Integrated runner bipolar plate structure for closed air-cooled fuel cell
By designing a double-sided asymmetric flow channel structure with serpentine reaction channels and parallel heat dissipation channels on a single conductive substrate, the interfacial thermal resistance and sealing reliability of bipolar plate structures are solved, achieving efficient heat dissipation and low-cost manufacturing of fuel cells, and improving the power density and processing efficiency of the stack.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-31
- Publication Date
- 2026-03-27
AI Technical Summary
In existing technologies, bipolar plate structures, while realizing reaction channels and cooling channels, suffer from problems such as high interfacial thermal resistance, poor sealing reliability, complex processes, high costs, and limited heat dissipation performance, which restrict the high power density and low-cost manufacturing of fuel cells.
The design employs a single-board, double-sided asymmetric flow channel, including a serpentine reaction flow channel and a parallel heat dissipation flow channel. The flow channels are processed on both sides of a single conductive substrate and assembled in a complementary manner to form a cooling air channel, thereby achieving efficient distribution of reaction gases and maximizing heat dissipation capacity.
It achieves a high degree of integration of reaction and cooling functions, reduces interfacial thermal resistance and sealing complexity, improves the volumetric and mass power density of the fuel cell stack, simplifies the manufacturing process, reduces costs, and ensures efficient heat dissipation and structural stability.
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Figure CN121748429A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of fuel cell technology, specifically relating to an integrated flow channel bipolar plate structure for a closed-loop air-cooled fuel cell. Background Technology
[0002] Closed-loop air-cooled fuel cells have attracted widespread attention due to their simple structure, compact system, and suitability for mobile power sources and small power systems. As one of the core components of a fuel cell, the bipolar plate performs multiple functions, including distributing reactant gases, collecting current, conducting heat, and constructing cooling air ducts.
[0003] In existing technologies, the following solutions are typically used to simultaneously realize reaction channels and cooling channels:
[0004] 1. Composite plate stacking scheme: Multiple thin plates are processed separately for reaction channels and cooling channels and then stacked together. This has problems such as high interface thermal resistance, poor sealing reliability and complex process.
[0005] 2. Complex processing solutions for thick plates: Processing complex flow channels inside thick plates is difficult and costly, and the heat conduction path is not optimal.
[0006] 3. Functional simplification solution: Sacrificing heat dissipation performance leads to excessive temperature rise during high-power operation, limiting the improvement of system power density.
[0007] Therefore, how to achieve high integration, lightweight design, and low-cost manufacturing of bipolar plate structures while ensuring performance has become a pressing technical problem to be solved in this field. Summary of the Invention
[0008] This invention provides an integrated flow channel bipolar plate structure and its preparation method, aiming to achieve synergistic optimization of efficient distribution of reactant gas, effective discharge of liquid water and maximization of heat dissipation capacity through a single-plate double-sided asymmetric flow channel design.
[0009] To achieve the above objectives, the present invention provides the following technical solution: an integrated flow channel bipolar plate structure for a closed-loop air-cooled fuel cell, comprising a single conductive substrate with a thickness of 1.1 mm, including:
[0010] The first surface is provided with a serpentine reaction channel with a groove depth of 0.25-0.35mm, a groove width of 1.0-1.4mm, and a ridge width of 1.0-1.2mm;
[0011] The second side is provided with parallel heat dissipation channels, with a channel depth of 0.45-0.55mm, a channel width of 1.8-2.2mm, and a ridge width of 0.9-1.1mm;
[0012] The two bipolar plates are assembled with their reaction surfaces facing each other, with a membrane electrode sandwiched in between. The heat dissipation channel of one plate and the solid area on the back of the reaction surface of the other plate together form a cooling air channel.
[0013] Preferably, the serpentine reaction channel has a groove depth of 0.3 mm, a groove width of 1.2 mm, and a ridge width of 1.1 mm.
[0014] Preferably, the parallel heat dissipation channel has a groove depth of 0.5 mm, a groove width of 2.0 mm, and a ridge width of 1.0 mm.
[0015] Preferably, the reaction channel and the heat dissipation channel are arranged perpendicular to each other or at an angle.
[0016] Preferably, the total depth of the cooling air duct is approximately 1 mm.
[0017] This invention also provides a method for fabricating an integrated flow channel bipolar plate structure for a closed-loop air-cooled fuel cell, comprising the following steps:
[0018] Step 1: Substrate preparation: Select a conductive substrate with a uniform thickness of 1.1mm.
[0019] Step 2, First Surface Processing: Process a serpentine reaction flow channel on the first surface of the sheet material;
[0020] Step 3, Second Surface Processing: Flip the board over and, using the ridge surface of the first side as a reference, process parallel heat dissipation channels on the second side;
[0021] Step 4: Auxiliary structure processing: Processing the gas inlet and outlet distribution chambers and sealing grooves;
[0022] Step 5: Cleaning and sealing.
[0023] Step 6: Assembly and curing: Stack the membrane electrode with the membrane electrode to form a stack.
[0024] Preferably, the machining process employs precision milling.
[0025] Preferably, the processing order of the heat dissipation channel and the reaction channel can be interchanged.
[0026] Compared with the prior art, the present invention provides an integrated flow channel bipolar plate structure for closed-loop air-cooled fuel cells, which has the following advantages:
[0027] 1. This invention achieves integrated reaction and cooling functions through a single-plate double-sided asymmetric flow channel design, eliminates the interface impedance of multi-layer plates, and significantly improves the volumetric and mass power density of the fuel cell stack; the heat dissipation flow channel and the solid back of the reaction surface complement each other to form a complete air channel, combined with the cross-flow design to achieve efficient and uniform heat dissipation and adapt to high-power operation.
[0028] 2. This invention requires only two milling operations, eliminating the need for complex overlapping or deep hole machining. The process is simple, yield is high, and manufacturing cost is low. The reasonable ridge width design ensures structural stability during double-sided machining, preventing deformation and damage.
[0029] 3. The serpentine flow channel of this invention facilitates the distribution of reactive gases and the discharge of liquid water, making it suitable for control strategies such as zero hydrogen purging. The heat dissipation flow channel provides a hardware foundation for system integration with external cooling solutions. Attached Figure Description
[0030] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention, but do not constitute a limitation thereof. In the drawings:
[0031] Figure 1 This is a schematic diagram of the parallel channel flow path proposed in this invention;
[0032] Figure 2 This is a schematic diagram of the serpentine flow channel proposed in this invention;
[0033] Figure 3 A cross-sectional schematic diagram of two bipolar plates assembled into a battery cell and forming a cooling air duct. Detailed Implementation
[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0035] Example 1
[0036] like Figures 1 to 3 As shown, the first aspect of the present invention provides an integrated flow channel bipolar plate structure for a closed-loop air-cooled fuel cell, which is composed of a single piece of highly conductive graphite substrate with a thickness of 1.1 mm.
[0037] The first side (reaction surface) of the bipolar plate is machined with a serpentine reaction channel for the distribution of hydrogen or air and the discharge of reaction products; specifically, the groove depth of the serpentine channel is 0.3 mm, the groove width is 1.2 mm, and the ridge width between the channels is 1.1 mm; the second side (heat dissipation surface) of the bipolar plate is machined with parallel direct current channels for the flow of cooling air; specifically, the groove depth of the parallel heat dissipation channel is 0.5 mm, the groove width is 2.0 mm, and the ridge width between the channels is 1.0 mm.
[0038] In the above embodiments, it should be noted that when assembling two bipolar plates with the same structure, they need to be arranged in a "reaction surface facing each other" manner, with a membrane electrode (MEA) sandwiched in the middle. At this time, the 0.5mm deep cooling channel on the heat dissipation surface of one of the bipolar plates is exactly opposite to and fits against the back solid area (thickness of about 0.8mm) of the reaction surface of the adjacent bipolar plate, together forming a complete cooling air channel with a total depth of about 1.0mm and an approximately rectangular cross-section.
[0039] The technical effects achieved by the above embodiments are as follows: through the single-board double-sided asymmetric flow channel design, all necessary functions are integrated on a standard thickness substrate, achieving the ultimate compactness of the structure; the scheme of complementary air channel construction between boards forms a cooling channel with low flow resistance and reasonable cross-sectional area without additional components, laying a hardware foundation for efficient heat dissipation; the serpentine flow channel on the reaction surface ensures the uniformity of the distribution of reaction gas and facilitates drainage, while the reasonable ridge width (1.1mm) ensures sufficient support on the front when processing the 0.5mm deep groove on the back side, resulting in good structural strength and reliability.
[0040] Example 2
[0041] like Figures 1 to 3 As shown, an integrated flow channel bipolar plate structure for a closed-loop air-cooled fuel cell includes all the technical features of Example 1.
[0042] In addition, a key aspect of this embodiment is the optimized design of the flow channel orientation; the overall extension direction of the serpentine reaction flow channel on the first surface and the overall extension direction of the parallel heat dissipation flow channel on the second surface are set to be perpendicular to each other; or, depending on the heat distribution simulation results of the specific fuel cell stack, the two can also be arranged at a specific acute angle (e.g., between 45° and 90°).
[0043] The technical effects achieved by the above embodiments are as follows: the reaction airflow and the cooling airflow are in a cross (vertical or angled) flow pattern, which greatly enhances the heat exchange efficiency; the cooling air can more evenly and effectively remove the heat generated in the reaction zone, avoid the formation of local hot spots, and achieve a uniform temperature distribution of the entire stack; this solves the bottleneck problem of uneven heat dissipation in traditional air-cooled fuel cells, and is particularly beneficial to the stable and long-term operation of the stack under high power density.
[0044] Example 3
[0045] like Figures 1 to 3 As shown, an integrated flow channel bipolar plate structure for a closed-loop air-cooled fuel cell includes all the contents of Example 1 or Example 2.
[0046] The difference in this embodiment lies in the detailed description and optimization of the preparation method of the integrated flow channel bipolar plate. The method specifically includes the following steps: First, prepare a high-conductivity graphite plate with a uniform thickness of 1.1 mm; second, perform first-side processing: use precision milling on the first side of the plate to process a serpentine reaction flow channel with preset parameters; next, perform second-side processing: flip the plate over and use the flat ridge surface formed after the first-side processing as a high-precision reference positioning surface to process parallel heat dissipation flow channels on the second side, ensuring the dimensional accuracy and relative positional relationship of the double-sided flow channels; then, process the inlet / outlet distribution cavity for the reaction gas and cooling air, as well as the surrounding sealing glue groove, on the plate; after that, thoroughly clean the processed plate and apply special fuel cell sealant to the sealing glue groove; finally, precisely align and stack multiple processed bipolar plates and membrane electrode assemblies (MEAs) in sequence, and cure the sealant by pressurization and heating to form a complete fuel cell stack.
[0047] In the above embodiments, it should be noted that the processing order of the heat dissipation channel and the reaction channel can be changed according to the process equipment and fixture conditions. That is, the heat dissipation channel can be processed first, and then the reaction channel can be processed with the ridge surface of the heat dissipation surface as a reference, which can also achieve the purpose of the present invention.
[0048] The technical effects achieved by the above embodiments are as follows: the preparation method has a simple and clear process route, requiring only two precision cutting processes on a single board, avoiding the complex processes such as welding, bonding, and alignment required for multi-board composites in traditional solutions, and also eliminating the need for expensive deep processing technology for thick plates; this not only significantly reduces the investment in production equipment and manufacturing costs, but also greatly improves production efficiency and product yield; using the ridge of the processed surface as the reference for the reverse processing ensures the accuracy of the relative position of the double-sided flow channels, which is the key to achieving the "complementary" bonding of the air channels between boards.
[0049] The working principle and usage process of this invention: In use, the core component, the bipolar plate 1, is made of a single conductive substrate with a thickness of 1.1 mm; its first side is processed with a serpentine reaction channel 2 for distributing reaction gas and discharging liquid water; its second side is processed with a parallel heat dissipation channel 3 for circulating cooling air.
[0050] The key assembly method is to arrange two identical bipolar plates 1 with their reaction surfaces facing each other, with a membrane electrode 4 sandwiched in the middle; at this time, the groove space of the parallel heat dissipation channel 3 of one plate is adjacent to and encloses the solid area 5 on the back of the reaction surface of the other plate, thus forming a complete cooling air channel 6 with a total depth of about one millimeter.
[0051] In actual operation, hydrogen and air enter their respective serpentine reaction channels 2 and diffuse to the membrane electrode 4 to carry out electrochemical reactions to generate current and heat; at the same time, external cooling air is introduced into the cooling air duct 6 to flow; since the heat dissipation channel 3 and the reaction channel 2 are arranged perpendicularly or at a specific angle in spatial direction, the cross flow mode of cooling air and reaction air is realized, which enhances heat exchange efficiency and can uniformly and efficiently remove reaction heat.
[0052] In addition, the path design of the serpentine reaction channel 2 utilizes pressure difference to promote the effective discharge of generated water and prevent flooding. The entire system eliminates the contact thermal resistance and interface resistance between traditional multi-layer boards through a single-board integrated dual-function structure, and constructs an efficient heat dissipation path through the precise complementarity between the solid area 5 between the boards and the channel groove. Ultimately, while ensuring structural strength, it achieves high power density operation and excellent thermal management performance of the fuel cell stack.
[0053] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. An integrated flow channel bipolar plate structure for a closed-loop air-cooled fuel cell, characterized in that, It is composed of a single conductive substrate with a thickness of 1.1 mm, and includes: The first surface is provided with a serpentine reaction channel with a groove depth of 0.25-0.35mm, a groove width of 1.0-1.4mm, and a ridge width of 1.0-1.2mm; The second side is provided with parallel heat dissipation channels, with a channel depth of 0.45-0.55mm, a channel width of 1.8-2.2mm, and a ridge width of 0.9-1.1mm; The two bipolar plates are assembled with their reaction surfaces facing each other, with a membrane electrode sandwiched in between. The heat dissipation channel of one plate and the solid area on the back of the reaction surface of the other plate together form a cooling air channel.
2. The integrated flow channel bipolar plate structure for a closed-loop air-cooled fuel cell according to claim 1, characterized in that, The serpentine reaction channel has a groove depth of 0.3 mm, a groove width of 1.2 mm, and a ridge width of 1.1 mm.
3. The integrated flow channel bipolar plate structure for a closed-loop air-cooled fuel cell according to claim 1, characterized in that, The parallel heat dissipation channel has a groove depth of 0.5 mm, a groove width of 2.0 mm, and a ridge width of 1.0 mm.
4. The integrated flow channel bipolar plate structure for a closed-loop air-cooled fuel cell according to claim 1, characterized in that, The reaction channel and the heat dissipation channel are arranged perpendicular to each other or at an angle.
5. The integrated flow channel bipolar plate structure for a closed-loop air-cooled fuel cell according to claim 1, characterized in that, The total depth of the cooling air duct is approximately 1 mm.
6. A method for fabricating an integrated flow channel bipolar plate structure for a closed-loop air-cooled fuel cell according to any one of claims 1-5, characterized in that, Includes the following steps: Step 1: Substrate preparation: Select a conductive substrate with a uniform thickness of 1.1mm. Step 2, First Surface Processing: Process a serpentine reaction flow channel on the first surface of the sheet material; Step 3, Second Surface Processing: Flip the board over and, using the ridge surface of the first side as a reference, process parallel heat dissipation channels on the second side; Step 4: Auxiliary structure processing: Processing the gas inlet and outlet distribution chambers and sealing grooves; Step 5: Cleaning and sealing. Step 6: Assembly and curing: Stack the membrane electrode with the membrane electrode to form a stack.
7. The method for fabricating an integrated flow channel bipolar plate structure for a closed-loop air-cooled fuel cell according to claim 6, characterized in that, The machining process employs precision milling.
8. The method for fabricating an integrated flow channel bipolar plate structure for a closed-loop air-cooled fuel cell according to claim 6, characterized in that, The processing order of the heat dissipation channel and the reaction channel can be interchanged.