CN117039057A - Fuel cell air system, fuel cell system, vehicle, and control method - Google Patents

Abstract

The application provides a fuel cell air system, a fuel cell system, a vehicle and a control method, the system is applied to the vehicle, and comprises: the system comprises an air compressor, a turbine generator, a first bypass loop, a second bypass loop, a first control unit, a second control unit, a first control unit and a second control unit, wherein the air compressor and the turbine generator are distributed, the first bypass loop is arranged between the air compressor and the turbine generator, the second bypass loop is arranged in the turbine generator, the first bypass loop is controlled to be opened when the fuel cell system is in a low-power generation working condition, and part of compressed air is discharged from the first bypass loop and a turbine runner; the first bypass circuit and/or the second bypass circuit are controlled to be opened when the fuel cell system is in a low-temperature cold start working condition, and the compressed air and/or the exhaust gas of the fuel cell is used for heating the rotating parts of the turbine generator. The system can be used for distributing the air compressor and the turbine generator, has high redundancy, and can be used for opening the bypass loop during low-temperature cold start, so that the compressed air and waste gas are utilized for heating and deicing, the cold start time is reduced, and the start failure caused by clamping stagnation of the turbine during cold start is effectively avoided.

Description

Fuel cell air system, fuel cell system, vehicle, and control method

Technical Field

The present application relates to the field of vehicles, and more particularly, to a fuel cell air system, a fuel cell system, a vehicle, and a control method in the field of vehicles.

Background

The cathode exhaust gas of the fuel cell for electrochemical power generation using hydrogen and oxygen (mainly, but not limited to, oxygen in air) as fuel still contains a certain amount of kinetic energy and thermal energy, and the exhaust gas mainly becomes water vapor (and a small amount of liquid water) and air (mainly, nitrogen) which does not participate in the reaction. The turbine recovers the energy in the waste heat, the residual pressure and the waste gas through expansion work, and converts the energy into mechanical energy to assist to drive the air compressor to compress air, so that the turbine is an important means and development direction for reducing the parasitic power consumption of the air system of the fuel cell (especially for retransmitting electric power).

At present, a fuel cell engine using an air compressor with energy recovery needs to wait for a turbine to break ice and then enter a power generation state after cold start is successful, the cold start time is too long, the operation economy is poor, and when turbine blades of the air compressor are worn or bent, broken, deteriorated and invalid due to cold start, the function of providing compressed air by the whole air compressor is lost, and a fuel cell system cannot work and has poor redundancy.

Disclosure of Invention

The application provides a fuel cell air system, a fuel cell system, a vehicle and a control method, wherein an air compressor and a turbine generator are distributed in the system, during low-temperature cold start, compressed air is directly supplied to a cathode of a galvanic pile by using the air compressor to realize quick start power generation, a turbine bypass loop bypasses waste gas of the cathode of the galvanic pile firstly, so that the waste gas does not directly enter a turbine impeller and flows into a runner of a bypass loop in a turbine shell, a rotating part of the turbine is heated, tail waste gas is switched to the turbine impeller after a heat engine for energy recovery, the cold start time is greatly shortened, the operation economy of the fuel cell system is improved, and the start failure caused by clamping stagnation in the cold start of the turbine of an integrated air compressor can be effectively avoided.

In a first aspect, there is provided a fuel cell air system comprising: an air compressor and a turbine generator arranged in a distributed manner; one end of the first bypass loop is connected with the air outlet of the air compressor, and the other end of the first bypass loop is connected with the turbine inlet of the turbine generator; a second bypass circuit connected in parallel with a turbine runner of the turbine generator; the control unit is used for controlling the first bypass loop to be opened when the fuel cell system is in a low-power generation working condition and discharging part of compressed air from the first bypass loop and the turbine runner; and when the fuel cell system is in a low-temperature cold start working condition, controlling the first bypass loop and/or the second bypass loop to be opened, and heating the rotating part of the turbine generator by using the compressed air and/or the exhaust gas of the fuel cell.

Through the technical scheme, the air compressor and the turbine generator are distributed, and can operate in respective high-efficiency areas according to the requirements of fuel cell power generation and cathode energy recovery so as to improve the overall efficiency of the fuel cell, and the air compressor can normally provide compressed air for the electric pile to maintain a power generation state without being influenced by the air compressor when the turbine generator fails, so that the redundancy is high, a bypass loop can be controlled to be opened during low-temperature cold start, the rotating parts of the turbine generator are heated by utilizing the compressed air and the waste gas of the fuel cell, the cold start time is greatly shortened, the operation economy of a fuel cell system is improved, and the start failure caused by clamping stagnation in the cold start of the turbine of the integrated air compressor can be effectively avoided.

With reference to the first aspect, in certain possible implementations, the second bypass circuit is disposed within a housing of the turbine generator.

With reference to the first aspect and the foregoing implementation manner, in some possible implementation manners, the first bypass circuit includes a first bypass valve, a first inlet flow passage and a first outlet flow passage, where the first bypass valve is connected to the first inlet flow passage and the first outlet flow passage, respectively, the first inlet circuit is further connected to an air outlet of the air compressor, and the first outlet flow passage is further connected to the turbine inlet.

Through the technical scheme, the first bypass loop in the embodiment of the application comprises the first bypass valve, the first inlet runner and the first outlet runner, wherein the first bypass valve is respectively connected with the first inlet runner and the first outlet runner and is used for controlling the discharge of high-temperature gas in the first bypass runner, the first inlet runner is also connected with the air outlet of the air compressor, and the first outlet runner is also connected with the inlet of the turbine, so that the subsequent gas circulation and recovery are facilitated.

With reference to the first aspect and the foregoing implementation manners, in some possible implementation manners, the second bypass circuit includes a second bypass valve, a second inlet flow passage, and a second outlet flow passage, where the second bypass valve is connected to the second inlet flow passage and the second outlet flow passage, respectively, and the second inlet circuit is further connected to the turbine inlet, and the second outlet flow passage is further connected to a turbine outlet of the turbine generator.

Through the technical scheme, the second bypass loop in the embodiment of the application comprises the second bypass valve, the second inlet runner and the second outlet runner, wherein the second bypass valve is respectively connected with the second inlet runner and the second outlet runner and is used for controlling the discharge of high-temperature gas in the second bypass runner, the second inlet runner is also connected with the air outlet of the air compressor, and the second outlet runner is also connected with the inlet of the turbine, so that the circulation and recovery of subsequent gas are facilitated.

In a second aspect, a fuel cell system is provided, including a fuel cell and a fuel cell air system according to an embodiment of the first aspect

In a third aspect, there is provided a vehicle comprising the fuel cell system of the second aspect.

In a fourth aspect, a control method of a fuel cell air system is provided, the method being used for controlling the fuel cell air system as in the first aspect or any implementation manner of the first aspect, wherein the method includes: identifying an actual condition of the fuel cell system; if the fuel cell system is identified to be in a low-power generation working condition, a first bypass loop of the air system is controlled to be opened, and part of compressed air is discharged from the first bypass loop and a turbine runner of the air system; and if the fuel cell system is identified to be in a low-temperature cold start working condition, controlling the first bypass loop and/or the second bypass loop of the air system to be opened, and heating the rotating part of the turbine generator by utilizing the compressed air and/or the exhaust gas of the fuel cell.

According to the technical scheme, when the air compressor is used for cold starting at low temperature, compressed air is directly supplied to the cathode of the electric pile to realize quick starting power generation, the second bypass loop bypasses the cathode waste gas of the electric pile, so that the waste gas does not directly enter the turbine impeller and flows into the flow passage of the bypass loop in the turbine shell, the turbine rotating part is heated, the air compressor is not required to be used for cold starting for a long time like the integral air compressor in the prior art, and the operation economy of the fuel cell system is improved when the turbine blade fails to start due to freezing clamping stagnation.

With reference to the fourth aspect, in some possible implementations, the identifying an actual operating condition of the fuel cell system includes: if the fuel cell system is in an operating state, when the generated power of the fuel cell system is smaller than a preset power, controlling the fuel cell system to enter the low-power generation working condition; and if the fuel cell system is in a closed state, controlling the fuel cell system to enter the low-temperature cold start working condition when the ambient temperature and the actual temperature of the turbine generator are both smaller than the corresponding preset temperature.

Through the technical scheme, the embodiment of the application can judge the freezing possibility by combining the ambient temperature with the actual temperature of the turbine generator, thereby improving the accuracy, and the threshold values of the ambient temperature and the actual temperature of the turbine generator can be set by technicians according to the characteristics of the system, thereby improving the flexibility.

With reference to the fourth aspect and the foregoing implementation manner, in some possible implementation manners, the controlling the opening of the first bypass circuit and/or the second bypass circuit of the air system includes: acquiring a target temperature at which a rotating component of the turbine generator can be unfrozen; determining a target opening of the first bypass circuit and/or a second bypass circuit of the air system based on a difference between the actual temperature and the target temperature; and controlling the first bypass loop and/or the second bypass loop to be opened to the target opening degree.

Through the technical scheme, the embodiment of the application can realize the control of the speed of the heating deicing process by adjusting the opening of the bypass loop through the difference value between the actual temperature and the target temperature, and the turbine generator is gradually switched into the power generation state through the second bypass loop.

With reference to the fourth aspect and the foregoing implementation manner, in some possible implementation manners, after controlling the first bypass loop and/or the second bypass loop to be opened to the target opening degree, the method further includes: detecting a duration of opening of the first bypass circuit and/or the second bypass circuit; if the duration is longer than the preset duration, reducing the current opening of the second bypass loop according to a preset step length so as to gradually increase the flow of the compressed air and/or the waste gas entering the turbine runner; and when the end condition of the low-temperature cold start working condition is met, controlling the first bypass loop and the second bypass loop to be closed.

Through the technical scheme, the embodiment of the application can judge whether the opening time of the bypass loop is longer than the preset time, if so, the current opening of the second bypass loop is reduced according to the preset step length so as to gradually increase the flow of compressed air and/or waste gas entering the turbine runner, and when the ending condition of the low-temperature freezing starting working condition is met, the bypass loop is controlled to be closed so as to realize the power generation state of the follow-up fuel cell air system.

Drawings

Fig. 1 is a schematic structural diagram of a fuel cell air system according to an embodiment of the present application;

FIG. 2 is a schematic illustration of a fuel cell air system provided in accordance with an embodiment of the present application;

fig. 3 is a schematic structural view of a fuel cell system according to an embodiment of the present application;

fig. 4 is a flowchart of a control method of the fuel cell air system provided in the embodiment of the present application;

FIG. 5 is a flow chart of a method for low temperature cold start determination provided by an embodiment of the present application;

FIG. 6 is a flow chart of a low temperature cold start control method provided by an embodiment of the present application;

FIG. 7 is a schematic diagram of a fuel cell air system at cold start at low temperature according to an embodiment of the present application;

FIG. 8 is a schematic diagram of a fuel cell air system before a cold start at low temperature is completed according to an embodiment of the present application;

FIG. 9 is a schematic diagram of a fuel cell air system in a conventional state provided by an embodiment of the present application;

fig. 10 is a schematic diagram of the opening of the bypass valve in the control method of the low-temperature cold start process according to the embodiment of the present application.

Detailed Description

The technical scheme of the application will be clearly and thoroughly described below with reference to the accompanying drawings. Wherein, in the description of the embodiments of the present application, unless otherwise indicated, "/" means or, for example, a/B may represent a or B: the text "and/or" is merely an association relation describing the associated object, and indicates that three relations may exist, for example, a and/or B may indicate: the three cases where a exists alone, a and B exist together, and B exists alone, and furthermore, in the description of the embodiments of the present application, "plural" means two or more than two.

The terms "first," "second," and the like, are used below for descriptive purposes only and are not to be construed as implying or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature.

Before explaining the air system of the fuel cell provided by the embodiment of the application, the structure and the existing problems of the integrated air compressor related to the related art are explained.

The principle of the integral air compressor for realizing air compression is as follows, in order to enhance the wear resistance and fracture resistance of the blades, the turbine impeller and the blades adopt matrix material reinforcement or/and coating process, the integral air compressor has an air compressor impeller with single-stage or two-stage compression function and a single-stage expansion turbine impeller, and the integral air compressor and a driving motor rotating shaft of the air compressor are arranged on the same rotating shaft together with other necessary parts, and the integral air compressor keeps the same physical rotating speed during working. The air compressor compresses fresh air, and the compressed fresh air is cooled by an intercooler and humidified by a humidifier and then is sent to a cathode inlet of the electric pile. The waste heat and residual pressure waste gas at the cathode outlet of the electric pile contains a large amount of water vapor and liquid drops, so as to prevent the large liquid drops from impacting the turbine impeller and blades rotating at high speed to cause failure, then the liquid water is separated by the gas-liquid separator and enters the single-stage turbine, the waste heat and residual pressure waste gas pushes the turbine blades of the turbine to rotate at high speed and then flows out of the turbine to be discharged to a tail row main pipeline, the energy recovery and reutilization of the waste gas at the cathode outlet of the electric pile are realized, and the kinetic energy and the heat energy are converted into rotary mechanical energy to assist the coaxial motor to drive the air compressor impeller to compress air, thereby reducing the power consumption of the motor.

However, the working environment temperature of the air compressor of the fuel cell for the vehicle is usually between minus 40 ℃ and minus 65 ℃, the water content in the residual heat and residual pressure exhaust gas at the cathode outlet of the electric pile is high, the relative humidity is generally above 85%R.H., a large amount of liquid water in the form of liquid drops is generated by condensation along the pipe wall in the working process, a certain amount of liquid water remains in the turbine shell and after the turbine impeller and blades are stopped, the liquid water in the turbine is frozen in the low-temperature environment at low environment temperature, particularly at low-temperature cold start, so that the turbine impeller and the turbine shell are blocked, the air compressor motor cannot normally drive the impeller to rotate, and the cold start of the air compressor is caused to be faulty.

The scheme for solving the cold start of the air compressor at present mainly comprises the following steps:

(1) Adopts the scheme of gas-liquid separator and shutdown purging: a gas-liquid separator is arranged in front of the inlet of the turbine to separate part of liquid water, and the purging of the pile before the shutdown is also helpful for removing a certain amount of liquid water.

However, a part of liquid water and water vapor still enter the turbine to freeze in a low-temperature environment, so that the turbine impeller and the turbine shell are stuck, and the air compressor motor cannot normally drive the impeller to rotate, so that the cold start fault of the air compressor is caused.

(2) An auxiliary cold start scheme for heating and melting ice: a hot water jacket is added in the turbine shell or on the surface of the turbine shell, and hot water heated by a PTC heater (Positive Temperature Coefficient, positive temperature coefficient resistance heater) of the fuel cell system is introduced for preheating the turbine shell during cold start; or PTC heating belts and other induction heating methods are used for heating the surface or the interior of the turbine shell to realize the purpose of ice melting cold start.

However, the scheme needs to additionally add devices and/or pipelines for heating, so that the complexity and the cost of the system are increased, and the heating time is long; liquid water and/or ice residue remaining on and/or near the blades after ice melting causes secondary damage after rotation of the impeller.

(3) Scheme of direct cold start: the direct cold start is realized by optimizing a low-temperature cold start strategy of the air compressor controller driving motor, such as increasing start torque, shaking of a motor rotor and other ice breaking methods.

However, the turbine blade abrasion caused by slight freezing in the scheme can lead to performance attenuation after the air compressor is operated; the turbine blades are bent and broken caused by severe freezing, the dynamic balance of rotor components of the air compressor is damaged, the whole air compressor is finally caused to fail, and the base material is adopted to strengthen or/and coat the process impeller and the turbine of the blades, so that the service life is still short, and the requirements of a fuel cell power generation system can not be met.

In addition, the fuel cell engine using the integrated air compressor needs to wait for the turbine to enter a power generation state after the successful cold start, the cold start time is too long, the running economy is poor, and the air compressor impeller and the turbine of the integrated air compressor are arranged on a shaft. The actual running condition of working on the vehicle is complex and changeable, the turbine blade which is worn or bent and broken due to cold start is continuously deteriorated, the dynamic balance of the rotor component of the air compressor is damaged, the air bearing is worn, the whole air compressor is finally caused to fail, the fuel cell system cannot continue to normally generate electricity and work due to no fresh compressed air supply, the working capacity can be recovered after the whole air compressor is replaced again, and the redundancy is poor.

Fig. 1 is a schematic structural diagram of an air system for a fuel cell according to an embodiment of the present application.

Illustratively, as shown in FIG. 1, the fuel cell air system 100 includes: a distributed air compressor 11, a distributed turbine generator 12, a first bypass circuit 13, a second bypass circuit 14 and a control unit 15.

One end of the first bypass loop 13 is connected with an air outlet of the air compressor 11, and the other end of the first bypass loop 13 is connected with an inlet of a turbine 12 of the turbine generator; the second bypass circuit 14 is connected in parallel with the turbine runner of the turbine generator; the control unit 15 is used for controlling the first bypass loop 13 to be opened when the fuel cell system is in a low-power generation working condition, and discharging part of compressed air from the first bypass loop 13 and the turbine runner; when the fuel cell system is in a cold start condition at low temperature, the first bypass circuit 13 and/or the second bypass circuit 14 are controlled to be opened, and the compressed air and/or the exhaust gas of the fuel cell is used for heating the rotating parts of the turbine generator 12.

The first bypass circuit may be an air compressor bypass circuit, and the second bypass circuit may be a turbine bypass circuit.

It can be understood that the air compressor and the turbine generator in the embodiment of the application are distributed and arranged, are not in a coaxial structure, and are not limited by the limitation of the same physical rotation speed of the air compressor and the turbine in the integrated air compressor with the coaxial structure in the prior art when the rotor works, so that the air compressor can be arranged in a higher aerodynamic efficiency area to operate, thereby being more beneficial to reducing the parasitic power consumption of the air system of the fuel cell and improving the operation reliability and economy of the fuel cell system, and the air compressor and the turbine generator can operate in respective high-efficiency areas according to the requirements of power generation and cathode energy recovery of the fuel cell so as to improve the overall efficiency of the fuel cell.

When the fuel cell system is in a low-power generation working condition, the first bypass loop is controlled to be opened, and part of compressed air is discharged from the first bypass loop and the turbine runner and used for preventing the surge of the air compressor and the concentration dilution of hydrogen in the tail calandria in the start-stop and idle stages; when the fuel cell system is in a low-temperature cold start working condition, the first bypass loop and/or the second bypass loop is controlled to be opened, the second bypass loop or the first bypass loop and the second bypass loop can be opened at the same time, the compressed air and/or the waste gas of the fuel cell are further utilized to heat the rotating part of the turbine generator, the air compressor directly provides the compressed air required by power generation for the cathode of the electric pile, so that the fuel cell power generation system directly enters a normal power generation state, the integral air compressor in the prior art does not need to wait for the successful cold start of the turbine after the ice breaking of the turbine, normal power generation is realized, the mixed gas of the waste heat and the waste gas in the cathode outlet of the electric pile of the fuel cell and the high-temperature compressed air at the outlet of a small part of the air compressor from the bypass loop of the air compressor is realized, and the pressure loss resistance is larger, so that the residual liquid water and/or the ice slag are fully blown off to avoid secondary damage to the impeller, the waste gas is conveniently switched to the turbine impeller to be expanded and work and power generated, the energy is greatly reduced, the time of starting the fuel cell is greatly shortened, and the economic performance of the integral air compressor system is prevented from failing to start the cold start.

The air compressor in the embodiment of the application is of a two-stage compression structure, and the independent turbine generator is used for recycling the energy of the tail discharge waste heat and the residual pressure of the electric pile and reducing the parasitic power consumption of the air system of the fuel cell; when the turbine generator has faults like turbine blade failure, the air compressor is not affected by the faults, compressed air can still be normally supplied to the electric pile to maintain the power generation state, and the redundancy is high.

In an embodiment of the present application, the second bypass circuit 14 is disposed within the housing of the turbine generator 12.

In the embodiment of the present application, the first bypass circuit 13 includes a first bypass valve, a first inlet flow passage and a first outlet flow passage, wherein the first bypass valve is connected to the first inlet flow passage and the first outlet flow passage, respectively, the first inlet flow passage is further connected to an air outlet of the air compressor, and the first outlet flow passage is further connected to an inlet of the turbine.

The first bypass valve may be an air compressor bypass valve, the first inlet flow passage may be an air compressor bypass valve inlet flow passage (may also be referred to as an air compressor bypass valve inlet pipe), and the first outlet flow passage may be an air compressor bypass valve outlet flow passage (may also be referred to as an air compressor bypass valve outlet pipe).

In an embodiment of the present application, the second bypass circuit 14 includes a second bypass valve, a second inlet flow passage and a second outlet flow passage, wherein the second bypass valve is connected to the second inlet flow passage and the second outlet flow passage, respectively, and the second inlet flow passage is further connected to the turbine inlet and the second outlet flow passage is further connected to the turbine outlet of the turbine generator.

The second bypass valve may be a turbine bypass valve, the second inlet flow passage may be a turbine bypass circuit inlet flow passage, and the second outlet flow passage may be a turbine bypass circuit outlet flow passage.

The fuel cell air system of the present application will be described with reference to fig. 2, and the fuel cell air system 10 includes: the fuel cell cathode intake system 20, the air compressor 25, the air compressor motor controller 26, the air compressor bypass circuit 27, the intercooler 28, the humidifier 29, the fuel cell stack 32, the high-voltage DC/DC 33 (high-voltage DC converter) (hereinafter simply referred to as "DC/DC"), the turbo generator inverter 34, the turbo generator 35, the fuel cell cathode exhaust system 41, and the fuel cell control unit FCU 42 (Fuel cell Control Unit ) (hereinafter simply referred to as "FCU").

The fuel cell cathode intake system 20 includes: the air intake filter 21, the air intake pressure sensor 22, the air intake temperature sensor 23, the air intake flow sensor 24, the air compressor 25, the air compressor motor controller 26, the intercooler 28, the dry side of the humidifier 29 (dry air passage between the dry inlet port 29a to the dry outlet port 29b of the humidifier 29 and the two located inside 29), the in-stack air pressure sensor 30, the in-stack air temperature sensor 31, and the on-way piping. The fuel cell cathode gas inlet system 20 supplies cathode gas (mainly fresh air but not limited to air) to the fuel cell stack 32.

The air intake temperature sensor 23 measures the temperature T1c of the intake air, and a measurement signal is sent to the FCU.

The air compressor 25 compresses fresh air (mainly fresh air but not limited to air) as cathode gas to be sent to the cathode of the fuel cell stack for electrochemical reaction by driving the air compressor impeller to rotate by a high-speed motor. The air compressor 25 is a two-stage compressor using an air bearing. The air compressor 25 includes an air compressor inlet 25a, a low-pressure stage air compressor 251, an air compressor thrust air bearing 252, an air compressor rotor shaft 253, a high-pressure stage air compressor 254 (here and in the present application, "high pressure" at the gas declaration means high pressure of the gas), an air compressor radial air bearing 255, an air compressor motor 256, an air compressor inter-stage pipe 257, and an air compressor outlet 25b, which are physically assembled into one unit.

The compressed air pressure and temperature rise, and the compressor outlet 25b is connected to the front end of an air compressor bypass circuit 27 described below. The air compressor 25 and the turbine generator 35 of the present application are arranged in a split type: the non-coaxial structure, the rotor is not limited by the limitation of the same physical rotation speed of the air compressor and the turbine in the integrated air compressor with the coaxial structure in the prior art, so the air compressor 25 can be arranged in a higher aerodynamic efficiency area to operate, thereby being more beneficial to reducing the parasitic power consumption of the air system of the fuel cell and improving the operation reliability and economy of the fuel cell system.

The air compressor motor controller 26 converts the high-voltage direct current output by the DC/DC into high-voltage high-frequency alternating current through a high-power semiconductor component so as to drive the air compressor motor 256 to rotate and work, adjusts the rotating speed and power of the air compressor motor according to the communication instruction of the FCU, and sends the running state to the FCU in real time.

The intercooler 28 cools the air having a temperature increased after compression by the air compressor 25 down to the cathode gas requirement of the stack. The intercooler is typically a water-cooled intercooler (other cooling mediums may also be employed), the cooling medium circuit and system of which are not set forth in the present application. The inlet of the intercooler 28 is connected to the air compressor outlet 25b of the air compressor 25. The outlet of the intercooler 28 is connected to a dry inlet port 29a of the humidifier 29.

The humidifier 29 humidifies the dry air supplied from the air compressor 25 into the stack by using the wet air discharged from the cathode of the fuel cell stack 32 to satisfy the humidity requirement of the electrochemical reaction of the stack, thereby ensuring higher reaction efficiency.

The fuel cell stack 32 is a device for electrochemically reacting a cathode gas and an anode gas to generate electric power, and is formed by stacking a plurality of single cell channels in a certain process. The main emissions of the fuel cell stack are water and nitrogen, wherein the cathode exhaust gas contains higher residual heat and residual energy, and the turbine generator 35 in the application generates electricity by recovering the residual heat and residual energy in the cathode exhaust gas. The cathode gas of the fuel cell stack 32 is introduced through a cathode gas inlet 32a, and the cathode gas inlet 32a is connected to a dry-out port 29b of the humidifier 29. The cathode off-gas of the fuel cell stack 32 is taken out through a cathode gas outlet 32b, and the cathode gas outlet 32b is connected to a wet inlet port 29c of the humidifier 29.

The high-voltage DC/DC 33 converts the unstable direct current with lower voltage generated and output by the fuel cell stack into a stable voltage value, and outputs the stable voltage value to the direct current bus for electric equipment.

The fuel cell cathode exhaust system 41 discharges the cathode exhaust gas from the fuel cell stack 32 to the atmosphere or other device. The fuel cell cathode exhaust system 41 is provided with the wet side of the humidifier 29 (wet inlet port 29c to wet outlet port 29d of the humidifier 29 and a wet passage therebetween within the humidifier 29), the air compressor bypass circuit 27, the turbo generator inverter 34, the turbo generator 35, the tail pipe 39, the tail pipe muffler 40, and the on-way piping.

The air compressor bypass circuit 27 bypasses a small part of compressed air at the outlet of the air compressor 25 to the turbine inlet 35a of the turbine generator 35 during low-power generation or low-temperature cold start, and finally is discharged to the atmosphere or other devices through the tail exhaust pipe, the bypass during low-power generation is mainly used for preventing the surge of the air compressor, and the dilution of the hydrogen concentration in the tail exhaust pipe during start-stop and idle stages, the bypass during low-temperature cold start aims to heat the rotating parts of the turbine 37 by using the high-temperature gas at the outlet of the air compressor to shorten the cold start time and avoid the freezing clamping stagnation of turbine blades, and the air bypass flows of the two working conditions are regulated by the air compressor bypass valve 272 arranged in the air compressor bypass circuit 27, and the opening degree of the air compressor bypass valve 272 is controlled by the FCU. The air compressor bypass circuit 27 includes an air compressor bypass valve inlet line 271, an air compressor bypass valve 272, and an air compressor bypass valve outlet line 273. The front end of the air compressor bypass circuit 27 is connected to the air compressor air outlet 25b of the air compressor 25 through an air compressor bypass valve inlet line 271, and the rear end of the air compressor bypass circuit 27 is connected to the turbine inlet 35a of the turbine 35 through an air compressor bypass valve outlet line 273.

The turbine generator inverter 34 (herein, the turbine generator inverter may also be referred to as a turbine generator controller) converts the high-voltage and high-frequency ac power output by the turbine generator 35 into high-voltage dc power through a high-power semiconductor component, and outputs the high-voltage dc power to the dc bus for use by the electric equipment; and adjusts the rotation speed and power of the turbine generator 35 according to the communication command of the FCU and transmits the operation state to the FCU in real time.

The turbine generator 35, the waste heat, residual pressure and waste gas in the cathode outlet of the fuel cell stack 32 flow through the turbine 37 to expand and do work to drive the motor 360 of the high-speed turbine generator to rotate to generate high-voltage and high-frequency alternating current, and then the high-voltage and high-frequency alternating current is converted into high-voltage direct current through the turbine generator inverter 34 and is output to a direct current bus for electric equipment to use, namely, the gas kinetic energy and the heat energy are firstly converted into shaft output rotary mechanical energy and finally converted into electric energy to be output, and the originally wasted waste gas energy is recovered, so that the hydrogen consumption of the fuel cell is reduced, and the method has important significance in the aspects of saving energy and protecting the environment.

In the application, the turbine generator 35 with the function of recovering the energy of the waste gas and the air compressor 25 for providing the compressed air for the fuel cell stack 32 adopt a split type structure, and the rotor with a non-coaxial structure is not limited by the limitation of the same physical rotation speed of the air compressor and the turbine in the integrated air compressor with the coaxial structure in the prior art when working, so that the independent turbine generator 35 is arranged according to the characteristic of the energy of the waste gas of the fuel cell stack, so that the turbine generator 35 operates at the optimal speed ratio to obtain the highest pneumatic efficiency of the turbine, and the energy of the waste heat and the residual pressure of the tail of the stack is recycled to obtain more generated energy, thereby further improving the overall efficiency and the economical efficiency of the fuel cell power generation system. The turbine generator 35 includes a turbine inlet 35a, a turbine housing temperature sensor 358, a turbine 37, a turbine generator motor 360, a turbine rotor shaft 361, a turbine bearing 362, and a turbine outlet 35b, which are physically assembled into a single unit. The gas flows into a gas channel of the turbine generator 35 through the turbine inlet 35a, the gas flows through the turbine 37 to expand, do work and output rotary mechanical energy to drive a motor 360 of the turbine generator to generate high-voltage high-frequency alternating current and output the high-voltage high-frequency alternating current to the turbine generator inverter 34 through the power interface, and the expanded and done gas is discharged to the tail gauntlet 39 through the turbine outlet 35 b.

It should be noted that: the "gas" may be a mixture of the residual heat, the residual pressure and the exhaust gas in the cathode outlet of the fuel cell stack 32 at the time of cold start at low temperature in the control method described below and a small part of the compressed air in the outlet of the air compressor 25 bypassed by the air compressor bypass circuit 27, or the residual heat, the residual pressure and the exhaust gas in the cathode outlet of the fuel cell stack 32 at the time of normal state in the control method described below. A turbine housing temperature sensor 358 is disposed in the turbine housing 38, described below, near the working interface of the adjustable turbine nozzle 357 and/or the turbine wheel 359 to measure the volute temperature T3 for condition determination at cold start at low temperature in the control method described below, the signal of the turbine housing temperature sensor 358 being connected to the turbine generator inverter 34. The turbine 37 includes a turbine wheel 359, a turbine housing 38, an adjustable turbine nozzle 357, and an adjustable turbine nozzle electric actuator 355. The turbine 37 recovers kinetic energy and thermal energy in the "gas" by expansion work, and transmits the recovered rotational mechanical energy to the motor 360 of the turbine generator through the turbine rotor shaft 361 for power generation.

The turbine 37 is of an adjustable structure, and the sectional area (i.e., opening) of the gas flow is changed by driving the adjustable turbine nozzle 357 through the adjustable turbine nozzle electric actuator 355. The adjustable turbine nozzle electric actuator 355 is drive controlled by the FCU and sends operating conditions to the FCU in real time. The turbine housing 38 includes a turbine inlet flow passage 351, a turbine flow passage 363, a turbine outlet flow passage 356, and a turbine bypass circuit 36. The turbine inlet flow passage 351 is connected to the turbine inlet 35a to introduce "gas" while being in parallel with the turbine bypass circuit inlet flow passage 352 of the turbine bypass circuit 36. The turbine outlet flow passage 356 is used for the discharge of the expanded gas, is connected to the turbine outlet 35b and eventually is discharged to the atmosphere or other device along the tail stack of the fuel cell air system, and is connected in parallel with the turbine bypass circuit outlet flow passage 354 of the turbine bypass circuit 36. The turbine runner 363 houses and accommodates the turbine wheel 359 and the adjustable turbine nozzle 357 therein, and collects and uniformly supplies the above-described "gas" to both.

The turbine bypass circuit 36 includes a turbine bypass circuit inlet flow passage 352, a turbine bypass valve 353, and a turbine bypass circuit outlet flow passage 354, and the turbine bypass circuit inlet flow passage 352 and the turbine bypass circuit outlet flow passage 354 are collectively referred to as a turbine bypass flow passage. During low-temperature cold start, the turbine bypass circuit 36 is opened by the turbine bypass valve 353, and the mixed gas of the residual heat and residual pressure exhaust gas in the cathode outlet of the fuel cell stack 32 and the high-temperature compressed air at the outlet of a small part of the air compressor 25 bypassed by the air compressor bypass circuit 27 is introduced into the turbine bypass flow passage to heat and deice the turbine rotating component (the turbine impeller 359 and the adjustable turbine nozzle 357), and after the heat engine is completed, the turbine bypass valve 353 is closed according to the conventional state in the control method to switch the exhaust gas to the turbine impeller to perform expansion work power generation to realize energy recovery.

It is emphasized that the turbine housing 38 includes the turbine inlet flow passage 351, the turbine flow passage 363, the turbine outlet flow passage 356, and the turbine bypass flow passage in the turbine bypass circuit 36 as a unitary component (which may be of integrally cast or assembled construction) for rapid deicing of the turbine rotating components by the bypass gas during cold start at low temperature, while the turbine housing temperature sensor 358 is disposed within the turbine housing 38. The opening degree of turbine bypass valve 353 is controlled by FCU in accordance with the control method described below.

The tail stack 39 interfaces with the turbine outlet 35b for collection of the fuel cell cathode exhaust while small amounts of hydrogen exiting the anode side also enter the tail stack at this stage where they are mixed with the cathode exhaust for dilution, ready for discharge into the atmosphere or other means.

A tail pipe muffler 40 mounted in the tail pipe 39 for reducing or eliminating noise of the cathode exhaust of the fuel cell.

The fuel cell control unit FCU 42, an electronic control unit composed of a microprocessor, an access memory, a plurality of driving units, and input/output ports, is responsible for the functional control of the fuel cell air system 10 and other systems not mentioned in the present invention. The FCU reads status feedback signals from sensors and actuators (e.g., valves) such as temperature, pressure, flow, etc. in the fuel cell air system 10 and other systems not mentioned herein. In addition, the FCU sends control commands to the air compressor motor controller 26 and the turbine generator inverter 34 through the communication bus to regulate the rotation speed and power of the motor, so as to respectively realize the functions of providing the required compressed air to the fuel cell stack 32 by the air compressor 25 and recovering the cathode exhaust gas by the turbine generator 35 to generate electricity, and simultaneously read the feedback signals of the air compressor motor controller 26 and the turbine generator inverter 34 and perform safety and fault management. The FCU sends drive or control signals to the air compressor bypass valve 272 in the air compressor bypass circuit 27, the turbine bypass valve 353 in the turbine bypass circuit 36, the adjustable turbine nozzle electric actuator 355 of the turbine 37, and other executing components of the fuel cell power generation system.

The FCU performs the following control method according to the present application. The atmospheric pressure sensor 43 measures the atmospheric pressure P0 of the place where the fuel cell air system 10 is located, the atmospheric ambient temperature sensor 44 measures the local ambient temperature T0, and the atmospheric pressure sensor 43 and the atmospheric ambient temperature sensor 44 are generally disposed inside the FCU, or may be disposed outside the FCU to send signals to the FCU for reading.

It should be noted that, some fuel cell stacks with self-humidification do not use an external humidifier 29, and the requirements of the stack operation on humidity can be met through the self-humidification inside the stack; the turbine 37 recovers kinetic energy and heat energy in the cathode waste heat and residual pressure exhaust gas and converts the kinetic energy and heat energy into rotary mechanical energy to drive the motor 360 of the turbine generator to generate electricity, and besides, the turbine can also drive a load with a certain torque type to realize conversion output of recovered energy; the turbine 37 may also take the form of a non-adjustable structure, i.e. a fixed section; the air compressor 25 may also adopt a single-stage compression structure, and may also meet the requirement of providing compressed air for the fuel cell stack 32; the intercooler 28 is a water-cooled intercooler, and an air-to-air heat exchanger 3 located in the integrated cooler 4 may also be used to raise the gas temperature at the turbine inlet to achieve that the exhaust gas entering the turbine does not contain liquid water.

According to the fuel cell air system provided by the application, the air compressor and the turbine generator are distributed, and can operate in respective high-efficiency areas according to the requirements of fuel cell power generation and cathode energy recovery so as to improve the overall efficiency of the fuel cell, and the air compressor can normally provide compressed air for the electric pile to maintain a power generation state without being influenced by the turbine generator when the turbine generator fails, so that the redundancy is high, one or more of the first bypass loop and the second bypass loop can be controlled to be opened during low-temperature cold start, and the waste gas of the fuel cell is used for heating the rotating parts of the turbine generator, so that the cold start time is greatly shortened, the operation economy of the fuel cell system is improved, and the start failure caused by clamping stagnation in the cold start of the turbine of the integrated air compressor can be effectively avoided.

The embodiment of the present application also provides a fuel cell system 200, as shown in fig. 3, including a fuel cell 201 and a fuel cell air system 100.

The embodiment of the application also provides a vehicle including the fuel cell system 200 as above.

Fig. 4 is a schematic flow chart of a control method of an air system of a fuel cell according to an embodiment of the present application.

Illustratively, as shown in fig. 4, the method is applied to control the above-described fuel cell air system, and includes the steps of:

in step S101, the actual operating conditions of the fuel cell system are identified.

In an embodiment of the present application, identifying an actual operating condition of a fuel cell system includes: if the fuel cell system is in an operating state, when the generated power of the fuel cell system is smaller than the preset power, controlling the fuel cell system to enter a low-power generating working condition; and if the fuel cell system is in a closed state, controlling the fuel cell system to enter a low-temperature cold start working condition when the ambient temperature and the actual temperature of the turbine generator are both smaller than the corresponding preset temperatures.

The preset power and the preset temperature can be set according to specific conditions, and are not particularly limited.

It can be understood that when the fuel cell system is in an operation state and when the generated power of the fuel cell system is smaller than the preset power, the embodiment of the application controls the fuel cell system to enter a low-power generating working condition; and when the fuel cell system is in a closed state and the ambient temperature and the actual temperature of the turbine generator are less than the corresponding preset temperatures, controlling the fuel cell system to enter a low-temperature cold start working condition.

It should be noted that, in the embodiment of the application, the freezing possibility is determined by combining the low-temperature freezing threshold temperature t0_min (ambient temperature) and the volute freezing threshold temperature t3_min (actual temperature of the turbine generator), so that the accuracy is improved, and the low-temperature freezing threshold temperature t0_min and the volute freezing threshold temperature t3_min can be set by technicians according to the characteristics of a system, so that the flexibility is improved.

Specifically, as shown in fig. 5, a method for determining a cold start of a fuel cell system will be described with reference to fig. 2, and the method includes the steps of:

step S210: the fuel cell power generation system is initialized.

Step S220: the FCU reads the atmospheric temperature sensor 44 to obtain the ambient temperature T0.

Step S230: comparing T0 with the low-temperature freezing threshold temperature T0_min, judging whether T0 is smaller than T0_min, if T0 is smaller than T0_min, executing steps S240-S300, otherwise executing step S270.

It should be noted that, the low-temperature freezing threshold temperature t0_min is a key criterion for judging whether the rotating component of the turbine generator 35 is frozen due to the too low environmental temperature, and t0_min needs to be set according to different fuel cell air systems and arrangement characteristics of the turbine generator, and in the control method of the present application, t0_min is set to 5 ℃, but may be set to other temperatures by a technician according to the characteristics of the system.

Step S240: the FCU reads the scroll temperature T3.

It should be noted that, in order to avoid a situation: the fuel cell power generation system has been in a low temperature environment (t0 < t0_min) for a considerable period of time, the temperature of the turbine contained in the cathode exhaust system of the fuel cell has been kept at a high temperature, and the possibility of freezing is unlikely to occur in a short period of time.

Step S250: and judging the volute temperature and T3, comparing the volute temperature with the volute freezing threshold temperature T3_min to confirm the freezing possibility, if T3 is smaller than T3_min, executing the step S260, otherwise executing the step S270.

The t3_min also needs to be set according to the arrangement characteristics of different fuel cell air systems and turbine generators, and in the control method of the application, the t3_min is set to 15 ℃, and can be set to any other temperature according to the characteristics of the system by technicians to achieve the same purpose.

Step S260: and judging that cold start control is needed, and entering a low-temperature cold start state.

Step S300: and (5) performing low-temperature cold start treatment.

In step S102, if it is identified that the fuel cell system is in the low power generation condition, the first bypass circuit of the air system is controlled to be opened, and a part of the compressed air is discharged from the first bypass circuit and the turbine runner of the air system.

It can be understood that if the embodiment of the application recognizes that the fuel cell system is in the low-power generation working condition, the first bypass loop of the air system is controlled to be opened, and part of compressed air is discharged from the first bypass loop and the turbine runner of the air system, so that the fuel cell system directly enters the normal power generation state, the economy and the efficiency are improved, and the power generation state can be entered after the integrated air compressor in the prior art waits for the successful cold start of the turbine ice breaking.

In step S103, if it is recognized that the fuel cell system is in the cold start condition, the first bypass circuit and/or the second bypass circuit of the air system are controlled to be opened, and the compressed air and/or the exhaust gas of the fuel cell is used to heat the rotating parts of the turbine generator.

It can be appreciated that if the embodiment of the application recognizes that the fuel cell system is in the low-temperature cold start working condition, the first bypass loop and the second bypass loop of the air system are controlled to be opened, and one or more of the compressed air and the exhaust gas of the fuel cell is used for heating the rotating part of the turbine generator, so as to realize heating and ice melting of the rotating part of the turbine.

In an embodiment of the application, controlling the opening of the first bypass circuit and/or the second bypass circuit of the air system comprises: acquiring a target temperature at which a rotating component of the turbine generator can be unfrozen; determining a target opening of the first bypass circuit and/or a second bypass circuit of the air system based on a difference between the actual temperature and the target temperature; and controlling the first bypass loop and/or the second bypass loop to be opened to a target opening degree.

The target temperature may be a preset temperature, or may be set according to specific conditions.

It can be understood that in the embodiment of the application, the target opening degrees of the first bypass loop and the second bypass loop are determined by calculating the difference value between the actual temperature and the target temperature of the turbine generator, and the first bypass loop and the second bypass loop are further controlled to be opened to the target opening degrees, wherein the first bypass loop and the second bypass loop are opened through respective bypass valves.

It should be noted that, the technician can set these two openings in detail according to different system characteristics and power generation related requirements.

In an embodiment of the present application, after controlling the first bypass circuit and/or the second bypass circuit to be opened to the target opening degree, the method further includes: detecting a duration of opening of the first bypass circuit and/or the second bypass circuit; if the duration time is longer than the preset duration time, the current opening of the second bypass loop is reduced according to the preset step length so as to gradually increase the flow of compressed air and/or waste gas entering the turbine runner; and when the end condition of the low-temperature cold start working condition is met, the first bypass loop and the second bypass loop are controlled to be closed.

The preset duration can be set according to specific conditions.

It may be appreciated that in the embodiment of the present application, after the first bypass loop and/or the second bypass loop are controlled to be opened to the target opening, the duration of the opening of the bypass loop may be detected, if the duration is greater than the preset duration, the current opening of the second bypass loop is reduced according to the preset step length, so as to gradually increase the flow of the compressed air, the exhaust gas, the compressed air and the exhaust gas entering the turbine runner, and when the ending condition of the low-temperature cold start working condition is satisfied, that is, when t3> t3_min, the first bypass loop and the second bypass loop are controlled to be closed.

The following will describe a control method for the low-temperature cold start working condition treatment with reference to fig. 2, specifically including the following steps, as shown in fig. 6:

step S310: FCU calculates the opening degrees of air compressor bypass valve 272 and turbine bypass valve 353 from the difference between T3 and t3_min.

The opening degree of the air compressor bypass valve 272 determines how small amount of high-temperature compressed air will bypass the turbine bypass circuit 36 along the air compressor bypass circuit 27, and the turbine rotating member (the turbine wheel 359 and the adjustable turbine nozzle 357) is heated and de-iced, i.e. the process time of heating and de-icing is determined, and at the same time, too much bypass amount will also lose the gas flow and pressure to have a certain effect on the normal power generation in step S340 described below; when T3 is much lower than t3_min (i.e., the freezing is considered to be more severe at this time), the openings of the air compressor bypass valve 272 and the turbine bypass valve 353 may be set to be fully opened to shorten the heating deicing process time, as shown in fig. 7, which is a schematic diagram of the fuel cell air system when the freezing is more severe; the technician can set the two opening degrees in detail according to different system characteristics and power generation related requirements, so that the flexibility of the low-temperature cold start process is improved.

Step S320: the FCU drives the air compressor bypass valve 272 to a specified opening.

Step S330: turbine bypass valve 353 is driven to a specified opening degree.

Step S340: the FCU controls the air compressor 25 to a specified rotational speed according to the power generation related requirements to supply the gas required for power generation to the cathode of the fuel cell stack, and the fuel cell power generation system starts to directly enter a normal power generation state.

The control method of the application improves economy and efficiency, and can enter a power generation state after the integral air compressor waits for successful cold start of the turbine ice breaking like the prior art. Meanwhile, the high-temperature compressed air at the outlet of the air compressor 25 is bypassed to the turbine bypass loop 36 through the air compressor bypass loop 27 and mixed with the waste heat, residual pressure and waste gas at the cathode outlet of the fuel cell stack 32 to heat and melt ice on the turbine rotating parts (the turbine impeller 359 and the adjustable turbine nozzle 357), and residual liquid water and/or ice residues are fully blown off to avoid secondary damage to the impeller.

Step S350: the FCU again reads the scroll temperature T3.

Step S360: and comparing T3 with T3_min to judge whether the low-temperature cold-start heating deicing process is finished, if T3< T3_min indicates that the heating deicing is still needed to be continued, returning to step S310, and at the moment, the FCU can recalculate the opening degrees of the new air compressor bypass valve 272 and the new turbine bypass valve 353 according to the current temperature value of T3. If T3> T3_min and remains for a period of time indicating that the heating deicing is complete, then step S370 is performed.

After several cycles S310 to S360 in the control method of the present application, the opening of the turbine bypass valve 353 is gradually turned off to introduce the gas into the turbine 37 to blow off the liquid water and/or the ice residue remaining in the adjustable turbine nozzle 357, the turbine wheel 359, the turbine runner 363, so as to avoid the secondary damage to the rotating wheel after the turbine generator 35 is started, and the turbine 37 does not rotate; after the residual liquid water and/or the ice slag is sufficiently blown off (calibration judgment can be performed by a delay method or the like), the opening of the turbine bypass valve 353 is continuously turned off to drive the turbine generator 35 to cut into a power generation state (the power generation power of the turbine generator 35 is lower in the state of course); the opening of the air compressor bypass valve 272 is gradually reduced to gradually reduce the compressed air bypass amount of the air compressor 25, as shown in fig. 8, which is a schematic diagram of the fuel cell air system before the cold start at low temperature is completed, and of course, other adjustment strategies may be set by the skilled person.

Step S370: the air compressor bypass valve 272 is closed.

It should be noted that if T3> t3_min is maintained for a period of time to indicate that the heating deicing is completed, the bypass process may be further delayed for a period of time to sufficiently heat deicing, as shown in fig. 8, and this step S370 may also be directly performed.

Step S380: turbine bypass valve 353 is closed, and turbine generator 35 is brought into a recovery power generation state.

Step S390: the FCU controls the fuel cell air system 10 to enter the normal power generation state after the cold start process is completed, wherein a schematic diagram of the fuel cell air system in the normal power generation state is shown in fig. 9, and a schematic diagram of the opening of the bypass valves corresponding to the first bypass circuit and the second bypass circuit in the control method of the present application is shown in fig. 10.

It should be noted that, in the control method of the present application, the turbine housing temperature sensor 358 for determining the cold start state is connected to the turbine generator inverter 34, and the sensor signal may be connected to the FCU, so as to meet the purpose of signal measurement; the turbine housing temperature sensor 358 is disposed in the turbine housing 38 near the working interface of the adjustable turbine nozzle 357 and/or the turbine wheel 359 to measure the turbine housing temperature T3 for condition determination at cold start in the control method of the present application, the turbine housing temperature sensor 358 may also be disposed at the turbine inlet flow passage 351 or other locations, and the purpose of measuring the turbine housing temperature T3 may be achieved by some corrective calculation.

Also, in addition to the temperature measured by the temperature sensor installed in the casing, the cold start control may be performed by using the ambient temperature T0 or the temperature T1c of the intake air measured by the air intake temperature sensor 23 as the temperature input for the judgment with a certain bypass time delay.

Regarding default opening degrees of the air compressor bypass valve 272 and the turbine bypass valve 353, the control method of the present application sets the air compressor bypass valve 272 to the fully closed state at the time of initialization, the failure state, the shutdown state; the turbine bypass valve 353 is set to the fully open state at the time of initialization, failure state, and shutdown state, and the technician may set the default opening of the two bypass valves to other states according to the characteristics of the different fuel cell power generation systems.

The adjustable turbine nozzle 357 is set to 100% open at initialization, fault condition, shutdown condition, cold start, and the technician can set the default opening of the nozzle to other conditions depending on the characteristics of the different fuel cell power generation systems.

During cold start, the air compressor 25 can be started to bypass high-temperature compressed air to the turbine bypass loop 36 through the air compressor bypass valve 272 to heat and deice the turbine rotating parts, at the moment, the fuel cell power generation system is not started to generate power, the high-voltage battery on the high-voltage direct-current bus is used for supplying power to the air compressor 25, and the air compressor enters a normal state after cold start is completed.

According to the control method of the fuel cell air system provided by the embodiment of the application, the air compressor provides compressed air required by power generation for the cathode of the electric pile to enable the fuel cell power generation system to directly enter a normal power generation state, and the integral air compressor in the prior art is not required to wait for successful ice breaking and cold starting of the turbine so as to normally generate power; meanwhile, the turbine bypass valve is opened to enable the waste heat and residual pressure waste gas in the cathode outlet of the fuel cell stack and the mixed gas of a part of air compressor outlet high-temperature compressed air from the air compressor bypass loop to be introduced into the turbine bypass flow channel to heat and deice the turbine rotating part, and then residual liquid water and/or ice slag are fully blown out to avoid secondary damage to the impeller, after the heat engine is finished, the air compressor bypass valve and the turbine bypass valve are closed according to a conventional state to switch the waste gas to the turbine impeller to perform expansion work power generation, so that energy recovery is achieved, the cold start time is greatly shortened, the operation economy of the fuel cell system is improved, and the start failure caused by clamping stagnation in the cold start of the turbine of the integrated air compressor can be effectively avoided.

It will be appreciated by those skilled in the art that, for convenience and brevity of description, only the above-described division of the functional modules is illustrated, and in practical application, the above-described functional allocation may be performed by different functional modules according to needs, i.e. the internal structure of the apparatus is divided into different functional modules to perform all or part of the functions described above.

In the embodiments provided in the present application, it should be understood that the disclosed apparatus and method may be implemented in other manners. For example, the apparatus embodiments described above are merely illustrative, e.g., the division of modules or units is merely a logical function division, and there may be additional divisions when actually implemented, e.g., multiple units or components may be combined or integrated into another apparatus, or some features may be omitted or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed with each other may be an indirect coupling or communication connection via some interfaces, devices or units, which may be in electrical, mechanical or other form.

The foregoing is merely illustrative of the present application, and the present application is not limited thereto, and any person skilled in the art will readily recognize that variations or substitutions are within the scope of the present application. Therefore, the protection scope of the application is subject to the protection scope of the claims.

Claims (10)

1. A fuel cell air system, the system comprising:

An air compressor and a turbine generator arranged in a distributed manner;

one end of the first bypass loop is connected with the air outlet of the air compressor, and the other end of the first bypass loop is connected with the turbine inlet of the turbine generator;

a second bypass circuit connected in parallel with a turbine runner of the turbine generator;

the control unit is used for controlling the first bypass loop to be opened when the fuel cell system is in a low-power generation working condition and discharging part of compressed air from the first bypass loop and the turbine runner; and when the fuel cell system is in a low-temperature cold start working condition, controlling the first bypass loop and/or the second bypass loop to be opened, and heating the rotating part of the turbine generator by using the compressed air and/or the exhaust gas of the fuel cell.

2. The system of claim 1, wherein the second bypass circuit is disposed within a housing of the turbine generator.

3. The system of claim 1, wherein the first bypass circuit comprises a first bypass valve, a first inlet flow passage, and a first outlet flow passage, wherein the first bypass valve is coupled to the first inlet flow passage and the first outlet flow passage, respectively, the first inlet flow passage is further coupled to an air outlet of the air compressor, and the first outlet flow passage is further coupled to the turbine inlet.

4. The system of claim 1, wherein the second bypass circuit includes a second bypass valve, a second inlet flow passage, and a second outlet flow passage, wherein the second bypass valve is coupled to the second inlet flow passage and the second outlet flow passage, respectively, the second inlet flow passage is further coupled to the turbine inlet, and the second outlet flow passage is further coupled to the turbine outlet of the turbine generator.

5. A fuel cell system comprising a fuel cell and the fuel cell air system according to any one of claims 1 to 4.

6. A vehicle comprising the fuel cell system according to claim 5.

7. A control method of a fuel cell air system according to any one of claims 1 to 4, wherein the method comprises:

identifying an actual condition of the fuel cell system;

if the fuel cell system is identified to be in a low-power generation working condition, a first bypass loop of the air system is controlled to be opened, and part of compressed air is discharged from the first bypass loop and a turbine runner of the air system;

And if the fuel cell system is identified to be in a low-temperature cold start working condition, controlling the first bypass loop and/or the second bypass loop of the air system to be opened, and heating the rotating part of the turbine generator by utilizing the compressed air and/or the exhaust gas of the fuel cell.

8. The method of claim 7, wherein the identifying the actual operating condition of the fuel cell system comprises:

if the fuel cell system is in an operating state, when the generated power of the fuel cell system is smaller than a preset power, controlling the fuel cell system to enter the low-power generation working condition;

and if the fuel cell system is in a closed state, controlling the fuel cell system to enter the low-temperature cold start working condition when the ambient temperature and the actual temperature of the turbine generator are both smaller than the corresponding preset temperature.

9. The method of claim 8, wherein said controlling the first bypass flow passage and/or the second bypass circuit of the air system to open comprises:

acquiring a target temperature at which a rotating component of the turbine generator can be unfrozen;

determining a target opening of the first bypass circuit and/or a second bypass circuit of the air system based on a difference between the actual temperature and the target temperature;

And controlling the first bypass loop and/or the second bypass loop to be opened to the target opening degree.

10. The method according to claim 9, characterized by further comprising, after controlling the first bypass circuit and/or the second bypass circuit to open to the target opening degree:

detecting a duration of opening of the first bypass circuit and/or the second bypass circuit;

if the duration is longer than the preset duration, reducing the current opening of the second bypass loop according to a preset step length so as to gradually increase the flow of the compressed air and/or the waste gas entering the turbine runner;

and when the end condition of the low-temperature cold start working condition is met, controlling the first bypass loop and the second bypass loop to be closed.