A fuel cell plate structure, a fuel cell single cell, a fuel cell stack, and a vehicle

Abstract

The present invention relates to a fuel cell plate structure, a fuel cell single cell, a fuel cell stack and a vehicle. The fuel cell plate structure includes an air intake distribution area and a reaction flow field area. The reaction flow field area includes a plurality of basic flow channels. Each basic flow channel includes a plurality of straight flow segments and a plurality of variable cross-section flow segments arranged at intervals. The variable cross-section flow segments on two adjacent basic flow channels are staggered, and the plurality of variable cross-section flow segments on the basic flow channel are arranged gradually denser along the gas flow direction. The gas is redistributed through the air intake distribution area so that the gas enters the reaction flow field area evenly. When the gas flows through the variable cross-section flow segment, the local gas flow rate and local resistance can be increased, thereby enhancing the mass transfer of the gas to the membrane electrode. The staggered distribution of the variable cross-section flow segments laterally is beneficial to the uniformity of the gas concentration distribution of the whole plate. The use of the gradually denser arranged variable cross-section flow segments can effectively enhance the drainage capacity and the uniformity of the current density distribution in the latter half of the basic flow channel.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and particularly relates to a fuel cell plate structure, a fuel cell single cell, a fuel cell stack and a vehicle. Background Art

[0002] Proton exchange membrane fuel cells have advantages such as high power generation efficiency and environmental friendliness, and have broad application prospects. An efficient water and heat management system is of great significance for improving the performance of fuel cells and extending their lifespan. The bipolar plate is a key component of proton exchange membrane fuel cells. On the one hand, the flow field on the bipolar plate can evenly distribute gas to the gas diffusion layer, so that the current density and temperature generated by the electrochemical reaction are evenly distributed; on the other hand, it discharges the generated water from the stack in a timely manner. Therefore, the reasonable design of the flow field is very important for improving the performance of fuel cell water and heat management.

[0003] At present, the common flow fields of proton exchange membrane fuel cells mainly include parallel flow fields, serpentine flow fields, and interdigitated flow fields, etc. The characteristic of the interdigitated flow channel is that the flow channel is discontinuous. During the gas flow process, due to the blockage of the channel, the gas is forced to diffuse into the surrounding flow channels. This process enables more gas to enter the catalytic layer for reaction, which is beneficial to improving gas utilization efficiency and power density. However, when the gas passes through the diffusion layer for forced diffusion, a large pressure drop will be generated. If the gas flow is too large, forced convection may damage the gas diffusion layer, thereby reducing the battery performance; the parallel flow field is widely used in fuel cells, but its small pressure drop and many branched flow channels make the flow of reaction gas in the entire flow field very uneven, and the mass transfer of reaction gas in the flow field is poor, seriously affecting the output power of the battery. Moreover, when the flow channel of the parallel flow field is too wide, problems such as uneven gas distribution and difficult drainage are likely to occur; the serpentine flow field has a good drainage effect, but its flow path is long, the pressure drop is large, and the gas mainly undergoes electrochemical reactions in the front section of the serpentine flow channel, while there is insufficient reaction gas in the rear section of the flow channel, affecting the performance of the fuel cell.

[0004] Therefore, there is an urgent need to propose a flow field structure for fuel cells to overcome problems such as uneven gas distribution, difficult drainage, and uneven temperature distribution after the gas enters the flow field of the fuel cell reaction area, thereby improving the performance of the fuel cell. Summary of the Invention

[0005] One of the purposes of the present invention is to provide a fuel cell plate structure to solve problems such as uneven gas distribution, difficult drainage, and uneven temperature distribution existing in the existing fuel cell plate structure; the second purpose is to provide a fuel cell single cell; the third purpose is to provide a fuel cell stack; the fourth purpose is to provide a vehicle.

[0006] To achieve the above purposes, the technical solutions adopted by the present invention are as follows:

[0007] The plate body, with an air inlet and an air outlet respectively provided at both ends of the plate body along the length direction;

[0008] The flow field, arranged on the plate body and located between the air inlet and the air outlet, and the flow field is respectively communicated with the air inlet and the air outlet;

[0009] The flow field at least includes an air inlet duct, an air inlet distribution area and a reaction flow field area arranged in sequence along the length direction of the plate body. The air inlet duct is used to introduce gas from the air inlet into the air inlet distribution area, and the air inlet distribution area is used to make the gas evenly distributed and flow into the reaction flow field area;

[0010] The reaction flow field area includes a plurality of basic flow channels arranged side by side along the width direction of the plate body. The basic flow channels include a plurality of straight flow segments and a plurality of variable cross-section flow segments arranged at intervals along the length direction of the plate body. The variable cross-section flow segments on two adjacent basic flow channels are staggered along the length direction of the plate body, and the plurality of variable cross-section flow segments on the basic flow channels are arranged gradually densely along the gas flow direction.

[0011] Optionally, the flow field further includes an air outlet distribution area and an air outlet duct. The air outlet distribution area is arranged on the plate body, and the air outlet distribution area is symmetrically arranged with the air inlet distribution area about the center of the reaction flow field area. The air outlet distribution area is used to converge the gas discharged from the reaction flow field area into the air outlet duct, and the air outlet duct is used to guide the gas from the air outlet distribution area to the air outlet for discharge.

[0012] Optionally, a plurality of the air inlet ducts are arranged between the air inlet and the air inlet distribution area, and a plurality of the air outlet ducts are arranged between the air outlet and the air outlet distribution area. The plurality of air inlet ducts and the plurality of air outlet ducts are both arranged in a fan shape along the width direction of the plate body; the width of the air inlet duct and the air outlet duct is 0.8 - 2 mm, the depth is 0.2 - 0.3 mm, and the length is 5 - 15 mm.

[0013] Optionally, both the intake distribution area and the outlet distribution area include a plurality of hierarchical diversion structures and branch diversion structures arranged side by side. The hierarchical diversion structure includes at least a primary diversion channel and a secondary diversion channel, and the branch diversion structure includes at least a first branch structure and a second branch structure. The first branch structure is configured to divide the secondary diversion channel into a first branch channel and a second branch channel, and the second branch structure is configured to divide the first branch channel or the second branch channel into a third branch channel and a fourth branch channel. The primary diversion channel, the secondary diversion channel, the first branch channel, the second branch channel, the third branch channel, and the fourth branch channel form gas distribution channels in the intake distribution area and the outlet distribution area. The sizes of the gas distribution channels arranged side by side on the plate body are the same, and the depth of the gas distribution channels is 0.32 to 0.45 mm.

[0014] Optionally, an intake transition channel is provided between the intake distribution area and the intake duct, and an outlet transition channel is provided between the outlet distribution area and the outlet duct. The widths of the intake transition channel and the outlet transition channel are 1 to 2 mm, and the depths are 0.32 to 0.45 mm.

[0015] Optionally, the angle between the primary diversion channel and the long axis of the plate body is α1, where α1 is 0 to 15°; the angle between the secondary diversion channel and the short axis of the plate body is α2, where α2 is 5 to 20°; the angle α3 between the intake duct and the primary diversion channel is 5 to 20°.

[0016] At the first branch structure, the angle between the first branch channel and the second branch channel is β1, where β1 is 55 to 85°; at the second branch structure, the angle between the third branch channel and the fourth branch channel is β2, where β2 is 15 to 40°; the angle β3 between the first branch channel, the second branch channel and the basic channel is 5 to 20°.

[0017] Optionally, the spacing width between two adjacent primary diversion channels is 1.5 to 2 mm. At 1 / 2h of the cross-section of the primary diversion channel along the thickness direction of the plate body, the width of the primary diversion channel is 0.8 to 1.5 mm, the ridge width is 0.5 to 0.9 mm, the draft angle is 20 to 30°, the upper R angle is 0.2 to 0.3 mm, the lower R angle is 0.15 to 0.25, and the ratio of the width of the primary diversion channel to the ridge width is in the range of 1.1:1 to 2.4:1.

[0018] Optionally, the spacing width between two adjacent secondary diversion channels is 1.2 to 1.8 mm. At 1 / 2h of the cross-section of the secondary diversion channel along the thickness direction of the plate body, the width of the secondary diversion channel is 0.8 to 1.5 mm, the ridge width is 0.45 to 0.8 mm, the draft angle is 20 to 25°, the upper R angle is 0.2 to 0.25 mm, the lower R angle is 0.15 to 0.2, and the ratio of the width of the secondary diversion channel to the ridge width is 1.5:1 to 3:1.

[0019] Optionally, the spacing width between the first branch channel and the second branch channel is 1.9 to 2.4 mm. At 1 / 2h of the cross-section of the first branch channel and the second branch channel along the thickness direction of the plate body, the widths of the first branch channel and the second branch channel are both 0.55 to 0.9 mm, the ridge width is 1 to 1.85 mm, the draft angle is 20 to 25°, the upper R angle is 0.15 - 0.3 mm, the lower R angle is 0.1 to 0.2 mm, and the ratio of the widths of the first branch channel and the second branch channel to the ridge width is 1.7:1 to 3.3:1.

[0020] Optionally, the spacing width between two adjacent basic channels is 0.99 to 1.2 mm, the length of the basic channel is 220 - 245 mm, the number of the basic channels is 70 to 85, and the ratio of the length to the width of the reaction flow field area is 2.4:1 to 3.3:1.

[0021] Optionally, in the DC section, the depth of the basic channel is 0.3 to 0.4 mm. At 1 / 2h of the cross-section of the DC section along the thickness direction of the plate body, the width of the basic channel is 0.55 to 0.7 mm, the ridge width is 0.4 to 0.5 mm, the draft angle of the basic channel is 20 to 25°, the upper R angle is 0.15 to 0.3 mm, the lower R angle is 0.1 to 0.2 mm, and the ratio of the width of the basic channel to the ridge width is 1.25:1 to 1.75:1.

[0022] Optionally, there is a narrowest point on the variable runoff section. The starting end and the ending end of the variable runoff section are both connected to the DC section. From the starting end and the ending end of the variable runoff section to the narrowest point, the depth and width of the basic channel gradually decrease. At the narrowest point of the variable runoff section, the depth of the basic channel is 0.12 to 0.25 mm. At 1 / 2h of the cross-section of the variable runoff section along the thickness direction of the plate body, the width at the narrowest point of the variable runoff section is 0.14 to 0.25 mm.

[0023] Optionally, the variable flow path section extends in the gas flow direction with a length of 4 to 8 mm. Each of the basic flow channels includes 6 to 10 variable flow path sections. The 6 to 10 variable flow path sections gradually become denser in the gas flow direction and are arranged in an arithmetic progression, with a distance tolerance of 1 to 5 mm.

[0024] Optionally, in the gas flow direction, the length of the straight flow section in front of the first variable flow path section is 10 to 70 mm, and the length of the straight flow section behind the last variable flow path section is 1 to 10 mm. The variable flow path sections on two adjacent basic flow channels in the reaction flow field area are arranged alternately, and the alternating interval distance is 0.5 to 2.5 mm.

[0025] A fuel cell single cell structure includes a membrane electrode, an anode plate, and the fuel cell plate structure as described above. The fuel cell plate structure, the membrane electrode, and the anode plate are stacked in sequence to form the fuel cell single cell;

[0026] Or it includes a membrane electrode and two fuel cell plate structures as described above. The fuel cell single cell is formed by stacking the fuel cell plate structure, the membrane electrode, and the fuel cell plate structure in sequence.

[0027] A fuel cell stack includes a plurality of the fuel cell single cell structures. The plurality of fuel cell single cell structures are stacked in sequence to form the fuel cell stack.

[0028] A vehicle includes the fuel cell stack as described above.

[0029] Advantages of the present invention: The gas enters the intake distribution area through the intake duct for diversion from the intake port. The intake distribution area needs to evenly distribute the gas converged at the intake port to the reaction flow field area. At the same time, the pressure of the gas decreases due to energy loss during the process of reaching the reaction flow field area. By distributing the gas through the intake distribution area, the fluid can maintain a uniform intake pressure and flow rate when entering the reaction flow field area, so that the gas can enter the reaction flow field area evenly; for the gas that enters the reaction flow field area evenly, during the process of flowing from the intake end to the outlet end of the reaction flow field area, the fluid has energy loss resulting in pressure reduction, leading to poor mass transfer efficiency and low reaction efficiency of the gas in the latter section of the reaction flow field area. And with the increase of the liquid water generated by the reaction, the water generated by the reaction is not easy to discharge, easily causing a flooding phenomenon, and the reaction load in the front section is large, resulting in local high heat, which is easy to cause damage to the electrode plate; by designing the basic flow channels as staggered straight-flow sections and variable-flow sections along the gas flow direction, and arranging multiple variable-flow sections on the basic flow channels to be gradually denser along the gas flow direction; since variable-flow sections are provided in the reaction flow field area, when the gas flows through the variable-flow sections, the local gas flow rate and local resistance can be increased. With the sudden increase of the local pressure drop at the variable-flow sections, the reaction gas is forced to flow into the gas diffusion electrode, thereby enhancing the mass transfer in the gas diffusion electrode; due to the sudden reduction of the cross-sectional area of the basic flow channel at the variable-flow sections, under the action of the local pressure gradient, eddies occur near the structure of the variable-flow sections, especially at the back. These eddies greatly promote the mixing of the gas in the basic flow channels, making the distribution of the oxygen partial pressure more uniform in the channel depth direction; since the neatly arranged variable-flow sections limit the mass transfer between adjacent basic flow channels, for the neatly arranged variable-flow sections, the pressure distributions in the gas flow directions of each basic flow channel are the same, so there is no static pressure difference driving the in-plane mass convection between adjacent basic flow channels. Therefore, the variable-flow sections are distributed horizontally and staggered, which is more conducive to the uniformity of the gas concentration distribution of the whole plate; by using variable-flow sections that are gradually denser along the gas flow direction, the drainage capacity of the latter half of the basic flow channels can be effectively enhanced, and the uniformity of the gas concentration distribution and the current density distribution of the whole plate can be improved. Description of the Drawings

[0030] Figure 1 It shows a schematic structural diagram of the fuel cell electrode plate structure towards the membrane electrode side shown in the embodiment of the present application;

[0031] Figure 2 It shows as Figure 1 an enlarged schematic diagram of the structure of part A in;

[0032] Figure 3 It shows a schematic structural diagram of the flow field shown in the embodiment of the present application;

[0033] Figure 4 It shows a schematic structural diagram of the intake distribution area or the outlet distribution area shown in the embodiment of the present application;

[0034] Figure 5 It shows a partially enlarged schematic view of the gas distribution flow channel shown in the embodiment of the present application;

[0035] Figure 6 It shows a partially enlarged schematic view of the reaction flow field region shown in the embodiment of the present application;

[0036] Figure 7 It shows an axonometric structural schematic view of the variable flow diameter section shown in the embodiment of the present application;

[0037] Figure 8 It shows a left view of the variable flow diameter section shown in the embodiment of the present application.

[0038] Description of the reference numerals

[0039] Plate body 1, air inlet 101, air inlet 101a, hydrogen inlet 101b, air outlet 102, air outlet 102a, hydrogen outlet 102b, water inlet 103, water outlet 104, flow field 2, intake distribution area 201, reaction flow field area 202, basic flow channel 2021, direct current section 2021a, variable flow diameter section 2021b, air outlet distribution area 203, intake duct 204, air outlet duct 205, intake transition channel 206, air outlet transition channel 207, grading and guiding structure 3, first-stage guiding flow channel 301, second-stage guiding flow channel 302, branch guiding structure 4, first branch structure 401, second branch structure 402, first branch flow channel 5, second branch flow channel 6, third branch flow channel 7, fourth branch flow channel 8. Detailed implementation manners

[0040] The following will describe the implementation manners of the present invention with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for explaining the present invention and not for limiting the protection scope of the present invention.

[0041] It should be noted that the diagrams provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner. Therefore, only the components related to the present invention are shown in the diagrams, rather than being drawn according to the number, shape, and size of the components in actual implementation. The types, quantities, and proportions of the components in actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0042] It should be noted that the fuel cell plate structure shown in the embodiments of the present application is specifically applied to the cathode plate of the fuel cell plate and is located on the side of the cathode plate facing the membrane electrode in the thickness direction; however, it is not limited to being only applied to the cathode plate and can be simultaneously arranged on both the cathode plate and the anode plate, and are both located on the sides of the cathode plate and the anode plate facing the membrane electrode.

[0043] Please refer to Figures 1 to 8 As shown, the present application provides a fuel cell plate structure.

[0044] In an exemplary embodiment of the present application, the fuel cell plate structure includes: a plate body 1, with an air inlet 101 and an air outlet 102 respectively provided at both ends of the plate body 1 in the length direction; a flow field 2, arranged on the plate body 1 and located between the air inlet 101 and the air outlet 102, and the flow field 2 is respectively communicated with the air inlet 101 and the air outlet 102; the flow field 2 at least includes an air inlet duct 204, an air inlet transition channel 206, an air inlet distribution area 201, and a reaction flow field area 202 arranged in sequence along the length direction of the plate body 1. The air inlet duct 204 and the air inlet transition channel 206 are used to introduce gas from the air inlet 101 into the air inlet distribution area 201, and the air inlet distribution area 201 is used to evenly distribute the gas and flow it into the reaction flow field area 202; the reaction flow field area 202 includes a plurality of basic flow channels 2021 arranged side by side along the width direction of the plate body 1. The basic flow channels 2021 include a plurality of straight flow segments 2021a and a plurality of variable flow segments 2021b arranged at intervals along the length direction of the plate body 1. The variable flow segments 2021b on two adjacent basic flow channels 2021 are staggered along the length direction of the plate body 1, and the plurality of variable flow segments 2021b on the basic flow channels 2021 are arranged gradually densely along the gas flow direction.

[0045] In this embodiment, the plate body 1 is a cathode plate. The two ends of the cathode plate along the long axis are respectively arranged as a fluid inlet and a fluid outlet. The air inlet 101 includes a hydrogen inlet 101b and an air inlet 101a. A water inlet 103 is arranged between the hydrogen inlet 101b and the air inlet 101a. The air outlet 102 includes a hydrogen outlet 102b and an air outlet 102a. A water outlet 104 is arranged between the hydrogen outlet 102b and the air outlet 102a. The flow field 2 is arranged in the middle of the plate body 1, and the flow field 2 is respectively communicated with the air inlet 101a and the air outlet 102a.The gas is introduced into the intake distribution area 201 from the intake port 101 through the intake duct 204. There is an intake transition passage 206 between the inlet of the primary diversion flow passage 301 in the intake distribution area 201 and the inlet of the intake duct 204. The shape of the intake transition passage 206 is consistent with the edge shape of the intake duct 204 and is arc-shaped, which can make the gas be transmitted to the intake distribution area 201 more evenly. During the process of the gas reaching the reaction flow field area 202, the pressure decreases due to energy loss. The gas is redistributed through the intake distribution area 201, so that the fluid can maintain a uniform intake pressure when entering the reaction flow field area 202, thus enabling the gas to enter the reaction flow field area 202 evenly; the gas that enters the reaction flow field area 202 evenly has its pressure decreased due to energy loss during the process of flowing towards the outlet port 102, and more and more reaction water is generated by the reaction, resulting in poor mass transfer efficiency and low reaction efficiency in the latter section of the reaction flow field area 202, and the water generated by the reaction is not easy to discharge, which is likely to cause a flooding phenomenon, and the reaction load in the front section of the reaction flow field area 202 is large, with local high heat, which is likely to cause damage to the electrode plate; by designing the basic flow passage 2021 as a straight flow section 2021a and a variable cross-section flow section 2021b along the gas flow direction, and the variable cross-section flow sections 2021b between adjacent two basic flow passages 2021 are arranged alternately along the gas flow direction, and a plurality of variable cross-section flow sections 2021b on the basic flow passage 2021 are arranged gradually densely along the gas flow direction; because the reaction flow field area 202 is provided with variable cross-section flow sections 2021b, when the gas flows through the variable cross-section flow sections 2021b, the local gas flow rate and local resistance can be increased. With the sudden increase of the local pressure drop at the variable cross-section flow sections 2021b, the reaction gas is forced to flow into the gas diffusion electrode, thus enhancing the mass transfer in the gas diffusion electrode; because the cross-sectional area of the basic flow passage 2021 suddenly shrinks at the variable cross-section flow sections 2021b, under the action of the local pressure gradient, eddies occur near the structure of the variable cross-section flow sections 2021b, especially at the back. These eddies greatly promote the mixing of the gas in the basic flow passage 2021, making the distribution of the oxygen partial pressure more uniform in the channel depth direction; because the neatly arranged variable cross-section flow sections 2021b limit the mass transfer between adjacent basic flow passages 2021, for the neatly arranged variable cross-section flow sections 2021b, the pressure distributions in the gas flow directions of each basic flow passage 2021 are the same, so there is no static pressure difference that drives mass convection in the driving surface between adjacent basic flow passages 2021. Therefore, the variable cross-section flow sections 2021b are distributed horizontally and crosswise to enhance the mutual flow of the gas between adjacent flow passages, which is more conducive to the uniformity of the gas concentration distribution of the whole plate; by using the variable cross-section flow sections 2021b that are arranged gradually densely along the gas flow direction, the drainage capacity of the latter half of the basic flow passage 2021 can be effectively enhanced, and the uniformity of the gas concentration distribution and the current density distribution of the whole plate can be improved.

[0046] In an exemplary embodiment of the present application, the flow field 2 further includes an air outlet distribution area 203, an air outlet transition channel 207, and an air outlet duct 205. The air outlet distribution area 203 is provided on the plate body 1, and the air outlet duct 205, the air outlet transition channel 207, and the air outlet distribution area 203 are symmetrically arranged about the center of the reaction flow field area 202 with respect to the air inlet duct 204, the air inlet transition channel 206, and the air inlet distribution area 201. The air outlet distribution area 203 is used to converge the gas discharged from the reaction flow field area 202 into the air outlet duct 205, and the air outlet duct 205 is used to guide the gas from the air outlet distribution area 203 to the air outlet 102 for discharge.

[0047] In this embodiment, the air outlet distribution area 203 can enable the uniform discharge of gas, avoid gas accumulation and excessive pressure, thereby improving the safety of the fuel cell system.

[0048] In an exemplary embodiment of the present application, a plurality of air inlet ducts 204 are provided between the air inlet 101 and the air inlet distribution area 201, and a plurality of air outlet ducts 205 are provided between the air outlet 102 and the air outlet distribution area 203. The plurality of air inlet ducts 204 and the plurality of air outlet ducts 205 are arranged in a fan shape along the width direction of the plate body 1; the width of the air inlet duct 204 and the air outlet duct 205 is 0.8 - 2 mm, the depth is 0.2 - 0.3 mm, and the length is 5 - 15 mm.

[0049] In this embodiment, the plurality of air inlet ducts 204 and the air outlet ducts 205 are evenly distributed in a fan shape on the plate body 1 according to the shapes of the air inlet 101 and the air outlet 102 of the plate. The outlet end of each air inlet duct 204 corresponds to the inlet end of the first-stage diversion flow channel 301 of the air inlet distribution area 201. Correspondingly, the outlet end of each first-stage diversion flow channel 301 of the air outlet distribution area 203 corresponds to the inlet end of the air outlet duct 205. The width of the air inlet duct 204 and the air outlet duct 205 can be designed as the following widths, for example: 0.8 mm, 1 mm, 1.2 mm, 1.4 mm, 1.5 mm, 1.7 mm, 1.8 mm, or 2.0 mm, etc., but is not limited to the listed values, and other unlisted values within the above numerical range are equally applicable; the depth of the air inlet duct 204 and the air outlet duct 205 can be designed as the following depths, for example: 0.2 mm, 0.21 mm, 0.22 mm, 0.23 mm, 0.24 mm, 0.25 mm, 0.26 mm, 0.27 mm, 0.28 mm, 0.29 mm, or 0.3 mm, etc., but is not limited to the listed values, and other unlisted values within the above numerical range are equally applicable; the length of the air inlet duct 204 can be designed as the following values, for example: 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, or 15 mm, but is not limited to the listed values, and other unlisted values within the above numerical range are equally applicable.

[0050] In an exemplary embodiment of the present application, the air inlet distribution area 201 and the air outlet distribution area 203 each include a plurality of hierarchical guide structures 3 and branch guide structures 4 arranged side by side, the hierarchical guide structure 3 includes at least a primary guide channel 301 and a secondary guide channel 302, and the branch guide structure 4 includes at least a first branch structure 401 and a second branch structure 402; the first branch structure 401 is used to divide the secondary guide channel 302 into a first branch channel 5 and a second branch channel 6, and the second branch structure 402 is used to divert the first branch channel 5 or the second branch channel 6 into the third branch channel 7 and the fourth branch channel 8. The primary guide channel 301, the secondary guide channel 302, the first branch channel 5, the second branch channel 6, the third branch channel 7 and the fourth branch channel 8 form gas distribution channels in the air inlet distribution area 201 and the air outlet distribution area 203. The sizes of the gas distribution channels arranged side by side on the electrode body 1 are all the same, and the depth of the gas distribution channels is 0.32 to 0.45 mm.

[0051] In this embodiment, a first bending inflection point is formed at the junction of the primary diversion channel 301 and the secondary diversion channel 302, and a second bending inflection point is formed at the junction of the secondary diversion channel 302 and the first branch channel 5 and the second branch channel 6. By designing the angles of the first bending inflection point and the second bending inflection point, the lengths of the gas distribution channels are made substantially the same. By designing the bending angles of the channels, the pressure drop value range of the gas distribution channels is adjusted, so that the gas can be evenly distributed into the reaction flow field area 202. Through the design of the first branch structure 401 and the second branch structure 402, the fluid is re-shunted multiple times, so that the differences caused by different reaction consumption amounts, temperature distributions, and water production amounts in different regions of the gas originally evenly distributed from the air inlet 101 into the air inlet distribution area 201 are restored to uniformity after multiple re-distributions. The depth of the gas distribution channel is 0.32 to 0.45 mm, which is 0.01 to 0.04 mm deeper than the depth of the reaction flow field area 202. The widths of the air inlet transition channel 206 and the air outlet transition channel 207 are 1 to 2 mm, and the depth is the same as that of the distribution channel. The shape of the transition channel is the same as the shape of the duct edge. The depth of the gas distribution channel can be designed as the following depths, for example: 0.32 mm, 0.33 mm, 0.34 mm, 0.35 mm, 0.36 mm, 0.37 mm, 0.38 mm, 0.39 mm, 0.4 mm, 0.41 mm, 0.42 mm, 0.43 mm, 0.44 mm or 0.45 mm, etc., but not limited to the listed values. Other unlisted values within the above numerical range are equally applicable. The depth near the air inlet end of the reaction flow field area 202 can be appropriately adjusted according to the assembly of the single cell. The widths of the air inlet transition channel 206 and the air outlet transition channel 207 can be designed as the following widths, for example: 1 mm, 1.1 mm, 1.2 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.8 mm or 2 mm, etc., but not limited to the listed values. Other unlisted values within the above numerical range are equally applicable.

[0052] In an exemplary embodiment of the present application, the included angle between the primary diversion channel 301 and the long axis of the plate body 1 is α1, and α1 is 0 to 15°; the included angle between the secondary diversion channel 302 and the short axis of the plate body 1 is α2, and α2 is 5 to 20°; the included angle α3 between the air inlet duct 204 and the primary diversion channel 301 is 5 to 20°; at the first branch structure 401, the included angle β1 between the first branch channel 5 and the second branch channel 6 is 55 to 85°; at the second branch structure 402, the included angle β2 between the third branch channel 7 and the fourth branch channel 8 is 15 to 40°; the included angle β3 between the first branch channel 5, the second branch channel 6 and the basic channel 2021 is 5 to 20°.

[0053] In this embodiment, through the angle design of α1 and α2, the bending angles of the first bending inflection point and the second bending inflection point are adjusted, so as to adjust the lengths of the gas distribution channels arranged side by side to be basically the same. And through the angle design of α2, the inlet pressure of the cooling water entering the flow field 2 from the water inlet is reduced, and the pressure drop of the cooling water is reduced. The included angle α3 between the first channel of the air intake duct 204 and the primary diversion channel 301 is 5-20°, and the included angle β3 between the first branch channel 5 and the basic channel 2021 is 5-20°. Through the design of the included angles α3 and β3, the gas transmission can always maintain a flow from top to bottom between the air inlet 101 and the air outlet 102 in the reaction flow field area 202, reduce the pressure drop, and improve the drainage capacity of the reaction flow field 2. α1 includes but is not limited to 0°, 1°, 2°, 3°, 4°, 5°, 6°, 7°, 8°, 9°, 10°, 11°, 12°, 13°, 14° or 15°, etc., but is not limited to the listed values. Other unlisted values within the above value range are equally applicable; α2 includes but is not limited to 5°, 6°, 7°, 8°, 9°, 10°, 11°, 12°, 13°, 14°, 15°, 16°, 17°, 18°, 19° or 20°, etc., but is not limited to the listed values. Other unlisted values within the above value range are equally applicable; β1 includes but is not limited to 55°, 57°, 58°, 59°, 60°, 62°, 64°, 66°, 68°, 70°, 72°, 74°, 76°, 78°, 80°, 82°, 84° or 85°, etc., but is not limited to the listed values. Other unlisted values within the above value range are equally applicable; β2 includes but is not limited to 15°, 16°, 17°, 18°, 19°, 20°, 22°, 24°, 26°, 28°, 30°, 32°, 34°, 36°, 38° or 40°, etc., but is not limited to the listed values. Other unlisted values within the above value range are equally applicable. α3 includes but is not limited to 5°, 6°, 7°, 8°, 9°, 10°, 11°, 12°, 13°, 14°, 16°, 17°, 18°, 19° or 20°, etc., but is not limited to the listed values. Other unlisted values within the above value range are equally applicable; β3 includes but is not limited to 5°, 6°, 7°, 8°, 9°, 10°, 11°, 12°, 13°, 14°, 15°, 16°, 17°, 18°, 19° or 20°, etc., but is not limited to the listed values. Other unlisted values within the above value range are equally applicable.

[0054] In an exemplary embodiment of the present application, the spacing width between two adjacent first-level diversion channels 301 is 1.5 to 2 mm. At 1 / 2h of the cross-section of the first-level diversion channel 301 along the thickness direction of the plate body 1, the width of the first-level diversion channel 301 is 0.8 to 1.5 mm, the ridge width is 0.5 to 0.9 mm, the draft angle is 20 to 30°, the upper R angle is 0.2 to 0.3 mm, the lower R angle is 0.15 to 0.25, and the ratio of the width of the first-level diversion channel 301 to the ridge width is within the range of 1.1:1 to 2.4:1.

[0055] In this embodiment, the channel period of the first-level diversion channel 301 (i.e., the spacing width between two adjacent first-level diversion channels 301) can be 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, or 2 mm, etc., but is not limited to the listed values. Other unlisted values within the above numerical range are equally applicable. At 1 / 2h of the cross-section of the first-level diversion channel 301 along the thickness direction of the plate body 1, the width of the first-level diversion channel 301 can be 0.8 mm, 0.85 mm, 0.9 mm, 0.95 mm, 1.0 mm, 1.05 mm, 1.1 mm, 1.15 mm, 1.2 mm, 1.25 mm, 1.3 mm, 1.35 mm, 1.4 mm, 1.45 mm, or 1.5 mm, etc., but is not limited to the listed values. Other unlisted values within the above numerical range are equally applicable; the ridge width can be 0.5 mm, 0.55 mm, 0.6 mm, 0.65 mm, 0.7 mm, 0.75 mm, 0.8 mm, 0.85 mm, or 0.9 mm, etc., but is not limited to the listed values. Other unlisted values within the above numerical range are equally applicable. The draft angle of the first-level diversion channel 301 can be 20°, 22°, 24°, 25°, 26°, 27°, 28°, 29°, or 30°, etc., but is not limited to the listed values. Other unlisted values within the above numerical range are equally applicable; the upper R angle can be 0.2 mm, 0.22 mm, 0.24 mm, 0.25 mm, 0.26 mm, 0.28 mm, or 0.3 mm, etc., but is not limited to the listed values. Other unlisted values within the above numerical range are equally applicable; the lower R angle can be 0.15 mm, 0.16 mm, 0.18 mm, 0.19 mm, 0.20 mm, 0.22 mm, 0.24 mm, or 0.25 mm, etc., but is not limited to the listed values. Other unlisted values within the above numerical range are equally applicable; the ratio of the channel width to the ridge width of the first-level diversion channel 301 can be 1.1:1, 1.3:1, 1.5:1, 1.7:1, 1.9:1, 2.0:1, 2.1:1, 2.3:1, or 2.4:1, etc., but is not limited to the listed values. Other unlisted values within the above numerical range are equally applicable.

[0056] In an exemplary embodiment of the present application, the spacing width between two adjacent secondary diversion channels 302 is 1.2 to 1.8 mm. At 1 / 2h of the cross-section of the secondary diversion channel 302 along the thickness direction of the plate body 1, the width of the secondary diversion channel 302 is 0.8 to 1.5 mm, the ridge width is 0.45 to 0.8 mm, the draft angle is 20 to 25°, the upper R angle is 0.2 to 0.25 mm, the lower R angle is 0.15 to 0.2, and the ratio of the width of the secondary diversion channel 302 to the ridge width is in the range of 1.5:1 to 3:1.

[0057] In this embodiment, the channel period of the secondary diversion channel 302 (i.e., the spacing width between two adjacent secondary diversion channels 302) can be 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm or 1.8 mm, etc., but is not limited to the listed values. Other unlisted values within the above numerical range are equally applicable. At 1 / 2h of the cross-section of the secondary diversion channel 302 along the thickness direction of the plate body 1, the ridge width can be 0.45 mm, 0.5 mm, 0.55 mm, 0.6 mm, 0.65 mm, 0.7 mm, 0.75 mm or 0.8 mm, etc., but is not limited to the listed values. Other unlisted values within the above numerical range are equally applicable. The draft angle of the secondary diversion channel 302 can be 20°, 21°, 22°, 23°, 24° or 25°, etc., but is not limited to the listed values. Other unlisted values within the above numerical range are equally applicable; the upper R angle can be 0.2 mm, 0.21 mm, 0.22 mm, 0.23 mm, 0.24 mm or 0.25 mm, etc., but is not limited to the listed values. Other unlisted values within the above numerical range are equally applicable; the lower R angle can be 0.15 mm, 0.16 mm, 0.18 mm, 0.19 mm or 0.2 mm, etc., but is not limited to the listed values. Other unlisted values within the above numerical range are equally applicable; the ratio of the channel width to the ridge width of the secondary diversion channel 302 can be 1.5:1, 1.7:1, 1.9:1, 2.1:1, 2.3:1, 2.5:1, 2.7:1, 2.9:1 or 3:1, etc., but is not limited to the listed values. Other unlisted values within the above numerical range are equally applicable.

[0058] In an exemplary embodiment of the present application, the spacing width between the first branch flow channel 5 and the second branch flow channel 6 is 1.9 to 2.4 mm. At 1 / 2h of the cross-section of the first branch flow channel 5 and the second branch flow channel 6 along the thickness direction of the plate body 1, the widths of both the first branch flow channel 5 and the second branch flow channel 6 are 0.55 to 0.9 mm, the ridge width is 1 to 1.85 mm, the draft angle is 20 to 25°, the upper R angle is 0.15 to 0.3 mm, the lower R angle is 0.1 to 0.2 mm, and the ratio of the widths of the first branch flow channel 5 and the second branch flow channel 6 to the ridge width is within the range of 1.7:1 to 3.3:1.

[0059] In this embodiment, the flow channel period of the first branch flow channel 5 and the second branch flow channel 6 can be 1.9 mm, 2.0 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.35 mm or 2.4 mm, etc., but is not limited to the listed values, and other unlisted values within the above value range are equally applicable. At 1 / 2h of the cross-section of the first branch flow channel 5 and the second branch flow channel 6 along the thickness direction of the plate body 1, the flow channel width can be 0.55 mm, 0.6 mm, 0.65 mm, 0.7 mm, 0.75 mm, 0.8 mm, 0.85 mm or 0.9 mm, etc., but is not limited to the listed values, and other unlisted values within the above value range are equally applicable; the ridge width can be 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm or 1.85 mm, etc., but is not limited to the listed values, and other unlisted values within the above value range are equally applicable. The draft angle of the first branch flow channel 5 and the second branch flow channel 6 can be 20°, 21°, 22°, 23°, 24° or 25°, etc., but is not limited to the listed values, and other unlisted values within the above value range are equally applicable; the upper R angle can be 0.15 mm, 0.17 mm, 0.18 mm, 0.2 mm, 0.22 mm, 0.24 mm, 0.25 mm, 0.26 mm, 0.28 mm or 0.3 mm, etc., but is not limited to the listed values, and other unlisted values within the above value range are equally applicable; the lower R angle can be 0.10 mm, 0.12 mm, 0.14 mm, 0.15 mm, 0.16 mm, 0.18 mm, 0.19 mm or 0.2 mm, etc., but is not limited to the listed values, and other unlisted values within the above value range are equally applicable; the ratio of the flow channel width of the first branch flow channel 5 and the second branch flow channel 6 to the ridge width can be 1.7:1, 1.9:1, 2.1:1, 2.3:1, 2.5:1, 2.7:1, 2.9:1, 3:1, 3.1:1 or 3.3:1, etc., but is not limited to the listed values, and other unlisted values within the above value range are equally applicable.

[0060] In an exemplary embodiment of the present application, the period of the basic flow channels 2021 in the reaction flow field region 202 is 0.99 - 1.2 mm (i.e., the interval width between two adjacent basic flow channels 2021 is 0.99 - 1.2 mm), the depth of the straight-flow section 2021a of the basic flow channel 2021 is 0.3 - 0.4 mm, which can effectively improve the gas transmission capacity of the flow channels. The length of the basic flow channel 2021 is 220 - 245 mm, the number of flow channels is 70 - 85, and the ratio of the length to the width of the reaction flow field region 202 is within the range of 2.4:1 to 3.3:1. This can ensure that under the condition of a certain pressure difference to meet the drainage performance, the gas reaction concentrations at the inlet end and the outlet end of the reaction flow field region 202 differ within a reasonable range, so as to improve the uniformity of the gas concentration distribution and the current density distribution of the entire plate of the electrode plate.

[0061] In this embodiment, the period of the basic flow channels 2021 in the reaction flow field region 202 can be 0.99 mm, 1.0 mm, 1.02 m, 1.04 mm, 1.05 mm, 1.07 mm, 1.09 mm, 1.1 m, 1.11 mm, 1.12 m, 1.14 mm, 1.15 mm, 1.17 mm, 1.19 mm or 1.2 mm, etc., but is not limited to the listed values. Other unlisted values within the above numerical range are equally applicable. The depth of the straight-flow section 2021a can be 0.30 mm, 0.31 mm, 0.32 m, 0.33 mm, 0.34 mm, 0.35 mm, 0.36 mm, 0.37 m, 0.38 mm, 0.39 m or 0.40 mm, etc., but is not limited to the listed values. Other unlisted values within the above numerical range are equally applicable. The length of the basic flow channel 2021 can be 220 mm, 223 m, 226 mm, 229 m, 230 mm, 234 mm, 236 mm, 238 mm, 240 mm, 242 mm, 244 mm or 245 m, etc., but is not limited to the listed values. Other unlisted values within the above numerical range are equally applicable. The number of flow channels of the basic flow channel 2021 can be 70, 72, 73, 74, 75, 77, 78, 80, 81, 83, 84 or 85, etc., but is not limited to the listed values. Other unlisted values within the above numerical range are equally applicable. The ratio of the length to the width of the reaction flow field region 202 can be 2.4:1, 2.5:1, 2.6:1, 2.7:1, 2.8:1, 2.9:1, 3.0:1, 3.1:1 or 3.3:1, etc., but is not limited to the listed values. Other unlisted values within the above numerical range are equally applicable.

[0062] In an exemplary embodiment of the present application, the draft angle of the basic flow channel 2021 of the DC section 2021a is 20 to 25°, the upper R angle is 0.15 to 0.3 mm, the lower R angle is 0.1 to 0.2 mm. At 1 / 2h of the cross-section of the DC section 2021a along the thickness direction of the plate body 1, the width of the flow channel is 0.55 to 0.7 mm, the ridge width is 0.4 to 0.5 mm, and the ratio of the flow channel width to the ridge width of the basic flow channel 2021 of the DC section 2021a is within the range of 1.25:1 to 1.75:1. Through the above dimension parameter design, the flow channel has a larger transmission cross-sectional area, smaller transmission under the ridge, improves the gas transmission capacity, and improves the uniformity of gas concentration distribution and current density distribution.

[0063] In this embodiment, the draft angle of the basic flow channel 2021 of the DC section 2021a can be 20°, 21°, 22°, 23°, 24° or 25°, etc., but is not limited to the listed values, and other unlisted values within the above value range are equally applicable; the upper R angle of the basic flow channel 2021 of the DC section 2021a can be 0.15 mm, 0.17 mm, 0.18 mm, 0.2 mm, 0.22 mm, 0.25 m, 0.27 mm, 0.28 m or 0.30 mm, etc., but is not limited to the listed values, and other unlisted values within the above value range are equally applicable; the lower R angle of the basic flow channel 2021 of the DC section 2021a can be 0.1 m, 0.12 mm, 0.15 mm, 0.17 mm or 0.2 mm, etc., but is not limited to the listed values, and other unlisted values within the above value range are equally applicable. The reason for taking the 1 / 2h position of the cross-section as the reference position is that in the flow field 2, this is usually the intermediate position of the flow velocity and the flow channel depth distribution, and is representative of the flow characteristics of the entire flow field 2. By selecting this position as the reference, the change law of the flow channel size and the distribution of the flow velocity can be better understood. In the design, the cross-section of the DC section 2021a along the thickness direction of the plate body 1 is at 1 / 2h, and the width of the basic flow channel 2021 is 0.55 - 0.7 mm, for example, 0.55 mm, 0.56 mm, 0.57 mm, 0.58 mm, 0.59 mm, 0.60 mm, 0.61 mm, 062 mm, 0.63 mm, 0.64 mm, 0.65 mm, 0.66 mm, 0.67 mm, 0.68 mm, 0.69 mm or 0.7 mm, etc., but is not limited to the listed values, and other unlisted values within the above value range are equally applicable. The ridge width of the basic flow channel 2021 of the DC section 2021a is 0.4 - 0.55 mm, for example, 0.4 mm, 0.41 mm, 0.42 mm, 0.43 mm, 0.44 mm, 0.45 mm, 0.46 mm, 0.47 mm, 0.48 mm, 0.49 mm, or 0.5 mm, etc., but is not limited to the listed values, and other unlisted values within the above value range are equally applicable. In the design, the ratio of the flow channel width to the ridge width of the basic flow channel 2021 of the DC section 2021a is in the range of 1.25:1 to 1.75:1, for example, 1.25:1, 1.30:1, 1.35:1, 1.40:1, 1.45:1, 1.50:1, 1.55:1, 1.60:1, 1.65:1, 1.70:1 or 1.75:1, but is not limited to the listed values, and other unlisted values within the above value range are equally applicable.

[0064] In an exemplary embodiment of the present application, the narrowest point of the variable runoff section 2021b can be set at any position of the variable runoff section 2021b. At the narrowest point of the variable runoff section 2021b, both the depth and width of the basic flow channel 2021 are the smallest. The starting end and the ending end of the variable runoff section 2021b are connected to the straight flow section 2021a. From the starting end and the ending end of the variable runoff section 2021b to the narrowest point of the variable runoff section 2021b, the dimensions of the basic flow channel 2021 gradually narrow in terms of depth and width, gradually shrinking to the narrowest point of the variable runoff section 2021b. The depth of the narrowest point of the variable runoff section 2021b is 0.12 - 0.25 mm. At the 1 / 2h position of the cross-section of the variable runoff section 2021b along the thickness direction of the electrode plate body 1, the width of the narrowest point of the variable runoff section 2021b is 0.14 - 0.25 mm.

[0065] In this embodiment, the depth of the narrowest point of the variable runoff section 2021b can be 0.12 mm, 0.13 mm, 0.14 mm, 0.14 mm, 0.15 mm, 0.16 mm, 0.17 mm, 0.18 mm, 0.19 mm, 0.20 mm, 0.21 mm, 0.22 mm, 0.23 mm, 0.24 mm or 0.25 mm, etc., but is not limited to the listed values. Other unlisted values within the above value range are equally applicable; the width of the narrowest point of the variable runoff section 2021b can be 0.14 mm, 0.15 mm, 0.16 mm, 0.17 mm, 0.18 mm, 0.19 mm, 0.20 mm, 0.21 mm, 0.22 mm, 0.23 mm, 0.24 mm or 0.25 mm, etc., but is not limited to the listed values. Other unlisted values within the above value range are equally applicable.

[0066] In an exemplary embodiment of the present application, the extension length of the variable runoff section 2021b along the gas flow direction of the basic flow channel 2021 is 4 - 8 mm. Each basic flow channel 2021 includes 6 - 10 variable runoff sections 2021b. The 6 - 10 variable runoff sections 2021b gradually become denser along the gas flow direction and are arranged in an arithmetic progression, with a distance tolerance of 1 - 5 mm.

[0067] In this embodiment, the length of the variable runoff section 2021b includes, but is not limited to, 4mm, 4.2mm, 4.4mm, 4.6mm, 4.8mm, 5mm, 5.2mm, 5.4mm, 5.6mm, 5.8mm, 6mm, 6.2mm, 6.4mm, 6.6mm, 6.8mm, 7mm, 7.2mm, 7.4mm, 7.6mm, 7.8mm, 8mm, etc.; the variable runoff section 2021b in the basic flow channel 2021 will also cause eddy currents, which consume energy and cause local pressure drops. The length of the basic flow channel 2021 is fixed. The more variable runoff sections 2021b are provided on the basic flow channel 2021, the greater the pressure drop in the reaction flow field area 202. Therefore, whether the design quantity range of the variable runoff section 2021b is reasonable is also a key factor in designing the pressure drop, which can effectively enhance the gas transmission capacity and the drainage capacity of the flow channel, and improve the stack current density. The number of variable runoff sections 2021b provided on the basic flow channel 2021 in this application includes, but is not limited to, 6, 7, 8, 9, or 10, etc. The above-listed quantities can keep the pressure drop in the reaction flow field area 202 within a reasonable range. By arranging the variable runoff sections 2021b in an arithmetic progression along the gas flow direction and gradually densifying towards the end near the gas outlet 102, the tolerance range includes, but is not limited to, 1mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, 2mm, 2.2mm, 2.4mm, 2.6mm, 2.8mm, 3mm, 3.2mm, 3.4mm, 3.6mm, 3.8mm, 4mm, 4.2mm, 4.4mm, 4.6mm, 4.8mm, or 5mm, etc., which can effectively enhance the drainage capacity in the second half of the basic flow channel 2021 and improve the uniformity of gas concentration distribution and current density distribution of the entire plate.

[0068] In an exemplary embodiment of this application, the length of the DC section 2021a before the first variable runoff section 2021b of the basic flow channel 2021 is 10 - 70mm, and the length of the DC section 2021a after the last variable runoff section 2021b of the basic flow channel 2021 is 1 - 10mm. According to the reaction conditions at different positions in the reaction area, different drainage and gas distribution capabilities can be matched to the reaction area; the variable runoff sections 2021b on adjacent two basic flow channels 2021 are arranged alternately, and the interval distance of the alternate arrangement is 0.5 - 2.5mm, that is, at the midpoint between two adjacent variable runoff sections 2021b on any basic DC channel, there is also a variable runoff section 2021b at the corresponding position on the adjacent basic flow channel 2021, and corresponding to the midpoint of this variable runoff section 2021b, which can promote gas transmission between adjacent basic flow channels 2021 and improve the gas distribution uniformity and current density.

[0069] In this embodiment, the length of the direct current section 2021a before the first variable diameter flow section 2021b of the basic flow channel 2021 can be 10mm, 15mm, 20mm, 25mm, 30mm, 35mm, 40mm, 45mm, 50mm, 55mm, 60mm, 65m or 70mm, etc., but is not limited to the listed values, and other values not listed within the above numerical range are equally applicable; the length of the direct current section 2021a after the last variable diameter flow section 2021b of the basic flow channel 2021 can be 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm or 10mm, etc., but is not limited to the listed values, and other values not listed within the above numerical range are equally applicable.

[0070] The present application also proposes a fuel cell single cell structure, including a membrane electrode, an anode plate and the fuel cell plate structure as described above, the fuel cell plate structure, the membrane electrode and the anode plate are stacked in sequence to form a fuel cell single cell; or includes a membrane electrode and two fuel cell plate structures as described above, the fuel cell single cell is formed by stacking the fuel cell plate structure, the membrane electrode and the fuel cell plate structure in sequence.

[0071] The present application also proposes a fuel cell stack, comprising a plurality of fuel cell single cell structures as described above, wherein the plurality of fuel cell single cell structures are stacked in sequence to form a fuel cell stack.

[0072] The present application also provides a vehicle, comprising the fuel cell stack as described above.

[0073] The technical solution of the present invention is further illustrated by way of comparative examples below.

[0074] Example 1

[0075] The flow field 2 shown in the present application is arranged on the side of the cathode plate of the fuel cell facing the membrane electrode in the thickness direction, and at least has an inlet distribution area 201 and a reaction flow field area 202 from the air inlet 101 to the air outlet 102. The side of the cathode plate facing away from the membrane electrode in the thickness direction and the side of the anode plate facing away from the membrane electrode in the thickness direction form a cooling flow field 2;

[0076] The cathode plate is provided with an air inlet duct 204, an air inlet transition channel 206, an air inlet distribution area 201, a reaction flow field area 202, an air outlet distribution area 203, an air outlet transition channel 207 and an air outlet duct 205 in sequence from the air inlet 101a to the air outlet 102a;

[0077] The graded flow guide structure 3 is divided into a primary flow guide channel 301 and a secondary flow guide channel 302, wherein the angle α1 between the primary flow guide channel 301 and the long axis of the plate body 1 (normal to the air inlet 101) is 16°, and the angle α2 between the secondary flow guide channel 302 and the short axis of the plate body 1 is 0°. The angle β2 between the third branch flow channel 7 and the fourth branch flow channel 8 is 25°; the depth of the gas distribution flow channel is 0.4 mm;

[0078] The reaction flow field area 202 includes 70 basic flow channels 2021 arranged side by side along the short axis direction of the electrode body 1, the basic flow channel 2021 is 240 mm long, and the basic flow channel 2021 includes a plurality of straight flow sections 2021a and a plurality of variable diameter flow sections 2021b. The depth of the straight flow section 2021a basic flow channel 2021 is 0.37 mm, the width of the cross section of the straight flow section 2021a along the thickness direction of the electrode body 1 at 1 / 2h is 0.72 mm, and the ridge width at 1 / 2h of the cross section of the straight flow section 2021a is 0.48 mm;

[0079] The type and size of each variable diameter flow section 2021b are the same; the depth of the variable diameter flow section 2021b at the narrowest point is 0.16mm, the width of the variable diameter flow section 2021b at the narrowest cross section 1 / 2h is 0.2mm, and the length of the variable diameter flow section 2021b is 8mm. Among them, the number of variable diameter flow sections 2021b on the basic flow channel 2021 is 8, and the variable diameter flow sections 2021b are arranged according to an arithmetic progression. The distance tolerance of the variable diameter flow sections 2021b is 2mm, and the variable diameter flow sections 2021b on adjacent basic flow channels 2021 are staggered with each other.

[0080] Example 2

[0081] The flow field 2 shown in the present application is arranged on the side of the cathode plate of the fuel cell facing the membrane electrode in the thickness direction, and at least has an inlet distribution area 201 and a reaction flow field area 202 from the air inlet 101 to the air outlet 102. The side of the cathode plate facing away from the membrane electrode in the thickness direction and the side of the anode plate facing away from the membrane electrode in the thickness direction form a cooling flow field 2.

[0082] The cathode plate is provided with an air inlet duct 204, an air inlet transition channel 206, an air inlet distribution area 201, a reaction flow field area 202, an air outlet distribution area 203, an air outlet transition channel 207 and an air outlet duct 205 in sequence from the air inlet 101a to the air outlet 102a;

[0083] The graded flow guide structure 3 is divided into a primary flow guide channel 301 and a secondary flow guide channel 302, wherein the bending angle α1 between the primary flow guide channel 301 and the inlet normal direction is 8°, and the angle α2 between the secondary flow guide channel 302 and the short axis of the plate body 1 is 6°. The angle β2 between the third branch flow channel 7 and the fourth branch flow channel 8 is 25°, the depth of the gas distribution flow channel is 0.4mm, and the depth close to the inlet end of the reaction flow field area 202 is 0.37mm;

[0084] The reaction flow field area 202 includes 70 basic flow channels 2021 arranged side by side, the basic flow channels 2021 are 240 mm long, and the basic flow channels 2021 are all straight flow channels. The basic flow channels 2021 include multiple straight flow sections 2021a and multiple variable diameter flow sections 2021b; the flow channel depth of the straight flow section 2021a is 0.36 mm, the width at 1 / 2h of the cross section of the straight flow section 2021a is 0.72 mm, and the ridge width at 1 / 2h of the cross section of the straight flow section 2021a is 0.48 mm;

[0085] The type and size of each variable diameter flow section 2021b are the same; the depth of the narrowest part of the variable diameter flow section 2021b is 0.16mm, the width of the narrowest cross section 1 / 2h of the variable diameter flow section 2021b is 0.2mm, and the length of the variable diameter flow section 2021b is 8mm. Among them, the number of variable diameter flow sections 2021b on the basic flow channel 2021 is 8, arranged according to an arithmetic progression, the distance tolerance range of the variable diameter flow sections 2021b is 2mm, and the variable diameter flow sections 2021b on adjacent basic flow channels 2021 are staggered with each other.

[0086] Comparative Example 1

[0087] The fuel cell plate structure is arranged on the side of the cathode plate facing the membrane electrode, and has at least an inlet distribution area 201 and a reaction flow field area 202 from the air inlet 101 to the air outlet 102. The side of the cathode plate facing away from the membrane electrode along the thickness direction and the side of the anode plate facing away from the membrane electrode along the thickness direction form a cooling flow field 2.

[0088] The cathode plate is provided with an air inlet duct 204, an air inlet transition channel 206, an air inlet distribution area 201, a reaction flow field area 202, an air outlet distribution area 203, an air outlet transition channel 207 and an air outlet duct 205 in sequence from the air inlet 101a to the air outlet 102a;

[0089] The graded flow guide structure 3 is divided into a primary flow guide channel 301 and a secondary flow guide channel 302, wherein the bending angle α1 between the primary flow guide channel 301 and the inlet normal direction is 8°, and the angle α2 between the secondary flow guide channel 302 and the short axis of the plate body 1 is 6°. The angle β2 between the third branch flow channel 7 and the fourth branch flow channel 8 is 25°, the depth of the gas distribution flow channel is 0.4mm, and the depth close to the inlet end of the reaction flow field area 202 is 0.37mm;

[0090] The reaction flow field area 202 includes a plurality of basic flow channels 2021 arranged side by side, and the basic flow channels 2021 include a plurality of straight flow sections 2021a and a multi-end variable diameter flow section 2021b; the flow channel depth value at the straight flow section 2021a is 0.37mm, the width at 1 / 2h of the cross section of the straight flow section 2021a is 0.72mm, and the ridge width at 1 / 2h of the cross section of the straight flow section 2021a is 0.48mm;

[0091] The type and size of each variable diameter flow section 2021b are the same; the depth of the narrowest part of the variable diameter flow section 2021b is 0.16mm, the width of the narrowest cross section 1 / 2h of the variable diameter flow section 2021b is 0.2mm, and the length of the variable diameter flow section 2021b is 8mm. Among them, the number of variable diameter flow sections 2021b on the basic flow channel 2021 is 10, arranged according to an arithmetic progression, the distance tolerance range of the variable diameter flow sections 2021b is 1mm, and the variable diameter flow sections 2021b on adjacent basic flow channels 2021 are staggered with each other.

[0092] Comparative Example 2

[0093] The fuel cell plate structure is arranged on the side of the cathode plate facing the membrane electrode, and has at least an inlet distribution area 201 and a reaction flow field area 202 from the air inlet 101 to the air outlet 102. The side of the cathode plate facing away from the membrane electrode along the thickness direction and the side of the anode plate facing away from the membrane electrode along the thickness direction form a cooling flow field 2.

[0094] The cathode plate is provided with an air inlet duct 204, an air inlet transition channel 206, an air inlet distribution area 201, a reaction flow field area 202, an air outlet distribution area 203, an air outlet transition channel 207 and an air outlet duct 205 in sequence from the air inlet 101a to the air outlet 102a;

[0095] The graded flow guide structure 3 is divided into a primary flow guide channel 301 and a secondary flow guide channel 302, wherein the bending angle α1 between the primary flow guide channel 301 and the inlet normal direction is 8°, and the angle α2 between the secondary flow guide channel 302 and the short axis of the plate body 1 is 6°. The angle β2 between the third branch flow channel 7 and the fourth branch flow channel 8 is 25°, the depth of the gas distribution flow channel is 0.4mm, and the depth close to the inlet end of the reaction flow field area 202 is 0.37mm;

[0096] The reaction flow field area 202 includes a plurality of basic flow channels 2021 arranged side by side, and the basic flow channels 2021 include a plurality of straight flow sections 2021a and a plurality of variable diameter flow sections 2021b; the flow channel depth of the straight flow section 2021a is 0.37 mm, the width at 1 / 2h of the cross section of the straight flow section 2021a is 0.72 mm, and the ridge width at 1 / 2h of the cross section of the straight flow section 2021a is 0.48 mm;

[0097] The type and size of each variable diameter flow section 2021b are the same; the depth of the narrowest part of the variable diameter flow section 2021b is 0.16mm, the width of the narrowest cross section 1 / 2h of the variable diameter flow section 2021b is 0.46mm, and the length of the variable diameter flow section 2021b is 8mm. Among them, the number of variable diameter flow sections 2021b on the basic flow channel 2021 is 10, arranged according to an arithmetic progression, the distance tolerance range of the variable diameter flow sections 2021b is 1mm, and the variable diameter flow sections 2021b on adjacent basic flow channels 2021 are staggered with each other.

[0098] Comparative Example 3

[0099] The fuel cell plate structure is arranged on the side of the cathode plate facing the membrane electrode, and has at least an inlet distribution area 201 and a reaction flow field area 202 from the air inlet 101 to the air outlet 102. The side of the cathode plate facing away from the membrane electrode along the thickness direction and the side of the anode plate facing away from the membrane electrode along the thickness direction form a cooling flow field 2.

[0100] The cathode plate is provided with an air inlet duct 204, an air inlet transition channel 206, an air inlet distribution area 201, a reaction flow field area 202, an air outlet distribution area 203, an air outlet transition channel 207 and an air outlet duct 205 in sequence from the air inlet 101a to the air outlet 102a;

[0101] The graded flow guide structure 3 is divided into a primary flow guide channel 301 and a secondary flow guide channel 302, wherein the bending angle α1 between the primary flow guide channel 301 and the inlet normal direction is 8°, and the angle α2 between the secondary flow guide channel 302 and the short axis of the plate body 1 is 6°. The angle β2 between the third branch flow channel 7 and the fourth branch flow channel 8 is 25°, the depth of the gas distribution flow channel is 0.4mm, and the depth close to the inlet end of the reaction flow field area 202 is 0.37mm;

[0102] The reaction flow field area 202 includes a plurality of basic flow channels 2021 arranged side by side, and the basic flow channels 2021 are all straight flow channels, and the basic flow channels 2021 include a plurality of straight flow sections 2021a and a plurality of variable diameter flow sections 2021b; the flow channel depth value of the straight flow section 2021a is 0.37mm, the width at 1 / 2h of the cross section of the straight flow section 2021a is 0.72mm, and the ridge width at 1 / 2h of the cross section of the straight flow section 2021a is 0.48mm;

[0103] Each variable runoff section 2021b has the same type and size; the depth at the narrowest part of the variable runoff section 2021b is 0.31 mm, the width at 1 / 2h of the cross-section at the narrowest part of the variable runoff section 2021b is 0.47 mm, and the length of the variable runoff section 2021b is 8 mm. Among them, the number of variable runoff sections 2021b on the basic flow channel 2021 is 10, arranged in an arithmetic progression, the distance tolerance range of the variable runoff section 2021b is 1 mm, and the variable runoff sections 2021b on adjacent basic flow channels 2021 are staggered with each other.

[0104] Table 1

[0105]

[0106] It can be seen from Table 1 that:

[0107] Through the two structural designs of the hierarchical diversion structure 3 and the branch diversion structure 4 in this application, the reaction gas can be evenly distributed in each flow channel when entering the flow field 2 from the common pipeline air inlet 101, so as to make the electrochemical reaction in the active area of the MEA (membrane electrode) uniform. At the same time, the water chamber distribution area diverts the coolant, so that the flow rate of the coolant entering each flow channel of the cooling flow field 2 is uniform, achieving uniform heat dissipation. In Example 2, by adjusting the bending angle α1 between the first-stage diversion flow channel 301 and the normal direction of the inlet and the included angle α2 between the second-stage diversion flow channel 302 and the short axis of the plate body 1, on the one hand, the phenomenon of uneven gas distribution when the gas enters the reaction flow field area 202 from the inlet end can be improved, and the pressure difference between the inlet and outlet of the water chamber can be improved to a great extent.

[0108] Compared with Comparative Example 1, in Example 2, the types and sizes of the air inlet distribution area 201, the direct current section 2021a, the variable runoff section 2021b, and the air outlet distribution area 203 are the same, but the number of variable runoff sections 2021b is reduced. Since the variable runoff section 2021b in the basic flow channel 2021 will also cause eddy currents, which consume energy and cause local pressure drops. The length of the basic flow channel 2021 is fixed. The more the number of variable runoff sections 2021b, the greater the pressure drop in the reaction flow field area 202, but the electrical properties of the reaction flow field area 202 are not very different. Therefore, reasonably adjusting the number of variable runoff sections 2021b is more conducive to controlling the pressure drop value.

[0109] Compared with Comparative Example 2, in Comparative Example 1, since the width of the basic flow channel 2021 becomes smaller at the variable runoff section 2021b and the cross-sectional area suddenly shrinks, under the action of the local pressure gradient, eddy currents occur near the variable runoff section 2021b, especially behind. These eddy currents greatly promote the mixing of gas in the basic flow channel 2021, making the oxygen partial pressure distribution more uniform.

[0110] Compared with Comparative Example 3, the smaller the depth of the variable runoff section 2021b, the smaller the mass transfer resistance in the basic flow channel 2021. This variable runoff section 2021b increases the local gas velocity and local resistance. With the sudden increase in the local pressure drop at the variable runoff section 2021b, a part of the reaction gas is forced to flow into the GDL (gas diffusion layer), thereby enhancing the mass transfer in the GDL (gas diffusion layer).

[0111] The above embodiments are only preferred embodiments given to fully illustrate the present invention, and the protection scope of the present invention is not limited thereto. Equivalent substitutions or transformations made by those skilled in the art on the basis of the present invention are within the protection scope of the present invention.

Claims

1. A fuel cell plate structure, characterized in that, Comprising: A plate body, with an air inlet and an air outlet respectively provided at both ends of the plate body along the length direction; A flow field, arranged on the plate body and located between the air inlet and the air outlet, and the flow field is respectively communicated with the air inlet and the air outlet; The flow field at least includes an air inlet duct, an air inlet distribution area and a reaction flow field area arranged in sequence along the length direction of the plate body. The air inlet duct is used to introduce gas from the air inlet into the air inlet distribution area, and the air inlet distribution area is used to make the gas uniformly flow into the reaction flow field area; The reaction flow field area includes a plurality of basic flow channels arranged side by side along the width direction of the plate body. The basic flow channels include a plurality of straight flow segments and a plurality of variable-diameter flow segments arranged at intervals along the length direction of the plate body. The variable-diameter flow segments on two adjacent basic flow channels are staggered along the length direction of the plate body, and the plurality of variable-diameter flow segments on the basic flow channels are arranged gradually densely along the gas flow direction; The flow field further includes an air outlet distribution area and an air outlet duct. The air outlet distribution area is arranged on the plate body, and the air outlet distribution area is symmetrically arranged with the air inlet distribution area about the center of the reaction flow field area. The air outlet distribution area is used to converge the gas discharged from the reaction flow field area into the air outlet duct, and the air outlet duct is used to guide the gas from the air outlet distribution area to the air outlet for discharge; A plurality of the air inlet ducts are arranged between the air inlet and the air inlet distribution area, and a plurality of the air outlet ducts are arranged between the air outlet and the air outlet distribution area. The plurality of air inlet ducts and the plurality of air outlet ducts are both arranged in a fan shape along the width direction of the plate body; the width of the air inlet duct and the air outlet duct is 0.8 - 2 mm, the depth is 0.2 - 0.3 mm, and the length is 5 - 15 mm; Both the air inlet distribution area and the air outlet distribution area include a plurality of hierarchical diversion structures and branch diversion structures arranged side by side. The hierarchical diversion structure at least includes a primary diversion flow channel and a secondary diversion flow channel, and the branch diversion structure at least includes a first branch structure and a second branch structure; the first branch structure is used to divide the secondary diversion flow channel into a first branch flow channel and a second branch flow channel, and the second branch structure is used to divide the first branch flow channel or the second branch flow channel into a third branch flow channel and a fourth branch flow channel. The primary diversion flow channel, the secondary diversion flow channel, the first branch flow channel, the second branch flow channel, the third branch flow channel and the fourth branch flow channel form a gas distribution flow channel in the air inlet distribution area and the air outlet distribution area. The sizes of the gas distribution flow channels arranged side by side on the plate body are the same, and the depth of the gas distribution flow channel is 0.32 - 0.45 mm.

2. The fuel cell plate structure according to claim 1, characterized in that: An air inlet transition channel is arranged between the air inlet distribution area and the air inlet duct, and an air outlet transition channel is arranged between the air outlet distribution area and the air outlet duct. The width of the air inlet transition channel and the air outlet transition channel is 1 - 2 mm, and the depth is 0.32 - 0.45 mm.

3. The fuel cell plate structure according to claim 1, wherein: The included angle between the first-stage diversion channel and the long axis of the plate body is α1, where α1 ranges from 0 to 15°; the included angle between the second-stage diversion channel and the short axis of the plate body is α2, where α2 ranges from 5 to 20°; the included angle α3 between the air intake duct and the first-stage diversion channel is 5 to 20°. At the first branch structure, the included angle β1 between the first branch channel and the second branch channel is 55 to 85°; at the second branch structure, the included angle β2 between the third branch channel and the fourth branch channel is 15 to 40°; the included angle β3 between the first branch channel, the second branch channel and the basic channel is 5 to 20°.

4. The fuel cell plate structure according to claim 1, wherein: The spacing width between two adjacent first-stage diversion channels is 1.5 to 2 mm. At the 1 / 2h position of the cross-section of the first-stage diversion channel along the thickness direction of the plate body, the width of the first-stage diversion channel is 0.8 to 1.5 mm, the ridge width is 0.5 to 0.9 mm, the draft angle is 20 to 30°, the upper R angle is 0.2 to 0.3 mm, the lower R angle is 0.15 to 0.25, and the ratio of the width of the first-stage diversion channel to the ridge width is 1.1:1 to 2.4:

1.

5. The fuel cell plate structure according to claim 1, characterized in that: The spacing width between two adjacent second-stage diversion channels is 1.2 to 1.8 mm. At the 1 / 2h position of the cross-section of the second-stage diversion channel along the thickness direction of the plate body, the width of the second-stage diversion channel is 0.8 to 1.5 mm, the ridge width is 0.45 to 0.8 mm, the draft angle is 20 to 25°, the upper R angle is 0.2 to 0.25 mm, the lower R angle is 0.15 to 0.2, and the ratio of the width of the second-stage diversion channel to the ridge width is 1.5:1 to 3:

1.

6. The fuel cell plate structure according to claim 1, characterized in that: The spacing width between the first branch channel and the second branch channel is 1.9 to 2.4 mm. At the 1 / 2h position of the cross-section of the first branch channel and the second branch channel along the thickness direction of the plate body, the widths of the first branch channel and the second branch channel are both 0.55 to 0.9 mm, the ridge width is 1 to 1.85 mm, the draft angle is 20 to 25°, the upper R angle is 0.15 - 0.3 mm, the lower R angle is 0.1 to 0.2 mm, and the ratios of the widths of the first branch channel and the second branch channel to the ridge width are both 1.7:1 to 3.3:

1.

7. The fuel cell plate structure according to claim 1, wherein: The spacing width between two adjacent basic channels is 0.99 to 1.2 mm, the length of the basic channel is 220 to 245 mm, the number of the basic channels is 70 to 85, and the ratio of the length to the width of the reaction flow field area is 2.4:1 to 3.3:

1.

8. The fuel cell plate structure according to claim 7, wherein: Located in the DC section, the depth of the basic flow channel is 0.3 - 0.4 mm. The cross-section of the DC section along the thickness direction of the plate body is at 1 / 2h. The width of the basic flow channel is 0.55 - 0.7 mm, the ridge width is 0.4 - 0.5 mm, the draft angle of the basic flow channel is 20 - 25°, the upper R angle is 0.15 - 0.3 mm, and the lower R angle is 0.1 - 0.2 mm. The ratio of the width of the basic flow channel to the ridge width is 1.25:1 - 1.75:

1.

9. The fuel cell plate structure according to claim 1, characterized in that: The variable flow section has a narrowest point. The starting end and the ending end of the variable flow section are both connected to the DC section. From the starting end and the ending end of the variable flow section to the narrowest point, the depth and width of the basic flow channel gradually decrease. Located at the narrowest point of the variable flow section, the depth of the basic flow channel is 0.12 - 0.25 mm. The cross-section of the variable flow section along the thickness direction of the plate body is at 1 / 2h. The width at the narrowest point of the variable flow section is 0.14 - 0.25 mm.

10. The fuel cell plate structure according to claim 9, wherein: The variable flow section extends 4 - 8 mm in the gas flow direction. Each basic flow channel includes 6 - 10 variable flow sections. The 6 - 10 variable flow sections gradually become denser in the gas flow direction and are arranged in an arithmetic progression, with a distance tolerance of 1 - 5 mm.

11. The fuel cell plate structure according to claim 10, characterized in that: Along the gas flow direction, the length of the DC section before the first variable flow section is 10 - 70 mm, and the length of the DC section after the last variable flow section is 1 - 10 mm. The variable flow sections on adjacent basic flow channels in the reaction flow field area are arranged alternately, and the alternating interval distance is 0.5 - 2.5 mm.

12. A fuel cell single cell structure, characterized in that: It includes a membrane electrode, an anode plate, and the fuel cell plate structure according to any one of claims 1 - 11. The fuel cell plate structure, the membrane electrode, and the anode plate are stacked in sequence to form the fuel cell single cell; Or it includes a membrane electrode and two fuel cell plate structures according to any one of claims 1 - 11. The fuel cell single cell is formed by stacking the fuel cell plate structure, the membrane electrode, and the fuel cell plate structure in sequence.

13. A fuel cell stack, characterized in that: It includes a plurality of fuel cell single cell structures according to claim 12. The plurality of fuel cell single cell structures are stacked in sequence to form the fuel cell stack.

14. A vehicle, characterized in that: It includes the fuel cell stack according to claim 13.

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