Fuel cell flow channel polar plate, flow channel structure and fuel cell

Abstract

The application relates to a fuel cell flow channel polar plate, which has opposite cooling liquid contact sides and gas contact sides, and comprises a plurality of flow channel grooves, a plurality of flow channel protrusions and a plurality of flow blocking protrusions. The plurality of flow channel grooves are arranged in a first direction and are recessed towards the cooling liquid contact side. Any two adjacent flow channel grooves are provided with a flow channel protrusion, which protrudes towards the gas contact side. The plurality of flow blocking protrusions are arranged in a second direction on the side of the flow channel grooves facing the gas contact side. The flow channel grooves and the flow channel protrusions alternately form gas main channels and support structures, and the flow blocking protrusions are arranged along the flow direction on the bottom surface of the flow channel grooves, so that periodic local disturbances are formed to break the laminar boundary layer, enhance the normal mass transfer and improve the mass transfer efficiency.

Description

Technical Field

[0001] This application relates to the field of battery technology, specifically to a fuel cell flow channel plate, flow channel structure, and fuel cell. Background Technology

[0002] The flow channel structure on the fuel cell plates is a core component determining the stack's performance, lifespan, and operational stability. The flow channels play a crucial role in uniformly delivering the reactant gases (hydrogen and air) to the gas diffusion layer and catalyst layer, while simultaneously removing the water generated during the reaction. Traditional flow channel designs, such as direct-flow or parallel channels, typically consist of alternating ridges and grooves, with gas flowing unidirectionally along the channels. However, this type of structure exhibits serious drawbacks in actual high-current-density operation: due to the dominance of laminar flow, gas flow in the core region of the flow channel and mass exchange near the wall (gas diffusion layer interface) primarily rely on molecular diffusion, resulting in low mass transfer efficiency. Simultaneously, water generated by the electrochemical reaction easily accumulates in the diffusion layer and at the bottom of the flow channel, creating "flooding," which blocks the gas transport channels, leading to a sharp increase in concentration polarization losses and a drastic drop in battery performance. Summary of the Invention

[0003] One of the objectives of this application is to provide a fuel cell flow channel plate, flow channel structure, and fuel cell to solve the technical problems mentioned in the background art.

[0004] To achieve the above objectives, in a first aspect, this application provides a fuel cell flow channel plate having a coolant contact side and a gas contact side, the fuel cell flow channel plate including a plurality of flow channel grooves, a plurality of flow channel protrusions and a plurality of flow blocking protrusions, the plurality of flow channel grooves being arranged along a first direction and the flow channel grooves being recessed toward the coolant contact side, and a flow channel protrusion being provided between any two adjacent flow channel grooves, the flow channel protrusion being protruded toward the gas contact side; Multiple flow-blocking protrusions are arranged along a second direction on the side of the flow channel facing the gas contact side; the second direction is the gas flow direction, and the first direction is perpendicular to the gas flow direction.

[0005] Based on the above technical means, the main gas channel and support structure are formed by alternating flow channel grooves and flow channel protrusions, and flow blocking protrusions are set on the bottom surface of the flow channel along the flow direction to achieve periodic local disturbances to destroy the laminar boundary layer and enhance normal mass transfer, while not changing the main gas flow direction and the pressure drop increases only slightly, thereby improving mass transfer efficiency under the premise of low pressure drop.

[0006] Furthermore, the flow blocking protrusion includes a first flow blocking protrusion and a second flow blocking protrusion. A plurality of the first flow blocking protrusions are arranged along a second direction on the side of the flow channel groove facing the gas contact side, and a plurality of the second flow blocking protrusions are arranged along a second direction on the side of the flow channel protrusion facing the gas contact side.

[0007] Based on the above technical means, flow blocking protrusions are set on both the bottom surface of the flow channel and the top surface of the flow channel protrusion, thereby realizing the disturbance of gas flow on both the upper and lower sides.

[0008] Furthermore, it includes multiple flow channel blocking protrusions, which are arranged in the flow channel groove along the second direction, and one flow channel blocking protrusion is provided between any two adjacent first flow blocking protrusions. The flow channel blocking protrusions protrude toward the side away from the coolant contact side. The two ends of the flow channel blocking protrusion extend into the two flow channel protrusions adjacent to the flow channel groove, respectively.

[0009] According to the above technical means, by alternating the flow channel blocking protrusions that span the entire flow channel and the first flow blocking protrusion, a strong sudden contraction and expansion effect is generated, which significantly enhances gas disturbance and boundary layer destruction; at the same time, the two ends of the flow channel blocking protrusions extend into the flow channel protrusions, forming a transverse connecting channel on the coolant side, constructing a mesh coolant flow path, and simultaneously enhancing gas-side mass transfer and water-side heat exchange.

[0010] Furthermore, the side of the flow channel blocking protrusion away from the coolant contact side is provided with a groove, the groove is recessed towards the coolant contact side, and the projection of the groove along the thickness direction of the fuel cell flow channel plate falls into the flow channel groove.

[0011] According to the above technical means, when gas flows through the blockage protrusion that spans the entire flow channel, the groove provides an additional flow cross section, allowing some gas to pass through from above the groove, thereby avoiding excessive local pressure drop caused by the blockage protrusion completely blocking the flow channel groove.

[0012] Furthermore, it includes multiple grooved bottom plates and multiple raised top plates, the grooved bottom plates and the raised top plates being alternately connected in sequence along a first direction, and each raised top plate being connected to two adjacent grooved bottom plates by a connecting plate; the space enclosed between the grooved bottom plates and the two connected connecting plates forms the flow channel groove; the grooved bottom plates protrude toward the side away from the coolant contact side to form the first flow blocking protrusion, and the raised top plates protrude toward the side away from the coolant contact side to form the second flow blocking protrusion.

[0013] According to the above-mentioned technical means, the third plate and the fifth plate constitute the two side walls of the groove. The cross-sectional shape makes the flow channel blocking protrusion present a profile that is low in the middle and high at both ends on the gas contact side, thereby forming a downward-concave groove structure at the top of the flow channel blocking protrusion so that gas can pass through.

[0014] Furthermore, the side of the first flow blocking protrusion away from the bottom plate of the groove and the side of the second flow blocking protrusion away from the top plate of the protrusion are located on the same plane. The side of the flow channel blocking protrusion away from the coolant contact side is coplanar with the side of the first flow blocking protrusion away from the groove bottom plate.

[0015] According to the above technical means, the top surfaces of the first flow blocking protrusion, the second flow blocking protrusion, and the flow channel blocking protrusion are coplanar, ensuring that the gas diffusion layer is uniformly supported locally after assembly, and avoiding local overpressure or suspension due to height differences.

[0016] Furthermore, along the second direction, the distance between any two adjacent flow-blocking protrusions is a constant. Alternatively, the distance between two adjacent flow-blocking protrusions along the second direction decreases sequentially along that direction by a fixed difference.

[0017] According to the above-mentioned technical means, by reducing the spacing between the flow blocking protrusions downstream, the boundary layer can be disrupted more frequently, and a backflow zone and pressure difference can be generated, thereby enhancing the gas mixing and convection mass transfer efficiency in the downstream region.

[0018] Furthermore, a flow gap is formed between the flow channel protrusion and the opposite gas diffusion layer.

[0019] According to the above-mentioned technical means, under pressure, the gas can directly enter the ridge region through the flow gap between the top surface of the flow channel protrusion and the gas diffusion layer, and then diffuse vertically or convect into the gas diffusion layer. The reactants can reach the surface of the catalyst layer in the ridge region more quickly, and the mass transfer efficiency is improved.

[0020] Furthermore, a first coolant flow channel is formed on the side of the flow channel protrusion facing the coolant contact side, and a second coolant flow channel is formed on the side of the flow channel blocking protrusion facing the coolant contact side. The second coolant flow channel is connected to the two adjacent first coolant flow channels.

[0021] According to the above-mentioned technical means, the coolant is no longer limited to flowing in a single direction, but can flow in both the first and second directions, redistributing the flow rate and temperature, thereby reducing the overall flow resistance and enhancing the heat exchange effect with the plates.

[0022] Furthermore, the flow-blocking protrusion can be any one of a cylinder, rhombus, square, or teardrop shape.

[0023] Based on the above technical means, the optimal geometric configuration can be flexibly selected according to specific mass transfer requirements, pressure drop limitations and processing conditions.

[0024] A second aspect of this application provides a flow channel structure, including the aforementioned fuel cell flow channel plate. The fuel cell flow channel plate is divided into a cathode flow channel plate and an anode flow channel plate. The flow channel structure includes a coolant flow channel and a gas flow channel. The coolant flow channel is formed between the side of the cathode flow channel plate facing the coolant contact side and the side of the anode flow channel plate facing the coolant contact side. The gas flow channel is formed between the side of the cathode flow channel plate facing the gas contact side and the cathode gas diffusion layer. The gas flow is formed between the side of the anode flow channel plate facing the gas contact side and the anode gas diffusion layer.

[0025] A third aspect of this application provides a fuel cell, including the aforementioned flow channel structure, cathode gas diffusion layer, cathode gas catalyst layer proton exchange membrane, anode catalyst layer, and anode gas diffusion layer.

[0026] The beneficial effects of this application are: First, when gas flows through the flow blocking protrusions in the flow channel, the protrusions act as physical obstacles, forcing the gas to flow around them. This creates a stagnation zone in front of the protrusions, acceleration zones on both sides, and a low-pressure backflow zone behind them. The combined effect of these flow structures locally disrupts the originally stable laminar gas boundary layer, reducing its thickness. More importantly, the backflow zone behind the protrusions entrains the high-concentration gas from the main flow channel to the near-wall region, while simultaneously carrying away water vapor or liquid water from the wall. This convective mixing effect significantly enhances the gas transport rate in the normal direction of the gas diffusion layer, thus improving the mass transfer efficiency of the reactant gas.

[0027] Secondly, when liquid water flows through the flow-blocking protrusion, the protrusion cuts through the water film, breaking the continuous large water droplets into multiple smaller droplets. These smaller droplets have a larger surface area to volume ratio, making them easier to be entrained and transported by high-speed gas. The local low-pressure zone and turbulent pulsation generated behind the flow-blocking protrusion enhance the gas's ability to carry water droplets and reduce the adhesion of water droplets to the wall surface. Moreover, the flow-blocking protrusion itself occupies part of the flow channel cross-section, causing the gas velocity to increase locally on both sides of the flow-blocking protrusion. According to Bernoulli's principle, the pressure decreases where the velocity increases. This local pressure drop helps to draw the liquid water adhering to the surface of the gas diffusion layer out of the diffusion layer pores, effectively suppressing the occurrence of flooding. Attached Figure Description

[0028] Figure 1 This illustration shows a schematic diagram of a fuel cell provided in an embodiment of this application; Figure 2 This is a first-view view of a fuel cell flow channel plate provided in another embodiment of this application; Figure 3 This is a second perspective view of a fuel cell flow channel plate provided in another embodiment of this application; Figure 4 This diagram illustrates the coolant contact side of the fuel cell flow channel plate provided in an embodiment of this application. Figure 5 This application provides an embodiment of the invention. Figure 2 Enlarged view of section A; Figure 6 This diagram illustrates the gas contact side of the fuel cell flow channel plate provided in an embodiment of this application. Figure 7 A side view of the fuel cell flow channel plate provided in an embodiment of this application is shown; Figure 8 This application provides an embodiment of the invention. Figure 6 Sectional view of BB; Figure 9 This application provides an embodiment of the invention. Figure 6 Sectional view of AA; Figure 10 This is a schematic diagram of a conventional DC cathode flow channel plate; Figure 11 This is a schematic diagram of a variable cross-section cathode flow channel plate; Figure 12 A comparison of the polarization curves of three fuel cell stacks; Figure 13 This is a velocity distribution diagram within the gas diffusion layer of the first group of fuel cells; Figure 14 This is a velocity distribution diagram within the gas diffusion layer of the second group of fuel cells.

[0029] In the picture: 1. Cathode channel plate; 101. Groove bottom plate; 102. Raised top plate; 103. Connecting plate; 2. Anode channel plate; 3. Cathode gas diffusion layer; 4. Cathode gas catalyst layer; 5. Proton exchange membrane; 6. Anode catalyst layer; 7. Anode gas diffusion layer; 8. Coolant channel; 9. First flow blocking protrusion; 10. Second flow blocking protrusion; 11. Channel blocking protrusion; 111. First plate; 112. Second plate; 113. Third plate; 114. Fourth plate; 115. Fifth plate; 116. Sixth plate; 117. Seventh plate; 118. Groove; 119. Second coolant channel; 12. Channel groove; 13. Channel protrusion; 131. First coolant channel; 14. Flow gap. Detailed Implementation

[0030] The embodiments of this application will be described below with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. This application can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be understood that the preferred embodiments are only for illustrating this application and are not intended to limit the scope of protection of this application.

[0031] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this application. Therefore, the drawings only show the components related to this application and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0032] The embodiments of this application will be described below with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. This application can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be understood that the preferred embodiments are only for illustrating this application and are not intended to limit the scope of protection of this application.

[0033] To facilitate understanding of the embodiments of this application, the following will provide further explanation and description with reference to the accompanying drawings and specific embodiments. These embodiments do not constitute a limitation on the embodiments of this application.

[0034] The first aspect of this application provides a fuel cell flow channel plate, which has a coolant contact side and a gas contact side. The fuel cell flow channel plate includes a plurality of flow channel grooves 12, a plurality of flow channel protrusions 13, and a plurality of flow blocking protrusions. The plurality of flow channel grooves 12 are arranged along a first direction and are recessed towards the coolant contact side. A flow channel protrusion 13 is provided between any two adjacent flow channel grooves 12 and protrudes towards the gas contact side. The plurality of flow blocking protrusions are arranged along a second direction on the side of the flow channel grooves 12 facing the gas contact side. The second direction is the gas flow direction, and the first direction is perpendicular to the gas flow direction.

[0035] Specifically, the fuel cell flow channel plate includes multiple flow channel grooves 12, multiple flow channel protrusions 13, and multiple flow blocking protrusions. The multiple flow channel grooves 12 are arranged along a first direction and are recessed towards the coolant contact side. In other words, viewed from the gas contact side, the flow channel grooves 12 are downwardly recessed grooves with their bottom surfaces located near the coolant side. The multiple flow channel protrusions 13 are arranged alternately with the flow channel grooves 12, with a flow channel protrusion 13 between any two adjacent flow channel grooves 12, protruding towards the gas contact side. Therefore, viewed from the gas contact side, the plate surface exhibits a corrugated structure of alternating ridges and grooves. The protruding portions are the flow channel protrusions 13, and the recessed portions are the flow channel grooves 12 (i.e., the main channels for gas flow). The first direction is defined as the direction perpendicular to the gas flow direction, i.e., the width direction of the plate. The gas flow direction is defined as the second direction, typically the length direction of the plate, i.e., the direction from the common cavity of the reactant gas inlet to the common cavity of the outlet.

[0036] Furthermore, multiple flow blocking protrusions are arranged along the second direction on the side of the flow channel 12 facing the gas contact side (i.e., the bottom surface of the flow channel 12).

[0037] In actual operation of a fuel cell, the reactant gas (such as air on the cathode side or hydrogen on the anode side) enters the gas contact side of the electrode plate from the common cavity and flows along the second direction through the main channel formed by the flow channel groove 12. The gas diffusion layer (usually carbon fiber paper or carbon fiber cloth) covers the top surface of the flow channel protrusion 13 and partially extends into the space of the flow channel groove 12. The gas needs to diffuse or convection from the mainstream area in the flow channel groove 12 into the gas diffusion layer, and then reach the catalyst layer to participate in the electrochemical reaction. At the same time, the water generated by the electrochemical reaction (especially on the cathode side) exists in liquid or gaseous form in the gas diffusion layer and the flow channel, and needs to be carried away by the flowing gas in a timely manner.

[0038] In a typical direct-flow channel without flow-blocking protrusions, as gas flows along the bottom surface of the channel, a laminar boundary layer with a large velocity gradient forms near the bottom. Within this boundary layer, gas flow is primarily parallel to the bottom surface of the channel, and radial (perpendicular to the bottom) mass transfer mainly relies on molecular diffusion, which has a low diffusion rate. This causes a rapid decrease in reactant concentration at the inlet of the gas diffusion layer, while the generated water accumulates within the diffusion layer and is difficult to expel.

[0039] In contrast, in this embodiment, when gas flows through the flow-blocking protrusions within the flow channel 12, the protrusions act as physical barriers, forcing the gas to flow around them. This creates a stagnation zone in front of the protrusions, acceleration zones on either side, and a low-pressure backflow zone behind them. The combined effect of these flow structures locally disrupts the previously stable laminar gas boundary layer, reducing its thickness. More importantly, the backflow zone behind the protrusions entrains the high-concentration gas from the main flow zone of the channel 12 to the near-wall region (the interface between the top of the channel 12 and the diffusion layer), while simultaneously carrying away water vapor or liquid water from the wall. This convective mixing effect significantly enhances the gas transport rate in the normal direction to the gas diffusion layer, thus improving the mass transfer efficiency of the reactant gas.

[0040] Secondly, under high current density conditions, the water generated by the electrochemical reaction on the cathode side will condense into liquid water when it exceeds the saturation partial pressure of water vapor. This liquid water initially forms at the interface between the gas diffusion layer and the catalyst layer, gradually permeating into the interior of the gas diffusion layer, and finally exiting from the surface of the gas diffusion layer into the flow channel 12. In a typical direct-flow channel, liquid water often forms a continuous water film or a moving water column on the bottom surface of the flow channel 12. The water film hinders the exchange of matter between the gas and the diffusion layer, while the water column may completely block the flow channel, leading to insufficient gas supply in the downstream area, i.e., flooding. In this embodiment, when the liquid water flows through the flow-blocking protrusion, the protrusion cuts the water film, splitting the continuous large water droplets into multiple smaller droplets. These smaller droplets have a larger surface area to volume ratio, making them easier to be entrained and transported by high-speed gas. Secondly, the localized low-pressure zone and turbulent pulsations generated behind the flow-blocking protrusion enhance the gas's ability to carry water droplets, reducing the adhesion of water droplets to the wall surface. Furthermore, the flow-blocking protrusion itself occupies the cross-section of the flow channel groove 12, causing a localized increase in gas velocity on both sides of the protrusion. According to Bernoulli's principle, the pressure decreases where the velocity increases. This localized pressure drop helps to draw liquid water adhering to the surface of the gas diffusion layer out of the diffusion layer pores. Therefore, it effectively suppresses the occurrence of flooding.

[0041] It should be noted that, unlike the forced convection channels such as the serpentine channel (where the gas needs to make multiple 180° turns) and the cross-shaped channel (where the gas repeatedly enters and exits the ridge area), the flow blocking protrusion in this embodiment is small in size and does not change the overall direction of the channel. The gas does not need to change direction significantly when bypassing the flow blocking protrusion, and the local resistance coefficient is small. This means that the air compressor head required by the fuel cell system can be significantly reduced, thereby reducing the power consumption of the air compressor.

[0042] In a preferred embodiment, the flow blocking protrusion is also provided on the side of the flow channel protrusion 13 facing the gas contact side. That is, the flow blocking protrusion is provided on both the side of the flow channel groove 12 facing the gas contact side and the side of the flow channel protrusion 13 facing the gas contact side. For easy distinction, the flow blocking protrusion provided in the flow channel groove 12 is named the first flow blocking protrusion 9, and the flow blocking protrusion provided on the flow channel protrusion 13 is named the second flow blocking protrusion 10.

[0043] It should be noted that in the traditional flow channel, the top surface of the protrusion is completely in contact with the gas diffusion layer, and there is no gas flow in the area below the ridge (the porous medium area located directly below the protrusion 13 in the flow channel within the gas diffusion layer). The reactants can only enter the gas diffusion layer from the DC tank through molecular diffusion, resulting in low mass transfer efficiency and easy accumulation of generated water in this area.

[0044] In contrast, in this embodiment, as Figure 1 As shown, since the second flow blocking protrusion 10 protrudes from the flow channel protrusion 13, the gas diffusion layer will directly contact the second flow blocking protrusion 10. At this time, the gas diffusion layer no longer directly adheres to the surface of the flow channel protrusion 13, but forms a flow gap 14 between it and the surface of the flow channel protrusion 13.

[0045] Because the second flow-blocking protrusion 10 partially lifts the gas diffusion layer, the flow gap 14 formed between the top surface of the flow channel protrusion 13 and the gas diffusion layer (e.g., Figure 1 The gap formed between the flow channel protrusion 13 of the cathode flow channel plate 1 and the cathode gas diffusion layer 3 provides an additional flow path for gas. Gas can enter the ridge region (such as the region on the cathode gas diffusion layer 3 opposite to the flow channel protrusion 13) from the flow channel groove 12 through this flow gap 14. That is, under pressure, gas can directly enter the ridge region through the flow gap 14 between the top surface of the flow channel protrusion 13 and the gas diffusion layer, and then diffuse vertically or convect into the gas diffusion layer. Therefore, reactants can reach the catalyst layer surface in the ridge region more quickly, and the mass transfer efficiency is improved.

[0046] Secondly, after liquid water enters the gas diffusion layer from the catalyst layer, it can enter the flow gap 14 formed between the top surface of the flow channel protrusion 13 and the gas diffusion layer under the action of pressure difference or capillary force. Then, it is swept along the flow gap 14 by the airflow to the flow channel groove 12 and discharged with the mainstream gas. Since the airflow velocity in the flow gap 14 is small but much greater than the diffusion rate, the water removal efficiency is significantly higher than that of the pure diffusion process, giving the water in the ridge area a more direct discharge path and improving the drainage efficiency.

[0047] In addition, the geometry of the second flow blocking protrusion 10 itself can cut and break the water film or water droplets, preventing the formation of a continuous water film that blocks the flow gap 14, making it easier for water droplets to be entrained and transported by high-speed gas, effectively suppressing the occurrence of flooding.

[0048] In some embodiments, the flow blocking protrusion can be cylindrical, prismatic, hemispherical, or any other geometry capable of locally disturbing the gas flow. Preferably, the flow blocking protrusion is cylindrical. Furthermore, the diameter of the first flow blocking protrusion 9 is smaller than the width of the flow channel 12, therefore the first flow blocking protrusion 9 does not completely block the flow channel 12.

[0049] In this embodiment, as Figure 7 As shown, the fuel cell flow channel electrode body includes multiple recessed bottom plates 101 and multiple raised top plates 102. The recessed bottom plates 101 and raised top plates 102 are alternately connected in sequence along a first direction. Each raised top plate 102 is connected to two adjacent recessed bottom plates 101 via connecting plates 103. The space enclosed between the recessed bottom plate 101 and the two connected plates 103 forms a flow channel groove 12, and the raised top plate 102 and the two connected plates 103 constitute the aforementioned flow channel protrusion 13. Figure 8 As shown, the grooved bottom plate 101 protrudes towards the side away from the coolant contact side to form a first flow blocking protrusion 9, and the raised top plate 102 protrudes towards the side away from the coolant contact side to form a second flow blocking protrusion 10. That is, the grooved bottom plate 101, the raised top plate 102, the connecting plate 103, the first flow blocking protrusion 9, and the second flow blocking protrusion 10 are integrally formed. In this way, the integrated structure avoids weak points in the connection, improves the mechanical reliability of the electrode plate under pressure, and the connection between the grooved bottom plate 101 and the raised top plate 102 is smoothly transitioned, reducing the risk of stress concentration.

[0050] In some embodiments, the first flow blocking protrusion 9 and the second flow blocking protrusion 10 have the same height, such as Figure 8As shown, the height of the first flow blocking protrusion 9 in the thickness direction of the flow channel plate is h1, the height of the second flow blocking protrusion 10 in the thickness direction of the flow channel plate is h3, and the height of the protruding top plate 102 in the thickness direction of the flow channel plate is h2, where h1=h3>h2.

[0051] In some embodiments, such as Figure 6 As shown, along the second direction, the distance between any two adjacent flow blocking protrusions is a constant. That is, along the second direction, the distance d1 between two adjacent first flow blocking protrusions 9 is a constant, and similarly, along the second direction, the distance d1 between two adjacent second flow blocking protrusions 10 is a constant. When the distance d1 between adjacent flow blocking protrusions is a constant, the gas is subjected to periodic and uniform disturbances in the flow channel. The local backflow zones generated by each flow blocking protrusion are of similar size, resulting in consistent mass transfer enhancement and local pressure drop distribution along the flow path.

[0052] In some embodiments, the distance between any two adjacent flow-blocking protrusions along the second direction decreases sequentially by a fixed difference along that direction. It should be noted that during fuel cell operation, the reactant gas is gradually consumed along the flow path, resulting in a decrease in concentration. Simultaneously, the water generated by the electrochemical reaction accumulates downstream, increasing the risk of flooding. In this embodiment, by reducing the spacing between the flow-blocking protrusions downstream (i.e., increasing the number of flow-blocking protrusions per unit length), the boundary layer can be disrupted more frequently, generating a recirculation zone and pressure differential. This enhances the gas mixing and convection mass transfer efficiency in the downstream region and more effectively breaks down and carries away liquid water, preventing a sudden voltage drop in the outlet region due to insufficient mass transfer or flooding.

[0053] In some embodiments, the first flow-blocking protrusion 9 and the second flow-blocking protrusion 10 are arranged in multiple rows and columns, that is, the flow-blocking protrusions (the first flow-blocking protrusion 9 and the second flow-blocking protrusion 10) are distributed in a rectangular array to ensure the uniformity of gas mass transfer. Figure 6 As shown, in the first direction, in each column of flow blocking protrusions, the distance d2 between any two adjacent first flow blocking protrusions 9 and second flow blocking protrusions 10 is a constant value. In each row of first flow blocking protrusions 9, the distance d1 between two adjacent first flow blocking protrusions 9 is a constant value. In each row of second flow blocking protrusions 10, the distance between two adjacent second flow blocking protrusions 10 is also d1.

[0054] In this embodiment, the fuel cell flow channel plate includes multiple flow channel blocking protrusions 11. These protrusions 11 are arranged along a second direction within the flow channel groove 12, and a flow channel blocking protrusion 11 is provided between any two adjacent first flow blocking protrusions 9. In other words, within the flow channel groove 12, the first flow blocking protrusions 9 and the flow channel blocking protrusions 11 are arranged alternately along the gas flow direction. The flow channel blocking protrusions 11 protrude towards the side away from the coolant contact side, i.e., towards the gas contact side. Therefore, like the first flow blocking protrusions 9, the flow channel blocking protrusions 11 are protruding structures on the bottom surface of the flow channel groove 12. The two ends of the flow channel blocking protrusion 11 in the length direction (perpendicular to the gas flow direction) extend into the two flow channel protrusions 13 adjacent to the flow channel groove 12, that is, the flow channel blocking protrusion 11 is a long strip-shaped protrusion structure that spans the entire width of the flow channel groove 12, with its two ends resting on the flow channel protrusions 13 on both sides and integrated with the structure of the flow channel protrusions 13.

[0055] Since the flow channel plates have opposing coolant contact sides and gas contact sides, the protrusions on the gas contact side correspond to recesses (i.e., flow channel cavities) on the coolant contact side, and vice versa. Specifically, in this structure: a first coolant flow channel 131 is formed on the side of the flow channel protrusion 13 facing the coolant contact side (i.e., the back of the plate). This is because the flow channel protrusion 13 is a ridge-like structure protruding towards the gas contact side, and its back naturally forms a groove extending along the gas flow direction, allowing coolant to flow. Since the flow channel blocking protrusion 11 protrudes towards the gas contact side, a recess is also formed on its back (coolant contact side). The direction of this recess is consistent with the length direction of the flow channel blocking protrusion 11, i.e., extending along the first direction (perpendicular to the gas flow direction). Since the second coolant flow channel 119 is connected to the two adjacent first coolant flow channels 131, in other words, the two adjacent first coolant flow channels 131 are connected by multiple second coolant flow channels 119. In this way, the coolant is no longer confined to a single direction of flow, but can flow along a first direction within the first coolant flow channel 131, and along a second direction within the second coolant flow channel 119. For example... Figure 4 As shown, Figure 4 The arrows indicate the flow direction of the coolant. After flowing into the first coolant channel 131 in the first direction, the coolant can flow in the first coolant channel 131 in the second direction and flow into the next first coolant channel 131 through multiple second coolant channels 119.

[0056] It should be noted that traditional coolant flow channels are typically unidirectional parallel channels, where the coolant can only flow a long distance in one direction, resulting in high flow resistance. In this embodiment, however, the coolant is no longer limited to a single direction of flow but can flow within both a first and a second direction, redistributing flow rate and temperature to reduce overall flow resistance and enhance heat exchange with the electrode plates. Specifically, the first coolant flow channel 131 provides a main coolant channel along the second direction (in the same or opposite direction as the gas flow), while the second coolant flow channel 119 provides a transverse connecting channel along the first direction (perpendicular to the gas flow direction). The first and second coolant flow channels 131 and 119 are interconnected, forming a mesh-like flow network similar to a sieve or grid. When the coolant flows through this network, it can automatically select its path based on local resistance, flowing either linearly along the second direction or along the first direction. The coolant can continuously mix through the second coolant flow channel 119, redistributing flow rate and temperature to reduce overall flow resistance and enhance the heat exchange coefficient with the electrode plates.

[0057] In this embodiment, a groove 118 is provided on the side of the flow channel blocking protrusion 11 away from the coolant contact side. The groove 118 is recessed towards the coolant contact side, and its projection along the thickness direction of the fuel cell flow channel plate falls into the flow channel groove 12. It should be noted that the groove 118 (recessed towards the coolant side) at the top of the flow channel blocking protrusion 11 forms a local depression channel on the gas side. When gas flows through the entire flow channel blocking protrusion 11, the groove 118 provides an additional flow cross section, allowing some gas to pass over the groove 118, thereby avoiding excessive local pressure drop caused by the flow channel blocking protrusion 11 completely blocking the flow channel groove 12. At the same time, the sidewalls and bottom corners of the groove 118 can cut and break up the liquid water film or droplets, promoting water dispersion and making it easier for the water to be carried away by the airflow.

[0058] In this embodiment, the flow channel blocking protrusion 11 is in Figure 6The cross section in the CC direction includes a first plate 111, a second plate 112, a third plate 113, a fourth plate 114, a fifth plate 115, a sixth plate 116, and a seventh plate 117 connected in sequence. The first plate 111 and the seventh plate 117 are respectively connected to the raised top plates 102 on both sides, forming the two end support parts of the flow channel blocking protrusion 11. The second plate 112 and the sixth plate 116 have the same height, forming the high platform area at both ends of the flow channel blocking protrusion 11. The fourth plate 114 is lower than the second plate 112, forming the bottom surface of the groove 118. The third plate 113 connects the second plate 112 and the fourth plate 114. The fifth plate 115 connects the sixth plate 116 and the fourth plate 114. The third plate 113 and the fifth plate 115 form the two side walls of the groove 118. The cross-sectional shape causes the flow channel blocking protrusion 11 to have a profile that is low in the middle and high at both ends on the gas contact side, thereby forming a downwardly recessed groove 118 structure on the top of the flow channel blocking protrusion 11.

[0059] Furthermore, although the flow channel blocking protrusion 11 extends into the flow channel protrusion 13 at both ends, it does not completely cover the top surface of the entire flow channel protrusion 13 along the first direction. For example... Figure 5 As shown, there is an unoccupied planar area on the top surface of the flow channel protrusion 13 between two adjacent flow channel blocking protrusions 11. The gap between the two adjacent flow channel blocking protrusions 11 provides a flow path for the gas along the gas flow direction. This gap, together with the second flow blocking protrusion 10, forms a two-dimensional interconnected mesh airflow passage, which enhances the flow flexibility of the gas in the plate plane.

[0060] In this embodiment, as Figure 9 As shown, in the thickness direction of the fuel cell flow channel plates, the height of the second plate 112 and the sixth plate 116 is h5, the height of the fourth plate 114 is h4, and the height of the raised top plate 102 is h2, wherein h5 > h4, h5 > h2, and h5 is the same as the heights h1 and h3 of the flow blocking protrusion.

[0061] In one specific embodiment, the second plate 112, the fourth plate 114 and the sixth plate 116 have the same length, and the length of the second plate 112 is the same as the diameter of the flow blocking protrusion.

[0062] In summary, the flow channel plate of this fuel cell has at least the following advantages: First, the concave and convex structures (flow blocking protrusions, flow channel grooves 12, and flow channel blocking protrusions 11) on the gas contact side of the fuel cell flow channel plate work together to continuously change the fluid flow area and the destruction of the boundary layer, thereby increasing the disturbance and turbulence of the gas and enhancing the mass transfer efficiency.

[0063] Second, when the gas flows through the first flow blocking protrusion 9, local contraction and expansion occur; when it flows through the flow channel blocking protrusion 11, the gas in the flow channel groove 12 will experience sudden contraction and expansion effects when it flows through the groove 118 of the flow channel blocking protrusion 11 and through the gap between two adjacent flow channel blocking protrusions 11. This change in depth and cross-section causes the gas to generate significant velocity components in both the flow direction (second direction) and the normal direction, which enhances convective mixing and improves the mass transfer efficiency of the gas to the gas diffusion layer.

[0064] Third, when liquid water flows through the flow-blocking protrusion, the protrusion will cut the water film, splitting the continuous large water droplets into multiple small water droplets, making them easier to be entrained and transported by high-speed gas.

[0065] Fourth, the coolant is no longer limited to flowing in one direction, but can flow in both the first and second directions, redistributing flow rate and temperature, thereby reducing overall flow resistance and enhancing heat exchange with the plates.

[0066] The second aspect of this application provides a flow channel structure in which the flow channel plates constituting the flow channel structure are all fuel cell flow channel plates of the above embodiments.

[0067] It should be noted that in actual fuel cells, the fuel cell flow channel plates are divided into cathode flow channel plate 1 and anode flow channel plate 2. Cathode flow channel plate 1 is used to transport air (oxygen), and its gas contact side is adjacent to the cathode gas diffusion layer 3. Anode flow channel plate 2 is used to transport hydrogen, and its gas contact side is adjacent to the anode gas diffusion layer 7.

[0068] This flow channel structure includes a coolant flow channel 8 and a gas flow channel. The gas flow channel includes a cathode gas flow channel and an anode gas flow channel. The coolant flow channel 8 is formed between the side of the cathode flow channel plate 1 facing the coolant contact side and the side of the anode flow channel plate 2 facing the coolant contact side. In other words, when the cathode flow channel plate 1 and the anode flow channel plate 2 are placed back to back (with their coolant contact sides facing each other), the space between them constitutes the coolant flow channel 8. Since both plates have concave and convex structures corresponding to the gas contact side (i.e., the first coolant flow channel 131 and the second coolant flow channel 119) on their coolant contact sides, these structures together form a three-dimensional coolant flow network. A cathode gas flow channel is formed between the side of the cathode flow channel plate 1 facing the gas contact side and the cathode gas diffusion layer 3. Specifically, the cathode gas diffusion layer 3 (usually carbon fiber paper or carbon fiber cloth) covers the gas contact side of the cathode flow channel plate 1, and the gap between the cathode flow channel plate 1 and the cathode gas diffusion layer 3 is the cathode gas flow channel. Similarly, an anode gas channel is formed between the side of the anode channel plate 2 facing the gas contact side and the anode gas diffusion layer 7.

[0069] Because the coolant contact surfaces of the cathode channel plate 1 and the anode channel plate 2 are not flat, but have concave and convex features corresponding to those of the gas contact side, the protrusions on the gas contact side (such as the channel protrusion 13, the first flow blocking protrusion 9, the second flow blocking protrusion 10, and the channel blocking protrusion 11) correspond to recesses (i.e., cavities in the coolant channel) on the coolant contact side, while the recesses on the gas contact side (such as the channel groove 12) correspond to protrusions on the coolant contact side. When the cathode channel plate 1 and the anode channel plate 2 are combined back-to-back, the features on their coolant sides complement each other to form a mesh-like flow network similar to a sieve or grid. The coolant flow mesh structure of this embodiment allows the coolant to flow freely in both the gas flow direction (second direction) and the gas flow perpendicular direction (first direction), that is, to achieve flow in any direction within a two-dimensional plane.

[0070] Thus, in traditional unidirectional direct-flow cooling structures, the coolant must flow along a long and tortuous single-direction channel, resulting in a long path, numerous bends, and high flow resistance due to localized blockages. The water pump requires significant power to maintain the flow rate. The mesh structure of this embodiment provides multiple parallel flow paths for the coolant, significantly reducing overall flow resistance. Furthermore, the mesh flow prevents the coolant from flowing through a straight channel in a single laminar state; instead, it continuously splits, merges, and changes direction, generating a strong lateral secondary flow. This secondary flow disrupts the thermal boundary layer of the coolant on the wall, significantly increasing the heat transfer coefficient between the wall and the fluid. This means that the same heat dissipation effect can be achieved with a smaller coolant flow rate, or a lower plate temperature can be achieved while maintaining the same flow rate.

[0071] It should be noted that since the coolant can flow in any direction within a two-dimensional plane, the common cavity for the coolant inlet and outlet of the electrode does not need to be aligned with or perpendicular to the gas inlet / outlet. For example, the coolant inlet and outlet can both be located on the same short side of the electrode, while the gas inlet and outlet can be located on the long side, without interfering with each other. This flexibility is very beneficial for the overall layout design of the fuel cell stack, as it simplifies manifold design and adapts to various electrode structures and single-cell structures.

[0072] In addition, since both the cathode gas channel and the anode gas channel adopt the same multi-layered flow field structure, when the gas flows through the first flow blocking protrusion 9, its downstream backflow zone disrupts the laminar boundary layer, entrains the mainstream high-concentration gas to the near-wall region, enhances normal convection mass transfer, enhances the gas transmission rate in the normal direction of the gas diffusion layer, and improves the mass transfer efficiency of the reactant gas. At the same time, the second flow blocking protrusion 10 lifts the gas diffusion layer to form a flow gap 14, providing an additional flow path for the gas, allowing the gas to enter the ridge region laterally, and the reactants can reach the catalyst layer surface in the ridge region more quickly, thus improving the mass transfer efficiency. Moreover, both the first flow blocking protrusion 9 and the second flow blocking protrusion 10 can effectively suppress the occurrence of flooding by splitting continuous large water droplets into multiple small water droplets.

[0073] A third aspect of this application provides a fuel cell that employs the flow channel structure, cathode gas diffusion layer 3, cathode gas catalyst layer 4, proton exchange membrane 5, anode catalyst layer 6, and anode gas diffusion layer 7 of the above embodiments.

[0074] To verify the performance of the fuel cell flow channel plate of the present invention in an actual fuel cell stack, a comparative test was conducted in this embodiment. The test subjects were three groups of fuel cell stacks. The effective active area, membrane electrode assembly, assembly pressure and operating conditions of each group of stacks were exactly the same. The only difference was the structure of the cathode flow channel plate.

[0075] The first group (the present invention group) uses the cathode flow channel plate 1 of the above embodiment. The second group (the conventional DC channel group) uses a conventional parallel DC channel structure for the cathode flow channel plate, such as... Figure 10 As shown, the DC grooves and protrusions are arranged alternately, and the bottom surface of the DC grooves is smooth without any flow-blocking protrusions or turbulence structures.

[0076] The cathode flow channel plate of the third group (variable cross-section flow channel group) adopts the instructions. Figure 11 The variable cross-section flow channel structure shown has periodic contraction and expansion sections inside the flow channel, which causes the gas flow area to change repeatedly along the flow direction, thereby forcibly generating disturbances and eddies.

[0077] All three fuel cell stacks use the same conventional parallel flow channel structure for their anode flow channel plates (to avoid the influence of anode-side variables), and the membrane electrode assemblies (including the cathode gas diffusion layer, cathode catalyst layer, proton exchange membrane, anode catalyst layer, and anode gas diffusion layer) are prepared in the same batch to ensure that the catalyst layer loading, diffusion layer porosity, and thickness are consistent, and to ensure that the three fuel cell stacks operate under exactly the same operating conditions.

[0078] These three fuel cell stacks were tested according to the parameters recorded in Table 1 below, and the specific operating conditions were as follows:

[0079] Table 1 The test results are summarized in Table 2, and the polarization curves are compared in the appendix. Figure 12 .

[0080]

[0081] Table 2 Table 2 and appendices Figure 12 Test results show that, across the entire current density range, the output voltage of the present invention group is higher than that of the conventional DC channel group, especially in the high current density (≥2000 mA / cm²) region, where the voltage advantage of the present invention group is more obvious. Compared with the variable cross-section channel group, the present invention group also has a higher voltage at the same current density, and the cathode voltage drop is significantly lower than that of the variable cross-section channel group.

[0082] To further illustrate the gas mass transfer effect inside the multi-layered micro-column flow field, the simulation results of the transport of reactant gas to the gas diffusion layer in the embodiment of the present invention and the variable cross-section flow field were compared. Figure 13 and Figure 14 The velocity distribution diagrams within the gas diffusion layer of the fuel cell of the present invention and the second group (fuel cell with variable cross-section flow channel cathode flow channel plate) are shown respectively. As can be seen from the velocity distribution diagrams, the velocity distribution within the gas diffusion layer that cooperates with the cathode flow channel plate 1 of this embodiment is more uniform, resulting in higher overall mass transfer efficiency (average velocity), better mass transfer efficiency, lower mass transfer impedance, and better reaction uniformity, thus improving the power generation efficiency of the fuel cell stack.

[0083] The above experimental results fully demonstrate the advantages of the fuel cell of the present invention in reducing flow resistance, improving high electrical density performance, and improving mass transfer uniformity.

[0084] It should be noted that the terms "one implementation," "embodiment," "exemplary embodiment," and "some embodiments" used in the specification indicate that the described embodiment may include a specific feature, structure, or characteristic, but not every embodiment necessarily includes that specific feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Moreover, when a specific feature, structure, or characteristic is described in connection with an embodiment, implementing such a feature, structure, or characteristic in conjunction with other embodiments, whether explicitly described or not, is within the knowledge scope of those skilled in the art.

[0085] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to imply a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0086] The above embodiments are merely preferred embodiments provided to fully illustrate this application, and the scope of protection of this application is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on this application are all within the scope of protection of this application.

Claims

1. A fuel cell flow channel plate, characterized in that, The fuel cell flow channel plate has a coolant contact side and a gas contact side. The fuel cell flow channel plate includes a plurality of flow channel grooves (12), a plurality of flow channel protrusions (13) and a plurality of flow blocking protrusions. The plurality of flow channel grooves (12) are arranged along a first direction and the flow channel grooves (12) are recessed toward the coolant contact side. A flow channel protrusion (13) is provided between any two adjacent flow channel grooves (12) and the flow channel protrusion (13) protrudes toward the gas contact side. Multiple flow-blocking protrusions are arranged along the second direction on the side of the flow channel groove (12) facing the gas contact side; The second direction is the gas flow direction, and the first direction is perpendicular to the gas flow direction.

2. The fuel cell flow channel plate according to claim 1, characterized in that, The flow blocking protrusion includes a first flow blocking protrusion (9) and a second flow blocking protrusion (10). A plurality of first flow blocking protrusions (9) are arranged along a second direction on the side of the flow channel groove (12) facing the gas contact side, and a plurality of second flow blocking protrusions (10) are arranged along a second direction on the side of the flow channel protrusion (13) facing the gas contact side.

3. A fuel cell flow channel plate according to claim 2, characterized in that, It includes multiple flow channel blocking protrusions (11), which are arranged in the flow channel groove (12) along the second direction, and one flow channel blocking protrusion (11) is provided between any two adjacent first flow blocking protrusions (9). The flow channel blocking protrusions (11) protrude to the side away from the coolant contact side. The two ends of the flow channel blocking protrusion (11) extend into the two flow channel protrusions (13) adjacent to the flow channel groove (12).

4. A fuel cell flow channel plate according to claim 3, characterized in that, The flow channel blocking protrusion (11) has a groove (118) on the side away from the coolant contact side. The groove (118) is recessed towards the coolant contact side, and the projection of the groove (118) along the thickness direction of the fuel cell flow channel plate falls into the flow channel groove (12).

5. A fuel cell flow channel plate according to claim 4, characterized in that, It includes multiple grooved bottom plates (101) and multiple raised top plates (102), the grooved bottom plates (101) and the raised top plates (102) are sequentially and alternately connected along a first direction, and each raised top plate (102) is connected to two adjacent grooved bottom plates (101) by a connecting plate (103); the space enclosed between the grooved bottom plates (101) and the two connected connecting plates (103) forms the flow channel groove (12); the grooved bottom plates (101) protrude toward the side away from the coolant contact side to form the first flow blocking protrusion (9), and the raised top plates (102) protrude toward the side away from the coolant contact side to form the second flow blocking protrusion (10).

6. A fuel cell flow channel plate according to claim 5, characterized in that, The side of the first flow blocking protrusion (9) away from the groove bottom plate (101) and the side of the second flow blocking protrusion (10) away from the protrusion top plate (102) are located on the same side; The side of the flow channel blocking protrusion (11) away from the coolant contact side is coplanar with the side of the first flow blocking protrusion (9) away from the groove bottom plate (101).

7. A fuel cell flow channel plate according to claim 1, characterized in that, Along the second direction, the distance between any two adjacent flow-blocking protrusions is a constant. Alternatively, the distance between two adjacent flow-blocking protrusions along the second direction decreases sequentially along that direction by a fixed difference.

8. A fuel cell flow channel plate according to claim 2, characterized in that, A flow gap (14) is formed between the flow channel protrusion (13) and the gas diffusion layer opposite it.

9. A fuel cell flow channel plate according to claim 4, characterized in that, The flow channel protrusion (13) forms a first coolant flow channel (131) on the side facing the coolant contact side, and the flow channel blocking protrusion (11) forms a second coolant flow channel (119) on the side facing the coolant contact side. The second coolant flow channel (119) is connected to the two adjacent first coolant flow channels (131).

10. A fuel cell flow channel plate according to claims 1-9, characterized in that, The flow-blocking protrusion can be any one of a cylinder, rhombus, square, or teardrop shape.

11. A flow channel structure, characterized in that, The fuel cell flow channel plate includes any one of claims 1-10, wherein the fuel cell flow channel plate is divided into a cathode flow channel plate (1) and an anode flow channel plate (2), and the flow channel structure includes a coolant flow channel (8) and a gas flow channel. The coolant flow channel (8) is formed between the side of the cathode flow channel plate (1) facing the coolant contact side and the side of the anode flow channel plate (2) facing the coolant contact side. The gas flow channel is formed between the side of the cathode flow channel plate (1) facing the gas contact side and the cathode gas diffusion layer (3), and the gas flow channel is formed between the side of the anode flow channel plate (2) facing the gas contact side and the anode gas diffusion layer (7).

12. A fuel cell, characterized in that, It includes a flow channel structure as described in claim 11, a cathode gas diffusion layer (3), a cathode gas catalyst layer (4), a proton exchange membrane (5), an anode catalyst layer (6), and an anode gas diffusion layer (7).

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