Blocking type pin-fin fuel cell flow field plate and fuel cell

Abstract

The invention belongs to the field of fuel cell structures, and particularly relates to a blocking type pin-fin fuel cell flow field plate and a fuel cell, the blocking type pin-fin fuel cell flow field plate comprises a bipolar plate and a flow channel, one end of the bipolar plate is provided with a gas inlet, and the other end is provided with a gas outlet; a plurality of rows of blocking structures are arranged in the flow channel, a plurality of supporting columns are arranged in each row of blocking structures, the supporting columns are connected through blocking walls, the supporting columns in every two adjacent rows of blocking structures are arranged in a staggered mode, and the blocking walls are lower than the supporting columns. By adjusting the distribution of reactants in the fuel cell, the oxygen concentration at two corners far away from the diagonal line and the gas inlet / outlet is improved, so that the oxygen concentration of an anoxic region under a low-voltage working condition is effectively improved. The blocking wall is periodically arranged to interfere the flowing of reaction gas, so that the flow velocity change which is periodically vertical to the bottom surface of a flow field is brought, the mass transfer of oxygen is promoted, the drainage capacity is improved, and the negative influence of excessive accumulation of liquid water on oxygen diffusion is effectively avoided.

Description

Technical Field

[0001] The present invention relates to the field of fuel cell structures, and more particularly, to a blocked pin-fin fuel cell flow field plate and a fuel cell. Background Art

[0002] As a clean energy source, hydrogen is widely used in fuel cells. It has the advantages of small size, high power density, and low operating temperature, making it an important research direction. The bipolar plate is a key component of the fuel cell and plays a crucial role in the oxygen transport and water drainage processes in the fuel cell.

[0003] There are various types of flow field plates, including traditional serpentine, parallel, pin-fin, and interdigitated flow fields, as well as new types of flow fields such as biomimetic flow fields and three-dimensional flow fields. Among them, the serpentine flow field achieves a uniform electrolyte distribution through a meandering flow channel design, but its long flow path results in significant pressure drop losses; the parallel flow field, although simple in structure and low in pumping power, has the problem of uneven distribution of reaction gases, easily forming "dead zones" at the end of the flow channel, leading to a decrease in local mass transfer efficiency; the pin-fin flow field enhances the turbulent effect through periodically distributed support columns, while the interdigitated flow field induces forced convection using discontinuous flow channels. Both can improve the mass transfer effect, but the process complexity is relatively high.

[0004] New types of flow fields, such as biomimetic flow fields, draw on biological structural characteristics, for example, mimicking the fractal network of plant veins or the multi-stage branching system of animal lung bronchi, which can achieve efficient mass transfer while reducing flow resistance; three-dimensional flow fields break the planar limitation of traditional two-dimensional flow channels through three-dimensional flow channel designs (such as wavy, spiral, or honeycomb structures), significantly increasing the specific surface area and water drainage efficiency. Research shows that these innovative designs can increase the limiting current density of fuel cells and enhance the water management ability. However, their complex topological structures pose severe challenges to precision machining technologies. Especially when manufacturing large-size bipolar plates, problems such as dimensional tolerance control of micron-scale flow channels, flow-solid coupling stress distribution, and large-scale production costs have not been fully resolved.

[0005] It is worth noting that the parasitic power ratio of the serpentine flow field is high, while the parallel flow field, although having a low pumping power ratio in stationary power station applications, requires an auxiliary gas circulation device to compensate for mass transfer defects. The latest technical route shows that the biomimetic-pin-fin composite flow field combining 3D printing of gradient pore flow fields and topological optimization algorithms may become the key direction to break through the existing performance bottlenecks.

[0006] The performance of the pin fin flow field is between that of the parallel flow field and the serpentine flow field. The pumping power is similar to that of the parallel flow field and much lower than that of the serpentine flow field. However, in the conventional pin fin flow field plate, there is a problem of uneven reactant distribution outside the diagonal region connecting the gas inlet and outlet. At the same time, due to the low flow velocity, there is also difficulty in draining water. Specifically, first, at low voltages, the lack of oxygen problem in the region deviating from the diagonal region leads to concentration loss, and the problem becomes more serious the farther away from the diagonal, especially in the two corners without gas inlets and outlets. Second, due to the low pressure drop of the pin fin flow field plate and the low gas flow velocity, it will lead to difficulty in draining water at low voltages, and the liquid water under the support posts is likely to accumulate rapidly. Summary of the Invention

[0007] To solve the above problems, the present invention provides a blocked pin fin fuel cell flow field plate and a fuel cell. The blocked pin fin fuel cell flow field plate reduces the excessive flow of reaction gas near the diagonal by adding blocking walls in the pin fin flow field plate, diverts part of the reaction gas to the region far from the diagonal, improves the uniformity of reactant distribution through the adjustment of multiple layers of blocking walls, and at the same time, by the sudden narrowing of the flow channel by the blocking wall, the flow velocity of the reaction gas in the flow channel is increased, and the oxygen delivery capacity and drainage capacity in the region near the outlet are improved.

[0008] To achieve the above object, the technical solution of the present invention is: a blocked pin fin fuel cell flow field plate, including a bipolar plate and a flow channel, wherein a gas inlet is opened at one end of the bipolar plate, and a gas outlet is opened at the other end; multiple rows of blocking structures are provided in the flow channel, multiple support posts are arranged in each row of blocking structures, and the support posts are connected by blocking walls, and the support posts in adjacent two rows of blocking structures are arranged in a staggered manner, and the height of the blocking wall is lower than the height of the support posts.

[0009] Further, the support posts at both ends in adjacent two rows of blocking structures are connected to the side surface of the bipolar plate or the blocking wall is connected to the side surface of the bipolar plate; the bottom surface and side surface of the flow channel are in direct contact with the bipolar plate, and the top surface of the flow channel is in direct contact with the gas diffusion layer.

[0010] Further, at both ends of the blocking structure in the row close to the gas inlet, the support posts are connected to the side surface of the bipolar plate, and at both ends of the blocking structure in the next row along the gas flow direction, the blocking walls are connected to the side surface of the bipolar plate, and so on in a cycle, and at both ends of the row close to the gas outlet, the support posts are connected to the side surface of the bipolar plate.

[0011] Further, the bottom surface of the support post is in direct contact with the bipolar plate, and the top surface of the support post is in direct contact with the gas diffusion layer.

[0012] Further, the bottom surface of the blocking wall is in direct contact with the bipolar plate, and the top surface of the blocking wall is in direct contact with the gas diffusion layer.

[0013] Further, the gas outlet and the gas inlet are opened in the diagonal direction of the bipolar plate.

[0014] Further, the surfaces of the support posts and the blocking walls are provided with ceramic coatings.

[0015] Further, the width of the flow channel is 21 mm, the height is 1 mm, and the length is 53 mm. The support posts are all cubes with a length, width, and height of 1 mm, and the length and width of the blocking walls are both 1 mm, and the height is 0.8 mm.

[0016] The present invention also provides a fuel cell using the blocked pin-fin fuel cell flow field plate.

[0017] Compared with the prior art, the present invention has the following beneficial effects: By adjusting the distribution of reactants in the fuel cell, in the main flow direction parallel to the bottom surface of the flow field along the gas inlet and outlet directions, and in the direction perpendicular to the main flow direction and parallel to the bottom surface of the flow field, the present invention significantly increases the oxygen concentration at two corners far from the diagonal and the gas inlet and outlet, thereby effectively improving the oxygen concentration in the oxygen-deficient area under low-voltage conditions. By periodically setting the blocking walls to interfere with the flow of reaction gases, a periodic change in the flow velocity perpendicular to the bottom surface of the flow field is brought about, which not only promotes the mass transfer of oxygen but also enhances the drainage ability, effectively avoiding the negative impact of excessive accumulation of liquid water on oxygen diffusion. The periodic narrowing of the flow channel caused by the blocking walls increases the flow velocity of the reaction gases in the main flow direction, further enhancing the mass transfer ability of oxygen and the drainage ability, and increasing the oxygen concentration in the area near the outlet. By arranging the support posts in a cross pattern, it is ensured that the reaction gases can directly impact the support posts, thereby improving the oxygen mass transfer and drainage ability under the support posts. Finally, by increasing the average oxygen concentration and minimizing the oxygen-deficient area, the output power of the fuel cell is significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] To more intuitively and clearly show the embodiments of this specification, some embodiments will be briefly described with reference to the drawings. Obviously, the following drawings are only some embodiments of this specification, and for those of ordinary skill in the art, all other embodiments fall within the protection scope of the present invention without creative work.

[0019] Figure 1 is a schematic structural diagram of a blocked pin-fin fuel cell flow field plate according to an embodiment of the present invention; Figure 2 is a side view and a top view of a blocked pin-fin fuel cell flow field plate according to an embodiment of the present invention; Figure 3 is a schematic structural diagram of a conventional parallel flow field plate according to a comparative example of the present invention; Figure 4 is a schematic structural diagram of a conventional pin-fin flow field plate according to a comparative example of the present invention; Figure 5are the polarization curves and power density curves of the fuel cells of the embodiments and comparative examples of the present invention; Figure 6 is the oxygen molar concentration distribution nephogram at the interface between the microporous layer and the catalyst layer of the fuel cells of the embodiments and comparative examples of the present invention at a voltage of 0.45V; Figure 7 is the liquid saturation distribution nephogram at the interface between the microporous layer and the catalyst layer of the fuel cells of the embodiments and comparative examples of the present invention at a voltage of 0.45V; Figure 8 is the comparison chart of the changes in pressure drop and net power at a voltage of 0.45V when the widths of the fuel cells of the embodiments and comparative examples of the present invention are 38mm and 53mm respectively; Figure 9 is the velocity distribution nephogram in the thickness direction near the interface between the flow channel and the diffusion layer of the fuel cells with a blocked pin fin fuel cell flow field plate having four different blocked wall widths (0.2mm, 1mm, 1.6mm, and 2mm) at a voltage of 0.45V on the premise that the position of the blocked wall of the present invention remains unchanged; Figure 10 is the comparison of the average oxygen molar concentration and net power at the interface between the microporous layer and the catalyst layer at a voltage of 0.45V of the fuel cells with a blocked pin fin fuel cell flow field plate having four different blocked wall widths (0.2mm, 1mm, 1.6mm, and 2mm) at a voltage of 0.45V on the premise that the position of the blocked wall of the present invention remains unchanged; Figure 11 are the polarization curves and power density curves of the fuel cells with a blocked pin fin fuel cell flow field plate having three different overall widths, i.e., cycle periods (2mm, 4mm, and 8mm), and the pin fin flow field plate fuel cells with the relative widths of the blocked wall, support posts, and flow channels remaining unchanged in the present invention; Figure 12 is the velocity distribution nephogram in the thickness direction near the interface between the microporous layer and the catalyst layer at a voltage of 0.45V of the fuel cells with a blocked pin fin fuel cell flow field plate having three different overall widths, i.e., cycle periods (2mm, 4mm, and 8mm), and the pin fin flow field plate fuel cells with the relative widths of the blocked wall, support posts, and flow channels remaining unchanged in the present invention; Figure 13 is the comparison of the average oxygen molar concentration and net power at the interface between the microporous layer and the catalyst layer at a voltage of 0.45V of the fuel cells with a blocked pin fin fuel cell flow field plate having three different overall widths, i.e., cycle periods (2mm, 4mm, and 8mm), and the pin fin flow field plate fuel cells with the relative widths of the blocked wall, support posts, and flow channels remaining unchanged in the present invention.

[0020] In the attached drawings, 1 is the gas outlet; 2 is the support column; 3 is the blocking wall; 4 is the bipolar plate; 5 is the flow channel; 6 is the gas inlet. Detailed implementation mode

[0021] Next, in combination with the accompanying drawings of the embodiments of this specification, the specific technical solutions in the embodiments will be analyzed in detail and described comprehensively. Obviously, the following description is only a part of this embodiment and does not cover all embodiments. Based on the embodiments of the present invention, all other embodiments that can be thought of by those of ordinary skill in the art without creative work belong to the protection scope of the present invention.

[0022] It should be noted that unless otherwise defined, all technical terms and scientific terms used in the embodiments of this specification and the accompanying drawings should be interpreted according to the general understanding within the technical field to which the present invention belongs. At the same time, the terms "including" and "having" and any variations thereof in the embodiments of this specification and the accompanying drawings represent a non-exclusive inclusion relationship. Embodiment 1. The present invention provides a blocked pin-fin fuel cell flow field plate, including a bipolar plate 4 and a flow channel 5. One end of the bipolar plate 4 is the gas inlet 6, and the other end is the gas outlet 1; a plurality of support columns 2 are provided in the flow channel 5, and the support columns 2 are connected to each other through a blocking wall 3. The bottom surface and side surface of the flow channel 5 are in direct contact with the bipolar plate 4, and the top surface of the flow channel 5 is in direct contact with the gas diffusion layer. The support columns 2 have various shapes. The bottom surface of the support column 2 is in direct contact with the bipolar plate 4, the top surface of the support column 2 is in direct contact with the gas diffusion layer, and the side surfaces of some support columns 2 are in direct contact with the bipolar plate. The bottom surface of the blocking wall 3 is in direct contact with the bipolar plate 4, the top surface of the blocking wall 3 is in direct contact with the gas diffusion layer, and the height of the blocking wall 3 is lower than that of the support column 2; the support columns 2 with various shapes are in direct contact with the bipolar plate 4 and the gas diffusion layer through the bottom surface and the top surface respectively, enhancing the structural stability of the flow channel 5, and at the same time providing uniform support for the gas diffusion layer to avoid local collapse. The contact of the side surfaces of some support columns with the bipolar plate can further improve the current conduction efficiency; the height of the blocking wall 3 is lower than that of the support column, forming a local blocking effect, forcing the reaction gas to change the flow path in the flow field, prolonging the residence time and increasing the contact probability with the catalytic layer, thereby improving the utilization rate of the reaction gas; the bottom surface and side surface of the flow field are in direct contact with the bipolar plate, and the top surface is in contact with the gas diffusion layer, optimizing the heat conduction and current transmission paths, reducing the contact resistance, and at the same time ensuring the mechanical strength; through the flow field layout from the inlet 6 to the outlet 1, combined with the distribution of the support columns and the blocking wall, a controllable gas flow channel is formed, avoiding gas short circuit and promoting the uniform distribution of reactants.

[0023] The support columns 2 are arranged at equal intervals in a plurality of planes perpendicular to the gas inlet 6. Among them, the sides of the first and last support columns 2 in the first row of support columns close to the gas inlet 6 are in direct contact with the bipolar plate 4, while there is a gap between the sides of the first and last support columns 2 in the second row and the bipolar plate 4. The arrangement pattern of the third row of support columns 2 is the same as that of the first row of support columns 2, and the arrangement pattern of the fourth row of support columns 2 is the same as that of the second row of support columns 2. The subsequent rows are arranged in a regular cycle, and the spacing between each row is uniform. Each row of support columns 2 is connected by a blocking wall 3; if there is a gap between the sides of the support columns 2 at both ends of a certain row and the side of the bipolar plate 4, a blocking wall 3 is arranged in the gap to connect the support column 2 and the bipolar plate 4. The sides of the first and last support columns 2 in odd rows such as the first row and the third row are in direct contact with the bipolar plate 4, while there is a gap between the sides of the first and last support columns in even rows such as the second row and the fourth row and the bipolar plate, forming a periodically alternating contact mode, which can guide the gas to flow regularly in a circuitous manner in the flow field, balance the gas distribution and reduce the flow dead zone; when there is a gap between the two ends of a certain row of support columns and the bipolar plate, the support column and the bipolar plate are connected by the blocking wall 3, which not only maintains the structural integrity but also forms a local flow resistance to prevent the gas from escaping along the short path of the side wall; all the support columns are arranged at equal intervals in the direction perpendicular to the gas inlet, and the spacing between each row is uniform. Combining with the periodically cyclic arrangement pattern, it ensures the stability of the gas pressure gradient in the flow field and avoids the sudden change of the local flow velocity caused by uneven arrangement; each row of support columns is connected to each other by a blocking wall, forming a coherent transverse blocking structure, which jointly constructs a three-dimensional gas guiding network with the longitudinal alternating contact / gap design to strengthen the active control ability of the fluid.

[0024] Preferably, the width of the flow field is 21 mm, the height is 1 mm, and the length is 53 mm. The support columns are all cubes with a length, width, and height of 1 mm, and the length and width of the blocking wall are both 1 mm, and the height is 0.8 mm.

[0025] Optionally, a ceramic coating is provided on the surfaces of the support columns 2 and the blocking wall 3; if a conductive ceramic is used, it can maintain a low contact resistance between the support column and the gas diffusion layer while preventing corrosion. When only insulating ceramic is used on the side of the blocking wall and a conductive coating or bare substrate is retained on the top surface of the support column, the corrosion protection and electrical properties are balanced.

[0026] Figure 1 The structural schematic diagram of a blocked pin-fin fuel cell flow field plate in an embodiment of the present invention is shown. Figure 2These are the side view and top view of the flow field plate. Through the flow limiting effect of the blocking wall 3, the blocked pin fin fuel cell flow field plate diverts the reactants concentrated near the diagonal connecting the gas inlet 6 and the gas outlet 1 to areas far from the diagonal, and realizes the uniform distribution of the reactants by repeatedly setting the blocking wall 3. At the same time, the multiple sharp contractions of the flow channels caused by the blocking wall 3 make the reaction gas accelerate multiple times, improving the transport ability of the reaction gas and effectively increasing the oxygen concentration in the latter half of the flow field.

[0027] The present invention also provides a fuel cell using the blocked pin fin fuel cell flow field plate. Since the structure of this flow field plate is simple and the processing cost is low, the blocked pin fin fuel cell flow field plate can be applied to the anode and cathode bipolar plates. Next, the present invention will be described in detail through three-dimensional multiphase numerical simulation, and fuel cells using conventional parallel flow field plates and conventional pin fin flow field plates will be used as a comparison. The structures of the parallel flow field plate and the pin fin flow field plate are as Figure 3 and Figure 4 shown. The shape and arrangement of the support columns in the pin fin flow field plate are exactly the same as those in the Figure 1 illustrated embodiment. The three fuel cells operate under exactly the same operating conditions, where air with a relative humidity of 100% is introduced into the cathode, hydrogen with a relative humidity of 100% is introduced into the anode, and the excess ratios of the anode and cathode are set to 2 and 1.5 respectively.

[0028] The polarization curves and power density curves of the three fuel cells are as Figure 5 shown. At a voltage of 0.45V, the oxygen molar concentration distribution at the interface between the microporous layer and the catalytic layer of the three fuel cells is as Figure 6 shown, and the liquid saturation distribution is as Figure 7 shown. It can be seen from Figure 5 that compared with the parallel flow field, the pin fin flow field has a certain advantage in output power under low voltage and high current conditions. On the basis of the pin fin flow field plate, the blocked pin fin fuel cell flow field plate further expands the advantage compared with the traditional parallel flow field. When the voltage is 0.45V, the output power of the fuel cell using the blocked pin fin fuel cell flow field plate is increased by 52% compared with the fuel cell using the parallel flow field plate. Analyzing the reasons, it can be seen from Figure 6 that after adding the blocking wall to the pin fin flow field plate, two main functions are achieved: one is to make the reaction gas more evenly distributed by restricting gas flow; the other is to increase the velocity of the reaction gas in the vertical direction through the guiding effect of the blocking wall, promoting the mass transfer between the flow channel and the porous medium region, thereby enhancing oxygen transport and increasing the oxygen concentration in the outlet region of the flow channel, almost eliminating the oxygen-deficient area. At the same time, it can be seen from Figure 7It can be seen that the liquid saturation distribution of the blocked pin-fin fuel cell flow field plate is similar to that of the traditional pin-fin flow field plate, and no additional water accumulation occurs due to the increase in current density and water production. This indicates that the blocked pin-fin fuel cell flow field plate has a stronger drainage ability compared to the traditional pin-fin flow field plate.

[0029] To further illustrate the role of the blocking wall in distributing the gas flow in the blocked pin-fin fuel cell flow field plate, two flow field plate widths of 38 mm and 53 mm were additionally selected. On the premise that the structural logic remains unchanged, the fuel cells of the embodiment and the comparative example of the present invention were extended to the flow field plates of these two widths, and the changes in the fuel cell pressure drop and net power were compared when the voltage was 0.45 V. Figure 8 The results show that as the width of the flow field plate increases, the net power of the traditional parallel flow field plate and the pin-fin flow field plate gradually decreases, while the net power of the blocked pin-fin fuel cell flow field plate gradually increases. This is because as the width of the flow field plate and the active area increase, the distribution of oxygen in the traditional parallel flow field plate and the pin-fin flow field plate becomes more uneven, resulting in more serious local oxygen deficiency problems and power losses. In contrast, the blocking wall of the blocked pin-fin fuel cell flow field plate can effectively alleviate this problem through its function of regulating the gas flow distribution. As the size of the flow field plate increases, the maximum power of the blocked pin-fin fuel cell flow field plate also increases.

[0030] To illustrate the role of setting the blocking wall 3 in the blocked pin-fin fuel cell flow field plate, with the left side of the blocking wall 3 fixed, four cases were set by changing the thickness of the blocking wall 3: in Case 1, the width of all blocking walls was 0.2 mm; in Case 2, the width of all blocking walls was 1 mm; in Case 3, the width of all blocking walls was 1.6 mm; in Case 4, the width of all blocking walls was 2 mm. For these four cases, the fuel cell was numerically simulated under the same operating conditions to obtain the simulation results of three types of blocked fuel cell channels. Figure 9 Shows the velocity distribution in the thickness direction at the interface between the flow channel and the diffusion layer under the four cases when the voltage is 0.45 V, Figure 10 Shows the comparison of the average oxygen concentration at the interface between the microporous layer and the catalytic layer and the net power of the fuel cell under the four cases when the voltage is 0.45 V.

[0031] From Figure 9 It can be seen that the blocking wall 3 mainly changes the oxygen transport process by affecting the flow of the reaction gas. The wider the width of the blocking wall 3, the narrower the width of the flow channel 5, and the more intense the vertical flow of the reaction gas in the flow channel, thereby effectively promoting the oxygen transport and increasing the oxygen molar concentration and reaction intensity below the flow channel and under the rib. Figure 9 and Figure 10It shows that although Case 4 with a plugging wall 3 width of 2 mm has a higher pressure than Case 3 with a plugging wall 3 width of 1.6 mm, Case 3 exhibits the highest average oxygen concentration, oxygen effective mass transfer coefficient, and net power among the four cases. This is because although the plugging wall 3 in Case 4 has a larger width, the plugging walls 3 are connected to each other, resulting in the disappearance of the flow channels between the plugging walls 3. The plugging walls in the middle of the flow field cannot cooperate with the flow channels to effectively promote oxygen transfer, thereby reducing the oxygen effective mass transfer coefficient and increasing the pressure, ultimately leading to a lower net power than in Case 3. Therefore, simply plugging the flow field does not necessarily improve the oxygen mass transfer ability. The plugging wall 3 should cooperate with the flow channels between the plugging walls 3 to more effectively promote oxygen transfer by disturbing the flow of the reaction gas, thereby improving the output performance of the fuel cell.

[0032] To further illustrate the role of the support pillar 2, plugging wall 3, and flow channel 5 coupling structure in the blocked pin-fin fuel cell flow field plate, three cases were set by equally increasing or decreasing the width (i.e., the cycle period) of this coupling structure while keeping the ratio of the support pillar 2, plugging wall 3, and flow channel 5 fixed: In Case 1 (BNFF-C2), the width of all coupling structures is 2 mm; in Case 2 (BNFF-C4), the width of all coupling structures is 4 mm; in Case 3 (BNFF-C8), the width of all coupling structures is 8 mm. For the three cases, the fuel cell was numerically simulated under the same operating conditions to obtain the simulation results of the three blocked fuel cell flow channels. Figure 11 Shows the polarization curves and power density curves of the three cases and the pin-fin flow field plate fuel cell (NFF). Figure 12 Shows the oxygen distribution at the junction of the catalyst layer and the microporous layer of the three cases and the pin-fin flow field plate fuel cell when the voltage is 0.45 V. Figure 13 Shows the comparison of the average oxygen concentration and the net power of the fuel cell at the interface between the microporous layer and the catalyst layer of the three cases and the pin-fin flow field plate fuel cell when the voltages are 0.4 V, 0.45 V, and 0.5 V respectively.

[0033] From Figure 11 It can be seen that the cycle period mainly affects the fuel cell performance under low voltage and high current conditions. The smaller the cycle period, the stronger the output performance of the fuel cell. When the voltage is 0.45 V, BNFF-C2 achieves the highest output power among all cases under all operating conditions, with a 22% power increase compared to the pin-fin flow field plate fuel cell. Analyzing the reasons, from Figure 12It can be seen that, compared with NFF, the coupling structure can effectively improve the oxygen transport capacity of the fuel cell. After the width of the coupling structure becomes narrower and the number increases, the oxygen mass transfer capacity for the areas below the flow channel 5 and below the support column 2 can be improved simultaneously. From BNFF-C8 to BNFF-C2, the area with sufficient oxygen below the flow channel 5 gradually expands, and at the same time, the problem of less oxygen below the support column 2 is solved. Except for the area below some of the support columns 2 downstream of the flow channel, the oxygen concentration in almost all other areas below the support column 2 exceeds 1.2 mol / m 3 . It can also be seen from Figure 13 that the oxygen concentration of BNFF-C2 at various voltages is the highest among the four cases, and thus the highest net power among the four cases is obtained. Therefore, the narrower and more numerous the coupling structure is, the stronger the performance of the blocked pin fin flow field plate fuel cell is. However, after the coupling structure becomes too narrow, the processing difficulty will increase, and at the same time, the structural strength will also deteriorate. Therefore, the optimization of the cycle period in the present invention stops at 2 mm.

[0034] The above is only the description of the preferred embodiments of the present invention and does not constitute a limitation to the present invention. For those skilled in the art, various modifications and changes can be made to the foregoing embodiments without departing from the spirit and principle of the present invention. Therefore, any modification, equivalent replacement or improvement made to the present invention shall be covered within the protection scope of the present invention.

Claims

1. A blocked pin-fin fuel cell flow field plate, characterized in that It includes a bipolar plate (4) and a flow channel (5). One end of the bipolar plate is provided with a gas inlet (6), and the other end is provided with a gas outlet (1); multiple rows of blocking structures are arranged in the flow channel (5), and multiple support columns (2) are arranged in each row of blocking structures. The support columns (2) are connected by a blocking wall (3). The support columns (2) in adjacent two rows of blocking structures are arranged in a staggered manner, and the height of the blocking wall (3) is lower than the height of the support columns (2).

2. The blocked pin fin fuel cell flow field plate according to claim 1, wherein The support columns (2) at both ends in adjacent two rows of blocking structures are connected to the side surface of the bipolar plate (4) or the blocking wall (3) is connected to the side surface of the bipolar plate (4); the bottom surface and the side surface of the flow channel (5) are in direct contact with the bipolar plate (4), and the top surface of the flow channel (5) is in direct contact with the gas diffusion layer.

3. The blocked pin fin fuel cell flow field plate according to claim 2, wherein For the blocking structure in the row close to the gas inlet (6), the support columns (2) at both ends are connected to the side surface of the bipolar plate (4). For the next row of blocking structure along the gas flow direction, the blocking wall (3) at both ends is connected to the side surface of the bipolar plate (4). This cycle continues until the row close to the gas outlet (1) where the support columns (2) are connected to the side surface of the bipolar plate (4).

4. The blocked pin fin fuel cell flow field plate according to claim 1, wherein The bottom surface of the support column (2) is in direct contact with the bipolar plate (4), and the top surface of the support column (2) is in direct contact with the gas diffusion layer.

5. The blocked pin fin fuel cell flow field plate according to claim 1, characterized in that, The bottom surface of the blocking wall (3) is in direct contact with the bipolar plate (4), and the top surface of the blocking wall (3) is in direct contact with the gas diffusion layer.

6. The blocked pin fin fuel cell flow field plate according to claim 1, characterized in that, The gas outlet (1) and the gas inlet (6) are provided in the diagonal direction of the bipolar plate (4).

7. The blocked pin fin fuel cell flow field plate according to claim 1, wherein Along the gas flow direction, the heights of the support columns (2) and the blocking wall (3) change in a stepped manner.

8. The blocked pin fin fuel cell flow field plate according to claim 1, characterized in that, The surfaces of the support columns (2) and the blocking wall (3) are provided with ceramic coatings.

9. The blocked pin fin fuel cell flow field plate according to claim 1, wherein The width of the flow channel (5) is 21 mm, the height is 1 mm, and the length is 53 mm. The support columns (2) are all cubes with side lengths of 1 mm for length, width, and height. The length and width of the blocking wall (3) are both 1 mm, and the height is 0.8 mm.

10. A fuel cell, characterized in that, Adopt the blocked pin-fin fuel cell flow field plate according to any one of claims 1 to 9.

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