A temperature control method for a proton exchange membrane fuel cell stack for a vehicle

Abstract

The present invention discloses a temperature control method for a proton exchange membrane fuel cell stack for a vehicle. The method targets a fuel cell cooling circulation loop including a coolant circulation pump and a radiator with a cooling fan. The method uses measured temperature data to predict data at the next moment in the future, makes a judgment in advance and makes a control operation to avoid a "control delay" phenomenon that causes the set temperature and the set temperature difference to be exceeded. The method adjusts the coolant circulation pump and the cooling fan in real time according to the cooling demand, thereby ensuring that the coolant temperature and the temperature difference are controlled within the set range and avoiding excessive power consumption and energy waste.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and in particular to a temperature control method for a proton exchange membrane fuel cell stack for a vehicle. Background Art

[0002] In order to ensure that the proton exchange membrane fuel cell works at the best performance state, the fuel cell stack must be kept in a certain temperature range, and the uniformity of the temperature distribution inside the stack must be ensured. If the temperature distribution gradient inside the stack is large, it will accelerate the loss of the stack and reduce the service life of the stack. At present, automotive fuel cell systems generally use a circulating pump to drive the coolant circulation to cool the fuel cell stack, and then dissipate the heat to the atmosphere through the radiator. By controlling the temperature of the coolant entering and leaving the stack and the temperature difference of the coolant entering and leaving the stack, the stack is kept in the optimal operating temperature range and the temperature distribution inside the stack is ensured to be uniform. Therefore, the temperature control method is extremely important. If the coolant circulation pump is turned on too small and the radiator fan is turned on too small, it is easy to cause the temperature distribution gradient inside the stack to be large and the temperature of the stack to exceed the set temperature. If the coolant circulation pump is turned on too large and the radiator fan is turned on too large, it is easy to cause the temperature of the stack to be lower than the set temperature; and the coolant circulation pump and the radiator fan need to be driven by power, which will increase energy consumption and reduce the energy efficiency of the entire system. As driving conditions continue to change, the heat generated by the fuel cell is also changing, and the cooling requirements are also changing, making the efficient control of the temperature of the fuel cell stack complicated.

[0003] In addition, during the actual engineering application, it takes a certain amount of time for the coolant temperature to enter the next control state from the previous control state, that is, the "control delay" phenomenon occurs. Due to the "control delay" phenomenon, after the temperature of the coolant at the inlet and outlet of the stack triggers the control system to respond, it will continue to rise or fall in an "inertial" trend for a certain period of time, thereby exceeding the set range. Therefore, there is an urgent need for an efficient stack temperature control method that can effectively control the stack temperature and solve the problems caused by the "control delay" phenomenon. It can also continuously adjust the coolant circulation pump, fan, etc. according to the cooling needs to reduce energy consumption requirements, thereby improving the energy efficiency of the entire system. Summary of the invention

[0004] The purpose of the present invention is to provide a temperature control method for a proton exchange membrane fuel cell stack for a vehicle, so as to solve one or more technical problems existing in the prior art and at least provide a beneficial choice or create conditions.

[0005] The technical solutions adopted to solve the above technical problems are:

[0006] The present invention provides a method for controlling the temperature of a proton exchange membrane fuel cell stack for a vehicle, which is directed to a fuel cell cooling circulation loop including a coolant circulation pump (100) and a radiator (400) with a cooling fan (300);

[0007] Set the stack inlet coolant temperature to Tin, the stack outlet coolant temperature to Tout, the stack inlet and outlet coolant temperature difference to △Tmax and △Tmin, the coolant temperature upper limit to Tmax and lower limit to Tmin; "1" in the temperature symbol represents the previous moment, "2" represents the current moment, and "3" represents the next moment; the time interval between the next moment and the current moment is equal to the time interval between the current moment and the previous moment;

[0008] The specific control steps of adjusting the gear control (Tout2-Tin2) of the coolant circulation pump are as follows:

[0009] S1. Using Tin1, Tout1, Tin2, and Tout2, the initial calculated values ​​Tout3' and Tin3' are calculated by linear interpolation method. The calculation formula is: Tout3' = 2*Tout2-Tout1, Tin3' = 2*Tin2-Tin1;

[0010] S2, after correction, Tout3 and Tin3 are obtained, and the correction formula is: Tout3 = a*Tout3', Tin3 = b*Tin3';

[0011] S3. Determine the relationship between (Tout3-Tin3) and (△Tmax-d) and (△Tmin+e):

[0012] If (Tout3-Tin3)≥(△Tmax-d), the coolant circulation pump is increased by one gear, and after the set time, it returns to S1;

[0013] If (Tout3-Tin3)≤(△Tmin+e), the coolant circulation pump will be reduced by one gear, and after the set time, it will return to S1.

[0014] As a further improvement of the above technical solution, the range of a and b is 0-3, and the range of d and e is 0-2. In order to consider that the actual inlet and outlet temperatures of the fuel cell stack do not change completely linearly, correction coefficients a and b are set, and the range is 0-3. The offset coefficients d and e are set to reduce the possibility that the actual temperature reaches the set upper and lower temperature limits.

[0015] As a further improvement of the above technical solution, in step S3, if (△Tmin+e)<(Tout3-Tin3)<(△Tmax-d), the coolant circulation pump has no further operation, and returns to S1 after the temperature monitoring time interval.

[0016] By measuring the inlet and outlet coolant temperatures of the stack at the previous moment, measuring the inlet and outlet coolant temperatures of the stack at the current moment, using the linear interpolation method, respectively calculate the inlet and outlet coolant temperatures of the stack at the next moment, and after correction using the correction variable, the difference obtained by subtracting the final calculated inlet coolant temperature from the final calculated outlet coolant temperature of the stack is compared with the set inlet and outlet coolant temperature difference of the stack. If it is greater than or equal to the upper limit of the inlet and outlet coolant temperature difference of the stack after the offset, the large coolant circulation pump is turned on; if it is less than or equal to the lower limit of the inlet and outlet coolant temperature difference of the stack after the offset, the small coolant circulation pump is turned on; if it is less than the upper limit of the inlet and outlet coolant temperature difference of the stack after the offset, and greater than the lower limit of the inlet and outlet coolant temperature difference of the stack after the offset, the coolant circulation pump remains in its original state without further operation.

[0017] Utilize the measured temperature data to predict the data at the next moment in the future, make judgments in advance and make control operations on the coolant circulation pump to avoid "control delay" and exceeding the set temperature difference.

[0018] As a further improvement of the above technical solution, in step S3, the time interval is set to c*△t, and the range of c is 1-10. The temperature monitoring time interval is △t, and its value is specified according to engineering experience or experiments. In order to consider the inconsistency between the "control delay" time and the temperature monitoring time △t, a correction coefficient c is set to correct it.

[0019] As a further improvement of the above technical solution, the specific control steps of controlling Tout2 and Tin2 by adjusting the gear position of the cooling fan are as follows:

[0020] The first two steps A1 and A2 are the same as the above-mentioned S1 and S2 respectively;

[0021] A3. Determine the relationship between Tout3 and (Tmax-d'), Tin3 and (Tmin+e'):

[0022] If Tout3≥(Tmax-d') and Tin3≥(Tmin+e'), or Tout3≥(Tmax-d') and Tin3<(Tmin+e'), the cooling fan will increase by one gear, and after the set time, it will return to A1;

[0023] If Tout3<(Tmax-d') and Tin3<(Tmin+e'), the cooling fan will reduce one gear and return to A1 after the set time.

[0024] As a further improvement of the above technical solution, the range of d' and e' is 0-3.

[0025] The offset coefficient d' and the offset coefficient e' are set to reduce the possibility that the actual temperature reaches the set upper and lower temperature limits.

[0026] As a further improvement of the above technical solution, if Tout3<(Tmax-d') and Tin3≥(Tmin+e'), the cooling fan has no further operation, and returns to A1 after the temperature monitoring time interval.

[0027] The stack inlet and outlet coolant temperatures at the previous time interval are measured, and the stack inlet and outlet coolant temperatures at the current time interval are measured, and the stack inlet and outlet coolant temperatures at the next time interval are calculated using the linear interpolation method; after correction using the correction variable, the coolant temperature is compared with the set coolant temperature upper limit and the set coolant temperature lower limit after the offset; if the calculated coolant outlet temperature is greater than or equal to the set coolant temperature upper limit after the offset, the cooling fan is turned on; if the calculated coolant outlet temperature is less than the set coolant temperature upper limit after the offset, and the calculated coolant inlet temperature is less than the set coolant temperature lower limit after the offset, the cooling fan is turned on; if the calculated coolant outlet temperature is less than the set coolant temperature upper limit after the offset, and the calculated coolant inlet temperature is greater than or equal to the set coolant temperature lower limit after the offset, the cooling fan state is maintained without further operation.

[0028] Utilize the measured temperature data to predict the data at the next moment in the future, make judgments in advance and make control operations on the cooling fan to avoid "control delay" and exceeding the set temperature.

[0029] As a further improvement of the above technical solution, in step A3, the time interval is set to c'*△t, the range of c' is 1-10, and the temperature monitoring time interval is △t, whose value is specified according to engineering experience or experiments. In order to consider the inconsistency between the "control delay" time and the temperature monitoring time △t, a correction coefficient c' is set for correction.

[0030] As a further improvement of the above technical solution, the ΔTmax and ΔTmin are not related to the Tmax and Tmin.

[0031] As a further improvement of the above technical solution, temperature sensors are provided at the inlet and outlet of the fuel cell stack.

[0032] The beneficial effects of the present invention are: using the measured temperature data to predict the data at the next moment in the future, judging and making control operations in advance, avoiding the "control delay" phenomenon and exceeding the set temperature and set temperature difference, etc., and adjusting the coolant circulation pump and the cooling fan size in real time according to the cooling demand, which not only ensures that the coolant temperature and temperature difference are controlled within the set range, but also avoids excessive power consumption and energy waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The present invention will be further described below in conjunction with the accompanying drawings and embodiments;

[0034] Figure 1 It is a control flow chart of adjusting the gear position of the coolant circulation pump to control the temperature difference of the coolant inlet and outlet of the stack provided by the present invention;

[0035] Figure 2 It is a control flow chart of adjusting the gear position of the cooling fan to control the temperature of the coolant inlet and outlet of the stack provided by the present invention;

[0036] Figure 3 It is a connection diagram of a cooling circulation loop of one embodiment provided by the present invention. DETAILED DESCRIPTION

[0037] This section will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it cannot be understood as a limitation on the scope of protection of the present invention.

[0038] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., and orientations or positional relationships indicated are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0039] In the description of the present invention, if there are words such as "several", it means one or more, "more" means more than two, greater than, less than, exceed, etc. are understood as not including the number, and above, below, within, etc. are understood as including the number.

[0040] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0041] Reference Figure 1 to Figure 3The temperature control method of the vehicle proton exchange membrane fuel cell stack of the present invention is implemented as follows:

[0042] like Figure 3 As shown, the temperature control method of a vehicle proton exchange membrane fuel cell stack of this embodiment is directed to a cooling circulation loop, and the cooling circulation loop of this embodiment includes a coolant circulation pump (100), a radiator (400) with a cooling fan (300), and a fuel cell stack 200. In some other embodiments, the cooling circulation loop may also include other filtering and energy storage devices, etc., and is not limited to the cooling circulation loop of this embodiment.

[0043] Temperature sensors are installed at the inlet and outlet of the fuel cell stack 200 , and the two temperature sensors are respectively a stack outlet temperature sensor and a stack inlet temperature sensor.

[0044] Among them, the coolant circulation pump 100 drives the coolant to circulate in the loop, takes away the heat in the fuel cell stack 200, enters the radiator 400, and then dissipates it into the atmosphere through heat exchange. In addition, the larger the opening of the coolant circulation pump 100, the greater the coolant flow rate, and the smaller the difference between the temperature measured by the stack outlet temperature sensor and the temperature measured by the stack inlet temperature sensor; the larger the opening of the cooling fan 300, the greater the heat dissipated by the radiator 400 into the atmosphere under the condition that the coolant flow rate remains unchanged.

[0045] The fuel cell stack temperature control method of this embodiment uses the adjustment of the coolant circulation pump 100 gear position to control the stack inlet and outlet coolant temperature difference, and uses the adjustment of the cooling fan 300 gear position to control the stack inlet and outlet coolant temperature.

[0046] The variables involved in this embodiment include the coolant temperature measured at the inlet and outlet of the stack at different times, the calculated coolant temperature at the inlet and outlet of the stack, the time interval, the set upper limit of the coolant temperature, the set lower limit of the coolant temperature, the set upper limit of the coolant temperature difference at the inlet and outlet of the stack, the set lower limit of the coolant temperature difference at the inlet and outlet of the stack, the correction variable, the 100 gear of the coolant circulation pump, the 300 gear of the cooling fan, etc. Among them, the controlled variables are the coolant temperature measured at the inlet and outlet of the stack and the coolant temperature difference at the inlet and outlet of the stack. Among them, the action variables are the 100 gear of the coolant circulation pump and the 300 gear of the cooling fan; the correction variables are set according to engineering experience or experiments. The designated variables are the set upper limit of the coolant temperature, the set lower limit of the coolant temperature, the set upper limit of the coolant temperature difference at the inlet and outlet of the stack, and the set lower limit of the coolant temperature difference at the inlet and outlet of the stack.

[0047] Reference Figure 1 and Figure 2, set the upper limit Tmax of the coolant temperature, set the lower limit Tmin of the coolant temperature, set the upper limit △Tmax of the temperature difference between the inlet and outlet of the stack coolant, and set the lower limit △Tmin of the temperature difference between the inlet and outlet of the stack coolant. In particular, the set upper limit △Tmax of the temperature difference between the inlet and outlet of the stack coolant and the set lower limit △Tmin of the temperature difference between the inlet and outlet of the stack coolant are not related to the set upper limit Tmax of the coolant temperature and the set lower limit Tmin of the coolant temperature. Among them, through the control method provided by the present invention, each temperature does not exceed the set value.

[0048] The measured variables include: the stack inlet coolant temperature Tin1 at the previous moment, the stack outlet coolant temperature Tout1 at the previous moment, the stack inlet coolant temperature Tin2 at the current moment, and the stack outlet coolant temperature Tout2 at the current moment.

[0049] The calculated variables include: the initial calculated value Tout3' of the stack outlet coolant temperature, the initial calculated value Tin3' of the stack inlet coolant temperature, the corrected calculated value Tout3 of the stack outlet coolant temperature, and the corrected calculated value Tin3 of the stack inlet coolant temperature.

[0050] Among them, "1" in the symbol representing temperature represents the previous moment, "2" represents the current moment, and "3" represents the next moment. In addition, the time interval is △t, and its value is specified based on engineering experience or experiments.

[0051] The correction variables include: correction coefficient a, correction coefficient b, correction coefficient c, correction coefficient c', offset coefficient d, offset coefficient e, offset coefficient d', and offset coefficient e'. The above correction variable values ​​are specified based on engineering experience or experiments.

[0052] In this embodiment, the specific control strategy for controlling the temperature difference (Tout2-Tin2) between the inlet and outlet coolant of the stack by adjusting the gear position of the coolant circulation pump 100 is as follows:

[0053] S1, using the last moment stack inlet coolant temperature Tin1, the last moment stack outlet coolant temperature Tout1, the current moment stack inlet coolant temperature Tin2, the current moment stack outlet coolant temperature Tout2, use linear interpolation method to calculate the stack outlet coolant temperature initial calculation value Tout3' and the stack inlet coolant temperature initial calculation value Tin3', wherein the calculation formula is: Tout3'=2*Tout2-Tout1, Tin3'=2*Tin2-Tin1;

[0054] S2. After correction, the calculated value Tout3 of the outlet coolant temperature of the stack and the calculated value Tin3 of the inlet coolant temperature of the stack are obtained. The correction formula is: Tout3 = a*Tout3', Tin3 = b*Tin3';

[0055] S3. Determine the relationship between (Tout3-Tin3) and (△Tmax-d) and (△Tmin+e):

[0056] If (Tout3-Tin3)≥(△Tmax-d), the coolant circulation pump 100 is increased by one gear, and after a time interval c*△t, the process returns to step S1 to start the next cycle;

[0057] If (Tout3-Tin3)≤(△Tmin+e), the coolant circulation pump 100 is reduced by one gear, and after a time interval c*△t, the process returns to step S1 to start the next cycle. If the coolant circulation pump 100 has been reduced to the minimum limited gear, the gear is no longer reduced;

[0058] If (△Tmin+e)<(Tout3-Tin3)<(△Tmax-d), the coolant circulation pump 100 is not allowed to operate further, and after a time interval △t, it returns to step S1 to start the next cycle.

[0059] In order to consider that the actual stack inlet and outlet temperatures do not change completely linearly, correction coefficients a and b are set, and the range is 0-3. Offset coefficients d and e are set to reduce the possibility that the actual temperature reaches the set upper and lower temperature limits, and the range is 0-2.

[0060] This embodiment measures the inlet and outlet coolant temperature of the stack at the previous moment, measures the inlet and outlet coolant temperature of the stack at the current moment, and uses the linear interpolation method to calculate the inlet and outlet coolant temperature of the stack at the next moment, respectively. After correction using the correction variable, the difference obtained by subtracting the final calculated inlet coolant temperature from the final calculated outlet coolant temperature of the stack is compared with the set inlet and outlet coolant temperature difference of the stack. If it is greater than or equal to the upper limit of the inlet and outlet coolant temperature difference of the stack after the offset, the coolant circulation pump 100 is turned on; if it is less than or equal to the lower limit of the inlet and outlet coolant temperature difference of the stack after the offset, the coolant circulation pump 100 is turned on; if it is less than the upper limit of the inlet and outlet coolant temperature difference of the stack after the offset, and greater than the lower limit of the inlet and outlet coolant temperature difference of the stack after the offset, the coolant circulation pump 100 remains in its original state without further operation.

[0061] By using the measured temperature data to predict the data at the next moment in the future, the coolant circulation pump 100 is judged and controlled in advance to avoid the "control delay" phenomenon and exceed the set temperature difference.

[0062] The time interval is △t, and its value is specified according to engineering experience or experiments. In order to consider the inconsistency between the "control delay" time and the temperature monitoring time △t, a correction coefficient c is set to correct it, and the range of c is 1-10.

[0063] In this embodiment, the specific method steps for controlling the inlet and outlet coolant temperatures Tin2 and Tout2 of the stack by adjusting and controlling the cooling fan 300 are as follows:

[0064] A1. Using the last moment stack inlet coolant temperature Tin1, the last moment stack outlet coolant temperature Tout1, the current moment stack inlet coolant temperature Tin2, and the current moment stack outlet coolant temperature Tout2, a linear interpolation method is used to calculate the initial calculated value of the stack outlet coolant temperature Tout3' and the initial calculated value of the stack inlet coolant temperature Tin3', wherein the calculation formula is: Tout3'=2*Tout2-Tout1, Tin3'=2*Tin2-Tin1;

[0065] A2. After correction, the corrected calculated value Tout3 of the stack outlet coolant temperature and the corrected calculated value Tin3 of the stack inlet coolant temperature are obtained. The corrected formulas are: Tout3 = a*Tout3', Tin3 = b*Tin3';

[0066] A3. Determine the relationship between Tout3 and (Tmax-d'), Tin3 and (Tmin+e'):

[0067] If Tout3≥(Tmax-d') and Tin3≥(Tmin+e'), or Tout3≥(Tmax-d') and Tin3<(Tmin+e'), the cooling fan 300 increases one gear, and after a time interval c'*△t, returns to step A1 to start the next cycle;

[0068] If Tout3<(Tmax-d') and Tin3<(Tmin+e'), the cooling fan 300 is reduced by one gear, and after a time interval c'*△t, the process returns to step A1 and starts the next cycle;

[0069] If Tout3<(Tmax-d') and Tin3≥(Tmin+e'), the cooling fan 300 does not need to be further operated, and after a time interval △t, the process returns to step A1 to start the next cycle.

[0070] The offset coefficient d' and the offset coefficient e' are set to reduce the possibility that the actual temperature reaches the set upper and lower temperature limits. The range of d' and e' is 0-3.

[0071] The time interval is △t, and its value is specified according to engineering experience or experiments. In order to consider the inconsistency between the "control delay" time and the temperature monitoring time △t, a correction coefficient c' is set to correct it, and the range of c' is 1-10.

[0072] In this embodiment, the inlet and outlet coolant temperatures of the stack are measured at the previous time interval, the inlet and outlet coolant temperatures of the stack are measured at the current time interval, and the inlet and outlet coolant temperatures of the stack are calculated respectively at the next time interval by linear interpolation method; after correction by using the correction variable, the inlet and outlet coolant temperatures are compared with the set upper limit of the coolant temperature after the offset and the set lower limit of the coolant temperature after the offset; if the calculated coolant outlet temperature is greater than or equal to the set upper limit of the coolant temperature after the offset, the cooling fan 300 is turned on; if the calculated coolant outlet temperature is less than the set upper limit of the coolant temperature after the offset, and the calculated coolant inlet temperature is less than the set lower limit of the coolant temperature after the offset, the cooling fan 300 is turned on; if the calculated coolant outlet temperature is less than the set upper limit of the coolant temperature after the offset, and the calculated coolant inlet temperature is greater than or equal to the set lower limit of the coolant temperature after the offset, the cooling fan 300 is kept in the state without further operation.

[0073] By using the measured temperature data, the data at the next moment in the future is predicted, and the cooling fan 300 is judged and controlled in advance to avoid the "control delay" phenomenon and exceeding the set temperature.

[0074] In this embodiment, the purpose of setting ΔTmin is to reduce the power of the coolant circulation pump 100 within the allowable temperature gradient inside the fuel cell stack, thereby reducing energy consumption. If ΔTmin approaches zero, the coolant flow rate is large, the coolant circulation pump 100 has a large power, and the energy consumption is high.

[0075] This embodiment uses the measured temperature data to predict the data at the next moment in the future, judges and makes control operations in advance, avoids the "control delay" phenomenon and exceeds the set temperature and the set temperature difference, etc., and adjusts the size of the coolant circulation pump 100 and the cooling fan 300 in real time according to the cooling demand, which ensures that the coolant temperature and the temperature difference are controlled within the set range and avoids excessive power consumption and energy waste.

[0076] The preferred embodiments of the present invention are specifically described above, but the invention is not limited to the embodiments. Those skilled in the art may make various equivalent modifications or substitutions without violating the spirit of the invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A method for controlling the temperature of a proton exchange membrane fuel cell stack for a vehicle, characterized in that: The invention relates to a fuel cell cooling circulation loop including a coolant circulation pump (100) and a radiator (400) with a cooling fan (300); Set the stack inlet coolant temperature to Tin, the stack outlet coolant temperature to Tout, the stack inlet and outlet coolant temperature difference upper limit to △Tmax, lower limit to △Tmin, coolant temperature upper limit to Tmax, lower limit to Tmin; "1" in the temperature symbol represents the previous moment, "2" represents the current moment, and "3" represents the next moment. The specific control steps of adjusting the gear position control (Tout2-Tin2) of the coolant circulation pump (100) are as follows: S1. Using Tin1, Tout1, Tin2, and Tout2, the initial calculated values ​​Tout3' and Tin3' are calculated by linear interpolation method. The calculation formula is: Tout3' = 2*Tout2-Tout1, Tin3' = 2*Tin2-Tin1; S2, after correction, Tout3 and Tin3 are obtained, and the correction formula is: Tout3 = a*Tout3', Tin3 = b*Tin3'; S3. Determine the relationship between (Tout3-Tin3) and (△Tmax-d) and (△Tmin+e): If (Tout3-Tin3)≥(△Tmax-d), the coolant circulation pump (100) is increased by one gear, and after a set time, it returns to S1; If (Tout3-Tin3)≤(△Tmin+e), the coolant circulation pump (100) is reduced by one gear, and after a set time, it returns to S1.

2. A method for controlling the temperature of a proton exchange membrane fuel cell stack for a vehicle according to claim 1, characterized in that: The range of a and b is 0-3, and the range of d and e is 0-2.

3. The temperature control method of a vehicle proton exchange membrane fuel cell stack according to claim 1, characterized in that: In step S3, if (ΔTmin+e)<(Tout3-Tin3)<(ΔTmax-d), the coolant circulation pump (100) has no further operation, and after the temperature monitoring time interval has passed, it returns to S1.

4. A method for controlling the temperature of a proton exchange membrane fuel cell stack for a vehicle according to claim 3, characterized in that: In step S3, the time interval and the temperature monitoring time interval are set to c*Δt, where c ranges from 1 to 10.

5. The temperature control method of a vehicle proton exchange membrane fuel cell stack according to claim 1, characterized in that: The specific control steps of controlling Tout2 and Tin2 by adjusting the gear position of the cooling fan (300) are as follows: The first two steps A1 and A2 are the same as the above-mentioned S1 and S2 respectively; A3. Determine the relationship between Tout3 and (Tmax-d'), Tin3 and (Tmin+e'): If Tout3≥(Tmax-d') and Tin3≥(Tmin+e'), or Tout3≥(Tmax-d') and Tin3<(Tmin+e'), the cooling fan (300) increases by one gear, and after a set time, returns to A1; If Tout3<(Tmax-d') and Tin3<(Tmin+e'), the cooling fan (300) is reduced by one gear, and after a set time, it returns to A1.

6. A method for controlling the temperature of a proton exchange membrane fuel cell stack for a vehicle according to claim 5, characterized in that: The range of d' and e' is 0-2.

7. A method for controlling the temperature of a proton exchange membrane fuel cell stack for a vehicle according to claim 5, characterized in that: If Tout3<(Tmax-d') and Tin3≥(Tmin+e'), the cooling fan (300) will not be further operated, and after the temperature monitoring time interval has passed, the process returns to A1.

8. A method for controlling the temperature of a proton exchange membrane fuel cell stack for a vehicle according to claim 7, characterized in that: In step A3, the time interval is set to c'*Δt, the range of c' is 1-10, and the temperature monitoring time interval is Δt.

9. A method for controlling the temperature of a vehicle proton exchange membrane fuel cell stack according to claim 1, characterized in that: The ΔTmax and ΔTmin are both unrelated to the Tmax and Tmin.

10. A method for controlling the temperature of a proton exchange membrane fuel cell stack for a vehicle according to claim 1, characterized in that: Temperature sensors are provided at the inlet and outlet of the fuel cell stack (200).

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