Efficient and energy-saving fuel cell air compressor cooling system

Abstract

The invention discloses an efficient and energy-saving fuel cell air compressor cooling system in the field of fuel cells, the system comprises a fuel cell stack, an air compressor, an intercooler, a humidifier, a turbine mechanism, a power generator, a storage battery and other components, exhaust air drives a turbine to rotate to generate power after passing through the humidifier, and electric energy is used for circulation of the cooling system; cooling liquid sequentially flows through the air compressor and the intercooler and is cooled through the radiator, and the radiating efficiency is enhanced through the axial flow fan. According to the system, compression energy of tail exhaust air is recovered through the turbine mechanism and the generator and stored in the storage battery through the power conversion device to supply power to the water pump and the axial flow fan, a cooling circulation loop independent of the fuel cell heat management system is formed, and external extra power consumption is avoided. Meanwhile, the humidifier is used for recycling heat energy and water vapor in tail exhaust air, the temperature and humidity of air entering the stack are adjusted, and the performance of the fuel cell is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and particularly to an efficient and energy-saving cooling system for a fuel cell air compressor. Background Art

[0002] With the increasing global demand for clean energy, fuel cells, as an efficient and low-pollution energy conversion device, have been widely used in fields such as automobiles and power generation. Among them, proton exchange membrane fuel cells have become the current mainstream technical direction due to their low operating temperature and high power density. In a fuel cell system, an air compressor is one of the core auxiliary components, and its function is to provide high-pressure air for the fuel cell stack to ensure the efficient progress of the electrochemical reaction. However, there are two key problems when the air compressor is working: one is that a large amount of heat is generated by the high-speed rotating motor rotor and compressed air. If not cooled in time, it may cause demagnetization of the motor or too high an air temperature entering the fuel cell stack, affecting the performance of the fuel cell stack; the other is that the air compressor itself has high energy consumption, especially during high-power operation, and its power consumption accounts for more than 30% of the total power consumption of the fuel cell system. How to reduce energy consumption and recycle energy has become the key to improving system efficiency.

[0003] Traditional solutions usually adopt independent water-cooling or air-cooling systems to cool the air compressor and compressed air. For example, an intercooler is used to cool the high-temperature compressed air, or an additional water pump and radiator are used to cool the motor rotor. These devices require external energy supply, such as driving water pumps, fans, etc., resulting in an increase in the overall power consumption of the system. For example, although Patent CN113270614B cools the compressed air through an intercooler, it does not consider the cooling of the motor of the air compressor itself, and the axial flow fan supporting the radiator requires additional power consumption; Patent CN116123064B cools the air compressor by introducing the air after the intercooler through a bypass valve, but the intercooler still relies on external coolant circulation, increasing the complexity and power consumption of the system. Secondly, the high-pressure air discharged from the air compressor carries a large amount of unused energy (such as pressure energy and thermal energy), and the existing technology often directly discharges it into the atmosphere, resulting in energy waste. Summary of the Invention

[0004] The present invention aims to provide an efficient and energy-saving cooling system for a fuel cell air compressor to solve the problems of high power consumption in the existing fuel cell air compressor cooling using external cooling devices and the failure to recycle the compressed energy of the discharged air.

[0005] To solve the above technical problems, the present invention provides the following technical solution: An efficient and energy-saving cooling system for a fuel cell air compressor, comprising a fuel cell stack, an air flow meter, an air compressor, an intercooler, a humidifier, a first throttle valve, a second throttle valve, a turbine mechanism, a generator, a power conversion device, a storage battery, a water pump, a radiator, and an axial flow fan;

[0006] One end of the air flow meter is in communication with external air, and the other end is connected to the air inlet of the air compressor;

[0007] The air outlet of the air compressor is connected to the air side inlet of the intercooler. The air side outlet of the intercooler is connected to the air inlet end of the humidifier. The air outlet end of the humidifier is connected to the cathode inlet of the fuel cell stack through the first throttle valve;

[0008] The cathode outlet of the fuel cell stack is connected to the tail gas inlet of the humidifier through the second throttle valve. The tail gas outlet of the humidifier is connected to the air inlet of the turbine mechanism. The air outlet of the turbine mechanism is in communication with external air;

[0009] The power output shaft of the turbine mechanism is connected to the rotor shaft of the generator. The output end of the generator is electrically connected to the input end of the storage battery through the power conversion device. The output end of the storage battery is respectively electrically connected to the power supply ends of the water pump and the axial flow fan;

[0010] The water outlet of the water pump is connected to the cooling water channel inlet of the air compressor. The cooling water channel outlet of the air compressor is connected to the inlet of the intercooler. The liquid side outlet of the intercooler is connected to the inlet of the radiator. The outlet of the radiator is connected to the water inlet of the water pump. The axial flow fan is arranged on the heat dissipation side of the radiator; the water pump, the air compressor, the intercooler, the radiator and the axial flow fan form a cooling circulation loop.

[0011] The working principle of the present invention: External air is metered by the air flow meter and then pressurized by the air compressor. The high-temperature compressed air is first cooled by the intercooler, and then undergoes heat and moisture exchange with the tail gas discharged from the fuel cell stack through the humidifier to improve the temperature and humidity of the air entering the stack and improve the reaction conditions of the fuel cell stack. The pressure energy carried by the tail gas drives the turbine mechanism to rotate, driving the generator to generate electricity. The electric energy is stored in the storage battery through the power conversion device, providing an independent power source for the cooling system and avoiding relying on external additional power consumption; the storage battery supplies power to the water pump and the axial flow fan, driving the coolant to flow through the cooling water channel of the air compressor and the intercooler in sequence to cool the motor rotor of the air compressor and the compressed air. The heated coolant is dissipated by the axial flow fan in the radiator and then recycled; the fuel cell controller adjusts the rotation speed of the air compressor according to the set value and feedback value of the air flow, and continuously adjusts the opening of the second throttle valve according to the set value and feedback value of the air pressure. The independent control of the air flow and pressure is achieved through the air compressor and the adjustment of the opening of the second throttle valve. When the machine is shut down, the first and second throttle valves are closed to isolate the cathode chamber of the fuel cell stack from the external air.

[0012] Furthermore, both the first throttle valve and the second throttle valve are butterfly valves with adjustable opening degrees, and a pressure sensor is connected to the pipeline between the first throttle valve and the cathode inlet of the fuel cell stack. By adopting butterfly valves with adjustable opening degrees and pressure sensors, precise and independent control of the air flow rate and pressure entering the stack is achieved, ensuring the stable operation of the fuel cell stack under different working conditions and effectively improving the reaction efficiency and adaptability of the stack.

[0013] Furthermore, the turbine mechanism includes a turbine housing, turbine blades, and a transmission shaft. The turbine blades are coaxially connected to the rotor shaft of the generator through the transmission shaft. The intake end of the turbine housing is connected to the exhaust gas outlet of the humidifier, and the outlet end of the turbine housing is in communication with the external atmosphere. Through the coaxial transmission design of the turbine mechanism, it can ensure the efficient conversion of pressure energy into electrical energy, with a compact structure and low transmission loss, guaranteeing the reliable recovery of the energy of the exhaust air and providing continuous and stable power support for the cooling system.

[0014] Furthermore, the power conversion device includes a rectifier and a voltage regulator. The input end of the rectifier is electrically connected to the output end of the generator, and the output end of the rectifier is electrically connected to the input end of the battery through the voltage regulator. By setting up the power conversion device, the rectification and voltage stabilization of the electrical energy output by the generator can be carried out, improving the charging efficiency and safety of the battery and ensuring the stable power supply of the cooling system.

[0015] Furthermore, the coolant in the cooling circulation loop is an ethylene glycol aqueous solution or deionized water. By setting up the cooling circulation loop, the power consumption superposition caused by sharing resources with the stack cooling system is avoided, enhancing the heat dissipation reliability and energy-saving effect of the system.

[0016] Furthermore, when the fuel cell stack is shut down, both the first throttle valve and the second throttle valve are in a fully closed state, isolating the cathode chamber of the fuel cell stack from the external air. By setting the first throttle valve and the second throttle valve when the fuel cell stack is shut down, it can effectively prevent pollutants such as dust and moisture from entering the stack, reduce electrode corrosion and performance degradation, and extend the service life of the fuel cell stack.

[0017] The beneficial effects of the present invention:

[0018] 1. Different from the prior art which relies on external coolant circulation or the power consumption of additional fans and water pumps, the present invention utilizes the pressure energy of the exhaust air to drive a turbine mechanism for power generation. After power conversion, the battery supplies power to the cooling system (water pump, axial flow fan), forming a closed cooling circulation loop independent of the fuel cell thermal management system. The coolant cools the motor rotor of the air compressor and the compressed air in the intercooler in sequence, and after heating up, dissipates heat through the radiator. The whole process does not require external energy input, reducing the power consumption of the auxiliary system at the source. For example, when operating at high power, the energy recovery efficiency of the exhaust air increases, and the battery can provide more electrical energy to drive the cooling system to operate efficiently, avoiding the contradiction of "high cooling demand accompanied by high additional power consumption" in the traditional solution and improving the energy utilization rate of the system;

[0019] 2. The cooling circulation loop is designed according to the heat generation characteristics of the air compressor. The coolant directly flows through the cooling channels of the air compressor motor, quickly reducing the rotor temperature and preventing the demagnetization of the magnetic steel. At the same time, it cools the compressed air in the intercooler to avoid the influence of high-temperature air on the performance of the fuel cell stack. This loop works in coordination with the humidifier, using the thermal energy and water vapor of the exhaust air from the fuel cell stack to adjust the temperature and humidity of the incoming air, reducing the risk of "waterlogging" or "membrane drying" of the fuel cell stack. In addition, the system can dynamically match the energy recovery and cooling power consumption according to the power of the fuel cell: at low power, low-energy cooling meets the basic requirements, and at high power, high-energy recovery drives strong heat dissipation, achieving "energy supply on demand" and significantly improving the operating stability of the air compressor and the fuel cell stack;

[0020] 3. In addition to the cooling circulation, the present invention converts the pressure energy of the exhaust air from the fuel cell stack into electrical energy through a turbine mechanism, and combines the recovery and utilization of the exhaust heat energy and water vapor by the humidifier to form a multi-stage energy utilization system of "pressure energy - electrical energy - thermal energy". Compared with the prior art which directly discharges the exhaust energy or only performs single-stage cooling (such as simply cooling down by an intercooler), the present invention realizes the deep recovery of the discharged energy, not only reducing the power consumption of the cooling system, but also improving the reaction conditions of the fuel cell stack through the humidifier, thus enhancing the overall efficiency of the fuel cell system;

[0021] 4. The cooling circulation loop and the cathode gas path of the fuel cell stack are completely isolated by controlling the first throttle valve and the second throttle valve. When the machine stops, the first throttle valve and the second throttle valve are fully closed to prevent external pollutants from entering the cathode chamber of the fuel cell stack, reducing electrode corrosion and performance degradation. The independent selection of the coolant can adapt to different working conditions, avoiding the problems of medium pollution or scaling that may be caused by the traditional shared cooling system, and further enhancing the system reliability and the service life of the fuel cell stack. Brief Description of the Drawings

[0022] Figure 1 It is a schematic structural diagram of an efficient and energy-saving fuel cell air compressor cooling system of the present invention. Detailed Embodiment

[0023] The following is a further detailed description through specific embodiments:

[0024] The reference numerals in the accompanying drawings of the specification include: fuel cell stack 1, air flow meter 2, air compressor 3, intercooler 4, humidifier 5, first throttle valve 6, pressure sensor 7, second throttle valve 8, turbine mechanism 9, generator 10, power conversion device 11, battery 12, water pump 13, radiator 14, and axial flow fan 15.

[0025] The embodiment is basically as shown in the attached Figure 1 : An efficient and energy-saving cooling system for a fuel cell air compressor, comprising a fuel cell stack 1, an air flow meter 2, an air compressor 3, an intercooler 4, a humidifier 5, a first throttle valve 6, a pressure sensor 7, a second throttle valve 8, a turbine mechanism 9, a generator 10, a power conversion device 11, a battery 12, a water pump 13, a radiator 14, and an axial flow fan 15;

[0026] One end of the air flow meter 2 is in communication with external air, and the other end is fixedly connected to the air inlet of the air compressor 3. The air outlet of the air compressor 3 is fixedly connected to the air side inlet of the intercooler 4. The air side outlet of the intercooler 4 is fixedly connected to the air inlet end of the humidifier 5. The air outlet end of the humidifier 5 is fixedly connected to the cathode inlet of the fuel cell stack 1 through the first throttle valve 6. A pressure sensor 7 is fixedly connected to the pipeline between the first throttle valve 6 and the cathode inlet of the fuel cell stack 1. Both the first throttle valve 6 and the second throttle valve 8 are butterfly valves with adjustable openings. The cathode outlet of the fuel cell stack 1 is fixedly connected to the tail gas inlet of the humidifier 5 through the second throttle valve 8;

[0027] The turbine mechanism 9 includes a turbine housing, turbine blades, and a transmission shaft. The turbine blades are coaxially and fixedly connected to the rotor shaft of the generator 10 through the transmission shaft. The air inlet end of the turbine housing is fixedly connected to the tail gas outlet of the humidifier 5. The air outlet end of the turbine housing is in communication with the external atmosphere. The tail gas outlet of the humidifier 5 is connected to the air inlet of the turbine mechanism 9, and the air outlet of the turbine mechanism 9 is in communication with external air;

[0028] The power conversion device 11 includes a rectifier and a voltage regulator. The input end of the rectifier is electrically connected to the output end of the generator 10. The output end of the rectifier is electrically connected to the input end of the battery 12 through the voltage regulator. The output end of the battery 12 is electrically connected to the power supply ends of the water pump 13 and the axial flow fan 15 respectively. The water outlet of the water pump 13 is fixedly connected to the cooling water channel inlet of the air compressor 3. The cooling water channel outlet of the air compressor 3 is fixedly connected to the inlet of the intercooler 4. The liquid side outlet of the intercooler 4 is fixedly connected to the inlet of the radiator 14. The outlet of the radiator 14 is fixedly connected to the water inlet of the water pump 13. The axial flow fan 15 is arranged on the heat dissipation side of the radiator 14;

[0029] The water pump 13, air compressor 3, intercooler 4, radiator 14 and axial flow fan 15 form a cooling circulation loop, and the coolant in the cooling circulation loop is ethylene glycol aqueous solution or deionized water.

[0030] The specific implementation process is as follows: When the fuel cell is in the shutdown state, the first throttle valve 6 and the second throttle valve 8 are both in the closed state. At this time, the cathode chamber of the fuel cell stack 1 is isolated from the air, and pollutants in the surrounding environment cannot enter the fuel cell stack 1 through the air pipeline to cause pollution.

[0031] When the fuel cell is in the working state, the first throttle valve 6 is fully open to allow air to pass through. The fuel cell controller adjusts the speed of the air compressor 3 according to the set value and feedback value of the air flow. At this time, the external air first passes through the air flow meter 2 to measure the real-time flow, and then enters the air compressor 3 for pressurization to form high-temperature and high-pressure air that meets the reaction requirements of the stack. The compressed air undergoes gas-liquid heat exchange in the intercooler 4, and the heat is taken away by the coolant to reduce the temperature, avoiding the influence of high temperature on the performance of the stack. The cooled air enters the humidifier 5 and undergoes heat and humidity exchange with the tail exhaust air discharged from the cathode of the fuel cell stack 1 through the diaphragm. The waste heat and water vapor in the tail exhaust air are fully utilized to increase the humidity of the air entering the stack and adjust the temperature to be close to the operating temperature of the stack, improving the conduction performance of the proton exchange membrane. The tail exhaust air still has relatively high compression energy after passing through the humidifier 5. The compressed air enters the turbine mechanism 9, and the high-pressure air flow drives the turbine blades to rotate, driving the generator 10 to generate electricity through the transmission shaft, converting the pressure energy of the air into alternating current, which is then rectified and regulated by the power conversion device 11 and stored in the battery 12. The battery 12 supplies power to the water pump 13 and the axial flow fan 15. The coolant flows out after being pressurized by the water pump 13, passes through the air compressor 3 and the intercooler 4 in sequence, cools the motor rotor and the outlet air in the air compressor 3, and the temperature of the coolant increases after heat exchange in the intercooler 4 and then flows into the radiator 14. The axial flow fan 15 blows cooling air into the radiator 14 to cool the internal coolant, and finally the coolant flows back to the water pump 13;

[0032] In terms of pressure control, the controller of the fuel cell stack 1 dynamically adjusts the opening of the second throttle valve 8 according to the real-time operation requirements of the stack and the cathode inlet air pressure data fed back by the pressure sensor 7, precisely controlling the air pressure entering the stack to ensure that the stack can efficiently react under different loads. The system also has an adaptive adjustment ability: when the stack consumes less power during operation, the tail exhaust air pressure is relatively low, and the turbine power generation energy only needs to meet the basic cooling requirements; when the stack consumes more power during operation, the tail exhaust air pressure increases, the turbine recovery energy increases, and the battery 12 stores electricity and then provides electrical energy to drive the cooling system to improve the heat dissipation ability, realizing the dynamic balance of "energy recovery - cooling demand".

[0033] The above are only embodiments of the present invention, and common knowledge such as specific structures and characteristics known in the art are not described in detail herein. It should be noted that for those skilled in the art, without departing from the structure of the present invention, several modifications and improvements can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the implementation effect of the present invention and the practicability of the patent. The protection scope claimed in this application shall be subject to the content of its claims, and the specific implementation manners described in the specification can be used to interpret the content of the claims.

Claims

1. An efficient and energy-saving cooling system for a fuel cell air compressor, characterized in that: It includes a fuel cell stack, an air flow meter, an air compressor, an intercooler, a humidifier, a first throttle valve, a second throttle valve, a turbine mechanism, a generator, a power conversion device, a storage battery, a water pump, a radiator and an axial flow fan; One end of the air flow meter is communicated with external air, and the other end is connected to the air inlet of the air compressor; The air outlet of the air compressor is connected to the air side inlet of the intercooler, the air side outlet of the intercooler is connected to the air inlet end of the humidifier, and the air outlet end of the humidifier is connected to the cathode inlet of the fuel cell stack through the first throttle valve; The cathode outlet of the fuel cell stack is connected to the tail gas inlet of the humidifier through the second throttle valve, the tail gas outlet of the humidifier is connected to the air inlet of the turbine mechanism, and the air outlet of the turbine mechanism is communicated with external air; The power output shaft of the turbine mechanism is connected to the rotor shaft of the generator, the output end of the generator is electrically connected to the input end of the storage battery through the power conversion device, and the output end of the storage battery is respectively electrically connected to the power supply ends of the water pump and the axial flow fan; The water outlet of the water pump is connected to the cooling water channel inlet of the air compressor, the cooling water channel outlet of the air compressor is connected to the inlet of the intercooler, the liquid side outlet of the intercooler is connected to the inlet of the radiator, the outlet of the radiator is connected to the water inlet of the water pump, and the axial flow fan is arranged on the heat dissipation side of the radiator; the water pump, the air compressor, the intercooler, the radiator and the axial flow fan form a cooling circulation loop.

2. The high-efficiency and energy-saving fuel cell air compressor cooling system according to claim 1, characterized in that: Both the first throttle valve and the second throttle valve are butterfly valves with adjustable opening degrees, and a pressure sensor is connected to the pipeline between the first throttle valve and the cathode inlet of the fuel cell stack.

3. The high-efficiency and energy-saving fuel cell air compressor cooling system according to claim 2, characterized in that: The turbine mechanism includes a turbine housing, turbine blades and a transmission shaft. The turbine blades are coaxially connected to the rotor shaft of the generator through the transmission shaft. The air inlet end of the turbine housing is connected to the tail gas outlet of the humidifier, and the air outlet end of the turbine housing is communicated with the external atmosphere.

4. An efficient and energy-saving cooling system for a fuel cell air compressor according to claim 3, characterized in that: The power conversion device includes a rectifier and a voltage regulator. The input end of the rectifier is electrically connected to the output end of the generator, and the output end of the rectifier is electrically connected to the input end of the storage battery through the voltage regulator.

5. An efficient and energy-saving fuel cell air compressor cooling system according to claim 4, characterized in that: The coolant of the cooling circulation loop is ethylene glycol aqueous solution or deionized water.

6. The high-efficiency and energy-saving fuel cell air compressor cooling system according to claim 5, wherein: When the fuel cell stack shuts down, both the first throttle valve and the second throttle valve are in a fully closed state, and the cathode chamber of the fuel cell stack is isolated from external air.

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