Fuel cell system and method of operating a fuel cell system

Abstract

To ensure high output of a fuel cell stack and improve safety and durability of a fuel cell.SOLUTION: A fuel cell system includes a sensor unit 510 that is set to measure a temperature of cooling water at an inlet of a fuel cell and an outside-air temperature, a cooling fan 530 that cools cooling water, and a cooling fan control unit 520 connected with the sensor unit 510 and the cooling fan 530. The cooling fan control unit 520 is set to determine revolving speed of the cooling fan 530 on the basis of the outside-air temperature and an output value of the fuel cell and correct the revolving speed of the cooling fan 530 on the basis of the temperature of cooling water at the inlet of the fuel cell.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a fuel cell system and a method of operating a fuel cell system. [Background technology]

[0002] A fuel cell system can generate electrical energy using a fuel cell stack. For example, when hydrogen is used as a fuel for a fuel cell stack, it can be an alternative solution to global environmental issues, and research and development into fuel cell systems is ongoing. 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 reaction heat from the fuel cell stack to the outside of the system, controls the operating temperature of the fuel cell stack, and performs water management functions.

[0003] The thermal management system is a type of cooling device that circulates antifreeze, which acts as coolant, through the fuel cell stack to maintain an appropriate temperature (e.g., 60 to 70°C), and can include a TMS line through which the coolant 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 the heat of the coolant to the outside. The thermal management system can also include a heater that heats the coolant and an air conditioning unit (e.g., a space heater) that uses the coolant to heat or cool the interior of a device (e.g., a vehicle) that includes the fuel cell system. The thermal management system can maintain appropriate temperatures not only for the fuel cell stack but also for the vehicle's electrical components. Summary of the Invention [Problem to be solved by the invention]

[0004] Recently, various attempts have been made to apply fuel cell systems not only to passenger cars (or commercial vehicles) but also to construction machinery. In the case of passenger cars, fuel cell systems can cool the fuel cell stack using a cooling fan while the vehicle is stopped, and while the vehicle is moving, the fuel cell stack can be cooled using the wind generated by the vehicle's speed. However, construction machinery performs tasks that require high power output even when the vehicle is stopped (e.g., leveling and loading), so the amount of wind generated by the cooling fan may not be enough to cool the coolant, which can reduce the safety and durability of the fuel cell stack. [Means for solving the problem]

[0005] A fuel cell system according to one embodiment disclosed in this specification includes a sensor unit configured to measure the temperature of the cooling water at the inlet of the fuel cell and the outside air temperature, a cooling fan that cools the cooling water, and a cooling fan control unit connected to the sensor unit and the cooling fan, and the cooling fan control unit can be configured to determine the rotation speed of the cooling fan based on the outside air temperature and the output value of the fuel cell, and to correct the rotation speed of the cooling fan based on the temperature of the cooling water at the inlet of the fuel cell.

[0006] A method of operating a fuel cell system according to one embodiment disclosed in this specification may include the operations of measuring the temperature of the cooling water at the inlet of the fuel cell, measuring the outside air temperature, determining the rotation speed of the cooling fan based on the outside air temperature and the output value of the fuel cell, and correcting the rotation speed of the cooling fan based on the temperature of the cooling water at the inlet of the fuel cell. [Effects of the Invention]

[0007] According to the embodiments disclosed herein, the fuel cell system can ensure high output of the fuel cell stack and improve the safety and durability of the fuel cell.

[0008] According to the embodiments disclosed herein, the fuel cell system can improve the safety and durability of the fuel cell by improving the cooling performance even when the vehicle is stopped.

[0009] According to the embodiments disclosed in this specification, the fuel cell system can prevent a decrease in cooling performance due to the heat load of electrical components.

[0010] In addition, various other effects can be provided that are directly or indirectly grasped by this specification. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 illustrates a fuel cell system according to various embodiments. [Figure 2] FIG. 1 illustrates a fuel cell system according to various embodiments. [Figure 3] FIG. 1 illustrates another example of a fuel cell system according to various embodiments. [Figure 4] FIG. 1 illustrates another example of a fuel cell system according to various embodiments. [Figure 5] FIG. 1 is a block diagram of a fuel cell system for controlling a cooling fan according to various embodiments. [Figure 6] 1 is a flowchart of operations for controlling a cooling fan according to various embodiments. [Figure 7] 10 is a flowchart of operations for determining the rotation speed of a cooling fan according to various embodiments. [Figure 8] 10 is a flowchart of an operation for correcting the rotation speed of a cooling fan according to various embodiments.

[0012] In connection with the description of the drawings, the same or similar reference numerals may be used for the same or similar components. DETAILED DESCRIPTION OF THE INVENTION

[0013] Various embodiments of the present invention will now be described with reference to the accompanying drawings, but it should be understood that this is not intended to limit the invention to the particular embodiments, but rather to include various modifications, equivalents, and / or alternatives to the embodiments of the present invention.

[0014] The various embodiments and terms used herein should not be understood to limit the technical features described herein to a specific embodiment, but should encompass various modifications, equivalents, or alternatives of the embodiment. In connection with the description of the drawings, similar reference numerals may be used for similar or related components. The singular form of a noun corresponding to an item can include one or more of the item, unless the relevant context clearly dictates otherwise. In this document, phrases such as "A or B," "at least one of A and B," "at least one of A or B," "A, B, or C," "at least one of A, B, and C," and "at least one of A, B, or C" each include any one of the items listed together in the phrase, or all possible combinations thereof. Terms such as "first," "second," "first," or "second" may be used merely to distinguish a component from other components and do not limit the component in other respects (e.g., importance or order). When a (e.g., first) component is referred to as "coupled" or "connected" to another (e.g., second) component, with or without the terms "functionally" or "communicatively," it means that the component can be coupled to the other component directly (e.g., by wire), wirelessly, or through a third component.

[0015] The term "module" as used in various embodiments herein may include a unit implemented in hardware, software, or firmware, and may be used interchangeably with terms such as logic, logic block, component, or circuit. A module may be an integrated component or the smallest unit or portion of such a component that performs one or more functions. For example, in one embodiment, a module may be implemented in the form of an application-specific integrated circuit (ASIC).

[0016] Various embodiments of this document may be embodied as software (e.g., a program) including one or more instructions stored in a machine-readable storage medium (e.g., internal memory or external memory). For example, the machine can retrieve and execute at least one instruction from the one or more stored instructions. This allows the machine to be operated to perform at least one function in accordance with the retrieved at least one instruction. The one or more instructions may include code generated by a compiler or code that can be executed by an interpreter. The machine-readable storage medium may be provided in the form of a non-transitory storage medium. Here, "non-transitory" simply means that the storage medium is a tangible device and does not contain a signal (e.g., electromagnetic wave), and this term does not distinguish between data being stored semi-permanently and data being temporarily stored in the storage medium.

[0017] According to one embodiment, methods according to various embodiments disclosed herein may be provided in a computer program product. The computer program product may be traded as a commodity between a seller and a buyer. The computer program product may be distributed in the form of a machine-readable storage medium (e.g., a compact disc read-only memory (CD-ROM)) or distributed online (e.g., downloaded or uploaded) via an application store or directly between two user devices. In the case of online distribution, at least a portion of the computer program product may be at least temporarily stored or temporarily generated in a machine-readable storage medium, such as the memory of a manufacturer's server, an application store server, or an intermediary server.

[0018] According to various embodiments, each of the above components (e.g., modules or programs) may include one or more entities, and some of the entities may be located separately in other components. According to various embodiments, one or more of the above components or operations may be omitted, or one or more other components or operations may be added. Generally or additionally, multiple components (e.g., modules or programs) may be integrated into a single component. In this case, the integrated component may perform one or more functions of each of the multiple components in a manner that is the same as or similar to that performed by that component of the multiple components before the integration. According to various embodiments, operations performed by a module, program, or other component may be performed sequentially, in parallel, repeatedly, or heuristically, or one or more of the operations may be performed in a different order, omitted, or one or more different operations may be added.

[0019] 1 and 2 are diagrams showing fuel cell systems according to various embodiments.

[0020] 1, the fuel cell system for a vehicle may include a first cooling line 110 through which a first coolant circulates via a fuel cell stack 10 of the vehicle, a second cooling line 120 through which a second coolant circulates via power electronic parts 200 of the vehicle, and a heat exchanger 300 for mutually exchanging heat between the first coolant and the second coolant. The first cooling line 110 and the second cooling line 120 may form a thermal management system (TMS) line through which the first coolant and the second coolant flow while exchanging heat. In this case, the first coolant or the second coolant may be used as a cooling medium or a heat medium in the TMS line.

[0021] The fuel cell system may also include a first connecting line 130 that forms a heating loop (heating circulation path) with the first cooling line 110, a second connecting line 150 that forms a cooling / heating loop with the first cooling line 110, and a third connecting line 140 that forms a cooling loop with the first cooling line 110 to cool the first coolant. For example, as shown in FIG. 2, the first coolant may be cooled or heated while circulating through the first connecting line 130, the second connecting line 150, or the third connecting line 140.

[0022] The first cooling line 110 may be configured to form a cooling loop that cools the first coolant or a heating loop that heats (increases the temperature) the first coolant depending on the state of the vehicle. For example, the first cooling line 110 may be configured to form a heating loop to ensure cold start capability when the vehicle is initially started, and to form a cooling loop to release heat generated from the fuel cell stack 10 to the outside while the vehicle is running. The fuel cell stack 10, the first valve 20, the first pump 30, the second valve 40, and the first radiator 60 may be arranged on the first cooling line 110 through which the first coolant circulates.

[0023] The fuel cell stack 10 (which may also be referred to as a "fuel cell") may be formed in a structure capable of producing electricity through an oxidation-reduction reaction between a fuel (e.g., hydrogen) and an oxidant (e.g., air). For example, the fuel cell stack 10 may include a membrane electrode assembly (MEA) having an electrolyte membrane through which hydrogen ions move and catalyst electrode layers attached to both sides of the membrane where an electrochemical reaction occurs, a gas diffusion layer (GDL) that uniformly distributes reactant gases and transfers generated electrical energy, a gasket and fastening mechanism for maintaining airtightness and an appropriate fastening pressure between the reactant gases and the first coolant, and a bipolar plate that transports the reactant gases and the first coolant.

[0024] 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 the flow paths of the separator plate. The hydrogen supplied to the anode is decomposed into protons and electrons by catalysts in the electrode layers formed on both sides of the electrolyte membrane. Only the protons are selectively transferred to the cathode through the electrolyte membrane, which is a cation exchange membrane, and the electrons are transferred to the cathode through the conductor gas diffusion layer and separator plate. At the cathode, the protons supplied through the electrolyte membrane and the electrons transferred through the separator plate come into contact with oxygen in the air supplied to the cathode by an air supply device, resulting in a reaction that produces water. The movement of the protons generates a flow of electrons through an external conductor, which can generate an electric current.

[0025] The first valve 20 can switch the flow path of the first coolant on the first cooling line 110 to the first connection line 130 in which the heater 50 is disposed or to the fuel cell stack 10. For example, the first valve 20 can be connected to one end of the first pump 30, one end of the first connection line 130, and one end of the fuel cell stack 10 on the first cooling line 110. The first valve 20 can include various valve means that can selectively switch the flow path of the first coolant. For example, the first valve 20 can be a three-way valve. In this case, the first valve 20 can include a first port 21 connected to the first cooling line 110 to allow the first coolant pumped by the first pump 30 to flow in, a second port 22 connected to the first cooling line 110 to allow the first coolant passing through the first valve 20 to flow into the fuel cell stack 10, and a third port 23 connected to one end of the first connection line 130. 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 switched to either the heater 50 or the fuel cell stack 10 of the first connecting line 130. That is, when the second port 22 is opened and the third port 23 is closed, the first coolant flows into the fuel cell stack 10, and conversely, when the third port 23 is opened and the second port 22 is closed, the first coolant can flow into the heater 50 via the first connecting line 130.

[0026] The first connection line 130 may form a heating loop (heating circulation path) with the first cooling line 110 to heat the first coolant. For example, the first coolant flowing along the first connection line 130 may be heated while passing through a heater 50 installed in the first connection line 130. One end of the first connection line 130 may be connected to the first cooling line 110 at a first point located between an outlet of the first pump 30 and the fuel cell stack 10, and the other end of the first connection line 130 may be connected to the first cooling line 110 at a second point located between an inlet of the first pump 30 and the fuel cell stack 10. Here, the inlet of the first pump 30 may be defined as an inlet through which the first coolant flows into the first pump 30. The outlet of the first pump 30 may be defined as an outlet through which the first coolant passing through the first pump 30 is discharged. In addition, the section between the outlet of the first pump 30 and the fuel cell stack 10 may be defined as a section through which the first coolant discharged from the first pump 30 flows to a first coolant inlet (not shown) of the fuel cell stack 10. In addition, the section between the inlet of the first pump 30 and the fuel cell stack 10 may be defined as a section through which the first coolant discharged from a coolant outlet (not shown) of the fuel cell stack 10 flows to the inlet of the first pump 30.

[0027] The first pump 30 may be configured to forcibly flow the first cooling water. The first pump 30 may include various means capable of pumping the first cooling water, and the type and number of the first pumps 30 are not limited herein.

[0028] The second valve 40 can switch the flow path of the first coolant on the first cooling line 110 to either the first radiator 60 or the fuel cell stack 10. For example, the second valve 40 can be provided on the first cooling line 110 to be located between the first pump 30 and the first radiator 60, and can be connected to one end of the third connection line 140 and one end of the second connection line 150. The second valve 40 can include various valve means that can selectively switch the flow path of the first coolant to either the first radiator 60 or the fuel cell stack 10. For example, the second valve 40 can be a four-way valve. In this case, the second valve 40 may include 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 coolant passing through the first radiator 60 flows in, a third port 43 connected to one end of the second connection line 150, and a fourth port 44 connected to the first cooling line 110 so that the first coolant flows into the first pump 30. 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 may be switched between the first radiator 60 and 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 60. 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 60.

[0029] The second connection line 150 may form a heating / cooling loop with the first cooling line 110 to heat / cool the air conditioning unit (HAVC unit) 90. As an example, the second connection line 150 may form a loop to heat a heater (not shown) for the air conditioning unit 90. One end of the second connection line 150 may be connected to the first cooling line 110 between a first point (a point where one end of the first connection line 130 is connected to the first cooling line 110) and an inlet of the fuel cell stack 10, and a portion of the first coolant may circulate through the second connection line 150. The other end of the second connection line 150 may be connected to the first cooling line 110 between the first pump 30 and a second point (a point where the other end of the first connection line 130 is connected to the first cooling line 110).

[0030] The second connecting line 150 may be provided with an ion filter 95 that filters ions in the first coolant that has passed through the air conditioning unit 90. If the electrical conductivity of the first coolant increases due to corrosion or exudation in the system, electricity may flow through the first coolant, causing a short circuit in the fuel cell stack 10 or current to flow toward the first coolant. Therefore, the first coolant must maintain low electrical conductivity. The ion filter 95 may be configured to remove ions contained in the first coolant to maintain the electrical conductivity of the first coolant below a predetermined level. During a cold start in which the supply of first coolant to the fuel cell stack 10 is cut off (the second port 22 of the first valve 20 is cut off), the first coolant circulates through the heater 50 of the first connecting line 130 (heating loop) and also circulates along the second connecting line 150. This allows filtering (removal of ions contained in the first coolant) by the ion filter 95 provided in the second connecting line 150, even during a cold start. Therefore, immediately after a cold start, the electrical conductivity of the first coolant flowing into the fuel cell stack 10 can be maintained at a predetermined level or less.

[0031] The third connecting line 140 may form a cooling loop with the first cooling line 110 to cool the first coolant. For example, one end of the third connecting line 140 may be connected to the first cooling line 110 between the first pump 30 and the first radiator 60, and the other end of the third connecting 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 60.

[0032] The first radiator 60 may be configured to cool the first coolant. The first radiator 60 may be formed in various structures capable of cooling the first coolant, and the present invention is not limited or restricted by the type and structure of the first radiator 60. The first radiator 60 may be connected to a first reservoir 62 in which the first coolant is stored.

[0033] 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 20), 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. The fuel cell system may control the inflow flow rate of the first coolant flowing into the fuel cell stack 10 based on the temperatures measured by the first temperature sensor 112, the second temperature sensor 114, and the third temperature sensor 116. For example, if the measured temperature of the first coolant circulating along the first cooling line 110 is lower than a preset target temperature, the inflow flow rate of the first coolant may be controlled to be lower than a preset set flow rate. In this way, when the measured temperature of the first coolant is low, the inflow flow rate of the first coolant flowing into the fuel cell stack 10 can be controlled to be low, thereby achieving the advantageous effect of minimizing thermal shock and performance degradation caused by the difference between the temperature of the first coolant stagnating inside the fuel cell stack 10 and the temperature of the first coolant flowing into the fuel cell stack 10.

[0034] The second cooling line 120 is configured to pass through the vehicle's power electronic parts 200, and the second cooling water can circulate along the second cooling line 120. Here, the vehicle's power electronic parts 200 can be understood as parts that use the vehicle's power source as an energy source, and the present invention is not limited or restricted by the type and number of the vehicle's power electronic parts 200. As an example, the electrical component 200 may include at least one of a second pump 205 for pumping a second coolant, a bi-directional high voltage DC-DC converter (BHDC) 210 provided between the fuel cell stack 10 and the vehicle's high voltage battery (not shown), a blower pump control unit (BPCU) 220 for controlling a blower (not shown) for supplying outside air for driving the fuel cell stack 10, a low-voltage DC-DC converter (LDC) 230 for converting high DC voltage supplied from the high voltage battery into low DC voltage, an air compressor (ACP) 240 for compressing air supplied to the fuel cell stack 10, and an air cooler 250.

[0035] A second pump (not shown) for forcibly flowing the second cooling water may be disposed on the second cooling line 120. The second pump may include a pumping means capable of pumping the second cooling water, and the type and characteristics of the second pump are not limited or restricted.

[0036] A second radiator 70 for cooling the second coolant may be disposed on the second cooling line 120. The second radiator 70 may be formed in various structures capable of cooling the second coolant, and the type and structure of the second radiator 70 are not limited or restricted. The second radiator 70 may be connected to a second reservoir 72 in which the second coolant is stored.

[0037] In an embodiment, the first radiator 60 and the second radiator 70 may be configured to be cooled simultaneously by a single cooling fan 80. As an example, the first radiator 60 and the second radiator 70 may be arranged in parallel, and the cooling fan 80 may be configured to blow outside air to the first radiator 60 and the second radiator 70. By simultaneously cooling the first radiator 60 and the second radiator 70 by a single cooling fan 80, the structure of the fuel cell system may be simplified, design freedom and space utilization may be improved, and power consumption for cooling the first radiator 60 and the second radiator 70 may be minimized.

[0038] The heat exchanger 300 may be configured to mutually exchange heat between the first coolant and the second coolant. Because the temperature of the second coolant that cools the electrical components is relatively lower than the temperature of the first coolant that cools the fuel cell stack 10, the fuel cell system can mutually exchange heat between the first coolant and the second coolant, thereby lowering the temperature of the first coolant without increasing the capacity of the first radiator 60 and the cooling fan 80. This improves the cooling efficiency of the fuel cell stack 10 and provides advantageous effects of improving safety and reliability. In addition, the fuel cell system can lower the temperature of the first coolant when a vehicle (e.g., construction machinery) is stopped and cannot use wind while traveling, thereby ensuring high-power operation of the fuel cell stack 10 and providing advantageous effects of improving safety and durability.

[0039] In this embodiment, the heat exchanger 300 is connected to the first cooling line 110 between the outlet of the first radiator 60 and the fuel cell stack 10, and the second cooling line 120 may connect the outlet of the second radiator 70 to electrical components via the heat exchanger 300. For example, the first coolant may flow along the heat exchanger 300 connected to the first cooling line 110, and the second cooling line 120 may pass through the heat exchanger 300 so as to be exposed to the first coolant (e.g., the first coolant flows along the periphery of the second cooling line 120). In this manner, the temperature of the first coolant flowing into the fuel cell stack 10 may be lowered by mutual heat exchange between the first coolant and the second coolant. The first temperature of the first coolant passing through the first radiator 60 may be higher than the second temperature of the second coolant passing through the second radiator 70, and the third temperature of the first coolant passing through the heat exchanger 300 may be lower than the first temperature. As an example, the first temperature of the first cooling water may be approximately 10°C higher than the second temperature of the second cooling water, and the third temperature of the first cooling water that has passed through the heat exchanger 300 (exchanged heat with the second cooling water) may be 1°C lower than the first temperature.

[0040] When a vehicle equipped with a fuel cell system is moving, the first coolant flowing into the fuel cell stack 10 can be cooled not only by the cooling fan 80 but also by wind generated by the vehicle's speed. When the vehicle is stopped, no wind is generated by the vehicle's speed, so the first coolant can be cooled by the cooling fan 80. However, in vehicles that perform tasks such as leveling or loading even when stopped, such as construction machinery, the amount of cooling provided by the cooling fan 80 may be insufficient. The fuel cell system according to the embodiment determines the rotation speed of the cooling fan 80 taking into account the output value of the fuel cell stack 10, thereby efficiently cooling the fuel cell stack 10 even when there is no wind. Furthermore, the fuel cell system according to the embodiment can more precisely adjust the amount of cooling by correcting the rotation speed of the cooling fan 80 according to the temperature of the coolant, even in low-output sections of the fuel cell stack 10.

[0041] 3 and 4 are diagrams showing other examples of fuel cell systems according to various embodiments.

[0042] 1 and 2 is disposed separately from the first radiator 60, but in the embodiment of FIG. 3, the heat exchanger 300' may be directly connected to the first radiator 60. The heat exchanger 300' may be formed in various structures that can be connected to the first radiator 60, and the structure and connection structure of the heat exchanger 300' are not limited or restricted. For example, the heat exchanger 300' may be connected to a specified position (upper left end) of the first radiator 60, but the specified position of the first radiator 60 to which the heat exchanger 300' is connected may be changed.

[0043] 4, a first cooling fan 80 for cooling the first radiator 60 and a second cooling fan 100 for cooling the second radiator 70 may be separately arranged. In this case, the fuel cell system may eliminate parameters related to the thermal load of the electrical components 200 when controlling the rotation speed of the first cooling fan 80.

[0044] 5 is a block diagram of a fuel cell system for controlling a cooling fan according to various embodiments. Referring to FIG. 5, the fuel cell system may include a sensor unit 510, a cooling fan control unit 520, and a cooling fan 530.

[0045] The cooling fan 530 may be configured to cool the first coolant passing through the fuel cell stack 10. The cooling fan 530 may correspond to, for example, the cooling fan 80 of FIG.

[0046] The sensor unit 510 may include at least one sensor 512, 514 capable of measuring temperature. For example, the outside air temperature sensor 512 may measure the outside air temperature of the fuel cell system (or vehicle). The outside air temperature sensor 512 may be disposed on the entire surface of the first radiator 60 or the second radiator 70. The coolant temperature sensor 514 may measure the temperature of the coolant at a point corresponding to the inlet of the fuel cell stack 10 (e.g., a position corresponding to the first temperature sensor 112 in FIG. 1). According to an embodiment, the outside air temperature sensor 512 and the coolant temperature sensor 514 may be embodied in a single integrated module or in separate configurations.

[0047] The cooling fan control unit 520 may be a hardware or software module for controlling the cooling fan 530 in the fuel cell system. The cooling fan control unit 520 is electrically connected to the sensor unit 510 and the cooling fan 530, and may perform the overall operation of the fuel cell system, such as controlling the rotation speed of the cooling fan 530. For example, the cooling fan control unit 520 may determine the rotation speed of the cooling fan 530 in consideration of the outside air temperature measured by the sensor unit 510 and the output value of the fuel cell stack 10. The output value of the fuel cell stack 10 (or the output value of the fuel cell) may be determined by a control device (e.g., a fuel-cell control unit (FCU)) of the fuel cell stack 10. The cooling fan control unit 520 may correct the determined rotation speed of the cooling fan 530 based on the temperature of the coolant at the inlet of the fuel cell stack 10 measured by the sensor unit 510. Specifically, the cooling fan control unit 520 corrects the rotation speed of the cooling fan 530 in the low output section where the output value of the fuel cell is below a critical value, thereby ensuring cooling performance in a situation where a thermal load may occur in the fuel cell stack 10 or the electrical components 200 while the vehicle is stopped.

[0048] 6 is a flowchart illustrating an operation for controlling a cooling fan according to various embodiments. The operations illustrated in the flowcharts of FIGS. 6 to 8 may be implemented by the fuel cell system or by a component (e.g., cooling fan control unit 520) included in the fuel cell system.

[0049] 6, in operation 610, the fuel cell system can measure the outside air temperature and the coolant temperature at the fuel cell inlet via the sensor unit 510. The fuel cell system can measure the outside air temperature and the coolant temperature at a specified interval or whenever a specified event occurs (e.g., when the vehicle is started, driven, stopped, or operated).

[0050] In operation 620, the fuel cell system can determine the rotation speed of the cooling fan 530 by the cooling fan control unit 520. The cooling fan control unit 520 can determine the rotation speed of the cooling fan 530 based on the outside air temperature and the output value of the fuel cell (or fuel cell stack 10).

[0051] In operation 630, the fuel cell system can correct the rotation speed of the cooling fan 530 by the cooling fan control unit 520. The cooling fan control unit 520 can correct the rotation speed of the cooling fan 530 based on the temperature of the cooling water at the inlet of the fuel cell.

[0052] 7 is a flowchart of an operation for determining the rotation speed of a cooling fan according to various embodiments. For example, the operation of FIG. 7 may be expressed as an example of operation 620 of FIG.

[0053] 7, the fuel cell system can calculate the amount of heat generated by the fuel cell based on the output value of the fuel cell in operation 710. Since the amount of heat generated corresponds to the internal loss of the fuel cell, the cooling fan control unit 520 can calculate the amount of heat generated by the difference between the output value / output efficiency and the output value.

[0054] In operation 720, the fuel cell system can calculate the temperature of the coolant at the outlet of the fuel cell based on the heat generation amount of the fuel cell and the temperature of the coolant at the inlet of the fuel cell. In this case, the cooling fan control unit 520 can calculate the temperature of the coolant at the outlet of the fuel cell by substituting a target coolant temperature at the inlet of the fuel cell required to maintain an appropriate temperature of the fuel cell, without using the temperature of the coolant at the inlet of the fuel cell measured by the sensor unit 510. The temperature of the coolant at the outlet of the fuel cell can correspond to the temperature of the coolant at the inlet of a radiator (e.g., first radiator 60 in FIG. 1). According to an embodiment, the cooling fan control unit 520 can further calculate the temperature of the coolant at the outlet of the fuel cell based on the rotation speed of a pump (e.g., first pump 30 in FIG. 1) that pumps the coolant.

[0055] In operation 730, the fuel cell system can calculate the airflow or speed of the cooling fan 530 for a target coolant temperature at the inlet of the fuel cell based on the coolant temperature at the outlet of the fuel cell and the ambient temperature.

[0056] In operation 740, the fuel cell system may determine the rotation speed of the cooling fan 530 based on the calculated air volume or wind speed. According to an embodiment, the cooling fan control unit 520 may store table information (e.g., a look-up table) indicating the relationship between the outside air temperature, the output value of the fuel cell, and the rotation speed of the cooling fan 530 as a database. For example, the table information may be expressed in the form of Table 1 below.

[0057] [Table 1]

[0058] In [Table 1], the output values of the fuel cell can have the relationship of 0 < A < B < C < D < E. Also, as the output value of the fuel cell or the outside air temperature increases, the rotation speed of the cooling fan 530 increases, but it is not necessarily in a directly proportional relationship. Since the performance of the cooling fan 530 is finite, the cooling fan control unit 520 can set the rotation speed of the cooling fan 530 above a predetermined level as the maximum rotation speed. For example, W 40E , W 50D , and W 50E can all be the same as the maximum rotation speed. Conversely, when the cooling fan 530 rotates below a predetermined level, since it has no effect on the cooling performance, the cooling fan control unit 520 can set the rotation speed of the cooling fan 530 below the predetermined level as the minimum rotation speed.

[0059] Since the values indicating the outside air temperature, the output value of the fuel cell, and the rotation speed of the cooling fan 530 are discrete, the intermediate values of the values represented in the table information can be processed by interpolation. For example, when the outside air temperature is 0 degrees and the output value of the fuel cell is between A and B, the cooling fan control unit 520 can set the rotation speed of the cooling fan 530 as W 0A . When the output value of the fuel cell is smaller than A, such as when the vehicle (e.g., construction machinery) stops, the cooling fan control unit 520 can set the rotation speed of the cooling fan 530 to 0. In this case, the cooling performance can be significantly reduced due to the increase or decrease of the heat load of the electrical components 200 or the ventilation resistance on the air movement path. The fuel cell system according to the embodiment can correct the rotation speed determined based on the temperature of the cooling water at the inlet of the fuel cell in order to ensure the cooling performance.

[0060] FIG. 8 is a flowchart of an operation for correcting the rotation speed of the cooling fan according to various embodiments.

[0061] 8, in operation 810, the fuel cell system may determine whether the output value of the fuel cell is in a low power range via the cooling fan control unit 520. The low power range may indicate, for example, when the output value of the fuel cell is less than a specified critical value (e.g., “A” in Table 1) or when the determined rotation speed of the cooling fan 530 is 0. If the output value of the fuel cell is not in the low power range, the fuel cell system may repeat operation 810.

[0062] If the output value of the fuel cell is in the low output section, in operation 820, the fuel cell system may check via the cooling fan control unit 520 whether the temperature of the cooling water at the inlet of the fuel cell is above a critical value.

[0063] If the temperature of the cooling water at the inlet of the fuel cell is equal to or higher than the critical value, the fuel cell system may correct the rotation speed of the cooling fan 530 via the cooling fan control unit 520 in operation 830. In this case, the cooling fan control unit 520 may set the rotation speed of the cooling fan 530, which was set to 0, as the minimum rotation speed, thereby ensuring cooling performance and reducing unnecessary power consumption.

[0064] If the temperature of the cooling water at the inlet of the fuel cell is below a critical value, the fuel cell system can control the cooling fan 530 to be turned off via the cooling fan control unit 520 . [Explanation of symbols]

[0065] 10 fuel cell stack, 20 first valve, 21 first port, 22 second port, 23 third port, 30 first pump, 40 second valve, 41 first port, 42 second port, 44 third port, 50 heater, 60 first radiator, 62 first reservoir, 70 second radiator, 72 second reservoir, 80 cooling fan (first cooling fan), 90 air conditioning unit, 95 ion filter, 100 second cooling fan, 110 first cooling line, 112 first temperature sensor, 114 second temperature sensor, 116 third temperature sensor, 120 second cooling line, 130 first connecting line, 140 third connecting line, 150 second connecting line, 200 electrical components, 205 second pump, 210 BHDC, 220 BPCU, 230 LDC, 240 air compressor, 250 Air cooler, 300 heat exchanger, 510 sensor unit, 512 outside air temperature sensor, 514 coolant temperature sensor, 520 cooling fan control unit, 530 cooling fan.

Claims

1. 1. A fuel cell system, comprising: a sensor unit configured to measure the temperature of the cooling water at the inlet of the fuel cell and the ambient temperature; a cooling fan that cools the cooling water; a cooling fan control unit connected to the sensor unit and the cooling fan; The cooling fan control unit determining a rotation speed of the cooling fan based on the outside air temperature and the output value of the fuel cell; correcting the rotation speed of the cooling fan based on the temperature of the cooling water at the inlet of the fuel cell; calculating a heat generation amount of the fuel cell based on the output value of the fuel cell; calculating a temperature of the cooling water at an outlet of the fuel cell based on the heat generation amount of the fuel cell and the temperature of the cooling water at an inlet of the fuel cell; calculating an air volume or air speed for a target cooling water temperature at an inlet of the fuel cell based on the cooling water temperature at an outlet of the fuel cell and the outside air temperature; The fuel cell system is configured to determine the rotation speed of the cooling fan based on the air volume or air speed.

2. The sensor unit a coolant temperature sensor configured to measure the temperature of the coolant at the inlet of the fuel cell; 2. The fuel cell system of claim 1, further comprising an outside air temperature sensor configured to measure said outside air temperature.

3. The cooling fan control unit confirming that the output value of the fuel cell is in a low output section; If the output value of the fuel cell is in the low output section, it is determined whether the temperature of the cooling water at the inlet of the fuel cell is equal to or higher than a first critical value; correcting the rotation speed of the cooling fan when the temperature of the cooling water at the inlet of the fuel cell is equal to or higher than the first critical value; 2. The fuel cell system according to claim 1, wherein the cooling fan is controlled to be turned off when the temperature of the cooling water at the inlet of the fuel cell is lower than the first critical value.

4. The cooling fan control unit 4. The fuel cell system of claim 3, wherein the output value of the fuel cell is determined to be in the low output section when the output value of the fuel cell is less than a second critical value or the determined cooling fan rotation speed is 0.

5. The cooling fan control unit 5. The fuel cell system according to claim 4, wherein the rotational speed of the cooling fan is corrected from 0 to a minimum rotational speed when the temperature of the cooling water at the inlet of the fuel cell is equal to or higher than the first critical value.

6. a first cooling line through which first cooling water circulates via the fuel cell; a first radiator disposed on the first cooling line and configured to cool the first cooling water; a second cooling line through which second cooling water circulates via the electrical components; a second radiator disposed on the second cooling line and configured to cool the second cooling water; 2. The fuel cell system according to claim 1, wherein the cooling fan is configured to cool the first radiator and the second radiator simultaneously.

7. a first cooling line through which first cooling water circulates via the fuel cell; a first radiator disposed on the first cooling line and configured to cool the first cooling water; a second cooling line through which second cooling water circulates via the electrical components; a second radiator disposed on the second cooling line and configured to cool the second cooling water; 2. The fuel cell system according to claim 1, wherein the cooling fan is configured to cool the first radiator.

8. 1. A method of operating a fuel cell system, comprising: measuring the temperature of the cooling water at the inlet of the fuel cell; The operation of measuring the outside temperature, determining the rotation speed of a cooling fan for cooling the coolant based on the outside air temperature and the output value of the fuel cell; and correcting the rotation speed of the cooling fan based on the temperature of the cooling water at the inlet of the fuel cell, The operation of determining the rotation speed of the cooling fan includes: calculating a heat generation amount of the fuel cell based on an output value of the fuel cell; an operation of calculating the temperature of the cooling water at the outlet of the fuel cell based on the heat generation amount of the fuel cell and the temperature of the cooling water at the inlet of the fuel cell; calculating an air volume or air speed for a target cooling water temperature at the inlet of the fuel cell based on the cooling water temperature at the outlet of the fuel cell and the outside air temperature; and determining a rotation speed of the cooling fan based on the air volume or air speed.

9. an operation of confirming that the output value of the fuel cell is in a low output section; determining whether the temperature of the cooling water at the inlet of the fuel cell is equal to or greater than a first critical value; 9. The method of claim 8, further comprising: correcting the rotation speed of the cooling fan from 0 to a minimum rotation speed when the temperature of the cooling water at the inlet of the fuel cell is equal to or greater than the first critical value; or controlling the cooling fan to be off when the temperature of the cooling water at the inlet of the fuel cell is less than the first critical value.

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