A fuel cell bipolar plate for enhancing fluid disturbance

Abstract

The present invention relates to a fuel cell bipolar plate for enhancing fluid disturbance, which comprises an anode plate (1) and a cathode plate (2). The anode plate (1) and the cathode plate (2) comprise a plurality of plate units (3). The plate unit (3) comprises a left ridge plate (311), a left side plate (321), a middle ridge plate (312), a right side plate (322) and a right ridge plate (313). Each ridge plate adopts a wavy curved surface structure, and there is a certain distance between the wave crests of the curved surfaces of two adjacent ridge plates. Each side plate connects two adjacent ridge plates and adopts a lofted curved surface structure. The two plates are installed back to back and in contact with each other. This bipolar plate structure can achieve the splitting and collision of fluids, generate forced convection perpendicular to the reaction plane, and significantly enhance the multi-directional disturbance of fluids. Compared with the prior art, the present invention can simultaneously strengthen the mass transfer characteristics of the anode and cathode flow fields and the heat transfer efficiency of the cooling flow field, thereby improving the output performance of the fuel cell, and this structure is suitable for mass production.

Description

Technical Field

[0001] The invention belongs to the technical field of fuel cells and relates to a fuel cell bipolar plate capable of enhancing fluid disturbance. Background Art

[0002] Hydrogen energy is gaining more and more attention as an environmentally friendly green energy. Proton exchange membrane fuel cell (PEMFC) is a power device that can directly convert hydrogen energy into electrical energy. It has outstanding advantages such as fast start-up in low temperature environment, low thermal radiation, low noise, low emission and high power density. It has broad application prospects in transportation, fixed power stations and aerospace. PEMFC is mainly composed of bipolar plate (BPP), membrane electrode assembly (MEA), sealing element and other components. As a key component of fuel cell, BPP not only has the functions of structural support and current conduction, but also the distributed flow field can promote the uniform distribution of reactants and coolant, and discharge the reaction products in time. It is an important place for fuel cell water and gas management. Therefore, the structural design of BPP is very critical.

[0003] With the continuous innovation of key technologies, the power density of PEMFC has made great progress, but there is still a lot of room for improvement before large-scale commercial application. A flow field with high disturbance characteristics can promote the material transfer, drainage and heat exchange of fuel cells, and can significantly improve the reaction uniformity and battery output performance, which is an important direction of BPP structural design.

[0004] After searching the existing technical literature, it was found that the Chinese invention patent CN109643809A discloses a meshing ultra-thin metal bipolar plate and its three-dimensional flow field. The invention enhances the fluid disturbance in the fuel cell by designing a flow channel structure with a trapezoidal cross-section and a wavy bottom surface, but the design still retains the traditional ridge groove structure, and the gas diffusion layer (GDL) under the ridge is compressed, so the improvement of the water vapor transmission performance of the entire flow field is limited. The Korean invention patent KR102034457B1 discloses a gas flow separator for a fuel cell. The invention effectively separates the gas and liquid flow areas by distributing multiple three-dimensional through-hole elements to avoid blockage of the reactant mass transfer path, and at the same time uses the through-hole elements to change the gas flow path to form a turbulent state that is conducive to drainage of the device. However, the invention does not have sealing properties and cannot be used alone as a plate for a fuel cell stack, and the production cost is relatively high. Chinese invention patent CN113823809A discloses a flow field structure of a fuel cell bipolar plate. The invention designs a "cross"-shaped boss array on the surface of each plate, and enhances the forced convection of the flow field through the mesh gas flow path formed between the bosses, thereby enhancing the mass transfer effect and heat exchange efficiency inside the fuel cell. However, the surface of the plate in the invention is a simple plane, and the cross-section of the gas flow path remains consistent, making it difficult to generate forced convection perpendicular to the reaction plane. In summary, although the disclosed fuel cell plate structure with high disturbance characteristics can enhance fluid disturbance to a certain extent, there are still many problems, including: lack of sealing, high production cost, and limited improvement of fluid disturbance, which further limits the practical application effect of the prior art. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and provide a fuel cell bipolar plate that enhances fluid disturbance. The present invention has good sealing performance, which can not only enhance fluid disturbance and improve the water vapor management performance of the fuel cell, but also facilitate manufacturing and assembly.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] A fuel cell bipolar plate for enhancing fluid disturbance comprises an anode plate and a cathode plate, wherein the anode plate and the cathode plate comprise a plurality of polar plate units, wherein the polar plate units comprise a left ridge plate, a left side plate, a middle ridge plate, a right side plate and a right ridge plate, wherein the left ridge plate, the middle ridge plate and the right ridge plate adopt a wavy curved surface structure, the left side plate connects the left ridge plate and the middle ridge plate, and the right side plate connects the right ridge plate and the middle ridge plate.

[0008] Furthermore, the wave crests of the structural curved surfaces of the left ridge plate and the right ridge plate are kept consistent, and are kept at a certain distance from the wave crests of the structural curved surface of the middle ridge plate.

[0009] Furthermore, the structural surfaces of the left ridge plate, the middle ridge plate and the right ridge plate are designed according to cosine function, sine function, Gaussian function or polynomial function.

[0010] As a preferred technical solution, the description function of the left ridge plate and the right ridge plate structural surface is f 1 The description function of the ridge plate structural surface is f 2 The crest distance between the left ridge plate and the right ridge plate structural curved surface and the middle ridge plate structural curved surface is L 1 There are many description functions for the two constructed surfaces. Take the cosine function as an example:

[0011] f 1 =0.5Acos(2πxL 2 -1 ), x∈[0,L 2 ]

[0012] f 2 =-0.5Acos(2πxL 2 -1 ), x∈[0,L 2 ]

[0013] Among them, A is the maximum height of the plate unit corresponding to the flow field, L 2 is the length of the plate unit.

[0014] The width of the left ridge plate is W 11 , the width of the left side plate is W 21 , the width of the ridge plate is W 12 , the width of the right side plate is W 22 , the width of the right ridge plate is W 13 The thickness of the left ridge plate, left side plate, middle ridge plate, right side plate and right ridge plate are all t.

[0015] As a preferred technical solution, the wave peak spacing between the left ridge plate and right ridge plate structural curved surface and the middle ridge plate structural curved surface, as well as the length and height of the plate unit can be adjusted according to requirements.

[0016] As a preferred technical solution, the width and thickness of the left spine plate, left side plate, middle spine plate, right side plate and right spine plate can be adjusted according to needs.

[0017] Furthermore, the left side plate and the right side plate adopt a lofted curved surface structure.

[0018] Furthermore, the left side plate is constructed by a lofted curved surface with the contours of the left ridge plate and the middle ridge plate as a guide path, and the right side plate is constructed by a lofted curved surface with the contours of the right ridge plate and the middle ridge plate as a guide path.

[0019] Furthermore, the guiding path of the left side plate structural surface can be set with a custom auxiliary constraint path based on the left ridge plate and the middle ridge plate contour (construction surface description function) as required, and the guiding path of the right side plate structural surface can be set with a custom auxiliary constraint path based on the right ridge plate and the middle ridge plate contour (construction surface description function) as required.

[0020] Furthermore, the anode plate and the cathode plate include a single plate unit arranged periodically or multiple plate units arranged in a mixed manner.

[0021] Furthermore, the anode plate and the cathode plate are installed back to back, fit together at the trough area of ​​the anode plate and the cathode plate, and are welded at the contact area of ​​the anode plate and the cathode plate to form an integrated bipolar plate structure.

[0022] As a preferred technical solution, the anode plate and cathode plate are both obtained by stamping metal alloy thin plates such as stainless steel or titanium alloy, and the integrated bipolar plate structure is obtained by laser welding or resistance spot welding.

[0023] As a preferred technical solution, the installation method of the anode plate and the cathode plate can be adjusted along the reaction plane direction according to design requirements such as the flow resistance of the cooling flow field, the contact resistance of the bipolar plate and the height of the bipolar plate.

[0024] Furthermore, the anode reactant flow areas in adjacent electrode plate units are interconnected, the cathode reactant flow areas are interconnected, and the coolant flow areas are interconnected.

[0025] Furthermore, the flow area on the upper surface of the anode plate forms the anode flow field of the bipolar plate, the flow area on the lower surface of the cathode plate forms the cathode flow field of the bipolar plate, and the flow area between the lower surface of the anode plate and the upper surface of the cathode plate forms the cooling flow field of the bipolar plate.

[0026] As a preferred technical solution, the flow direction of the cathode reactant in the bipolar plate is opposite to that of the anode reactant, and is perpendicular to the flow direction of the coolant.

[0027] As a preferred technical solution, hydrogen is selected as the cathode reactant in the bipolar plate, and air / oxygen is selected as the anode reactant.

[0028] Compared with the prior art, the present invention has the following advantages:

[0029] (1) The present invention can realize the diversion and collision of fluids and promote the generation of forced convection perpendicular to the reaction plane, significantly enhancing the multi-directional disturbance of the fluid, which is of great significance for improving the material transfer characteristics and heat exchange efficiency of the flow field;

[0030] (2) The present invention ensures the sealing of the electrode plate. By connecting the anode plate and the cathode plate back to back, an anode flow field, a cathode flow field and a cooling flow field with high disturbance characteristics can be formed. Compared with the prior art, the present invention saves materials and is more suitable for forming a high-power fuel cell stack.

[0031] (3) The present invention adopts smooth wavy curved surfaces and lofted curved surfaces for construction, has a simple structure, low processing difficulty, high yield rate, and can be mass-produced based on existing manufacturing processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Schematic diagram of the overall structure of the bipolar plate in Example 1 of the present invention;

[0033] Figure 2 This is a schematic diagram of the structure of the electrode plate unit in Example 1 of the present invention;

[0034] Figure 3 This is a schematic diagram of the front view structure of the bipolar plate in Example 1 of the present invention;

[0035] Figure 4 This is a schematic diagram of the left side structure of the bipolar plate in Example 1 of the present invention;

[0036] Figure 5 This is a schematic diagram of the front view structure of the electrode plate unit in Example 1 of the present invention;

[0037] Figure 6 This is a schematic diagram of the top view of the plate unit structure in Example 1 of the present invention;

[0038] Figure 7 This is a schematic diagram of the flow of anode reactants in Example 1 of the present invention;

[0039] Figure 8 This is a schematic diagram of the flow of cathode reactants in Example 1 of the present invention;

[0040] Fig. 9 This is a schematic diagram of the flow of the cooling liquid in Example 1 of the present invention;

[0041] Fig.10 A comparison diagram of oxygen content distribution in the catalyst layer of a fuel cell using the bipolar plate (a) in Example 1 of the present invention and a conventional bipolar plate (b);

[0042] Fig.11 A comparison diagram of the water content distribution of the GDL / BPP contact layer in a fuel cell using the bipolar plate (a) in Example 1 of the present invention and a conventional bipolar plate (b);

[0043] Fig.12 Schematic diagram of the overall structure of the bipolar plate in Example 2 of the present invention;

[0044] Fig.13This is a schematic diagram of the structure of the electrode plate unit in Example 2 of the present invention;

[0045] Fig.14 This is a schematic diagram of the front view structure of the bipolar plate in Example 2 of the present invention;

[0046] Fig.15 This is a schematic diagram of the left side structure of the bipolar plate in Example 2 of the present invention;

[0047] Fig.16 This is a schematic diagram of the front view structure of the electrode plate unit in Example 2 of the present invention;

[0048] Fig.17 Schematic diagram of the top view of the plate unit in Example 2 of the present invention.

[0049] Description of the markings in the figure:

[0050] 1—anode plate, 2—cathode plate, 3—plate unit, 311—left ridge plate, 312—middle ridge plate, 313—right ridge plate, 321—left side plate, 322—right side plate. DETAILED DESCRIPTION

[0051] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0052] Embodiment 1:

[0053] like Figures 1 to 4 As shown, a fuel cell bipolar plate for enhancing fluid disturbance includes an anode plate 1 and a cathode plate 2, wherein the anode plate 1 and the cathode plate 2 include a plurality of plate units 3, and the plate unit 3 includes a left ridge plate 311, a left side plate 321, a middle ridge plate 312, a right side plate 322 and a right ridge plate 313, the left ridge plate 311, the middle ridge plate 312 and the right ridge plate 313 adopt a wavy curved surface structure, the left side plate 321 realizes the connection between the left ridge plate 311 and the middle ridge plate 312, the right side plate 322 realizes the connection between the right ridge plate 313 and the middle ridge plate 312, and the left side plate 321 and the right side plate 322 adopt a lofted curved surface structure.

[0054] like Figure 2 and Figure 5 As shown, the description function of the construction surface of the left ridge plate 311 and the right ridge plate 313 is f 1 , the description function of the surface constructed by the ridge plate 312 is f 2 , the wave crest spacing between the left ridge plate 311 and the right ridge plate 313 and the middle ridge plate 312 is 2 mm, and the description functions of the two structural surfaces are as follows:

[0055] f 1=0.25cos(0.5πx), x∈[0, 4]

[0056] f 2 =-0.25cos(0.5πx), x∈[0, 4]

[0057] The maximum height of the plate unit 3 corresponding to the flow field is 0.5 mm, and the length of the plate unit 3 is 4 mm.

[0058] like Figure 2 As shown, the left side plate 321 is located between the left spine plate 311 and the middle spine plate 312, and is constructed by a lofted surface with the contours of the left spine plate 311 and the middle spine plate 312 as the guiding path. The right side plate 322 is located between the right spine plate 313 and the middle spine plate 312, and is constructed by a lofted surface with the contours of the right spine plate 313 and the middle spine plate 312 as the guiding path.

[0059] like Figure 6 As shown, the widths of the left ridge plate 311, the left side plate 321, the middle ridge plate 312, the right side plate 322 and the right ridge plate 313 in the plate unit 3 are 0.25 mm, 0.5 mm, 0.5 mm, 0.5 mm and 0.25 mm respectively, and the thickness of each part is 0.1 mm.

[0060] like Figure 1 As shown, the anode plate 1 and the cathode plate 2 include periodically arranged identical plate units 3, wherein the anode plate 1 and the cathode plate 2 are installed back to back, fit together in the trough area, and are laser welded to form an integrated bipolar plate structure.

[0061] like Figure 7 As shown, the flow area on the upper surface of the anode plate 1 forms the anode flow field of the bipolar plate, and the anode reactant flow areas in adjacent plate units 3 are interconnected.

[0062] like Figure 8 As shown, the flow area on the lower surface of the cathode plate 2 forms the cathode flow field of the bipolar plate, the cathode reactant flow areas in adjacent plate units 3 are interconnected, and the flow direction of the cathode reactant is opposite to that of the anode reactant.

[0063] like Fig. 9 As shown, the flow area between the lower surface of the anode plate 1 and the upper surface of the cathode plate 2 forms a cooling flow field of the bipolar plate, the coolant flow areas in adjacent plate units 3 are interconnected, and the flow direction of the coolant is perpendicular to the flow direction of the reactants.

[0064] The present embodiment with the same reaction area is compared with the conventional bipolar plate with parallel flow field, and simulation analysis is performed using ANSYS FLUENT software. Fig.10As shown, the distribution of oxygen (reactant) content in the catalyst layer of the fuel cell using the bipolar plate (a) described in this embodiment and the conventional bipolar plate (b) is compared. It can be found that: Fig.10 The oxygen mass fraction in (a) is significantly higher than Fig.10 (b) shows that this embodiment can provide more oxygen to the fuel cell and effectively improve the output performance of the fuel cell. Fig.10 The oxygen content of all nodes in the two cross sections (a) and (b) was statistically analyzed, and the results showed that the present embodiment can increase the average mass fraction of oxygen in the fuel cell catalyst layer by 11.32%. On the other hand, the distribution of water (product) content in the GDL / BPP contact layer in the fuel cell using the bipolar plate (a) described in the present embodiment and the conventional bipolar plate (b) was compared. The results are as follows: Fig.11 As shown. It can be found that Fig.11 (a) The quality fraction of reclaimed water is significantly lower than Fig.11 (b) shows that this embodiment can discharge the product water of the fuel cell more timely, reduce the blockage degree of the reactant transmission channel, reduce mass transfer polarization, and achieve higher performance output of the fuel cell. Fig.11 The water content of all nodes in the two sections (a) and (b) was statistically analyzed. The results showed that this embodiment can reduce the average mass fraction of product water in the GDL / BPP contact layer by 7.42%. Fig.10 and Fig.11 From the distribution pattern of oxygen and water in the fuel cell, it can be found that this embodiment also improves the distribution uniformity of reactants and products, which helps to improve the stability of fuel cell operation.

[0065] Embodiment 2:

[0066] like Figures 12 to 15 As shown, a fuel cell bipolar plate for enhancing fluid disturbance includes an anode plate 1 and a cathode plate 2, wherein the anode plate 1 and the cathode plate 2 include a plurality of plate units 3, and the plate unit 3 includes a left ridge plate 311, a left side plate 321, a middle ridge plate 312, a right side plate 322 and a right ridge plate 313, the left ridge plate 311, the middle ridge plate 312 and the right ridge plate 313 adopt a wavy curved surface structure, the left side plate 321 realizes the connection between the left ridge plate 311 and the middle ridge plate 312, the right side plate 322 realizes the connection between the right ridge plate 313 and the middle ridge plate 312, and the left side plate 321 and the right side plate 322 adopt a lofted curved surface structure.

[0067] like Fig.13 and Fig.16 As shown, the description function of the construction surface of the left ridge plate 311 and the right ridge plate 313 is f 1 , the description function of the surface constructed by the ridge plate 312 is f 2The crest distance between the left ridge plate 311 and the right ridge plate 313 and the middle ridge plate 312 is 4 mm. The description functions of the two structural surfaces are as follows:

[0068] f 1 =-0.25cos(0.25πx), x∈[0, 8]

[0069] f 2 =0.25cos(0.25πx), x∈[0, 8]

[0070] The maximum height of the plate unit 3 corresponding to the flow field is 0.5 mm, and the length of the plate unit 3 is 8 mm.

[0071] like Fig.13 As shown, the left side plate 321 is located between the left spine plate 311 and the middle spine plate 312, and is constructed by a lofted surface with the contours of the left spine plate 311 and the middle spine plate 312 as the guiding path. The right side plate 322 is located between the right spine plate 313 and the middle spine plate 312, and is constructed by a lofted surface with the contours of the right spine plate 313 and the middle spine plate 312 as the guiding path.

[0072] like Fig.17 As shown, the widths of the left ridge plate 311, the left side plate 321, the middle ridge plate 312, the right side plate 322 and the right ridge plate 313 in the plate unit 3 are 0.25 mm, 0.5 mm, 0.5 mm, 0.5 mm and 0.25 mm respectively, and the thickness of each part is 0.1 mm.

[0073] The installation method of the anode plate 1 and the cathode plate 2, the formation method of the anode flow field, the cathode flow field and the cooling flow field, and the corresponding fluid flow method in Example 2 are consistent with those in Example 1, and therefore will not be repeated.

[0074] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A fuel cell bipolar plate for enhancing fluid disturbance, comprising an anode plate (1) and a cathode plate (2), characterized in that, the anode plate (1) and the cathode plate (2) comprise a plurality of plate units (3), and the plate unit (3) comprises a left ridge plate (311), a left side plate (321), a middle ridge plate (312), a right side plate (322) and a right ridge plate (313). The left ridge plate (311), the middle ridge plate (312) and the right ridge plate (313) adopt a wavy curved surface structure. The left side plate (321) connects the left ridge plate (311) and the middle ridge plate (312), and the right side plate (322) connects the right ridge plate (313) and the middle ridge plate (312); the wave crests of the curved surfaces of the left ridge plate (311) and the right ridge plate (313) are consistent and maintain a certain distance from the wave crest of the curved surface of the middle ridge plate (312); the anode plate (1) and the cathode plate (2) comprise a single plate unit (3) arranged periodically or a plurality of plate units (3) arranged in a mixed manner; the anode plate (1) and the cathode plate (2) are attached and installed back to back, and are attached in the trough areas of the anode plate (1) and the cathode plate (2), and are welded in the contact areas of the anode plate (1) and the cathode plate (2) to form an integrated bipolar plate structure.

2. A fuel cell bipolar plate for enhancing fluid disturbance according to claim 1, characterized in that, the curved surfaces of the left ridge plate (311), the middle ridge plate (312) and the right ridge plate (313) are designed according to a cosine function, a sine function, a Gaussian function or a polynomial function.

3. A fuel cell bipolar plate for enhancing fluid disturbance according to claim 1, characterized in that, the left side plate (321) and the right side plate (322) adopt a lofted surface structure.

4. A fuel cell bipolar plate for enhancing fluid disturbance according to claim 3, characterized in that, the left side plate (321) is constructed by a lofted surface with the contours of the left ridge plate (311) and the middle ridge plate (312) as the guiding paths, and the right side plate (322) is constructed by a lofted surface with the contours of the right ridge plate (313) and the middle ridge plate (312) as the guiding paths.

5. A fuel cell bipolar plate for enhancing fluid disturbance according to claim 4, characterized in that, the guiding path of the curved surface of the left side plate (321) is provided with an auxiliary constraint path on the basis of the contours of the left ridge plate (311) and the middle ridge plate (312), and the guiding path of the curved surface of the right side plate (322) is provided with an auxiliary constraint path on the basis of the contours of the right ridge plate (313) and the middle ridge plate (312).

6. A fuel cell bipolar plate for enhancing fluid disturbance according to claim 1, characterized in that, the anode reactant flow regions in adjacent plate units (3) communicate with each other, the cathode reactant flow regions communicate with each other, and the coolant flow regions communicate with each other.

7. A fuel cell bipolar plate for enhancing fluid disturbance according to claim 1, characterized in that, The flow-through area on the upper surface of the anode plate (1) forms the anode flow field of the bipolar plate, the flow-through area on the lower surface of the cathode plate (2) forms the cathode flow field of the bipolar plate, and the flow-through area between the lower surface of the anode plate (1) and the upper surface of the cathode plate (2) forms the cooling flow field of the bipolar plate.

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