A porous metal flow field plate for fuel cells that enhances gas uniformity and drainage

Abstract

The present invention discloses a fuel cell porous metal flow field plate for enhancing gas uniformity and drainage performance, which relates to the technical field of fuel cells. It includes a conductive separator and porous metal. A groove is provided in the middle part of the conductive separator, and the porous metal is arranged in the groove. One end of the conductive separator is provided with a fuel inlet, an oxidant inlet and a coolant inlet, and the other end is provided with a fuel outlet, an oxidant outlet and a coolant outlet. The number of the fuel inlet, the oxidant inlet, the fuel outlet and the oxidant outlet is at least two. Flow guiding areas are provided between the fuel inlet, the oxidant inlet, the coolant inlet, the fuel outlet, the oxidant outlet and the coolant outlet and the porous metal. By setting multiple reaction gas inlets and outlets, the interaction of multiple airflows effectively avoids the occurrence of airflow blind areas at the diagonal positions of the flow field other than the gas inlets and outlets, prevents the accumulation of liquid water in the airflow blind areas, improves the drainage performance, reduces the pressure drop, and ensures the performance of the fuel cell.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and particularly relates to a porous metal flow field plate for a fuel cell that enhances gas uniformity and drainage performance. Background Art

[0002] A fuel cell is a power generation device that converts the chemical energy in fuel and oxidant into electrical energy through an electrochemical reaction. Its key components include a membrane electrode assembly, a gas diffusion layer, a flow field plate, a current collector plate, and a gasket. Among them, the flow field plate accounts for about 60% - 80% of the volume and weight of the fuel cell, and the cost accounts for 20% - 40%. The function of the flow field plate in a fuel cell is to evenly distribute fuel gas and oxidant, collect and conduct current, discharge reaction products and heat, support the membrane electrode assembly to maintain the stability of the stack structure, etc. Therefore, the flow field plate material should have good electrical conductivity, thermal conductivity, and corrosion resistance, have a certain mechanical strength, and at the same time be able to guide the flow of reaction gases and product water.

[0003] Common flow field plates have flow channels with a groove-ridge structure. Due to limitations in structure and processing methods, the power density of fuel cells improved by such flow field plates is limited. Porous metal as a flow field plate can enhance mass transfer and has the characteristic of improving the uniformity of the distribution of reaction gases and coolant, thus promising to further improve the performance of fuel cells and meet the requirements of future high-power density fuel cells. However, due to the lack of guidance from fixed flow channels, the gas distribution in the porous metal flow field plate may still be uneven in some areas, especially in areas far from the gas inlet and outlet of the flow field plate. At the same time, since the gas velocity in these areas is low, the generated liquid water is not easily discharged and will accumulate in the pores, deteriorating the performance of the fuel cell. The pressure drop of the reaction gas in the porous metal flow field is also large, which will increase the energy loss of the air compressor.

[0004] The invention patent "Electrode Separator Structure and Fuel Cell Using the Same" with the publication number CN111384412A proposes an electrode separator structure, including a conductive gas-blocking layer and a conductive porous structure. The conductive porous structure is at least three layers of hole layers stacked by a plurality of holes with the same shape, which can improve the oxygen exchange rate of the cathode. The disadvantage of this structure is that the gas flow resistance in the flow field is uneven, gas short-circuit is likely to occur, resulting in difficult drainage. At the same time, this structure is relatively complex, and the design and processing are difficult.

[0005] The invention patent "Foam Metal Flow Field Plate and Fuel Cell Comprising the Same" with the bulletin number CN109193005B uses three different hydrophobic foam metals to form the fuel cell flow field plate, which can play a certain role in promoting the flow of liquid water. However, the capillary pressure is generally small. By adjusting the contact angle of the foam metal in different regions and using capillary pressure to drive liquid water, it is difficult to effectively discharge the liquid water in the flow field.

[0006] The invention patent "A porous flow field fuel cell monomer and series-parallel stack structure without bipolar plates" with the publication number CN113346101A includes an anode porous layer, an anode gas diffusion layer, a membrane electrode, a cathode gas diffusion layer, a cathode porous layer, a cathode baffle, a cooling porous layer, and an anode baffle. By reasonably designing the structure, porosity, and permeability, the flow resistance of the porous flow field can be effectively reduced, and the fluid distribution uniformity can be improved. However, whether it is an open flow channel or a non-uniform arrangement of porosity and permeability mentioned in this patent, there are great difficulties in design and processing, and it will also increase the contact resistance between the porous material and other components, reducing the battery performance.

[0007] The existing fuel cell flow field plates mainly have the following problems: For the flow field plate with a groove-ridge structure, since the reaction gas only flows in the grooves, the distribution of the reaction gas in the membrane electrode under the grooves and under the ridges is uneven; the reaction gas in the porous material flow field plate is prone to short-circuiting. Especially in the area far from the gas inlet and outlet, the gas concentration is low, the gas flow rate is small, and the generated liquid water is also difficult to discharge. As Figure 1 shown in the porous material flow field plate, generally, the gas inlets A and B are arranged diagonally. The reaction gas enters the flow field E from the inlet A and flows out from the outlet B. In the diagonal regions C and D of the flow field plate that are not gas inlets and outlets, there are easily gas flow blind spots. The gas flow velocity in this area is very small, resulting in difficulty in discharging liquid water, which will block the pores of the porous material and reduce the performance of the fuel cell. Summary of the Invention

[0008] The main purpose of the present invention is to provide a porous metal flow field plate for a fuel cell that enhances gas uniformity and drainage to solve the problems existing in the prior art.

[0009] To solve the above technical problems, the present invention adopts the following technical solutions:

[0010] A porous metal flow field plate for a fuel cell that enhances gas uniformity and drainage, including a conductive separator and porous metal. A groove is provided in the middle part of the conductive separator, and the porous metal is arranged in the groove;

[0011] One end of the conductive separator is provided with a fuel inlet, an oxidant inlet, and a coolant inlet, and the other end is provided with a fuel outlet, an oxidant outlet, and a coolant outlet. The number of the fuel inlet, the oxidant inlet, the fuel outlet, and the oxidant outlet is at least two. A flow guiding area is provided between the fuel inlet, the oxidant inlet, the coolant inlet, the fuel outlet, the oxidant outlet, and the coolant outlet and the porous metal.

[0012] Further, the conductive separator is a metal separator, and the shape of the porous metal is rectangular;

[0013] The number of the fuel inlets is two, namely a first anode inlet and a second anode inlet. The first anode inlet and the second anode inlet are located at the upper part of the metal separator and are symmetrically distributed along the axis of the porous metal. The number of the coolant inlets is one, namely a first coolant inlet. The first coolant inlet is located at the middle position of the top of the metal separator. The number of the oxidant inlets is two, namely a first cathode inlet and a second cathode inlet. The first cathode inlet and the second cathode inlet are symmetrically distributed along the first coolant inlet;

[0014] The number of the fuel outlets is two, namely a first anode outlet and a second anode outlet. The first anode outlet and the second anode outlet are located at the lower part of the metal separator and are symmetrically distributed along the axis of the porous metal. The number of the coolant outlets is one, namely a first coolant outlet. The first coolant outlet is located at the middle position of the bottom of the metal separator. The number of the oxidant outlets is two, namely a first cathode outlet and a second cathode outlet. The first cathode outlet and the second cathode outlet are symmetrically distributed along the first coolant outlet.

[0015] Furthermore, the flow guiding area includes a first anode inlet flow guiding area corresponding to the first anode inlet, a second anode inlet flow guiding area corresponding to the second anode inlet, a first cathode inlet flow guiding area corresponding to the first cathode inlet, a second cathode inlet flow guiding area corresponding to the second cathode inlet, a first coolant inlet flow guiding area corresponding to the first coolant inlet, a first anode outlet flow guiding area corresponding to the first anode outlet, a second anode outlet flow guiding area corresponding to the second anode outlet, a first cathode outlet flow guiding area corresponding to the first cathode outlet, a second cathode outlet flow guiding area corresponding to the second cathode outlet, and a first coolant outlet flow guiding area corresponding to the first coolant outlet.

[0016] Furthermore, the first anode inlet flow guiding area, the second anode inlet flow guiding area, the first anode outlet flow guiding area, the second anode outlet flow guiding area, the first coolant inlet flow guiding area, and the first coolant outlet flow guiding area are all groove structures. The first cathode inlet flow guiding area, the second cathode inlet flow guiding area, the first cathode outlet flow guiding area, and the second cathode outlet flow guiding area are all circular convex structures distributed in a dot matrix.

[0017] Furthermore, the conductive separator is a graphite separator, and the shapes of the graphite separator and the porous metal are both circular;

[0018] The numbers of the fuel inlets, oxidant inlets, coolant inlets, fuel outlets, oxidant outlets, and coolant outlets are all two;

[0019] The fuel inlets include a third anode inlet and a fourth anode inlet, which are arranged along the circumference of the graphite separator, and the third anode inlet and the fourth anode inlet are symmetrically distributed around the center of the porous metal;

[0020] The oxidant inlets include a third cathode inlet and a fourth cathode inlet, which are arranged along the circumference of the graphite separator, and the third cathode inlet and the fourth cathode inlet are symmetrically distributed around the center of the porous metal;

[0021] The coolant inlets include a second coolant inlet and a third coolant inlet, which are arranged along the circumference of the graphite separator, and the second coolant inlet and the third coolant inlet are symmetrically distributed around the center of the porous metal;

[0022] The fuel outlets include a third anode outlet and a fourth anode outlet, which are arranged along the circumference of the graphite separator, and the third anode outlet and the fourth anode outlet are symmetrically distributed around the center of the porous metal;

[0023] The oxidant outlets include a third cathode outlet and a fourth cathode outlet, which are arranged along the circumference of the graphite separator, and the third cathode outlet and the fourth cathode outlet are symmetrically distributed around the center of the porous metal;

[0024] The coolant outlets include a second coolant outlet and a third coolant outlet, which are arranged along the circumference of the graphite separator, and the second coolant outlet and the third coolant outlet are symmetrically distributed around the center of the porous metal.

[0025] Furthermore, the flow guiding area includes a third anode inlet flow guiding area corresponding to the third anode inlet, a fourth anode inlet flow guiding area corresponding to the fourth anode inlet, a third cathode inlet flow guiding area corresponding to the third cathode inlet, a fourth cathode inlet flow guiding area corresponding to the fourth cathode inlet, a second coolant inlet flow guiding area corresponding to the second coolant inlet, a third coolant inlet flow guiding area corresponding to the third coolant inlet, a third anode outlet flow guiding area corresponding to the third anode outlet, a fourth anode outlet flow guiding area corresponding to the fourth anode outlet, a third cathode outlet flow guiding area corresponding to the third cathode outlet, a fourth cathode outlet flow guiding area corresponding to the fourth cathode outlet, a second coolant outlet flow guiding area corresponding to the second coolant outlet, and a third coolant outlet flow guiding area corresponding to the third coolant outlet.

[0026] Further, the third anode inlet flow guiding area, the fourth anode inlet flow guiding area, the third anode outlet flow guiding area, the fourth anode outlet flow guiding area, the second coolant inlet flow guiding area, the second coolant outlet flow guiding area, the third coolant inlet flow guiding area, and the third coolant outlet flow guiding area are all groove structures, and the third cathode inlet flow guiding area, the fourth cathode inlet flow guiding area, the third cathode outlet flow guiding area, and the fourth cathode outlet flow guiding area are all circular convex structures distributed in a dot matrix.

[0027] Further, the porous metal includes at least two kinds of porous metals with different porosities and pore diameters. The porous metal with a smaller porosity and pore diameter is arranged in the area with a larger gas flow velocity in the flow field, and the porous metal with a larger porosity and pore diameter is arranged in the area with a smaller gas flow velocity in the flow field.

[0028] Further, the porosity of the porous metal is 70% - 95%, and the pore diameter is 60μm - 400μm.

[0029] Further, a sealing groove is provided on the conductive separator, and a sealing ring is provided in the sealing groove.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] By providing multiple reaction gas inlets and outlets, and the interaction of multiple airflows, compared with the common porous flow field with diagonal arrangement of reaction gas inlets and outlets, it can effectively avoid the airflow blind area at the diagonal position of the non-gas inlet and outlet in the flow field, avoid the accumulation of liquid water in the airflow blind area, effectively improve the drainage performance, and reduce the pressure drop;

[0032] According to the different gas flow velocities in different regions, porous metals with different porosities and pore diameters are used as the flow field, which further improves the uniformity of gas distribution in the flow field, enhances the drainage performance at the same time, and the porous metal has a simple shape and is convenient to process. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a diagram of the structure of a conventional porous metal flow field plate and the fluid flow path.

[0034] Figure 2 It is a cross-sectional view of Embodiment 1 of the present invention.

[0035] Figure 3 It is a schematic diagram of the structure of Embodiment 1 of the present invention when using three kinds of porous metals with different pore diameters and porosities.

[0036] Figure 4 It is a cross-sectional view of Embodiment 2 of the present invention.

[0037] Figure 5 It is a schematic diagram of the structure of Embodiment 2 of the present invention when using three kinds of porous metals with different pore diameters and porosities.

[0038] Among them, the metal separator 1, rectangular porous metal 2, first anode inlet 3, second anode inlet 4, first cathode inlet 5, second cathode inlet 6, first coolant inlet 7, first anode inlet diversion area 8, second anode inlet diversion area 9, first cathode inlet diversion area 10, second cathode inlet diversion area 11, first coolant inlet diversion area 12, first anode outlet 13, second anode outlet 14, first cathode outlet 15, second cathode outlet 16, first coolant outlet 17, first anode outlet diversion area 18, second anode outlet diversion area 19, first cathode outlet diversion area 20, second cathode outlet diversion area 21, first coolant outlet diversion area 22, first sealing groove 23, first rectangular porous metal 24, second rectangular porous metal 25, third rectangular porous metal 26;

[0039] The graphite separator 27, circular porous metal 28, third anode inlet 29, fourth anode inlet 30, third anode outlet 31, fourth anode outlet 32, third cathode inlet 33, fourth cathode inlet 34, third cathode outlet 35, fourth cathode outlet 36, second coolant outlet 37, third coolant outlet 38, second coolant inlet 39, third coolant inlet 40, third anode inlet diversion area 41, fourth anode inlet diversion area 42, fourth anode outlet diversion area 43, third anode outlet diversion area 44, third cathode inlet diversion area 45, fourth cathode inlet diversion area 46, third cathode outlet diversion area 47, fourth cathode outlet diversion area 48, third coolant inlet diversion area 49, second coolant inlet diversion area 50, third coolant outlet diversion area 51, second coolant outlet diversion area 52, second sealing groove 53, first circular porous metal 54, second circular porous metal 55, third circular porous metal 56. Specific implementation manners

[0040] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0041] Embodiment 1

[0042] Combined with Figures 2 to 3 , the present invention provides a fuel cell porous metal flow field plate for enhancing gas uniformity and drainage, including a conductive separator and a porous metal. A groove is provided in the middle part of the conductive separator, and the porous metal is disposed in the groove;

[0043] One end of the conductive separator is provided with a fuel inlet, an oxidant inlet and a coolant inlet, and the other end is provided with a fuel outlet, an oxidant outlet and a coolant outlet. The number of the fuel inlet, the oxidant inlet, the fuel outlet and the oxidant outlet is at least two. Flow guiding areas are arranged between the fuel inlet, the oxidant inlet, the coolant inlet, the fuel outlet, the oxidant outlet and the porous metal. The flow guiding areas are in a groove structure or a lattice protrusion structure.

[0044] In this embodiment, the porous metal flow field is adopted to alleviate the problem of uneven distribution of reaction gases in the membrane electrode of the grooved ridge structure flow field. Specifically, two fuel inlets, two fuel outlets, two oxidant inlets and two oxidant outlets are arranged, which can increase the coverage range of the reaction gas inlets and outlets. The interaction of multiple airflows can eliminate the airflow blind areas in the porous metal flow field, improve the uniformity of the airflow velocity distribution, enhance the drainage capacity of the flow field, and at the same time reduce the flow field pressure drop and the energy consumption of the air compressor.

[0045] The material of the conductive separator can be metals such as stainless steel, titanium, aluminum, copper, etc., or graphite. Stainless steel, titanium and graphite are preferred; the material of the porous metal can be foam metals such as nickel foam, copper foam, titanium foam, aluminum foam, etc., or metal fiber sintered felts such as titanium fiber felt, stainless steel fiber felt, iron-chromium-aluminum fiber felt. The conductive separator and the porous metal are preferably surface-treated to prepare a conductive and corrosion-resistant coating on their surfaces to meet the use requirements of the fuel cell under acidic working conditions.

[0046] Preferably, the porosity of the porous metal is 70% - 95%, and the pore diameter is 60μm - 400μm. The shape can be rectangular, circular or annular. The porous metal includes at least two kinds of porous metals with different porosities and pore diameters. The porous metal with a smaller porosity and pore diameter is arranged in the area with a larger gas flow velocity in the flow field, and the porous metal with a larger porosity and pore diameter is arranged in the area with a smaller gas flow velocity in the flow field, which can further increase the uniformity of the airflow velocity distribution. In another embodiment, the porous metal can also only adopt one kind of porous metal, that is, the porosity and pore diameter of the whole porous metal are the same.

[0047] Preferably, a sealing groove is arranged on the conductive separator, and a sealing ring is arranged in the sealing groove. After the battery is assembled, the sealing ring in the sealing groove can seal the periphery of the reaction gas and coolant inlets and outlets. In this embodiment, the sealing groove is the first sealing groove 23.

[0048] Preferably, in this embodiment, the conductive separator is the metal separator 1, the material is stainless steel, the shape of the porous metal is rectangular, and the material is stainless steel fiber felt, that is, the porous metal is the rectangular porous metal 2.

[0049] The number of the fuel inlets is two, namely a first anode inlet 3 and a second anode inlet 4. The first anode inlet 3 and the second anode inlet 4 are located at the upper part of the metal separator 1 and are symmetrically distributed along the axis of the porous metal. The number of the coolant inlets is one, namely a first coolant inlet 7. The first coolant inlet 7 is located at the middle position of the top of the metal separator 1. The number of the oxidant inlets is two, namely a first cathode inlet 5 and a second cathode inlet 6. The first cathode inlet 5 and the second cathode inlet 6 are symmetrically distributed along the first coolant inlet 7;

[0050] The number of the fuel outlets is two, namely a first anode outlet 13 and a second anode outlet 14. The first anode outlet 13 and the second anode outlet 14 are located at the lower part of the metal separator 1 and are symmetrically distributed along the axis of the porous metal. The number of the coolant outlets is one, namely a first coolant outlet 17. The first coolant outlet 17 is located at the middle position of the bottom of the metal separator 1. The number of the oxidant outlets is two, namely a first cathode outlet 15 and a second cathode outlet 16. The first cathode outlet 15 and the second cathode outlet 16 are symmetrically distributed along the first coolant outlet 17.

[0051] The diversion area includes a first anode inlet diversion area 8 corresponding to the first anode inlet 3, a second anode inlet diversion area 9 corresponding to the second anode inlet 4, a first cathode inlet diversion area 10 corresponding to the first cathode inlet 5, a second cathode inlet diversion area 11 corresponding to the second cathode inlet 6, a first coolant inlet diversion area 12 corresponding to the first coolant inlet, a first anode outlet diversion area 18 corresponding to the first anode outlet 13, a second anode outlet diversion area 19 corresponding to the second anode outlet 14, a first cathode outlet diversion area 20 corresponding to the first cathode outlet 15, a second cathode outlet diversion area 21 corresponding to the second cathode outlet 16, and a first coolant outlet diversion area 22 corresponding to the first coolant outlet 17.

[0052] In this embodiment, the first anode inlet diversion area 8, the second anode inlet diversion area 9, the first anode outlet diversion area 18, the second anode outlet diversion area 19, the first coolant inlet diversion area 12, and the first coolant outlet diversion area 22 are all groove structures, and the first cathode inlet diversion area 10, the second cathode inlet diversion area 11, the first cathode outlet diversion area 20, and the second cathode outlet diversion area 21 are all circular convex structures distributed in a dot matrix.

[0053] The metal separator 1 of this embodiment is formed by stamping with a corresponding mold. The stamped metal separator 1 includes: an anode inlet and outlet, a cathode inlet and outlet, a coolant inlet and outlet, grooves, an anode inlet and outlet diversion area, a cathode inlet and outlet diversion area, a coolant inlet and outlet diversion area, a sealing groove, etc. Subsequently, the porous metal is installed in the grooves. After the two stamped metal separators 1 are aligned at their respective corresponding positions and welded back to back, a porous metal flow field plate can be obtained.

[0054] When the porous metal flow field plate is made and used, the first coolant inlet diversion area 12 and the first coolant outlet diversion area 22 form a coolant channel, thereby diverting and distributing the cooling water, so that the cooling water evenly flows through the cooling water flow field and evenly takes away the heat generated during the operation of the battery; the gases introduced into the cathode inlet and outlet and the anode inlet and outlet are fuel gas and oxidant gas respectively. The first anode inlet diversion area 8, the second anode inlet diversion area 9, the first anode outlet diversion area 18, the second anode outlet diversion area 19, the first cathode inlet diversion area 10, the second cathode inlet diversion area 11, the first cathode outlet diversion area 20 and the second cathode outlet diversion area 21 divert the reaction gases, so that the gases enter evenly and are distributed into the flow field. It is not necessary to process flow channels in the flow field to achieve the uniform distribution of reaction gases and coolant. The processing is simple and the cost is low, and there is a possibility of large-scale application.

[0055] At the same time, the cathode inlet and outlet and the anode inlet and outlet that are symmetrically distributed left and right rather than only arranged diagonally in the flow field can shorten the flow path of the gas in the flow field, increase the gas flow velocity at the edge position of the flow field, enhance the drainage capacity of the porous metal flow field, and at the same time make the electrochemical reaction more uniform.

[0056] In order to further improve the uniformity of gas distribution in the flow field and at the same time enhance the drainage performance, the porosity and pore diameter of the porous metal in the entire flow field area can vary according to the gas flow velocity. As Figure 3 shown, the porous metal flow field is composed of three kinds of porous metals with different pore diameters, porosities and thus different permeabilities, namely the first rectangular porous metal 24, the second rectangular porous metal 25, and the third rectangular porous metal 26. Since the fluid flow velocity at the edge position of the flow field is relatively large and the fluid flow velocity in the middle area of the flow field is small, the permeabilities of the first rectangular porous metal 24, the second rectangular porous metal 25, and the third rectangular porous metal 26 increase in turn. The shapes of the three kinds of porous metals are rectangular or rectangular rings, and the processing is simple.

[0057] Embodiment 2

[0058] Combined with Figures 4 to 5, this embodiment provides a fuel cell porous metal flow field plate with another structure for enhancing gas uniformity and drainage. The difference between this embodiment and Embodiment 1 is that the conductive separator is a graphite separator 27, that is, the material of the conductive separator is graphite, and the material of the porous metal is nickel foam, and the shape is circular, that is, the porous metal is a circular porous metal 28.

[0059] The numbers of the fuel inlet, oxidant inlet, coolant inlet, fuel outlet, oxidant outlet, and coolant outlet are all two;

[0060] The fuel inlet includes a third anode inlet 29 and a fourth anode inlet 30. The third anode inlet 29 and the fourth anode inlet 30 are arranged along the circumference of the graphite separator 27, and the third anode inlet 29 and the fourth anode inlet 30 are symmetrically distributed along the center of the porous metal;

[0061] The oxidant inlet includes a third cathode inlet 33 and a fourth cathode inlet 34. The third cathode inlet 33 and the fourth cathode inlet 34 are arranged along the circumference of the graphite separator 27, and the third cathode inlet 33 and the fourth cathode inlet 34 are symmetrically distributed along the center of the porous metal;

[0062] The coolant inlet includes a second coolant inlet 39 and a third coolant inlet 40. The second coolant inlet 39 and the third coolant inlet 40 are arranged along the circumference of the graphite separator 27, and the second coolant inlet 39 and the third coolant inlet 40 are symmetrically distributed along the center of the porous metal;

[0063] The fuel outlet includes a third anode outlet 31 and a fourth anode outlet 32. The third anode outlet 31 and the fourth anode outlet 32 are arranged along the circumference of the graphite separator 27, and the third anode outlet 31 and the fourth anode outlet 32 are symmetrically distributed along the center of the porous metal;

[0064] The oxidant outlet includes a third cathode outlet 35 and a fourth cathode outlet 36. The third cathode outlet 35 and the fourth cathode outlet 36 are arranged along the circumference of the graphite separator 27, and the third cathode outlet 35 and the fourth cathode outlet 36 are symmetrically distributed along the center of the porous metal;

[0065] The coolant outlet includes a second coolant outlet 37 and a third coolant outlet 38. The second coolant outlet 37 and the third coolant outlet 38 are arranged along the circumference of the graphite separator 27, and the second coolant outlet 37 and the third coolant outlet 38 are symmetrically distributed along the center of the porous metal.

[0066] The guide area includes a third anode inlet guide area 41 corresponding to the third anode inlet 29, a fourth anode inlet guide area 42 corresponding to the fourth anode inlet 30, a third cathode inlet guide area 45 corresponding to the third cathode inlet 33, a fourth cathode inlet guide area 46 corresponding to the fourth cathode inlet 34, a second coolant inlet guide area 50 corresponding to the second coolant inlet 39, a third coolant inlet guide area 49 corresponding to the third coolant inlet 40, a third anode outlet guide area 44 corresponding to the third anode outlet 31, a fourth anode outlet guide area 43 corresponding to the fourth anode outlet 32, a third cathode outlet guide area 47 corresponding to the third cathode outlet 35, a fourth cathode outlet guide area 48 corresponding to the fourth cathode outlet 36, a second coolant outlet guide area 52 corresponding to the second coolant outlet 37, and a third coolant outlet guide area 51 corresponding to the third coolant outlet 38.

[0067] The third anode inlet guide area 41, the fourth anode inlet guide area 42, the third anode outlet guide area 44, the fourth anode outlet guide area 43, the second coolant inlet guide area 50, the second coolant outlet guide area 52, the third coolant inlet guide area 49 and the third coolant outlet guide area 51 are all groove structures, and the third cathode inlet guide area 45, the fourth cathode inlet guide area 46, the third cathode outlet guide area 47 and the fourth cathode outlet guide area 48 are all circular convex structures distributed in a dot matrix.

[0068] The graphite separator 27 of this embodiment is formed by milling, one side of the graphite separator 27 is an anode flow field separator, and the other side is a cathode flow field separator. The graphite separator 27 includes: an anode inlet and outlet, a cathode inlet and outlet, a coolant inlet and outlet, a groove, an anode inlet and outlet guide area, a cathode inlet and outlet guide area, a coolant inlet and outlet guide area, a sealing groove, etc. In this embodiment, the sealing groove is a second sealing groove 53.

[0069] The second coolant inlet guide area 50, the second coolant outlet guide area 52, the third coolant inlet guide area 49 and the third coolant outlet guide area 51 form a coolant channel, which can guide and distribute the cooling water so that the cooling water flows evenly through the cooling water flow field and evenly takes away the heat generated during battery operation. The gases introduced into the cathode inlet and outlet and the anode inlet and outlet are fuel gas and oxidant gas respectively. The third anode inlet guide area 41, the fourth anode inlet guide area 42, the third anode outlet guide area 44, the fourth anode outlet guide area 43, the third cathode inlet guide area 45, the fourth cathode inlet guide area 46, the third cathode outlet guide area 47 and the fourth cathode outlet guide area 48 guide the reaction gas so that the gas enters evenly and distributes the gas into the flow field.

[0070] At the same time, the cathode inlet and outlet, anode inlet and outlet, and coolant inlet and outlet that are symmetrically distributed along the center of the porous metal can shorten the flow path of the fluid in the flow field, increase the gas flow velocity at the edge position of the flow field, enhance the drainage capacity of the porous metal flow field, and make the electrochemical reaction more uniform.

[0071] In order to further improve the uniformity of fluid distribution in the flow field and enhance the drainage performance at the same time, the porosity and pore size of the porous metal in the entire flow field region can vary according to the gas flow velocity. As Figure 5 shown, the porous metal flow field is composed of three kinds of porous metals with different pore sizes, porosities, and thus different permeabilities, namely the first circular porous metal 54, the second circular porous metal 55, and the third circular porous metal 56. Since the fluid flow velocity at the edge position of the flow field is relatively large and the fluid flow velocity in the middle region of the flow field is small, the permeabilities of the first circular porous metal 54, the second circular porous metal 55, and the third circular porous metal 56 increase in sequence. The shapes of the three kinds of porous metals are circular or annular, and the processing is simple.

[0072] As described above, it is only a preferred embodiment of the present invention, and it does not impose any limitation on the technical scope of the present invention. Therefore, any minor modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A porous metal flow field plate for a fuel cell that enhances gas uniformity and drainage, characterized in that It includes a conductive separator and porous metal. A groove is provided in the middle part of the conductive separator, and the porous metal is arranged in the groove; One end of the conductive separator is provided with a fuel inlet, an oxidant inlet and a coolant inlet, and the other end is provided with a fuel outlet, an oxidant outlet and a coolant outlet. The number of the fuel inlet, the oxidant inlet, the fuel outlet and the oxidant outlet is at least two. Flow guiding areas are provided between the fuel inlet, the oxidant inlet, the coolant inlet, the fuel outlet, the oxidant outlet and the coolant outlet and the porous metal; The porous metal includes at least two kinds of porous metals with different porosity and pore diameters. The porous metal with a smaller porosity and pore diameter is arranged in the area with a larger gas flow rate in the flow field, and the porous metal with a larger porosity and pore diameter is arranged in the area with a smaller gas flow rate in the flow field; The porosity of the porous metal is 70% - 95%, and the pore diameter is 60μm - 400μm.

2. The porous metal flow field plate for a fuel cell that enhances gas uniformity and drainage according to claim 1, wherein The conductive separator is a metal separator, and the shape of the porous metal is rectangular; The number of the fuel inlets is two, namely a first anode inlet and a second anode inlet. The first anode inlet and the second anode inlet are located at the upper part of the metal separator and are symmetrically distributed along the axis of the porous metal. The number of the coolant inlets is one, namely a first coolant inlet. The first coolant inlet is located at the middle position of the top of the metal separator. The number of the oxidant inlets is two, namely a first cathode inlet and a second cathode inlet. The first cathode inlet and the second cathode inlet are symmetrically distributed along the first coolant inlet; The number of the fuel outlets is two, namely a first anode outlet and a second anode outlet. The first anode outlet and the second anode outlet are located at the lower part of the metal separator and are symmetrically distributed along the axis of the porous metal. The number of the coolant outlets is one, namely a first coolant outlet. The first coolant outlet is located at the middle position of the bottom of the metal separator. The number of the oxidant outlets is two, namely a first cathode outlet and a second cathode outlet. The first cathode outlet and the second cathode outlet are symmetrically distributed along the first coolant outlet; 3. The porous metal flow field plate for fuel cell that enhances gas uniformity and drainage according to claim 2, characterized in that, The flow guiding areas include a first anode inlet flow guiding area corresponding to the first anode inlet, a second anode inlet flow guiding area corresponding to the second anode inlet, a first cathode inlet flow guiding area corresponding to the first cathode inlet, a second cathode inlet flow guiding area corresponding to the second cathode inlet, a first coolant inlet flow guiding area corresponding to the first coolant inlet, a first anode outlet flow guiding area corresponding to the first anode outlet, a second anode outlet flow guiding area corresponding to the second anode outlet, a first cathode outlet flow guiding area corresponding to the first cathode outlet, a second cathode outlet flow guiding area corresponding to the second cathode outlet, and a first coolant outlet flow guiding area corresponding to the first coolant outlet.

4. The porous metal flow field plate for fuel cell enhancing gas uniformity and drainage according to claim 3, characterized in that, The first anode inlet flow guiding region, the second anode inlet flow guiding region, the first anode outlet flow guiding region, the second anode outlet flow guiding region, the first coolant inlet flow guiding region, and the first coolant outlet flow guiding region are all groove structures, and the first cathode inlet flow guiding region, the second cathode inlet flow guiding region, the first cathode outlet flow guiding region, and the second cathode outlet flow guiding region are all circular convex structures distributed in a dot matrix.

5. A porous metal flow field plate for a fuel cell that enhances gas uniformity and drainage, characterized in that, The conductive separator is a graphite separator, and the shapes of the graphite separator and the porous metal are both circular; The numbers of the fuel inlet, the oxidant inlet, the coolant inlet, the fuel outlet, the oxidant outlet, and the coolant outlet are all two; The fuel inlet includes a third anode inlet and a fourth anode inlet. The third anode inlet and the fourth anode inlet are arranged along the circumference of the graphite separator, and the third anode inlet and the fourth anode inlet are symmetrically distributed along the center of the circle of the porous metal; The oxidant inlet includes a third cathode inlet and a fourth cathode inlet. The third cathode inlet and the fourth cathode inlet are arranged along the circumference of the graphite separator, and the third cathode inlet and the fourth cathode inlet are symmetrically distributed along the center of the circle of the porous metal; The coolant inlet includes a second coolant inlet and a third coolant inlet. The second coolant inlet and the third coolant inlet are arranged along the circumference of the graphite separator, and the second coolant inlet and the third coolant inlet are symmetrically distributed along the center of the circle of the porous metal; The fuel outlet includes a third anode outlet and a fourth anode outlet. The third anode outlet and the fourth anode outlet are arranged along the circumference of the graphite separator, and the third anode outlet and the fourth anode outlet are symmetrically distributed along the center of the circle of the porous metal; The oxidant outlet includes a third cathode outlet and a fourth cathode outlet. The third cathode outlet and the fourth cathode outlet are arranged along the circumference of the graphite separator, and the third cathode outlet and the fourth cathode outlet are symmetrically distributed along the center of the circle of the porous metal; The coolant outlet includes a second coolant outlet and a third coolant outlet. The second coolant outlet and the third coolant outlet are arranged along the circumference of the graphite separator, and the second coolant outlet and the third coolant outlet are symmetrically distributed along the center of the circle of the porous metal.

6. The porous metal flow field plate for fuel cell enhancing gas uniformity and drainage according to claim 5, characterized in that, The flow guiding region includes a third anode inlet flow guiding region corresponding to the third anode inlet, a fourth anode inlet flow guiding region corresponding to the fourth anode inlet, a third cathode inlet flow guiding region corresponding to the third cathode inlet, a fourth cathode inlet flow guiding region corresponding to the fourth cathode inlet, a second coolant inlet flow guiding region corresponding to the second coolant inlet, a third coolant inlet flow guiding region corresponding to the third coolant inlet, a third anode outlet flow guiding region corresponding to the third anode outlet, a fourth anode outlet flow guiding region corresponding to the fourth anode outlet, a third cathode outlet flow guiding region corresponding to the third cathode outlet, a fourth cathode outlet flow guiding region corresponding to the fourth cathode outlet, a second coolant outlet flow guiding region corresponding to the second coolant outlet, and a third coolant outlet flow guiding region corresponding to the third coolant outlet.

7. A porous metal flow field plate for a fuel cell that enhances gas uniformity and drainage, characterized in that, The third anode inlet flow guiding area, the fourth anode inlet flow guiding area, the third anode outlet flow guiding area, the fourth anode outlet flow guiding area, the second coolant inlet flow guiding area, the second coolant outlet flow guiding area, the third coolant inlet flow guiding area and the third coolant outlet flow guiding area are all groove structures, and the third cathode inlet flow guiding area, the fourth cathode inlet flow guiding area, the third cathode outlet flow guiding area and the fourth cathode outlet flow guiding area are all circular convex structures distributed in a dot matrix.

8. The porous metal flow field plate for a fuel cell that enhances gas uniformity and drainage as described in claim 1, wherein A sealing groove is provided on the conductive separator, and a sealing ring is provided in the sealing groove.

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