Vehicle fuel cell system

Abstract

To cool a fuel battery stack effectively when a vehicle is parked to guarantee high output of fuel batteries and improve safety and reliability.SOLUTION: A vehicular fuel battery system includes: a first cooling line 110 in which a first coolant is circulated via a fuel battery stack 10 of a vehicle; a first cooling part 60 which is provided at the first cooling line and cools the first coolant; and a second cooling part 80 which is provided at the first cooling line and cools the first coolant separately from the first cooling part.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a fuel cell system for a vehicle, and more particularly, to a fuel cell system for a vehicle that can ensure high output of a fuel cell stack and improve safety and reliability. [Background technology]

[0002] 2. Description of the Related Art A fuel cell system is a system that produces electrical energy through a chemical reaction of fuel, and has been continuously researched and developed as an alternative solution to global environmental problems.

[0003] Fuel cell systems can be classified into phosphoric acid fuel cells (PAFCs), molten carbonate fuel cells (MCFCs), solid oxide fuel cells (SOFCs), polymer electrolyte membrane fuel cells (PEMFCs), alkaline fuel cells (AFCs), direct methanol fuel cells (DMFCs), etc. depending on the type of electrolyte used. They can be used in a variety of applications, such as for mobile power sources, transportation, and distributed power generation, depending on the type of fuel used as well as the operating temperature, output range, etc.

[0004] A fuel cell system includes a fuel cell stack that generates electrical energy, a fuel supply device that supplies fuel (hydrogen) to the fuel cell stack, an air supply device that supplies oxygen from the air, which is an oxidant necessary for the electrochemical reaction, to the fuel cell stack, and a thermal management system (TMS) that removes the reaction heat from the fuel cell stack outside the system, controls the operating temperature of the fuel cell stack, and performs water management functions.

[0005] The thermal management system (TMS) is a type of cooling device that circulates antifreeze, which acts as a coolant, through the fuel cell stack to maintain an appropriate temperature (e.g., 60 to 70°C), and may include a TMS line through which the coolant that cools the fuel cell stack circulates, a reservoir in which the coolant is stored, a pump that circulates the coolant, an ion filter that removes ions contained in the coolant, and a radiator that releases heat from the coolant to the outside. The thermal management system may also include a heater that heats the coolant, and an air conditioning unit (e.g., a heater) that uses the coolant to heat and cool the interior of the vehicle.

[0006] Meanwhile, recently, various attempts have been made to apply fuel cell systems not only to passenger cars (or commercial vehicles) but also to construction machinery.

[0007] In the case of passenger cars, high output from the fuel cell stack is required while the car is traveling, and the fuel cell stack can be cooled via the radiator using the wind generated by the vehicle speed.

[0008] On the other hand, since construction machinery performs work while stopped (e.g., leveling, loading), high output from the fuel cell stack is required while the machinery is stopped. However, there is a problem that the volume of air generated by the cooling fan is not enough to sufficiently cool the fuel cell stack, which reduces the safety and durability of the fuel cell stack.

[0009] Accordingly, various researches have been conducted recently to effectively cool the fuel cell stack when high output is required from the fuel cell stack while the vehicle is stopped, but the results are still insufficient, and further development is required in this regard. Summary of the Invention [Problem to be solved by the invention]

[0010] SUMMARY OF THE DISCLOSURE An object of the present invention is to provide a fuel cell system for a vehicle that can ensure high output of a fuel cell stack and improve safety and reliability.

[0011] In particular, an embodiment of the present invention aims to be able to effectively cool a fuel cell stack in a situation where high output from the fuel cell stack is required while the vehicle is stopped, thereby improving the operating performance and efficiency of the fuel cell stack.

[0012] Another object of the present invention is to minimize a decrease in cooling performance caused by a decrease in the flow rate of coolant flowing into a fuel cell stack.

[0013] The problems to be solved by the embodiments are not limited to those described above, and may also include the means for solving the problems described below and the objectives and effects that can be grasped from the embodiments. [Means for solving the problem]

[0014] According to a preferred embodiment of the present invention for achieving the above-mentioned object of the present invention, a fuel cell system for a vehicle includes a first cooling line through which a first coolant is circulated via a fuel cell stack of the vehicle, a first cooling section provided in the first cooling line for cooling the first coolant, and a second cooling section provided in the first cooling line for cooling the first coolant separately from the first cooling section.

[0015] This is to ensure high output of the fuel cell stack and to improve safety and reliability.

[0016] That is, in the case of passenger cars, high output is required from the fuel cell stack while driving, and the fuel cell stack can be cooled via the radiator using the wind generated by the vehicle speed. On the other hand, in construction machinery, work (e.g., leveling work, loading work) is performed while the vehicle is stopped, so high output is required from the fuel cell stack while the vehicle is stopped, but there is a problem that the amount of wind generated by the cooling fan is not enough to sufficiently cool the fuel cell stack, and there is a problem that the safety and durability of the fuel cell stack are reduced.

[0017] However, in an embodiment of the present invention, the first cooling water flowing into the fuel cell stack is cooled separately by the first cooling section and the second cooling section, thereby ensuring high output of the fuel cell stack and achieving advantageous effects of improving safety and reliability.

[0018] Above all, the embodiment of the present invention can further lower the temperature of the first coolant when a vehicle (e.g., construction machinery) that cannot use wind while traveling is stopped, thereby achieving the advantageous effect of ensuring high-power operation of the fuel cell stack and improving safety and durability.

[0019] As the first cooling unit, various cooling means capable of cooling the first cooling water may be used.

[0020] As an example, the first cooling unit may include a first radiator provided in the first cooling line to cool the first coolant.

[0021] The second cooling unit may be any of various cooling means capable of cooling the first cooling water separately from the first cooling unit.

[0022] As an example, the second cooling unit may include a first branch line branched off from the first cooling line, and a second radiator provided in the first branch line so as to be connected in parallel to the first radiator, and cooling the first coolant.

[0023] Preferably, one end of the first branch line is connected to the first cooling line between the outlet of the fuel cell stack and the inlet of the first radiator, and the other end of the first branch line is connected to the first cooling line between the outlet of the first radiator and the inlet of the fuel cell stack.

[0024] More preferably, the first branch line may be provided with a first opening / closing valve that selectively opens and closes the first branch line.

[0025] When the first opening / closing valve opens the first branch line, the first cooling water can be cooled via the first radiator and also via the second radiator. On the other hand, when the first opening / closing valve blocks the first branch line, the first cooling water passes only through the first radiator without passing through the second radiator, so that the first cooling water can be cooled only by the first radiator.

[0026] According to a preferred embodiment of the present invention, the fuel cell system for a vehicle may include a first pump provided in a first cooling line for pumping the first cooling water, and a flow rate control unit provided in the first cooling line for controlling the flow rate of the first cooling water flowing into the fuel cell stack separately from the first pump.

[0027] This is to prevent a decrease in the cooling efficiency of the fuel cell stack due to an insufficient flow rate of the first cooling water. That is, during high-output operation of the fuel cell stack, even if the temperature of the first cooling water is within the appropriate temperature range, if the flow rate of the first cooling water is smaller than the target flow rate (set flow rate), the cooling efficiency of the fuel cell stack decreases.

[0028] However, the present invention can achieve the advantageous effect of minimizing the decrease in the flow rate of the first coolant flowing into the fuel cell stack by providing a flow rate control unit that controls the flow rate of the first coolant on the first cooling line.

[0029] The flow rate adjusting unit may be provided in various structures capable of adjusting the flow rate of the first cooling water.

[0030] As an example, the flow rate regulator may include a second branch line branched off from the first cooling line, and a second pump provided in the second branch line to be connected in parallel to the first pump and to pump the first cooling water.

[0031] Preferably, one end of the second branch line is connected to the first cooling line between the outlet of the first radiator and the first pump, and the other end of the second branch line is connected to the first cooling line between the first pump and the inlet of the fuel cell stack.

[0032] More preferably, the second branch line may be provided with a second opening / closing valve that selectively opens and closes the second branch line.

[0033] When the second opening / closing valve opens the second branch line, the first cooling water can be pumped by the first pump and the second pump at the same time, whereas when the second opening / closing valve blocks the second branch line, the first cooling water can be pumped only by the first pump and the first cooling water pumped by the first pump can be blocked from flowing into the second pump.

[0034] According to a preferred embodiment of the present invention, the fuel cell system may include a second cooling line through which a second cooling water is circulated via power electronic parts of the vehicle, and a third radiator provided in the second cooling line for cooling the second cooling water.

[0035] As an example, the electrical components may include at least one of a BHDC (Bi-directional High voltage DC-DC Converter) provided between the fuel cell stack and the vehicle's high voltage battery, a BPCU (Blower Pump Control Unit) that controls a blower that supplies outside air for driving the fuel cell stack, a LDC (Low-Voltage DC-DC Converter) that converts high DC voltage supplied from the high voltage battery to low DC voltage, an ACP (Air Compressor) that compresses air supplied to the fuel cell stack, and an air cooler.

[0036] Preferably, the first radiator and the third radiator are arranged side by side, and include a first cooling fan that blows outside air to the first radiator and the third radiator.

[0037] In this manner, by allowing the first radiator and the third radiator to be cooled simultaneously by only one first cooling fan, the structure can be simplified, and design freedom and space utilization can be improved, and the advantageous effect of minimizing power consumption for cooling the first radiator and the third radiator can be obtained.

[0038] According to a preferred embodiment of the present invention, a second cooling fan may be included which blows outside air to the second radiator.

[0039] According to a preferred embodiment of the present invention, a fuel cell system for a vehicle may include: a first connection line having one end connected to a first cooling line between an outlet of a first radiator and an inlet of a fuel cell stack, and another end connected to the first cooling line between the outlet of the fuel cell stack and the inlet of the first radiator; a heater provided in the first connection line for heating a first cooling water flowing along the first connection line; and a second connection line connected to the first cooling line between the outlet of the first radiator and the inlet of the fuel cell stack via an air conditioning unit of the vehicle, through which the first cooling water circulates. [Brief description of the drawings]

[0040] [Figure 1] 1 is a diagram for explaining a fuel cell system for a vehicle according to the present invention; [Diagram 2] FIG. 2 is a diagram illustrating a second cooling unit and a flow rate adjusting unit in a fuel cell system for a vehicle according to the present invention. [Diagram 3] FIG. 2 is a diagram illustrating a first connecting line and a second connecting line in the vehicle fuel cell system according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0041] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0042] However, the technical concept of the present invention is not limited to the embodiments described, but may be embodied in various different forms, and any one or more of the components between the embodiments may be selectively combined or substituted within the scope of the technical concept of the present invention.

[0043] Furthermore, terms (including technical and scientific terms) used in the embodiments of the present invention may be interpreted as meanings that may be commonly understood by a person having ordinary knowledge in the technical field to which the present invention belongs, unless otherwise clearly and specifically defined and described, and commonly used terms, such as predefined terms, may be interpreted in consideration of the contextual meaning of the relevant art.

[0044] Furthermore, the terms used in the embodiments of the present invention are intended to describe the embodiments and are not intended to limit the present invention.

[0045] In this specification, unless otherwise specified, the singular form can also include the plural form, and when describing "A and (and) at least one (or more) of B and C," it can include one or more of all possible combinations of A, B, and C.

[0046] Additionally, in describing components of embodiments of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used.

[0047] Such terms are used only to distinguish a component from other components, and do not limit the essence, order, or procedure of the component.

[0048] Furthermore, when a component is described as being "coupled," "coupled," or "connected" to another component, it includes not only cases in which the component is directly coupled, coupled, or connected to the other component, but also cases in which the component is "coupled," "coupled," or "connected" between the other component and the other component or by other components.

[0049] In addition, when described as being formed or disposed "above or below" each component, "above" or "below" includes not only the case where two components are in direct contact with each other, but also the case where one or more other components are formed or disposed between the two components. In addition, when described as "above or below," it can include not only the upper direction based on one component, but also the lower direction.

[0050] 1 to 3, a fuel cell system for a vehicle according to an embodiment of the present invention includes a first cooling line 110 through which a first coolant is circulated through a fuel cell stack 10 of a vehicle, a first cooling unit 60 provided in the first cooling line 110 to cool the first coolant, and a second cooling unit 80 provided in the first cooling line 110 to cool the first coolant separately from the first cooling unit 60.

[0051] For reference, in an embodiment of the present invention, the first cooling line 110 and the second cooling line 120 may constitute a TMS line through which cooling water (first cooling water and second cooling water) can flow while performing heat exchange, and the cooling water may be used as a cooling medium or a heat medium in the TMS line.

[0052] The first cooling line 110 is configured to pass through the fuel cell stack 10 , and the first cooling water circulates along the first cooling line 110 .

[0053] The first cooling line 110 is configured to form a cooling loop for cooling the first coolant or a heating loop for heating (heating) the first coolant depending on the state of the vehicle. As an example, the first cooling line 110 may be configured to form a heating loop for ensuring cold start capability in an initial start state, and to form a cooling loop for discharging heat generated in the fuel cell stack 10 to the outside while the vehicle is running.

[0054] For reference, the fuel cell stack 10 may be formed in a variety of structures capable of producing electricity through an oxidation-reduction reaction of a fuel (eg, hydrogen) and an oxidant (eg, air).

[0055] As an example, the fuel cell stack 10 may include a membrane electrode assembly (MEA) (not shown) having catalytic electrode layers attached to both sides of an electrolyte membrane through which hydrogen ions move, where electrochemical reactions occur; a gas diffusion layer (GDL) (not shown) that uniformly distributes reactant gases and transmits the generated electrical energy; a gasket and fastening mechanism (not shown) for maintaining airtightness and proper fastening pressure between the reactant gases and the first coolant; and a bipolar plate (not shown) for transporting the reactant gases and the first coolant.

[0056] More specifically, in the fuel cell stack 10, hydrogen as a fuel and air (oxygen) as an oxidant are supplied to the anode and cathode of the membrane electrode assembly, respectively, through flow paths in the separator plate, with hydrogen being supplied to the anode and air being supplied to the cathode.

[0057] Hydrogen supplied to the anode is decomposed into hydrogen ions (protons) and electrons by the catalyst in the electrode layers on both sides of the electrolyte membrane, and only the hydrogen ions are selectively transferred to the cathode through the electrolyte membrane, which is a cation exchange membrane, while the electrons are transferred to the cathode through the conductor gas diffusion layer and separator.

[0058] At the cathode, the hydrogen ions supplied through the electrolyte membrane and the electrons transferred through the separator meet with oxygen in the air supplied to the cathode by the air supply device, causing a reaction that produces water. The movement of hydrogen ions causes a flow of electrons through an external conductor, and this flow of electrons generates an electric current.

[0059] The first cooling line 110 is provided with a first cooling section 60 for cooling the first cooling water.

[0060] As the first cooling section 60, various cooling means capable of cooling the first cooling water may be used, and the present invention is not limited or restricted by the type and structure of the first cooling section 60.

[0061] As an example, the first cooling unit 60 may include a first radiator 61 provided in the first cooling line 110 to cool the first coolant.

[0062] The first radiator 61 is installed in the first cooling line 110 to cool the first coolant, and the structure and shape of the first radiator 61 may be variously changed according to required conditions and design specifications.

[0063] Furthermore, a first reservoir 64 for storing a first coolant may be connected to the first radiator 61.

[0064] Further, the first cooling line 110 is provided with a first pump 30 for forcibly flowing the first cooling water.

[0065] As the first pump 30, a conventional pumping means capable of pumping the first cooling water may be used, and the present invention is not limited or restricted by the type and characteristics of the first pump 30.

[0066] 1 and 2, the second cooling part 80 is installed in the first cooling line 110 to cool the first cooling water separately (independently) from the first cooling part 60.

[0067] As the second cooling section 80, various cooling means capable of cooling the first cooling water may be used, and the present invention is not limited or restricted by the type and structure of the second cooling section 80.

[0068] As an example, the second cooling section 80 includes a first branch line 160 branched off from the first cooling line 110, and a second radiator 81 provided in the first branch line 160 so as to be connected in parallel to the first radiator 61, and cooling the first cooling water.

[0069] More specifically, one end of the first branch line 160 is connected to the first cooling line 110 between the outlet of the fuel cell stack 10 and the inlet of the first radiator 61, and the other end of the first branch line 160 is connected to the first cooling line 110 between the outlet of the first radiator 61 and the inlet of the fuel cell stack 10.

[0070] Preferably, the second radiator 81 is configured to be cooled by a second cooling fan 82 that blows outside air.

[0071] In this manner, the embodiment of the present invention has the advantageous effect of ensuring high output of the fuel cell stack 10 and improving safety and reliability by allowing the first cooling water flowing into the fuel cell stack 10 to be cooled separately by the first cooling section 60 and the second cooling section 80.

[0072] In particular, according to an embodiment of the present invention, when a vehicle (e.g., construction machinery) that cannot use wind while traveling is stopped, the temperature of the first cooling water can be lowered using the first cooling section 60 and the second cooling section 80, thereby achieving the advantageous effect of ensuring high-power operation of the fuel cell stack 10 and improving safety and durability.

[0073] Preferably, the first branch line 160 may be provided with a first opening / closing valve 162 that selectively opens and closes the first branch line 160 .

[0074] That is, the first opening / closing valve 162 is provided between the other end of the first branch line 160 and the outlet of the second radiator 81 so as to selectively open and close the first branch line 160 .

[0075] As the first opening / closing valve 162, various valve means capable of selectively opening and closing the first branch line 160 may be used, and the present invention is not limited or restricted by the type and structure of the first opening / closing valve 162.

[0076] As an example, the first opening / closing valve 162 may be a normal two-way valve.

[0077] In a state in which the first opening / closing valve 162 opens the first branch line 160, the first cooling water is cooled via the first radiator 61, and can also be cooled via the second radiator 81. On the other hand, in a state in which the first opening / closing valve 162 blocks the first branch line 160, the first cooling water passes only through the first radiator 61 without passing through the second radiator 81, so that the first cooling water can be cooled only by the first radiator 61.

[0078] For example, in a situation where a high amount of heat dissipation from the fuel cell stack 10 is required (for example, when the fuel cell stack 10 is operating at high power while the vehicle is stopped), the first opening / closing valve 162 can be opened to cool the first cooling water using both the first radiator 61 and the second radiator 81, so that the first cooling water can be cooled more quickly and effectively. On the other hand, when the fuel cell stack 10 is operating at low power, the first opening / closing valve 162 can be shut off and the first cooling water can be cooled only by the first radiator 61.

[0079] According to a preferred embodiment of the present invention, the fuel cell system for a vehicle may include a first pump 30 provided in a first cooling line 110 for pumping the first cooling water, and a flow rate control unit 170 provided in the first cooling line 110 for controlling the flow rate of the first cooling water flowing into the fuel cell stack 10 separately from the first pump 30.

[0080] This is to prevent a decrease in the cooling efficiency of the fuel cell stack 10 due to an insufficient flow rate of the first cooling water.

[0081] In other words, during high-power operation of the fuel cell stack 10, if the flow rate of the first cooling water is smaller than the target flow rate (set flow rate) even if the temperature of the first cooling water is within the appropriate temperature range, there is a problem that the cooling efficiency of the fuel cell stack 10 decreases.

[0082] However, the present invention can obtain the advantageous effect of minimizing the decrease in the flow rate of the first coolant flowing into the fuel cell stack 10 by providing a flow rate control unit 170 that controls the flow rate of the first coolant on the first cooling line 110.

[0083] The flow rate control unit 170 may be provided in various structures capable of controlling the flow rate of the first cooling water, and the present invention is not limited to the structure of the flow rate control unit 170.

[0084] As an example, the flow rate control unit 170 may include a second branch line 172 branching off from the first cooling line 110, and a second pump 174 provided in the second branch line 172 so as to be connected in parallel to the first pump 30 and pumping the first cooling water.

[0085] Preferably, one end of the second branch line 172 is connected to the first cooling line 110 between the outlet of the first radiator 61 and the first pump 30, and the other end of the second branch line 172 is connected to the first cooling line 110 between the first pump 30 and the inlet of the fuel cell stack 10.

[0086] The second pump 174 is provided to forcibly flow the first cooling water passing through the second branch line 172 .

[0087] The second pump 174 may be a conventional pumping means capable of pumping the first cooling water, and the present invention is not limited or restricted by the type and characteristics of the second pump 174.

[0088] Preferably, the second branch line 172 may be provided with a second opening / closing valve 176 that selectively opens and closes the second branch line 172 .

[0089] That is, the second opening / closing valve 176 is provided between the other end of the second branch line 172 and the second pump 174 so as to selectively open and close the second branch line 172 .

[0090] As the second opening / closing valve 176, various valve means capable of selectively opening and closing the second branch line 172 may be used, and the present invention is not limited or restricted by the type and structure of the second opening / closing valve 176.

[0091] As an example, the second opening / closing valve 176 may be a normal two-way valve.

[0092] When the second opening / closing valve 176 opens the second branch line 172, the first cooling water can be pumped by the first pump 30 and the second pump 174. On the other hand, when the second opening / closing valve 176 blocks the second branch line 172, the first cooling water can be pumped only by the first pump 30, and the first cooling water pumped by the first pump 30 can be blocked from flowing into the second pump 174.

[0093] For example, in a situation where a high amount of heat dissipation is required from the fuel cell stack 10 (for example, when the fuel cell stack 10 is operating at high power while the vehicle is parked), the first cooling water can be pumped using both the first pump 30 and the second pump 174 by opening the second opening / closing valve 176, so that a sufficient flow rate of the first cooling water can be guaranteed. On the other hand, when the fuel cell stack 10 is operating at low power, the second opening / closing valve 176 can be shut off and the first cooling water can be pumped only by the first pump 30.

[0094] 1 and 3, according to a preferred embodiment of the present invention, the fuel cell system may include a first connection line 130, which may cooperate with the first cooling line 110 to form a heating loop (heating circulation path) for heating the first cooling water.

[0095] More specifically, one end of the first connection line 130 is connected to the first cooling line 110 at a first point located between the outlet of the first pump 30 and the fuel cell stack 10, and the other end of the first connection line 130 is connected to the first cooling line 110 at a second point located between the inlet of the first pump 30 and the fuel cell stack 10.

[0096] Here, the inlet of the first pump 30 is defined as an inlet through which the first cooling water flows into the first pump 30. Also, the outlet of the first pump 30 is defined as an outlet through which the first cooling water that has passed through the first pump 30 is discharged.

[0097] The section between the outlet of the first pump 30 and the fuel cell stack 10 is defined as a section where the first cooling water discharged from the first pump 30 flows to a first cooling water inlet (not shown) of the fuel cell stack 10. The section between the inlet of the first pump 30 and the fuel cell stack 10 is defined as a section where the first cooling water discharged from a cooling water outlet (not shown) of the fuel cell stack 10 flows to the inlet of the first pump 30.

[0098] According to a preferred embodiment of the present invention, the first connecting line 130 may be provided with a heater 50 , and the first cooling water flowing along the first connecting line 130 may be heated while passing through the heater 50 .

[0099] Further, the first cooling line 110 is provided with a first valve 20 for switching the flow path of the first cooling water to either the heater 50 or the fuel cell stack 10.

[0100] For example, the first valve 20 is provided in the first cooling line 110 so as to be located at a first point, and one end of the first connection line 130 is connected thereto.

[0101] As the first valve 20, various valve means capable of selectively switching the flow path of the first coolant to the heater 50 or the fuel cell stack 10 may be used.

[0102] For example, a typical three-way valve may be used as the first valve 20. More specifically, the first valve 20 includes a first port 21 connected to the first cooling line 110 so that the first cooling water pumped by the first pump 30 flows in, a second port 22 connected to the first cooling line 110 so that the first cooling water passing through the first valve 20 flows into the fuel cell stack 10, and a third port 23 connected to one end of the first connection line 130.

[0103] By opening and closing the second port 22 and the third port 23 of the first valve 20, the flow path of the first coolant can be selectively switched between the heater 50 and the fuel cell stack 10. That is, when the second port 22 is opened and the third port 23 is closed, the first coolant passing through the first valve 20 flows into the fuel cell stack 10. Conversely, when the third port 23 is opened and the second port 22 is closed, the first coolant passing through the first valve 20 flows into the heater 50 via the first connection line 130.

[0104] According to a preferred embodiment of the present invention, the fuel cell system may include a second connection line 150 connected to the first cooling line 110 and forming a heating and cooling loop for heating and cooling the air conditioning unit (HAVC UNIT) 90 in cooperation with the first cooling line 110.

[0105] As an example, the second connection line 150 may form a loop for heating a heater (not shown) of the air conditioning unit 90 .

[0106] More specifically, the second connection line 150 is connected to the first cooling line 110 between a first point (the point where one end of the first connection line 130 is connected to the first cooling line 110) and the outlet of the fuel cell stack 10, and is configured to circulate a portion of the first cooling water.

[0107] Here, the section between the first point and the outlet of the fuel cell stack 10 is defined as a section through which the first cooling water discharged from a cooling water outlet (not shown) of the fuel cell stack 10 flows before passing through the first point.

[0108] As an example, one end of the second connection line 150 is connected to the first cooling line 110 between a first point and the inlet of the fuel cell stack 10, and the other end of the second connection line 150 is connected to the first cooling line 110 between the first pump 30 and a second point.

[0109] In addition, the second connection line 150 may be provided with an ion filter 95 for filtering ions contained in the first coolant that has passed through the air conditioning unit 90 .

[0110] For reference, if the electrical conductivity of the first coolant increases due to corrosion or exudation of the system, electricity will flow through the first coolant, which could cause problems such as short-circuiting the fuel cell stack 10 or current flowing toward the first coolant, so the first coolant must maintain a low electrical conductivity.

[0111] The ion filter 95 is provided to remove ions contained in the first cooling water so that the electrical conductivity of the first cooling water can be maintained at a certain level or lower.

[0112] In this way, the present invention allows the first coolant to circulate along the second connection line 150 as well, thereby enabling filtering (removal of ions contained in the first coolant) by the ion filter 95 provided in the second connection line 150. Therefore, it is possible to obtain an advantageous effect of maintaining the electrical conductivity of the first coolant flowing into the fuel cell stack 10 at a certain level or less.

[0113] In addition, in an embodiment of the present invention, the first cooling line 110 is configured to pass through the first radiator 61 between the first pump 30 and the outlet of the fuel cell stack 10, and may include a third connection line 140 having one end connected to the first cooling line 110 in front of the first radiator 61 and the other end connected to the first cooling line 110 behind the first radiator 61.

[0114] 1 and 3, the third connection line 140 is connected to the first cooling line 110 and is provided to form a cooling loop for cooling the first coolant in cooperation with the first cooling line 110. As an example, one end of the third connection line 140 may be connected to the first cooling line 110 between the first pump 30 and the first radiator 61, and the other end of the third connection line 140 may be connected to the first cooling line 110 between the coolant outlet of the fuel cell stack 10 and the first radiator 61.

[0115] Further, the first cooling line 110 is provided with a second valve 40 for switching the flow path of the first cooling water to either the first radiator 61 or the fuel cell stack 10.

[0116] As an example, the second valve 40 is provided in the first cooling line 110 so as to be located between the first pump 30 and the first radiator 61, and one end of the third connection line 140 and the outlet end (the other end) of the second connection line 150 are connected to it.

[0117] As the second valve 40, various valve means capable of selectively switching the flow path of the first coolant to the first radiator 61 or the fuel cell stack 10 may be used.

[0118] For example, a general four way valve may be used as the second valve 40. More specifically, the second valve 40 includes a first port 41 connected to the third connection line 140, a second port 42 connected to the first cooling line 110 so that the first cooling water passing through the first radiator 61 flows in, a third port 43 connected to the other end of the second connection line 150, and a fourth port 44 connected to the first cooling line 110 so that the first cooling water passing through the second valve 40 flows in to the first pump 30.

[0119] By opening and closing the first port 41 and the second port 42 of the second valve 40, the flow path of the first coolant can be selectively switched between the first radiator 61 or the fuel cell stack 10. That is, when the first port 41 is opened and the second port 42 is closed, the first coolant flows into the fuel cell stack 10 without passing through the first radiator 61. Conversely, when the second port 42 is opened and the first port 41 is closed, the first coolant flows into the fuel cell stack 10 after passing through the first radiator 61.

[0120] Meanwhile, according to a preferred embodiment of the present invention, the fuel cell system may include a first temperature sensor 112 that measures the temperature of the first coolant between the fuel cell stack 10 and a first point (first valve), a second temperature sensor 114 that measures the temperature of the first coolant between the other end of the first connection line 130 and the first pump 30, and a third temperature sensor 116 that measures the temperature of the first coolant at the heater 50, and the inflow flow rate of the first coolant flowing into the fuel cell stack 10 may be controlled based on the temperatures measured by the first temperature sensor 112, the second temperature sensor 114, and the third temperature sensor 116.

[0121] As an example, when the measured temperature of the first cooling water circulating along the first cooling line 110 is lower than a preset target temperature, the inflow flow rate of the first cooling water can be controlled to be lower than a preset set flow rate. In this way, when the measured temperature of the first cooling water is low, the inflow flow rate of the first cooling water flowing into the fuel cell stack 10 can be controlled to be low, thereby obtaining an advantageous effect of minimizing thermal shock and performance degradation due to a temperature deviation of the first cooling water (temperature of the first cooling water stagnating inside the fuel cell stack 10 vs. temperature of the first cooling water flowing into the fuel cell stack 10).

[0122] According to a preferred embodiment of the present invention, the fuel cell system may include a second cooling line 120 arranged to pass through the power electronic parts 200 of the vehicle, and a second cooling water may be circulated along the second cooling line 120.

[0123] Here, the vehicle electrical components 200 may be understood as components that use the vehicle's power source as an energy source, and the present invention is not restricted or limited by the type and number of the vehicle's electrical components 200.

[0124] As an example, the electrical components 200 may include at least one of a BHDC (Bi-directional High voltage DC-DC Converter) 210 provided between the fuel cell stack 10 and a high voltage battery (not shown) of the vehicle, a BPCU (Blower Pump Control Unit) 220 that controls a blower (not shown) that supplies outside air for driving the fuel cell stack 10, a LDC (Low-Voltage DC-DC Converter) 230 that converts a high DC voltage supplied from the high voltage battery to a low DC voltage, an ACP (Air Compressor) 240 that compresses air to be supplied to the fuel cell stack 10, and an air cooler 250.

[0125] The second cooling line 120 is provided with a third pump (not shown) for forcibly flowing the second cooling water.

[0126] As the third pump, a general pumping means capable of pumping the second cooling water may be used, and the present invention is not limited or restricted by the type and characteristics of the third pump.

[0127] Further, the second cooling line 120 may be provided with a third radiator 71 for cooling the second cooling water.

[0128] The third radiator 71 may be formed in various structures capable of cooling the second coolant, and the present invention is not limited or restricted by the type and structure of the third radiator 71.

[0129] Furthermore, a second reservoir 74 in which a second cooling water is stored may be connected to the third radiator 71.

[0130] Preferably, the first radiator 61 and the third radiator 71 are configured to be simultaneously cooled by one first cooling fan 62. As an example, the first radiator 61 and the third radiator 71 are arranged side by side, and the first cooling fan 62 is provided to blow outside air to the first radiator 61 and the third radiator 71.

[0131] In this manner, by allowing the first radiator 61 and the third radiator 71 to be cooled simultaneously by only one first cooling fan 62, the structure can be simplified, and design freedom and space utilization can be improved, and the advantageous effect of minimizing power consumption for cooling the first radiator 61 and the third radiator 71 can be obtained.

[0132] Although the above description focuses on the embodiment, this is merely an example and does not limit the present invention. A person having ordinary knowledge in the field to which the present invention belongs will understand that various modifications and applications not exemplified above are possible within the scope of the essential characteristics of the present embodiment. For example, each component specifically shown in the embodiment can be modified and implemented. Differences related to such modifications and applications should be interpreted as being included in the scope of the present invention defined in the claims.

[0133] As described above, according to the embodiments of the present invention, it is possible to obtain advantageous effects of ensuring high output of a fuel cell stack and improving safety and reliability.

[0134] In particular, according to an embodiment of the present invention, the fuel cell stack can be effectively cooled in situations where high output from the fuel cell stack is required while the vehicle is stopped, thereby achieving the advantageous effect of improving the operating performance and efficiency of the fuel cell stack.

[0135] Also, according to the embodiment of the present invention, it is possible to obtain an advantageous effect of minimizing a decrease in the flow rate of the cooling water flowing into the fuel cell stack, thereby suppressing a decrease in the cooling performance of the fuel cell stack.

Claims

1. a first cooling line through which a first cooling water is circulated through the fuel cell stack of the vehicle; a first cooling section provided in the first cooling line and configured to cool the first cooling water; a second cooling section provided in the first cooling line and configured to cool the first cooling water separately from the first cooling section; a first pump provided in the first cooling line and configured to pump the first cooling water; and a flow rate adjusting unit provided in the first cooling line and configured to adjust a flow rate of the first cooling water flowing into the fuel cell stack separately from the first pump; Including, The first cooling unit is a first radiator provided in the first cooling line and configured to cool the first cooling water; The second cooling section is a first branch line branched from the first cooling line, and a second radiator provided in the first branch line to be connected in parallel with the first radiator and configured to cool the first cooling water; The flow rate adjusting unit is a second branch line branched off from the first cooling line; and a second pump provided in the second branch line to be connected in parallel with the first pump and configured to pump the first cooling water; A fuel cell system for a vehicle.

2. A first cooling line through which a first cooling water is circulated via a fuel cell stack of a vehicle; a first cooling section provided in the first cooling line and configured to cool the first cooling water; and a second cooling section provided in the first cooling line and configured to cool the first cooling water separately from the first cooling section; Including, The first cooling unit is a first radiator provided in the first cooling line and configured to cool the first cooling water; The second cooling section is a first branch line branched from the first cooling line, and a second radiator provided in the first branch line to be connected in parallel with the first radiator and to cool the first cooling water, a first connection line, one end of which is connected to the first cooling line between the outlet of the first radiator and the inlet of the fuel cell stack, and the other end of which is connected to the first cooling line between the outlet of the fuel cell stack and the inlet of the first radiator; a heater provided in the first connecting line and configured to heat the first cooling water flowing along the first connecting line; and a second connection line connected to the first cooling line between the outlet of the first radiator and the inlet of the fuel cell stack via an air conditioning unit of the vehicle, through which the first cooling water circulates; The fuel cell system for a vehicle further comprises:

3. One end of the second branch line is connected to the first cooling line between the outlet of the first radiator and the first pump, 2. The vehicle fuel cell system according to claim 1, wherein the other end of the second branch line is connected to the first cooling line between the first pump and the inlet of the fuel cell stack.

4. 4. The vehicle fuel cell system according to claim 3, further comprising a second opening / closing valve provided in the second branch line between the other end of the second branch line and the second pump.

5. one end of the first branch line is connected to the first cooling line between an outlet of the fuel cell stack and an inlet of the first radiator; 5. The vehicle fuel cell system according to claim 1, wherein the other end of the first branch line is connected to the first cooling line between the outlet of the first radiator and the inlet of the fuel cell stack.

6. 6. The vehicle fuel cell system according to claim 5, further comprising a first opening / closing valve provided in the first branch line between the other end of the first branch line and an outlet of the second radiator.

7. a second cooling line through which a second cooling water is circulated via power electronic parts of the vehicle; and a third radiator provided in the second cooling line and configured to cool the second cooling water; The vehicle fuel cell system according to any one of claims 1 to 4, comprising:

8. 8. The fuel cell system for a vehicle of claim 7, wherein the electrical components include at least one of a bi-directional high voltage DC-DC converter (BHDC) provided between the fuel cell stack and a high voltage battery of the vehicle, a blower pump control unit (BPCU) that controls a blower that supplies outside air for driving the fuel cell stack, a low-voltage DC-DC converter (LDC) that converts a high DC voltage supplied from the high voltage battery to a low DC voltage, an air compressor (ACP) that compresses air supplied to the fuel cell stack, and an air cooler.

9. The first radiator and the third radiator are arranged side by side, 8. The fuel cell system for a vehicle according to claim 7, further comprising a first cooling fan that blows outside air to the first radiator and the third radiator.

10. 5. The vehicle fuel cell system according to claim 1, further comprising a second cooling fan that blows outside air to the second radiator.

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