Hydrogen fuel cell cathode gas supply system

Abstract

The invention discloses a hydrogen fuel cell cathode gas supply system which comprises a hydrogen fuel stack, and a gas separator, a gas-liquid separator and a circulating fan are sequentially connected between a cathode inlet of the hydrogen fuel stack and a cathode outlet of the hydrogen fuel stack to form a residual oxygen circulation loop; a layer of oxygen separation membrane is arranged in the gas separator to divide the gas separator into a compressed gas cavity and an oxygen gas cavity; the gas-liquid separator and a cathode inlet of the fuel stack are respectively connected to two sides of the oxygen gas cavity; an exhaust electromagnetic valve is arranged on one side of the compressed gas cavity, and the other side of the compressed gas cavity is sequentially connected with a gas compressor and an air filter to form a fresh air inlet path; the method has the advantages that the membrane electrode can be kept moist, the reaction time can be prolonged, and the oxygen concentration and the utilization rate can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen fuel cells, and in particular to a cathode gas supply system for a hydrogen fuel cell. Background Art

[0002] The bipolar plate, also known as the current collector, is one of the important components of a hydrogen fuel cell. Its main function is to provide a gas flow channel to prevent the hydrogen and oxygen in the hydrogen fuel cell gas chamber from communicating with each other, and to establish a current path between the positive and negative electrodes in series. Under the premise of maintaining a certain mechanical strength and good gas barrier effect, the thickness of the bipolar plate should be as thin as possible to reduce the conduction resistance to current and heat; while the cathode flow channel of the hydrogen fuel cell mainly introduces oxygen, while providing chemical reaction raw materials for the fuel cell, the flowing air can provide heat dissipation for the fuel cell, ensure the normal operating temperature of the hydrogen fuel cell, and maintain the fuel cell at a suitable performance; however, since the existing hydrogen fuel cells generally use a linear cathode flow channel, if the oxygen is introduced due to high heat dissipation intensity, the oxygen contact time will be short, the fuel cell will be limited by the rate of the catalyst and the reaction will not be sufficient, and the oxygen introduction rate will be too fast, which will cause a large amount of water in the fuel cell to be taken away, resulting in cracking of the membrane electrode; it will cause irreversible damage to the stack and reduce the service life; therefore, the present invention provides a hydrogen fuel cell cathode gas supply system that can increase the reaction time of oxygen while ensuring heat dissipation and keep the membrane electrode moist. Summary of the invention

[0003] In view of the above-mentioned deficiencies of the prior art, the technical problem to be solved by the present invention is: how to provide a hydrogen fuel cell supply system that can increase the oxygen reaction time and ensure the wetting of the membrane electrode while ensuring the heat dissipation of the fuel cell.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0005] A cathode gas supply system for a hydrogen fuel cell, comprising a hydrogen fuel cell stack; a gas separator, a gas-liquid separator, and a circulating fan are sequentially connected between the cathode inlet of the hydrogen fuel cell stack and the cathode outlet of the hydrogen fuel cell stack to form a residual oxygen circulation loop; wherein a layer of oxygen separation membrane is arranged inside the gas separator to separate the gas separator into a compressed gas chamber and an oxygen gas chamber, and the gas-liquid separator and the cathode inlet of the fuel cell stack are respectively connected to the two sides of the oxygen gas chamber; an exhaust solenoid valve is provided on one side of the compressed gas chamber; a gas compressor and an air filter are sequentially connected on the other side of the compressed gas chamber to form a fresh air intake path;

[0006] The hydrogen fuel cell stack includes a plurality of bipolar plates stacked on each other, an oxygen flow channel is provided on the cathode side of the bipolar plate along its width direction and penetrates the cathode side along its thickness direction, a plurality of oxygen flow channels are arranged at equal intervals along the length direction of the bipolar plate, the cross-section of the oxygen flow channel is fan-shaped as a whole, and the inner wall of the oxygen flow channel is arranged in an S-shape along its length direction as a whole.

[0007] With the above structure, the gas compressor compresses air from the outside of the air filter into the gas separator to remove impurities in the air, and the oxygen separation membrane separates the oxygen in the gas mixing chamber into the oxygen gas chamber to increase the concentration of oxygen. In this way, the oxygen in the oxygen gas chamber enters from the cathode inlet of the hydrogen fuel cell stack to react with the hydrogen, and then the remaining unreacted oxygen flows out from the anode of the hydrogen fuel cell stack and returns to the oxygen gas chamber through the circulation fan. The gas-liquid separator connected between the oxygen gas chamber and the circulation fan can be used to remove water vapor in the recycled oxygen to prevent excessive condensation of water vapor. In the oxygen gas chamber, the oxygen in the compressed gas chamber is blocked from entering the oxygen gas chamber; the inner wall of the oxygen flow channel is generally S-shaped, which is beneficial to slow down the flow rate of oxygen and increase the reaction time. On the other hand, the inner wall facing the direction of oxygen entry will play a guiding role, so that the incoming oxygen can flow toward the side of the opening and fully contact the membrane electrode, further improving the oxygen utilization rate. In addition, when the water vapor produced by hydrogen and oxygen condenses on the inner wall, it is easy to condense and slide equidistantly along the slope, providing suitable moisture for the membrane electrode, keeping the membrane electrode moist, so as to maintain the performance state of the membrane electrode.

[0008] Furthermore, a pressure sensor is provided between the gas compressor and the compressed gas chamber.

[0009] In this way, the pressure sensor can adjust the working efficiency of the gas compressor according to the pressure in the compressed gas chamber and control the exhaust solenoid valve to discharge the separated residual air in the compressed gas chamber.

[0010] Furthermore, a nitrogen separation membrane is provided on the side of the gas separation chamber facing away from the oxygen gas chamber.

[0011] In this way, the majority of nitrogen in the air can be directly discharged from the compressed gas chamber, which is beneficial for the gas compressor to directly fill the compressed gas chamber with fresh air, saving the exhaust time of the exhaust valve and the time for the gas compressor to refill air, which is beneficial to ensure the stability of the supply.

[0012] Furthermore, a plurality of guide columns are arranged in the vertical direction inside the gas-liquid separator, and the guide columns have spiral blades extending in the radial direction. The bottom of the gas-liquid separator is arranged in a funnel shape and is connected to a drain valve; the circulating fan is connected to the lower side of the gas-liquid separator and is higher than the drain valve, and the oxygen gas chamber is connected to the upper end of the gas-liquid separator.

[0013] In this way, after the circulating oxygen enters the gas-liquid separator, it will climb upward along the spiral blades driven by the pressure of the heated oxygen circulation fan and enter the oxygen gas chamber from the top. The water vapor in the oxygen will condense into small water droplets after encountering the spiral blades, and converge to the drain valve along the spiral blades downward, and be discharged from the gas-liquid separator as the drain valve opens.

[0014] In summary, the present invention has the advantages of ensuring the wetting of the membrane electrode and prolonging the reaction time to increase the oxygen concentration and utilization rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the structure of the present invention.

[0016] Figure 2 It is a schematic diagram of the side view structure of the bipolar plate.

[0017] Figure 3 for Figure 2 Schematic diagram of the enlarged structure.

[0018] Figure 4 Schematic diagram of the three-dimensional structure of the bipolar plate.

[0019] Figure 5 for Figure 4 Schematic diagram of the enlarged structure.

[0020] Reference numerals:

[0021] 1. Hydrogen fuel cell stack, 2. Gas-liquid separator, 3. Gas separator, 31. Compressed gas chamber, 32. Oxygen gas chamber, 33. Oxygen separation membrane, 34. Nitrogen separation membrane, 4. Circulation fan, 6. Gas compressor, 7. Air filter, 8. Bipolar plate, 81 Oxygen flow channel, 9. Pressure sensor DETAILED DESCRIPTION

[0022] The present invention is further described in detail below in conjunction with embodiments.

[0023] A hydrogen fuel cell cathode gas supply system, such as Figure 1 to Figure 5As shown, it includes a hydrogen fuel cell stack 1; between the cathode inlet of the hydrogen fuel cell stack 1 and the cathode outlet of the hydrogen fuel cell stack 1, a gas separator 3, a gas-liquid separator 2, and a circulating fan 4 are sequentially connected to form a residual oxygen circulation loop; wherein, a layer of oxygen separation membrane 33 is arranged inside the gas separator 3 to separate the gas separator 3 into a compressed gas chamber 31 and an oxygen gas chamber 32, and the gas-liquid separator 2 and the cathode inlet of the fuel cell stack 1 are respectively connected to the two sides of the oxygen gas chamber 32; an exhaust solenoid valve on one side of the compressed gas chamber 31; the other side of the compressed gas chamber 31 is sequentially connected to a gas compressor 6 and an air filter 7 to form a fresh air inlet path, and a pressure sensor 9 is also arranged between the gas compressor 6 and the compressed gas chamber 31;

[0024] The hydrogen fuel cell stack 1 includes a plurality of bipolar plates 8 stacked on each other, an oxygen flow channel 81 is provided on the cathode side of the bipolar plate 8 along its width direction and penetrates the cathode side along its thickness direction, a plurality of oxygen flow channels 81 are arranged at equal intervals along the length direction of the bipolar plate 8, the cross-section of the oxygen flow channel is generally fan-shaped or rectangular, and the inner wall of the oxygen flow channel 81 is generally S-shaped along its length direction.

[0025] With the above structure, the gas compressor compresses air from the outside of the air filter into the gas separator to remove impurities in the air, and the oxygen separation membrane separates the oxygen in the gas mixing chamber into the oxygen gas chamber to increase the concentration of oxygen, so that the oxygen in the oxygen gas chamber enters from the cathode inlet of the hydrogen fuel cell stack to react with the hydrogen, and then the remaining unreacted oxygen flows out from the anode of the hydrogen fuel cell stack and returns to the oxygen gas chamber through the circulating fan, and the pressure sensor connected to the compressed air chamber can adjust the working efficiency of the gas compressor according to the pressure in the compressed gas chamber and control the exhaust solenoid valve to discharge the remaining separated air in the compressed gas chamber. The gas-liquid separator connected between the oxygen gas chamber and the circulating fan can be used to remove water vapor in the circulating oxygen to prevent excessive condensation of water vapor in the oxygen gas chamber and hinder the oxygen in the compressed gas chamber from entering the oxygen gas chamber; the inner wall of the oxygen flow channel is generally S-shaped, which is beneficial to slow down the flow rate of oxygen and increase the reaction time. On the other hand, the inner wall facing the direction of oxygen entry will play a guiding role, so that the incoming oxygen can flow toward one side of the opening and fully contact the membrane electrode, further improving the utilization rate of oxygen. In addition, when the water vapor produced by hydrogen and oxygen condenses on the inner wall, it is easy to condense and slide equidistantly along the slope, providing suitable moisture for the membrane electrode, keeping the membrane electrode moist, so as to maintain the performance state of the membrane electrode.

[0026] When implementing it, Figure 1As shown, in order to reduce the exhaust times of the exhaust solenoid valve and realize the rapid filling of the compressed gas chamber with fresh air, a nitrogen separation membrane 34 is provided on the side of the gas separation chamber away from the oxygen gas chamber.

[0027] In order to better separate the water vapor in the oxygen, a plurality of guide columns are arranged in the vertical direction in the gas-liquid separator 2, and the guide columns have spiral blades extending in the radial direction. The bottom of the gas-liquid separator 2 is arranged in a funnel shape and is connected to a drain valve; the circulating fan 4 is connected to the lower side of the gas-liquid separator 2 and is higher than the drain valve, and the oxygen gas chamber 32 is connected to the upper end of the gas-liquid separator 2.

[0028] 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 in the protection scope of the present invention.

Claims

1. A cathode gas supply system for a hydrogen fuel cell, comprising a hydrogen fuel cell stack (1), characterized in that: A gas separator (3), a gas-liquid separator (2), and a circulating fan (4) are sequentially connected between the cathode inlet of the hydrogen fuel cell stack (1) and the cathode outlet of the hydrogen fuel cell stack (1) to form a residual oxygen circulation loop; wherein a layer of oxygen separation membrane (33) is arranged inside the gas separator (3) to separate the gas separator (3) into a compressed gas chamber (31) and an oxygen gas chamber (32); the gas-liquid separator (2) and the cathode inlet of the fuel cell stack (1) are respectively connected to the two sides of the oxygen gas chamber (32); an exhaust solenoid valve is provided on one side of the compressed gas chamber (31), and a gas compressor (6) and an air filter (7) are sequentially connected on the other side of the compressed gas chamber (31) to form a fresh air intake path; The hydrogen fuel cell stack (1) comprises a plurality of bipolar plates (8) stacked on each other, an oxygen flow channel (81) is provided on the cathode side of the bipolar plate (8) along its width direction and penetrates the cathode side along its thickness direction, a plurality of oxygen flow channels (81) are arranged at equal intervals along the length direction of the bipolar plate (8), the cross section of the oxygen flow channel is generally fan-shaped or rectangular, and the inner wall of the oxygen flow channel (81) is generally S-shaped along its length direction.

2. The cathode gas supply system for a hydrogen fuel cell according to claim 1, characterized in that: A pressure sensor (9) is also provided between the gas compressor (6) and the compressed gas chamber (31).

3. The cathode gas supply system for a hydrogen fuel cell according to claim 2, characterized in that: A nitrogen separation membrane (34) is arranged on the side of the gas separation chamber facing away from the oxygen gas chamber.

4. The cathode gas supply system for a hydrogen fuel cell according to claim 1, wherein: A plurality of guide columns are arranged in the vertical direction inside the gas-liquid separator (2), and the guide columns have spiral blades extending in the radial direction. The bottom of the gas-liquid separator (2) is arranged in a funnel shape and is connected to a drain valve. The circulating fan (4) is connected to the lower side of the gas-liquid separator (2) and is higher than the drain valve. The oxygen gas chamber (32) is connected to the upper end of the gas-liquid separator (2).

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