Cathode closed type air-cooled fuel cell stack with high specific power

Abstract

The invention provides a high-specific-power cathode closed type air-cooled fuel cell stack. The high-specific-power cathode closed type air-cooled fuel cell stack comprises an air inlet end plate and a current collecting insulating plate which are sequentially stacked, a composite honeycomb cooling fin is arranged between every two single battery pack modules, and the left side and the right side of each composite honeycomb cooling fin are connected with sealing assemblies; each single battery pack module comprises an anode single-sided board, an anode sealing line, a membrane electrode, a cathode sealing line, a bipolar plate, an anode sealing line, a membrane electrode, a cathode sealing line and a cathode single-sided board which are sequentially stacked in the direction from the gas inlet end plate to the gas outlet end plate; a cathode flow field is arranged on the bipolar plate and the cathode single-sided plate, a cathode flow channel of the cathode flow field is a multi-stage branch flow channel, and a plurality of diaphragm structures are arranged in the cathode flow channel; the transverse diaphragm structure protrudes in the air flowing direction, and a hole is formed in the middle of the transverse diaphragm structure. By adopting the fin design with high heat dissipation efficiency and the water management flow field structure with high efficiency, the temperature difference of the electric pile can be greatly reduced, and the specific power of the electric pile is improved.

Description

Technical Field

[0001] The present invention relates to the field of fuel cell technology, and in particular to a high specific power cathode closed air-cooled fuel cell stack. Background Art

[0002] Traditional air-cooled fuel cells are mostly open cathode structures. The air on the cathode acts as both a reaction gas and a cooling gas. In order to remove the heat generated during the stack reaction and maintain the stack's operating temperature within an appropriate range, a large amount of air is required for heat dissipation. This also causes the cathode stoichiometry of the membrane electrode to be too large during the reaction, causing the membrane electrode to be too dry. On the other hand, the fan flow rate for heat dissipation is limited, and the heat dissipation efficiency of the open stack is limited, making it impossible to generate electricity under high-density conditions. In addition, the flow field design of the open cathode structure is limited, and it is impossible to take into account the needs of gas distribution and cooling and heat dissipation. The uniformity of the battery cannot be guaranteed, and the current density is limited. Therefore, the air-cooled point of the open cathode is difficult to balance its heat dissipation effect and internal humidity during high-density discharge, limiting the power generation efficiency and service life of the stack.

[0003] The prior art provides a cathode closed air-cooled fuel cell stack, which achieves the isolation of the cathode reaction air flow channel and the cooling air flow channel, but still has two problems of poor thermal consistency and difficult water management, which limit the high performance and long life of the battery.

[0004] In the existing technology, the inlet and outlet temperature difference of the cooling medium air of the air-cooled fuel cell is about 10~20℃ depending on the power level and area size. The cathode of the traditional open air-cooled fuel cell has the same structure as the heat dissipation, and its heat dissipation efficiency is limited. The heat dissipation of large air volume causes the membrane electrode to dry out, making it difficult to maintain high-density discharge and limiting the power density. The existing closed air-cooled fuel cell is also limited by the heat dissipation efficiency and water management problems of high-density discharge. It adopts a section-by-section cooling design, and the specific power of the stack is difficult to improve.

[0005] In view of the problems of thermal consistency in existing technologies, the structure of the cooling channel needs to be further optimized to improve the heat dissipation efficiency of the fuel cell stack and enhance the thermal consistency of the fuel cell stack. However, the water management of the fuel cell stack is difficult in the wide temperature range of air-cooled fuel cells. The existing flow field design cannot take into account low flow resistance, high drainage capacity and efficient heat dissipation, resulting in reduced battery performance or shortened life. There is currently no good solution. Summary of the invention

[0006] Based on the above-mentioned performance and life problems caused by the difficulties in water and heat management of air-cooled fuel cells, a high power density cathode closed air-cooled fuel cell stack is provided.

[0007] The technical means adopted by the present invention are as follows: A high specific power cathode closed air-cooled fuel cell stack, comprising an air intake end plate, a current collecting insulating plate, a plurality of single battery group modules and an air outlet end plate stacked in sequence; a composite honeycomb cooling fin is arranged between each plurality of single battery group modules, and a sealing assembly is connected to the left and right sides of the composite honeycomb cooling fin; The single battery module has n single batteries, n≥2, and the two single batteries include an anode single panel, an anode sealing line, a membrane electrode, a cathode sealing line, a bipolar plate, an anode sealing line, a membrane electrode, a cathode sealing line and a cathode single panel stacked in sequence from an air inlet end plate to an air outlet end plate; A cathode flow field is arranged on the bipolar plate and the cathode single plate. The cathode flow channel of the cathode flow field is a multi-stage branch flow channel. A plurality of diaphragm structures are arranged in the cathode flow channel. The diaphragm structure is convex along the air flow direction, and a hole is arranged in the middle of the diaphragm structure.

[0008] Furthermore, along the cathode flow channel direction, the spacing of the diaphragm structures is distributed in a gradient manner, with sparse spacing in the middle and dense spacing at both ends; the width of the cathode flow channel is proportional to the spacing of the diaphragm structures, and the ratio is 5 to 10 times the width of the cathode flow channel; the diaphragm structures on adjacent cathode flow channels are arranged in an alternating manner.

[0009] Furthermore, the anode single panel is a rectangular structure, and an anode flow field is provided on the side of the anode single panel facing the membrane electrode, a cathode air inlet and an anode fuel outlet are provided at the short side of one side of the anode single panel, and a cathode air outlet and an anode fuel inlet are provided at the short side of the other side of the anode single panel; the cathode single panel is a rectangular structure, and a cathode flow field is provided on the side of the cathode single panel facing the membrane electrode, a cathode air inlet and an anode fuel outlet are provided at the short side of one side of the cathode single panel, and a cathode air outlet and an anode fuel inlet are provided at the short side of the other side of the cathode single panel; the bipolar plate is a rectangular structure, and an anode flow field and a cathode flow field are provided on both sides of the bipolar plate, respectively, a cathode air inlet and an anode fuel outlet are provided at the short side of one side of the bipolar plate, and a cathode air outlet and an anode fuel inlet are provided at the short side of the other side of the bipolar plate.

[0010] Further, the anode fuel inlet and the anode fuel outlet are arranged diagonally on the rectangular structure, and the cathode air inlet and the cathode air outlet are arranged diagonally on the rectangular structure; The fuel enters from the anode fuel inlet and is discharged from the anode fuel outlet; the air enters from the cathode air inlet and is discharged from the cathode air outlet; the flow directions of the fuel and the air are opposite, forming a countercurrent.

[0011] Furthermore, the shape of the hole is one of a rectangle, a semicircle, an ellipse or a trapezoid, and the diameter of the hole ranges from 0.1 to 1.0 mm.

[0012] Furthermore, honeycomb channels are provided through the composite honeycomb cooling fins in the up and down directions, and the honeycomb channels are a single-layer honeycomb structure or a honeycomb structure of more than a single layer; along the cooling air inlet direction, the number of layers inside the honeycomb channels gradually increases, and the airflow channels gradually increase.

[0013] Furthermore, the cross section of the honeycomb channel is one of circular, elliptical, triangular, trapezoidal or rectangular, and the pore size of the honeycomb channel ranges from 0.5 mm to 5 mm.

[0014] Furthermore, the material of the composite honeycomb cooling fin is aluminum alloy, titanium alloy or stainless steel, and the surface of the composite honeycomb cooling fin is subjected to a gold-plated or carbon-plated surface treatment.

[0015] Furthermore, the thickness of the compressed sealing component matches the thickness of the composite honeycomb cooling fins.

[0016] Furthermore, the air inlet end plate and the air outlet end plate are fixed by disc springs and bolts.

[0017] Compared with the prior art, the present invention has the following advantages: The composite honeycomb cooling fin provided by the present invention has a honeycomb structure that realizes uniform heat dissipation in terms of thermal management, and branched and graded veins that accelerate local heat conduction. In terms of mechanical properties, the honeycomb matrix bears the main load, and the branched and graded veins realize stress dispersion, so that the entire fin has both efficient heat dissipation capability and sufficient compressive strength.

[0018] The flow channel of the cathode flow field provided by the present invention is provided with a diaphragm structure, which induces turbulence through local flow resistance changes, enhances mass transfer at the interface of the gas diffusion layer, and promotes drainage. The diaphragm structures on adjacent flow channels are arranged in an interlaced manner to form an interlaced mesh bamboo arrangement, so that a pressure difference is formed between adjacent flow channels, promoting mass transfer and drainage under the ridge of the battery.

[0019] The present invention adopts a fin design with high heat dissipation efficiency and a high-efficiency water management flow field structure, which can greatly reduce the temperature difference of the fuel cell stack. The water-thermal coupling optimizes the water management effect of the fuel cell stack. The one-to-many thermal management solution and the fuel cell stack integrated structure greatly improve the specific power of the fuel cell stack. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0021] Figure 1 It is an exploded view of the device of the present invention.

[0022] Figure 2 It is a schematic diagram of the integrated fastening structure of the battery stack of the present invention.

[0023] Figure 3 It is a schematic diagram of assembling multiple single cell group modules and honeycomb fins of the present invention.

[0024] Figure 4 This is a diagram of the cathode flow field structure of the present invention.

[0025] Figure 5 This is a structural diagram of the anode flow field of the present invention.

[0026] Figure 6 It is a vertical view of the diaphragm of the present invention.

[0027] Figure 7 This is a flat view of the diaphragm of the present invention.

[0028] Figure 8 This is the overall structure diagram of the composite honeycomb cooling fin of the present invention.

[0029] Fig. 9 It is a schematic diagram of the graded end surface changes of the composite honeycomb cooling fin of the present invention.

[0030] In the figure: 1. Air inlet end plate; 2. Air outlet end plate; 3. Current collecting insulating plate; 4. Anode single panel; 5. Anode sealing line; 6. Membrane electrode; 7. Cathode sealing line; 8. Bipolar plate; 9. Cathode single panel; 10. Sealing assembly; 11. Composite honeycomb cooling fins; 12. Bolts; 13. Disc spring; 81. Cathode air inlet; 82. Anode fuel outlet; 83. Anode fuel inlet; 84. Cathode air outlet; 85. Diaphragm structure; 86. Anode flow field. DETAILED DESCRIPTION

[0031] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0032] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0034] Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, the numerical expressions and numerical values ​​do not limit the scope of the present invention. At the same time, it should be clear that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be regarded as part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0035] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention: the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0036] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below their position devices or structures". Thus, the exemplary term "above" may include both "above" and "below". The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0037] like Figure 1 and Figure 2 As shown, the present invention provides a high specific power cathode closed air-cooled fuel cell stack, comprising an air intake end plate 1, a current collecting insulating plate 3, a plurality of single battery group modules and an air outlet end plate 2 stacked in sequence; a composite honeycomb cooling fin 11 is arranged between each plurality of single battery group modules, and a sealing assembly 10 is connected to the left and right sides of the composite honeycomb cooling fin 11, and a plurality of adjacent single battery group modules are stacked together by the composite honeycomb cooling fin 11 and the sealing assembly 10, as shown in FIG. Figure 3 The composite honeycomb cooling fins dissipate heat for adjacent multiple single battery modules, and the compression ratio of the sealing component 10 is designed so that the thickness after compression matches the thickness of the composite honeycomb cooling fins.

[0038] The composite honeycomb cooling fin 11 is provided with honeycomb channels in the vertical direction, and the honeycomb channels are a single-layer honeycomb structure or a honeycomb structure with more than a single layer, such as Figure 8 and Fig. 9 As shown; along the cooling air intake direction, the number of internal layers of the honeycomb channel gradually increases, and the airflow channel gradually increases. The cross-section of the honeycomb channel is one of circular, elliptical, triangular, trapezoidal or rectangular, and the aperture range of the honeycomb channel is 0.5mm~5mm. The material of the composite honeycomb cooling fin 11 is aluminum alloy, titanium alloy or stainless steel, and the surface of the composite honeycomb cooling fin 11 is subjected to gold plating or carbon plating. To reduce the contact resistance between the composite honeycomb cooling fin and the electrode plate, and play an anti-corrosion role. The composite honeycomb cooling fin 11 can be a single-layer honeycomb, a two-layer honeycomb or more-layer honeycomb fin. The number of honeycomb layers is determined by the heat dissipation requirements of the battery stack. In terms of thermal management, the honeycomb structure realizes uniform heat dissipation, and the branched and graded veins accelerate local heat conduction. In terms of mechanical properties, the honeycomb matrix bears the main load, and the branched and graded veins realize stress dispersion, so that the entire fin has both efficient heat dissipation capability and sufficient compressive strength; The single battery module has n single batteries, n≥2, and the two single batteries include an anode single panel, an anode sealing line, a membrane electrode, a cathode sealing line, a bipolar plate, an anode sealing line, a membrane electrode, a cathode sealing line and a cathode single panel stacked in sequence from an air inlet end plate to an air outlet end plate; The bipolar plate 8 and the cathode single plate 9 are provided with a cathode flow field, such as Figure 4 The cathode flow field is designed based on bionics, imitating the fractal structure of the vascular bundle of bamboo stems. The cathode flow channel is designed as a multi-level branch flow channel, and a raised "bamboo node" diaphragm structure 85 is periodically arranged in the flow channel, as shown in FIG. Figure 6 and Figure 7 As shown. Turbulence is induced by local flow resistance changes, which enhances mass transfer at the interface of the gas diffusion layer and promotes drainage. There are holes in the middle of the bamboo-node diaphragm, and the hole shape can be any shape within the diameter range of 0.1~1.0mm, such as rectangle, semicircle, ellipse or trapezoid; the distribution pattern of the bamboo-node structure is that along the flow channel direction, the bamboo-node spacing is a gradient distribution with sparse in the middle and dense at both ends, and the larger the flow channel width, the wider the bamboo-node spacing, and the ratio is 5~10 times the flow channel width, and the diaphragm structures on adjacent flow channels are staggered to form a staggered mesh bamboo-node arrangement, so that a pressure difference is formed between adjacent flow channels, which promotes the sub-ridge mass transfer and drainage of the battery; The anode single panel 4 is a rectangular structure, such as Figure 5 As shown. The anode single panel 4 is provided with an anode flow field 86 on the side facing the membrane electrode 6, a cathode air inlet 81 and an anode fuel outlet 82 are provided on one short side of the anode single panel 4, and a cathode air outlet 84 and an anode fuel inlet 83 are provided on the other short side of the anode single panel 4; the cathode single panel 9 is a rectangular structure, a cathode flow field is provided on the side facing the membrane electrode 6 of the cathode single panel 9, a cathode air inlet 81 and an anode fuel outlet 82 are provided on one short side of the cathode single panel 9, and a cathode air outlet 84 and an anode fuel inlet 83 are provided on the other short side of the cathode single panel 9; the bipolar plate 8 is a rectangular structure, an anode flow field 86 and a cathode flow field are provided on both sides of the bipolar plate 8, a cathode air inlet 81 and an anode fuel outlet 82 are provided on one short side of the bipolar plate 8, and a cathode air outlet 84 and an anode fuel inlet 83 are provided on the other short side of the bipolar plate 8. The anode fuel inlet 83 is diagonally arranged with the anode fuel outlet 82 on the rectangular structure, and the cathode air inlet 81 is diagonally arranged with the cathode air outlet 84 on the rectangular structure; the fuel enters from the anode fuel inlet 83 and is discharged from the anode fuel outlet 82; the air enters from the cathode air inlet 81 and is discharged from the cathode air outlet 84; the flow directions of the fuel and the air are opposite, forming a countercurrent. The reaction heat of the stack is transferred from the pole plate to the composite honeycomb cooling fins, and then the heat is extracted by the cooling air passing through the composite honeycomb cooling fins.

[0039] The fuel cell stack is fastened with disc springs 13 and bolts 12. The disc springs 13 can compensate for the deformation of the fuel cell stack during high and low temperature cycles, reduce the impact vibration of the fuel cell stack and the stress attenuation of elastic components during high and low temperature cycles, and ensure the reliability of fuel cell stack assembly and fastening.

[0040] The cathode closed air-cooled fuel cell in the following embodiment adopts a fin design with high heat dissipation efficiency and a high-efficiency water management flow field structure, which can greatly reduce the temperature difference of the fuel cell stack. The water-thermal coupling optimizes the water management effect of the fuel cell stack. The one-to-many thermal management solution and the fuel cell stack integrated structure greatly improve the specific power of the fuel cell stack.

[0041] Example A cathode closed air-cooled fuel cell stack, comprising an air inlet end plate 1, an air outlet end plate 2, a current collecting insulating plate 3, and a plurality of single cell modules stacked between two current collecting insulating plates 3; the single cell module has two combinations of 2 single cells and 3 single cells, the 2 single cell module is composed of an anode single panel 4, an anode sealing line 5, a membrane electrode 6, a cathode sealing line 7, a bipolar plate 8, an anode sealing line 5, a membrane electrode 6, a cathode sealing line 7 and a cathode single panel 9, and the 3 single cell module is composed of an anode single panel 4, an anode sealing line 5, a membrane electrode 6, a cathode sealing line 7, a bipolar plate 8, an anode sealing line 5, a membrane electrode 6, a cathode sealing line 7, a bipolar plate 8, an anode sealing line 5, a membrane electrode 6. The cathode sealing line 7 and the cathode single panel 9 are stacked. Multiple single battery modules are stacked in an alternating order of 3 sections, 2 sections, 3 sections, 2 sections and 3 sections. The sealing component 10 and the composite honeycomb cooling fin 11 are matched. The compression rate of the sealing component 10 is 25%, and the thickness tolerance of the composite honeycomb cooling fin is controlled at ±0.05mm. The primary aperture of the main channel of the composite honeycomb cooling fin is 1.3mm, the secondary aperture is 1.0mm, and the tertiary aperture is 0.7mm. The heat dissipation area is increased by 3-5 times. During battery operation, the fan is installed on one side of the composite honeycomb cooling fin channel. The composite honeycomb cooling fin is combined with a forced convection fan to achieve active-passive composite heat dissipation, and the temperature difference of a single battery is less than 5°C. At the same time, in this embodiment, the gas flow channels of the anode and cathode plates are independent of the cooling air flow channels; the cathode flow field adopts a one-to-two graded branch flow channel design, and 5 diaphragm structures are arranged on each branch flow channel. The relative positions of adjacent diaphragm structures are staggered, forming a mesh diaphragm structure distribution in the entire flow field area, which promotes the discharge of liquid water under the ridge, and the drainage efficiency is improved by 38%; the anode fuel enters from the short side air inlet, and the cathode air enters from the short side air inlet on the other side, and the two flow in a countercurrent direction, and the temperature difference is used to achieve self-balanced humidity control, so that the fluctuation of the water content of the membrane electrode 6 is ≤±3%; In addition, the M3 bolt 12 used in this embodiment is matched with the Ф3.2 disc spring 13, with a preload of 5000N, which can compensate for thermal deformation at -30~80℃, with a deformation of ≤0.08mm, and can ensure that the contact resistance remains stable (fluctuation ≤1mΩ·cm) under a 30Hz vibration environment. 2 ).

[0042] The air-cooled fuel cell stack assembled with this structural design can achieve a single stack power of up to 1300W / kg and an operating electrical density of 1500mA / cm 2 , much higher than the 700W / kg specific power and 500~600mA / cm of conventional open air-cooled fuel cell stacks. 2 Working electrical secret.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high specific power cathode closed air-cooled fuel cell stack, characterized in that: It includes an air intake end plate, a current collecting insulating plate, a plurality of single battery group modules and an air outlet end plate stacked in sequence; a composite honeycomb cooling fin is arranged between each plurality of single battery group modules, and a sealing component is connected to the left and right sides of the composite honeycomb cooling fin; The single battery module has n single batteries, n≥2, and the two single batteries include an anode single panel, an anode sealing line, a membrane electrode, a cathode sealing line, a bipolar plate, an anode sealing line, a membrane electrode, a cathode sealing line and a cathode single panel stacked in sequence from an air inlet end plate to an air outlet end plate; A cathode flow field is arranged on the bipolar plate and the cathode single plate. The cathode flow channel of the cathode flow field is a multi-stage branch flow channel. A plurality of diaphragm structures are arranged in the cathode flow channel. The diaphragm structure is convex along the air flow direction, and a hole is arranged in the middle of the diaphragm structure.

2. The high specific power cathode closed air-cooled fuel cell stack according to claim 1, characterized in that: Along the cathode flow channel, the spacing of the diaphragm structures is distributed in a gradient manner, with sparse spacing in the middle and dense spacing at both ends; the width of the cathode flow channel is proportional to the spacing of the diaphragm structures, and the ratio is 5 to 10 times the width of the cathode flow channel; the diaphragm structures on adjacent cathode flow channels are arranged in an alternating manner.

3. The high specific power cathode closed air-cooled fuel cell stack according to claim 1, characterized in that: The anode single panel is a rectangular structure, and an anode flow field is arranged on the side of the anode single panel facing the membrane electrode, a cathode air inlet and an anode fuel outlet are arranged on one short side of the anode single panel, and a cathode air outlet and an anode fuel inlet are arranged on the other short side of the anode single panel; the cathode single panel is a rectangular structure, and a cathode flow field is arranged on the side of the cathode single panel facing the membrane electrode, a cathode air inlet and an anode fuel outlet are arranged on one short side of the cathode single panel, and a cathode air outlet and an anode fuel inlet are arranged on the other short side of the cathode single panel; the bipolar plate is a rectangular structure, and an anode flow field and a cathode flow field are respectively arranged on both sides of the bipolar plate, a cathode air inlet and an anode fuel outlet are arranged on one short side of the bipolar plate, and a cathode air outlet and an anode fuel inlet are arranged on the other short side of the bipolar plate.

4. The high specific power cathode closed air-cooled fuel cell stack according to claim 3, characterized in that: The anode fuel inlet and the anode fuel outlet are arranged diagonally on the rectangular structure, and the cathode air inlet and the cathode air outlet are arranged diagonally on the rectangular structure; The fuel enters from the anode fuel inlet and is discharged from the anode fuel outlet; Air enters from the cathode air inlet and is discharged from the cathode air outlet; the flow directions of fuel and air are opposite, forming a countercurrent.

5. The high specific power cathode closed air-cooled fuel cell stack according to claim 1, characterized in that: The shape of the hole is one of rectangle, semicircle, ellipse or trapezoid, and the diameter of the hole ranges from 0.1 to 1.0 mm.

6. The high specific power cathode closed air-cooled fuel cell stack according to claim 1, characterized in that: The composite honeycomb cooling fins are penetrated by honeycomb channels in the up and down directions. The honeycomb channels are a single-layer honeycomb structure or a honeycomb structure with more than a single layer. Along the cooling air inlet direction, the number of layers inside the honeycomb channels gradually increases, and the airflow channels gradually increase.

7. The high specific power cathode closed air-cooled fuel cell stack according to claim 6, characterized in that: The cross section of the honeycomb channel is one of circular, elliptical, triangular, trapezoidal or rectangular, and the aperture range of the honeycomb channel is 0.5mm~5mm.

8. The high specific power cathode closed air-cooled fuel cell stack according to claim 1, characterized in that: The material of the composite honeycomb cooling fin is aluminum alloy, titanium alloy or stainless steel, and the surface of the composite honeycomb cooling fin is subjected to gold plating or carbon plating.

9. The high specific power cathode closed air-cooled fuel cell stack according to claim 1, characterized in that: The thickness of the sealing component after compression matches the thickness of the composite honeycomb cooling fin.

10. The high specific power cathode closed air-cooled fuel cell stack according to claim 1, characterized in that: The air inlet end plate and the air outlet end plate are fixed by disc springs and bolts.

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