Air-cooled fuel cell and bipolar plate

Abstract

The invention discloses an air-cooled fuel cell bipolar plate which comprises a plate body which is rectangular on the whole, and a cathode side plate and an anode side plate are respectively arranged on two sides of the plate body in the thickness direction; an air hole through which hydrogen enters or is discharged is formed in the plate body in a penetrating manner; an L-shaped hydrogen flow channel is formed in the anode side plate and is arranged in a central symmetry manner along the direction of the other diagonal line of the plate body; a transverse runner arranged in the width direction of the plate body is arranged between the two groups of hydrogen runners, and the transverse runner is sequentially connected with the corresponding hydrogen runners in the length direction of the plate body; and a gap is reserved between the side wall of each transverse flow channel and the side wall of the corresponding hydrogen flow channel, so that a turbulent flow channel is formed between the multiple hydrogen flow channels and the multiple transverse flow channels, and the two groups of hydrogen flow channels are communicated with the corresponding air holes respectively, so that an anode flow channel allowing hydrogen to enter and be discharged is formed. In conclusion, the reactor has the advantages of controlling pressure intensity and flow velocity balance, improving reaction efficiency and the like.

Description

Technical Field

[0001] This invention relates to the field of fuel cell technology, and in particular to an air-cooled fuel cell and a bipolar plate. Background Technology

[0002] Bipolar plates are a core component of fuel cells, primarily functioning to support the MEA (Mechanical Electrode Assembly), provide hydrogen and oxygen channels and separate hydrogen and oxygen, collect electrons, and conduct heat. The flow channels designed and fabricated on the bipolar plates ensure a uniform distribution of the reaction medium throughout the entire electrode, and evenly distribute the fluid to the reaction layer of the electrode for electrochemical reactions.

[0003] In actual processing and application, bipolar plates need to balance the utilization rate of the plate surface and the supporting function. Theoretically, the larger the contact area between the flow channel and the proton exchange membrane, the higher the utilization rate and the better the performance of the fuel cell. However, in the actual assembly and processing of fuel cells, due to the lack of support in parts with large contact areas, the proton exchange membrane is easily damaged. In addition, while ensuring the utilization rate and supporting function, the flow channels should also ensure that the lengths between each flow channel are the same to avoid uneven power density of the fuel cell due to uneven gas flow distribution, which can easily cause damage to the fuel cell.

[0004] To address the aforementioned technical problems, Chinese patent literature discloses an air-cooled fuel cell bipolar plate, patent application number 2023226245391. This patent uses S-shaped flow channels of equal length on the anode side of the bipolar plate and straight flow channels on the cathode side to ensure that all flow channels are of equal length while maximizing the utilization of the bipolar plate area. However, in actual use, excessive gas pressure difference between adjacent flow channels can occur due to flooding or other reasons, or uneven flow rates can lead to localized starvation or enrichment of the membrane electrode assembly (MEA), resulting in uneven hydrogen reaction on the MEA and a decrease in fuel cell efficiency. Therefore, to solve the above technical problems, this invention provides a fuel cell bipolar plate that can enhance mass transfer, control pressure and flow rate balance, and improve reaction efficiency. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the technical problem to be solved by the present invention is: how to provide a fuel cell bipolar plate and fuel cell that can enhance mass transfer and control pressure and flow rate balance, and improve reaction efficiency.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] An air-cooled fuel cell bipolar plate includes a rectangular plate body, with a cathode side plate and an anode side plate on both sides in the thickness direction; the plate body is provided with through holes for hydrogen to enter or exit, and is symmetrically arranged along its diagonal direction, and the holes are fitted with a flow splitting component on the anode side plate;

[0008] The anode side plate has multiple L-shaped hydrogen flow channels, which are symmetrically arranged along the other diagonal direction of the plate. Between the two sets of hydrogen flow channels, there are transverse flow channels arranged along the width direction of the plate and multiple transverse flow channels arranged along the length direction of the plate. The transverse flow channels are sequentially connected to the corresponding hydrogen flow channels along the length direction of the plate. The sidewall of each transverse flow channel is separated from the sidewall of the corresponding hydrogen flow channel, so that a turbulence channel is formed between the multiple hydrogen flow channels and the multiple transverse flow channels. The two sets of hydrogen flow channels are respectively connected to the corresponding gas holes, so that the gas holes, hydrogen flow channels and transverse flow channels form an overall S-shaped anode flow channel for hydrogen to enter and exit.

[0009] The above structure, with its centrally symmetrical hydrogen flow channels and transverse flow channels along the width, ensures that the length of each anode flow channel on the anode side plate remains consistent. This helps stabilize hydrogen pressure and prevents excessive gas pressure loss due to excessively long single flow channels, which could lead to low gas concentration in the latter half of the flow channel, reduced current density, and flooding. Furthermore, the centrally symmetrically arranged vents at both diagonal ends save space and improve the space utilization of the bipolar plate compared to the traditional method of vents occupying the entire width of the bipolar plate at both ends along the length. The overall S-shaped arrangement of the anode flow channels facilitates the formation of negative pressure within the channels, expelling liquid water and gas. Turbulence channels are provided between the hydrogen flow channels, ensuring interconnectivity and reducing localized "starvation" or "enrichment" caused by uneven flow rates. This improves the uniformity of current density distribution, enhances gas diffusion into the GDL, and increases reaction efficiency.

[0010] Furthermore, the cathode side plate is provided with an oxygen channel for oxygen flow, the oxygen channel including a first oxygen flow channel and a second oxygen flow channel disposed between the two air holes; multiple first oxygen flow channels and second oxygen flow channels are evenly distributed along the length direction of the plate, wherein two sets of first oxygen flow channels are disposed along the width direction of the plate and are centrally symmetrically arranged; the second oxygen flow channels are sequentially connected to the corresponding first oxygen flow channels along the length direction of the plate, so as to form an overall Z-shaped oxygen channel on the cathode side plate; a gap is left between the sidewall of the first oxygen flow channel and the sidewall of the second oxygen flow channel, so that an open channel is formed between the multiple oxygen channels.

[0011] In this way, the diagonal center design of the pores saves board space. The oxygen channel design can increase the number of existing oxygen channels, improve heat dissipation, and the parallel Z-shaped oxygen channel design increases the contact area between air and heat dissipation fins, improving heat dissipation efficiency. At the same time, it increases the contact area between air in each flow channel and the cathode surface of the membrane electrode during use, greatly improving oxygen supply efficiency. The oxygen channel is equipped with an open channel to increase air turbulence, increase the rate at which oxygen passes through the diffusion layer, and draw the liquid water under the ridge into the main flow channel to meet the drainage requirements of the flow channel.

[0012] Furthermore, the width of the turbulence channel is less than or equal to the width of the hydrogen flow channel, and the width of the turbulence channel is greater than half of the hydrogen flow channel; the width of the open channel is equal to the width of the oxygen channel.

[0013] In this way, the turbulence channel, which is narrower than the hydrogen flow channel, can prioritize the flow of hydrogen within its respective hydrogen flow channel. Furthermore, when other hydrogen channels become flooded or blocked, it can create significant hydrogen pressure to clear the flow channels. Additionally, since the turbulence channel is constantly filled with hydrogen during fuel cell operation, it can lead to localized hydrogen enrichment. If the bipolar plate is made of metal, this could result in a higher risk of hydrogen embrittlement, reducing the lifespan and mechanical strength of the bipolar plate. Localized hydrogen enrichment can also cause the prototype to dry out, leading to excessive localized water loss from the proton exchange membrane. This can cause an imbalance in fuel cell performance at both ends of the turbulence channel, increasing the risk of burnout.

[0014] Furthermore, the pores are arranged in isosceles right triangles, and recesses are formed on the cathode side plate and the anode side plate respectively to form sealing ring countersunk holes for placing the sealing rings.

[0015] Furthermore, the inclined side of the countersunk hole of the sealing ring is inclined upward through the anode side plate to form a slope, and the slope is connected to the hydrogen flow channel.

[0016] In this way, the countersunk hole slope design of the sealing ring reduces the wind resistance of air intake and exhaust, promotes air intake and exhaust, and improves reaction efficiency.

[0017] Furthermore, the flow diversion assembly includes a gas transition block covering the countersunk hole of the sealing ring, and gas diversion columns are spaced apart within the gas transition block.

[0018] In this way, the gas transition block is installed at the air hole of the double-sided plate, and the gas is evenly dispersed or concentrated into the air hole through the gas diversion column.

[0019] Furthermore, the sidewall of the plate has a recessed detection hole that penetrates the cathode side plate along the thickness direction, and two detection holes are symmetrically arranged in the width direction of the plate.

[0020] In this way, a temperature sensor can be placed in one detection hole to monitor the temperature in real time, and a voltage detection probe can be placed in another detection hole to monitor the voltage difference between each bipolar plate.

[0021] An air-cooled fuel cell includes a fuel cell bipolar plate as described above.

[0022] In summary, the present invention has the advantages of enhancing mass transfer and controlling pressure and flow rate balance, and improving reaction efficiency. Attached Figure Description

[0023] Figure 1 and Figure 3 These are schematic diagrams of the three-dimensional structure of the cathode and anode sides of the bipolar plate of an air-cooled fuel cell.

[0024] Figure 2 and Figure 4 They are respectively Figure 1 and Figure 3 A partially enlarged structural diagram.

[0025] Figure 5 This is a schematic diagram of an air-cooled fuel cell structure.

[0026] Figure 6 This is a schematic diagram of the three-dimensional structure of the gas transition block.

[0027] Reference numerals: 1. Plate body; 11. Cathode side plate; 111. First oxygen flow channel; 112. Second oxygen flow channel; 113. Open circuit channel; 12. Anode side plate; 121. Hydrogen flow channel; 122. Transverse flow channel; 123. Turbulence channel; 124. Slope; 13. Pore; 131. Sealing ring countersunk hole; 14. Detection hole; 2. Gas transition block; 21. Gas diversion column Detailed Implementation

[0028] The present invention will be further described in detail below with reference to the embodiments.

[0029] An air-cooled fuel cell bipolar plate, such as Figures 1-6 As shown, it includes a rectangular plate 1, with a cathode side plate 11 and an anode side plate 12 on both sides of the thickness direction of the plate 1; the plate 1 is provided with a gas hole 13 for hydrogen to enter or exit, and is symmetrically arranged along its diagonal direction, and the gas hole 13 is provided with a flow diversion component on the anode side plate 12.

[0030] The anode side plate 12 has multiple L-shaped hydrogen flow channels 121, which are symmetrically arranged along the other diagonal direction of the plate body 1. Between the two sets of hydrogen flow channels 121, there are transverse flow channels 122 arranged along the width direction of the plate body 1, and multiple transverse flow channels 122 are arranged along the length direction of the plate body 1. The transverse flow channels 122 are connected to the corresponding hydrogen flow channels 121 in sequence along the length direction of the plate body 1. The sidewall of each transverse flow channel 122 is separated from the sidewall of the corresponding hydrogen flow channel 121, so that a turbulence channel 123 is formed between the multiple hydrogen flow channels 121 and the multiple transverse flow channels 122. The two sets of hydrogen flow channels 121 are respectively connected to the corresponding gas holes 13, so that the gas holes 12, hydrogen flow channels 121 and transverse flow channels 122 form an overall S-shaped anode flow channel for hydrogen to enter and exit.

[0031] The above structure, with its centrally symmetrical hydrogen flow channels and transverse flow channels along the width, ensures that the length of each anode flow channel on the anode side plate remains consistent. This helps stabilize hydrogen pressure and prevents excessive gas pressure loss due to excessively long single flow channels, which could lead to low gas concentration in the latter half of the flow channel, reduced current density, and flooding. Furthermore, the centrally symmetrically arranged vents at both diagonal ends save space and improve the space utilization of the bipolar plate compared to the traditional method of vents occupying the entire width of the bipolar plate at both ends along the length. The overall S-shaped arrangement of the anode flow channels facilitates the formation of negative pressure within the channels, expelling liquid water and gas. Turbulence channels are provided between the hydrogen flow channels, ensuring interconnectivity and reducing localized "starvation" or "enrichment" caused by uneven flow rates. This improves the uniformity of current density distribution, enhances gas diffusion into the GDL, and increases reaction efficiency.

[0032] Among them, such as Figure 1 As shown, the cathode side plate 11 is provided with an oxygen channel for oxygen flow. The oxygen channel includes a first oxygen flow channel 111 and a second oxygen flow channel 112 disposed between the two air holes 13. Multiple first oxygen flow channels 111 and second oxygen flow channels 112 are evenly distributed along the length direction of the plate body 1. Two sets of first oxygen flow channels 111 are disposed along the width direction of the plate body 1 and are centrally symmetrical. The second oxygen flow channels 112 are sequentially connected to the corresponding first oxygen flow channels 111 along the length direction of the plate body 1, so that they form an overall Z-shaped oxygen channel on the cathode side plate 11. A gap is left between the sidewall of the first oxygen flow channel 111 and the sidewall of the second oxygen flow channel 112, so that an open channel 113 is formed between the multiple oxygen channels.

[0033] In this way, the parallel Z-shaped oxygen channel design increases the contact area between air and heat dissipation fins, improving heat dissipation efficiency. At the same time, it increases the contact area between air in each flow channel and the cathode surface of the membrane electrode during use, greatly improving oxygen supply efficiency. The oxygen channel is equipped with an open channel to increase air turbulence, increase the rate at which oxygen passes through the diffusion layer GDL, and draw the liquid water under the ridge into the mainstream to carry it away, meeting the flow channel drainage requirements.

[0034] When implementing, such as Figure 3 As shown, the width of the turbulence channel 123 is less than or equal to the width of the hydrogen flow channel 121, and the width of the turbulence channel 123 is greater than half the width of the hydrogen flow channel 121. In specific implementations, the width of the turbulence channel 123 is 0.75 times the width of the hydrogen flow channel 121, because this increases local turbulence while better addressing the problem of excessive hydrogen enrichment. The width of the open channel 113 is equal to the width of the oxygen channel.

[0035] In specific implementation, such as Figures 3-4 As shown, in order to reduce the air resistance during intake and exhaust, promote intake and exhaust, and improve reaction efficiency, the vents 13 are arranged in an isosceles right-angled triangle, and recesses are formed on the cathode side plate 11 and the anode side plate 12 to form sealing ring countersunk holes 131 for placing sealing rings. The hypotenuse of the sealing ring countersunk hole 131 extends obliquely upward through the anode side plate 12 to form a ramp 124, which is connected to the hydrogen flow channel 121.

[0036] like Figure 6 As shown, in order to uniformly disperse or concentrate the gas into the vent, the flow distribution assembly includes a gas transition block 2 covering the countersunk hole 131 of the sealing ring, and gas flow distribution columns 21 are spaced out in the gas transition block 2.

[0037] In specific implementation, such as Figure 1 , Figure 2 and Figure 5 As shown, in order to better monitor the temperature and the voltage difference between each bipolar plate in real time, the side wall of the plate body 1 has a recessed detection hole 14 that penetrates the cathode side plate 11 along the thickness direction. Two detection holes 14 are symmetrically arranged in the width direction of the plate body 1. In this way, one detection hole can be used to place a temperature sensor, and the other detection hole can be used to place a voltage detection probe.

[0038] An air-cooled fuel cell includes a fuel cell bipolar plate as described above. In a specific implementation, such as... Figure 5 As shown, the two ends of the fuel in the air-cooled fuel cell along its length are fixed by stainless steel pull plates to replace the traditional metal rods. This helps to make full use of the space of the bipolar plates and saves material on the end plates.

[0039] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An air-cooled fuel cell bipolar plate, comprising a rectangular plate (1) with a cathode side plate (11) and an anode side plate (12) on both sides in the thickness direction of the plate (1); characterized in that, The plate (1) is provided with a gas hole (13) for hydrogen to enter or exit, and is symmetrically arranged along its diagonal direction. The gas hole (13) is provided with a flow diversion component on the anode side plate (12). The anode side plate (12) has multiple L-shaped hydrogen flow channels (121) arranged symmetrically along the other diagonal direction of the plate body (1); between the two sets of hydrogen flow channels (121) there is a transverse flow channel (122) arranged along the width direction of the plate body (1), and multiple transverse flow channels (122) are arranged along the length direction of the plate body (1), and the transverse flow channels (122) are sequentially connected to the corresponding hydrogen flow channels (121) along the length direction of the plate body (1); and each of the L-shaped hydrogen flow channels (121) has multiple transverse flow channels (122) arranged along the length direction of the plate body (1). The sidewall of the transverse flow channel (122) and the sidewall of the corresponding hydrogen flow channel (121) are separated, so that a turbulence channel (123) is formed between the multiple hydrogen flow channels (121) and the multiple transverse flow channels (122). The two sets of hydrogen flow channels (121) are respectively connected to the corresponding gas holes (13), so that the gas holes (12), hydrogen flow channels (121) and transverse flow channels (122) form an S-shaped anode flow channel for hydrogen to enter and exit. The cathode side plate (11) is provided with an oxygen channel for oxygen flow. The oxygen channel includes a first oxygen channel (111) and a second oxygen channel (112) disposed between the two air holes (13). The first oxygen channel (111) and the second oxygen channel (112) are evenly distributed along the length direction of the plate (1). The first oxygen channel (111) is arranged in two sets along the width direction of the plate (1) and is centrally symmetrical. The second oxygen channel (112) is connected to the corresponding first oxygen channel (111) in sequence along the length direction of the plate (1) so that it forms an overall Z-shaped oxygen channel on the cathode side plate (11). There is a gap between the side wall of the first oxygen channel (111) and the side wall of the second oxygen channel (112) so that an open channel (113) is formed between the multiple oxygen channels.

2. The air-cooled fuel cell bipolar plate as described in claim 1, characterized in that, The width of the turbulence channel (123) is less than or equal to the width of the hydrogen flow channel (121), and the width of the turbulence channel (123) is greater than half of the hydrogen flow channel (121); the width of the open channel (113) is equal to the width of the oxygen channel.

3. The air-cooled fuel cell bipolar plate as described in claim 1, characterized in that, The vents (13) are arranged in isosceles right triangles, and recesses are formed on the cathode side plate (11) and the anode side plate (12) respectively to form sealing ring countersunk holes (131) for placing sealing rings.

4. The air-cooled fuel cell bipolar plate as described in claim 3, characterized in that, The inclined side of the countersunk hole (131) of the sealing ring is inclined upward through the anode side plate (12) to form a slope (124), and the slope (124) is connected to the hydrogen flow channel (121).

5. The air-cooled fuel cell bipolar plate as described in claim 4, characterized in that, The diversion assembly includes a gas transition block (2) covering the countersunk hole (131) of the sealing ring, and gas diversion columns (21) are spaced apart in the gas transition block (2).

6. The air-cooled fuel cell bipolar plate as described in claim 1, characterized in that, The plate (1) has a recessed detection hole (14) on its side wall, which penetrates the cathode side plate (11) along the thickness direction. There are two detection holes (14) symmetrically arranged in the width direction of the plate (1).

7. An air-cooled fuel cell, characterized in that, This includes using the fuel cell bipolar plate as described in any one of claims 1 to 6.

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