A hybrid flow channel and membrane electrode structure
By using a hybrid flow channel and membrane electrode structure, the problem of insufficient interface matching between the membrane electrode and the bipolar plate was solved, enabling rapid bubble removal and uniform distribution of reactants, thereby improving the mass transfer efficiency and operational stability of the fuel cell.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SINOPEC HYDROGEN ENERGY MACHINERY (WUHAN) CO LTD
- Filing Date
- 2025-08-26
- Publication Date
- 2026-07-31
AI Technical Summary
In the existing technology, the interface matching degree between the membrane electrode and the bipolar plate is insufficient, which leads to the accumulation of oxygen bubbles on the anode side in the bipolar plate flow channel, increasing the mass transfer resistance and intensifying concentration polarization. Existing optimization methods cannot effectively solve the problem of mismatch between bubble discharge rate and generation rate.
The membrane electrode adopts an interlocking flow channel and membrane electrode structure. By etching multiple parallel and spaced flow channels on the bipolar plate and opening grooves on the PTL surface, the membrane electrode and the bipolar plate are tightly interlocked to form a serpentine flow channel structure, which improves the interface matching degree. The design of ribs and grooves between the flow channels promotes the directional movement and rapid discharge of bubbles.
It significantly improves the bubble discharge rate, reduces pressure drop along the flow path and system energy consumption, reduces the probability of bubble blockage, and improves the mass transfer uniformity and reaction efficiency of reactants.
Smart Images
Figure CN224578360U_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of fuel cell technology. More specifically, this invention relates to an interlocking flow channel and membrane electrode structure. Background Technology
[0002] As a core component of hydrogen production equipment, PEM electrolyzers generally face the technical bottleneck of voltage efficiency degradation under high current density operation. Essentially, the accumulation of oxygen bubbles on the anode side within the bipolar plate channels is a key factor leading to increased mass transfer resistance and intensified concentration polarization. In PEM electrolyzers, the membrane electrode assembly (MEA), as the site of electrochemical reactions, directly influences reaction kinetics due to the bubble nucleation behavior at the three-phase interface of its catalyst layer, while the bipolar plate performs the dual functions of distributing the reaction medium and removing the products.
[0003] Currently, membrane electrodes and bipolar plates are often optimized as independent components, and their performance is regulated through catalyst nanostructure (e.g., Surface modification of the porous layer (PTL) or porous transport layer (PTL) can be used to promote initial bubble detachment or optimize the flow channel geometry to enhance fluid shear force. However, this separate optimization method has problems such as insufficient interface matching between the PTL and the flow channel, and mismatch between the bubble discharge rate in the bipolar flow channel and the bubble generation rate in the catalyst layer. It cannot fundamentally solve the problem of oxygen bubble accumulation on the anode side in the bipolar flow channel. Summary of the Invention
[0004] Another objective of this invention is to provide an interlocking flow channel and membrane electrode structure, which can improve the interface matching between the PTL and the flow channel and increase the bubble discharge rate.
[0005] To achieve these objectives and other advantages according to the present invention, an interlocking flow channel and membrane electrode structure is provided, including a bipolar plate and a membrane electrode interlocked on the bipolar plate. The membrane electrode includes a catalyst layer and a PTL stacked from top to bottom. The bipolar plate is engraved with a plurality of parallel and spaced flow channels. The flow direction of the flow fields of the plurality of flow channels is the same, and a flow channel rib is formed between two adjacent flow channels. The PTL surface has multiple grooves, which are arranged one-to-one with the multiple flow channel ribs. The membrane electrode is fitted with the multiple flow channel ribs on the bipolar plate through the multiple grooves.
[0006] Preferably, any flow channel is provided with a first detour section, a second detour section, and a third detour section, and the flow channel is bent around the first detour section, the second detour section, and the third detour section to form a serpentine flow channel structure.
[0007] Preferably, the flow field inlet of any flow channel is located at one end of the bipolar plate, and the flow field outlet is located on the other side of the bipolar plate and is disposed away from the flow field inlet.
[0008] Preferably, the width of the plurality of flow channels is the same.
[0009] Preferably, the width of the plurality of flow channel ribs decreases sequentially from the flow field inlet to the flow field outlet.
[0010] Preferably, the ratio of the height dimension to the width dimension of any flow channel rib is 0.5:1.
[0011] This utility model has at least the following beneficial effects: 1. In this utility model, the PTL is embedded into the bipolar plate through the groove part. After the PTL is embedded, it forms a tight three-dimensional contact with the bipolar plate, which improves the matching degree of the interface between the PTL and the flow channel, significantly reduces the interface gap, shortens the bubble migration distance, avoids the bubble from being stuck at the interface, and improves the bubble discharge rate. 2. The PTL of this utility model is fitted with the flow channel ribs of the bipolar plate through the groove. The fitting position does not affect the flow channel space and does not hinder the bubble discharge. The multiple parallel and spaced flow channels set on the bipolar plate can reduce the pressure drop along the flow path and the system energy consumption. On the other hand, the multi-flow structure can also reduce the probability of bubble blockage. The flow channel ribs between two adjacent flow channels can form a low-resistance priority path, guide the directional movement of bubbles in the flow channel, and effectively reduce the bubble adhesion energy barrier, thereby further improving the bubble discharge rate.
[0012] Other advantages, objectives and features of this invention will be partly apparent from the following description, and partly understood by those skilled in the art through study and practice of this invention. Attached Figure Description
[0013] Figure 1 This is a top view of the bipolar plate of this utility model. Figure 2 This is a schematic diagram of the bipolar plate bypass section of this utility model; Figure 3 This is a front view structural diagram of the bipolar plate of this utility model; Figure 4 This is a front cross-sectional view of the bipolar plate and membrane electrode of this utility model. Explanation of reference numerals in the instruction manual: 1. Bipolar plate, 2. Flow channel, 3. Flow channel rib, 4. PTL, 5. Groove, 6. First detour section, 7. Second detour section, 8. Third detour section, 9. Flow field inlet, 10. Flow field outlet, 11. Catalyst layer. Detailed Implementation
[0014] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.
[0015] It should be noted that in the description of this utility model, the terms "horizontal", "longitudinal", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.
[0016] like Figure 1-4 As shown, this utility model provides an interlocking flow channel and membrane electrode structure, including a bipolar plate 1 and a membrane electrode interlocked on the bipolar plate 1. The membrane electrode includes a catalyst layer 11 and a PTL4 stacked from top to bottom. A plurality of parallel and spaced flow channels 2 are etched on the bipolar plate 1. The flow direction of the flow field of the plurality of flow channels 2 is the same, and a flow channel rib 3 is formed between two adjacent flow channels 2. The PTL4 surface has multiple grooves 5, which are arranged one-to-one with the multiple flow channel ribs 3. The membrane electrode is fitted with the multiple flow channel ribs 3 on the bipolar plate 1 through the multiple grooves 5.
[0017] The optimization method of treating the membrane electrode and bipolar plate 1 as independent components results in a gap between PTL4 and bipolar plate 1 due to their stacked arrangement. This leads to a long bubble migration distance and easy stagnation at the interface during transport, causing oxygen bubbles on the anode side to accumulate in the flow channel 2 of bipolar plate 1. To improve the bubble removal rate on the anode side, in the above technical solution, such as... Figure 1 , Figure 4As shown, this invention features multiple parallel and spaced flow channels 2 etched on the surface of a bipolar plate 1, with inter-flow channel ribs 3 formed between adjacent flow channels 2. Multiple grooves 5 are correspondingly formed on the lower surface of a PTL4, and these grooves 5 interlock with the inter-flow channel ribs 3 in a three-dimensional engagement manner. The PTL4 is partially embedded into the bipolar plate 1 through the grooves 5, resulting in a tight three-dimensional contact between the PTL4 and the bipolar plate. This improves the interface matching between the PTL4 and the flow channels 2, significantly reduces the interface gap, shortens the bubble migration distance, prevents bubbles from lingering at the interface, and increases the bubble discharge rate. The interlocking of the grooves 5 and the inter-flow channel ribs 3 does not affect the space of the flow channels 2 and does not obstruct bubble discharge. The multiple parallel and spaced flow channels 2 on the bipolar plate 1 can, on the one hand, divert flow to reduce pressure drop along the flow path and system energy consumption; on the other hand, the multi-flow structure can also reduce the probability of bubble blockage. The inter-flow channel ribs 3 between adjacent flow channels 2 can form a low-resistance priority path, guiding the directional movement of bubbles within the flow channels 2 and effectively reducing the bubble adhesion energy barrier, thereby further improving the bubble discharge rate.
[0018] In another technical solution, any flow channel 2 is provided with a first detour section 6, a second detour section 7, and a third detour section 8. The flow channel 2 is bent around the first detour section 6, the second detour section 7, and the third detour section 8 to form a serpentine flow channel 2 structure. The flow field inlet 9 of any flow channel 2 is located at the end of one side of the bipolar plate 1, and the flow field outlet 10 is located on the other side of the bipolar plate 1 and is located away from the flow field inlet 9.
[0019] In this technical solution, such as Figure 2 As shown, the flow channel 2 forms a serpentine flow channel 2 structure through the first detour section 6, the second detour section 7, and the third detour section 8. The flow field inlet 9 is located at the end of one side of the bipolar plate 1, and the flow field outlet 10 is located on the other side of the bipolar plate 1 and is far away from the flow field inlet 9. This arrangement allows the flow channel 2 to maximize the increase of the medium flow path within the limited space on the surface of the bipolar plate 1, increase the medium stagnation time, increase the contact time between the medium and PTL4, and increase the reaction probability. The detour section also generates a secondary flow (Dean vortex), which sweeps the bubbles from the wall of the flow channel 2 towards the center of the flow channel 2, further increasing the bubble discharge rate.
[0020] In another technical solution, the width dimensions of the multiple flow channels 2 are the same.
[0021] In this technical solution, the width of multiple flow channels 2 is the same, which can uniformly distribute the pressure and the medium evenly distributed to the PTL4 area, thereby ensuring the mass transfer uniformity and operational stability of the PEM electrolyzer.
[0022] In another technical solution, the width dimensions of the plurality of flow channel ribs 3 decrease sequentially from the flow field inlet 9 to the flow field outlet 10; the ratio of the height dimension of any flow channel rib 3 to its width dimension is 0.5:1.
[0023] In this technical solution, such as Figure 3 As shown, the width of the multiple inter-channel ribs 3 decreases sequentially by 50% from the flow field inlet 9 to the flow field outlet 10. The rib height-to-width ratio of any inter-channel rib 3 remains constant at 0.5. Multiple tests have verified that the sequentially decreasing width of the inter-channel ribs 3 by 50% can homogenize the distribution of reactants on the PTL4 surface, preventing bubble accumulation caused by intense local reactions. Furthermore, maintaining a constant rib height-to-width ratio of 0.5 can disperse the stress at the inter-channel ribs during the electrolytic cell assembly and clamping process, preventing damage to the flow channel 2 structure and thus ensuring structural rigidity and service life. The gradient-decreasing width design of the inter-channel ribs 3, with a constant rib height-to-width ratio of 0.5, results in a stepped arrangement of multiple inter-channel ribs 3, which can induce secondary turbulence, causing bubbles to detach from active sites, freeing up sites for reactant reactions, thus ensuring more complete reactant reactions and preventing bubble accumulation in local areas that would hinder the reaction.
[0024] Example 1 A hybrid flow channel and membrane electrode structure is obtained by interlocking a bipolar plate 1 and a membrane electrode, as shown below. Figure 1 As shown, the area of bipolar plate 1 is 44.5 cm². 2 Four three-dimensional, multi-parallel gradient serpentine flow channels 2 are sequentially engraved on the bipolar plate 1. Each flow channel 2 has a width of 2 mm. Inter-channel ribs A, B, C, and D are sequentially formed between the four flow channels 2. The widths of the inter-channel ribs A, B, C, and D are 4 mm, 2 mm, 1 mm, and 0.5 mm, respectively. Figure 3 As shown, the rib heights are 2mm, 1mm, 0.5mm, and 0.25mm respectively; Figure 4 As shown, the thickness of PTL4 is reduced at the position of the inter-flow channel rib 3 in the direction from the flow field inlet 9 to the flow field outlet 10 on the surface of PTL4 to form multiple grooves 5 that are adapted to the inter-flow channel rib 3 on the surface of PTL4. PTL4 is then fitted onto the multiple inter-flow channel ribs 3 of the bipolar plate 1 through the multiple grooves 5. The catalyst layer 11 is then pressed onto PTL4 to form an interlocking flow channel and membrane electrode structure.
[0025] Although the embodiments of this utility model have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for this utility model. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, this utility model is not limited to the specific details and the illustrations shown and described herein.
Claims
1. A hybrid flow channel and membrane electrode structure, characterized by, The device includes a bipolar plate and a membrane electrode embedded in the bipolar plate. The membrane electrode includes a catalyst layer and a PTL stacked from top to bottom. The bipolar plate is engraved with a plurality of parallel and spaced flow channels. The flow direction of the flow fields of the plurality of flow channels is the same, and a flow channel rib is formed between two adjacent flow channels. The PTL surface has multiple grooves, which are arranged one-to-one with the multiple flow channel ribs. The membrane electrode is fitted with the multiple flow channel ribs on the bipolar plate through the multiple grooves.
2. The hybrid flow channel and membrane electrode structure of claim 1, wherein, Each flow channel is provided with a first detour section, a second detour section, and a third detour section. The flow channel is bent around the first detour section, the second detour section, and the third detour section to form a serpentine flow channel structure.
3. The hybrid flow channel and membrane electrode structure of claim 1, wherein, The flow field inlet of any flow channel is located at one end of the bipolar plate, and the flow field outlet is located on the other side of the bipolar plate and is located away from the flow field inlet.
4. The hybrid flow channel and membrane electrode structure of claim 1, wherein, The width of all of the flow channels is the same.
5. The hybrid flow channel and membrane electrode structure of claim 1, wherein, The width of the multiple flow channel ribs decreases sequentially from the flow field inlet to the flow field outlet.
6. The intercalation flow channel and membrane electrode structure of claim 5, wherein, The ratio of the height dimension to the width dimension of any flow channel rib is 0.5:1.