Fuel cell bipolar plate with bionic flow field and fuel cell

Abstract

The invention provides a fuel cell bipolar plate with a bionic flow field and a fuel cell, and belongs to the technical field of fuel cells. The current collector comprises a current collector plate, a plurality of supporting bodies distributed at intervals are arranged on the mounting surface of the current collector plate, and every two adjacent supporting bodies are parallel to each other; the runner groove is defined by the opposite end surfaces and the mounting surfaces of any two adjacent supporting bodies; and the plurality of spirally rising bosses are arranged in the runner grooves, the lower surfaces of the bosses are parallel to the upper surfaces of the bosses, and the bosses are not in contact with the supporting bodies on the two sides. According to the invention, the spirally rising boss is mounted in the runner groove defined by the support body, so that substances in the fuel cell can be distributed more uniformly, retention of water in a flow field is reduced, pressure drop of an inlet and an outlet is reduced, and the output performance of the fuel cell is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and in particular to a fuel cell bipolar plate with a bionic flow field and a fuel cell comprising the fuel cell bipolar plate. Background Art

[0002] Proton exchange membrane fuel cells (PEMFCs) are one of the most efficient energy conversion devices for converting chemical energy into electrical energy. They can utilize the reaction of hydrogen and oxygen to produce water and electricity. They are environmentally friendly and have low working environment temperatures. They are considered to be one of the best choices for power systems in the transportation field.

[0003] The core components of PEMFCs are membrane electrode and bipolar plate. As an important place to support electrodes, conduct electrons, and transmit gas and water molecules, the flow field design of bipolar plate plays a key role in improving the specific power and specific energy of fuel cells. A reasonable flow field structure can effectively reduce the quality and cost of the battery, thereby improving the working performance of the fuel cell. Traditional flow fields mainly refer to parallel flow fields, serpentine flow fields, and interdigital flow fields. The invention patent with publication number CN115714186A discloses a flow field with variable cross-section serial parallel channels, but the parallel flow field has a simple structure and low inlet and outlet pressure drop, but is prone to flooding and uneven distribution of reactants; the invention patent with publication number CN116505011A discloses a multi-channel serpentine flow field bipolar plate, which has good performance and strong water removal ability, but high pressure drop and reduced net output power of the battery; the utility model patent with authorization announcement number CN202084601U discloses a proton exchange membrane fuel cell flow field structure including interdigitated flow field channels, which has high mass transfer efficiency and strong water removal ability, but high pressure drop and excessive gas flow rate that can easily damage the proton exchange membrane. Therefore, the design of the bipolar plate flow field structure needs to simultaneously balance performance indicators such as uniform distribution of reactants, rapid discharge of water generated by the reaction, and reasonable pressure drop. Compared with traditional flow fields, bionic flow fields can improve the performance of fuel cells without producing excessive pressure drop and causing little damage to the proton exchange membrane. Summary of the invention

[0004] In view of this, in order to solve the technical problems in the prior art such as prone to flooding and uneven distribution of reactants in fuel cell bipolar plates, on the one hand, the present invention provides a fuel cell bipolar plate with a bionic flow field, which can make the material distribution inside the fuel cell more uniform, reduce water retention in the flow field, reduce the inlet and outlet pressure drop, and help improve the output performance of the fuel cell by installing a spirally rising boss in the flow channel groove surrounded by the support body.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A fuel cell bipolar plate with a bionic flow field, comprising:

[0007] A current collector plate, on which a plurality of spaced-apart supports are provided, and two adjacent supports are parallel to each other;

[0008] A flow channel groove is formed by enclosing the opposite end faces of any two adjacent supports and the mounting surface;

[0009] A plurality of spirally rising bosses are arranged in the flow channel groove, the lower surface of the boss is parallel to the upper surface, and the boss does not contact the supports on both sides.

[0010] Preferably, the spiral angle formed by the first graphic symmetry line of the lower surface and the second graphic symmetry line of the upper surface is 0-90°.

[0011] Preferably, the height of the boss is 0.3-1.0 mm.

[0012] Preferably, the angles formed by the first graphic symmetry line of the lower surface and the side surfaces of the supports are all 0-90°.

[0013] Preferably, the boss is formed by spirally rising in the vertical direction with a basic graphic on the bottom surface;

[0014] The basic graphic is one of an ellipse, a circle and a rectangle.

[0015] Preferably, the basic graphic is an ellipse, the major axis of the ellipse is 0.4-0.8 mm, the minor axis is 0.2-0.4 mm, and the height of the boss is 0.3-1.0 mm.

[0016] Preferably, the basic graphic is a circle, the diameter of the circle is 0.3-0.8 mm, and the height of the boss is 0.7-1.0 mm.

[0017] Preferably, the basic graphic is a rectangle, the length of the rectangle is 0.2-0.8 mm, the width is 0.2-0.6 mm, and the height of the boss is 0.5-1.0 mm.

[0018] Preferably, the distance between adjacent supports is 0.8-1 mm.

[0019] On the other hand, the present invention also provides a fuel cell, including the fuel cell bipolar plate with the bionic flow field described above.

[0020] The present invention has the following beneficial effects compared with the prior art:

[0021] The fuel cell bipolar plate provided by the present invention has a unique bionic flow field design. This design ingeniously installs a helically rising boss structure inside the flow channel groove surrounded by the support body. This structure not only endows the bipolar plate with excellent gas permeability but also ensures the uniformity of the gas flow velocity inside the fuel cell. This uniform gas flow velocity is crucial for the uniformity of the internal material distribution and membrane current distribution in the fuel cell. In addition, this bionic flow field design also exhibits excellent water management performance, which can reduce the water retention phenomenon in the flow field to a certain extent, thereby reducing the inlet and outlet pressure drops. The reduction of this pressure drop has a significant positive impact on improving the output performance of the fuel cell, thus enhancing the overall performance of the fuel cell. Brief Description of the Drawings

[0022] Figure 1 It is a schematic structural diagram of the fuel cell bipolar plate of the present invention;

[0023] Figure 2 It is a top view of the flow channel groove;

[0024] Figure 3 It is a schematic structural diagram of a single helically rising boss;

[0025] Figure 4 It is a schematic diagram of the included angle between the upper and lower surface symmetry lines of the boss;

[0026] Figure 5 It is a partial enlarged view of the flow channel groove;

[0027] Figure 6 It is a schematic structural diagram of the cooperation with the support body;

[0028] Figure 7 It is a schematic diagram of the contact between the gas and the boss;

[0029] Figure 8 It is a schematic structural diagram with a circular basic shape;

[0030] Figure 9 It is a schematic structural diagram with a rectangular basic shape.

[0031] In the figure, 1. current collector plate; 2. boss; 3. support body; 11. lower surface; 12. upper surface; 13. side surface; 14. side surface of the other support body; 15. mounting surface; 16. inlet; 17. outlet; 18. flow channel groove; 19. boss side surface; 20. first figure symmetry line; 21. second figure symmetry line; 22. helix angle. Detailed Description of the Invention

[0032] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0033] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "inner", "outer", "top / bottom end", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0034] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "provided with", "sheathed / connected", "connected", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0035] As Figure 1-2 shown, the present invention provides a fuel cell bipolar plate with a bionic flow field, including:

[0036] A current collector plate 1, on whose mounting surface 15 there are provided a number of support bodies 3 distributed at intervals. These support bodies 3 are carefully designed to ensure that the adjacent two support bodies 3 are kept parallel to each other. This design not only helps to improve the overall stability of the current collector plate 1, but also can effectively disperse the pressure, thereby prolonging the service life of the current collector plate 1. Among the numerous surfaces of the current collector plate 1, the mounting surface 15 is preferably the one with a larger area. Such a choice helps the support bodies 3 to better play their functions. In addition, the connection mode between the support bodies 3 and the current collector plate 1 is also optimized to an integrally formed structure. This structure not only simplifies the manufacturing process, but also enhances the bonding strength between the support bodies 3 and the current collector plate 1, ensuring the firmness and reliability of the overall structure.

[0037] The current collector plate 1 and the support bodies 3 are preferably made of composite materials such as graphite with relatively strong structural strength. The size of the current collector plate 1 is preferably 50mm×10mm×0.3mm, and the size of the support bodies 3 is preferably 10mm×1mm×1mm.

[0038] The flow channel groove 18 is formed by the opposite end faces of any two adjacent support bodies 3 and the mounting surface 15 together. Specifically, the side surface 13 of these support bodies 3, the plane where the mounting surface 15 is located, and the side surface 14 of the other support body act together, and the length of the flow channel groove 18 is equal to the length of the support body 3. In this space, the water generated during the reaction can be effectively discharged from the bipolar plate of the fuel cell through the flow channel groove 18, and then further discharged outside the fuel cell. It should be noted that this flow channel groove 18 has two ports, serving as the inlet 16 and the outlet 17 respectively, so as to facilitate the flow and discharge of water.

[0039] A number of helically rising bosses 2 are arranged in the flow channel groove 18. The lower surface 11 of the boss 2 is parallel to the upper surface 12, and the boss 2 does not contact the two adjacent support bodies 3. Among them, the bosses 2 are distributed at least in one of linear equidistant distribution, staggered equidistant distribution, linear non-equidistant distribution and staggered non-equidistant distribution along the flow channel groove 18. The distribution spacing range along the first direction F1 in the same flow channel groove 18 is 1.0 - 5.0 mm, and the bosses 2 are spaced apart along the second direction F2 in the same flow channel groove 18, and the spacing range is 0 - 0.6 mm.

[0040] In the present invention, it is particularly pointed out that the structure of the boss 2 is formed by a structure with a basic figure as the bottom surface and extending upward in a spiral manner in the vertical direction;

[0041] Further elaborating, this basic figure can be any one of an ellipse, a circle or a rectangle, and these shapes provide different functions and aesthetic effects in design.

[0042] As Figure 3 shown, the boss 2 of the present invention is designed as a helically rising boss 2 through bionic analysis of the shape of a fish body. By setting the shape of the lower surface 11 and the spiral angle 22, the boss 2 is formed by spirally rising counterclockwise in the vertical direction with a basic figure as the bottom surface. Therefore, the contour of the boss 2 is determined by the cross-sectional shape of the lower surface 11.

[0043] As Figure 4 shown, in the present invention, the spiral angle 22 formed by the first figure symmetry line 20 of the lower surface 11 and the second figure symmetry line 21 of the upper surface 12 is 0 - 90°. As Figure 5 shown, the boss 2 does not contact the two adjacent support bodies 3. In the present invention, the height of the boss 2 is 0.3 - 1.0 mm. In the present invention, the angles formed by the first figure symmetry line 20 of the lower surface 11 and the side surface of the support body 3 are all 0 - 90°.

[0044] AsFigure 7 As shown in the figure, the fuel cell bipolar plate provided by the present invention has the design characteristics of a bionic flow field. This design not only significantly improves the flexibility and operability of the bipolar plate in the manufacturing process, but also ensures that during the operation of the fuel cell, gas can flow smoothly in the flow channels with higher efficiency. In addition, when the gas contacts the boss 2 structure during the flow process, a certain upward or downward component velocity will be generated. This design enables a part of the gas to more easily penetrate into the gas diffusion layer and then enter the catalyst layer more smoothly to participate in the chemical reaction. In this way, the working performance of the fuel cell is further improved, making the overall efficiency and performance of the battery more excellent.

[0045] As Figure 5 shown, a specific embodiment of the basic figure provided by the present invention is an ellipse. The optional range of the major axis of the ellipse is 0.4 - 0.8 mm, the minor axis range is 0.2 - 0.4 mm, and the height range of the boss 2 is 0.3 - 1.0 mm. Specifically as follows:

[0046] Example 1

[0047] The lower surface 11 of the boss 2 is parallel to the upper surface 12, and at the same time, the lower surface 11 is closely connected to the mounting surface 15, thus ensuring that the current collector plate 1, the support body 3, and the boss 2 can be effectively connected into a whole.

[0048] In this embodiment, the distance between the boss 2 and the inlet 16 is precisely set to 3.4 millimeters, and the boss 2 shows a symmetric layout relative to the support bodies 3 on both sides; in addition, the material used for the boss 2 is exactly the same as the materials selected for the current collector plate 1 and the support body 3.

[0049] As Figure 1 , Figure 2 and Figure 5 shown, a specific angle is formed between the first graphic symmetry line 20 of the lower surface 11 of the boss 2 and the side surface of the support body 3. According to the difference of this angle, the angle of contact between the boss 2 and the air flow will also change; by changing the angle when contacting the air flow, the rate of gas advancing forward and diffusing into the diffusion layer can be effectively controlled, and then it has an important impact on the process of the chemical reaction and the discharge of moisture.

[0050] In this embodiment, the range of the spiral angle 22 formed between the first graphic symmetry line 20 of the lower surface 11 of the boss 2 and the second graphic symmetry line 21 of the upper surface 12 is set between 0 - 90°. In addition, the angle formed between the first graphic symmetry line 20 of the lower surface 11 of the boss 2 and the gas flow direction, i.e., the first direction F1, is also within the range of 0 - 90°. Through such an angle design, a part of the gas can effectively obtain a faster downward speed, thereby entering the gas diffusion layer more smoothly. At the same time, the side surface 19 of the boss is designed as a relatively smooth curved surface, and this design draws on the characteristic that the body of a fish has less resistance to fluid when moving in water. Therefore, when the gas impacts the boss 2, compared with an ordinary curved surface, the energy loss of the gas will be significantly reduced. Such a design not only ensures the efficient progress of the mass transfer process but also effectively improves the current characteristics of the fuel cell. In addition, it also solves the problem of water accumulation in the battery generated during the operation of the battery, thereby ensuring the performance and lifespan of the battery.

[0051] In this specific embodiment, the angle formed between the first graphic symmetry line 20 and the side surface of the support 3 can be the same or different between different bosses 2, and both can improve the battery current characteristics and ensure the drainage function. In this specific embodiment, the angles formed between different bosses 2 and the side surface of the support 3 are all equal, that is, the angles formed between all the first graphic symmetry lines 20 and the side surface of the support 3 are 0 - 90°.

[0052] In this specific embodiment, by arranging a series of bosses 2 at fixed intervals in the flow channel groove 18, the wake area caused by a single boss 2 can be effectively reduced. This improvement in the design further reduces the energy loss of the gas and ensures the effective progress of the mass transfer process. At the same time, this structure also helps to make more gas enter the gas diffusion layer more easily, thereby significantly improving the overall performance of the battery.

[0053] In this embodiment, five bosses 2 with a spiral angle 22 of 6° and a height of 0.7 mm are evenly arranged at equal intervals in the first direction F1. The cross-section of the boss 2 is elliptical, with a major axis of the ellipse being 0.8 mm and a minor axis being 0.4 mm. The distance between adjacent bosses 2 is 3.4 mm, the distance between the first boss 2 and the inlet 16 is 3.4 mm, and the angle between the first graphic symmetry line 20 and the first direction F1 is 20°. Compared with the traditional straight channel, the maximum current density of the bionic flow field battery in this embodiment is increased by about 5.95%, the distribution of the electrolyte current density cloud map is uniform, and the average overall is increased by about 1.73%. The average gas velocity of the straight channel is 0.64 m / s, showing a trend of first slow and then fast overall, fluctuating in the range of 0.642 - 0.652 m / s; the velocity in this embodiment is basically stable at about 0.64 m / s, and the cloud map distribution is more uniform. The velocity increases near the boss 2, and the velocities at other parts inside the fuel cell tend to be the same.

[0054] As Figure 8 shown, the basic graphic is circular, the diameter of the circle is 0.3 - 0.8 mm, and the height of the boss 2 is 0.7 - 1.0 mm.

[0055] Embodiment 2

[0056] The bionic flow field bipolar plate in this embodiment is basically the same as the conditions in Embodiment 1. The difference is that the bottom contour of the boss 2 in the bionic flow field bipolar plate provided in this embodiment is circular, and the radius of the circle is 0.2 mm.

[0057] Compared with the traditional straight channel, the maximum current density of the bionic flow field battery in this embodiment is increased by about 7.8%, and the distribution of the electrolyte current density cloud map is uniform.

[0058] As Figure 9 shown, the basic graphic is rectangular, the length of the rectangle is 0.2 - 0.8 mm, the width is 0.2 - 0.6 mm, and the height of the boss 2 is 0.5 - 1.0 mm.

[0059] Embodiment 3

[0060] The bionic flow field bipolar plate in this embodiment is basically the same as the conditions in Embodiment 1. The difference is that the bottom contour of the boss 2 in the bionic flow field bipolar plate provided in this embodiment is rectangular, with a length of 0.6 mm and a width of 0.3 mm.

[0061] Compared with the traditional straight channel, the maximum current density of the bionic flow field battery in this embodiment is increased by about 9.1%.

[0062] As Figure 6 shown, in the present invention, the distance between adjacent supports 3 is 0.8 - 1 mm.

[0063] On the other hand, the present invention further provides a fuel cell with an innovative design, which specifically includes the above-mentioned fuel cell bipolar plate with a bionic flow field design. This unique design enables the fuel cell to significantly improve its overall performance when it is placed horizontally for use. It ensures that during the operation of the fuel cell, the gas in each part of each bipolar plate can be evenly distributed, thereby ensuring the uniformity of the distribution of fluid, pressure and concentration at various locations on the bipolar plate structure. In addition, this design can also effectively extend the service life of the fuel cell, allowing it to maintain stable and efficient performance during long-term operation.

[0064] The above is only a preferred specific implementation manner of the present invention; but the protection scope of the present invention is not limited thereto; any technician familiar with the technical field within the technical scope disclosed by the present invention; any equivalent replacement or change based on the technical solution and improved concept of the present invention shall be covered by the protection scope of the present invention.

Claims

1. A fuel cell bipolar plate with a biomimetic flow field, characterized in that, Comprising: A current collector plate, on whose mounting surface there are provided a plurality of support bodies distributed at intervals, and two adjacent said support bodies are parallel to each other; A flow channel groove formed by the opposite end faces of any two adjacent said support bodies and the mounting surface; A plurality of helically rising bosses provided in the flow channel groove, the lower surface of the boss being parallel to the upper surface, and the boss not contacting the support bodies on both sides.

2. The bipolar plate of a fuel cell with a bionic flow field according to claim 1, characterized in that, The helical angle formed by the first graphic symmetry line of the lower surface and the second graphic symmetry line of the upper surface is 0 - 90°.

3. The bipolar plate of a fuel cell with a bionic flow field according to claim 1, characterized in that, The height of the boss is 0.3 - 1.0 mm.

4. A fuel cell bipolar plate with a biomimetic flow field according to claim 1, characterized in that, The angles formed by the first graphic symmetry line of the lower surface and the side surfaces of the support bodies are all 0 - 90°.

5. The fuel cell bipolar plate with a biomimetic flow field according to claim 1, characterized in that The boss is formed by the spiral rise of a basic graphic in the vertical direction with the bottom surface; The basic graphic is one of an ellipse, a circle and a rectangle.

6. A fuel cell bipolar plate with a bionic flow field according to claim 5, characterized in that, The basic graphic is an ellipse, the major axis of the ellipse is 0.4 - 0.8 mm, the minor axis is 0.2 - 0.4 mm, and the height of the boss is 0.3 - 1.0 mm.

7. A fuel cell bipolar plate with a bionic flow field according to claim 5, characterized in that, The basic graphic is a circle, the diameter of the circle is 0.3 - 0.8 mm, and the height of the boss is 0.7 - 1.0 mm.

8. A fuel cell bipolar plate with a bionic flow field according to claim 5, characterized in that, The basic graphic is a rectangle, the length of the rectangle is 0.2 - 0.8 mm, the width is 0.2 - 0.6 mm, and the height of the boss is 0.5 - 1.0 mm.

9. A fuel cell bipolar plate with a bionic flow field according to any one of claims 1-8, characterized in that, The distance between adjacent said support bodies is 0.8 - 1 mm.

10. A fuel cell, characterized in that, A fuel cell bipolar plate with a bionic flow field, comprising any one of claims 1 - 9.

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