Extended range fuel cell thermal management system and control method thereof, automobile

Abstract

The application belongs to the technical field of automobile thermal management, and provides a range extending fuel cell thermal management system, a control method thereof and an automobile. The system comprises a heating circulation loop, a refrigeration circulation loop, a stack circulation loop and a first heat exchanger. The stack circulation loop sequentially passes through a stack and the first heat exchanger, the refrigeration circulation loop sequentially passes through a refrigeration unit and the first heat exchanger, the heating circulation loop sequentially passes through a heater and the first heat exchanger, and heat exchange is performed among the stack circulation loop, the refrigeration circulation loop and the heating circulation loop in the first heat exchanger. When the stack is cold started, the heating circulation loop heats the stack through the first heat exchanger and the stack circulation loop, thereby improving the success probability of cold starting of the fuel cell. When the stack is normally operated, the stack circulation loop exchanges heat with the heating circulation loop through the first heat exchanger, and the heating circulation loop utilizes the heat of the stack, thereby improving the heat utilization rate of the fuel cell.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of automobile thermal management, in particular to a range-extended fuel cell thermal management system, a control method thereof and an automobile. BACKGROUND

[0002] Fuel cell vehicles have advantages of no pollution, zero emission, renewable resources consumed, etc. However, fuel cells usually have problems of cold start failure and low thermal utilization rate. When a fuel cell starts in a low temperature environment below 0℃, the water produced by the reaction will first freeze in the catalyst layer, causing the reaction active sites of the catalyst layer to be covered and the oxygen transmission to be blocked, resulting in a sudden drop in voltage. When the catalyst layer is completely covered with ice and the stack temperature has not risen above 0℃, the heat generated by the cold start failure will not be able to counteract the low temperature outside, resulting in a failure to start the fuel cell. On the other hand, the freezing process of the catalyst layer will cause a gap between the catalyst layer and the proton exchange membrane, and the freezing / thawing cycle will cause the collapse and densification of the micro-porous structure of the catalyst layer and the coarsening of the platinum particles in the catalyst layer, resulting in a decrease in the electrochemical active surface area and difficulty in recovery, thereby permanently damaging the power generation performance of the fuel cell, and the more the number of cycles, the lower the cold start temperature, the greater the damage to the battery, and the faster the fuel cell degradation rate.

[0003] In order to solve the problem of cold start failure of fuel cells, one of the current strategies is usually to use gas purging when the stack is shut down, but this will cause irreversible damage to the electrodes. Another strategy is to preheat the stack and its internal polar plates and membrane electrodes by means of on-board power battery electric heating or on-board hydrogen catalytic combustion heat release, so that the stack reaches the temperature requirement for starting. However, even with this method, cold start may be difficult or even fail, and it will also consume on-board hydrogen and power battery power. At the same time, during normal operation of the fuel cell, its temperature is relatively high, and it usually needs to be actively cooled. The heat generated is wasted, resulting in low thermal utilization rate of the fuel cell. SUMMARY

[0004] The purpose of the present application is to provide a range-extended fuel cell thermal management system, a control method thereof and an automobile, to solve the problems of cold start failure and low thermal utilization rate of fuel cells in the prior art.

[0005] Specifically, in order to achieve the above-mentioned purpose, the application provides a range-extended fuel cell thermal management system, comprising a heating circulation loop, a refrigeration circulation loop, a stack circulation loop and a first heat exchanger; the stack circulation loop is provided with a stack, the refrigeration circulation loop is provided with a refrigeration unit, the heating circulation loop is provided with a heater, the heating circulation loop, the refrigeration circulation loop and the stack circulation loop are connected through the first heat exchanger, and heat exchange is performed between the heating circulation loop, the refrigeration circulation loop and the stack circulation loop in the first heat exchanger.

[0006] Optionally, the system further comprises a battery circulation loop and a second heat exchanger, the battery circulation loop sequentially passes through a battery and the second heat exchanger, the refrigeration circulation loop passes through the second heat exchanger, the second heat exchanger is connected in parallel with the first heat exchanger in the refrigeration circulation loop, the heating circulation loop passes through the second heat exchanger, the second heat exchanger is connected in parallel with the first heat exchanger in the heating circulation loop, and heat exchange is performed between the heating circulation loop, the refrigeration circulation loop and the battery circulation loop in the second heat exchanger.

[0007] Optionally, the stack circulation loop is provided with a first liquid pump, the first liquid pump drives a heat exchange medium in the stack circulation loop to circulate in the stack circulation loop, the heating circulation loop is provided with a second liquid pump, the second liquid pump drives a heat exchange medium in the heating circulation loop to circulate in the heating circulation loop, and the battery circulation loop is provided with a third liquid pump, the third liquid pump drives a heat exchange medium in the battery circulation loop to circulate in the battery circulation loop.

[0008] Optionally, the stack circulation loop further comprises a stack radiator, and the stack radiator is connected in parallel with the first heat exchanger.

[0009] Optionally, the stack circulation loop further comprises a deionizer, and the deionizer is connected in parallel with the stack radiator, or the deionizer is connected in parallel with the stack, or the deionizer, the stack and the stack radiator are connected in parallel with each other.

[0010] Optionally, the stack circulation loop further comprises an intercooler, and the intercooler is connected in parallel with the stack in the stack circulation loop.

[0011] Optionally, the refrigeration circulation loop further comprises an evaporator, and the evaporator is connected in parallel with the first heat exchanger.

[0012] Optionally, the heating circulation loop further comprises a warm air core, and the warm air core is connected in series with the first heat exchanger in the heating circulation loop.

[0013] The application further provides a control method of the range-extended fuel cell thermal management system, for the range-extended fuel cell thermal management system according to any one of the above, when the fuel cell is cold started, the heating cycle loop heats the stack through the first heat exchanger and the stack cycle loop, when the temperature of the fuel cell exceeds a preset calibration value, the refrigeration cycle loop absorbs heat of the stack through the first heat exchanger and the stack cycle loop.

[0014] The application further provides an automobile comprising the range-extended fuel cell thermal management system according to any one of the above.

[0015] The range-extended fuel cell thermal management system, the control method thereof and the automobile provided by the application have the advantages that the heating cycle loop and the stack cycle loop both pass through the first heat exchanger. The heating cycle loop can exchange heat with the stack cycle loop through the first heat exchanger. When the stack is cold started, the heating cycle loop heats the stack through the first heat exchanger and the stack cycle loop, thereby improving the success probability of the cold start of the fuel cell. When the stack is normally operated, the stack cycle loop exchanges heat with the heating cycle loop through the first heat exchanger, and the heating cycle loop utilizes the heat of the stack, thereby improving the heat utilization rate of the fuel cell. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 Fig. 1 is a structural block diagram of the range-extended fuel cell thermal management system in the embodiment of the application;

[0017] Figure 2 Fig. 2 is a flowchart of the range-extended fuel cell thermal management system in the shutdown mode in the embodiment of the application;

[0018] Figure 3 Fig. 3 is a structural block diagram of the range-extended fuel cell thermal management system in the shutdown mode in the embodiment of the application;

[0019] Figure 4 Fig. 4 is a flowchart of the control method of the range-extended fuel cell thermal management system in the cold start mode in the embodiment of the application;

[0020] Figure 5 Fig. 5 is a structural block diagram of the control method of the range-extended fuel cell thermal management system in the cold start mode in the embodiment of the application;

[0021] Figure 6 Fig. 6 is a flowchart of the range-extended fuel cell thermal management system in the normal operation mode in the embodiment of the application.

[0022] Figure 7 Fig. 7 is a structural block diagram of the control method of the range-extended fuel cell thermal management system in the normal operation mode in the embodiment of the application;

[0023] Explanation of reference numerals: electric pile 1, four-way valve 2, electric pile radiator 3, first liquid pump 4, first water storage bottle 5, deionizer 6, intercooler 7, filter 8, first plate heat exchanger 10, PTC 11, heater core 12, second liquid pump 13, second water storage bottle 14, three-way valve 15, second plate heat exchanger 20, power battery 21, third liquid pump 22, evaporator 31, compressor 32, condenser 33, first expansion valve 34, second expansion valve 35, third expansion valve 36, first temperature sensor 37, second temperature sensor 38, third temperature sensor 39, temperature and pressure sensor 40. DETAILED DESCRIPTION

[0024] Other advantages and effects of the present application can be easily understood by those skilled in the art from the contents disclosed in the present specification. The present application can also be implemented or applied in other different embodiments, and the details in the present specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present application. It should be understood that the preferred embodiments are only for illustrating the present application, but not for limiting the protection scope of the present application.

[0025] Reference is made to Figures 1 to 6 It should be noted that the drawings provided in the present embodiments only schematically illustrate the basic concept of the present application, and thus the drawings only show the components related to the present application, but are not drawn according to the number, shape and size of the components in actual implementation. The shape, number and proportion of the components in actual implementation can be arbitrarily changed, and the layout pattern of the components can be more complicated. The structure, proportion, size, etc. shown in the drawings attached to the present specification are only used to understand and read the contents disclosed in the present specification, and do not limit the conditions for implementing the present application, and thus do not have technical significance. Any modification of the structure, change of the proportional relationship or adjustment of the size, without affecting the effects and purposes that can be achieved by the present application, should still fall within the scope of the technical contents disclosed in the present application. Meanwhile, the terms such as "upper", "lower", "left", "right", "middle" and "one" in the present specification are only for the convenience of understanding and reading, but not for limiting the scope of the present application, and the change or adjustment of the relative relationship, without substantially changing the technical contents, should also be considered as the scope of the present application.

[0026] Reference is made to Figure 1The embodiment provides a range-extending fuel cell thermal management system, which comprises a heating circulation loop, a refrigeration circulation loop, a stack circulation loop and a first heat exchanger. The stack circulation loop is provided with a stack 1, the refrigeration circulation loop is provided with a refrigeration unit, and the heating circulation loop is provided with a heater. The heating circulation loop, the refrigeration circulation loop and the stack circulation loop are connected through the first heat exchanger, and heat exchange is performed among the heating circulation loop, the refrigeration circulation loop and the stack circulation loop in the first heat exchanger.

[0027] In some embodiments, the range-extending fuel cell thermal management system further comprises a battery circulation loop and a second heat exchanger, the battery circulation loop sequentially passes through a battery and the second heat exchanger, the refrigeration circulation loop passes through the second heat exchanger, in the refrigeration circulation loop, the second heat exchanger is connected in parallel with the first heat exchanger, the heating circulation loop passes through the second heat exchanger, in the heating circulation loop, the second heat exchanger is connected in parallel with the first heat exchanger, and heat exchange is performed among the heating circulation loop, the refrigeration circulation loop and the battery circulation loop in the second heat exchanger.

[0028] Specifically, the stack circulation loop is provided with a first liquid pump 4, the first liquid pump 4 drives a heat exchange medium in the stack circulation loop to circulate in the stack circulation loop, the heating circulation loop is provided with a second liquid pump 13, the second liquid pump 13 drives a heat exchange medium in the heating circulation loop to circulate in the heating circulation loop, and the battery circulation loop is provided with a third liquid pump 22, the third liquid pump 22 drives a heat exchange medium in the battery circulation loop to circulate in the battery circulation loop.

[0029] In some embodiments, the stack circulation loop further comprises a stack radiator 3, and the stack radiator 3 is connected in parallel with the first heat exchanger. When the stack 1 normally operates and the temperature rises and needs to be radiated, the stack circulation loop can radiate the stack 1 through the stack radiator 3. The stack radiator 3 is correspondingly provided with a radiator fan, and the radiator fan is used to help the stack radiator 3 to radiate. In the embodiment, a condenser 33 in the refrigeration circulation loop is also arranged in the air flow direction of the radiator fan and located behind the stack radiator 3, so as to avoid affecting the heat dissipation of the stack 1.

[0030] Specifically, the stack circulation loop further comprises a deionizer 6, the deionizer 6 can be connected in parallel with the stack radiator 3 or the stack 1, and the deionizer 6, the stack radiator 3 and the stack 1 can also be connected in parallel with each other.

[0031] In some embodiments, the stack circulation loop further comprises an intercooler 7, and the intercooler 7 is connected in parallel with the stack 1 in the stack circulation loop.

[0032] In some embodiments, the refrigeration unit in the refrigeration cycle loop is a refrigeration semiconductor. In this embodiment, the refrigeration unit in the refrigeration cycle loop is a refrigeration cycle including an evaporator 31, a compressor 32, and a condenser 33. The compressed refrigerant in the compressor 32 is cooled and condensed after flowing into the condenser 33, and then enters the evaporator 31. The refrigerant evaporates and absorbs heat in the evaporator 31 to achieve the purpose of refrigeration. The refrigerant after absorbing heat flows into the compressor 32 for compression, completing the refrigeration cycle. The evaporator 31, the compressor 32, and the condenser 33 have high refrigeration efficiency and can meet the demand for refrigeration in the vehicle.

[0033] In some embodiments, in the refrigeration cycle loop, the electric compressor 32, the condenser 33, and the evaporator 31 are connected in series, and the first plate heat exchanger 10 and the second plate heat exchanger 20 are connected in parallel with the evaporator 31.

[0034] The condensed refrigerant in the condenser 33 can enter the first plate heat exchanger 10 to evaporate and refrigerate, so that the refrigeration cycle loop can exchange heat with the stack 1 through the first plate heat exchanger 10 to assist in refrigerating the stack 1. At the same time, the condensed refrigerant in the condenser 33 can enter the second plate heat exchanger 20 to evaporate and refrigerate, so that the refrigeration cycle loop can exchange heat with the power battery 21 through the second plate heat exchanger 20 to assist in refrigerating the power battery 21.

[0035] The heating cycle loop is also provided with a warm air core 12, and the warm air core 12 is connected in series with the first heat exchanger in the heating cycle loop. When the vehicle passenger compartment needs to be refrigerated, the evaporator 31 can be used to absorb heat and cool the passenger compartment, and when the passenger compartment needs to be heated, the warm air core 12 can be used to heat the passenger compartment. In the heating cycle loop, a second water bottle 14 is also provided for storing the coolant in the heating cycle loop.

[0036] The large circulation loop comprises the first liquid pump 4, the stack radiator 3, the four-way valve 2, the filter 8 and the stack 1 arranged in sequence. The small circulation loop comprises the first liquid pump 4, the plate heat exchanger, the stack 1, the four-way valve 2, the filter 8, the stack 1 arranged in sequence. The large circulation loop and the small circulation loop are connected in parallel through two flow-controllable outlets of the four-way valve 2. The deionizer 6 circuit comprises the deionizer 6 and the first water storage bottle 5. In the deionizer 6 circuit, the heat exchange medium flows into the first water storage bottle 5 from the outlet of the stack radiator 3 or the inlet of the stack 1, then flows into the deionizer 6, and then flows into the large and small circulation loops through the first liquid pump 4. Since the flow of the first water storage bottle 5 is small, and one of the inlets of the deionizer 6 is after the stack radiator 3, the pressure of the heat exchange medium flowing into the deionizer 6 is small, and the temperature is low, which further improves the working conditions of the deionizer 6 and prolongs the service life of the deionizer 6. Preferably, a temperature and pressure sensor 40 is installed at the inlet of the filter 8. The temperature and pressure sensor 40 is used to detect the pressure of the cooling liquid of the fuel cell before entering the stack, and can also detect the temperature T4 of the cooling liquid of the fuel cell before entering the stack. A second temperature sensor 38 is installed at the outlet of the stack 1. The second temperature sensor 38 is used to detect the temperature of the cooling liquid at the outlet of the fuel cell, i.e. the temperature T2 of the cooling liquid at the outlet of the stack 1. The flow of the cooling liquid in the large circulation loop can be controlled according to the feedback of the temperatures T4 and T2.

[0037] The intercooler circuit is connected in parallel with the large circulation loop and the small circulation loop. The intercooler circuit comprises the intercooler 7 connected between the normally open outlet of the four-way valve 2 and the inlet end of the first liquid pump 4. The heat exchange medium flows into the intercooler 7 from the large circulation loop or the small circulation loop through the four-way valve 2, and then is driven by the first liquid pump 4 to flow back to the large circulation loop or the small circulation loop.

[0038] Specifically, the four-way valve 2 in the embodiment comprises four open ends in communication with each other, including two normally open outlet ends and two adjustable inlet ends. The two outlet ends and the two inlet ends are in communication with each other. Specifically, the two adjustable inlet ends are ball valve structures with proportional flow control. The two normally open outlet ends are in communication with the intercooler 7 and the stack 1, respectively. The two adjustable inlet ends are in communication with the stack radiator 3 and the first plate heat exchanger 10, respectively.

[0039] In this embodiment, the heater is a PTC 11 (Positive Temperature Coefficient). When starting, the PTC 11 of the heating circuit can be used to assist heating, so that the temperature of the fuel cell can reach the required temperature more quickly. At the same time, the PTC 11 of the heating circuit can also reduce the temperature difference inside the fuel cell, avoid cold start failure, and prolong the service life of the fuel cell. In addition, the filter 8 is installed before the inlet of the stack 1. Because the flow resistance of the stack radiator 3, the four-way valve 2, the filter 8 and other components in the heat cycle of the stack 1 is large, the pressure of the cooling liquid entering the stack 1 is reduced, which can prevent the problem of membrane electrode failure caused by excessive pressure difference between the cooling liquid and the hydrogen side or the oxygen side, and effectively ensure the normal operation of the heat exchange unit in the stack 1.

[0040] In this embodiment, the second liquid pump 13 in the heating cycle circuit is a small power water pump, and the second liquid pump 13, the PTC 11, the warm air core 12 and the first plate heat exchanger 10 are connected in series. A three-way valve 15 is arranged between the PTC 11 and the warm air core 12, and the PTC 11 communicates with the warm air core 12 and the second plate heat exchanger 20 through the three-way valve 15. The heat exchange medium flowing through the PTC 11 enters the three-way valve 15, and then flows through the second plate heat exchanger 20 through the three-way valve 15 and returns to the second liquid pump 13 to complete the circulation. The heat exchange medium flowing through the PTC 11 enters the three-way valve 15, and then flows through the warm air core 12 and the first plate heat exchanger 10 through the three-way valve 15 and returns to the second liquid pump 13 to complete the circulation. In this embodiment, a first temperature sensor 37 is arranged at the outlet of the first plate heat exchanger 10 in the heating cycle circuit, which is used to detect the temperature T1 of the heat exchange medium flowing through the first plate heat exchanger 10 in the heating cycle circuit. Because the stack cycle circuit also passes through the first plate heat exchanger 10, when the stack 1 is normally operated, the heating cycle circuit and the stack cycle circuit can exchange heat in the first plate heat exchanger 10 to utilize the waste heat of the stack 1 to heat the passenger compartment.

[0041] In the heating cycle loop, the first plate heat exchanger 10 and the heater core 12 are connected in series in the first branch, and the second plate heat exchanger 20 is located in the second branch. The first branch and the second branch are connected in parallel via a three-way valve. When the fuel cell stack 1 is operating normally, the heat exchange medium heated by the first plate heat exchanger 10 and the heat exchange medium in the second plate heat exchanger 20 both return to the second liquid pump 13 to merge. The merged heat exchange medium re-enters the second plate heat exchanger 20 and can exchange heat with the battery cycle loop through the second plate heat exchanger 20, thereby heating the power battery 21. In this embodiment, the third liquid pump 22 is a low-power water pump, and the battery cycle loop includes the third liquid pump 22, the power battery 21, and the second plate heat exchanger 202. In practice, the power battery 21 includes, but is not limited to, other necessary devices of the power battery 21 heat exchange unit. A third temperature sensor 39 is installed at the inlet of the third liquid pump 22. The third temperature sensor 39 is used to detect the temperature of the heat exchange medium entering the third liquid pump 22, that is, the temperature T3 of the heat exchange medium entering the power battery 21.

[0042] Specifically, in this embodiment, the first heat exchanger is a first plate heat exchanger 10, and the second heat exchanger is a second plate heat exchanger 20. The thermal cycle of the fuel cell stack 1 includes a large circulation loop, a small circulation loop, a deionizer 6 loop, an intercooler loop, a filter 8, and a first liquid pump 4. The first liquid pump 4 is a high-power heat exchange medium pump.

[0043] This embodiment also provides a control method for a range-extended fuel cell thermal management system, used in the above-mentioned range-extended fuel cell thermal management system. When the fuel cell is cold-started, the heating cycle loop heats the fuel cell stack 1 through the first heat exchanger and the fuel cell stack circulation loop. When the temperature of the fuel cell exceeds a preset calibration value, the cooling cycle loop absorbs heat from the fuel cell stack 1 through the first heat exchanger and the fuel cell stack circulation loop.

[0044] In practice, the thermal management system of a range-extended fuel cell includes three operating modes: shutdown mode, low-temperature cold start mode, and normal operation mode. The specific operating modes are as follows:

[0045] like Figure 2 and Figure 3 As shown, when the fuel cell is in shutdown mode, the first liquid pump 4 is off. If the passenger compartment requires heating, the PTC 11 and the second liquid pump 13 are turned on. In the heating cycle, the outlet of the three-way valve 15 connected to the second plate heat exchanger 20 is closed, and the outlet of the three-way valve 15 connected to the heater core 12 is opened, allowing the heat exchange medium to circulate in the heater core 12 and the first plate heat exchanger 10. At this time, all the heat in the heater core 12 comes from the PTC 11. If the passenger compartment requires cooling, the compressor 32 in the cooling cycle is turned on, and the heat enters the evaporator 31 for cooling after passing through the third expansion valve 36.

[0046] As shown in Figure 4 and Figure 5 In the low-temperature cold start mode, the temperature of the fuel cell needs to be quickly raised to the normal operating temperature. The four-way valve 2 is controlled by the FCU (Fuel-cell Control Unit, fuel cell system controller). The first liquid pump 4 in the stack circulation loop is opened, and the large circulation loop is closed. In the heating circulation loop, the second liquid pump 13 is opened, the PTC 11 is powered on, the outlet of the three-way valve 15 connected to the heater core 12 is opened, and the auxiliary stack 1 is heated. When the stack 1 is successfully started, the heated heat exchange medium in the heating circulation loop flows into the first plate heat exchanger 10 through the heater core 12, exchanges heat with the stack circulation loop, continues to heat the auxiliary stack 1, and flows into the second plate heat exchanger 20, exchanges heat with the battery circulation loop through the second plate heat exchanger 20, and heats the power battery 21, thereby shortening the cold start time.

[0047] A temperature and pressure sensor 40 is arranged in the stack circulation loop. The temperature and pressure sensor 40 collects the temperature of the cooling liquid at the inlet of the stack 1. If the inlet temperature of the stack is lower than the pre-set calibration value, the cooling liquid of the stack 1 needs to be heated more quickly. In the case where the difference between the air inlet pressure and the cooling liquid inlet pressure of the stack does not exceed the calibration value, and the rotation speed of the first liquid pump 4 does not exceed the calibration value, the rotation speed of the first liquid pump 4 is increased until the inlet temperature of the cooling liquid reaches the normal operating temperature range of the fuel cell, and the minimum single cell voltage of the fuel cell meets the requirements of the vehicle start-up, and the cold start is considered successful.

[0048] Specifically, after the VCU requests the power signal, the ambient temperature T0 is first detected. If the ambient temperature T0 is less than the pre-set calibration temperature, such as 0°C, the cold start mode is entered. Otherwise, the normal start is entered. In the cold start mode, the temperature of the fuel cell needs to be quickly raised to the normal operating temperature. The four-way valve 2 is controlled by the FCU. The small circulation loop is opened, the large circulation loop is closed, and the first liquid pump 4 is opened. Then the outlet of the three-way valve 15 connected to the heater core 12 is opened, the second liquid pump 13 is opened (90% occupancy ratio), the PTC 11 is powered on, the auxiliary stack 1 is heated, and the stack 1 is started.

[0049] The rotation speed n of the first liquid pump 4 is detected and compared with the pre-set target rotation speed n1. If the rotation speed n of the first liquid pump 4 is less than the calibration value n1, the air inlet pressure value and the cooling liquid inlet pressure difference value of the stack 1 are detected. If the air inlet pressure value and the cooling liquid inlet pressure difference value are both <0.7bar, the power of the first liquid pump 4 is continued to be increased, and the rotation speed n of the first liquid pump 4 is increased until the rotation speed n of the first liquid pump 4 is greater than or equal to the calibration value n1.

[0050] When the rotation speed n of the first liquid pump 4 is greater than or equal to the rated value n1, the temperature T4 of the heat exchange medium at the inlet of the fuel cell stack 1 is collected by the temperature pressure sensor 40, and T4 is compared with the normal working temperature value of the fuel cell stack 1, for example, 20°C. If T4 is less than or equal to 20°C, the time after the start of the fuel cell stack 1 is calculated. If the time after the start of the fuel cell stack 1 is less than or equal to the shutdown time value t1, the fuel cell stack 1 is continuously started. If the time after the start of the fuel cell stack 1 is greater than the shutdown time value t1, the fuel cell stack 1 is purged according to the low-temperature shutdown condition to protect the internal structure of the fuel cell stack 1 from being damaged. At the same time, a signal of cold start failure of the fuel cell stack 1 is output, and the start of the fuel cell stack 1 is ended.

[0051] If T4 is greater than the normal working temperature value, and the minimum single cell voltage meets the start requirement, the cold start is considered successful. The three-way valve 15 is opened to communicate with the outlet of the second plate heat exchanger 20. The waste heat of the fuel cell stack 1 is transferred to the heating circulation loop through the first plate heat exchanger 10, and the air conditioning core 12 to heat the passenger compartment. At the same time, the heat of the heating circulation loop is transferred to the battery circulation loop through the second plate heat exchanger 20 to assist the heating of the power battery 21 to shorten the cold start time. The temperature T3 of the heat exchange medium entering the third liquid pump 22 in the battery circulation loop is continuously obtained by the third temperature sensor 39 at the inlet of the third liquid pump 22, and T3 is compared with the normal working temperature value of the power battery 21, for example, 25°C. If T4 is greater than 25°C, the outlet of the three-way valve 15 communicating with the second plate heat exchanger 20 is closed, and the cold start is ended.

[0052] In some embodiments, before the cold start of the fuel cell stack 1 is successful, the temperature T2 of the heat exchange medium at the outlet of the fuel cell stack 1 can also be detected by the second temperature sensor 38. If the temperature difference of the heat exchange medium between T4 and T2 exceeds the preset temperature difference value, it indicates that the fuel cell cooling liquid needs to be warmed up more quickly. In the case that the difference between the air inlet pressure and the cooling liquid inlet pressure of the fuel cell stack 1 does not exceed the rated value, for example, 0.7 bar, the power of the first liquid pump 4 is increased to increase the rotation speed of the first liquid pump 4.

[0053] As Figure 6 and Figure 7If the ambient temperature T0 is greater than or equal to a preset calibration temperature, such as 0°C, the normal operation mode is entered. In the normal operation mode, the VCU (vehicle Control Unit) sends a request power signal to the FCU, and the FCU starts the stack 1 to enter the conventional cooling mode. The spool of the four-way valve 2 gradually rotates to the inlet connected to the large circulation loop, and the first liquid pump 4 is started. The speed of the first liquid pump 4 is controlled according to the outlet temperature, the inlet temperature and the inlet pressure of the cooling liquid. At the same time, the speed of the radiator fan and the rotation angle of the spool of the four-way valve 2 are controlled according to the inlet temperature. When the FCU receives an increase power signal, the outlet temperature, the inlet temperature and the calibration value are controlled. When the outlet temperature and the inlet temperature do not exceed the calibration value, the speed of the first liquid pump 4, the speed of the radiator fan and the rotation angle of the four-way valve 2 are continuously adjusted until the large circulation loop is completely opened and the small circulation loop is completely closed. With the further increase of the power of the stack 1, when the outlet temperature and the inlet temperature exceed the calibration value, the auxiliary cooling mode is entered. At this time, the first expansion valve 34 is opened, and it is judged whether the passenger compartment and the power battery 21 need to be cooled. If the passenger compartment needs to be cooled, the corresponding third expansion valve 36 is opened. If the power battery 21 needs to be cooled, the corresponding second expansion valve 35 is opened. Then the electric compressor 32 is started. The refrigeration circulation loop can cool the stack 1 through the first plate heat exchanger 10, and can cool the power battery 21 through the second plate heat exchanger 20, so as to solve the problem of insufficient heat dissipation of the stack radiator 3 under full power and the like working conditions, and is beneficial to improve the power generation of the stack 1.

[0054] During this period, the outlet of the three-way valve 15 connected to the second plate heat exchanger 20 in the heating circulation loop is closed, and the power battery 21 does not need to be heated. At the same time, if the passenger compartment needs to be heated, the outlet of the three-way valve 15 connected to the heater core 12 in the heating circulation loop is opened, and the second liquid pump 13 is started. During the heating process, the rotation angle of the spool of the four-way valve 2 can be adjusted to control the opening of the small circulation loop according to the temperature of the outlet of the first plate heat exchanger 10 in the heating circulation loop, so as to partially or even completely utilize the waste heat of the stack 1 to heat the passenger compartment, so as to reduce the power consumption of the PTC 11.

[0055] Specifically, in the normal operation mode, the VCU requests the power signal to start the stack to enter the small power cooling mode, the spool of the four-way valve 2 gradually rotates to the inlet connected to the large circulation loop, and the first liquid pump 4 is started. The speed n of the first liquid pump 4 is controlled according to the cooling liquid inlet stack temperature T4 and the cooling liquid inlet stack pressure detected by the temperature and pressure sensor 40 and the cooling liquid outlet stack temperature T2 detected by the second temperature sensor 38. At the same time, the speed of the radiator fan and the rotation angle of the spool of the four-way valve 2 are controlled according to the temperature T4. When the increase power signal is received, the temperature T4 is compared with the preset inlet stack temperature calibration value, and when the temperature T4 does not exceed the inlet stack temperature calibration value, the speed of the first liquid pump 4, the speed of the fan of the stack radiator 3, and the rotation angle of the spool of the four-way valve 2 are continuously adjusted until the large circulation loop is completely opened and the small circulation loop is closed. With the further increase of the power of the first liquid pump 4, when the inlet stack temperature T4 exceeds the inlet stack temperature calibration value, the auxiliary cooling mode is entered. The first expansion valve 34 is opened, and it is judged whether the passenger compartment needs to be cooled and whether the power battery needs to be cooled. If the passenger compartment needs to be cooled, the third expansion valve 36 is opened, and if the temperature of the cooling liquid at the inlet of the power battery, i.e., T3> 25℃, the second expansion valve 35 is opened. Then the compressor 32 is started to perform refrigeration. And the heat is exchanged through the first plate heat exchanger 10 to cool the stack 1 and the power battery 21, solving the problem that the heat dissipation of the stack 1 still cannot meet the requirements under the full power working condition of the stack radiator 3, and having a positive effect on inhibiting the ion precipitation of the stack radiator 3.

[0056] During this period, the three-way valve 15 is connected to the outlet of the second plate heat exchanger 20 and is closed, and the power battery 21 does not need to be heated. At the same time, if the passenger compartment needs to be heated, the rotation angle of the spool of the four-way valve 2 is adjusted, the three-way valve 15 is connected to the outlet of the heater core 12 and is opened, and the second liquid pump 13 is started. The temperature T1 at the outlet of the first plate heat exchanger 10 in the heating circulation loop can be used for judgment. If the temperature T1 is greater than the preset heating temperature, such as 70℃, the PTC 11 is closed, and if the temperature T1 is less than or equal to 70℃, the PTC 11 is opened. The heating of the passenger compartment by the waste heat of the stack 1 is realized by controlling the opening degree of the small circulation loop, so as to reduce the power consumption of the PTC.

[0057] The embodiment also provides an automobile comprising the range-extended fuel cell thermal management system as described above.

[0058] The range-extending fuel cell thermal management system, the control method thereof and the automobile of the embodiment can heat the electric pile 1 through the first heat exchanger and the electric pile circulation loop when the electric pile 1 is cold started, thereby improving the success probability of the cold start of the fuel cell. When the electric pile 1 is normally operated, the electric pile circulation loop exchanges heat with the heating circulation loop through the first heat exchanger, and the heat of the electric pile 1 is utilized through the heating circulation loop, thereby improving the heat utilization rate of the fuel cell. Meanwhile, the filter 8 and the four-way valve 2 are arranged before the inlet of the electric pile 1, so that the pressure of the cooling liquid at the inlet of the electric pile 1 can be greatly reduced, thereby avoiding the problem that the graphite plate of the electric pile 1 is damaged due to excessive pressure, and increasing the service life of the electric pile 1. The electric pile heat exchange unit is separated from the passenger cabin heat exchange unit, so that the influence of the passenger cabin heating loop on the electric conductivity of the fuel cell system can be avoided, and the service life of the deionizer 6 is increased. The embodiment can fully utilize the PTC 11 to assist the electric pile 1 and the power battery 21 to be heated when cold started, and can utilize part or even all of the waste heat of the electric pile 1 to heat the passenger cabin heating system when the fuel cell is driven to travel. When the temperature difference between the inlet and outlet of the electric pile radiator 3 is still too high under the full load working condition of the electric pile, the electric pile 1 can be cooled by the passenger cabin refrigeration loop, so that the phenomenon that the power of the electric pile 1 is reduced due to overheating can be reduced, the power generation power of the vehicle is improved, the working efficiency of the fuel cell thermal management system is improved, the electric pile 1 can be quickly cold started, and the heat utilization rate of the electric pile 1 is improved.

[0059] The above embodiments only illustrate the principles and effects of the present application, and are not used to limit the present application. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical thought of the present application should be covered by the claims of the present application.

Claims

1. A range-extended fuel cell thermal management system, characterized in that, It includes a heating cycle loop, a cooling cycle loop, an electric stack cycle loop, and a first heat exchanger; the electric stack cycle loop is equipped with an electric stack, the cooling cycle loop is equipped with a cooling unit, and the heating cycle loop is equipped with a heater. The heating cycle loop, the cooling cycle loop, and the electric stack cycle loop are respectively connected through the first heat exchanger, and heat exchange occurs between the heating cycle loop, the cooling cycle loop, and the electric stack cycle loop in the first heat exchanger. It also includes a battery circulation loop and a second heat exchanger. The battery circulation loop passes through the battery and the second heat exchanger in sequence. The refrigeration circulation loop passes through the second heat exchanger. In the refrigeration circulation loop, the second heat exchanger is connected in parallel with the first heat exchanger. The heating circulation loop passes through the second heat exchanger. In the heating circulation loop, the second heat exchanger is connected in parallel with the first heat exchanger. The heating circulation loop, the refrigeration circulation loop, and the battery circulation loop exchange heat with each other in the second heat exchanger.

2. The range-extended fuel cell thermal management system according to claim 1, characterized in that: The fuel cell circulation loop is equipped with a first liquid pump, which drives the heat exchange medium in the fuel cell circulation loop to circulate in the fuel cell circulation loop. The heating circulation loop is equipped with a second liquid pump, which drives the heat exchange medium in the heating circulation loop to circulate in the heating circulation loop. The battery circulation loop is equipped with a third liquid pump, which drives the heat exchange medium in the battery circulation loop to circulate in the battery circulation loop.

3. The range-extended fuel cell thermal management system according to claim 1, characterized in that: The fuel cell stack circulation loop also includes a fuel cell stack radiator, which is connected in parallel with the first heat exchanger.

4. The range-extended fuel cell thermal management system according to claim 3, characterized in that: The fuel cell stack circulation loop also includes a deionizer, which is connected in parallel with the fuel cell stack heat sink; or, the deionizer is connected in parallel with the fuel cell stack; or, the deionizer, the fuel cell stack, and the fuel cell stack heat sink are connected in parallel with each other.

5. The range-extended fuel cell thermal management system according to claim 1, characterized in that: The fuel cell stack circulation loop also includes an intercooler, which is connected in parallel with the fuel cell stack in the fuel cell stack circulation loop.

6. The range-extended fuel cell thermal management system according to claim 1, characterized in that: The refrigeration cycle also includes an evaporator, which is connected in parallel with the first heat exchanger.

7. The range-extended fuel cell thermal management system according to claim 1, characterized in that: The heating circulation loop also includes a warm air core, which is connected in series with the first heat exchanger in the heating circulation loop.

8. A control method for a range-extended fuel cell thermal management system, characterized in that: For the range-extended fuel cell thermal management system as described in any one of claims 1 to 7, when the fuel cell is cold-started, the heating cycle loop heats the fuel cell stack through the first heat exchanger and the fuel cell stack circulation loop; when the fuel cell temperature exceeds a preset calibration value, the cooling cycle loop absorbs heat from the fuel cell stack through the first heat exchanger and the fuel cell stack circulation loop.

9. A car, characterized in that: Includes the range-extended fuel cell thermal management system as described in any one of claims 1 to 7.

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