Fuel cell flow channel, bipolar plate, fuel cell and gas flow control method

Abstract

The present invention discloses a fuel cell flow channel, a bipolar plate, a fuel cell, and a gas flow control method. The fuel cell flow channel includes an air inlet section and an air outlet section. The fuel cell flow channel also includes a contraction section and a circulation section. Gas enters the contraction section from the air inlet section and then passes through the circulation section to form a gas circulation within the fuel cell flow channel. The fuel cell flow channel of the present invention provides a contraction section on the fuel cell flow channel and a circulation section after the contraction section to achieve accelerated gas circulation within the fuel cell flow channel. This allows accelerated hydrogen circulation within the fuel cell, improves hydrogen utilization, avoids adding an additional hydrogen circulation system outside the fuel cell, reduces the space occupied by the entire system, and reduces the overall mass. It can also reduce the time that the humidity in the fuel cell flow channel increases, thereby improving the performance of the fuel cell.

Description

Technical Field

[0001] The present invention relates to the field of fuel cells, and in particular to a fuel cell flow channel, a bipolar plate, a fuel cell and a gas flow direction control method. Background Art

[0002] A proton exchange membrane fuel cell (PEMFC) uses hydrogen as fuel and oxygen or air as an oxidant, directly converting the chemical energy stored in the fuel and oxidant into electricity. Bipolar plates in PEMFCs serve to isolate the reaction medium, collect and conduct electricity, support the membrane electrodes, conduct heat, provide channels for the reactant gases, evenly distribute the reactant gases, and drain water. Known as the "skeleton" of the fuel cell stack, a well-designed bipolar plate flow path can effectively improve fuel cell performance.

[0003] Currently, the fuel cell flow channels that contact the effective membrane electrode area are either continuous, uninterrupted, or multiple. In the case of multiple fuel cell flow channels, there is no connectivity between the individual fuel cell flow channels, preventing hydrogen from circulating effectively between them. This results in low hydrogen utilization within each fuel cell flow channel. To improve hydrogen utilization, the entire fuel cell system requires the addition of a hydrogen circulation device outside the fuel cell, which takes up space and increases overall mass. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the defect in the prior art that in order to improve the hydrogen utilization rate of the entire fuel cell system, a hydrogen circulation device needs to be added outside the fuel cell, which occupies the entire system space and increases the overall mass. A fuel cell flow channel, bipolar plate, fuel cell and gas flow control method are provided.

[0005] The present invention solves the above technical problems through the following technical solutions:

[0006] A fuel cell flow channel includes an air inlet section and an air outlet section. Its characteristic is that the fuel cell flow channel also includes a contraction section and a circulation section. Gas enters the contraction section from the air inlet section and then passes through the circulation section to form a gas circulation in the fuel cell flow channel.

[0007] In this solution, a contraction section is provided on the fuel cell flow channel, and a circulation section is provided after the contraction section to achieve accelerated circulation of gas in the fuel cell flow channel, so that the circulation of hydrogen can be accelerated inside the fuel cell, thereby improving the hydrogen utilization rate, thereby avoiding the addition of an additional hydrogen circulation system outside the fuel cell, reducing the space occupied by the entire system, and reducing the overall mass; and can reduce the time for the humidity in the fuel cell flow channel to increase, thereby improving the performance of the fuel cell.

[0008] Preferably, the gas outlet section is connected to the circulation section.

[0009] In this solution, the above-mentioned structural form is adopted to facilitate the discharge of water vapor, impurities, and a small portion of hydrogen that has not yet reacted completely during the gas reaction process while facilitating processing.

[0010] Preferably, the fuel cell flow channel further includes a transition section, and the transition section is connected to the contraction section and the circulation section.

[0011] In this solution, the above-mentioned structural form is adopted, and the gas forms a good circulation between the contraction section and the circulation section, so that the gas density per unit area in the fuel cell flow channel is increased, the hydrogen reaction efficiency is improved, and the reaction is made more sufficient and complete, thereby improving the performance of the fuel cell.

[0012] Preferably, it is characterized in that the transition section is connected to the contraction section through an inclined surface.

[0013] In this solution, the above-mentioned structural form is adopted to quickly achieve acceleration of the gas from the transition section to the contraction section.

[0014] Preferably, the angle formed by the inclined surface and the axis of the contraction section is 110°-130°.

[0015] In this solution, the above-mentioned structural form is adopted to achieve a better gas acceleration effect and improve the gas reaction efficiency.

[0016] Preferably, the contraction section is connected to the air intake section via a second inclined surface.

[0017] In this solution, the above-mentioned structural form is adopted to quickly achieve acceleration of the gas from the transition section to the contraction section.

[0018] Preferably, the included angle 2 formed by the second inclined surface and the axis of the contraction section is 110°-130°.

[0019] In this solution, the above-mentioned structural form is adopted to achieve a better gas acceleration effect and improve the gas reaction efficiency.

[0020] Preferably, the circulation section includes a circulation section and a connecting section, the circulation section is connected to the transition section, and both ends of the connecting section are respectively connected to the circulation section.

[0021] In this solution, through the cooperation of the contraction section and the transition section, most of the gas flowing through the flow section enters the connecting section and is re-absorbed into the flow section, so that the gas flow rate can be accelerated again when the gas flow rate gradually slows down during the flow process in the flow section, thereby improving the gas reaction efficiency in the entire fuel cell flow channel.

[0022] Preferably, the flow section is U-shaped, W-shaped or V-shaped.

[0023] In this solution, the above-mentioned structural form is adopted, so that the fuel cell flow channel occupies less space and improves space utilization.

[0024] Preferably, the air outlet section is located at the bottom of the flow section.

[0025] In this solution, the above-mentioned structural form is adopted to facilitate processing, so that when the flow channel is placed vertically, it is more conducive to the discharge of excess gas from the bottom.

[0026] Preferably, the connecting section has an edge away from the air inlet section, the contraction opening has a port away from the air inlet section, and the horizontal distance between the edge and the port is 3-7 mm.

[0027] In this solution, the above-mentioned structural form is adopted, and the contraction section has a better suction effect on the gas in the connecting section, and the gas circulation effect is better.

[0028] Preferably, the diameter of the contraction section is 0.4-0.6 mm.

[0029] In this solution, by adopting the above-mentioned structural form, the contraction section has a better suction effect on the gas in the connecting section, and the gas circulation effect is better.

[0030] A bipolar plate comprises: a body;

[0031] A plurality of fuel cell flow channels as described above and arranged along the same direction are formed on one surface of the body.

[0032] In this solution, multiple fuel cell flow channels are placed in the same direction to improve the gas reaction efficiency on the effective area of ​​the bipolar plate and enhance the fuel cell performance.

[0033] Preferably, the side portions of adjacent fuel cell flow channels are in contact with each other.

[0034] In this solution, the sides of all adjacent fuel cell flow channels are fitted together so that as many fuel cell flow channels as possible are arranged on the bipolar plate to maximize the effective space of the bipolar plate, improve gas reaction efficiency, and enhance fuel cell performance.

[0035] A fuel cell comprising the bipolar plate as described above, a control unit and an air channel, wherein the control unit comprises control unit 1, control unit 2, control unit 3 and control unit 4, and the air channel comprises air channel 1, air channel 2, air channel 3 and air channel 4;

[0036] The air duct 1 is connected to the air inlet section, and a control unit 1 is provided on the air duct 1;

[0037] The second air channel is connected to the air outlet section, and a second control unit is provided on the second air channel;

[0038] The airway three is connected to the airway one and the airway two, and a control unit three is provided on the airway three;

[0039] The airway four is connected to the airway one, and a control unit four is provided on the airway four;

[0040] The control unit is used to control the opening and closing of the airway.

[0041] In this solution, a control unit controls the opening and closing of the gas channels to adjust the gas flow direction within the bipolar plate channels under different operating conditions. This variable gas flow allows the humidity inside the fuel cell to be controlled within a certain range, thereby improving the stability of the fuel cell's performance and extending its service life.

[0042] Preferably, the air duct has connection point one, connection point two and connection point three, the connection point one is located between the air inlet section and the control unit four, the connection point two is located between the air outlet section and the control unit two, and the connection point three is located between the control unit one and the air inlet.

[0043] In this solution, the gas is alternately flowed in and out between the air inlet section and the air outlet section, so that the humidity caused by the reaction can be controlled within a certain range, and the humidity is kept appropriate and stable, thereby improving the performance of the fuel cell and extending the service life of the fuel cell.

[0044] Preferably, the control unit is a solenoid valve;

[0045] Preferably, the control unit three and the control unit four are pulse solenoid valves;

[0046] In this solution, control unit three and control unit four are pulse solenoid valves to better control the gas flow direction, accurately control the humidity change range inside the fuel cell, maintain the humidity at a suitable and stable level, improve the performance of the fuel cell, and extend the service life of the fuel cell.

[0047] A gas flow control method is provided, wherein the method is used to control the gas flow of the bipolar plate as described above, comprising the following steps:

[0048] S1, allowing the gas to enter the contraction section from the intake section and pass through the circulation section for a period of time;

[0049] S2, allowing the gas to enter the circulation section from the gas outlet section and pass through the contraction section for a period of time;

[0050] S3. Repeat the above steps.

[0051] A gas flow control method is provided, the method being used to control the fuel cell as described above, the method comprising the following steps:

[0052] S1, allowing the gas to enter the contraction section from the intake section and pass through the circulation section for a period of time;

[0053] S2, allowing the gas to enter the circulation section from the gas outlet section and pass through the contraction section for a period of time;

[0054] S3. Repeat the above steps.

[0055] Preferably, the control unit is a solenoid valve, and the solenoid valve includes solenoid valve 1, solenoid valve 2, solenoid valve 3 and solenoid valve 4.

[0056] Said S1, opening solenoid valve 1 and solenoid valve 4, closing solenoid valve 2 and solenoid valve 3, so that the gas enters the contraction section from the intake section and passes through the circulation section for a period of time;

[0057] Said S2, opens the electromagnetic valve 2 and the electromagnetic valve 3, closes the electromagnetic valve 1 and the electromagnetic valve 4, and allows the gas to enter the circulation section from the gas outlet section and pass through the contraction section for a period of time.

[0058] On the basis of conforming to the common sense in this field, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present invention.

[0059] The positive progress effect of the present invention is:

[0060] By providing a contraction section on the fuel cell flow channel and a circulation section after the contraction section, the accelerated circulation of gas in the fuel cell flow channel can be achieved, so that the circulation of hydrogen can be accelerated inside the fuel cell, thereby improving the hydrogen utilization rate, thereby avoiding the addition of an additional hydrogen circulation system outside the fuel cell, reducing the space occupied by the entire system, and reducing the overall mass; and it can also reduce the time when the humidity in the fuel cell flow channel increases, thereby improving the performance of the fuel cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 This is a schematic structural diagram of the fuel cell flow channel of Example 1 of the present invention.

[0062] Figure 2 This is a schematic diagram of the partial structure of the fuel cell flow channel of Example 1 of the present invention.

[0063] Figure 3 This is a schematic structural diagram of the fuel cell flow channel of Example 2 of the present invention.

[0064] Figure 4 This is a schematic structural diagram of the fuel cell flow channel of Example 3 of the present invention.

[0065] Figure 5 This is a structural schematic diagram of a gas flow pattern in a flow channel of a fuel cell according to Example 1 of the present invention.

[0066] Figure 6 This is a structural schematic diagram of another gas flow mode in the flow channel of the fuel cell of Example 1 of the present invention.

[0067] Figure 7 A schematic diagram of a gas flow pattern of the gas flow direction control method according to Example 1 of the present invention.

[0068] Figure 8 Schematic diagram of another gas flow mode of the gas flow direction control method of Example 1 of the present invention.

[0069] Description of reference numerals:

[0070] Intake section 1

[0071] Exhaust section 2

[0072] Contraction segment 3

[0073] Loop 4

[0074] Transition 5

[0075] Incline 16

[0076] Incline Two 7

[0077] Circulation section 41

[0078] Connecting section 42

[0079] Angle a

[0080] Angle b

[0081] Horizontal distance c

[0082] Diameter d

[0083] Control Unit 8

[0084] Control Unit 29

[0085] Control Unit 3 10

[0086] Control Unit 4 11

[0087] Airway 12

[0088] Airway 2 13

[0089] Airway 3 14

[0090] Airway 4 15

[0091] Connection point 16

[0092] Connection Point 2 17

[0093] Connection point three 18 DETAILED DESCRIPTION

[0094] The present invention will be described more clearly and completely below by way of embodiments in conjunction with the accompanying drawings, but the present invention is not limited to the scope of the embodiments.

[0095] like Figures 1 to 4 As shown, the fuel cell flow channel of an embodiment of the present invention includes an air intake section 1 and an air outlet section 2. The fuel cell flow channel also includes a contraction section 3 and a circulation section 4. The gas enters the contraction section 3 from the air intake section 1 and then passes through the circulation section 4 to form a gas circulation in the fuel cell flow channel.

[0096] The fuel cell flow channel is where the fuel gas flows. The gas is primarily hydrogen, but also contains some nitrogen and impurities to ensure a stable reaction process. An intake section 1 is typically located at one end of the fuel cell flow channel. Gas enters through a port on one end of the fuel cell flow channel and passes through a contraction section 3. The gas is squeezed by this contraction section 3, causing its flow rate to accelerate. The accelerated gas then enters a circulation section 4, allowing it to circulate within the fuel cell flow channel. By providing a contraction section 3 on the fuel cell flow channel and a circulation section 4 after it, accelerated gas circulation within the fuel cell flow channel is achieved. This allows accelerated gas circulation within the fuel cell. This improves hydrogen utilization, avoids the need for an additional hydrogen circulation system external to the fuel cell, reduces the space occupied by the entire system, and reduces overall mass. Furthermore, it accelerates the hydrogen reaction rate, reduces the time it takes for humidity in the fuel cell flow channel to increase, and improves fuel cell performance.

[0097] For a single fuel cell flow channel, the outlet section 2 can be connected to any location on the fuel cell flow channel except the inlet section 1 and the contraction section 3 to discharge water vapor, impurities, and a small amount of unreacted hydrogen produced during the gas reaction. In this embodiment, the outlet section 2 is connected to the circulation section 4; as a preferred embodiment, the outlet section 2 is located on the circulation section 4 away from the inlet section 1 to facilitate the discharge of water vapor, impurities, and a small amount of unreacted hydrogen produced during the gas reaction while facilitating processing.

[0098] When the contraction section 3 and the circulation section 4 are directly connected, the gas passing through the contraction section 3 exerts little or no attraction on the gas in the circulation section 4, making it difficult for the gas to circulate smoothly. In this embodiment, the transition section 5 is connected to the contraction section 3 and the circulation section 4. That is, the transition section 5 is provided between the contraction section 3 and the circulation section 4. After the gas is accelerated by the contraction section 3, it flows to the circulation section 4. The contraction section 3 in turn exerts an attraction on the gas flowing through the circulation section 4, forming a good circulation between the contraction section 3 and the circulation section 4. This increases the gas density per unit area in the fuel cell flow channel, improves the hydrogen reaction efficiency, and makes the reaction more complete, thereby improving the performance of the fuel cell.

[0099] The transition section 5 and the contraction section 3 can be connected by an arcuate surface or a vertical surface. In this embodiment, the transition section 5 and the contraction section 3 are connected by an inclined surface 6. As a preferred embodiment, the angle α formed by the inclined surface 6 and the axis of the contraction section 3 is 110°-130°.

[0100] The transition section 5 is connected to the contraction section 3 through the inclined surface 16, which can quickly accelerate the gas from the transition section 5 to the contraction section 3. Moreover, under the same working conditions, when the angle 1a formed by the inclined surface 16 and the axis of the contraction section 3 is 110°-130°, a better gas acceleration effect can be achieved, thereby improving the gas reaction efficiency.

[0101] Similarly, the constriction section 3 and the air inlet section 1 can be connected via an arcuate surface or a vertical surface. In this embodiment, the constriction section 3 and the air inlet section 1 are connected via a second inclined surface 7. As a preferred embodiment, the angle b formed between the second inclined surface 7 and the axis of the constriction section 3 is 110°-130°.

[0102] The contraction section 3 and the air intake section 1 are connected through the inclined plane 2 7, which can quickly accelerate the gas between the contraction section 3 and the air intake section 1. Moreover, under the same working conditions, when the angle 2b formed by the inclined plane 2 7 and the axis of the contraction section 3 is 110°-130°, a better gas acceleration effect can be achieved, thereby improving the gas reaction efficiency.

[0103] While ensuring that the angle a formed by the inclined plane 1 6 and the axis of the contraction section 3 is 110°-130°, and the angle b formed by the inclined plane 2 7 and the axis of the contraction section 3 is 110°-130°, the gas acceleration process can be made smoother, the gas reaction process can be ensured to be more stable, and the performance of the fuel cell can be improved.

[0104] To form a gas circulation in the fuel cell flow channel, the gas enters the circulation section 4 from the transition section 5. The circulation section 4 includes a flow section 41 and a connecting section 42. The flow section 41 is connected to the transition section 5, and both ends of the connecting section 42 are respectively connected to the flow section 41.

[0105] With the cooperation of the contraction section 3 and the transition section 5, most of the gas flowing through the flow section 41 enters the connecting section 42 and is re-absorbed into the flow section 41, so that the gas flow rate can be accelerated again when the flow rate of the gas gradually slows down during the flow of the flow section 41, thereby improving the gas reaction efficiency in the entire fuel cell flow channel.

[0106] The shape of the flow section 41 has a bend to form a connection with the connection portion, so the shape of the flow section 41 can be W-shaped or V-shaped. In this embodiment, the shape of the flow section 41 is U-shaped to make the fuel cell flow channel occupy less space and improve space utilization.

[0107] Furthermore, the gas outlet section 2 is located at the bottom of the flow section 41. In this embodiment, the gas outlet section 2 is located at the bottom of the U-shaped flow section 41, away from the ends of the U-shaped flow section 41, to facilitate processing. This allows the flow channel to be placed vertically, which facilitates the discharge of excess gas from the bottom. In other embodiments, the gas outlet section 2 can also be located at any position in the flow section 41.

[0108] The U-shaped flow section 41 has two ports, one of which is connected to the transition section 5, and the other can be directly connected to the port of the connecting section 42. The port of the U-shaped flow section 41 can also be extended to any position between the relative position near the intake section 1 and the port of the connecting section 42. As a preferred embodiment, the other port of the U-shaped flow section 41 extends to be flush with the port of the intake section 1 to fully utilize the effective space of the fuel cell flow channel, increase the sufficient distribution of gas within a certain space, improve the gas reaction efficiency within a certain space, and make the reaction more uniform.

[0109] The connecting section 42 has an edge away from the air inlet section 1, and the contraction port has a port away from the air inlet section 1. When the horizontal distance c between the edge and the port is 3-7 mm, the contraction section 3 has a better suction effect on the gas in the connecting section 42, and the gas circulation effect is better.

[0110] Furthermore, under the working condition that the diameter d of the contraction section 3 is 0.4-0.6 mm, the contraction section 3 has a better suction effect on the gas in the connecting section 42 and a better gas circulation effect.

[0111] This embodiment also discloses a bipolar plate, on one surface of which multiple fuel cell flow channels as described above are formed and placed in the same direction. By placing multiple fuel cell flow channels in the same direction, the gas reaction efficiency on the effective area of ​​the bipolar plate is improved, thereby improving the performance of the fuel cell.

[0112] There are various ways to arrange multiple fuel cell flow channels running in the same direction. All fuel cell flow channels can have gaps between their sides. Alternatively, some adjacent fuel cell flow channels can have their sides aligned, while others can have gaps between their sides. As a preferred approach, all adjacent fuel cell flow channels are aligned, allowing as many fuel cell flow channels as possible to be arranged on the bipolar plate. This maximizes the effective space on the bipolar plate, improves gas reaction efficiency, and enhances fuel cell performance.

[0113] like Figures 5 to 8 As shown, this embodiment also discloses a fuel cell, which includes the bipolar plate, control unit and air channel as above, the control unit includes control unit one 8, control unit two 9, control unit three 10, control unit four 11, and the air channel includes air channel one 12, air channel two 13, air channel three 14 and air channel four 15; air channel one 12 is connected to the air inlet section 1, and control unit one 8 is provided on air channel one 12; air channel two 13 is connected to the air outlet section 2, and control unit two 9 is provided on air channel two 13; air channel three 14 is connected to air channel one 12 and air channel two 13, and control unit three 10 is provided on air channel three 14; air channel four 15 is connected to air channel one 12, and control unit four 11 is provided on air channel four 15; the control unit is used to control the opening and closing of the air channel.

[0114] When control unit one 8 and control unit two 9 are turned on, control unit three 10 and control unit four 11 are turned off, and gas enters from gas channel one 12 and exits from gas channel two 13; when control unit three 10 and control unit four 11 are turned on, control unit one 8 and control unit two 9 are turned off, and gas enters from gas channel three 14 and exits from gas channel four 15. The opening and closing of the gas channel is controlled by the control unit to achieve the flow direction of gas in the flow channel of the bipolar plate under different working conditions. When gas enters from gas channel one 12 and exits from gas channel two 13, the gas flow rate is accelerated, the reaction is accelerated, and the humidity increases; when gas enters from gas channel three 14 and exits from gas channel four 15, the gas flow rate is relatively slow, the reaction is relatively slow, and the humidity is relatively reduced. The different gas flow directions can make the humidity inside the fuel cell controllable to a certain extent, thereby improving the stability of fuel cell performance and extending the service life of the fuel cell.

[0115] The air duct has connection point one 16, connection point two 17 and connection point three 18. Connection point one 16 is located between the air inlet section 1 and control unit four 11, connection point two 17 is located between the air outlet section 2 and control unit two 9, and connection point three 18 is located between control unit one 8 and the air inlet.

[0116] Specifically, gas enters from the air inlet, passes through connection point three 18, connection point one 16, enters air inlet section 1, exits air outlet section 2, and is discharged through connection point two 17. Gas also enters from the air inlet, passes through connection point three 18, connection point two 17, enters air outlet section 2, exits air inlet section 1, and is discharged through connection point one 16. By alternating the flow of gas between air inlet section 1 and air outlet section 2, the humidity generated by the reaction can be controlled within a certain range, maintaining an appropriate and stable humidity, thereby improving fuel cell performance and extending the service life of the fuel cell.

[0117] There can be many types of control units. In this embodiment, the control unit is a solenoid valve.

[0118] As a preferred solution, control unit 2 9 and control unit 4 11 are pulse solenoid valves to better control the gas flow direction, accurately control the humidity change range inside the fuel cell, maintain the humidity at a suitable and stable level, improve the performance of the fuel cell, and extend the service life of the fuel cell.

[0119] This embodiment further discloses a gas flow direction control method, which is used to control the gas flow direction of the bipolar plate as described above, comprising the following steps:

[0120] S1, allowing the gas to enter the contraction section 3 from the intake section 1 and pass through the circulation section 4 for a period of time;

[0121] S2, allowing the gas to enter the circulation section 4 from the outlet section 2 and pass through the contraction section 3 for a period of time;

[0122] S3. Repeat the above steps.

[0123] By controlling the gas flow direction, the gas is alternately flowed in and out between the air inlet section 1 and the air outlet section 2, so that the humidity caused by the reaction can be controlled within a certain range, keeping the humidity appropriate and stable, thereby improving the stability of the fuel cell performance and extending the service life of the fuel cell.

[0124] This embodiment also discloses a gas flow control method, which is used to control the above fuel cell, and includes the following steps:

[0125] S1, allowing the gas to enter the contraction section 3 from the intake section 1 and pass through the circulation section 4 for a period of time;

[0126] S2, allowing the gas to enter the circulation section 4 from the outlet section 2 and pass through the contraction section 3 for a period of time;

[0127] S3. Repeat the above steps.

[0128] By controlling the gas flow direction, the gas is alternately flowed in and out between the air inlet section 1 and the air outlet section 2, so that the humidity caused by the reaction can be controlled within a certain range, keeping the humidity appropriate and stable, thereby improving the stability of the fuel cell performance and extending the service life of the fuel cell.

[0129] Specifically, the control unit in the above steps is a solenoid valve, which includes solenoid valve 1, solenoid valve 2, solenoid valve 3 and solenoid valve 4.

[0130] S1, open solenoid valve 1 and solenoid valve 2, close solenoid valve 3 and solenoid valve 4, so that the gas enters the contraction section 3 from the intake section 1 and passes through the circulation section 4 for a period of time;

[0131] S2. Open solenoid valve 3 and solenoid valve 4, and close solenoid valve 1 and solenoid valve 2, so that the gas enters the circulation section 4 from the outlet section 2 and passes through the contraction section 3 for a period of time.

[0132] Although specific embodiments of the present invention have been described above, those skilled in the art will appreciate that these are merely illustrative and that the scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, and such changes and modifications are intended to fall within the scope of the present invention.

Claims

1. A fuel cell flow channel, comprising an air inlet section and an air outlet section, characterized in that: The fuel cell flow channel further includes a contraction section and a circulation section, wherein the gas enters the contraction section from the air inlet section and then passes through the circulation section to form a gas circulation in the fuel cell flow channel; The fuel cell flow channel further includes a transition section, wherein the transition section is connected to the contraction section and the circulation section; The circulation section includes a circulation section and a connecting section, the circulation section is connected to the transition section, and both ends of the connecting section are respectively connected to the circulation section; The transition section is connected to the contraction section via an inclined plane. The angle formed by the inclined surface 1 and the axis of the contraction section is 110°-130°; The contraction section is connected to the air intake section via a second inclined surface; An included angle 2 formed between the second inclined surface and the axis of the contraction section is 110°-130°.

2. The fuel cell flow channel according to claim 1, wherein: The gas outlet section is communicated with the circulation section.

3. The fuel cell flow channel according to claim 1, wherein: The flow section is U-shaped, W-shaped or V-shaped.

4. The fuel cell flow channel according to claim 3, wherein: The air outlet section is located at the bottom of the flow section.

5. The fuel cell flow channel according to claim 1, wherein: The connecting section has an edge away from the air inlet section, the contraction section has a port away from the air inlet section, and a horizontal distance between the edge and the port is 3-7 mm.

6. The fuel cell flow channel according to claim 1, wherein: The diameter of the contraction section is 0.4-0.6 mm.

7. A bipolar plate, characterized in that: It includes: ontology; A plurality of fuel cell flow channels according to any one of claims 1 to 6 are formed on one surface of the body and are arranged in the same direction.

8. The bipolar plate according to claim 7, wherein: The side portions of adjacent fuel cell flow channels are in contact with each other.

9. A fuel cell, characterized in that: It comprises the bipolar plate according to claim 7 or 8, a control unit and an airway, wherein the control unit comprises control unit 1, control unit 2, control unit 3 and control unit 4, and the airway comprises airway 1, airway 2, airway 3 and airway 4; The air duct 1 is connected to the air inlet section, and a control unit 1 is provided on the air duct 1; The second air channel is connected to the air outlet section, and a second control unit is provided on the second air channel; The airway three is connected to the airway one and the airway two, and a control unit three is provided on the airway three; The airway four is connected to the airway one, and a control unit four is provided on the airway four; The control unit is used to control the opening and closing of the airway.

10. The fuel cell according to claim 9, wherein The air duct has connection point one, connection point two and connection point three, connection point one is located between the air inlet section and the control unit four, connection point two is located between the air outlet section and the control unit two, and connection point three is located between the control unit one and the air inlet.

11. The fuel cell according to claim 9, wherein The control unit is a solenoid valve.

12. The fuel cell according to claim 9, wherein The control unit three and the control unit four are pulse solenoid valves.

13. A gas flow control method, characterized in that: The method for controlling the gas flow direction of the bipolar plate according to claim 7 or 8 comprises the following steps: S1, allowing the gas to enter the contraction section from the intake section and pass through the circulation section for a period of time; S2, allowing the gas to enter the circulation section from the gas outlet section and pass through the contraction section for a period of time; S3. Repeat the above steps.

14. A gas flow control method, characterized in that: The method is used to control the fuel cell according to claim 9, and the method comprises the following steps: S1, allowing the gas to enter the contraction section from the intake section and pass through the circulation section for a period of time; S2, allowing the gas to enter the circulation section from the gas outlet section and pass through the contraction section for a period of time; S3. Repeat the above steps.

15. The gas flow control method according to claim 14, wherein: The control unit is a solenoid valve, which includes solenoid valve 1, solenoid valve 2, solenoid valve 3 and solenoid valve 4. Said S1, opening solenoid valve 1 and solenoid valve 4, closing solenoid valve 2 and solenoid valve 3, so that the gas enters the contraction section from the intake section and passes through the circulation section for a period of time; Said S2, opens the electromagnetic valve 2 and the electromagnetic valve 3, closes the electromagnetic valve 1 and the electromagnetic valve 4, and allows the gas to enter the circulation section from the gas outlet section and pass through the contraction section for a period of time.

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