TWI899915B - Fuel cell cooling system and fuel cell temperature control method - Google Patents

Abstract

The present invention provides a fuel cell cooling system for use in a cryogenic logistics vehicle and includes first and second heat exchange modules, a cooling pump assembly, an electromagnetic valve assembly, and an electronic control unit. The first and second heat exchange modules are used to exchange heat with the air outside the vehicle and within the cryogenic cargo compartment, respectively. The cooling pump assembly is used to circulate the coolant, and the electromagnetic valve assembly is electrically connected to the electronic control unit. The electronic control unit performs a fuel cell temperature control method, which first receives output power adjustment information from the fuel cell system, calculates an estimated coolant temperature based on the information, and determines whether the estimated temperature exceeds a pre-stored temperature range. The electromagnetic valve assembly is then controlled to determine whether the coolant, after cooling through the first heat exchange module, should be cooled through the second heat exchange module, thereby controlling the operating temperature of the fuel cell system.

Description

Fuel cell cooling system and fuel cell temperature control method

The present invention relates to fuel cell vehicles, and more particularly to a fuel cell cooling system and a fuel cell temperature control method for low-temperature logistics vehicles.

Fuel cell systems, due to their high efficiency and zero carbon emissions, are increasingly being adopted by various vehicles to improve fuel efficiency and reduce air pollution. However, the electrical and thermal efficiency of fuel cells is closely linked to the system's operating temperature. Only within the appropriate operating temperature range can a fuel cell system achieve stable output and maximize its effectiveness.

However, existing fuel cell vehicle (FCV) systems are typically integrated with existing vehicle structures. Cooling of the FC systems is achieved by directly retrofitting existing vehicle cooling systems. Limited space limits the size and number of components such as heat exchangers and fans that can be used in the cooling system, making it impossible to effectively control the operating temperature of the FC system, resulting in reduced FC system efficiency.

To address the problem that existing fuel cell vehicles, which rely on directly retrofitting existing vehicle cooling systems to cool their fuel cell systems, are unable to effectively control their operating temperatures, the present invention aims to provide a fuel cell cooling system and fuel cell temperature control method that leverages the characteristics of low-temperature logistics vehicles to assist in controlling the operating temperature of the fuel cell system, thereby improving fuel cell efficiency.

The present invention solves the technical problem by providing a fuel cell cooling system for use in a cryogenic logistics vehicle equipped with a fuel cell system and a cryogenic cargo compartment. The fuel cell cooling system comprises: a first heat exchange module for exchanging heat with the air outside the cryogenic logistics vehicle; a second heat exchange module for exchanging heat with the air inside the cryogenic cargo compartment; a cooling pump assembly for circulating coolant between the fuel cell system and the first heat exchange module; an electromagnetic valve assembly disposed between the first heat exchange module and the second heat exchange module; and An electronic control unit is electrically connected to the electromagnetic valve assembly and stores a temperature range. The electronic control unit is capable of receiving output power adjustment information, calculating an estimated coolant temperature based on the output power adjustment information, and determining whether the estimated temperature is within the temperature range. When the estimated temperature is determined to be within the temperature range, the electronic control unit controls the electromagnetic valve assembly to allow the coolant to flow from the first heat exchange module through the second heat exchange module and back to the fuel cell system.

The fuel cell cooling system includes a regulating valve that is electrically connected to the electronic control unit and can be controlled by the electronic control unit to adjust the flow of coolant to the fuel cell system.

In the fuel cell cooling system, the second heat exchange module includes a heat exchange unit and a fan. The fan of the second heat exchange module is a speed-adjustable fan electrically connected to the electronic control unit and can be controlled by the electronic control unit to adjust its speed.

In the fuel cell cooling system, the first heat exchange module includes a heat exchange unit and a fan. The fan of the first heat exchange module is a speed-adjustable fan electrically connected to the electronic control unit and can be controlled by the electronic control unit to adjust its speed.

The present invention also addresses a technical problem by providing a fuel cell temperature control method for a vehicle equipped with a fuel cell system, a low-temperature cargo compartment, and an electronic control unit. The electronic control unit stores a temperature range. The fuel cell temperature control method, executed in the electronic control unit, comprises: Receiving output power adjustment information from the fuel cell system; Calculating an estimated coolant temperature based on the output power adjustment information; Determining whether the estimated coolant temperature is within the temperature range; When the estimated temperature is determined to be within the temperature range, an electromagnetic valve assembly is controlled to allow the coolant to flow from the fuel cell system through a first heat exchange module, then through a second heat exchange module located in the low-temperature cargo compartment and back to the fuel cell system.

In the fuel cell temperature control method, after the electronic control unit controls the electromagnetic valve assembly to allow the coolant to flow back into the fuel cell system through the second heat exchange module, the electronic control unit adjusts the speed of a fan in the second heat exchange module based on the estimated temperature.

In the fuel cell temperature control method, the electronic control unit activates a regulating valve according to the estimated temperature to adjust the flow of the coolant to the fuel cell system.

In the fuel cell temperature control method, the electronic control unit adjusts the rotation speed of a fan of the first heat exchange module according to the estimated temperature.

The technical measures of the present invention can achieve the following improved performance: 1. The fuel cell cooling system and fuel cell temperature control method of the present invention, when the output power of the fuel cell system is normally maintained constant or adjusted within a small range, coolant is cooled by the conventional first heat exchange module. It is then further forcibly cooled by the second heat exchange module located in the low-temperature cargo compartment, keeping the coolant at a relatively low temperature. Subsequently, when the output power of the fuel cell system is significantly increased, the relatively low-temperature coolant can effectively and quickly transfer excess waste heat generated by the increased output power. This keeps the operating temperature of the fuel cell system under control and prevents it from rising too rapidly. This allows the fuel cell system to maintain good operating efficiency and achieve excellent electrical and thermal efficiency. 2. The fuel cell cooling system and fuel cell temperature control method of the present invention utilize a judgment mechanism within the electronic control unit to prevent the coolant from dissipating heat through the second heat exchange module after the fuel cell system's output power is significantly increased. This prevents the low-temperature compartment's temperature from excessively rising due to the high-temperature coolant, thus protecting items stored at low temperatures within the compartment from damage. This allows the present invention to utilize the low temperature of the compartment to assist in cooling the coolant without compromising the compartment's functionality.

In order to fully understand the technical features and practical effects of the present invention and to implement them according to the content of the invention, the preferred embodiment shown in the drawings is further described in detail as follows:

Figures 1 through 3 illustrate a fuel cell cooling system according to a preferred embodiment of the present invention, which is used in a cryogenic logistics vehicle 90. The cryogenic logistics vehicle 90 is equipped with a fuel cell system 10 and a cryogenic cargo compartment 91. The cryogenic cargo compartment 91 is a storage compartment with an interior temperature lower than ambient temperature, capable of storing fresh food or other goods that require insulation and preservation. The fuel cell cooling system is used to control the temperature of the fuel cell system 10 and includes a cooling pump assembly 20, a first heat exchange module 30, a second heat exchange module 40, an electromagnetic valve assembly 50, and an electronic control unit 60.

The fuel cell system 10 uses hydrogen as fuel to generate electricity. The electricity generated by the fuel cell system 10 can drive the motor to drive the low-temperature logistics vehicle 90 forward, drive the refrigeration system on the low-temperature logistics vehicle 90 to operate to control the temperature of the low-temperature cargo compartment 91, or be used as an auxiliary power source. As shown in Figure 1, the low-temperature logistics vehicle 90 is equipped with a plurality of hydrogen storage tanks 12 to supply hydrogen to the fuel cell system 10. Waste heat is generated during operation. Therefore, as shown in FIG2 , the fuel cell cooling system is provided with a coolant circulation circuit. The cooling pump assembly 20, the first heat exchange module 30, the second heat exchange module 40, and the electromagnetic valve assembly 50 are disposed in the coolant circulation circuit. This allows the coolant to flow through the fuel cell system 10 to dissipate heat, thereby lowering the operating temperature of the fuel cell system 10 and cooling other components of the fuel cell cooling system to dissipate heat from the fuel cell system 10.

As shown in Figures 1 and 2, the cooling pump assembly 20 is used to provide pressure, allowing the coolant to circulate in the coolant circulation pipeline, thereby circulating between the fuel cell system 10 and the first heat exchange module 30. The cooling pump assembly 20 specifically includes a plurality of cooling water pumps 21 connected in series. This ensures that after the coolant is drawn from the fuel cell system 10, there is sufficient pressure to circulate in the coolant circulation pipeline. After cooling through the first heat exchange module 30, the coolant can flow back to the fuel cell system 10 to dissipate heat.

As shown in FIG2 , the first heat exchange module 30 specifically includes a heat exchange unit and a fan, which are defined as a first heat exchange unit 31 and a first fan 32, respectively. The first heat exchange unit 31 refers to a pipe or other structure in the first heat exchange module 30 for the coolant to flow through. The first heat exchange unit 31 is connected to the cooling pump assembly 20. The coolant is pumped by the cooling pump assembly 20 and flows through the first heat exchange unit 31. The first fan 32 is arranged on one side of the first heat exchange unit 31 and is connected to the outside of the low-temperature cargo compartment 91. The air outside the low-temperature logistics vehicle 90 enters through the first fan 32 and exchanges heat with the first heat exchange unit 31, thereby cooling the coolant flowing through the first heat exchange unit 31.

As shown in Figures 1 and 2, the second heat exchange module 40 is located in the low-temperature cargo compartment 91 of the low-temperature logistics vehicle 90. The second heat exchange module 40 also includes a heat exchange unit and a fan, which are defined as a second heat exchange unit 41 and a second fan 42 respectively. The second heat exchange unit 41 refers to the pipeline or other structure in the second heat exchange module 40 for the coolant to flow through. The second fan 42 is located on one side of the second heat exchange unit 41 and can cause the air in the low-temperature cargo compartment 91 to flow, allowing the air in the low-temperature cargo compartment 91 to exchange heat with the second heat exchange unit 41, thereby cooling the coolant flowing through the second heat exchange unit 41.

The detailed structure and configuration of the first heat exchange module 30 and the second heat exchange module 40 may refer to existing heat exchange technology or adopt the heat dissipation system structure of existing vehicles. For example, multiple fans may be provided, and the present invention is not limited thereto.

As shown in FIG2 , the electromagnetic valve assembly 50 includes a first electromagnetic valve 51 and a second electromagnetic valve 52. The first electromagnetic valve 51 is disposed between the first heat exchange unit 31 and the second heat exchange unit 41. The first electromagnetic valve 51 can be controlled to determine whether the coolant passes through the second heat exchange module 40 in the low-temperature cargo compartment 91 after passing through the first heat exchange module 30. The second solenoid valve 52 is disposed between the first solenoid valve 51, the second heat exchange unit 41, and the fuel cell system 10. This allows the coolant to flow from the first solenoid valve 51 through the second solenoid valve 52 back to the fuel cell system 10, or from the first solenoid valve 51 through the second heat exchange unit 41 and then back to the fuel cell system 10 through the second solenoid valve 52.

In other embodiments, a tee may be simply provided at the second electromagnetic valve 52, and a one-way valve may be provided between the tee and the second heat exchange unit 41. Similarly, after the first electromagnetic valve 51 switches the coolant path, the coolant can flow back to the fuel cell system 10 from the corresponding path for heat dissipation. As long as the electromagnetic valve assembly 50 is provided with the first electromagnetic valve 51 and can determine whether the coolant passes through the second heat exchange module 40 after passing through the first heat exchange module 30, the form of the rear end connection path of the electromagnetic valve assembly 50 is not limited to the preferred embodiment of the present invention.

As shown in Figure 3, the electronic control unit 60 is electrically connected to the first solenoid valve 51 and the second solenoid valve 52 and stores a temperature range. In a preferred embodiment of the present invention, the cryogenic logistics vehicle 90 is equipped with a vehicle control unit (VCU) 92. The electronic control unit 60 is electrically connected to the vehicle control unit 92 and can receive relevant command information from the vehicle control unit 92, perform calculations, and compare the calculation results with the temperature range, thereby controlling the first solenoid valve 51 and the second solenoid valve 52 to determine the heat dissipation path of the coolant.

As shown in FIG4A and FIG4B, a flow chart of a fuel cell temperature control method using the fuel cell cooling system is shown. The fuel cell temperature control method is performed during the operation of the cryogenic logistics vehicle 90. As shown in FIG4A, first, an information receiving step S1 is performed: the electronic control unit 60 receives an output power adjustment information of the fuel cell system 10; specifically, when the cryogenic logistics vehicle 90 needs to increase the output power of the fuel cell system 10 (for example, when the cryogenic logistics vehicle 90 accelerates), the vehicle control unit 92 Receiving an output power adjustment command and adjusting the output power may specifically include sending an electrical signal to activate a gas valve to adjust the amount of hydrogen output from the hydrogen storage tank 12 to the fuel cell system 10 to increase the output power. After the vehicle control unit 92 receives the output power adjustment command, it issues output power adjustment information based on the power adjustment command. The electronic control unit 60 receives the output power adjustment information from the vehicle control unit 92 to obtain the current output power of the fuel cell system 10 and the target value for adjusting the output power.

Next, a calculation step S2 is performed: the electronic control unit 60 calculates an estimated temperature of the coolant based on the output power adjustment information. Specifically, fuel cells can draw characteristic curves related to data such as power, efficiency, and temperature based on their properties. The electronic control unit 60 has a built-in calculation formula set based on the above characteristic curve. After receiving the output power adjustment information, the electronic control unit 60 can calculate the estimated temperature of the coolant based on the current output power of the fuel cell system 10. The aforementioned equation is used to calculate the amount of heat currently dissipated by the fuel cell system 10 through the coolant. The target output value is then used to calculate the amount of heat that the fuel cell system 10 will need to dissipate through the coolant after the output power changes. The difference between the two values is then used to calculate the excess waste heat generated by the fuel cell system 10 due to the increased output power. The coolant temperature rise after the output power increase is then estimated using the coolant flow rate and current temperature.

The temperature of the coolant after it passes through the fuel cell system 10 can be obtained by installing a temperature sensor and transmitted to the electronic control unit 60. The coolant flow rate can be sensed by installing a flow sensor in the flow path, and the sensed information can be transmitted to the electronic control unit 60. Alternatively, the electronic control unit 60 can receive speed information of the cooling water pump 21 and estimate the coolant flow rate based on the speed of the cooling water pump 21. Alternatively, the cooling water pump 21 can be a pump with a fixed speed. All of the above methods allow the electronic control unit 60 to obtain the coolant flow rate and, combined with the calculated excess waste heat and the temperature of the coolant after it passes through the fuel cell system 10, calculate the estimated temperature.

A determination step S3 is then performed: the electronic control unit 60 determines whether the estimated temperature of the coolant is within a preset temperature range. After calculating the estimated temperature, the electronic control unit 60 performs a logical operation to determine whether the estimated temperature exceeds the temperature range pre-stored in the electronic control unit 60. This determines the flow direction of the coolant, allowing the coolant to dissipate heat through the appropriate heat dissipation path at the appropriate time.

As shown in FIG4A and FIG4B, when it is determined that the estimated temperature is within the temperature range, a strong cooling step S4 is performed: the electronic control unit 60 controls the electromagnetic valve assembly 50 to allow the coolant to flow from the fuel cell system 10 through the first heat exchange module 30, and then through the second heat exchange module 40 located in the low-temperature cargo compartment 91 and flow back to the fuel cell system 10; when the estimated temperature is within the temperature range, it means that the temperature of the coolant after passing through the fuel cell system 10 is not much different from the temperature after passing through the fuel cell system 10. As shown in FIG5, the electronic control unit 60 generates an electric current. The signal controls the first solenoid valve 51 and the second solenoid valve 52, allowing the coolant to cool down after passing through the first heat exchange module 30. The coolant then passes through the second heat exchange module 40, where it is cooled by the low-temperature air within the low-temperature compartment 91. In this way, after the coolant is normally cooled by passing through the first heat exchange module 30, it is further cooled by passing through the second heat exchange module 40 within the low-temperature compartment 91, forcing the coolant to cool down rapidly. The coolant can then be used to dissipate heat from the fuel cell system 10 again, effectively maintaining the operating temperature of the fuel cell system 10 at a relatively low temperature.

As shown in FIG4A , when the electronic control unit 60 determines that the estimated temperature is not within the temperature range, a normal cooling step S5 is performed: the electronic control unit 60 controls the electromagnetic valve assembly 50 so that the coolant passes through the first heat exchange module 30 and then flows back to the fuel cell system 10 without passing through the second heat exchange module 40. When the estimated temperature exceeds the temperature range, it means that the temperature of the coolant will rise more after passing through the fuel cell system 10. As shown in FIG6 , the electronic control unit 60 now sends an electrical signal to control the first solenoid valve 51 and the second solenoid valve 52, causing the coolant to cool through the first heat exchange module 30 and then flow directly back to the fuel cell system 10 without passing through the second heat exchange module 40. In this way, if the coolant temperature is expected to rise significantly, heat is normally dissipated through the first heat exchange module 30, preventing the temperature in the low-temperature cargo compartment 91 from excessively rising due to the higher-temperature coolant.

According to the above, the fuel cell cooling system of the present invention and the fuel cell temperature control method thereof, when the output power of the fuel cell system 10 is kept constant or adjusted within a small range, the coolant is cooled by the conventional first heat exchange module 30 and then forced to cool by the second heat exchange module 40 located in the low-temperature compartment 91, so that the coolant is controlled at a relatively low temperature. When the output power of the fuel cell system 10 is significantly increased, the coolant at a relatively low temperature can effectively and quickly transfer the excess waste heat generated by the increased output power of the fuel cell system 10. This allows the operating temperature of the fuel cell system 10 to be controlled and prevent it from rising too quickly, thereby maintaining good operating efficiency and achieving excellent electrical and thermal benefits.

Furthermore, after the output power of the fuel cell system 10 is significantly increased, the judgment mechanism of the electronic control unit 60 causes the coolant to no longer be cooled by the second heat exchange module 40 within the low-temperature compartment 91. This prevents the temperature of the low-temperature compartment 91 from excessively rising due to the high-temperature coolant, thereby avoiding damage to items requiring low-temperature storage within the low-temperature compartment 91. This allows the present invention to utilize the low temperature of the low-temperature compartment 91 to assist in cooling the coolant without affecting the function of the low-temperature compartment 91.

As shown in Figures 2 and 3, in a preferred embodiment of the present invention, the cooling system further includes a regulating valve 71. The regulating valve 71 is disposed on the coolant circulation line and located between the second solenoid valve 52 and the fuel cell system 10. The regulating valve 71 is electrically connected to the electronic control unit 60 and can be controlled by the electronic control unit 60 to regulate the flow of coolant from a coolant storage chamber into the coolant circulation line and to the fuel cell system 10. Since the coolant storage chamber used in a vehicle is a conventional technology, it is not shown in the drawings and will not be described in detail.

As shown in FIG4A and FIG4B, in the above-mentioned fuel cell temperature control method, after the strong cooling step S4 and the normal cooling step S5, a first heat dissipation adjustment step S4A and a second heat dissipation adjustment step S5A are respectively performed: the heat dissipation capacity is adjusted according to the estimated temperature; specifically, the first heat dissipation adjustment step S4A and the second heat dissipation adjustment step S5A both include: starting the A regulating valve 71 regulates the flow of coolant to the fuel cell system 10. The electronic control unit 60 calculates the amount of excess waste heat required to be absorbed by the coolant and then controls the regulating valve 71 via an electrical signal to adjust the flow of coolant to the fuel cell system 10. This adjusts the heat dissipation capacity of the fuel cell system 10, thereby more effectively controlling the operating temperature of the fuel cell system 10.

As shown in Figures 4A and 4B, in a preferred embodiment of the present invention, after the forced cooling step S4, the electronic control unit 60 re-performs the aforementioned information receiving step S1 to re-receive the output power adjustment information of the fuel cell system 10. In this way, the electronic control unit 60 can instantly adjust the cooling mechanism of the coolant in response to the output power adjustment of the fuel cell system 10, allowing the coolant to more quickly and immediately transfer excess waste heat generated by the fuel cell system 10, thereby allowing the fuel cell system 10 to operate with better efficiency.

In a preferred embodiment of the present invention, the second fan 42 of the second heat exchange module 40 is a fan with adjustable speed. The second fan 42 is electrically connected to the electronic control unit 60 and can be controlled by the electronic control unit 60 to adjust its speed. Specifically, as shown in FIG4B , the first heat dissipation adjustment step S4A further includes: adjusting the speed of the fan of the second heat exchange module 40 according to the estimated temperature; After calculating the excess waste heat required to be absorbed by the coolant, the control unit 60 adjusts the speed of the second fan 42 to adjust the cooling efficiency of the coolant as it passes through the second heat exchange module 40. This allows the coolant to be effectively cooled in the second heat exchange module 40 and flow back into the fuel cell system 10, thereby improving the heat dissipation capacity of the fuel cell system 10 and more stably controlling the operating temperature of the fuel cell system 10.

In a preferred embodiment of the present invention, the first fan 32 of the first heat exchange module 30 is also a fan with adjustable speed. The first fan 32 is electrically connected to the electronic control unit 60 and can be controlled by the electronic control unit 60 to adjust its speed. Specifically, as shown in Figures 4A and 4B, the first heat dissipation adjustment step S4A and the second heat dissipation adjustment step S5A further include: adjusting the speed of the fan of the first heat exchange module 30 according to the estimated temperature; after the electronic control unit 60 calculates the excess waste heat that the coolant needs to absorb, it adjusts the speed of the first fan 32 to adjust the cooling efficiency of the coolant when passing through the first heat exchange module 30. Like the second fan 42, it can more stably control the operating temperature of the fuel cell system 10.

As shown in Figures 4A and 4B, as described above, the first heat dissipation adjustment step S4A and the second heat dissipation adjustment step S5A include: starting the regulating valve 71 to adjust the flow rate of the coolant according to the estimated temperature, adjusting the speed of the first fan 32 according to the estimated temperature, adjusting the speed of the second fan 42 according to the estimated temperature, and other operational details. When performing the first heat dissipation adjustment step S4A and the second heat dissipation adjustment step S5A, it can be determined based on the estimated temperature whether to perform one of the operational details or all of the operational details simultaneously, and no further restrictions are imposed here.

The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Any equivalent embodiment made by a person having ordinary skill in the relevant technical field, without departing from the scope of the technical solution proposed by the present invention and making partial changes or modifications to the technical content disclosed by the present invention, and without departing from the content of the technical solution of the present invention, still falls within the scope of the technical solution of the present invention.

10: Fuel cell system 12: Hydrogen storage tank 20: Cooling pump assembly 21: Cooling water pump 30: First heat exchange module 31: First heat exchange unit 32: First fan 40: Second heat exchange module 41: Second heat exchange unit 42: Second fan 50: Solenoid valve assembly 51: First solenoid valve 52: Second solenoid valve 60: Electronic control unit 71: Regulating valve 90: Cryogenic logistics vehicle 91: Cryogenic cargo compartment 92: Vehicle control unit S1: Information receiving step S2: Calculation step S3: Judgment step S4: Forced cooling step S4A: First heat dissipation adjustment step S5: Normal cooling step S5A: Second heat dissipation adjustment step

Figure 1 is a schematic diagram of a preferred embodiment of the present invention applied to a cryogenic logistics vehicle. Figure 2 is a schematic diagram of the piping configuration of a preferred embodiment of the present invention. Figure 3 is a circuit block diagram of a preferred embodiment of the present invention. Figures 4A and 4B are flow charts of a fuel cell temperature control method using a preferred embodiment of the present invention. Figures 5 and 6 are schematic diagrams of the operation of a preferred embodiment of the present invention.

10: Fuel cell system 20: Cooling pump assembly 30: First heat exchange module 31: First heat exchange unit 32: First fan 40: Second heat exchange module 41: Second heat exchange unit 42: Second fan 50: Solenoid valve assembly 51: First solenoid valve 52: Second solenoid valve 71: Regulating valve 91: Low-temperature cargo compartment

Claims (9)

A fuel cell cooling system for a cryogenic logistics vehicle equipped with a fuel cell system and a cryogenic cargo compartment. The fuel cell cooling system comprises: a first heat exchange module for exchanging heat with air outside the cryogenic logistics vehicle; a second heat exchange module for exchanging heat with air within the cryogenic cargo compartment; a cooling pump assembly for circulating coolant between the fuel cell system and the first heat exchange module; an electromagnetic valve assembly disposed between the first heat exchange module and the second heat exchange module; and An electronic control unit is electrically connected to the electromagnetic valve assembly and stores a temperature range. The electronic control unit is capable of receiving output power adjustment information, calculating an estimated coolant temperature based on the output power adjustment information, and determining whether the estimated temperature is within the temperature range. When the estimated temperature is determined to be within the temperature range, the electronic control unit controls the electromagnetic valve assembly to allow the coolant to flow from the first heat exchange module through the second heat exchange module and back to the fuel cell system. When the estimated temperature is determined to be outside the temperature range, the electronic control unit controls the electromagnetic valve assembly to allow the coolant to flow directly from the first heat exchange module back to the fuel cell system without passing through the second heat exchange module. The fuel cell cooling system as described in claim 1 includes a regulating valve, which is electrically connected to the electronic control unit and can be controlled by the electronic control unit to regulate the flow of coolant to the fuel cell system. The fuel cell cooling system as described in claim 1, wherein the second heat exchange module includes a heat exchange unit and at least one fan, wherein the fan is a fan with adjustable speed, electrically connected to the electronic control unit, and can be controlled by the electronic control unit to adjust its speed. The fuel cell cooling system as described in claim 1, wherein the first heat exchange module includes a heat exchange unit and at least one fan, the fan is a fan with adjustable speed, electrically connected to the electronic control unit, and can be controlled by the electronic control unit to adjust its speed. A fuel cell temperature control method is applied to a vehicle. The vehicle includes a fuel cell system, a low-temperature cargo compartment, and an electronic control unit. The electronic control unit stores a temperature range. The fuel cell temperature control method is executed in the electronic control unit and includes: receiving output power adjustment information from the fuel cell system; calculating an estimated temperature of a coolant based on the output power adjustment information; determining whether the estimated temperature of the coolant is within the temperature range; if the estimated temperature is determined to be within the temperature range, controlling an electromagnetic valve assembly to cause the coolant to flow from the fuel cell system through a first heat exchange module, then through a second heat exchange module located in the low-temperature cargo compartment, and back to the fuel cell system; When it is determined that the estimated temperature exceeds the temperature range, the electromagnetic valve assembly is controlled to allow the coolant to flow directly back to the fuel cell system from the fuel cell system through a first heat exchange module without passing through the second heat exchange module. A fuel cell temperature control method as described in claim 5, wherein, after the electronic control unit controls the electromagnetic valve assembly to allow the coolant to flow back into the fuel cell system through the second heat exchange module, the electronic control unit adjusts the speed of a fan of the second heat exchange module according to the estimated temperature to adjust the heat exchange efficiency of the second heat exchange module. The fuel cell temperature control method as described in claim 5, wherein the electronic control unit activates a regulating valve based on the estimated temperature to adjust the flow of the coolant to the fuel cell system. A fuel cell temperature control method as described in claim 5, wherein the electronic control unit adjusts the speed of a fan of the first heat exchange module according to the estimated temperature to adjust the heat exchange efficiency of the second heat exchange module. In the fuel cell temperature control method as described in claim 5, after the coolant flows back into the fuel cell system through the second heat exchange module located in the low-temperature cargo compartment, the electronic control unit again receives the output power adjustment information of the fuel cell system.