Cooling System for Fuel Cell Electric Vehicle

Abstract

The present disclosure relates to a cooling system for a fuel cell electric vehicle. The cooling system includes: a stack cooling pipeline for cooling a fuel cell stack of the fuel cell electric vehicle; and a first closed-loop cooling pipeline for cooling at least a part of a first component among components of the vehicle, which generates more heat during braking of the vehicle than during driving of the vehicle.

Description

[0001] Cross - reference to related applications

[0002] This application claims the benefit of priority of a Korean patent application No. 10 - 2019 - 0092507, filed on Jul. 30, 2019 with the Korean Intellectual Property Office, the entire contents of which are incorporated herein by reference. Technical field

[0003] The present disclosure relates to a cooling system for a fuel cell electric vehicle. Background art

[0004] In the case of a fuel cell electric vehicle, it is necessary to cool some components (e.g., a fuel cell stack) constituting the vehicle using a coolant. However, in the case of a commercial vehicle using a fuel cell stack, a retarder or the like must be used as an auxiliary brake to assist the main brake in braking. The heat generated by the retarder during braking is proportional to the weight of the vehicle. Therefore, the heat generated by the retarder of a large commercial vehicle can be very large.

[0005] To cool the retarder, a cooling system with a very high cooling capacity is required. For example, it may be necessary to install a radiator with a very large size to cool the retarder. However, since the retarder usually operates in special situations such as emergency braking, installing a radiator with a very large size in the vehicle is very disadvantageous in terms of space utilization or cost. Alternatively, it may be necessary to over - use a cooling fan to cool the retarder. However, this is also very disadvantageous in terms of energy consumption. Summary of the invention

[0006] The present disclosure is made to solve the above - mentioned problems occurring in the prior art while fully maintaining the advantages achieved by the prior art.

[0007] Aspects of the present disclosure provide a cooling system for a fuel cell electric vehicle, which can effectively cool components having different cooling requirements of the fuel cell electric vehicle within a limited installation space, reduce the size of a heat exchanger (radiator), and reduce the energy consumption of a cooling fan.

[0008] The technical problems to be solved by the present disclosure are not limited to the above problems, and any other technical problems not mentioned herein will be clearly understood by those skilled in the art to which the present disclosure pertains from the following description.

[0009] According to an aspect of the present disclosure, a cooling system for a fuel cell electric vehicle includes: a stack cooling pipeline for cooling a fuel cell stack of the fuel cell electric vehicle; and a first cooling pipeline of a closed-loop type for cooling at least a part of a first component among components of the vehicle, where heat generated during braking of the vehicle is increased compared to that during driving of the vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The above and other objects, features, and advantages of the present disclosure will become more apparent from the following detailed description in conjunction with the accompanying drawings:

[0011] Figure 1 is a schematic diagram showing a cooling system for a fuel cell electric vehicle according to an embodiment of the present disclosure;

[0012] Figure 2 is a graph showing the control of a first valve;

[0013] Figure 3 is a graph showing the control of a cooling fan;

[0014] Figure 4 、 Figure 5 and Figure 6 is a graph showing the control of a pump; and

[0015] Figure 7 is a graph showing the control of a second valve.

[0016] DESCRIPTION OF REFERENCE NUMERALS

[0017] 110: stack cooling pipeline 120: first cooling pipeline

[0018] 130: second cooling pipeline 140: stack heat exchanger

[0019] 141: first heat exchanger 142: second heat exchanger

[0020] 143: auxiliary heat exchanger 150: stack pump

[0021] 151: first pump 152: second pump

[0022] 161: first valve 162: second valve

[0023] 181: first bypass pipeline 182: second bypass pipeline

[0024] 183: heating pipeline 190: processor

[0025] W s : stack coolant W1: first coolant

[0026] W2: second coolant

[0027] T1: Temperature of the first coolant flowing into the first heat exchanger

[0028] T2: Temperature of the second coolant discharged from the second heat exchanger

[0029] T3: Temperature of the stack coolant discharged from the fuel cell stack Detailed implementation manners

[0030] Hereinafter, some embodiments of the present disclosure will be described in detail with reference to the exemplary drawings. When adding reference numerals to the components of each drawing, it should be noted that even if the same or equivalent components are shown in other drawings, they are denoted by the same reference numerals. In addition, when describing the embodiments of the present disclosure, detailed descriptions of well-known features or functions will be excluded so as not to unnecessarily obscure the gist of the present disclosure.

[0031] Reference will be made to Figure 1 describe in detail a cooling system for a fuel cell electric vehicle according to an embodiment of the present disclosure. Figure 1 is a schematic diagram showing a cooling system for a fuel cell electric vehicle according to an embodiment of the present disclosure. As Figure 1 shown, the cooling system according to this embodiment includes a stack cooling pipeline 110 and a first cooling pipeline 120. The cooling system according to this embodiment may further include a second cooling pipeline 130.

[0032] Heap cooling pipeline 110

[0033] The stack cooling pipeline 110 is a flow path for cooling the fuel cell stack S. The fuel cell stack S includes an air electrode (not shown), an electrolyte membrane (not shown), and a fuel electrode (not shown), and since the reaction occurring in the fuel cell stack S is an exothermic reaction, it is necessary to appropriately cool the fuel cell stack S. Due to the general characteristics of the fuel cell stack S, the cooling pipeline 110 for cooling the fuel cell stack S can be provided independently of the cooling pipelines 120 and 130 for cooling components other than the fuel cell stack S.

[0034] A stack heat exchanger 140 may be provided on the stack cooling pipeline 110. The stack heat exchanger 140 is used to cool the stack coolant W flowing along the stack cooling pipeline 110 s . The stack heat exchanger 140 may be an ordinary radiator. The first heat exchanger 141 and the second heat exchanger 142 described below may also be ordinary radiators. The stack coolant W s may be water or an incompressible fluid. The same applies to other coolants described below.

[0035] For pumping the stack coolant W sThe reactor coolant pump 150 can be provided on the reactor coolant pipeline 110. The reactor coolant pump 150 can be an electric water pump for circulating the coolant by means of an electric drive motor. The other pumps 151 and 152 described below can also be electric water pumps. Figure 1 An example is shown in which the reactor coolant pump 150 is installed at a point on the reactor coolant pipeline 110 between the reactor heat exchanger 140 and the fuel cell stack S. However, the installation position of the reactor coolant pump 150 is not limited thereto.

[0036] The second bypass pipeline 182 can be connected to the reactor coolant pipeline 110. The first bypass pipeline 181 connected to the first coolant pipeline 120 will be described separately below. The second bypass pipeline 182 is a flow path for selectively bypassing at least a part of the reactor coolant W discharged from the reactor heat exchanger 140. s For example, the second bypass pipeline 182 can be a flow path for the reactor coolant W that, after being discharged from the reactor heat exchanger 140, does not flow into the fuel cell stack S but flows back into the reactor heat exchanger 140 again. s For this purpose, the second bypass pipeline 182 is provided to connect the point where the reactor coolant W in the reactor coolant pipeline 110 flows into the fuel cell stack S and the point where the reactor coolant W is discharged from the fuel cell stack S. s flows into the fuel cell stack S and the reactor coolant W s is discharged from the fuel cell stack S.

[0037] The second valve 162 can be provided at the point where the reactor coolant pipeline 110 and the second bypass pipeline 182 are connected. The first valve 161 provided at the point where the first coolant pipeline 120 and the first bypass pipeline 181 are connected will be described separately below. The second valve 162 is a valve for regulating the flow rate of the reactor coolant W bypassed to the second bypass pipeline 182. s is a valve for regulating the flow rate of the reactor coolant W bypassed to the second bypass pipeline 182.

[0038] For example, when the fuel cell stack S is at a high temperature, it may be preferable to supply a large amount of the reactor coolant W s into the fuel cell stack S. In this case, the flow rate of the reactor coolant W bypassed to the second bypass pipeline 182 can be reduced by controlling the second valve 162. Optionally, when the fuel cell stack S is at a low temperature, it may be preferable to supply a small amount of the reactor coolant W s into the fuel cell stack S. In this case, the flow rate of the reactor coolant W bypassed to the second bypass pipeline 182 can be increased by controlling the second valve 162. s into the fuel cell stack S. In this case, the flow rate of the reactor coolant W bypassed to the second bypass pipeline 182 can be increased by controlling the second valve 162. s The flow rate of the reactor coolant W bypassed to the second bypass pipeline 182 can be increased by controlling the second valve 162.

[0039] The second valve 162 may be a three-way control valve. A three-way control valve is a valve having two fluid inlets i1 and i2 and one fluid outlet o. The three-way control valve can adjust the flow rates of two fluids flowing in through the two fluid inlets i1 and i2 respectively by adjusting the opening degree between any one of the fluid inlets and the fluid outlet and the opening degree between the other fluid inlet and the fluid outlet. More specifically, the second valve 162 may be a thermostat operated according to the temperature T3 of the reactor coolant W s of the fuel cell electric vehicle.

[0040] First cooling pipeline 120 and second cooling pipeline 130

[0041] The first cooling pipeline 120 is a flow path for cooling at least some of the components in the first component of the fuel cell electric vehicle. The second cooling pipeline 130 is a flow path for cooling at least some of the components in the second component of the fuel cell electric vehicle. The first component refers to the component among the components of the fuel cell electric vehicle that need to be cooled and generates more heat during vehicle braking than during vehicle driving. The second component refers to the component other than the first component among the components of the fuel cell electric vehicle that need to be cooled. Here, vehicle driving refers to the driving conditions other than vehicle braking, and includes vehicle accelerating driving and constant speed driving. Here, vehicle driving can be expressed as the driving condition during non-braking, and braking can be expressed as the braking condition. The first component may be a component that generates more heat when the vehicle brakes than when the vehicle accelerates or drives at a constant speed. For example, the first component may be a component that generates more heat as the vehicle brakes. When the vehicle is driving, the fuel cell stack S can generate electricity.

[0042] The components of the fuel cell electric vehicle may include components that generate more heat as the vehicle drives, components that generate more heat as the vehicle brakes, and components that do not generate heat according to a specific trend of either vehicle driving or braking.

[0043] The fuel cell stack S is a component that generates more heat as the vehicle drives (for example, as the vehicle accelerates, the fuel cell stack S generates electricity). When the power generation load increases, the heat generated by the fuel cell stack S also increases. For example, as the vehicle accelerates, the power generated by the fuel cell stack S increases, and as the power generated by the fuel cell stack S increases, the heat generated by the fuel cell stack S also increases. The components related to the fuel cell stack S generate heat similarly to the above. The components include a bi-directional high voltage DC-DC converter (BHDC) C1 provided between the fuel cell stack S and the high voltage battery B, an air compressor that compresses air and supplies the compressed air to the air electrode of the fuel cell stack S, and an air cooler that cools the air compressed by the air compressor, etc. The combination of the air compressor and the air cooler is inFigure 1 is represented by A in the figure. When the vehicle brakes, the heat generated by the fuel cell stack S or its related components decreases. For example, during braking of the vehicle, since the amount of power generated by the fuel cell stack S decreases, the heat generated by the fuel cell stack S also decreases.

[0044] The retarder R is a component whose heat generation increases as the vehicle brakes. When the required braking force increases, the heat generated by the retarder R also increases. The retarder R is provided in the transmission T connected to the drive motor M that drives the vehicle and serves as an auxiliary brake. For example, as the vehicle brakes by the operation of the retarder R, the heat generated by the retarder R increases. The same applies even when a heater resistor is provided as an auxiliary brake. In the case of an auxiliary brake, when the vehicle is driven without braking, the heat generation decreases (almost no heat is generated).

[0045] The drive motor M does not have a specific tendency to generate heat during both vehicle driving and vehicle braking. The drive motor M generates heat according to the driving load during vehicle driving and generates heat according to regenerative braking during vehicle braking. The inverter I that converts the DC voltage supplied from the high-voltage battery B into the three-phase AC voltage required to drive the drive motor M also similarly generates heat. The low-voltage DC-DC converter (LDC) C2 that converts the high DC voltage supplied from the high-voltage battery B into a low DC voltage and the accessory D both generate heat independently of driving and braking. The accessory can be a cooling fan, a power steering oil cooler, etc.

[0046] The cooling system of this embodiment cools components using separate cooling pipelines according to the heat generation characteristics of the components to be cooled. That is, the cooling system of this embodiment separately includes: a cooling pipeline 110 for cooling the fuel cell stack S, which is a component whose heat generation increases as the vehicle drives; and a cooling pipeline 120 for cooling the first component, which is a component whose heat generation increases as the vehicle brakes. In addition, the cooling system of this embodiment can separately include: a cooling pipeline 130 for cooling the second component, which is a component other than the fuel cell stack S and the first component. Therefore, the cooling system of this embodiment can construct or operate the cooling pipelines according to the heat generation characteristics of the components, thereby effectively cooling components with different cooling requirements due to different heat generation characteristics within a limited installation space.

[0047] In Figure 1In the cooling system shown, the stack cooling pipeline 110 is a pipeline for cooling the fuel cell stack S, the first cooling pipeline 120 is a pipeline for cooling the retarder R, which is one of the first components, and the second cooling pipeline 130 is a pipeline for cooling the drive motor M, which is one of the second components. The oil for driving the retarder R can be cooled by the first coolant W1 flowing along the first cooling pipeline 120 in the oil cooler. In the oil cooler, the first coolant W1 can cool the oil for the transmission T. That is, the heat of the transmission oil can be transferred from the oil cooler to the first coolant W1.

[0048] The cooling pipelines of this embodiment can be set in a closed-loop type. That is, as Figure 1 shown, the cooling pipelines of this embodiment can be set so that the coolant circulates through the cooling pipelines.

[0049] At the same time, the first heat exchanger 141 and the second heat exchanger 142 can be respectively arranged on the first cooling pipeline 120 and the second cooling pipeline 130. The first heat exchanger 141 is used to cool the first coolant W1 flowing along the first cooling pipeline 120. The second heat exchanger 142 is used to cool the second coolant W2 flowing along the second cooling pipeline 130. As described above, in the case of the cooling system of this embodiment, separate heat exchangers can be arranged on each cooling pipeline. Considering the characteristics required for each cooling pipeline, the cooling system of this embodiment can separately design or operate the heat exchangers arranged on each cooling pipeline, thereby improving the cooling efficiency. Therefore, the heat exchangers arranged on each cooling pipeline can have different cooling capacities or can have different sizes.

[0050] At the same time, the first cooling pipeline 120 can cool the retarder actuator R, which is one of the first components. The second cooling pipeline 130 can cool the drive motor M, which is one of the second components. The temperature required for the first coolant W1 to cool the retarder R is higher than the temperature required for the second coolant W2 to cool the drive motor M.

[0051] Therefore, when the first coolant W1 is used in the heating chamber E, the heating performance can be improved compared with when the second coolant W2 is used. In addition, since the first coolant W1 receives the heat of the stack coolant W s through the auxiliary heat exchanger 143 described below when the vehicle is driving, the first coolant W1 is more advantageous for the heating chamber E.

[0052] In order to heat the interior of the vehicle, the cooling system of this embodiment can further include a heating pipeline 183 connected to the first cooling pipeline 120. The heating pipeline 183 can be arranged to connect the point where the first coolant W1 of the first cooling pipeline 120 flows into the first heat exchanger 141 and the point where the first coolant W1 discharges from the first heat exchanger 141.

[0053] Auxiliary heat exchanger 143

[0054] The cooling system of this embodiment may further include: an auxiliary heat exchanger 143 for heat exchange between the reactor coolant W s and the first coolant W1. The auxiliary heat exchanger 143 may be arranged to effect heat exchange between the reactor coolant W s before flowing into the reactor heat exchanger 140 and the first coolant W1 before flowing into the first heat exchanger 141. For example, as Figure 1 shown, the auxiliary heat exchanger 143 may be arranged to effect heat exchange between the reactor coolant W discharged from the fuel cell stack S to the reactor heat exchanger 140 s and the first coolant W1 discharged from the oil cooler to the first heat exchanger 141.

[0055] Since the cooling system of this embodiment can share the cooling capacity required by either the reactor heat exchanger 140 or the first heat exchanger 141 to the other through the auxiliary heat exchanger 143, the sizes of the reactor heat exchanger 140 and the first heat exchanger 141 can be reduced, and the energy consumption of the cooling fan F can be decreased. Specific descriptions will be given hereinafter.

[0056] When the vehicle is being driven, the heat generated by the fuel cell stack S increases according to the power generation load, and the heat generated by the first component such as the retarder brake R decreases. Therefore, the heat to be cooled in the reactor heat exchanger 140 increases, and the heat to be cooled in the first heat exchanger 141 decreases. Therefore, when the vehicle is being driven, the first heat exchanger 141 has additional cooling capacity (margin) compared with when the vehicle is braking.

[0057] When the vehicle is being driven, the cooling system of this embodiment can utilize the additional cooling capacity of the first heat exchanger 141 through the auxiliary heat exchanger 143. Since when the vehicle is being driven, the temperature T3 of the reactor coolant W s is higher than the temperature T1 of the first coolant W1, the heat of the reactor coolant W s can be transferred to the first coolant W1 through the auxiliary heat exchanger 143. The heat transferred to the first coolant W1 can be cooled by the first heat exchanger 141. Therefore, when the auxiliary heat exchanger 143 is provided, the cooling capacity required by the reactor heat exchanger 140 is reduced compared with when the auxiliary heat exchanger 143 is not provided. The size of the reactor heat exchanger 140 is also reduced. The cooling fan F is a fan for blowing external air to the heat exchanger. When the cooling of the generated heat is shared between the reactor heat exchanger 140 and the first heat exchanger 141, the amount of external air that the cooling fan F needs to blow is also reduced. Therefore, the energy consumption of the cooling fan F is decreased.

[0058] When the vehicle brakes, the heat generated by the fuel cell stack S decreases, and the heat generated by the first component increases. Therefore, compared with when the vehicle is driving, when the vehicle brakes, the stack heat exchanger 140 has additional cooling capacity. When the vehicle brakes, the cooling system of this embodiment can utilize the additional cooling capacity of the stack heat exchanger 140 through the auxiliary heat exchanger 143. When the vehicle brakes, the heat of the first coolant W1 can be transferred to the stack coolant W through the auxiliary heat exchanger 143. s . The heat transferred to the stack coolant W s can be cooled by the stack heat exchanger 140.

[0059] However, when any coolant is not sufficiently cooled in the heat exchanger due to the heat transferred through the auxiliary heat exchanger 143, problems may occur in the cooling of the components. For example, when the first coolant W1 is not sufficiently cooled to the temperature required to cool the auxiliary brake in the first heat exchanger 141 due to the heat transferred from the stack coolant W s during the driving of the vehicle, the first coolant W1 cannot cool the auxiliary brake to the temperature required by the system. To prevent this situation, the cooling system of this embodiment can further include a first bypass line 181.

[0060] The first bypass line 181 is a flow path for selectively bypassing at least a part of the first coolant W1. As Figure 1 shown, the first bypass line 181 connects the point where the first coolant W1 in the first cooling line 120 flows into the auxiliary heat exchanger 143 and the point where the first coolant W1 discharges from the auxiliary heat exchanger 143. A first valve 161 can be provided at the point where the first cooling line 120 and the first bypass line 181 are connected. The first valve 161 is a valve for regulating the flow rate of the first coolant W1 bypassed to the first bypass line 181. The first valve 161 can be a three-way control valve.

[0061] Meanwhile, the first cooling pipeline 120 can be arranged to additionally cool at least one of the BHDC C1, the air compressor, and the air cooler A, as well as the auxiliary brake which is one of the first components. As described above, the BHDC C1, the air compressor, and the air cooler A are components whose heat generation increases with vehicle driving. The BHDC C1, the air compressor, and the air cooler A do not correspond to the first components. Since the first cooling pipeline 120 is a flow path for cooling the first components that generate heat when the vehicle brakes, when the vehicle is driving, the first cooling pipeline 120 bears very little heat. Therefore, when the first cooling pipeline 120 cools some of the components whose heat generation increases with vehicle driving, the cooling system can be designed and operated more effectively. The cooling system can be configured such that the first cooling pipeline 120 cools other components related to the fuel cell stack S and whose heat generation increases according to the power generation load when the vehicle is driving.

[0062] The second cooling pipeline 130 can be arranged to additionally cool at least one of the accessory D, the LDC C2, and the inverter I, as well as the drive motor M which is one of the second components. The second components are components that do not exhibit different heat generation characteristics during vehicle driving and vehicle braking. The second components are components that generate heat both during vehicle driving and vehicle braking.

[0063] Control of the cooling system

[0064] The cooling system of the present embodiment may further include a processor 190 for control. The processor 190 can execute at least one of the controls described below. For reference, the processor 190 may include a microprocessor. In addition, the processor 190 may include a memory that stores a plurality of control instructions, and based on the control instructions, the processor generates instructions for controlling the components.

[0065] First, the control of the first valve 161 will be described. The processor 190 can be connected to the first valve 161 to control the first valve 161.

[0066] When the temperature T1 of the first coolant W1 flowing into the first heat exchanger 141 during vehicle driving is higher than or equal to the first reference temperature, the processor 190 can control the first valve 161 to bypass the first coolant W1 to the first bypass pipeline 181.

[0067] For example, when during vehicle driving, with the stack coolant W sThe heat is transferred to the first coolant W1 through the auxiliary heat exchanger 143. When the temperature T1 of the first coolant W1 flowing into the first heat exchanger 141 reaches 80°C, due to the cooling capacity limitation of the first heat exchanger 141, the first coolant W1 discharged from the first heat exchanger 141 may not be cooled to the required temperature. In this case, it may be preferable that the heat of the reactor coolant W s is not transferred to the first coolant W1. The processor 190 can control the first valve 161 according to the temperature T1 of the first coolant W1 flowing into the first heat exchanger 141 to change the flow rate of the first coolant W1 bypassed to the first bypass line 181.

[0068] The temperature of 80°C is an example of the first reference temperature. In a fuel cell electric vehicle, the allowable temperature of the coolant is typically lower than 85°C. The temperature of 80°C is determined considering this. As described above, the first reference temperature can be determined considering the allowable temperature of the coolant.

[0069] When the temperature T3 of the reactor coolant W flowing into the auxiliary heat exchanger 143 during braking s is higher than or equal to the second reference temperature, the processor 190 can control the first valve 161 to bypass the first coolant W1 to the first bypass line 181.

[0070] For example, when the temperature T3 of the reactor coolant W flowing into the auxiliary heat exchanger 143 during braking s reaches 85°C, the reactor coolant W discharged from the reactor heat exchanger 140 s may not be cooled to the required temperature. In this case, it may be preferable that the heat of the first coolant W1 is not transferred to the reactor coolant W s . As Figure 2 shown, the processor 190 can control the first valve 161 according to the temperature T3 of the reactor coolant W flowing into the auxiliary heat exchanger 143 s to change the flow rate of the first coolant W1 bypassed to the first bypass line 181.

[0071] Figure 2 is a graph showing the control of the first valve. For reference, as Figure 2 the valve angle command of increases, the opening degree for the first bypass line 181 increases, and the flow rate of the bypassed first coolant W1 also increases.

[0072] Second, the control of the cooling fan F will be described. The processor 190 may be connected to the cooling fan F to control the cooling fan F. When the vehicle is driven, the processor 190 may control the cooling fan F based on at least one of the temperature T1 of the first coolant W1 flowing into the first heat exchanger 141, the temperature T2 of the second coolant W2 discharged from the second heat exchanger 142, and the temperature T3 of the stack coolant W discharged from the fuel cell stack S. When the temperature of the coolant increases, the operating RPM of the cooling fan F also needs to increase. As shown in s shown, as the temperature of the coolant increases, the cooling requirement value increases, and when the cooling requirement value increases, it is preferable to increase the operating RPM of the cooling fan F. Figure 3 FIG.

[0073] Figure 3 is a graph showing the control of the cooling fan. Based on the temperatures T1, T2, and T3 of the coolant, the cooling fan F may be controlled to operate at an output corresponding to a certain percentage of the maximum output. Figure 3 The cooling requirement value of FIG. represents a percentage. In addition, when the temperatures T1, T2, and T3 of the coolant are different from each other, the cooling fan F may be operated according to the maximum requirement value among the requirement values.

[0074] Third, the control of the pumps will be described. The processor 190 may be connected to the following pumps to control the pumps. The cooling system of the present embodiment may include: a stack pump 150 provided on the stack cooling pipeline 110 to pump the stack coolant W s ; a first pump 151 provided on the first cooling pipeline 120 to pump the first coolant W1; and a second pump 152 provided on the second cooling pipeline 130 to pump the second coolant W2.

[0075] When the vehicle is driven, the processor 190 may control the stack pump 150 based on the temperature T3 of the stack coolant W discharged from the fuel cell stack S. In addition, when the vehicle is driven, the processor 190 may control the first pump 151 based on the temperature T1 of the first coolant W1 flowing into the first heat exchanger 141. Further, when the vehicle is driven, the processor 190 may control the second pump 152 based on the temperature T2 of the second coolant W2 discharged from the second heat exchanger 142. When the temperature of the coolant increases, the operating RPM of the pump may preferably increase to increase the flow rate of the coolant. As shown in s FIG. Figures 4 to 6 shown, as the temperature of the coolant increases, the cooling requirement value increases, and when the cooling requirement value increases, it is preferable to increase the operating RPM of the pump. Figures 4 to 6 is a graph showing the control of the pump.

[0076] Fourth, the control of the stack pump 150 will be described. The processor 190 may be connected to the stack pump 150 to control the stack pump 150. When the vehicle brakes, the processor 190 may control the stack pump 150 such that the operating RPM of the stack pump 150 is higher than or equal to the reference RPM. When the vehicle brakes, the heat of the first coolant W1 may be transferred to the stack coolant W through the auxiliary heat exchanger 143. s To transfer more heat, the stack coolant W s may preferably flow quickly. For this purpose, when the vehicle brakes, the processor 190 may control the stack pump 150 such that the operating RPM of the stack pump 150 is equal to the maximum RPM among the allowable RPMs of the stack pump 150.

[0077] Fifth, the control of the second valve 162 will be described. The processor 190 may be connected to the second valve 162 to control the second valve 162. When the vehicle brakes, the processor 190 may control the second valve 162 such that the opening degree of the second bypass line 182 is higher than or equal to the reference opening degree.

[0078] The second valve 162 may include: a first inlet i1 through which the coolant discharged from the fuel cell stack S flows in; a second inlet i2 through which the coolant bypassed through the second bypass line 182 flows in; and an outlet o through which the coolant is discharged. When the opening degree between the second inlet i2 and the outlet o, that is, the opening degree of the second bypass line 182, increases, the flow rate of the bypassed coolant also increases. When the vehicle brakes, problems caused by overheating of the fuel cell stack S are less likely to occur. Therefore, it may be more preferable to use the stack coolant W s to cool the auxiliary brake. For this purpose, when the vehicle brakes, the processor 190 may control the second valve 162 such that the opening degree of the second bypass line 182 is equal to the maximum opening degree among the allowable opening degrees.

[0079] As a reference, as Figure 7 shown, when the vehicle is driving, as the temperature T3 of the stack coolant W s increases, it may be preferable to increase the opening degree between the first inlet i1 and the outlet o, that is, the opening degree of the stack cooling line 110. Figure 7 is a graph showing the control of the second valve.

[0080] According to the present disclosure, the cooling system uses separate cooling lines to cool the components that need to be cooled according to the heat generation characteristics of the components, thereby constructing or operating the cooling lines according to the heat generation characteristics of the components, and thus effectively cooling the components with different cooling requirements within a limited installation space.

[0081] In addition, according to the present disclosure, the cooling system shares the required cooling capacity of one of the reactor heat exchanger and the first heat exchanger with the other through an auxiliary heat exchanger, thereby reducing the sizes of the reactor heat exchanger and the first heat exchanger and reducing the energy consumption of the cooling fan.

[0082] In the foregoing, although the present disclosure has been described with reference to the exemplary embodiments and the drawings, the present disclosure is not limited thereto, but those skilled in the art to which the present disclosure pertains can make various modifications and changes to the present disclosure without departing from the spirit and scope of the present disclosure claimed in the appended claims. Therefore, the exemplary embodiments of the present disclosure are provided to explain the spirit and scope of the present disclosure, but do not limit the spirit and scope of the present disclosure, such that the spirit and scope of the present disclosure are not limited by the embodiments. The scope of the present disclosure should be construed based on the appended claims, and all technical ideas within the scope equivalent to the claims should be included within the scope of the present disclosure.

Claims

1. A cooling system for a fuel cell electric vehicle, the cooling system comprising: A stack cooling pipeline for cooling the fuel cell stack of the fuel cell electric vehicle; A first closed-loop cooling pipeline for cooling at least a part of a first component in the components of the fuel cell electric vehicle, where the heat generated during braking of the fuel cell electric vehicle is greater than that generated during driving of the fuel cell electric vehicle; A stack heat exchanger for cooling the stack coolant flowing along the stack cooling pipeline; A first heat exchanger for cooling the first coolant flowing along the first cooling pipeline; An auxiliary heat exchanger for performing heat exchange between the stack coolant before flowing into the stack heat exchanger and the first coolant before flowing into the first heat exchanger; A second closed-loop cooling pipeline for cooling at least a part of a second component other than the first component in the components of the fuel cell electric vehicle, where the second component generates heat during both driving and braking of the fuel cell electric vehicle; Wherein, during driving of the fuel cell electric vehicle, the auxiliary heat exchanger transfers the heat of the stack coolant to the first coolant to share the cooling capacity required to cool the stack coolant to the first heat exchanger, and During braking of the fuel cell electric vehicle, the auxiliary heat exchanger transfers the heat of the first coolant to the stack coolant to share the cooling capacity required to cool the first coolant to the stack heat exchanger.

2. The cooling system according to claim 1, further comprising: A first bypass pipeline connecting a point where the first coolant of the first cooling pipeline flows into the auxiliary heat exchanger and another point where the first coolant of the first cooling pipeline discharges from the auxiliary heat exchanger to selectively bypass at least a part of the first coolant flowing along the first cooling pipeline.

3. The cooling system according to claim 2, further comprising: A first valve provided at an intersection between the first cooling pipeline and the first bypass pipeline; And A processor connected to the first valve, Wherein during driving of the fuel cell electric vehicle, when the temperature of the first coolant flowing into the first heat exchanger is higher than or equal to a reference temperature, the processor controls the first valve to bypass the first coolant to the first bypass pipeline.

4. The cooling system according to claim 2, further comprising: A first valve provided at an intersection between the first cooling pipeline and the first bypass pipeline; And A processor connected to the first valve, Wherein during braking of the fuel cell electric vehicle, when the temperature of the stack coolant flowing into the auxiliary heat exchanger is higher than or equal to a reference temperature, the processor controls the first valve to bypass the first coolant to the first bypass pipeline.

5. The cooling system according to claim 1, further comprising: A closed-loop second cooling pipeline for cooling at least a part of the second components other than the first component among the components of the fuel cell electric vehicle.

6. The cooling system according to claim 1, further comprising: A second heat exchanger for cooling the second coolant flowing along the second cooling pipeline.

7. The cooling system according to claim 6, further comprising: A cooling fan for blowing external air to the stack heat exchanger, the first heat exchanger, and the second heat exchanger; And A processor connected to the cooling fan, wherein during the driving of the fuel cell electric vehicle, the processor controls the cooling fan based on at least one of the temperature of the stack coolant discharged from the fuel cell stack, the temperature of the first coolant flowing into the first heat exchanger, and the temperature of the second coolant discharged from the second heat exchanger.

8. The cooling system according to claim 6, further comprising: A stack pump provided on the stack cooling pipeline to pump the stack coolant; A first pump provided on the first cooling pipeline to pump the first coolant; A second pump provided on the second cooling pipeline to pump the second coolant; And A processor connected to the stack pump, the first pump, and the second pump, wherein during the driving of the fuel cell electric vehicle, the processor controls the stack pump based on the temperature of the stack coolant discharged from the fuel cell stack, controls the first pump based on the temperature of the first coolant flowing into the first heat exchanger, and controls the second pump based on the temperature of the second coolant discharged from the second heat exchanger.

9. The cooling system according to claim 1, further comprising: A stack pump provided on the stack cooling pipeline to pump the stack coolant discharged from the stack heat exchanger; And A processor connected to the stack pump, wherein during the braking of the fuel cell electric vehicle, the processor controls the stack pump such that the operating RPM of the stack pump is higher than or equal to the reference RPM.

10. The cooling system according to claim 1, further comprising: A second bypass pipeline connecting a point where the stack coolant of the stack cooling pipeline flows into the fuel cell stack and another point where the stack coolant of the stack cooling pipeline is discharged from the fuel cell stack to selectively bypass at least a part of the stack coolant flowing along the stack cooling pipeline; A second valve provided at the intersection between the stack cooling pipeline and the second bypass pipeline; And A processor connected to the second valve, wherein during the braking of the fuel cell electric vehicle, the processor controls the second valve such that the opening degree of the second bypass pipeline is higher than or equal to the reference opening degree.

11. In the cooling system according to claim 1, the first cooling pipeline cools an auxiliary brake which is one of the first components, and the auxiliary brake is provided in a transmission connected to a drive motor for driving the fuel cell electric vehicle to assist the braking force of the fuel cell electric vehicle.

12. The cooling system according to claim 11, wherein, the first cooling pipeline additionally cools at least one of a bidirectional high-voltage DC-DC converter (BHDC) disposed between the fuel cell stack and the high-voltage battery, an air compressor that compresses air and supplies the compressed air to the cathode of the fuel cell stack, and an air cooler that cools the compressed air.

13. The cooling system according to claim 5, wherein, the second cooling pipeline cools a drive motor for driving the fuel cell electric vehicle, which is one of the second components.

14. The cooling system according to claim 13, wherein, the second cooling pipeline additionally cools at least one of a low-voltage DC-DC converter that converts the DC high voltage supplied from the high-voltage battery into a DC low voltage and an inverter that converts the DC voltage supplied from the high-voltage battery into a three-phase AC voltage required to drive the drive motor.

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