KR102506850B1 - Fuel cell symtem - Google Patents

Abstract

The present invention relates to a fuel cell system, which includes a fuel cell stack, a cooling water line having a radiator, and through which cooling water is circulated; A vortex tube capable of separating compressed air into hot air and cold air; a hot air supply unit capable of selectively supplying the hot air to the radiator; and a control unit capable of controlling the hot air supply unit.

Description

Fuel cell system {FUEL CELL SYMTEM}

The present invention relates to a fuel cell system.

A fuel cell is a kind of power generation device that converts the chemical energy of fuel into electrical energy by electrochemically reacting it in a fuel cell stack without converting it into heat by combustion. It can also be applied to power supply of electrical/electronic products, especially portable devices.

As an example of a fuel cell, a polymer electrolyte membrane fuel cell (PEMFC: Polymer Electrolyte Membrane Fuel Cell, Proton Exchange Membrane Fuel Cell), which is the most studied as a power supply source for driving vehicles, is a polymer electrolyte membrane in which hydrogen ions move. Membrane Electrode Assembly (MEA) with catalyst electrode layers where electrochemical reactions occur on both sides, Gas Diffusion Layer (GDL) that evenly distributes reactive gases and transmits the generated electrical energy, It is configured to include a gasket and a fastening mechanism for maintaining airtightness and proper clamping pressure of the reactive gases and cooling water, and a bipolar plate for moving the reactive gases and cooling water.

In the fuel cell described above, hydrogen as a fuel and oxygen (air) as an oxidizing agent are supplied to the anode and cathode of the membrane electrode assembly through the flow path of the separator, respectively. is supplied to the cathode (also referred to as 'anode' or 'oxidation electrode'), and oxygen (air) is supplied to the cathode (also referred to as 'air electrode' or 'oxygen electrode' or 'reduction electrode').

Hydrogen supplied to the anode is decomposed into hydrogen ions (proton, H+) and electrons (e-) by the catalysts of the electrode layers formed on both sides of the electrolyte membrane. Of these, only hydrogen ions selectively pass through the electrolyte membrane, a cation exchange membrane, At the same time, electrons are transferred to the cathode through the gas diffusion layer and the separator, which are conductors.

In the cathode, hydrogen ions supplied through the electrolyte membrane and electrons transferred through the separator meet oxygen in the air supplied to the cathode by the air supply device to cause a reaction to generate water. At this time, due to the movement of hydrogen ions, a flow of electrons occurs through the external conductor, and current is generated by the flow of these electrons.

On the other hand, a fuel cell system mounted in a vehicle largely includes a fuel cell stack generating electrical energy, a fuel supply device supplying fuel (hydrogen) to the fuel cell stack, and oxygen in the air, an oxidizing agent required for an electrochemical reaction, to the fuel cell stack. It consists of an air supply device that supplies, a thermal management system (TMS: Thermal Management System) that removes the reaction heat of the fuel cell stack to the outside of the system and controls the operating temperature of the fuel cell stack.

With this configuration, in the fuel cell system, electricity is generated by an electrochemical reaction between hydrogen as a fuel and oxygen in the air, and heat and water are discharged as reaction by-products.

Since the above fuel cell system generates heat as a reaction by-product, a cooling device for cooling the stack is essential to prevent the temperature of the stack from rising. In addition, since the most urgent and difficult problem in the fuel cell system is the strategy to secure cold startability, the role of the thermal management system can be said to be more important than anything else.

As is well known, the coolant in the TMS line serves as a refrigerant for cooling the stack and serves as a heat source for thawing the stack by being heated by a heater and supplied to the stack during cold startup. However, it is difficult to rapidly heat the cooling water within a short time only by heating the cooling water using a heater. Therefore, the conventional fuel cell system has a problem in that a long time is required for cold starting, and driver's convenience is deteriorated.

SUMMARY OF THE INVENTION The present invention is to solve the problems of the prior art described above, and an object of the present invention is to provide a fuel cell system having an improved structure so as to reduce the time required for cold start.

Furthermore, an object of the present invention is to provide a fuel cell system having an improved structure to prevent damage to a humidifier or a stack due to high-temperature outside air.

A fuel cell system according to a preferred embodiment of the present invention for solving the above problems includes a fuel cell stack, a radiator, and a cooling water line through which cooling water is circulated; A vortex tube capable of separating compressed air into hot air and cold air; a hot air supply unit capable of selectively supplying the hot air to the radiator; and a control unit capable of controlling the hot air supply unit.

Preferably, the control unit controls the hot air supply unit to supply the hot air to the radiator when the vehicle is cold started in a state where the temperature of the coolant is equal to or less than a predetermined cold start temperature.

Preferably, the cooling water line further includes a cooling water heater, and the control unit is configured to heat the cooling water when the vehicle is cold-started below in a state where the temperature of the cooling water is at the cold start temperature. control the heater

Preferably, the control unit controls the coolant heater to heat the coolant when the battery SOC is equal to or greater than a predetermined target SOC when the vehicle is cold-started in a state where the temperature of the coolant is equal to or less than the cold start temperature.

Preferably, the hot air supply unit is installed on a hot air supply line connecting the radiator and the vortex tube to supply the hot air to the radiator, and the hot air supply line, the hot air supply line A high-temperature air control valve capable of opening and closing is further provided.

Preferably, the hot air control valve is composed of a three-way valve capable of selectively guiding the hot air to the radiator or the outside.

Preferably, it further includes a low-temperature air supply unit capable of selectively supplying the low-temperature air to the stack.

Preferably, the control unit controls the low-temperature air supply unit to supply the low-temperature air to the stack when the vehicle is driven in a state where the temperature of the cooling water is equal to or higher than a predetermined limit temperature.

Preferably, the low-temperature air supply unit is installed on a low-temperature air supply line connecting the stack and the vortex tube so as to supply the low-temperature air to the stack, and the low-temperature air supply line, the low-temperature air supply line A low-temperature air control valve capable of opening and closing is further provided.

Preferably, the low-temperature air control valve is composed of a three-way valve capable of selectively guiding the low-temperature air to the stack or to the outside.

Preferably, a humidifier is installed between the stack and the low-temperature air supply unit, and is capable of humidifying the low-temperature air supplied by the low-temperature air supply unit and delivering the humidifier to the stack.

Preferably, the humidifier is composed of a hollow fiber membrane humidifier capable of humidifying the low-temperature air by exchanging moisture between the wet air discharged from the stack and the low-temperature air.

Preferably, the coolant line further includes a coolant heater, and the control unit controls the coolant heater to heat the coolant by using regenerative braking energy recovered during braking of the vehicle, and simultaneously blows the low-temperature air into the stack. The low-temperature air supply unit is controlled to supply.

Preferably, the vortex tube includes a hot air outlet through which the hot air is discharged and a low temperature air outlet through which the low temperature air is discharged, and the hot air supply unit includes a hot air supply control valve capable of opening and closing the hot air outlet. wherein the control unit controls the high-temperature air control valve to discharge the compressed air from the low-temperature air by closing the high-temperature air outlet when the vehicle is driven in a state where the temperature of the coolant is at a predetermined normal temperature. and controls the low-temperature air supply unit to supply the compressed air discharged from the low-temperature air outlet to the stack.

The fuel cell system according to the present invention has the following effects.

First, according to the present invention, the cooling water passing through the radiator is heated using the high-temperature air discharged from the vortex tube, thereby reducing the time required for a cold start and improving the driver's convenience.

Second, the present invention can improve the durability of the fuel cell system by preventing the humidifier and the stack from being damaged by high temperatures by cooling the humidifier and the stack using low-temperature air discharged from the vortex tube.

Thirdly, in the present invention, when the regenerative braking energy is consumed using the coolant heater, the humidifier and the stack are cooled using the low-temperature air discharged from the vortex tube, so that the temperature of the humidifier and the stack is reduced due to the consumption of the regenerative braking energy using the coolant heater. rise can be prevented.

1 is a diagram showing a schematic configuration of a fuel cell system according to a preferred embodiment of the present invention;
FIG. 2 is a view showing how the vortex tube shown in FIG. 1 separates compressed air into high-temperature air and low-temperature air.
3 is a view for explaining a method of driving the fuel cell system shown in FIG. 1 in a cold start mode;
FIG. 4 is a view for explaining a method of driving the fuel cell system shown in FIG. 1 in a normal mode;
5 is a view showing an aspect in which the vortex tube shown in FIG. 1 discharges compressed air as it is;
6 is a view for explaining a method of driving the fuel cell system shown in FIG. 1 in a high power mode;
7 is a view for explaining a method of driving the fuel cell system shown in FIG. 1 in a regenerative braking mode;

Terms or words used in this specification and claims should not be construed as being limited to ordinary or dictionary meanings, and the inventor may appropriately define the concept of terms in order to explain his or her invention in the best way. It should be interpreted as a meaning and concept consistent with the technical idea of the present invention based on the principle that there is. Therefore, since the embodiments described in this specification and the configurations shown in the drawings are only one of the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention, various alternatives can be made at the time of this application. It should be understood that there may be equivalents and variations.

In the drawings, the size of each component or a specific part constituting the component is exaggerated, omitted, or schematically illustrated for convenience and clarity of explanation. Therefore, the size of each component does not fully reflect the actual size. If it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the gist of the present invention, such description will be omitted.

1 is a diagram showing the schematic configuration of a fuel cell system according to a preferred embodiment of the present invention, and FIG. 2 is a diagram showing how the vortex tube shown in FIG. 1 separates compressed air into high-temperature air and low-temperature air. .

Referring to FIG. 1 , a fuel cell system (hereinafter referred to as 'fuel cell system 1') according to a preferred embodiment of the present invention includes a cooling water line 10, a compressed air supply unit 20, and a vortex. It may include a tube 30, a hot air supply unit 40, a low temperature air supply unit 50, a humidifier 60, a control unit 70, and the like.

First, as shown in FIG. 1 , the cooling water line 10 includes a cooling water pump 80, a fuel cell stack (hereinafter referred to as 'stack 90'), a radiator 100, and a cooling water heater ( 110), cooling water temperature sensors 12 and 14, and the like. The coolant line 10 is provided so that the coolant C can circulate through the coolant pump 80 , the stack 90 , the radiator 100 , and the coolant heater 110 .

The cooling water pump 80 pumps the cooling water C to provide the cooling water C with a driving force for circulating the cooling water line 10 .

The stack 90 is provided to generate electricity using hydrogen supplied from a hydrogen supply unit (not shown) and air supplied from the low-temperature air supply unit 50 . The stack 90 may be heated or cooled by the cooling water C circulating through the cooling water line 10 .

The radiator 100 is provided to allow heat exchange between the cooling water C passing through the cooling water line 10 and the outside air passing through the outer surface of the radiator 100 . For example, when the temperature of the outside air is lower than that of the cooling water (C), the radiator 100 may cool the cooling water (C) by exchanging heat with the cooling water (C) and the outside air. For example, when the temperature of the outside air is higher than that of the cooling water C, the radiator 100 may heat the cooling water C by exchanging heat with the cold water and the outside air.

The cooling water heater 110 is provided to heat the cooling water C circulating through the cooling water line 10 using electricity supplied from the stack 90 or an external electricity supply device. The cooling water heater 110 is preferably composed of a COD integrated heater capable of consuming electrical energy generated using the residual hydrogen and residual oxygen of the stack 90 as thermal energy when the stack 90 is stopped or started, It is not limited to this.

The cooling water temperature sensors 12 and 14 may be installed at predetermined positions in the cooling water line 10 to measure the temperature of the cooling water C. For example, the coolant temperature sensors 12 and 14, as shown in FIG. 1 , measure the temperature of the coolant C flowing into the stack 90 and the temperature of the coolant C discharged from the stack 90. Each may be installed upstream and downstream of the stack 90 so as to be measurable.

Next, as shown in FIG. 1 , the compressed air supply unit 20 may include an air compressor 120 and a compressed air supply line 130 .

The air compressor 120 may suck in outside air A1 and compress it to a predetermined pressure, and then discharge the compressed air P that has been compressed in this way.

As shown in FIG. 1 , the compressed air supply line 130 connects the air compressor 120 and the compressed air inlet 32 of the vortex tube 30 to be described later. The compressed air supply line 130 may supply the compressed air P compressed by the air compressor 120 to the vortex tube 30 .

Next, the vortex tube 30 converts the kinetic energy of the compressed air P into thermal energy so that the compressed air P can be thermally separated into high-temperature air H and low-temperature air L. As shown in FIG. 2, the vortex tube 30 may include a compressed air inlet 32, a vortex rotation chamber 34, a hot air outlet 36, and a cold air outlet 38. .

The compressed air inlet 32 introduces the compressed air P passed through the compressed air supply line 130 into the vortex rotation chamber 34 . The vortex rotation chamber 34 converts the kinetic energy of the compressed air P into thermal energy and thermally separates the compressed air P into high temperature air H and low temperature air L. The hot air discharge port 36 discharges the hot air H, and the discharged hot air H is introduced into the hot air supply line 140 of the hot air supply unit 40 to be described later. The low-temperature air discharge port 38 discharges the low-temperature air L, and the discharged low-temperature warm air flows into the low-temperature air supply line 170 of the low-temperature air supply unit 50 to be described later.

Since this vortex tube 30 is made of a vortex tube of a conventional structure that converts the kinetic energy of a predetermined fluid into thermal energy in the art and separates the predetermined fluid into a high-temperature fluid and a low-temperature fluid, a detailed description of the configuration is omitted. I'm going to do it.

Next, the hot air supply unit 40 is provided to selectively supply the hot air H discharged from the hot air outlet 36 of the vortex tube 30 to the radiator 100 . As shown in FIG. 1 , the hot air supply unit 40 may include a hot air supply line 140 and a hot air control valve 150 .

The hot air supply line 140 connects the hot air outlet 36 and the radiator 100 so that the hot air H discharged from the hot air outlet 36 of the vortex tube 30 can be supplied to the radiator 100. do. For example, the hot air supply line 140 may be provided to spray the hot air H discharged from the hot air outlet 36 of the vortex tube 30 to the outer surface of the radiator 100. .

The hot air supply line 140 may include a first section 142 and a second section 144 . The first section 142 connects the hot air outlet 36 and the first port 152 of the hot air control valve 150 . The second section 144 connects the second port 154 of the high-temperature air control valve 150 and the radiator 100 . In particular, the second section 144 is preferably provided so that the hot air H passing through the second port 154 of the hot air control valve 150 can be sprayed to the outer surface of the radiator 100. It is not limited. Accordingly, the high-temperature air H may pass through the first section 142 and the second section 144 sequentially and be supplied to the radiator 100 .

The hot air control valve 150 is installed on the hot air supply line 140 to be able to open and close the hot air supply line 140 . The type of hot air control valve 150 is not particularly limited. For example, the hot air control valve 150 may be composed of a three-way valve capable of selectively guiding the hot air H discharged from the hot air outlet 36 of the vortex tube 30 to the radiator 100 or the outside. can As shown in FIG. 1, the hot air control valve 150 includes a first port 152 connected to the first section 142 and a second port 154 connected to the second section 144. , a third port 156 connected to the hot air discharge line 160 may be provided. The hot air control valve 150 selectively opens and closes the ports to supply the hot air H to the radiator 100 through the second section 144 or discharge it to the outside through the hot air discharge line 160. can do.

Next, the low-temperature air supply unit 50 is provided to selectively supply the low-temperature air L discharged from the low-temperature air outlet 38 of the vortex tube 30 to the stack 90 . As shown in FIG. 1 , the low-temperature air supply unit 50 may include a low-temperature air supply line 170 and a low-temperature air control valve 180 .

The low-temperature air supply line 170 connects the low-temperature air outlet 38 and the stack 90 so that the low-temperature air L discharged from the low-temperature air outlet 38 of the vortex tube 30 can be supplied to the stack 90. do. As shown in FIG. 1 , the low-temperature air supply line 170 may include a first section 172, a second section 174, a third section 176, and the like. The first section 172 connects the cold air outlet 38 and the first port 182 of the cold air control valve 180 . The second section 144 connects the second port 184 of the cold air control valve 180 to the cold air inlet 62 of the humidifier 60 . The third section 176 connects the cold air outlet 38 of the humidifier 60 and the cold air inlet 92 of the stack 90 . Accordingly, the low-temperature air L may be supplied to the stack 90 by sequentially passing through the first section 172, the second section 174, the humidifier 60, and the third section 176. Meanwhile, as shown in FIG. 1 , the third section 176 may include an air temperature sensor 178 capable of measuring the temperature of air passing through the third low-temperature air supply line 176 .

The low-temperature air control valve 180 is installed on the low-temperature air supply line 170 to be able to open and close the low-temperature air supply line 170 . The type of low-temperature air control valve 180 is not particularly limited. For example, the low-temperature air control valve 180 may be composed of a three-way valve capable of selectively guiding the low-temperature air L discharged from the low-temperature air outlet 38 of the vortex tube 30 to the stack 90 or to the outside. can As shown in FIG. 1, the low-temperature air control valve 180 includes a first port 182 connected to the first section 172 and a second port 184 connected to the second section 174. , a third port 186 connected to the low-temperature air discharge line 190 may be provided. The low-temperature air control valve 180 selectively opens and closes ports to supply low-temperature air L to the stack 90 through the second section 174 and the third section 156 or the low-temperature air discharge line 190 ) can be discharged to the outside.

Next, the humidifier 60 is provided to humidify the low-temperature air L and supply it to the stack 90 . For example, the humidifier 60 may be configured as a hollow fiber membrane humidifier capable of exchanging moisture between the wet air A2 discharged from the stack 90 and the low-temperature air L and supplying the stack 90 with moisture. Here, the wet air A2 refers to air discharged to the stack 90 in a state of being humidified by the product water generated in the stack 90 . The humidifier 60 may include a cold air inlet 62 , a cold air outlet 64 , a wet air inlet 66 , a wet air outlet 68 , and the like.

The cold air inlet 62 is connected to the second port 184 of the cold air control valve 180 by the second section 174 . The cold air outlet 64 is connected to the cold air inlet 62 of the stack 90 through a third section 176 . The wet air inlet 66 is connected to the wet air outlet 94 of the stack 90 by the first section 202 of the wet air outlet line 200 . The wet air outlet 68 is connected to the outside by a second section 204 of the wet air outlet line 200 . The humidifier 60 may humidify the low-temperature air L by exchanging moisture between the low-temperature air L introduced through the low-temperature air inlet 62 and the wet air A2 introduced through the wet air inlet 66. there is. The low-temperature air L is supplied to the stack 90 through the third section 176, and the stack 90 may generate electricity using the supplied low-temperature air L. Also, the wet air A2 may be discharged to the outside through the second section 204 .

Next, the control unit 70 is provided to be able to control various components included in the fuel cell system 1 . The control unit 70 may drive the vehicle applied to the fuel cell system 1 according to predetermined driving modes such as a cold start mode, a normal mode, a high power mode, and a regenerative braking mode.

FIG. 3 is a diagram for explaining a method of driving a vehicle to which the fuel cell system shown in FIG. 1 is applied in a cold start mode.

The control unit 70 controls the hot air supply unit 40 to supply the hot air H to the radiator 100 as shown in FIG. 3 when the vehicle is driven in the cold start mode; At the same time, the cooling water heater 110 may be controlled to heat the cooling water (C). The cold start mode refers to a mode in which the vehicle is started in a state where the temperature of the coolant C is equal to or less than a predetermined cold start temperature. For example, the cold start temperature may be -30 °C.

The control unit 70 opens the first port 152 and the second port 154 of the hot air control valve 150 and closes the third port 156 at the same time. Then, as shown in FIG. 3 , the high-temperature air H is supplied to the radiator 100, and the cooling water C passing through the radiator 100 is heated by exchanging heat with the high-temperature air H.

The control unit 70 operates the cooling water heater 110 using electric energy supplied from a battery (not shown). Then, the cooling water (C) heated by the hot air (H) is reheated by the cooling water heater (110). That is, the cooling water (C) is heated secondarily by the hot air (H) and the cooling water heater (110). Therefore, since the coolant C can be heated faster than when the coolant C is heated using only the coolant heater 110, the driver's convenience can be improved by reducing the time required for cold start.

However, it is preferable that the battery is managed such that the battery SOC (State Of Charge) is higher than a predetermined target SOC. Accordingly, the control unit 70 preferably operates the coolant heater 110 selectively only when the battery SOC is higher than a predetermined target SOC. That is, when the SOC of the battery is lower than the target SOC, the cold start is performed by heating the coolant (C) using only the hot air (H).

Meanwhile, the control unit 70 preferably controls the low-temperature air supply unit 50 so that the low-temperature air L is discharged to the outside.

Specifically, the control unit 70 opens the first port 182 and the third port 186 of the low-temperature air supply valve 180 and simultaneously closes the second port 184 . Then, as shown in FIG. 3 , the low-temperature air L is discharged to the outside through the low-temperature air discharge line 190 .

FIG. 4 is a view for explaining a method of driving a vehicle to which the fuel cell system shown in FIG. 1 is applied in a normal mode, and FIG. 5 is a view showing how the vortex tube shown in FIG. 1 discharges compressed air as it is. .

The control unit 70 includes the low-temperature air supply unit 50 and the high-temperature air supply unit to supply the compressed air P to the stack 90, as shown in FIG. 4 when the vehicle is driven in the normal mode. (40) can be controlled. The normal mode refers to a mode in which the vehicle is driven in a state where the temperature of the coolant C is at a predetermined normal temperature after the engine is started.

Referring to FIG. 5, when the hot air outlet 36 of the vortex tube 30 is closed, the compressed air P is separated into hot air H and low temperature air L in the vortex rotation chamber 34. It can be discharged as it is through the low-temperature air discharge port 38.

Reflecting this, the control unit 70 closes the first port 152 of the high temperature air control valve 150 and closes the first port 182 and the second port 184 of the low temperature air control valve 180. At the same time as opening the third port 186 is closed. Then, as shown in FIG. 4 , the compressed air P is discharged as it is through the low-temperature air outlet 38 without being thermally separated by the vortex tube 30 and supplied to the stack 90 . Through this, it is possible to prevent the stack 90 from being cooled below normal temperature by the low-temperature air L.

FIG. 6 is a diagram for explaining a method of driving a vehicle to which the fuel cell system shown in FIG. 1 is applied in a high power mode.

The control unit 70 may control the low-temperature air supply unit 50 to supply the low-temperature air L to the stack 90 as shown in FIG. 6 when the vehicle is driven in the high power mode. . The high power mode refers to a mode in which the vehicle is operated so that the output of the stack 90 exceeds a predetermined reference power. In general, the temperature of the stack 90 and the temperature of the humidifier 60 to which the wet air A discharged from the stack 90 is supplied rises or falls in proportion to the output of the stack 90 . Therefore, when the output of the stack 90 is greater than or equal to the reference output, the stack 90 and the humidifier 60 have a relatively high temperature corresponding to the output of the stack 90 .

The control unit 70 opens the first port 182 and the second port 184 of the low-temperature air control valve 180 and closes the third port 186 at the same time. Then, as shown in FIG. 6, the low-temperature air L is supplied to the stack 90 via the humidifier 60, and the humidifier 60 and the stack 90 are cooled by the low-temperature air L . Through this, it is possible to improve durability of the fuel cell stack 90 by preventing the humidifier 60 and the stack 90 from being damaged by high temperatures.

Meanwhile, the control unit 70 preferably controls the hot air supply unit 40 so that the hot air H is discharged to the outside.

Specifically, the control unit 70 closes the second port 154 while opening the first port 152 and the third port 186 of the hot air supply valve. Then, as shown in FIG. 6 , the hot air H is discharged to the outside through the hot air discharge line 160 .

In addition, the control unit 70 supplies compressed air P to the stack 10 until the temperature of the cooling water T reaches a predetermined limit temperature, as in the case of the normal mode, and coolant T It is preferable to supply low-temperature air (L) to the stack 10 as a ratio after the temperature of reaches the limit temperature, but is not limited thereto. For example, the limiting temperature may be 80 °C.

FIG. 7 is a diagram for explaining a method of driving a vehicle to which the fuel cell system shown in FIG. 1 is applied in a regenerative braking mode.

When the vehicle is driven in the regenerative braking mode, the control unit 70 controls the coolant heater 110 to heat the coolant C by using the regenerative braking energy recovered when the vehicle is braked, and simultaneously controls the low-temperature air (L ) is controlled to supply the low-temperature air supply unit 50 to the stack 90. Here, the regenerative braking mode refers to a mode in which the vehicle is driven so that regenerative braking energy recovered during braking of the vehicle can be consumed using the fuel cell system 1 .

Specifically, the control unit 70 drives the coolant heater 110 using regenerative braking energy, opens the first port 182 and the second port 184 of the low-temperature air control valve 180, and simultaneously The third port 186 is closed. Then, the cooling water heater 110 heats the cooling water C, and the low-temperature air L is supplied to the stack 90 via the humidifier 60 to cool the humidifier 60 and the stack 90. That is, the heating of the cooling water (C) by the regenerative braking energy is compensated by the cooling of the stack (90) by the low-temperature air (L). Through this, it is possible to improve durability of the fuel cell system 1 by preventing the stack 90 from being heated due to regenerative braking energy.

Meanwhile, the control unit 70 preferably controls the hot air supply unit 40 so that the hot air H is discharged to the outside.

Specifically, the control unit 70 closes the second port 154 while opening the first port 152 and the third port 186 of the hot air supply valve. Then, as shown in FIG. 7 , the hot air H is discharged to the outside through the hot air discharge line 160 .

In addition, the control unit 70 operates the coolant heater 110 using regenerative braking energy only when the battery is fully charged and the regenerative braking energy cannot be charged into the battery, and at the same time, the low-temperature air (L) is supplied to the stack 10. It is preferable to supply, but is not limited thereto.

In addition, the control unit 70 supplies compressed air P to the stack 10 until the temperature of the cooling water T reaches the limit temperature, as in the case of the normal mode, and It is preferable to supply low-temperature air (L) to the stack 10 as a ratio after the temperature reaches the limit temperature, but is not limited thereto.

Although the present invention has been described above with limited examples and drawings, the present invention is not limited thereto and will be described below and the technical spirit of the present invention by those skilled in the art to which the present invention belongs. Of course, various modifications and variations are possible within the scope of the claims.

1: fuel cell system
10: coolant line
12, 14: coolant temperature sensor
20: compressed air supply unit
30: vortex tube
32: compressed air inlet
34: vortex rotation chamber
36: hot air outlet
38: low temperature air outlet
40: hot air supply unit
50: low temperature air supply unit
60: Humidifier
62: low temperature air inlet
64: low temperature air outlet
66: wet air inlet
68: wet air outlet
70: control unit
80: cooling water pump
90: stack
92: low temperature air inlet
94: low temperature air outlet
100: radiator
110: coolant heater
120: air compressor
130: compressed air supply line
140: hot air supply line
150: hot air control valve
160: hot air discharge line
170: low temperature air supply line
178: low temperature air temperature sensor
180: low temperature air control valve
190: low temperature air discharge line
200: wet air discharge line
A1: outside air
P: compressed air
C: coolant
H: hot air
L: cold air
A2: moist air

Claims (14)

a cooling water line including a fuel cell stack and a radiator, through which cooling water is circulated;
A vortex tube capable of separating compressed air into hot air and cold air;
a high-temperature air supply line connecting the radiator and the vortex tube to supply the high-temperature air to the radiator; and a high-temperature air control valve installed on the hot air supply line and capable of opening and closing the hot air supply line. air supply unit;
a hot air discharge line connected to the hot air control valve and discharging the hot air to the outside in a state in which the supply of the hot air to the radiator is blocked; and
and a control unit capable of controlling the hot air supply unit. According to claim 1,
The fuel cell system of claim 1 , wherein the control unit controls the hot air supply unit to supply the hot air to the radiator when the vehicle is cold started at a temperature of the coolant below a predetermined cold start temperature. According to claim 2,
The cooling water line further includes a cooling water heater,
The fuel cell system of claim 1 , wherein the control unit controls the cooling water heater to heat the cooling water when the vehicle is cold-started in a state where the temperature of the cooling water is equal to or less than the cold-starting temperature. According to claim 3,
The control unit controls the coolant heater to heat the coolant when the battery SOC is equal to or greater than a predetermined target SOC when the vehicle is cold-started in a state where the temperature of the coolant is equal to or less than the cold start temperature. fuel cell system. delete According to claim 1,
The fuel cell system according to claim 1 , wherein the hot air control valve is composed of a three-way valve capable of selectively guiding the hot air to the radiator or the outside. According to claim 1,
and a low-temperature air supply unit capable of selectively supplying the low-temperature air to the stack. According to claim 7,
The fuel cell system of claim 1 , wherein the control unit controls the low-temperature air supply unit to supply the low-temperature air to the stack when the vehicle is driven in a state where the temperature of the cooling water is equal to or higher than a predetermined limit temperature. According to claim 7,
The low-temperature air supply unit is installed on a low-temperature air supply line connecting the stack and the vortex tube to supply the low-temperature air to the stack, and the low-temperature air supply line, and is capable of opening and closing the low-temperature air supply line. A fuel cell system further comprising a low-temperature air control valve. According to claim 9,
The fuel cell system according to claim 1 , wherein the low-temperature air control valve is composed of a three-way valve capable of selectively guiding the low-temperature air to the stack or to the outside. According to claim 7,
The fuel cell system of claim 1, further comprising a humidifier installed between the stack and the low-temperature air supply unit and capable of humidifying the low-temperature air supplied by the low-temperature air supply unit and delivering the humidifier to the stack. According to claim 11,
The fuel cell system of claim 1 , wherein the humidifier is composed of a hollow fiber membrane humidifier capable of humidifying the low-temperature air by exchanging water between the wet air discharged from the stack and the low-temperature air. According to claim 7,
The cooling water line further includes a cooling water heater,
The control unit controls the coolant heater to heat the coolant by using regenerative braking energy recovered during braking of the vehicle and simultaneously controls the low-temperature air supply unit to supply the low-temperature air to the stack. fuel cell system. According to claim 7,
The vortex tube includes a hot air outlet through which the high-temperature air is discharged and a low-temperature air outlet through which the low-temperature air is discharged,
The hot air supply unit includes a hot air supply control valve capable of opening and closing the hot air outlet,
The control unit controls the hot air control valve so that the hot air outlet is closed and the compressed air is discharged from the low temperature air when the vehicle is driven in a state where the temperature of the coolant is at a predetermined normal temperature. and controlling the low-temperature air supply unit to simultaneously supply compressed air discharged from the low-temperature air outlet to the stack.

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