Fuel cell integrated with heat pump energy recovery system, and energy recovery control method

Abstract

Disclosed in the present invention are a fuel cell integrated with a heat pump energy recovery system, and an energy recovery control method. The main features are that: a heat pump system is arranged between a cooling system and an air supply system, and after absorbing waste heat in the cooling system, the heat pump system heats exhaust tail gas discharged by a cell stack module, so as to increase the temperature of exhaust tail gas entering an expander, thereby improving the energy recovery efficiency of the expander. The heat pump system has a simple structure, and an energy recovery strategy is reasonable, thereby greatly simplifying the structure of the energy recovery system of the fuel cell, reducing manufacturing costs, and eliminating the risk of temperature runaway.

Description

Fuel cell integrated with heat pump energy recovery system and energy recovery control method Technical field:

[0001] The invention relates to a fuel cell integrated with a heat pump energy recovery system and an energy recovery control method. Background technology:

[0002] A fuel cell is an energy conversion device that generates electricity through the electrochemical reaction of hydrogen and oxygen. It boasts high energy conversion efficiency, a simple structure, low noise, and zero pollution. Fuel cells typically operate at relatively high pressures. The air entering the fuel cell stack must be compressed to a certain pressure, where the oxygen reacts electrochemically with the hydrogen at the anode, generating electricity, water, and heat. The exhaust air remains at a relatively high pressure, and this higher-pressure and higher-temperature gas carries a high level of energy.

[0003] Currently, fuel cells generally discharge the finished reaction gases directly through the exhaust without any treatment. Some systems also utilize an air compressor with a turboexpander, which recovers energy from the exhaust gas, reducing compressor power consumption and thereby improving fuel cell system efficiency. Because the exhaust gas from a fuel cell reaction contains large amounts of liquid water and water vapor, separation of the liquid water entering the expander is generally required to prevent corrosion of the expander. The path from the fuel cell exhaust to the expander inlet typically includes humidifiers, backpressure valves, water separators, and piping, which can lower the exhaust gas temperature. Furthermore, lower gas temperature reduces the saturation concentration of water vapor, increasing the amount of liquid water present, and increasing the requirements for the water separator, which can further increase pressure drop. Therefore, the higher the gas temperature entering the expander, the higher the system's energy recovery efficiency. Therefore, it is important to maximize the gas temperature entering the expander.

[0004] Currently, there are two technical solutions on the market to increase the exhaust gas temperature entering the expander:

[0005] Option 1: An air-to-air heat exchanger is installed between the air compressor and the intercooler, and the high-temperature gas at the air compressor outlet is used to exchange heat with the exhaust gas, so that the temperature of the gas entering the expander is increased. The specific structure is shown in Figure 1. Although the temperature of the air compressor outlet is high in Option 1, the energy is limited and the heat conversion efficiency is not high. The effect of increasing the temperature of the gas entering the expander is limited, and thus the impact on improving the energy recovery efficiency of the fuel cell system is limited.

[0006] Option 2: Install an air-to-liquid heat exchanger, heat storage pump, and heat storage tank between the air compressor and the intercooler, and another air-to-liquid heat exchanger, heat storage pump, and heat storage tank between the water distributor and the expander inlet. The heat storage tank is used to control the flow of the heat exchange medium to control the temperature of the gas entering the fuel cell stack. This also aims to transfer the high-temperature gas energy at the air compressor outlet to the expander inlet, thereby increasing the temperature of the gas entering the expander without affecting the normal operation of the fuel cell stack. Option 2 requires the installation of an air-to-liquid heat exchanger, heat storage pump, and heat storage tank, but there are still problems or defects: the installation of two heat storage pumps and heat storage tanks complicates the system structure and poses the risk of uncontrolled gas temperature at the fuel cell stack inlet.

[0007] Summary of the invention:

[0008] The purpose of the present invention is to provide a fuel cell and energy recovery control method integrated with a heat pump energy recovery system to solve the technical problems that the current fuel cell exhaust gas energy recovery is either inefficient or the recovery strategy is unreasonable, resulting in a complex structure and the risk of temperature runaway.

[0009] The purpose of the present invention is achieved through the following technical solutions.

[0010] A fuel cell with an integrated heat pump energy recovery system includes a fuel cell stack module, a hydrogen supply and recovery system, an air supply system and a cooling system. The hydrogen supply and recovery system is connected to the hydrogen inlet and hydrogen outlet of the fuel cell stack module, the air supply system is connected to the air inlet and air outlet of the fuel cell stack module, and the cooling system is connected to the coolant inlet and coolant outlet of the fuel cell stack module. The air supply system includes an air compressor, and the external air is compressed and heated by the air compressor and then sent to the air inlet of the fuel cell stack module. The air compressor is an air compressor with an expander, and the tail gas discharged from the air outlet of the fuel cell stack module enters the expander, and the expander is used to recover energy from the tail gas. It is characterized in that a heat pump system is arranged between the cooling system and the air supply system, and the heat pump system absorbs waste heat in the cooling system and heats the tail gas discharged from the fuel cell stack module to increase the temperature of the tail gas entering the expander, thereby improving the energy recovery efficiency of the expander.

[0011] The air compressor with an expander comprises a motor, an air compressor head and an expander, wherein the air compressor head and the expander are respectively mounted at both ends of a rotating shaft of the motor.

[0012] The above-mentioned heat pump system includes a condenser, a heat pump compressor, a throttling device, an evaporator and a heat medium. The condenser, the heat pump compressor, the throttling device and the evaporator are connected by pipes to form a circulation path, and the heat medium flows in the circulation path.

[0013] The above-mentioned air supply system also includes an air filter, a flow meter, an intercooler, a humidifier, a back pressure valve and a water separator. The external air is sent to the air inlet of the fuel cell module through the air filter, flow meter, air compressor, intercooler and humidifier. The intercooler is connected to the cooling system and obtains coolant from the cooling system; the cooling system includes a thermostatic valve, a radiator, a heater and a water pump. The coolant absorbs the heat generated by the operation of the fuel cell module and flows out from the coolant outlet through the thermostatic valve and is divided into two paths. One path of coolant passes through the radiator to the water pump, and the other path of coolant passes through the heater to the water pump. The coolant output from the water pump enters the coolant inlet of the fuel cell module to form a circulation.

[0014] The above-mentioned condenser is provided before the inlet of the expander.

[0015] The above-mentioned condenser is arranged between the back pressure valve and the water separator.

[0016] In the above-mentioned embodiment, an evaporator is arranged between the thermostatic valve and the radiator. The coolant of the cooling system flows through the evaporator and exchanges heat with the heat medium inside the evaporator. The heat medium coming out of the evaporator enters the condenser after passing through the heat pump compressor. The tail exhaust discharged from the fuel cell module enters the condenser through the back pressure valve and the water separator. The tail exhaust flowing through the condenser exchanges heat with the heat medium flowing through the condenser, so that the temperature of the tail exhaust flowing through the condenser increases, and the temperature of the tail exhaust entering the expander is increased, thereby improving the energy recovery efficiency of the expander.

[0017] The coolant inlet of the above-mentioned stack module is provided with a temperature sensor.

[0018] The rotation speed of the heat pump compressor is adjustable.

[0019] An energy recovery control method for a fuel cell integrated with a heat pump energy recovery system, wherein the fuel cell further comprises a fuel cell system controller, which controls the operation of a stack module, a thermostatic valve, a radiator, a heater, a water pump, and a heat pump compressor, and wherein a temperature sensor transmits a coolant temperature signal at a coolant inlet to the fuel cell system controller; the energy recovery control method is characterized in that:

[0020] When the temperature sensor detects that the coolant temperature T at the coolant inlet is lower than the lower limit set temperature T1, the fuel cell system controller controls the thermostatic valve to allow the coolant from the coolant outlet of the stack module to pass through the thermostatic valve, heater and water pump and then return to the coolant inlet of the stack module, forming a small cooling circuit.

[0021] When the temperature sensor detects that the coolant temperature T at the coolant inlet is greater than or equal to the lower limit set temperature T1, the fuel cell system controller controls the thermostatic valve to allow the coolant from the coolant outlet of the stack module to pass through the thermostatic valve, evaporator, radiator and water pump and then return to the coolant inlet of the stack module, forming a large cooling circuit cycle;

[0022] The thermostatic valve is used to select one of the two working modes: large cooling circuit and small cooling circuit.

[0023] The specific steps of the above energy recovery control method are:

[0024] Step 1: Determine whether to enter the cooling circuit large cycle working mode. If so, proceed to step 2; if not, proceed to step 8;

[0025] Step 2: The heat pump system starts, the heat pump compressor starts working, and the heat pump compressor speed N increases or decreases as the coolant inlet temperature T increases or decreases;

[0026] Step 3: Determine whether the coolant temperature T at the coolant inlet is greater than the upper limit set temperature T2. If so, proceed to step 4; if not, return to step 2.

[0027] Step 4: The radiator's built-in fan starts, and the fan speed n is adjusted to increase or decrease as the temperature T increases or decreases;

[0028] Step 5: Determine whether the coolant temperature T at the coolant inlet is less than or equal to the lower limit set temperature T1. If not, return to step 4. If so, proceed to step 6.

[0029] Step 6: The radiator's built-in fan stops working;

[0030] Step 7: Determine again whether the coolant temperature T at the coolant inlet is less than or equal to the lower limit set temperature T1. If not, return to step 2. If so, proceed to step 8.

[0031] Step 8: The heat pump system is shut down, the heat pump compressor stops working, and the cooling circuit small cycle working mode is re-entered.

[0032] The lower limit setting temperature T1 and the upper limit setting temperature T2 mentioned above are between 50 and 80 degrees Celsius.

[0033] Compared with the prior art, the present invention has the following effects:

[0034] 1. The present invention incorporates a heat pump system between the cooling system and the air supply system. This system absorbs waste heat from the cooling system and heats the exhaust gas from the fuel cell stack module, raising the exhaust gas temperature before entering the expander, thereby improving the expander's energy recovery efficiency. This heat pump system can effectively improve the energy recovery efficiency of fuel cell exhaust gas, avoiding the technical problem of low energy recovery efficiency caused by using high-temperature air from the air compressor outlet to heat-exchange the exhaust gas and raise its temperature.

[0035] 2. The heat pump system has a simple structure, mature technology, and a reasonable energy recovery strategy. It can greatly simplify the energy recovery system structure of the fuel cell, reduce manufacturing costs, and eliminate the risk of temperature runaway.

[0036] 3. Other advantages of the present invention are described in detail in the embodiment section. Description of the drawings:

[0037] FIG1 is a block diagram of a fuel cell energy recovery system in the prior art;

[0038] FIG2 is a structural diagram of a fuel cell according to a first embodiment of the present invention;

[0039] FIG3 is a block diagram of the specific structure of a fuel cell according to Example 1 of the present invention;

[0040] FIG4 is a control flow chart of fuel cell tail exhaust energy recovery according to the second embodiment of the present invention. Specific implementation method:

[0041] The present invention will be further described in detail below through specific embodiments in conjunction with the accompanying drawings.

[0042] Embodiment one:

[0043] As shown in Figures 2 and 3, this embodiment provides a fuel cell with an integrated heat pump energy recovery system, including a fuel cell stack module, a hydrogen supply and hydrogen recovery system, an air supply system and a cooling system. The hydrogen supply and hydrogen recovery system is connected to the hydrogen inlet and hydrogen outlet of the fuel cell stack module, the air supply system is connected to the air inlet and air outlet of the fuel cell stack module, and the cooling system is connected to the coolant inlet and coolant outlet of the fuel cell stack module. The air supply system includes an air compressor, and the external air is compressed and heated by the air compressor and then sent to the air inlet of the fuel cell stack module. The air compressor is an air compressor with an expander 6. The tail gas discharged from the air outlet of the fuel cell stack module enters the expander 6, and the expander 6 is used to recover the energy of the tail gas. It is characterized in that a heat pump system is arranged between the cooling system and the air supply system, and the heat pump system absorbs the waste heat in the cooling system and heats the tail gas discharged from the fuel cell stack module to increase the temperature of the tail gas entering the expander, thereby improving the energy recovery efficiency of the expander.

[0044] The present invention is provided with a heat pump system between the cooling system and the air supply system. The heat pump system absorbs the waste heat in the cooling system and then heats the exhaust gas discharged from the fuel cell module to increase the temperature of the exhaust gas entering the expander, thereby improving the energy recovery efficiency of the expander. A heat pump is a highly efficient and energy-saving device that makes full use of low-grade thermal energy. The working principle of a heat pump is a mechanical device that forces heat from a low-temperature object to a high-temperature object in a reverse cycle. It consumes only a small amount of reverse cycle net work to obtain a large amount of heat supply, and can effectively utilize low-grade thermal energy that is difficult to apply to achieve energy-saving purposes. The heat pump system has a simple structure, mature technology, and a reasonable energy recovery strategy. It can greatly simplify the energy recovery system structure of the fuel cell, reduce manufacturing costs, and eliminate the risk of temperature runaway.

[0045] The air compressor with the expander 6 comprises a motor, an air compressor head and the expander 6 , and the air compressor head and the expander 6 are respectively mounted on both ends of the rotating shaft of the motor.

[0046] The above-mentioned heat pump system includes a condenser 1, a heat pump compressor 2, a throttling device 3, an evaporator 4 and a heat medium. A pipeline is used to connect the condenser 1, the heat pump compressor 2, the throttling device 3 and the evaporator 4 to form a circulation path, and the heat medium flows in the circulation path.

[0047] The above-mentioned air supply system also includes an air filter (abbreviated as air filter), a flow meter, an intercooler 9, a humidifier, a back pressure valve 8 and a water separator 7. The external air is sent to the air inlet of the fuel cell module through the air filter, flow meter, air compressor, intercooler 9 and humidifier. The intercooler 9 is connected to the cooling system and obtains coolant from the cooling system; the cooling system includes a thermostatic valve 11, a radiator 5, a heater and a water pump. The coolant absorbs the heat generated by the operation of the fuel cell module and flows out from the coolant outlet through the thermostatic valve 11 and is divided into two paths. One path of coolant passes through the radiator 5 to reach the water pump, and the other path of coolant passes through the heater to reach the water pump. The coolant output from the water pump enters the coolant inlet of the fuel cell module to form a cycle.

[0048] The condenser 1 is provided before the inlet of the expander 6 .

[0049] The above-mentioned condenser 1 is arranged between the back pressure valve 8 and the water separator 7 .

[0050] In the above-mentioned embodiment, an evaporator 4 is arranged between the thermostatic valve 11 and the radiator 5. The coolant of the cooling system flows through the evaporator 4 and exchanges heat with the heat medium inside the evaporator 4. The heat medium coming out of the evaporator 4 enters the condenser 1 after passing through the heat pump compressor 2. The tail exhaust discharged from the fuel cell module enters the condenser 1 through the back pressure valve and the water separator. The tail exhaust flowing through the condenser 1 exchanges heat with the heat medium flowing through the condenser 1, so that the temperature of the tail exhaust flowing through the condenser 1 increases, and the temperature of the tail exhaust entering the expander is increased, thereby improving the energy recovery efficiency of the expander.

[0051] A temperature sensor 10 is provided at the coolant inlet of the stack module.

[0052] The rotation speed of the heat pump compressor 2 is adjustable.

[0053] The present invention operates as follows: The present invention provides a fuel cell with an integrated heat pump energy recovery system. The exhaust gas from the fuel cell reaction is passed through an expander to perform work. The heat pump collects some of the waste heat from the fuel cell's cooling system and uses it to raise the temperature of the exhaust gas entering the expander inlet. The heat pump system comprises at least a condenser 1, a heat pump compressor 2, a throttling device 3, an evaporator 4, and a heat medium. The evaporator 4 is located in front of the inlet of the fuel cell system's radiator 5. The operating temperature of the fuel cell stack module is generally between 60°C and 80°C. The high-temperature liquid at the stack's coolant outlet is reduced through heat exchange in the radiator 5. This energy, which is typically equivalent to the electrical energy generated by the stack module, must be exhausted from the radiator 5 to the atmosphere. The evaporator 4 of the heat pump system is located in front of the radiator 5. At this point, the heat medium in the heat pump system is in a low-temperature, low-pressure liquid state. The evaporator 4 absorbs a large amount of heat from the fuel cell's cooling system. This process, a liquid-to-liquid exchange, is highly efficient. This process vaporizes the heat medium, turning it into a low-temperature, low-pressure gas. The low-temperature, low-pressure gas heat medium flows to the heat pump compressor 2. The heat pump compressor 2 rotates and generates work, compressing the low-temperature, low-pressure gas heat medium into high-temperature, high-pressure gas with minimal energy. This high-temperature gas can reach approximately 150°C thanks to the heat pump system's configuration. The condenser 1 is located in the fuel cell's exhaust pipeline, between the water separator 7 and the expander 6. The high-temperature, high-pressure gas heat medium flows into the condenser 1, exchanging heat with the fuel cell's exhaust gas. This process raises the exhaust gas temperature, which ranges from 60°C to 80°C, to above 100°C, reducing the amount of liquid water left over from incomplete water separation and lowering the water separation efficiency requirements of the water separator 7 in the fuel cell system. It also reduces the impact of water in the exhaust gas on the expander 6, improving its durability and reliability. The high-temperature gas further enhances its recovery efficiency. After exchanging heat with the exhaust gas through the condenser 1, the high-temperature, high-pressure gas heat medium becomes a low-temperature, high-pressure liquid. This heat medium is then throttled by the throttling device 3 in the heat pump system, returning it to a low-temperature, low-pressure liquid. Then enter the evaporator 4 and repeat the process.

[0054] Example 2:

[0055] As shown in FIG4 , an energy recovery control method for a fuel cell using the integrated heat pump energy recovery system of Example 1 is provided. The fuel cell further includes a fuel cell system controller, which controls the operation of the stack module, the thermostatic valve 11, the radiator 5, the heater, the water pump, and the heat pump compressor 2. The temperature sensor 10 transmits a coolant temperature signal at the coolant inlet to the fuel cell system controller. The energy recovery control method is characterized in that:

[0056] When the temperature sensor 10 detects that the coolant temperature T at the coolant inlet is lower than the lower limit set temperature T1, the fuel cell system controller controls the thermostatic valve 11 so that the coolant from the coolant outlet of the stack module passes through the thermostatic valve 11, the heater and the water pump and returns to the coolant inlet of the stack module, forming a small cooling circuit.

[0057] When the temperature sensor 10 detects that the coolant temperature T at the coolant inlet is greater than or equal to the lower limit set temperature T1, the fuel cell system controller controls the thermostatic valve 11 so that the coolant from the coolant outlet of the stack module passes through the thermostatic valve 11, the evaporator 4, the radiator 5 and the water pump and then returns to the coolant inlet of the stack module, forming a large cooling circuit.

[0058] The thermostatic valve 11 is used to select one of two operating modes: a large cooling circuit mode and a small cooling circuit mode.

[0059] The specific steps of the above energy recovery control method are:

[0060] Step 1: Determine whether to enter the cooling circuit large cycle working mode. If so, proceed to step 2; if not, proceed to step 8;

[0061] Step 2: The heat pump system starts, and the heat pump compressor 2 starts working. The speed N of the heat pump compressor 2 increases or decreases as the coolant inlet temperature T increases or decreases;

[0062] Step 3: Determine whether the coolant temperature T at the coolant inlet is greater than the upper limit set temperature T2. If so, proceed to step 4; if not, return to step 2.

[0063] Step 4: The fan 51 of the radiator 5 is started, and the speed n of the fan 51 is adjusted to increase or decrease as the temperature T increases or decreases;

[0064] Step 5: Determine whether the coolant temperature T at the coolant inlet is less than or equal to the lower limit set temperature T1. If not, return to step 4. If so, proceed to step 6.

[0065] Step 6: The fan 51 of the radiator 5 stops working;

[0066] Step 7: Determine again whether the coolant temperature T at the coolant inlet is less than or equal to the lower limit set temperature T1. If not, return to step 2. If so, proceed to step 8.

[0067] Step 8: The heat pump system is shut down, the heat pump compressor 2 stops working, and the system re-enters the cooling circuit small cycle working mode.

[0068] The energy recovery control method of the fuel cell of the integrated heat pump energy recovery system of the present invention is relatively simple and effective, easy to implement, and can avoid the risk of coolant temperature getting out of control.

[0069] The above embodiments are preferred implementations of the present invention, but the implementations of the present invention are not limited thereto. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention are equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A fuel cell with an integrated heat pump energy recovery system, comprising a fuel cell stack module, a hydrogen supply and hydrogen recovery system, an air supply system and a cooling system, wherein the hydrogen supply and hydrogen recovery system is connected to the hydrogen inlet and hydrogen outlet of the fuel cell stack module, the air supply system is connected to the air inlet and air outlet of the fuel cell stack module, and the cooling system is connected to the coolant inlet and coolant outlet of the fuel cell stack module, wherein the air supply system comprises an air compressor, and the external air is compressed and heated by the air compressor and then sent to the air inlet of the fuel cell stack module, the air compressor is an air compressor with an expander, and the tail exhaust discharged from the air outlet of the fuel cell stack module enters the expander, and the expander is used to recover the energy of the tail exhaust, characterized in that: A heat pump system is provided between the cooling system and the air supply system. The heat pump system absorbs waste heat in the cooling system and heats the exhaust gas discharged from the fuel cell stack module to increase the temperature of the exhaust gas entering the expander, thereby improving the energy recovery efficiency of the expander.

2. A fuel cell integrated with a heat pump energy recovery system according to claim 1, characterized in that: The air compressor with an expander comprises a motor, an air machine head and an expander, wherein the air machine head and the expander are respectively mounted at two ends of a rotating shaft of the motor.

3. A fuel cell with an integrated heat pump energy recovery system according to claim 1 or 2, characterized in that: The heat pump system includes a condenser, a heat pump compressor, a throttling device, an evaporator and a heat medium. The condenser, the heat pump compressor, the throttling device and the evaporator are connected by pipelines to form a circulation path, and the heat medium flows in the circulation path.

4. The fuel cell integrated with a heat pump energy recovery system according to claim 3, characterized in that: The air supply system also includes an air filter, a flow meter, an intercooler, a humidifier, a back pressure valve and a water separator. External air is sent to the air inlet of the stack module through the air filter, the flow meter, the air compressor, the intercooler and the humidifier. The intercooler is connected to the cooling system and obtains coolant from the cooling system. The cooling system includes a thermostatic valve, a radiator, a heater and a water pump. The heat generated by the operation flows out from the coolant outlet and is divided into two paths through the thermostatic valve. One path of coolant passes through the radiator to the water pump, and the other path of coolant passes through the heater to the water pump. The coolant output from the water pump enters the coolant inlet of the fuel cell module to form a circulation.

5. The fuel cell integrated with a heat pump energy recovery system according to claim 4, characterized in that: A condenser is arranged before the inlet of the expander.

6. A fuel cell integrated with a heat pump energy recovery system according to claim 5, characterized in that: The condenser is arranged between the back pressure valve and the water separator.

7. The fuel cell integrated with a heat pump energy recovery system according to claim 5, characterized in that: An evaporator is arranged between the thermostatic valve and the radiator. The coolant of the cooling system flows through the evaporator and exchanges heat with the heat medium in the evaporator. The heat medium coming out of the evaporator enters the condenser after passing through the heat pump compressor. The tail exhaust discharged from the stack module enters the condenser through the back pressure valve and the water separator. The tail exhaust flowing through the condenser exchanges heat with the heat medium flowing through the condenser, so that the temperature of the tail exhaust flowing through the condenser is increased, and the temperature of the tail exhaust entering the expander is increased, thereby improving the energy recovery efficiency of the expander.

8. The fuel cell integrated with a heat pump energy recovery system according to claim 7, characterized in that: A temperature sensor is provided at the coolant inlet of the fuel cell module.

9. A fuel cell integrated with a heat pump energy recovery system according to claim 8, characterized in that: The speed of the heat pump compressor is adjustable.

10. An energy recovery control method for a fuel cell of an integrated heat pump energy recovery system according to claim 8, wherein the fuel cell further comprises a fuel cell system controller, the fuel cell system controller controls the operation of the stack module, the thermostatic valve, the radiator, the heater, the water pump and the heat pump compressor, and the temperature sensor sends a coolant temperature signal at the coolant inlet to the fuel cell system controller; characterized in that: The energy recovery control method is: When the temperature sensor detects that the coolant temperature T at the coolant inlet is lower than the lower limit setting temperature At T1, the fuel cell system controller controls the thermostatic valve so that the coolant from the coolant outlet of the stack module returns to the coolant inlet of the stack module after passing through the thermostatic valve, heater and water pump, forming a small cooling circuit. When the temperature sensor detects that the coolant temperature T at the coolant inlet is greater than or equal to the lower limit set temperature T1, the fuel cell system controller controls the thermostatic valve so that the coolant coming out of the coolant outlet of the stack module passes through the thermostatic valve, evaporator, radiator and water pump and returns to the coolant inlet of the stack module, forming a large cooling circuit. The thermostatic valve is used to select one of the two working modes: large cooling circuit and small cooling circuit.

11. The energy recovery control method for a fuel cell of an integrated heat pump energy recovery system according to claim 10, characterized in that: Specific steps of the energy recovery control method: Step 1: Determine whether to enter the cooling circuit large cycle working mode, if yes, go to step 2; if not, go to step 8; Step 2: The heat pump system starts, the heat pump compressor starts working, and the speed N of the heat pump compressor increases or decreases as the coolant inlet temperature T increases or decreases; Step 3: Determine whether the coolant temperature T at the coolant inlet is greater than the upper limit setting temperature T2. If so, proceed to step 4; if not, return to step 2; Step 4: The fan of the radiator is started, and the fan speed n is adjusted to increase or decrease as the temperature T increases or decreases; Step 5: Determine whether the coolant temperature T at the coolant inlet is less than or equal to the lower limit setting temperature T1. If not, return to step 4. If yes, proceed to step 6. Step 6: The fan of the radiator stops working; Step 7: again determine whether the coolant temperature T at the coolant inlet is less than or equal to the lower limit setting temperature T1, if not, return to step 2, if so, proceed to step 8; Step 8: The heat pump system is shut down, the heat pump compressor stops working, and the cooling circuit small cycle working mode is re-entered.

12. The energy recovery control method for a fuel cell of an integrated heat pump energy recovery system according to claim 11, characterized in that: The lower limit setting temperature T1 and the upper limit setting temperature T2 are between 50 and 80 degrees Celsius.

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