediate section (23); and / or The inlet section (22) and / or the outlet section (24) is provided with a hydrophilic coating.
9. A gas electrolysis device, characterized by The gas electrolysis device includes a stack (7) including a membrane electrode assembly (5) and a bipolar plate for a gas electrolysis device according to any one of claims 1 to 8.
10. The gas electrolysis device of claim 9, wherein, The gas electrolysis device includes a gas pump (60) for supplying a reaction gas (9) to the stack (7) and / or a water pump (61) for supplying water to the stack (7).