A fuel cell thermal management system with cold storage function

Abstract

The present invention discloses a fuel cell thermal management system with a cold storage function, comprising: a main fuel cell cooling system that directly dissipates heat from the fuel cell stack through coolant circulation; a cold storage system in which chilled water circulates and exchanges heat with the coolant of the main fuel cell cooling system through a first heat exchanger; a refrigeration system in which a refrigerant circulates and exchanges heat with the chilled water in the cold storage system through a second heat exchanger; this system effectively increases the peak heat dissipation capacity of the existing heat dissipation system of the fuel cell, and can improve the power performance, operation reliability and service life of the fuel cell vehicle.

Description

Technical Field

[0001] The present invention relates to the field of proton exchange membrane fuel cells, and particularly to a fuel cell thermal management system with a cold storage function. Background Art

[0002] A proton exchange membrane fuel cell is a power generation device that converts the chemical energy of fuel (hydrogen) into electrical energy. Due to its advantages such as high efficiency, environmental protection, and strong endurance, it is increasingly used in vehicle power systems. With the development of fuel cell technology, the output power continues to increase, and the heat dissipation problem has increasingly become a bottleneck restricting its development. Under rated conditions, the power generation and heat generation of the fuel cell are approximately 1:1, and its operating temperature is usually between 65-80°C. Compared with the operating temperature of about 105°C of a fuel vehicle, its heat dissipation temperature difference is too small, and the heat dissipation load is large. In application scenarios with a high ambient temperature, over-temperature faults are likely to occur, resulting in the power system limiting power operation, seriously affecting the driving safety and experience.

[0003] Currently, the heat dissipation capacity of fuel cell systems is generally improved from the following three aspects: One is to improve the performance of the radiator and develop a radiator with a higher heat transfer coefficient. Its advantage is that it does not require a larger space, but it depends on the technological progress of the industry and has a high development cost; the second is to increase the operating temperature of the fuel cell stack, but too high a temperature will cause the water content in the fuel cell membrane to rapidly decrease, resulting in performance degradation or even membrane damage; the third is to increase the radiator area. This method requires selecting a larger or more radiators, which not only has higher layout space requirements for the whole vehicle, increases the amount of coolant in the system and thus leads to an increase in weight, but also has an adverse impact on the temperature control of the system in a low-temperature environment. Summary of the Invention

[0004] The purpose of the present invention is to propose a solution for improving the heat dissipation capacity of a fuel cell system that does not occupy a large space and has a low development cost.

[0005] To achieve the above purpose, the present invention proposes a fuel cell thermal management system with a cold storage function, including:

[0006] A fuel cell main cooling system that directly dissipates heat from the fuel cell stack through coolant circulation;

[0007] A cold storage system in which chilled water circulates and exchanges heat with the coolant of the fuel cell main cooling system through a first heat exchanger;

[0008] A refrigeration system in which a refrigerant circulates and exchanges heat with the chilled water in the cold storage system through a second heat exchanger.

[0009] Preferably, the first heat exchanger includes a high-temperature pipeline and a low-temperature pipeline. Among them, the high-temperature pipeline of the first heat exchanger is connected to the main fuel cell cooling system, and the low-temperature pipeline of the first heat exchanger is connected to the cold storage system;

[0010] The second heat exchanger also includes a high-temperature pipeline and a low-temperature pipeline. Among them, the high-temperature pipeline of the second heat exchanger is connected to the cold storage system, and the low-temperature pipeline of the second heat exchanger is connected to the refrigeration system.

[0011] Preferably, the main fuel cell cooling system includes the following components connected by pipelines:

[0012] A first circulating water pump that provides circulating power for the coolant in the main fuel cell cooling system;

[0013] A first temperature sensor, which is arranged upstream of the fuel cell stack and detects the temperature of the coolant entering the fuel cell stack pipeline before entering the stack;

[0014] A radiator, which is connected in parallel with the high-temperature pipeline of the first heat exchanger. Both the radiator and the first heat exchanger are arranged downstream of the fuel cell stack to dissipate heat from the coolant;

[0015] A first three-way valve, which is arranged between the radiator, the first heat exchanger and the fuel cell stack, and controls and distributes the coolant flow through the high-temperature pipelines of the radiator and the first heat exchanger.

[0016] Preferably, the cold storage system includes the following components connected by pipelines:

[0017] A second circulating water pump, which is arranged upstream of the low-temperature pipeline of the first heat exchanger and provides circulating power for the chilled water in the cold storage system;

[0018] A second three-way valve, which is arranged between the low-temperature pipeline of the first heat exchanger and the second circulating water pump, and is used to control the chilled water flow into the low-temperature pipeline of the first heat exchanger;

[0019] A water storage tank, which is arranged downstream of the low-temperature pipeline of the first heat exchanger and stores the chilled water when the chilled water circulation is not required;

[0020] A second temperature sensor, which is arranged at the outlet of the water storage tank and is used to detect the temperature of the chilled water in the cold storage system;

[0021] Among them, the high-temperature pipeline of the second heat exchanger is connected between the second temperature sensor and the second circulating water pump, and is used for heat exchange between the cold storage system and the refrigeration system.

[0022] Preferably, the water storage tank and the pipelines at both ends thereof are provided with a heat insulation layer, and the volume of the water storage tank depends on the duration required for the peak heat dissipation capacity of the fuel cell.

[0023] Preferably, a bypass parallel to the low-temperature pipeline of the first heat exchanger and connected to the second three-way valve and the water storage tank is provided. When the heat dissipation capacity of the fuel cell main cooling system is insufficient, the first three-way valve controls an appropriate flow of coolant to flow through the high-temperature pipeline of the first heat exchanger, and the second three-way valve controls an appropriate flow of chilled water to flow through the low-temperature pipeline of the first heat exchanger; when the heat dissipation capacity of the fuel cell main cooling system is sufficient, the first three-way valve controls all the coolant to flow through the radiator, and the second three-way valve allows all the chilled water to pass through the bypass parallel to the low-temperature pipeline of the first heat exchanger.

[0024] Preferably, a PID closed-loop control is set between the first three-way valve, the second three-way valve and the first temperature sensor. The flow rate of the coolant passing through the high-temperature pipeline of the first heat exchanger is adjusted by the first three-way valve, the flow rate of the chilled water passing through the low-temperature pipeline of the first heat exchanger is adjusted by the second three-way valve, and the measured value of the first temperature sensor is monitored to make it reach the required value.

[0025] Preferably, the refrigeration system includes the following components connected by pipelines:

[0026] A compressor, arranged downstream of the low-temperature pipeline of the second heat exchanger, compressing the flowing refrigerant to raise its temperature and providing the circulating power of the refrigerant in the pipeline;

[0027] A condenser, arranged downstream of the compressor, where the refrigerant exchanges heat with the environment to cool down;

[0028] A throttle valve, arranged between the condenser and the low-temperature pipeline of the second heat exchanger, reducing the pressure of the passing refrigerant.

[0029] Preferably, the fuel cell thermal management system with a chilled water storage function includes three working stages:

[0030] Idle working stage: Turn on the second circulating water pump of the refrigeration system and the chilled water storage system; control all the coolant to flow through the radiator through the first three-way valve; control all the chilled water to flow through the bypass parallel to the first heat exchanger through the second three-way valve;

[0031] Normal working stage: Control all the coolant to flow through the radiator through the first three-way valve; monitor the temperature of the second temperature sensor at the outlet of the water storage tank. When it is higher than the first threshold temperature, turn on the second circulating water pump to make the chilled water circulate, and at the same time turn on the refrigeration system to cool the chilled water in the chilled water storage system. Among them, control all the chilled water to flow through the bypass parallel to the low-temperature pipeline of the first heat exchanger through the second three-way valve; when the measured temperature of the second temperature sensor is lower than the second threshold temperature, turn off the refrigeration system and at the same time turn off the second circulating water pump to store a sufficient amount of chilled water in the water storage tank;

[0032] Overheat load working stage: Shut down the refrigeration system; Turn on the second circulation water pump to make the chilled water circulate; Control an appropriate amount of coolant to flow through the high-temperature pipeline of the first heat exchanger through the first three-way valve; Control an appropriate amount of chilled water to flow through the low-temperature pipeline of the first heat exchanger through the second three-way valve, so that the chilled water exchanges heat with the coolant to cool it down.

[0033] Preferably, the first threshold temperature and the second threshold temperature are set according to the heat dissipation requirement, and the first threshold temperature is higher than the second threshold temperature.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] The present invention adds a chilled water storage system as a buffer in the fuel cell system, effectively increasing the peak heat dissipation capacity of the existing heat dissipation system of the fuel cell and improving the power performance of the fuel cell vehicle.

[0036] The present invention provides an effective idle zero-output solution for the fuel cell system; If the fuel cell system cannot achieve zero power output during idling, the excess electric energy needs to be stored in the vehicle power battery; However, electric energy cannot be charged when the state of charge (SOC) of the power battery is high or at low temperature. At this time, the fuel cell system can only be shut down and restarted when there is a power demand for the vehicle. Obviously, this will increase the start-stop frequency of the system; In order to achieve zero output during idling, the usual method is to consume the excess electric power through an air compressor, a heater or a cooling fan, which is undoubtedly a waste; The present invention can use the refrigeration system to consume the excess electric energy during system idling and store it in the form of chilled water.

[0037] The present invention can reduce the failure rate and the frequency of operating condition changes of the fuel cell system, and improve the reliability and durability of the fuel cell system; Since the present invention can greatly increase the heat dissipation capacity of the fuel cell system, it effectively alleviates the over-temperature problem under the short-time peak power working condition and significantly reduces the occurrence of over-temperature failures. Brief Description of the Drawings

[0038] Figure 1 is the heat exchange relationship diagram of the fuel cell thermal management system of the present invention;

[0039] Figure 2 is the structural schematic diagram of a fuel cell thermal management system with a chilled water storage function of the present invention. Detailed Embodiments

[0040] The following will combine the drawings in the embodiments of the present invention to detail the technical solutions, structural features, achieved purposes and effects in the embodiments of the present invention.

[0041] It should be noted that the attached drawings are in a very simplified form and use non-precise scales. They are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention, rather than to limit the limiting conditions for the implementation of the present invention. Therefore, they do not have any technical substance. Any modification of the structure, change in the proportional relationship, or adjustment of the size, without affecting the efficacy that the present invention can produce and the purpose that can be achieved, should still fall within the scope covered by the technical content disclosed in the present invention.

[0042] It should be noted that in the present invention, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements clearly listed, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0043] This embodiment discloses a fuel cell thermal management system with a cold storage function, as Figure 1 and Figure 2 shown, including a fuel cell main cooling system, a cold storage system that exchanges heat with the fuel cell main cooling system through a first heat exchanger 6, and a refrigeration system that exchanges heat with the cold storage system through a second heat exchanger 11.

[0044] The first heat exchanger 6 is used for heat exchange between the fuel cell main cooling system and the cold storage system, and includes a high-temperature pipeline and a low-temperature pipeline. The high-temperature pipeline 61 of the first heat exchanger is connected in the fuel cell main cooling system, and the low-temperature pipeline 62 of the first heat exchanger is connected in the cold storage system. The second heat exchanger 11 is used for heat exchange between the cold storage system and the refrigeration system, and also includes a high-temperature pipeline and a low-temperature pipeline. The high-temperature pipeline 111 of the second heat exchanger is connected in the cold storage system, and the low-temperature pipeline 112 of the second heat exchanger is connected in the refrigeration system. Preferably, both the first heat exchanger 6 and the second heat exchanger 11 can be selected as stainless steel plate heat exchangers.

[0045] The fuel cell generates electricity through the electrochemical reaction between the fuel and air in the fuel cell stack 3 and simultaneously generates a large amount of heat. The fuel cell main cooling system directly dissipates heat from the fuel cell stack 3 by circulating coolant in the pipeline.

[0046] The main fuel cell cooling system includes the following components connected by pipelines: a first circulation water pump 1 disposed upstream of the fuel cell stack 3, which provides the circulation power for the coolant in the main fuel cell cooling system. In other embodiments, the first circulation water pump 1 can also be disposed at other positions in the pipeline of the main fuel cell cooling system and can also play the role of providing circulation power; a first temperature sensor 2 disposed upstream of the fuel cell stack 3, which is used to detect the temperature of the coolant entering the pipeline of the fuel cell stack 3; a radiator 5, which is connected in parallel with the high-temperature pipeline 61 of the first heat exchanger, and both the radiator 5 and the high-temperature pipeline 61 of the first heat exchanger are disposed downstream of the fuel cell stack 3. The coolant enters the radiator 5 and the high-temperature pipeline 61 of the first heat exchanger for heat dissipation after passing through the fuel cell stack 3; a first three-way valve 4 disposed between the radiator 5 and the high-temperature pipeline 61 of the first heat exchanger and the fuel cell stack 3, which is used to distribute the coolant flow passing through the radiator 5 and the high-temperature pipeline 61 of the first heat exchanger.

[0047] Among them, the radiator 5 is used to dissipate the heat in the coolant passing through the radiator 5 into the ambient air, thereby dissipating the heat of the main fuel cell cooling system into the ambient air.

[0048] The flow direction of the coolant in the main fuel cell cooling system is as follows: after being powered by the first circulation water pump 1, it enters the fuel cell stack 3 to take away its heat. After being distributed by the first three-way valve 4, part of the coolant is cooled by passing through the radiator 5, and the other part of the coolant exchanges heat with the cold storage system through the first heat exchanger 6 to be cooled. After the two parts of the coolant are cooled respectively, they both return to the stack circulation water pump 1. Among them, the first temperature sensor 2 monitors whether the temperature of the coolant entering the fuel cell stack 3 meets the requirements.

[0049] The chilled water circulates in the cold storage system and exchanges heat with the coolant of the main fuel cell cooling system through the first heat exchanger 6. The cold storage system includes the following components connected by pipelines: a second circulation water pump 7 disposed upstream of the low-temperature pipeline 62 of the first heat exchanger 6, which provides the circulation power for the chilled water in the cold storage system; a second three-way valve 8 disposed between the low-temperature pipeline 62 of the first heat exchanger and the second circulation water pump 7, which is used to control the flow rate of the chilled water flowing into the low-temperature pipeline 62 of the first heat exchanger; a water storage tank 9 disposed downstream of the low-temperature pipeline 62 of the first heat exchanger, which is used to store low-temperature chilled water; a second temperature sensor 10 disposed at the outlet of the water storage tank 9, which is used to detect the temperature of the chilled water in the cold storage system; a high-temperature pipeline 111 of the second heat exchanger connected between the second temperature sensor 10 and the second circulation water pump 7, which is used for heat exchange between the cold storage system and the refrigeration system.

[0050] Among them, the water storage tank 9 and the pipelines at both ends thereof are provided with heat insulation layers, and the volume of the water storage tank 9 depends on the duration required for the peak heat dissipation capacity of the fuel cell.

[0051] By setting a bypass in parallel with the low-temperature pipeline 62 of the first heat exchanger, that is, a bypass that directly connects between the second three-way valve 8 and the water storage tank 9 while avoiding the low-temperature pipeline 62 of the first heat exchanger; the second three-way valve 8 controls the flow rate of the chilled water flowing into the low-temperature pipeline 62 of the first heat exchanger. Specifically, when the heat dissipation capacity of the fuel cell main cooling system is insufficient, that is, when not all of the coolant can be reduced to the required temperature only by the radiator 5, the first three-way valve 4 controls an appropriate flow rate of the coolant to flow through the high-temperature pipeline 61 of the first heat exchanger, and the second three-way valve 8 also controls an appropriate flow rate of the chilled water to flow through the low-temperature pipeline 62 of the first heat exchanger and then to the water storage tank 9, so as to be able to share part of the heat dissipation capacity of the fuel cell main cooling system. The other chilled water directly flows through the bypass in parallel with the low-temperature pipeline 62 of the first heat exchanger to the water storage tank 9; when the heat dissipation capacity of the fuel cell main cooling system is sufficient, the first three-way valve 4 controls all of the coolant to flow through the radiator 5 for heat dissipation, and the second three-way valve 8 controls all of the chilled water to pass through the bypass in parallel with the low-temperature pipeline 62 of the first heat exchanger and be stored in the water storage tank 9.

[0052] To make the heat dissipation effect of the chilled water on the coolant reach the expectation, a PID (Proportional Integral Derivative) closed-loop control is set between the first three-way valve 4, the second three-way valve 8 and the first temperature sensor 2. By adjusting the flow rate of the coolant passing through the high-temperature pipeline 61 of the first heat exchanger and the flow rate of the coolant passing through the radiator 5 through the first three-way valve 4, and adjusting the flow rate of the chilled water passing through the low-temperature pipeline 62 of the first heat exchanger through the second three-way valve 8, and at the same time monitoring the measured value of the first temperature sensor 2, that is, the water temperature entering the fuel cell stack 3, to make it reach the allowable value. Generally, the maximum allowable water temperature entering the stack is 70 °C. Among them, the flow rate of the coolant passing through the radiator 5 is controlled within a certain range so that the heat dissipation capacity of the radiator 5 can be exerted and within the maximum heat dissipation capacity of the radiator 5.

[0053] The flow direction of the chilled water in the cold storage system is: after the chilled water is powered by the second circulation pump 7, it exchanges heat with the fuel cell main cooling system through the first heat exchanger 6 or directly flows to the water storage tank 9, then flows through the second heat exchanger 11 to exchange heat with the refrigeration system and then returns to the second circulation pump 7.

[0054] The refrigerant circulates within the refrigeration system and exchanges heat with the chilled water in the chilled water storage system through the second heat exchanger 11. The refrigeration system includes the following components connected by pipelines: a compressor 13 disposed downstream of the low-temperature pipeline 112 of the second heat exchanger, which compresses the flowing refrigerant to raise its temperature and provides the circulating power of the refrigerant in the pipeline; a condenser 14 disposed downstream of the compressor 13, where the refrigerant exchanges heat with the environment to cool down; a throttle valve 12 disposed between the condenser 14 and the low-temperature pipeline of the second heat exchanger 11, which reduces the pressure of the flowing refrigerant. At the same time, part of the refrigerant may vaporize, further reducing the temperature of the refrigerant flowing out of the throttle valve; the cooled refrigerant flows through the second heat exchanger 11 to exchange heat with the chilled water storage system and then flows into the compressor 13 for recycling.

[0055] Using the above fuel cell thermal management system to dissipate heat from the fuel cell, the operation of the chilled water storage system and the refrigeration system is controlled during different working stages, enabling it to store chilled water at low temperature when the main cooling system of the fuel cell dissipates enough heat and assisting in heat dissipation when the main cooling system of the fuel cell dissipates insufficient heat. Specifically, it includes the following three working stages:

[0056] Idle working stage: At this time, the required power of the whole vehicle is zero. If the fuel cell system is directly shut down, it will cause the fuel cell system to start and stop frequently, thereby reducing its service life. Therefore, the fuel cell system usually operates at a reduced power; reducing the power can improve the energy conversion efficiency of the fuel cell, but at the same time, the single-cell voltage will also increase, and too high a single-cell voltage will also shorten its service life; therefore, the fuel cell system usually specifies a minimum power operating condition to keep both the single-cell voltage and the power at appropriate levels. However, the normal auxiliary power consumption under this minimum power operating condition is often not sufficient to consume all the power generated by the fuel cell stack 3.

[0057] Therefore, during the idle working stage, there is no need for the chilled water storage system to exchange heat with the main cooling system of the fuel cell. The second circulation water pump 7 and the compressor 13 of the refrigeration system and the chilled water storage system are turned on to consume the excess output power of the fuel cell system under the minimum power operating condition. At this time: the coolant is controlled by the first three-way valve 4 to flow entirely through the radiator 5; the refrigerant circulates within the refrigeration system to consume the excess power; after the chilled water exchanges heat with the refrigerant through the second heat exchanger 11 and cools down, it is controlled by the second three-way valve 8 to flow entirely through the bypass parallel to the first heat exchanger 6 and circulate within the chilled water storage system to consume the excess power. At the same time, the storage of chilled water at low temperature is carried out in the water storage tank 9. However, generally, the excess power during the idle working stage cannot complete the storage of a sufficient amount of chilled water at low temperature, and it is still necessary to store chilled water at low temperature in the next stage.

[0058] Normal operation stage: At this time, the vehicle's required power is medium or the ambient temperature is low, making the heat dissipation capacity of the radiator 5 sufficient. Its cooling fan is not fully open, and there is no need for the cold storage system to assist in heat dissipation. The storage of low-temperature chilled water can be carried out. Specifically: control all the coolant to flow through the radiator 5 through the first three-way valve 4; monitor the temperature of the second temperature sensor 10 at the outlet of the water storage tank 9. When its temperature is higher than the first threshold temperature, turn on the second circulation pump 7 to make the chilled water circulate, and at the same time turn on the compressor 13 of the refrigeration system to cool the chilled water in the cold storage system by the refrigeration system. Among them, control all the chilled water to flow through the bypass parallel to the low-temperature pipeline 62 of the first heat exchanger through the second three-way valve 8; when the measured temperature of the second temperature sensor 10 is lower than the second threshold temperature, turn off the refrigeration system and at the same time turn off the second circulation pump 7, and store a sufficient amount of chilled water in the water storage tank 9.

[0059] Among them, the first threshold temperature and the second threshold temperature are set according to the heat dissipation requirements, and the first threshold temperature is higher than the second threshold temperature. For example, the first threshold temperature is set to 25 °C and the second threshold temperature is set to 10 °C.

[0060] Overheating load operation stage: At this time, the vehicle's required power is high and the ambient temperature is also high, making it impossible to fully reduce the temperature of the main cooling system of the fuel cell stack even when the radiator 5 is operating at full load (the cooling fan is fully open). Therefore, it is necessary to turn on the cold storage system to assist in heat dissipation and cooling. Specifically: turn off the refrigeration system to prevent it from consuming additional power; turn on the second circulation pump 7 of the cold storage system to make the chilled water circulate; control an appropriate amount of coolant to flow through the high-temperature pipeline 61 of the first heat exchanger through the first three-way valve 4; control an appropriate amount of chilled water to flow through the low-temperature pipeline 62 of the first heat exchanger through the second three-way valve 8 to make the chilled water exchange heat and cool part of the coolant, thereby improving the peak heat dissipation capacity of the fuel cell.

[0061] In other embodiments, the air conditioning system or heat pump system on the vehicle can also be utilized or modified as the refrigeration system to provide a cold source for the cold storage system to cool the chilled water, further reducing costs and saving space.

[0062] The present invention adds a cold storage system as a buffer in the fuel cell system, effectively increasing the peak heat dissipation capacity of the existing heat dissipation system of the fuel cell and improving the power performance of the fuel cell vehicle.

[0063] For example, for a fuel cell vehicle with a rated power demand of 80 kW and a peak power demand of 120 kW, a radiator with a capacity of 80 kW can be selected, and a cold storage system with a 60 L water storage tank can be configured. When the vehicle is operating at peak power, the cold storage system can support the vehicle to operate at peak power (more than 50% over the rated load) for more than 6 minutes, which is sufficient to support the vehicle to travel at full speed for several kilometers. The detailed calculation is as follows: Assume that the target temperature (the second threshold temperature) of the cold storage water system is 10 °C, and the maximum allowable inlet temperature of the fuel cell system is 70 °C; then the peak power operation time t = Q / W = 15120 kJ / 40 kW = 378 s = 6.3 min, where Q is the heat capacity of the cold storage water, Q = C × m × ΔT = 4.2 kJ / kg / K × 60 kg × (70 - 10) K = 15120 kJ, and W is the auxiliary heat dissipation power provided by the cold storage system, W = 120 kW - 80 kW = 40 kW.

[0064] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be recognized that the above description should not be construed as a limitation of the present invention. After those skilled in the art have read the above content, various modifications and alternatives to the present invention will be obvious. Therefore, the protection scope of the present invention should be defined by the appended claims.

Claims

1. A fuel cell thermal management system with a cold storage function, characterized in that, Including: A main fuel cell cooling system, which includes a first three-way valve. The main fuel cell cooling system directly dissipates heat from the fuel cell stack through the circulation of coolant. A cold storage system, including a second three-way valve and a water storage tank. Chilled water circulates therein and exchanges heat with the coolant of the main fuel cell cooling system through a first heat exchanger. Among them, the first heat exchanger includes a high-temperature pipeline and a low-temperature pipeline. A refrigeration system, in which refrigerant circulates and exchanges heat with the chilled water in the cold storage system through a second heat exchanger. A bypass is provided in parallel with the low-temperature pipeline of the first heat exchanger and is respectively connected to the second three-way valve and the water storage tank. When the heat dissipation capacity of the main fuel cell cooling system is insufficient, the first three-way valve controls an appropriate flow of coolant to flow through the high-temperature pipeline of the first heat exchanger, and the second three-way valve controls an appropriate flow of chilled water to flow through the low-temperature pipeline of the first heat exchanger. When the heat dissipation capacity of the main fuel cell cooling system is sufficient, the first three-way valve controls all the coolant to flow through the radiator, and the second three-way valve allows all the chilled water to pass through the bypass in parallel with the low-temperature pipeline of the first heat exchanger.

2. The fuel cell thermal management system with a cold storage function according to claim 1, wherein The high-temperature pipeline of the first heat exchanger is connected in the main fuel cell cooling system, and the low-temperature pipeline of the first heat exchanger is connected in the cold storage system. The second heat exchanger also includes a high-temperature pipeline and a low-temperature pipeline. Among them, the high-temperature pipeline of the second heat exchanger is connected in the cold storage system, and the low-temperature pipeline of the second heat exchanger is connected in the refrigeration system.

3. The fuel cell thermal management system with a cold storage function as claimed in claim 2, characterized in that, The main fuel cell cooling system includes the following components connected by pipelines: A first circulation pump, which provides circulation power for the coolant in the main fuel cell cooling system. A first temperature sensor, which is arranged upstream of the fuel cell stack and detects the inlet stack water temperature of the coolant in the pipeline entering the fuel cell stack. A radiator, which is connected in parallel with the high-temperature pipeline of the first heat exchanger. Both the radiator and the first heat exchanger are arranged downstream of the fuel cell stack to dissipate heat from the coolant. The first three-way valve, which is arranged between the radiator, the first heat exchanger and the fuel cell stack, and controls and distributes the coolant flow through the radiator and the high-temperature pipeline of the first heat exchanger.

4. The fuel cell thermal management system with a cold storage function according to claim 3, characterized in that, The cold storage system includes the following components connected by pipelines: A second circulation pump, which is arranged upstream of the low-temperature pipeline of the first heat exchanger and provides circulation power for the chilled water in the cold storage system. The second three-way valve, which is arranged between the low-temperature pipeline of the first heat exchanger and the second circulation pump, and is used to control the chilled water flow into the low-temperature pipeline of the first heat exchanger. The water storage tank, which is arranged downstream of the low-temperature pipeline of the first heat exchanger and stores the chilled water when the chilled water circulation is not required. A second temperature sensor, which is arranged at the outlet of the water storage tank and is used to detect the chilled water temperature of the cold storage system. Among them, the high-temperature pipeline of the second heat exchanger is connected between the second temperature sensor and the second circulation pump, and is used for heat exchange between the cold storage system and the refrigeration system.

5. The fuel cell thermal management system with a cold storage function according to claim 4, characterized in that, The water storage tank and the pipelines at both ends thereof are provided with a heat insulation layer, and the volume of the water storage tank depends on the duration required for the peak heat dissipation capacity of the fuel cell.

6. The fuel cell thermal management system with a cold storage function according to claim 4, characterized in that PID closed-loop control is set between the first three-way valve, the second three-way valve and the first temperature sensor. The coolant flow rate through the high-temperature pipeline of the first heat exchanger is adjusted by the first three-way valve, the chilled water storage flow rate through the low-temperature pipeline of the first heat exchanger is adjusted by the second three-way valve, and the measured value of the first temperature sensor is monitored to reach the required value.

7. The fuel cell thermal management system with a cold storage function according to claim 6, characterized in that The refrigeration system includes the following connected by pipelines: A compressor, arranged downstream of the low-temperature pipeline of the second heat exchanger, compressing the flowing refrigerant to raise its temperature and providing the circulating power of the refrigerant in the pipeline; A condenser, arranged downstream of the compressor, where the refrigerant exchanges heat with the environment to cool down; A throttle valve, arranged between the condenser and the low-temperature pipeline of the second heat exchanger, reducing the pressure of the flowing refrigerant.

8. The fuel cell thermal management system with a cold storage function according to claim 7, characterized in that, It includes three working stages: Idle working stage: Turn on the second circulation water pump of the refrigeration system and the chilled water storage system; control all the coolant to flow through the radiator through the first three-way valve; control all the chilled water storage to flow through the bypass parallel to the first heat exchanger through the second three-way valve. Normal working stage: Control all the coolant to flow through the radiator through the first three-way valve; monitor the temperature of the second temperature sensor at the outlet of the water storage tank. When the temperature is higher than the first threshold temperature, turn on the second circulation water pump to make the chilled water storage circulate, and at the same time turn on the refrigeration system to cool the chilled water storage in the chilled water storage system. Among them, control all the chilled water storage to flow through the bypass parallel to the low-temperature pipeline of the first heat exchanger through the second three-way valve; when the measured temperature of the second temperature sensor is lower than the second threshold temperature, turn off the refrigeration system and at the same time turn off the second circulation water pump, and store a sufficient amount of chilled water storage in the water storage tank. Overheat load working stage: Turn off the refrigeration system; turn on the second circulation water pump to make the chilled water storage circulate; control an appropriate amount of coolant to flow through the high-temperature pipeline of the first heat exchanger through the first three-way valve; control an appropriate amount of chilled water storage to flow through the low-temperature pipeline of the first heat exchanger through the second three-way valve, so that the chilled water storage exchanges heat with the coolant to cool it down.

9. The fuel cell thermal management system with a cold storage function as claimed in claim 8, characterized in that, The first threshold temperature and the second threshold temperature are set according to the heat dissipation requirements, and the first threshold temperature is higher than the second threshold temperature.

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