A radial flow field bipolar plate and fuel cell stack structure

Abstract

The present invention discloses a radial flow field bipolar plate and a fuel cell stack structure, belonging to the technical field of fuel cells, comprising a bipolar plate body, an anode side groove and a cathode side groove are respectively provided on both sides of the bipolar plate body, a cathode air inlet is provided in the middle of the bipolar plate body, and a connecting tube is connected to one side of the cathode air inlet; a plurality of anode ribs distributed in multi-stage arcs are provided on the bottom surface of the anode side groove, and two anode gas holes are provided on the side wall of the anode side groove; a plurality of cathode ribs distributed in multi-stage radials are provided on the bottom surface of the cathode side groove, a cathode air inlet is provided on the side wall of the connecting tube, and a cathode gas outlet is provided through the side wall of the cathode side groove. The structure is simple and compact, the stack is convenient, the gas flow state is effectively improved, a more uniform gas distribution is achieved, the reaction in the entire stack is ensured to occur uniformly, and the efficiency and performance of the stack are improved; it helps to reduce the pressure drop during gas flow, so that the operation of the stack is more energy-saving and efficient.

Description

Technical Field

[0001] The present invention belongs to the technical field of fuel cells, and in particular to a radial flow field bipolar plate and a fuel cell stack structure. Background Art

[0002] A fuel cell is a highly efficient energy conversion device that directly converts chemical energy into electrical energy. It consists of a cathode, an anode, and an electrolyte, and produces electricity and water through the electrochemical reaction of hydrogen and oxygen. Fuel cells are clean, efficient, and low-emission, and are considered one of the important options for future energy. In a fuel cell, hydrogen passes through the cathode as a fuel, and oxygen passes through the anode. The two react under the condition that the electrolyte is conductive, generating electron flow and ion flow, and ultimately generating electricity. This electrochemical reaction has almost no emissions, only water vapor and heat, and is environmentally friendly. The efficiency of fuel cells is as high as 40% to 60%, which is much higher than that of traditional internal combustion engines. Fuel cells are widely used in transportation, aerospace, home energy, and mobile devices. In the automotive field, fuel cell vehicles have the advantages of zero emissions, long driving range, and fast refueling, and are one of the important directions for the development of future automobiles. At the same time, fuel cells can also be used in energy storage systems to provide storage and utilization solutions for renewable energy.

[0003] A fuel cell stack is a system composed of multiple fuel cell units. Stacking multiple units can achieve higher power output. Fuel cell stacks are widely used in driving electric vehicles, power generation and other fields, and are an important part of clean energy technology.

[0004] The fuel cell stacks that have been developed today include parallel flow PEMFC stacks, cross-flow PEMFC stacks, etc., all of which have disadvantages to a certain extent, such as uneven gas distribution, long intake path, large pressure drop, limited reaction area, and uneven gas mixing. Summary of the invention

[0005] In order to solve the problem that the currently developed fuel cell stacks include parallel flow PEMFC stacks, cross-flow PEMFC stacks, etc., which all have shortcomings such as uneven gas distribution, long intake path, large pressure drop, limited reaction area, uneven gas mixing, etc. to a certain extent, the present invention provides a radial flow field bipolar plate and a fuel cell stack structure.

[0006] On the one hand, the present invention is achieved through the following technical solutions:

[0007] A radial flow field bipolar plate comprises a bipolar plate body, wherein the two sides of the bipolar plate body are respectively an anode side and a cathode side; an anode side groove and a cathode side groove are respectively provided on the anode side and the cathode side, a cathode air inlet is provided in the middle of the bipolar plate body, and a connecting tube is connected to the side of the cathode air inlet close to the cathode side, and the connecting tube can be inserted with the end of the cathode air inlet close to the anode side; a plurality of anode ribs distributed in a multi-stage arc shape with the center of the bipolar plate body as the center are provided on the bottom surface of the anode side groove, and two anode gas holes are provided on the side wall of the anode side groove; a plurality of cathode rib columns distributed in a multi-stage radial shape with the center of the bipolar plate body as the center are provided on the bottom surface of the cathode side groove, a plurality of cathode air inlet holes are provided on the side wall of one end of the connecting tube close to the bipolar plate body, and a plurality of cathode gas outlet holes are penetrated through the side wall of the cathode side groove.

[0008] A further improvement of the present invention is that the anode ribs are distributed in a plurality of fan-shaped areas centered on the center of the bipolar plate body, adjacent fan-shaped areas form a radial path for anode gas, and adjacent inner and outer anode ribs form a circumferential path for anode gas.

[0009] A further improvement of the present invention is that the two anode air holes are arranged opposite to each other.

[0010] A further improvement of the present invention is that the cathode ribs are in a teardrop-shaped structure directed outward.

[0011] A further improvement of the present invention is that the volume of the cathode ribs gradually increases from the inside to the outside and is distributed in a staggered manner.

[0012] A further improvement of the present invention is that the cathode air inlet holes correspond one-to-one to the innermost cathode ribs.

[0013] A further improvement of the present invention is that the cathode gas outlet holes are arranged corresponding to the two outermost cathode ribs.

[0014] Another aspect of the present invention is achieved through the following technical solutions:

[0015] A fuel cell stack structure comprises a plurality of radial flow field bipolar plates as described above; a plurality of positioning holes along the axial direction are opened on the outer side of the bipolar plate body, bolts for stacking and pressing the plurality of bipolar plate bodies are passed through the positioning holes; membrane electrodes are sealed and pressed between adjacent bipolar plate bodies.

[0016] A further improvement of the present invention is that two axial anode gas channels are opened on the outer side of the bipolar plate body, and the two anode gas channels are respectively connected to the two anode gas holes.

[0017] A further improvement of the present invention is that one end of the cathode air inlet channel close to the anode side is in a stepped hole structure, in which a sealing ring is provided that can be press-fitted and sealed with a connecting tube on an adjacent bipolar plate body.

[0018] It can be seen from the above technical solutions that the beneficial effects of the present invention are:

[0019] The fuel cell stack structure is formed by stacking multiple radial flow field bipolar plates, and the membrane electrode is sealed and pressed between the two adjacent bipolar plate bodies; oxygen is introduced into the anode side groove from an anode gas hole, and is separated by the multi-stage arc-shaped anode ribs to avoid diffusion along the same path, which is conducive to uniform diffusion of oxygen, ensuring the uniformity of gas flow, avoiding water aggregation caused by uneven gas distribution, and not prone to flow channel blockage and flooding. The reacted (or unreacted) gas is discharged through another anode gas hole; hydrogen is introduced into the middle of the cathode side groove through the cathode inlet and the corresponding cathode inlet, and is separated and blocked by the multi-stage radially distributed cathode ribs, similar to the shock wave diffusion process, which is more conducive to uniform distribution of gas and ensures a larger and more uniform reaction area. The overall structure is simple and compact, the stack is convenient, the reliability is high, it can effectively improve the flow state of the gas, achieve a more uniform gas distribution, help ensure uniform reaction in the entire stack, and improve the efficiency and performance of the stack; at the same time, it helps to reduce the pressure drop during gas flow, has less energy loss, and makes the operation of the stack more energy-saving and efficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solution of the present invention, the accompanying drawings required for use in the description will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0021] Figure 1 It is a schematic diagram of the anode side structure of a specific embodiment of the present invention.

[0022] Figure 2 It is a schematic diagram of the cathode side structure of a specific embodiment of the present invention.

[0023] Figure 3 It is a schematic diagram of the positive projection of the anode side of a specific embodiment of the present invention.

[0024] Figure 4 It is a schematic diagram of the cathode side orthographic projection of a specific embodiment of the present invention.

[0025] Figure 5 This is a schematic diagram of the distribution of cathode ribs, cathode air inlet holes, and cathode air outlet holes in a specific implementation manner of the present invention.

[0026] Figure 6 It is a schematic diagram of the structure of a fuel cell stack according to a specific embodiment of the present invention.

[0027] Figure 7 It is a schematic top view of a fuel cell stack according to a specific embodiment of the present invention.

[0028] Figure 8 for Figure 7 Schematic diagram of the local section along the AA direction.

[0029] Fig. 9 for Figure 7 Schematic diagram of the local section along the BB direction.

[0030] In the accompanying drawings: 100, bipolar plate body, 11, anode side groove, 111, anode rib, 112, anode gas hole, 12, cathode side groove, 121, cathode rib, 122, cathode air inlet, 123, cathode air outlet, 13, bump, 14, anode gas channel, 15, positioning seat, 16, positioning hole, 17, cathode air inlet, 18, connecting tube, 19, membrane electrode slot, 200, membrane electrode, 300, sealing ring. DETAILED DESCRIPTION

[0031] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings in this specific embodiment. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of them. Based on the embodiments in this patent, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this patent.

[0032] like Figure 1-5 As shown, the present invention discloses a radial flow field bipolar plate, comprising a circular plate-shaped bipolar plate body 100, wherein the two sides (upper and lower end surfaces) of the bipolar plate body 100 are respectively an anode side and a cathode side; an anode side groove 11 and a cathode side groove 12 are respectively provided on the anode side (upper side) and the cathode side (lower side); a circular cathode air inlet 17 is provided in the middle of the bipolar plate body 100, the cathode air inlet 17 is arranged along its axis, and a cylindrical connecting tube 18 is connected to one side (lower side) of the cathode air inlet 17 close to the cathode side, and the connecting tube 18 can be plugged and sealed with one end of the cathode air inlet 17 close to the anode side (electrical The bottom surface of the anode side groove 11 is provided with a plurality of anode ribs 111 distributed in a multi-stage arc shape with the center of the bipolar plate body 100 as the center, and the side wall of the anode side groove 11 is provided with two anode gas holes 112; the bottom surface of the cathode side groove 12 is provided with a plurality of cathode ribs 121 distributed in a multi-stage radial shape with the center of the bipolar plate body 100 as the center, and the side wall of the connecting tube 18 close to one end (root) of the bipolar plate body 100 is provided with a plurality of cathode gas inlet holes 122 connected with the cathode gas inlet channel 17, and the side wall of the cathode side groove 12 is provided with a plurality of cathode gas outlet holes 123.

[0033] A fuel cell stack structure is formed by stacking a plurality of radial flow field bipolar plates, and a membrane electrode 200 is sealed and pressed between two adjacent bipolar plate bodies 100; oxygen is introduced into the anode side groove 11 from an anode gas hole 112, and is separated by the multi-stage arc-shaped anode ribs 111 to avoid diffusion along the same path, which is conducive to uniform diffusion of oxygen, ensures uniformity of gas flow, avoids water accumulation caused by uneven gas distribution, and is less likely to cause flow channel blockage and flooding. The reacted (or unreacted) gas is discharged through another anode gas hole 112; hydrogen is introduced into the middle of the cathode side groove 12 through the cathode inlet 17 and the corresponding cathode inlet 122, and is separated and blocked by the multi-stage radially distributed cathode ribs 121, which is similar to the shock wave diffusion process, which is more conducive to uniform distribution of gas and ensures a larger and more uniform reaction area. The overall structure is simple and compact, the stack is easy to assemble, and the reliability is high. It can effectively improve the flow state of the gas and achieve a more uniform gas distribution, which helps to ensure that the reaction occurs evenly throughout the stack, thereby improving the efficiency and performance of the stack. At the same time, it helps to reduce the pressure drop during gas flow, has less energy loss, and makes the operation of the stack more energy-efficient and efficient.

[0034] like Figure 1 , 3 As shown, the anode ribs 111 are distributed in several (6) fan-shaped areas centered on the center of the bipolar plate body 100, and adjacent fan-shaped areas form a radial path for anode gas, and adjacent inner and outer anode ribs 111 form a circumferential path for anode gas. A structure similar to a Tesla valve is formed, which effectively guides the gas flow while reducing the impact of gas backflow, forming multiple step-by-step diffusion annular flow intervals, and the anode gas radial path and the anode gas circumferential path are interconnected, effectively avoiding gas diffusion along the same path, which is conducive to uniform gas diffusion, ensuring uniform gas flow, avoiding water accumulation caused by uneven gas distribution, and not prone to flow channel blockage and flooding.

[0035] Furthermore, the two anode gas holes 112 are arranged opposite to each other. The two anode gas holes 112 are located at the outer ends of the anode gas radial path, and the width of the anode gas radial path is smaller than the size of the connecting tube 18. Figure 1 , 3 As shown, during use, oxygen enters from an anode gas hole 112, passes through the opposite anode gas radial path to the connecting tube 18 in the middle position, and diffuses through the adjacent anode gas circumferential path. Since the size of the connecting tube 18 is larger than the width of the anode gas radial path, it can completely block the gas, allowing the gas to diffuse to the surrounding anode gas radial path and anode gas circumferential path, and be discharged from another anode gas hole 112, thereby achieving uniform gas distribution and ensuring uniform reaction.

[0036] The anode gas holes 112 are in the shape of rectangle, circle or other polygons.

[0037] like Figure 2 , 4 As shown in FIG. 5 , the cathode ribs 121 are evenly spaced in each ring, providing a uniform outward diffusion path for hydrogen, achieving a more uniform hydrogen distribution, and helping to ensure that the reaction occurs evenly throughout the fuel cell stack.

[0038] Furthermore, the cathode rib 121 is in a water drop-shaped structure with the direction facing outwards. The water drop-shaped cathode rib 121 effectively reduces the occurrence of turbulence when the gas diffuses in the flow field, and enables the laminar flow phenomenon to be better maintained.

[0039] Furthermore, the volume of the cathode ribs 121 gradually increases from the inside to the outside, and is staggered. The cathode ribs 121 of the outer layer (outer stage) effectively block the outflow of the gas from the inner layer (inner stage) (the outer layer cathode ribs 121 block the outward extension direction of the channel between the adjacent cathode ribs 121 of the inner layer), so that the gas diffuses to both sides, ensuring the uniformity of gas distribution and the uniformity of reaction.

[0040] The number of cathode ribs 121 can be adjusted according to the area of ​​the electrode plate. The number is proportional to the area of ​​the electrode plate. The larger the area of ​​the electrode plate, the greater the number of cathode ribs.

[0041] Furthermore, the cathode gas inlet holes 122 correspond one-to-one to the innermost cathode ribs 121. The gas coming out of the cathode gas inlet holes 122 is blocked by the innermost (innermost) cathode ribs 121 to achieve preliminary diffusion and ensure uniform gas distribution.

[0042] Furthermore, the width of the cathode gas inlet hole 122 is not greater than the width of the innermost layer (innermost stage) cathode rib 121 , thereby ensuring that the innermost stage cathode rib 121 effectively blocks and diffuses the gas entering the cathode gas inlet hole 122 .

[0043] The cathode air inlet hole 122 is in a rectangular, circular or other polygonal shape.

[0044] Furthermore, the cathode gas outlet holes 123 are arranged corresponding to the two outermost cathode ribs 121, thereby extending the reaction path of the gas and making the reaction more uniform.

[0045] like Figure 6-9 As shown, the present invention also discloses a fuel cell stack structure, comprising a plurality of the radial flow field bipolar plates as described above; four positioning seats 15 are provided in an annular array on the outer side of the bipolar plate body 100, and an axial positioning hole 16 is opened on the positioning seat 15, and bolts for stacking and pressing the plurality of bipolar plate bodies 100 are passed through the positioning hole 16; a membrane electrode 200 is sealed and pressed between adjacent bipolar plate bodies 100.

[0046] like Figure 4 , 6-9, when the bipolar plates are stacked, the membrane electrode 200 is positioned and pressed into the membrane electrode slot 19, and the anode side groove 11 and the cathode side groove 12 of the adjacent bipolar plate body 100 are divided; multiple bipolar plate bodies 100 are stacked and fastened by bolts passing through the corresponding positioning holes 16, the anode gas hole 112 on the uppermost bipolar plate body 100 is blocked, and the cathode air inlet 17 on the lowermost bipolar plate body 100 is blocked (or directly set as a blocking plate structure); oxygen is introduced into the anode side groove 11 from an anode gas hole 112, and is divided into multiple arc-shaped parts. The anode ribs 111 of the distribution are separated to avoid diffusion along the same path, which is conducive to uniform diffusion of oxygen, ensuring the uniformity of gas flow, avoiding water aggregation caused by uneven gas distribution, and not prone to flow channel blockage and flooding. The reacted (or unreacted) gas is discharged through another anode gas hole 112; hydrogen passes through the cathode inlet 17 and the corresponding cathode inlet 122 into the middle of the cathode side groove 12, and is separated and blocked by the multi-stage radially distributed cathode ribs 121, similar to the shock wave diffusion process, which is more conducive to the uniform distribution of gas and ensures a larger and more uniform reaction area. The overall structure is simple and compact, the stack is convenient, the reliability is high, and it can effectively improve the flow state of the gas, achieve a more uniform gas distribution, help ensure that the reaction in the entire stack occurs evenly, and improve the efficiency and performance of the stack; at the same time, it helps to reduce the pressure drop during gas flow, has less energy loss, and makes the operation of the stack more energy-saving and efficient.

[0047] like Figure 1 , 2 As shown in FIG. 8 , two opposite protrusions 13 are provided on the outer side of the bipolar plate body 100, and an axial anode gas channel 14 is opened on the protrusion 13. The anode gas channel 14 is connected to the corresponding anode gas hole 112. Oxygen is introduced through one anode gas channel 14 and discharged through the other anode gas channel 14. The structure is simple, compact, and easy to implement.

[0048] Among them, Figure 1 , 8 As shown in Figures 9 and 10, the end of the cathode inlet 17 near the anode side is a stepped hole structure, in which a sealing ring 300 is provided that can be pressed and sealed with the connecting cylinder 18 on the adjacent bipolar plate body 100. The connecting cylinder 18 is inserted into the corresponding stepped hole and the sealing ring 300 is pressed to achieve effective sealing of the adjacent bipolar plate bodies 100. The sealing ring 300 is a plastic sealing ring, which ensures the sealing performance and effectively prevents the overpressure deformation of the MEA between the bipolar plate bodies 100.

[0049] The radial flow field bipolar plate and fuel cell stack structure are formed by stacking multiple radial flow field bipolar plates to form a fuel cell stack structure, and a membrane electrode 200 is sealed and pressed between two adjacent bipolar plate bodies 100; oxygen is introduced into the anode side groove 11 from an anode gas hole 112, and is separated by the multi-stage arc-shaped anode ribs 111 to avoid diffusion along the same path, which is conducive to uniform diffusion of oxygen, ensures uniformity of gas flow, avoids water accumulation caused by uneven gas distribution, and is less likely to cause flow channel blockage and flooding. The reacted (or unreacted) gas is discharged through another anode gas hole 112; hydrogen is introduced into the middle of the cathode side groove 12 through the cathode inlet 17 and the corresponding cathode inlet 122, and is separated and blocked by the multi-stage radially distributed cathode ribs 121, which is similar to the shock wave diffusion process, which is more conducive to uniform distribution of gas and ensures a larger and more uniform reaction area. The overall structure is simple and compact, the stack is easy to assemble, and the reliability is high. It can effectively improve the flow state of the gas and achieve a more uniform gas distribution, which helps to ensure that the reaction occurs evenly throughout the stack, thereby improving the efficiency and performance of the stack. At the same time, it helps to reduce the pressure drop during gas flow, has less energy loss, and makes the operation of the stack more energy-efficient and efficient.

[0050] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the various embodiments can be referenced to each other.

[0051] The terms "upper", "lower", "outer side", "inner side", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish the relative relationship in position if they exist, and do not need to be qualitative. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described here can be implemented in an order other than those illustrated or described here. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions.

[0052] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A radial flow field bipolar plate, characterized in that: The invention comprises a bipolar plate body (100), wherein two sides of the bipolar plate body (100) are respectively an anode side and a cathode side; the anode side and the cathode side are respectively provided with an anode side groove (11) and a cathode side groove (12); a cathode air inlet (17) is provided in the middle of the bipolar plate body (100); a connecting tube (18) is connected to a side of the cathode air inlet (17) close to the cathode side; the connecting tube (18) can be plugged into an end of the cathode air inlet (17) close to the anode side; a plurality of bipolar plate body-shaped grooves are provided on the bottom surface of the anode side groove (11); The anode ribs (111) are arranged in a multi-stage arc shape with the center of the bipolar plate body (100) as the center, and the side wall of the anode side groove (11) is provided with two anode gas holes (112); the bottom surface of the cathode side groove (12) is provided with a plurality of cathode rib columns (121) which are arranged in a multi-stage radial shape with the center of the bipolar plate body (100) as the center, a plurality of cathode gas inlet holes (122) are arranged on the side wall of one end of the connecting tube (18) close to the bipolar plate body (100), and a plurality of cathode gas outlet holes (123) are provided through the side wall of the cathode side groove (12); The anode ribs (111) are distributed in a plurality of fan-shaped areas centered on the center of the bipolar plate body (100), adjacent fan-shaped areas form a radial path for anode gas, and adjacent inner and outer anode ribs (111) form a circumferential path for anode gas; The cathode ribs (121) are arranged in annular intervals at each stage.

2. The radial flow field bipolar plate according to claim 1, characterized in that: The two anode gas holes (112) are arranged opposite to each other.

3. The radial flow field bipolar plate according to claim 1, characterized in that: The cathode rib (121) is in a water drop-shaped structure directed outward.

4. The radial flow field bipolar plate according to claim 1, characterized in that: The cathode ribs (121) gradually increase in volume from the inside to the outside and are distributed in a staggered manner.

5. The radial flow field bipolar plate according to claim 1, characterized in that: The cathode air inlet holes (122) correspond one-to-one to the innermost cathode ribs (121).

6. The radial flow field bipolar plate according to claim 1, characterized in that: The cathode gas outlet holes (123) are arranged corresponding to the cathode ribs (121) at the two outermost stages.

7. A fuel cell stack structure, characterized in that: The invention comprises a plurality of radial flow field bipolar plates as claimed in any one of claims 1 to 6; a plurality of positioning holes (16) are provided on the outside of the bipolar plate body (100) along its axial direction, and bolts for stacking and pressing the plurality of bipolar plate bodies (100) are passed through the positioning holes (16); and membrane electrodes (200) are sealed and pressed between adjacent bipolar plate bodies (100).

8. The fuel cell stack structure according to claim 7, characterized in that: Two axial anode gas channels (14) are provided on the outside of the bipolar plate body (100), and the two anode gas channels (14) are respectively connected to the two anode gas holes (112).

9. The fuel cell stack structure according to claim 7, characterized in that: One end of the cathode air inlet (17) close to the anode side is in a stepped hole structure, in which a sealing ring (300) capable of being press-fitted and sealed with a connecting cylinder (18) on an adjacent bipolar plate body (100) is provided.

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