A fuel cell system based on atomization humidification mode and humidity regulation method thereof

Abstract

The present invention relates to a fuel cell system based on an atomization humidification method and a humidity regulation method thereof. The fuel cell system includes a fuel cell stack, a hydrogen supply subsystem, and an oxygen supply subsystem; the hydrogen source of the hydrogen supply subsystem is sequentially connected to a proportional valve, an ejector, and an anode inlet of the fuel cell stack, the anode outlet of the fuel cell stack is connected to a water distributor, and the gas outlet of the water distributor is connected to the ejector; the first outlet of the air compressor of the oxygen supply subsystem is sequentially connected to a mixing chamber and a cathode inlet of the fuel cell stack, the second outlet of the air compressor is connected to the gas inlet of the atomizer; the cathode outlet of the fuel cell stack is connected to a tail pipe; the liquid inlet of the water collecting tank is connected to the liquid outlet of the water distributor, and the liquid outlet of the water collecting tank is sequentially connected to a spray water pump, an atomizer, and a mixing chamber. By means of atomization humidification, the intake flow rate and intake pressure are controlled to achieve active humidity regulation under variable working conditions. On the one hand, this is beneficial to prolonging the life of the fuel cell stack and achieving better fuel cell stack water management; on the other hand, it provides a solution for precise humidity control.

Description

Technical Field

[0001] The present invention relates to the field of fuel cells, and in particular to a fuel cell system based on an atomization humidification mode and a humidity regulation method thereof. Background Art

[0002] In fuel cell systems, air inlet humidification is an important way to solve the hydrothermal management of the fuel cell stack. Existing technologies mainly include bubbling humidification, membrane humidification and other methods. However, in vehicle-mounted application scenarios, membrane humidification is still the main method, and bubbling humidification is mostly suitable for laboratories.

[0003] The principle of the membrane humidification method is that the humidified gas at the air outlet enters the air inlet through the membrane reverse osmosis, humidifying the air at the air inlet. The membrane humidification method is passive control, and the adjustment of humidity depends on the number of membrane tubes. For vehicle-mounted variable load conditions, the humidity required for different conditions is different, so the membrane humidification method cannot adapt to vehicle-mounted variable load conditions in a friendly manner. Therefore, it is necessary to provide a humidification device with actively adjustable humidity based on the vehicle-mounted scenario, specifically, to provide a fuel cell system based on atomization humidification and its humidity adjustment method to solve the problems existing in the above-mentioned existing technologies. Summary of the Invention

[0004] In view of this, the present invention provides a fuel cell system based on atomization humidification and a humidity control method thereof, with the aim of providing a humidifying device with actively adjustable humidity to achieve active humidity adjustment under variable working conditions, thereby increasing the life of the fuel cell stack and achieving better fuel cell stack water management.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A fuel cell system based on an atomization humidification method, the fuel cell system comprising a fuel cell stack, a hydrogen supply subsystem, and an oxygen supply subsystem;

[0007] The hydrogen supply subsystem includes a hydrogen source, a proportional valve, an ejector, and a water separator. The hydrogen source is sequentially connected to the proportional valve, the ejector, and the anode inlet of the fuel cell stack. The anode outlet of the fuel cell stack is connected to the water separator, and the gas outlet of the water separator is connected to the ejector.

[0008] The oxygen supply subsystem includes an air compressor, a mixing chamber, an atomizer, a spray water pump, and a water collecting tank. The first outlet of the air compressor is connected to the mixing chamber and the cathode inlet of the fuel cell stack in sequence, and the second outlet of the air compressor is connected to the gas inlet of the atomizer; the cathode outlet of the fuel cell stack is connected to the tail exhaust pipe; the liquid inlet of the water collecting tank is connected to the liquid outlet of the water distributor, and the liquid outlet of the water collecting tank is connected to the spray water pump, the atomizer, and the mixing chamber in sequence.

[0009] Furthermore, the mixing chamber is used to humidify the gas entering the stack. In the mixing chamber, the high-temperature air flowing out of the first outlet of the air compressor is used to vaporize the droplets sprayed by the atomizer and then uniformly mix them with the air.

[0010] Furthermore, a back pressure valve is provided on the tail exhaust pipe connected to the cathode outlet of the fuel cell stack.

[0011] Furthermore, an air flow meter is provided at the inlet of the air compressor; a first pressure sensor is provided at the cathode inlet of the fuel cell stack; a second pressure sensor is provided on the pipeline between the spray water pump and the atomizer; a temperature and humidity sensor is provided at the outlet of the mixing chamber; a first temperature sensor is provided at the outlet of the cooling path of the fuel cell stack; and a second temperature sensor is provided at the inlet of the cooling path of the fuel cell stack.

[0012] The present invention also provides a humidity control method based on the above fuel cell system, and the humidity control method is specifically as follows:

[0013] When the fuel cell system is running, the liquid water separated by the water separator in the hydrogen supply subsystem enters the water collecting tank, and the liquid water in the water collecting tank enters the atomizer under the action of the spray water pump;

[0014] The air is compressed by the air compressor to produce high-temperature air. A small portion of the high-temperature air flows out through the second outlet of the air compressor and enters the atomizer, which is used to atomize the liquid water in the atomizer into smaller droplets. The majority of the high-temperature air flows out through the first outlet of the air compressor and enters the mixing chamber. In the mixing chamber, the high-temperature air flowing out of the first outlet of the air compressor vaporizes the droplets sprayed by the atomizer and then mixes evenly with the air to humidify the air entering the pile.

[0015] Control the speed of the spray pump to maintain P 雾化 -P 进 =20kPa, to ensure that the atomizer can continuously atomize, P 雾化 is the gas pressure in the pipeline between the spray water pump and the atomizer, which is measured by the second pressure sensor installed in the pipeline between the spray water pump and the atomizer. 进 is the gas pressure at the stack air inlet, measured by a first pressure sensor disposed at the cathode inlet of the stack;

[0016] When the air stoichiometric ratio λ remains unchanged, the stack air inlet gas pressure P is calculated. 进 The value range of

[0017] Adjust the air inlet humidity RH. For a fixed system, each operating point has an optimal humidity value. Set the target RH according to the operating conditions. 目标 , get the humidity value RH fed back from the temperature and humidity sensor 实际 , compared with RH 实际 and RH 目标, and adjust the humidity based on the comparison results.

[0018] Furthermore, when the air stoichiometric ratio λ remains unchanged, the stack air inlet gas pressure P is calculated. 进 The value range of is as follows:

[0019] Calculate the maximum value of the stack air inlet gas pressure To maintain P 雾化 -P 进 =20kPa, P 雾化 Increase, P 进 Also increases, when the atomizing water pump reaches the highest speed, P 雾化 Reaching the maximum value, corresponding to P 进 It also reaches the maximum value, that is, when the atomizing water pump reaches the highest speed, the maximum value of the stack air inlet gas pressure is calculated

[0020] Furthermore, when the air stoichiometric ratio λ remains unchanged, the stack air inlet gas pressure P is calculated. 进 The value range of , the specific method is as follows:

[0021] Calculate the minimum value of the stack air inlet gas pressure The calculation formula is as follows:

[0022]

[0023] Where λ is the air stoichiometric ratio; k is the stack flow resistance coefficient; I is the stack operating current; N is the number of cells in the stack; F is the Faraday constant; M 空气 is the molar mass of air; T 出 is the coolant temperature at the outlet of the cooling path of the fuel cell stack;

[0024] P 进 As the air stoichiometric ratio λ increases, for a fixed λ, the minimum value of the stack inlet gas pressure is calculated by formula (1):

[0025] Stack air inlet gas pressure P 进 The value range is

[0026] Furthermore, the comparison RH 实际 and RH 目标 , adjust the humidity according to the comparison results, as follows:

[0027] When RH 实际 =RH 目标 When the current operating conditions are maintained;

[0028] When RH实际 <RH 目标 When the air metering ratio λ remains unchanged, the back pressure valve opening is increased, the air compressor speed is reduced, and thus P 进 , until the target humidity is met; if P is reduced 进 to If the intake air humidity requirement is still not met, the cathode intake air flow rate is reduced, that is, the air stoichiometric ratio λ is reduced, thereby further reducing Until the target humidity is met;

[0029] When RH 实际 >RH 目标 When the air metering ratio λ remains unchanged, the back pressure valve opening is reduced, the air compressor speed is increased, and P is gradually increased. 进 , until the target humidity is met; if P is increased 进 to If the intake humidity requirement is still not met, set At this time, the highest humidity that can be controlled is reached.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] (1) By setting a mixing chamber at the rear end of the air compressor and using an atomizer to humidify the air entering the stack in the mixing chamber, the traditional membrane humidifier is replaced to reduce the cost of the fuel cell; by setting an air compressor with two outlets, a small part of the high-temperature air compressed by the air compressor is used to flow out through the second outlet of the air compressor into the atomizer, and the liquid water in the atomizer is atomized into smaller droplets; while most of the high-temperature air flows out through the first outlet of the air compressor into the mixing chamber. In the mixing chamber, the high-temperature air flowing out of the first outlet of the air compressor is used to vaporize the droplets sprayed by the atomizer, and then evenly mix with the air to humidify the air entering the stack.

[0032] (2) By setting up a water collecting tank to collect the liquid water separated by the water separator in the hydrogen supply subsystem, liquid water is provided to the atomizer, and the water produced by the fuel cell stack is fully utilized to achieve self-humidification of the fuel cell; at the same time, the gas pressure P at the inlet of the fuel cell stack is determined by accurate formula calculation. 进 The value range of RH is set according to the working conditions. 目标 , get the humidity value RH fed back from the temperature and humidity sensor 实际 , compared with RH 实际 and RH 目标 , and humidity is adjusted based on the comparison results. By controlling the intake air flow and pressure through atomization humidification, active humidity adjustment is achieved under varying operating conditions. This not only helps to extend the life of the fuel cell stack and achieve better fuel cell stack water management, but also provides a solution for precise humidity control.

[0033] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0035] Figure 1 A schematic structural diagram of a fuel cell system based on an atomization humidification method according to an embodiment of the present invention is shown.

[0036] In the figure: 1. Hydrogen source; 2. Proportional valve; 3. Ejector; 4. Fuel cell; 5. Water distributor; 6. Water collecting tank; 7. Spray water pump; 8. Atomizer; 9. Air compressor; 10. Mixing chamber; 11. Back pressure valve; 12. Second temperature sensor; 13. First temperature sensor; 14. Temperature and humidity sensor; 15. First pressure sensor; 16. Second pressure sensor; 17. Air flow meter. DETAILED DESCRIPTION

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0038] The embodiment of the present invention proposes a fuel cell system based on atomization humidification mode, as shown in the attached Figure 1 As shown, the fuel cell system includes a fuel cell stack 4, a hydrogen supply subsystem, and an oxygen supply subsystem;

[0039] The hydrogen supply subsystem includes a hydrogen source 1, a proportional valve 2, an ejector 3, and a water separator 5. The hydrogen source 1 is sequentially connected to the proportional valve 2, the ejector 3, and the anode inlet of the fuel cell stack 4. The anode outlet of the fuel cell stack 4 is connected to the water separator 5. The gas outlet of the water separator 5 is connected to the ejector 3.

[0040] The oxygen supply subsystem includes an air compressor 9, a mixing chamber 10, an atomizer 8, a spray water pump 7, and a water collecting tank 6. The first outlet of the air compressor 9 is connected to the mixing chamber 10 and the cathode inlet of the fuel cell stack 4 in sequence, and the second outlet of the air compressor 9 is connected to the gas inlet of the atomizer 8; the cathode outlet of the fuel cell stack 4 is connected to the tail exhaust pipe; the liquid inlet of the water collecting tank 6 is connected to the liquid outlet of the water separator 5, and the liquid outlet of the water collecting tank 6 is connected to the spray water pump 7, the atomizer 8 and the mixing chamber 10 in sequence.

[0041] The mixing chamber 10 is used to humidify the gas entering the stack. In the mixing chamber 10, the high-temperature air flowing out of the first outlet of the air compressor 9 is used to vaporize the droplets sprayed by the atomizer 8 and then evenly mix with the air to meet the humidification requirements of the air entering the stack.

[0042] A back pressure valve 11 is provided on the tail pipe connected to the cathode outlet of the fuel cell stack 4. By adjusting the speed of the air compressor 9 and the opening of the back pressure valve 11, the air flow rate and the intake pressure entering the stack can be controlled simultaneously.

[0043] An air flow meter 17 is provided at the inlet of the air compressor 9 for detecting the air flow entering the stack; a first pressure sensor 15 is provided at the cathode inlet of the fuel cell stack 4; a second pressure sensor 16 is provided on the pipeline between the spray water pump 7 and the atomizer 8; a temperature and humidity sensor 14 is provided at the outlet of the mixing chamber 10 for detecting the humidity of the air entering the stack; a first temperature sensor 13 is provided at the outlet of the cooling path of the fuel cell stack 4; and a second temperature sensor 12 is provided at the inlet of the cooling path of the fuel cell stack 4.

[0044] An embodiment of the present invention further provides a humidity control method for a fuel cell system based on an atomization humidification method. The humidity control method is specifically as follows:

[0045] When the fuel cell system is running, the liquid water separated by the water separator 5 in the hydrogen supply subsystem enters the water collecting tank 6, and the liquid water in the water collecting tank 6 enters the atomizer 8 under the action of the spray water pump 7;

[0046] The air is compressed by the air compressor 9 to produce high-temperature air. A small portion of the high-temperature air flows out through the second outlet of the air compressor 9 and enters the atomizer 8, which is used to atomize the liquid water in the atomizer 8 into smaller droplets. The majority of the high-temperature air flows out through the first outlet of the air compressor 9 and enters the mixing chamber 10. In the mixing chamber 10, the high-temperature air flowing out of the first outlet of the air compressor 9 vaporizes the droplets sprayed by the atomizer 8 and then mixes evenly with the air to humidify the air entering the pile.

[0047] Control the speed of the spray pump 7 and maintain P 雾化 -P 进 =20kPa, to ensure that the atomizer can continuously atomize without interruption, P 雾化is the gas pressure in the pipeline between the spray water pump 7 and the atomizer 8, which is measured by the second pressure sensor 16 arranged on the pipeline between the spray water pump 7 and the atomizer 8, P 进 is the gas pressure at the stack air inlet, measured by the first pressure sensor 15 provided at the cathode inlet of the stack 4;

[0048] When the air stoichiometric ratio λ remains unchanged, the stack air inlet gas pressure P is calculated. 进 The value range of

[0049] Adjust the air inlet humidity RH. For a fixed system, each operating point has an optimal humidity value. Set the target RH according to the operating conditions. 目标 , obtain the humidity value RH fed back from the temperature and humidity sensor 14 实际 , compared with RH 实际 and RH 目标 , and adjust the humidity based on the comparison results.

[0050] When the air stoichiometric ratio λ remains unchanged, calculate the stack air inlet gas pressure P 进 The value range of is as follows:

[0051] Calculate the maximum value of the stack air inlet gas pressure To maintain P 雾化 -P 进 =20kPa, P 雾化 Increase, P 进 As the speed increases, when the atomizing water pump 7 reaches the maximum speed, P 雾化 Reaching the maximum value, corresponding to P 进 It also reaches the maximum value, that is, when the atomizing water pump 7 reaches the highest speed, the maximum value of the stack air inlet gas pressure is calculated.

[0052] Calculate the minimum value of the stack air inlet gas pressure The calculation formula is as follows:

[0053]

[0054] Where λ is the air stoichiometric ratio; k is the stack flow resistance coefficient; i is the stack operating current; N is the number of cells in the stack; F is the Faraday constant; M 空气 is the molar mass of air; T 出 is the coolant temperature at the outlet of the cooling path of the fuel cell stack;

[0055] From formula (1), we can see that for a fixed fuel cell system, the number of cells N in the stack is fixed; the stack flow resistance coefficient k depends on the size of the stack flow field and is a fixed value; under a certain fixed working condition, the stack operating current I is fixed; generally speaking, the coolant temperature T at the outlet of the stack cooling path is 出 is fixed and depends on the heat dissipation requirements of the cooling system. 进 As the air stoichiometric ratio λ increases, for a fixed λ, the minimum value of the stack inlet gas pressure is calculated by formula (1): To ensure that the collected liquid water meets the requirements of humidification;

[0056] Stack air inlet gas pressure P 进 The value range is

[0057] The derivation process of formula (1) is as follows:

[0058] In a fuel cell system, the hydrogen circuit is circulated and the air circuit is exhausted to the outside. From the perspective of satisfying water balance, the following expression exists:

[0059] Q 空进 +Q 生成 =Q 空出 +Q 氢出 (2);

[0060] Where Q 空进 is the water mass flow rate at the air inlet; Q 空出 is the water mass flow rate at the air outlet; Q 生成 The mass flow rate of water generated by the stack reaction; Q 氢出 is the water mass flow rate at the hydrogen outlet.

[0061] In order to meet the normal requirements of system operation, that is, the liquid water collected by the hydrogen water separator is greater than the water required for air humidification, the following expression exists:

[0062] Q 氢出 ≥Q 空进 (3);

[0063] Substituting formula (2) into formula (3), we can obtain:

[0064] Q 生成 ≥Q 空出 (4);

[0065] For the air outlet, there is an expression for the ratio of the mass of water to the mass of air as follows:

[0066]

[0067] Where m 空出is the air mass flow rate at the air outlet; P 水出 is the partial pressure of water at the air outlet; P 空出 M is the pressure of the air at the air outlet; 水 is the molar mass of water; M 空气 is the molar mass of air.

[0068] For the air tail exhaust, the mass flow rate of the air outlet is the mass flow rate of the air inlet minus the mass flow rate of oxygen consumed by the reaction, that is:

[0069]

[0070] Where λ is the air stoichiometric ratio; I is the operating current of the stack; N is the number of cells in the stack; F is the Faraday constant; M 空气 is the molar mass of air.

[0071] The mass flow rate Q of water generated by the stack reaction 生成 , which is related to the current working current, has the following expression:

[0072]

[0073] And there is the following relationship, the air outlet gas pressure P 出 is the partial pressure of water at the air outlet P 水出 The pressure of the air at the air outlet P 空出 sum:

[0074] P 出 =P 空出 +P 水出 (8);

[0075] Substituting formulas (5), (6), (7), and (8) into formula (4), we can obtain:

[0076]

[0077] For the air inlet mass flow rate m 空进 There are the following expressions:

[0078]

[0079] For a fixed model of fuel cell, the size of the flow field is fixed, and the air inlet gas pressure P 进 and air outlet gas pressure P 出 There is a certain relationship, which is expressed as follows:

[0080] P 进 =k*m 空进 +P 出 (11);

[0081] Where k is the stack resistance coefficient.

[0082] Partial pressure of water at air outlet P 水出 The coolant temperature T at the outlet of the stack cooling path 出 The details are as follows:

[0083] P 水出 =0.5124*T 出 -152.55 (12);

[0084] Substituting formulas (10), (11), and (12) into formula (9), we can obtain formula (1):

[0085]

[0086] The comparative RH 实际 and RH 目标 , adjust the humidity according to the comparison results, as follows:

[0087] When RH 实际 =RH 目标 When the current operating conditions are maintained;

[0088] When RH 实际 <RH 目标 When the air metering ratio λ remains unchanged, the back pressure valve opening is increased, the air compressor speed is reduced, and thus P 进 , until the target humidity is met; if P is reduced 进 to If the intake air humidity requirement is still not met, the cathode intake air flow rate is reduced, that is, the air stoichiometric ratio λ is reduced, thereby further reducing Until the target humidity is met;

[0089] When RH 实际 >RH 目标 When the air metering ratio λ remains unchanged, the back pressure valve opening is reduced, the air compressor speed is increased, and P is gradually increased. 进 , until the target humidity is met; if P is increased 进 to If the intake humidity requirement is still not met, set At this time, the highest humidity that can be controlled is reached.

[0090] The present application provides a mixing chamber at the rear end of the air compressor and uses an atomizer in the mixing chamber to humidify the air entering the stack, thereby replacing the traditional membrane humidifier and reducing the cost of the fuel cell. By providing an air compressor with two outlets, a small part of the high-temperature air compressed by the air compressor is used to flow out through the second outlet of the air compressor into the atomizer, and the liquid water in the atomizer is atomized into smaller droplets; while most of the high-temperature air flows out through the first outlet of the air compressor into the mixing chamber. In the mixing chamber, the high-temperature air flowing out of the first outlet of the air compressor is used to vaporize the droplets sprayed by the atomizer, and then evenly mix with the air to humidify the air entering the stack.

[0091] By setting up a water collecting tank to collect the liquid water separated by the water separator in the hydrogen supply subsystem, liquid water is provided to the atomizer, making full use of the water produced by the fuel cell stack to achieve self-humidification of the fuel cell; at the same time, the gas pressure P at the fuel cell stack inlet is determined by accurate calculation formula. 进 The value range of RH is set according to the working conditions. 目标 , get the humidity value RH fed back from the temperature and humidity sensor 实际 , compared with RH 实际 and RH 目标 , and humidity is adjusted based on the comparison results. By controlling the intake air flow and pressure through atomization humidification, active humidity adjustment is achieved under varying operating conditions. This not only helps to extend the life of the fuel cell stack and achieve better fuel cell stack water management, but also provides a solution for precise humidity control.

[0092] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A humidity control method for a fuel cell system based on atomization humidification, characterized in that: The fuel cell system comprises a fuel cell stack (4), a hydrogen supply subsystem, and an oxygen supply subsystem; The hydrogen supply subsystem comprises a hydrogen source (1), a proportional valve (2), an ejector (3), and a water separator (5); the hydrogen source (1) is sequentially connected to the proportional valve (2), the ejector (3), and the anode inlet of the fuel cell stack (4); the anode outlet of the fuel cell stack (4) is connected to the water separator (5); and the gas outlet of the water separator (5) is connected to the ejector (3); The oxygen supply subsystem comprises an air compressor (9), a mixing chamber (10), an atomizer (8), a spray water pump (7), and a water collecting tank (6); a first outlet of the air compressor (9) is connected to the mixing chamber (10) and the cathode inlet of the cell stack (4) in sequence; a second outlet of the air compressor (9) is connected to the gas inlet of the atomizer (8); the cathode outlet of the cell stack (4) is connected to the tail pipe; a liquid inlet of the water collecting tank (6) is connected to the liquid outlet of the water distributor (5); and a liquid outlet of the water collecting tank (6) is connected to the spray water pump (7), the atomizer (8), and the mixing chamber (10) in sequence; The humidity adjustment method is as follows: When the fuel cell system is running, the liquid water separated by the water separator (5) in the hydrogen supply subsystem enters the water collecting tank (6), and the liquid water in the water collecting tank (6) enters the atomizer (8) under the action of the spray water pump (7); The air is compressed by the air compressor (9) to produce high-temperature air, a small portion of which flows out through the second outlet of the air compressor (9) and enters the atomizer (8), and is used to atomize the liquid water in the atomizer (8) into smaller droplets; the majority of the high-temperature air flows out through the first outlet of the air compressor (9) and enters the mixing chamber (10), in which the droplets sprayed from the atomizer (8) are vaporized by the high-temperature air flowing out of the first outlet of the air compressor (9), and then uniformly mixed with the air, thereby humidifying the air entering the pile; Control the speed of the spray pump (7) to maintain P 雾化 -P 进 =20kPa, to ensure that the atomizer can continuously atomize, P 雾化 is the gas pressure in the pipeline between the spray water pump (7) and the atomizer (8), measured by a second pressure sensor (16) provided on the pipeline between the spray water pump (7) and the atomizer (8), P 进 is the gas pressure at the air inlet of the stack, measured by a first pressure sensor (15) arranged at the cathode inlet of the stack (4); When the air stoichiometric ratio λ remains unchanged, calculate the stack air inlet gas pressure P 进 The value range of is as follows: Calculate the maximum value of the stack air inlet gas pressure To maintain P 雾化 -P 进 =20kPa, P 雾化 Increase, P 进 As the speed of the atomizing water pump (7) reaches the maximum, P 雾化 Reaching the maximum value, corresponding to P 进 It also reaches the maximum value, that is, when the atomizing water pump (7) reaches the highest speed, the maximum value of the stack air inlet gas pressure is calculated. Calculate the minimum value of the stack air inlet gas pressure The calculation formula is as follows: Where, λ is the air stoichiometric ratio; k is the stack flow resistance coefficient; I is the stack operating current; N is the number of cells in the stack; F is the Faraday constant; M 空气 is the molar mass of air; T 出 is the coolant temperature at the outlet of the cooling path of the fuel cell stack; P 进 As the air stoichiometric ratio λ increases, for a fixed λ, the minimum value of the stack inlet gas pressure is calculated by formula (1): Stack air inlet gas pressure P 进 The value range is Adjust the air inlet humidity RH. For a fixed system, each operating point has an optimal humidity value. Set the target RH according to the operating conditions. 目标 , obtain the humidity value RH fed back from the temperature and humidity sensor (14) 实际 , compared with RH 实际 and RH 目标 , and adjust the humidity based on the comparison results.

2. The humidity control method according to claim 1, wherein: The comparative RH 实际 and RH 目标 , adjust the humidity according to the comparison results, as follows: When RH 实际 =RH 目标 When the current operating conditions are maintained; When RH 实际 <RH 目标 When the air metering ratio λ remains unchanged, the back pressure valve opening is increased, the air compressor speed is reduced, and thus P 进 , until the target humidity is met; if P is reduced 进 to If the intake air humidity requirement is still not met, the cathode intake air flow rate is reduced, that is, the air stoichiometric ratio λ is reduced, thereby further reducing Until the target humidity is met; When RH 实际 >RH 目标 When the air metering ratio λ remains unchanged, the back pressure valve opening is reduced, the air compressor speed is increased, and P is gradually increased. 进 , until the target humidity is met; if P is increased 进 to If the intake humidity requirement is still not met, set At this time, the highest humidity that can be controlled is reached.

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