Control method of fuel cell waste heat recovery system and waste heat recovery system

Abstract

The invention relates to the technical field of fuel cells, and particularly provides a control method of a fuel cell waste heat recovery system and the waste heat recovery system. Specifically, the fuel cell waste heat recovery system comprises a fuel cell, a heat exchanger, a heat storage water tank, a water supply pipe and a drain pipe, two ends of the heat exchanger are communicated with the fuel cell and the heat storage water tank, the water supply pipe is communicated with a water source, and two ends of the heat exchanger are communicated with the water supply pipe and the drain pipe. The fuel cell waste heat recovery system has a heat recovery mode and an overflow mode, and the control method comprises the steps that in the process of executing the heat recovery mode, the water temperature of the heat storage water tank is obtained; the overflow mode is selectively switched according to the water temperature of the heat storage water tank. By adding the overflow mode, a radiator for cooling the cooling liquid does not need to be arranged, the electric energy loss is reduced, whether the overflow mode needs to be switched or not can be judged according to the water temperature of the heat storage water tank, and the stability of the temperature of the fuel cell is ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fuel cell, and particularly provides a control method of fuel cell waste heat recovery system and the waste heat recovery system. BACKGROUND

[0002] The fuel cell waste heat recovery system is generally composed of a fuel cell, a fuel supply sub-waste heat recovery system, an oxidant supply sub-waste heat recovery system, a water heat sub-waste heat recovery system and a control sub-waste heat recovery system.

[0003] The commonly used fuel is hydrogen, and the oxidant is air. The operation principle of the fuel cell is that hydrogen and air are respectively supplied to the anode and cathode of the fuel cell. Hydrogen is decomposed into hydrogen ions and electrons on the anode. The hydrogen ions reach the cathode through the electrolyte (such as a proton exchange membrane) between the anode and the cathode. The electrons are conducted to the cathode through an external circuit. Oxygen in the air combines with hydrogen ions and electrons to generate water in the cathode.

[0004] The electrons generate current during the conduction process. At the same time, due to the electrochemical reaction and the internal resistance of the battery, the fuel cell also generates a certain amount of heat. The generated current can be used for external power supply, and the generated heat can be used for external heating.

[0005] The existing fuel cell waste heat recovery system generally needs to set a radiator to cool the cooling liquid. The radiator is cooled by a fan, and the power consumption is large.

[0006] Therefore, there is a need for a new technical solution to solve the above problems in the field. SUMMARY

[0007] The present application aims to solve the above technical problems, i.e., to solve the problem of large power consumption of the existing fuel cell waste heat recovery system.

[0008] In a first aspect, the present application provides a control method of a fuel cell waste heat recovery system, the fuel cell waste heat recovery system comprising a fuel cell, a heat exchanger, a heat storage water tank, a first cooling pipe, a second cooling pipe, a first circulation pipe, a second circulation pipe, a water supply pipe and a drainage pipe,

[0009] The fuel cell has a cooling liquid inlet and a cooling liquid outlet. The heat exchanger has a liquid inlet, a liquid outlet, a water inlet and a drainage outlet. The heat storage water tank has a water outlet and a backwater outlet,

[0010] The first cooling pipe has its two ends connected to the coolant outlet and the coolant inlet, respectively; the second cooling pipe has its two ends connected to the coolant outlet and the coolant inlet, respectively; the first circulation pipe has its two ends connected to the water outlet and the water inlet, respectively; the second circulation pipe has its two ends connected to the drain outlet and the return water outlet, respectively; one end of the water supply pipe is connected to a water source; the other end of the water supply pipe is connected to the water inlet; and one end of the drain pipe is connected to the drain outlet.

[0011] The fuel cell waste heat recovery system has a heat recovery mode and an overflow mode.

[0012] In the heat recovery mode, the hot water storage tank absorbs heat from the coolant through the heat exchanger to lower the coolant temperature. In the overflow mode, water enters the heat exchanger through the water supply pipe and exits through the drain pipe to lower the coolant temperature.

[0013] The control method includes:

[0014] During the execution of the heat recovery mode, the water temperature of the hot water storage tank is obtained;

[0015] The overflow mode is selectively switched according to the water temperature of the hot water storage tank.

[0016] In the preferred embodiment of the control method for the aforementioned fuel cell waste heat recovery system, the step of "selectively switching to the overflow mode according to the water temperature of the hot water storage tank" specifically includes:

[0017] Compare the water temperature with the preset water temperature;

[0018] If the water temperature is greater than or equal to the preset water temperature, then switch to the overflow mode.

[0019] In the preferred embodiment of the control method for the aforementioned fuel cell waste heat recovery system, the step of "selectively switching to the overflow mode according to the water temperature of the hot water storage tank" specifically includes:

[0020] Compare the water temperature with the target heating water temperature;

[0021] If the water temperature is greater than or equal to the target heating water temperature, then switch to the overflow mode.

[0022] In the preferred embodiment of the control method for the aforementioned fuel cell waste heat recovery system, the step of "selectively switching to the overflow mode according to the water temperature of the hot water storage tank" specifically includes:

[0023] The water temperature is compared with the preset water temperature and the target heating water temperature;

[0024] If the water temperature is greater than or equal to the preset water temperature or the water temperature is greater than or equal to the target heating water temperature, then switch to the overflow mode.

[0025] In a preferred embodiment of the control method for the aforementioned fuel cell waste heat recovery system, the control method further includes:

[0026] After the fuel cell is started and runs for a preset time, the stack temperature of the fuel cell is obtained;

[0027] The temperature of the fuel cell stack is compared with a first preset temperature;

[0028] If the temperature of the fuel cell stack is lower than the first preset temperature, then the water temperature of the hot water storage tank is obtained;

[0029] Depending on the water temperature, the fuel cell stack is selectively heated by water from the hot water storage tank.

[0030] In the preferred embodiment of the control method for the aforementioned fuel cell waste heat recovery system, the step of "selectively heating the fuel cell stack with water from the hot water storage tank according to the water temperature" specifically includes:

[0031] Compare the water temperature with the second preset temperature;

[0032] If the water temperature is greater than the second preset temperature, the fuel cell stack is heated by the water in the hot water storage tank.

[0033] In the preferred embodiment of the control method for the aforementioned fuel cell waste heat recovery system, the second preset temperature is greater than or equal to the first preset temperature; or

[0034] The second preset temperature is lower than the first preset temperature, and the absolute value of the difference between the second preset temperature and the first preset temperature is less than the preset value.

[0035] In a preferred embodiment of the control method for the aforementioned fuel cell waste heat recovery system, when the water temperature is not greater than the second preset temperature, the control method further includes:

[0036] The waste heat recovery system of the fuel cell is shut down and an alarm is issued.

[0037] In the preferred embodiment of the control method for the above-mentioned fuel cell waste heat recovery system, the heat exchanger further has an air inlet and an air outlet, the air inlet is connected to the exhaust gas outlet of the fuel cell, and the hot water storage tank can also absorb heat from the exhaust gas through the heat exchanger.

[0038] In a second aspect, the present invention also provides a waste heat recovery system, including a controller configured to perform the control method described above.

[0039] With the above technical solution, the fuel cell waste heat recovery system of the present invention connects the water source to the inlet of the heat exchanger by adding a water supply pipe and connects the drain pipe to the drain pipe of the heat exchanger, so that the fuel cell waste heat recovery system of the present invention has an overflow mode. In this way, there is no need to set up a radiator to dissipate heat and cool the coolant, reducing power loss. In addition, when the heat recovery mode is executed, it can also determine whether to switch to the overflow mode according to the water temperature of the hot water storage tank, so that when the overflow mode needs to be switched, it can be switched to the overflow mode in a timely manner, which helps to ensure the stability of the fuel cell temperature.

[0040] Furthermore, this invention compares the water temperature of the hot water storage tank with the preset water temperature and the target heating water temperature. When the water temperature is greater than or equal to the preset water temperature or the target heating water temperature, it switches to overflow mode. This ensures both the stability of the fuel cell temperature and the user's water requirements, thus improving the user experience.

[0041] Furthermore, this invention helps to ensure stable operation of the fuel cell by heating the fuel cell stack with water from a hot water storage tank during the fuel cell startup phase when the stack temperature does not meet design requirements.

[0042] Furthermore, by setting an air inlet on the heat exchanger that connects to the exhaust outlet of the fuel cell, the hot water storage tank can also absorb heat from the exhaust gas through the heat exchanger, thereby improving the heat recovery and utilization rate. Attached Figure Description

[0043] The preferred embodiments of the present invention are described below with reference to the accompanying drawings, in which:

[0044] Figure 1 This is a schematic diagram of the fuel cell waste heat recovery system of the present invention;

[0045] Figure 2 This is a flowchart of the control method for the fuel cell waste heat recovery system of the present invention;

[0046] Figure 3 This is a flowchart of a first embodiment of the control method for the fuel cell waste heat recovery system of the present invention;

[0047] Figure 4 This is a flowchart of a second embodiment of the control method for the fuel cell waste heat recovery system of the present invention.

[0048] List of reference numerals in the attached diagram:

[0049] 1. Fuel cell; 11. Coolant inlet; 12. Coolant outlet; 13. Exhaust gas outlet;

[0050] 2. Heat exchanger; 21. Air inlet; 22. Air outlet; 23. Liquid inlet; 24. Liquid outlet;

[0051] 31. Water supply pipe; 32. Drainage pipe;

[0052] 4. Hot water storage tank; 41. Water outlet; 42. Water return outlet; 43. Water inlet; 44. Water supply outlet;

[0053] 51. First cooling pipe; 52. Second cooling pipe;

[0054] 6. Exhaust pipe; 61. Main exhaust pipe; 62. First exhaust pipe; 63. Second exhaust pipe;

[0055] 71. First circulation pipe; 72. Second circulation pipe;

[0056] 81. Coolant pump; 82. Circulating water pump;

[0057] 91. First three-way solenoid valve; 92. Second three-way solenoid valve; 93. Third three-way solenoid valve; 94. Fourth three-way solenoid valve. Detailed Implementation

[0058] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0059] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that although the steps of the control method of the present invention are described in a specific order in this application, this order is not restrictive, and those skilled in the art can perform the steps in different orders without departing from the basic principles of the present invention.

[0060] It should be noted that in the description of this invention, terms such as "top," "bottom," "left," and "right," which indicate direction or positional relationships, are based on the direction or positional relationships shown in the accompanying drawings. These are used merely for ease of description and do not indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0061] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "set," "connect," and "install" should be interpreted broadly, for example, referring to a fixed connection, a detachable connection, or an integral connection. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0062] Specifically, the present invention provides a fuel cell waste heat recovery system, such as Figure 1 As shown, the fuel cell waste heat recovery system of the present invention includes a fuel cell 1, a heat exchanger 2, a hot water storage tank 4, and a hot water circulation pipe.

[0063] The fuel cell 1 has an exhaust port 13, a coolant inlet 11, and a coolant outlet 12. The heat exchanger has an air inlet 21, an air outlet 22, a liquid inlet 23, and a liquid outlet 24. The exhaust port 13 is connected to the air inlet 21, and the liquid inlet 23 and the liquid outlet 24 are connected to the coolant outlet 12 and the coolant inlet 11, respectively. The hot water circulation pipe connects the hot water storage tank 4 to the heat exchanger so that the hot water storage tank 4 can absorb heat from the exhaust gas and the coolant.

[0064] The air inlet 21 on the heat exchanger 2 is connected to the exhaust outlet 13 on the fuel cell 1 through the exhaust pipe. The exhaust gas discharged from the exhaust outlet 13 enters the heat exchanger 2 along the exhaust pipe and exchanges heat with the hot water flowing through the heat exchanger 2. Then it is discharged from the air outlet 22 on the heat exchanger 2. The exhaust gas exchanges heat with the hot water and the hot water storage tank 4 absorbs the heat of the exhaust gas.

[0065] Continue reading Figure 1 In this embodiment, the exhaust pipe includes a main exhaust pipe 61, a first branch exhaust pipe 62, and a second branch exhaust pipe 63. The main exhaust pipe 61, the first branch exhaust pipe 62, and the second branch exhaust pipe 63 are connected to the same three-way solenoid valve (denoted as the first three-way solenoid valve 91). The inlet end of the first three-way solenoid valve 91 is connected to the exhaust port 13 of the fuel cell 1 through the main exhaust pipe 61. The first outlet end of the first three-way solenoid valve 91 is connected to the inlet 21 of the heat exchanger 2 through the first branch exhaust pipe 62. The second outlet end of the first three-way solenoid valve 91 is connected to the second branch exhaust pipe 63. The first three-way solenoid valve 91 is provided with a valve core. By controlling the position of the valve core, the inlet end can be connected to the first outlet end or the second outlet end.

[0066] In other words, the exhaust gas can enter the heat exchanger 2 through the first exhaust pipe 62 to exchange heat with the hot water before being discharged, or it can be discharged directly through the second exhaust pipe 63. In this way, if it is not necessary for the hot water storage tank 4 to absorb the heat of the exhaust gas, the main exhaust pipe 61 can be connected to the second exhaust pipe 63 through the first three-way solenoid valve 91, and the exhaust gas can be discharged directly through the second exhaust pipe 63.

[0067] It should be noted that, in practical applications, those skilled in the art can replace the first three-way solenoid valve 91 with a three-way valve, and then install a solenoid valve on the first exhaust pipe 62 and the second exhaust pipe 63 respectively.

[0068] Continue reading Figure 1 The inlet 23 of the heat exchanger 2 is connected to the coolant outlet 12 of the fuel cell 1 via the first cooling pipe 51, and the outlet 24 of the heat exchanger 2 is connected to the coolant inlet 11 of the fuel cell 1 via the second cooling pipe 52. The coolant discharged from the coolant outlet 12 enters the heat exchanger 2 along the first cooling pipe 51, exchanges heat with the hot water flowing through the heat exchanger 2, and then exits from the outlet 24 of the heat exchanger 2 and enters the second cooling pipe 52, then flows back to the fuel cell 1 along the second cooling pipe 52. Heat exchange occurs between the hot water and the coolant, and the hot water storage tank 4 absorbs the heat from the coolant, achieving heat recovery and avoiding heat waste. The water in the hot water storage tank 4 can be used by users, such as for bathing and washing dishes.

[0069] Continue reading Figure 1 A coolant pump 81 is installed on the first cooling pipe 51. The coolant pump 81 is communicatively connected to the controller of the fuel cell waste heat recovery system, and the flow rate of the coolant can be adjusted through the coolant pump 81. Of course, the coolant pump 81 can also be installed on the second cooling pipe 52.

[0070] Continue reading Figure 1 The hot water storage tank 4 has an outlet 41 and a return outlet 42. The hot water circulation pipe includes a first circulation pipe 71 and a second circulation pipe 72. The two ends of the first circulation pipe 71 are connected to the outlet 41 and the inlet of the heat exchanger 2, respectively. The two ends of the second circulation pipe 72 are connected to the return outlet 42 and the outlet of the heat exchanger 2, respectively. The water in the hot water storage tank 4 enters the first circulation pipe 71 through the outlet 41, and then enters the heat exchanger 2 along the first circulation pipe 71 to exchange heat with the exhaust gas and coolant flowing through the heat exchanger 2. The water discharged from the heat exchanger 2 enters the second circulation pipe 72, and then flows back to the hot water storage tank 4 along the second circulation pipe 72. The temperature in the hot water storage tank 4 gradually increases.

[0071] The outlet 41 is preferably located at the bottom or near the bottom of the hot water storage tank 4, and the return outlet 42 is preferably located at the top or near the top of the hot water storage tank 4, so that the water temperature in the hot water storage tank gradually increases from bottom to top.

[0072] Continue reading Figure 1A circulating water pump 82 is installed on the first circulation pipe 71. The circulating water pump 82 is also connected to the controller of the fuel cell waste heat recovery system, and the flow rate of the hot water can be adjusted through the circulating water pump 82. Of course, in practical applications, those skilled in the art can also install the circulating water pump 82 on the second circulation pipe 72.

[0073] Preferably, the fuel cell waste heat recovery system of this embodiment further includes an electric heating device, which is installed in the hot water storage tank 4 and can heat the water in the hot water storage tank 4.

[0074] It should be noted that, in practical applications, those skilled in the art can also set up two independent heat exchangers, referred to as the first heat exchanger and the second heat exchanger. The air inlet and outlet are located on the first heat exchanger, and the liquid inlet and outlet are located on the second heat exchanger. Two hot water circulation pipes are also set up, referred to as the first hot water circulation pipe and the second hot water circulation pipe. The first hot water circulation pipe connects the hot water storage tank 4 to the first heat exchanger, and the water in the first hot water circulation pipe exchanges heat with the exhaust gas in the first heat exchanger. The second hot water circulation pipe connects the hot water storage tank 4 to the second heat exchanger, and the water in the second hot water circulation pipe exchanges heat with the cooling water in the second heat exchanger.

[0075] In addition, it should be noted that those skilled in the art may also eliminate the air inlet and outlet on the heat exchanger, that is, not recover the heat of the exhaust gas, but only recover the heat of the coolant through the hot water storage tank.

[0076] Preferably, such as Figure 1 As shown, the fuel cell waste heat recovery system of the present invention also includes a water supply pipe 31 and a drain pipe 32, wherein one end of the water supply pipe 31 is connected to a water source, the other end of the water supply pipe 31 is connected to the water inlet of the heat exchanger 2, and one end of the drain pipe 32 is connected to the drain outlet of the heat exchanger 2.

[0077] For example, the water supply pipe 31 is connected to the municipal water supply, specifically to the faucet in the user's home. Water enters the heat exchanger 2 through the water supply pipe 31, exchanges heat with the coolant flowing through the heat exchanger 2, absorbs the heat of the coolant, and is finally discharged through the drain pipe 32.

[0078] In other words, the fuel cell waste heat recovery system of the present invention has a heat recovery mode and an overflow mode. In the heat recovery mode, the hot water tank 4 absorbs heat from the coolant through the heat exchanger 2 to reduce the temperature of the coolant. In the overflow mode, water is introduced into the heat exchanger 2 through the water supply pipe 31 and discharged through the drain pipe 32 to reduce the temperature of the coolant.

[0079] For example, such as Figure 1As shown, heat exchanger 2 is provided with an inlet and a outlet. A three-way solenoid valve (denoted as the second three-way solenoid valve 92) is installed between the water supply pipe 31, the first circulation pipe 71 and the inlet of heat exchanger 2. The three ports of the second three-way solenoid valve 92 are respectively connected to the water supply pipe 31, the first circulation pipe 71 and the inlet of heat exchanger 2. A three-way solenoid valve (denoted as the third three-way solenoid valve 93) is also installed between the outlet pipe 32, the second circulation pipe 72 and the outlet of heat exchanger 2. The three ports of the third three-way solenoid valve 93 are respectively connected to the outlet pipe 32, the second circulation pipe 72 and the outlet of heat exchanger 2. The switching between heat recovery mode and overflow mode is realized through the second three-way solenoid valve 92 and the third three-way solenoid valve 93.

[0080] Specifically, in the heat recovery mode, the second three-way solenoid valve 92 connects the first circulation pipe 71 to the inlet of the heat exchanger 2, and the third three-way solenoid valve 93 connects the second circulation pipe 72 to the outlet of the heat exchanger 2. In the overflow mode, the second three-way solenoid valve 92 connects the water supply pipe 31 to the inlet of the heat exchanger 2, and the third three-way solenoid valve 93 connects the drain pipe 32 to the outlet of the heat exchanger 2.

[0081] Continue reading Figure 1 The hot water storage tank 4 is also equipped with a water supply port 44 and a water replenishment port 43. The hot water in the hot water storage tank 4 is supplied to the user through the water supply port 44, and the water replenishment port 43 is also connected to the faucet. Water is replenished to the hot water storage tank 4 through the water replenishment port 43. A fourth three-way solenoid valve 94 is provided between the water replenishment port 43, the faucet and the water supply pipe 31. The three ports of the fourth three-way solenoid valve 94 are respectively connected to the water replenishment port 43, the faucet and the water supply pipe 31. The fourth three-way solenoid valve 94 can connect the water replenishment port 43 to the faucet to replenish water to the hot water storage tank 4, and can also connect the water supply pipe 31 to the faucet to supply water to the heat exchanger 2.

[0082] Based on the fuel cell waste heat recovery system described above, this invention also provides a control method for the fuel cell waste heat recovery system, such as... Figure 2 As shown, the control method of the present invention includes the following steps:

[0083] S100: During the execution of the heat recovery mode, the water temperature To of the hot water storage tank is obtained;

[0084] For example, one or more temperature sensors can be installed inside the hot water storage tank to detect the water temperature in the tank.

[0085] S200: Selectively switches to overflow mode based on the water temperature To of the hot water storage tank.

[0086] By acquiring the water temperature To of the hot water tank during the heat recovery mode, it can be determined whether the water in the hot water tank can continue to be used for heat exchange with the coolant. In order to switch to overflow mode in time when heat exchange with the coolant cannot be carried out through the water in the hot water tank, it is beneficial to ensure the stability of the fuel cell temperature.

[0087] Preferred Example 1, such as Figure 3 As shown, step S200, "selectively switching to overflow mode according to the water temperature To of the hot water storage tank," specifically includes:

[0088] S210: Compare the hot water temperature To of the hot water storage tank with the preset water temperature Tn;

[0089] S220: If the water temperature To in the hot water storage tank is greater than or equal to the preset water temperature Tn, switch to overflow mode.

[0090] The preset water temperature Tn is related to the highest water temperature Tg that the hot water storage tank can reach by absorbing the heat generated by the fuel cell. Specifically, Tn ≤ Tg, that is, Tn can be equal to Tg or less than Tg. Of course, it is preferable to make Tn < Tg, which is more conducive to ensuring the stability of the fuel cell temperature.

[0091] For example, if the hot water storage tank can reach a maximum water temperature of Tg = 60℃ by absorbing the heat generated by the fuel cell, then the preset water temperature Tn can be set to 50℃ to 60℃.

[0092] When To ≥ Tn, it indicates that the hot water tank can no longer absorb heat from the coolant or absorbs too little heat, making it impossible for the coolant temperature to meet the stack temperature requirements. In this case, it is necessary to switch to overflow mode in time to absorb heat from the coolant through municipal cold water in order to reduce the coolant temperature.

[0093] When To < Tn, the overflow mode is not switched to, and the heat recovery mode continues to be executed to avoid heat waste.

[0094] Preferred Example 2, such as Figure 4 As shown, step S200, "selectively switching to overflow mode according to the water temperature To of the hot water storage tank," specifically includes:

[0095] S210: Compare the current water temperature To of the hot water storage tank with the target heating water temperature Tm;

[0096] S220: If the water temperature To in the hot water storage tank is greater than or equal to the target heating water temperature Tm, switch to overflow mode.

[0097] The target heating water temperature Tm is usually set by the user according to their own needs.

[0098] When To≥Tm, it means that the water temperature in the hot water storage tank has reached the target heating water temperature set by the user. If the hot water storage tank continues to absorb heat from the coolant, the water temperature in the hot water storage tank will be too high and affect the user's use. Therefore, it is necessary to switch to overflow mode in time.

[0099] When To < Tm, the overflow mode is not switched to, and the heat recovery mode continues to be executed, which can both avoid heat waste and meet the user's needs.

[0100] Preferred Example 3, step S200, "selectively switching to overflow mode according to the water temperature To of the hot water storage tank" specifically includes:

[0101] S210: Compare the water temperature To of the hot water storage tank with the preset water temperature Tn and the target heating water temperature Tm;

[0102] S220: If the water temperature To of the hot water storage tank is greater than or equal to the preset water temperature Tn or the water temperature To of the hot water storage tank is greater than or equal to the target heating water temperature Tm, then switch to overflow mode.

[0103] In other words, Example 3 is a combination of Example 1 and Example 2 above, with two switching conditions: To≥Tn and To≥Tm. As long as one of the switching conditions is met, it switches to overflow mode. Only when To<Tn and To<Tm will it continue to maintain heat recovery mode.

[0104] Preferably, the control method of the present invention further includes:

[0105] After the fuel cell is started and has been running for a preset time, the stack temperature Td of the fuel cell is obtained;

[0106] Compare the stack temperature Td with the first preset temperature T1;

[0107] If the fuel cell stack temperature Td is less than the first preset temperature T1, then obtain the water temperature Ts of the hot water storage tank;

[0108] Based on the water temperature Ts, the fuel cell stack is selectively heated by water from the hot water storage tank.

[0109] The first preset temperature T1 is the theoretical temperature of the fuel cell stack when the fuel cell is running stably. After the fuel cell is started and runs for a preset time, the fuel cell is theoretically in a stable operating state. At this time, the stack temperature Td is obtained. If Td < T1, it means that the stack temperature is too low and does not meet the design requirements. In this case, it is possible to consider heating the fuel cell's electric propulsion with water from the hot water storage tank. Of course, before heating the fuel cell's electric propulsion with water from the hot water storage tank, it is necessary to first determine whether the water temperature of the hot water storage tank meets the requirements.

[0110] Preferably, the step of "selectively heating the fuel cell stack with water from the hot water storage tank according to the water temperature Ts" specifically includes:

[0111] Compare the water temperature Ts with the second preset temperature T2;

[0112] If the water temperature Ts is greater than the second preset temperature T2, the fuel cell stack is heated by the water in the hot water storage tank.

[0113] When Ts > T2, it indicates that the water temperature in the hot water storage tank meets the requirements, and the water in the hot water storage tank can be used to heat the electric propeller of the fuel cell. Specifically, the coolant pump and circulating water pump are started, and the coolant absorbs the heat from the water in the hot water storage tank, and then transfers the heat to the electric propeller of the fuel cell to increase the temperature of the fuel cell stack.

[0114] Of course, if the water temperature Ts is less than or equal to the second preset temperature T2, it indicates that the water temperature in the hot water storage tank does not meet the requirements and the fuel cell stack cannot be heated by the water in the hot water storage tank. In this case, it is preferable to stop the fuel cell waste heat recovery system and issue an alarm.

[0115] It should be noted that the second preset temperature T2 can be greater than the first preset temperature T1, or the second preset temperature T2 can be equal to the first preset temperature T1, or the second preset temperature T2 can be less than the first preset temperature T1. However, the absolute value of the difference between the second preset temperature T2 and the first preset temperature T1 is less than the preset value A, that is, T2 > T1 - A. The specific value of the preset value A can be determined experimentally. Of course, it is preferable that T2 ≥ T1.

[0116] Furthermore, it should be noted that the fuel cell waste heat recovery system of the present invention includes a controller, which is configured to execute the control method described above.

[0117] Furthermore, it should be noted that the control method provided in this embodiment can be stored as a program in a computer-readable storage medium. This storage medium includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) or processor to execute partial steps of the methods of the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as a USB flash drive, external hard drive, read-only memory (ROM), random access memory (RAM), magnetic disk, or optical disk.

[0118] Those skilled in the art will understand that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of this application and form different embodiments. For example, any of the claimed embodiments in the claims of this application can be used in any combination.

[0119] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A control method for a fuel cell waste heat recovery system, characterized in that, The fuel cell waste heat recovery system includes a fuel cell, a heat exchanger, a hot water storage tank, a first cooling pipe, a second cooling pipe, a first circulation pipe, a second circulation pipe, a water supply pipe, and a drain pipe. The fuel cell has a coolant inlet and a coolant outlet, the heat exchanger has a liquid inlet, a liquid outlet, a water inlet, and a drain outlet, and the hot water storage tank has a water outlet and a water return outlet. The first cooling pipe has its two ends connected to the coolant outlet and the coolant inlet, respectively; the second cooling pipe has its two ends connected to the coolant outlet and the coolant inlet, respectively; the first circulation pipe has its two ends connected to the water outlet and the water inlet, respectively; the second circulation pipe has its two ends connected to the drain outlet and the return water outlet, respectively; one end of the water supply pipe is connected to a water source; the other end of the water supply pipe is connected to the water inlet; and one end of the drain pipe is connected to the drain outlet. The fuel cell waste heat recovery system has a heat recovery mode and an overflow mode. In the heat recovery mode, the hot water storage tank absorbs heat from the coolant through the heat exchanger to lower the coolant temperature. In the overflow mode, water enters the heat exchanger through the water supply pipe and exits through the drain pipe to lower the coolant temperature. The control method includes: During the execution of the heat recovery mode, the water temperature of the hot water storage tank is obtained; The overflow mode is selectively switched according to the water temperature of the hot water storage tank.

2. The control method for the fuel cell waste heat recovery system according to claim 1, characterized in that, The step of "selectively switching to the overflow mode based on the water temperature of the hot water storage tank" specifically includes: Compare the water temperature with the preset water temperature; If the water temperature is greater than or equal to the preset water temperature, then switch to the overflow mode.

3. The control method for the fuel cell waste heat recovery system according to claim 1, characterized in that, The step of "selectively switching to the overflow mode based on the water temperature of the hot water storage tank" specifically includes: Compare the water temperature with the target heating water temperature; If the water temperature is greater than or equal to the target heating water temperature, then switch to the overflow mode.

4. The control method for the fuel cell waste heat recovery system according to claim 1, characterized in that, The step of "selectively switching to the overflow mode based on the water temperature of the hot water storage tank" specifically includes: The water temperature is compared with the preset water temperature and the target heating water temperature; If the water temperature is greater than or equal to the preset water temperature or the water temperature is greater than or equal to the target heating water temperature, then switch to the overflow mode.

5. The control method for the fuel cell waste heat recovery system according to claim 1, characterized in that, The control method further includes: After the fuel cell is started and runs for a preset time, the stack temperature of the fuel cell is obtained; The temperature of the fuel cell stack is compared with a first preset temperature; If the temperature of the fuel cell stack is lower than the first preset temperature, then the water temperature of the hot water storage tank is obtained; Depending on the water temperature, the fuel cell stack is selectively heated by water from the hot water storage tank.

6. The control method for the fuel cell waste heat recovery system according to claim 5, characterized in that, The step of "selectively heating the fuel cell stack with water from the hot water storage tank according to the water temperature" specifically includes: Compare the water temperature with the second preset temperature; If the water temperature is greater than the second preset temperature, the fuel cell stack is heated by the water in the hot water storage tank.

7. The control method for the fuel cell waste heat recovery system according to claim 6, characterized in that, The second preset temperature is greater than or equal to the first preset temperature; or The second preset temperature is lower than the first preset temperature, and the absolute value of the difference between the second preset temperature and the first preset temperature is less than the preset value.

8. The control method for the fuel cell waste heat recovery system according to claim 5, characterized in that, When the water temperature is not greater than the second preset temperature, the control method further includes: The waste heat recovery system of the fuel cell is shut down and an alarm is issued.

9. The control method for a fuel cell waste heat recovery system according to any one of claims 1 to 8, characterized in that, The heat exchanger also has an air inlet and an air outlet. The air inlet is connected to the exhaust gas outlet of the fuel cell, and the hot water storage tank can also absorb heat from the exhaust gas through the heat exchanger.

10. A waste heat recovery system, comprising a controller, characterized in that, The controller is configured to perform the control method according to any one of claims 1 to 9.

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