Temperature control device for fuel cell system and method for operating fuel cell system

Abstract

The present application relates to a temperature control device for a fuel cell system and a method for operating the fuel cell system. A fuel cell system includes: a fuel cell stack; a first cooling line configured to circulate a first coolant through the fuel cell stack; a first radiator arranged on the first cooling line; a valve configured to switch a flow path of the first coolant to the fuel cell stack or the first radiator; and a controller connected to the valve and configured to: set a target temperature at an inlet of the fuel cell stack and a correction coefficient for controlling an opening of the valve; measure a first coolant temperature at an outlet of the fuel cell stack and a second coolant temperature at an outlet of the first radiator; calculate an opening of the valve based on the first coolant temperature, the second coolant temperature, the target temperature, and the correction coefficient; and, in response to the opening being within a first range, correct the correction coefficient based on a comparison of a third coolant temperature at the inlet of the fuel cell stack with the target temperature.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority from Korean Patent Application No. 10-2021-0065745 filed on May 21, 2021, in the Korean Intellectual Property Office, the entire contents of which are incorporated herein by reference for all purposes. Technical Field

[0003] The present disclosure relates to techniques for controlling the temperature of a coolant in a fuel cell system. Background Art

[0004] A fuel cell system can generate electrical energy by using a fuel cell stack. For example, when hydrogen is used as fuel for a fuel cell stack, it may be a measure to solve global environmental problems, so research and development of fuel cell systems are continuously underway. A fuel cell system may include: 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 in the air (as an oxidant required for the electrochemical reaction) to the fuel cell stack; and a thermal management system (TMS) that removes the reaction heat of the fuel cell stack to the outside, controls the operating temperature of the fuel cell stack, and performs water management functions.

[0005] The thermal management system is a cooling device that circulates an antifreeze liquid used as a coolant in the fuel cell stack and maintains the fuel cell stack at an appropriate temperature (e.g., 60-70°C), and may include a TMS line in which the coolant circulates, a reservoir for storing the coolant, a pump for circulating the coolant, an ion filter for removing ions included in the coolant, and a radiator for discharging heat of the coolant to the outside. In addition, the thermal management system may include a heater for heating the coolant and an air conditioning unit (e.g., a heater for heating) that cools and heats the interior of a device (e.g., a vehicle) including the fuel cell system by using the coolant. The thermal management system can maintain the appropriate temperature of the power electronic components of the vehicle as well as the fuel cell stack. Summary of the Invention

[0006] This summary is provided to introduce some concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed claims, nor is it intended to be used as an aid in determining the scope of the claimed claims.

[0007] In one general aspect, a temperature control device for a fuel cell system is provided, comprising: a fuel cell stack; a first cooling line configured to circulate a first coolant through the fuel cell stack; a first radiator arranged on the first cooling line and configured to cool the first coolant; a valve configured to switch a flow path of the first coolant to the fuel cell stack or the first radiator; and a controller connected to the valve, the controller being configured to: set a target temperature at the inlet of the fuel cell stack and a correction coefficient for controlling an opening of the valve; measure a first coolant temperature at the outlet of the fuel cell stack and a second coolant temperature at the outlet of the first radiator; calculate an opening of the valve based on the first coolant temperature, the second coolant temperature, the target temperature and the correction coefficient; and in response to the opening being within a first range, correct the correction coefficient based on a comparison of a third coolant temperature at the inlet of the fuel cell stack with the target temperature.

[0008] The controller can be configured to: set the correction coefficient to a previous value in response to the difference between the third coolant temperature and the target temperature being within the second range; reduce the correction coefficient in response to the difference between the third coolant temperature and the target temperature deviating from the second range and the target temperature being higher than the third coolant temperature; and increase the correction coefficient in response to the difference between the third coolant temperature and the target temperature deviating from the second range and the target temperature being lower than the third coolant temperature.

[0009] The apparatus may include a first temperature sensor disposed at an inlet of the fuel cell stack, a second temperature sensor disposed at an outlet of the fuel cell stack, and a third temperature sensor disposed at an outlet of the first radiator.

[0010] The device may include a cooling fan arranged on the first cooling line and configured to blow external air to the first radiator; and a pump arranged on the first cooling line and configured to pump the first coolant, wherein the controller is configured to control the RPM of at least one of the cooling fan and the pump in response to the opening degree deviating from the first range.

[0011] The controller can be configured to control the RPM of the cooling fan and the RPM of the pump so that by decreasing the RPM of the cooling fan and increasing the RPM of the pump, as the third coolant temperature reaches the target temperature, the total power consumption becomes minimum, wherein the total power consumption is the sum of the power consumption corresponding to the RPM of the cooling fan and the power consumption corresponding to the RPM of the pump.

[0012] The controller may include: a valve controller configured to control an opening degree of the valve; a cooling fan controller configured to control an RPM of the cooling fan; and a pump controller configured to control an RPM of the pump.

[0013] Valve controllers, cooling fan controllers and pump controllers can be integrated in one module.

[0014] The apparatus may include: a second cooling line configured to circulate a second coolant through the electrical component; a second radiator disposed on the second cooling line and configured to cool the second coolant; a heat exchanger configured to exchange heat between the first coolant and the second coolant; and a cooling fan configured to cool any one or any combination of the first radiator and the second radiator.

[0015] In another general aspect, a processor-implemented method for operating a fuel cell system including a fuel cell stack is provided, the method comprising: setting a target temperature at an inlet of the fuel cell stack and a correction coefficient for controlling an opening of a valve; measuring a first coolant temperature at an outlet of the fuel cell stack and a second coolant temperature at an outlet of a first radiator; calculating an opening of the valve based on the first coolant temperature, the second coolant temperature, the target temperature, and the correction coefficient; and correcting the correction coefficient based on a comparison of a third coolant temperature at the inlet of the fuel cell stack with the target temperature in response to the opening being within a first range.

[0016] Correction of the correction coefficient includes: in response to the difference between the third coolant temperature and the target temperature being within the second range, setting the correction coefficient to a previous value; in response to the difference between the third coolant temperature and the target temperature deviating from the second range and the target temperature being higher than the third coolant temperature, reducing the correction coefficient; and in response to the difference between the third coolant temperature and the target temperature deviating from the second range and the target temperature being lower than the third coolant temperature, increasing the correction coefficient.

[0017] The method may include controlling the RPM of any one or any combination of the cooling fan and the pump in response to the opening degree deviating from the first range.

[0018] The control of the RPM may include controlling the RPM of the cooling fan and the RPM of the pump so that by decreasing the RPM of the cooling fan and increasing the RPM of the pump, as the third coolant temperature reaches the target temperature, the total power consumption becomes minimum, wherein the total power consumption is the sum of the power consumption corresponding to the RPM of the cooling fan and the power consumption corresponding to the RPM of the pump.

[0019] Other features and aspects will be apparent from the following detailed description, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description in conjunction with the accompanying drawings:

[0021] Figure 1 shows a fuel cell system according to various embodiments;

[0022] Figure 2 shows a fuel cell system according to various embodiments;

[0023] Figure 3 A block diagram of a fuel cell system according to various embodiments is shown, wherein a first coolant flows;

[0024] Figures 4A to 4C shows the flow of coolant according to the opening degree of the valve according to various embodiments;

[0025] Figure 5 A block diagram of a fuel cell system according to various embodiments is shown.

[0026] Figure 6 A flow chart illustrating operations for controlling the opening degree of a valve and a correction factor according to various embodiments is shown.

[0027] Figure 7 A flowchart illustrating detailed operations for controlling the opening degree of a valve and a correction coefficient according to various embodiments is shown.

[0028] With regard to the description of the drawings, the same or similar components may be marked with the same or similar reference numerals. DETAILED DESCRIPTION

[0029] Hereinafter, various embodiments of the present disclosure will be described with reference to the accompanying drawings. Therefore, those skilled in the art will recognize that various modifications, equivalents and / or substitutions may be made to the various embodiments described herein without departing from the scope and spirit of the present disclosure.

[0030] The various embodiments of the present disclosure and the terms used herein do not limit the technical features described in the present disclosure to specific embodiments, and should be interpreted as including various modifications, equivalents or replacements of the embodiments. With regard to the description of the accompanying drawings, similar parts can be represented by similar figure numerals. It should be understood that the singular form of the noun corresponding to the project can include one or more things, unless the relevant context clearly indicates otherwise. As used herein, each of the 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" can include all possible combinations of the items listed together in the corresponding phrases. As used herein, terms such as "first (1st)" and "second (2nd)" or "first (first)" and "second (second)" can be used to simply distinguish corresponding parts from another part, and do not limit parts in other aspects (for example, importance or order). It should be understood that if an element (e.g., a first element) is referred to as being "coupled thereto" or "connected thereto" regardless of whether the term "operatively" or "communicatively" is used, this means that the element can be coupled to another element directly (e.g., by wire), wirelessly, or via a third element.

[0031] The term "module" used in various embodiments of the present disclosure may include units 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 part that performs one or more functions. For example, according to one embodiment, the module may be implemented in the form of an application-specific integrated circuit (ASIC).

[0032] Various embodiments of the present disclosure may be implemented by software (e.g., a program) that includes one or more instructions stored in a storage medium (e.g., an internal memory or an external memory) that can be read by a machine. For example, a device may call at least one instruction of the one or more instructions stored in the storage medium and may execute the instruction. This allows at least one function to be performed according to at least one of the called instructions. The one or more instructions may include code produced by a compiler or code executable by an interpreter. The storage medium that can be read by the device may be provided in the form of a non-transitory storage medium. Here, "non-transitory storage medium" means that the storage medium is a tangible device and does not include a signal (e.g., an electromagnetic wave), and with respect to this term, no distinction is made between the case where data is semi-permanently stored in the storage medium and the case where data is temporarily stored in the storage medium.

[0033] According to an embodiment, the method according to various embodiments of the present disclosure may be provided as included in a computer program product. The computer program product may be traded between a seller and a buyer. The computer program product may be distributed in the form of a storage medium that can be read by a device (e.g., a compact disc read-only memory (CD-ROM)), or may be stored by an application or distributed between two user devices directly or online (e.g., downloaded or uploaded). In online distribution, at least a portion of the computer program product may be at least temporarily stored in a storage medium, such as a memory of a manufacturer's server, an application store's server, or a relay server, which may be read by a device or temporarily generated.

[0034] According to various embodiments, the element (for example, module or program) of above-mentioned element can include one or more entities, and some of multiple entities can be arranged to be separated from other elements.According to various embodiments, in above-mentioned element, one or more elements or operations can be omitted, or one or more other elements or operations can be added.Alternatively or additionally, multiple elements (for example, module or program) can be integrated into one element.In this case, integrated element can perform one or more functions in multiple elements in a manner identical or similar to the function performed by the corresponding element in multiple elements before integration.According to various embodiments, the operation performed by module, program or other elements can be performed sequentially, in parallel, repeatedly or heuristically, and one or more operations can be performed or omitted in another order, or one or more other operations can be added.

[0035] Figure 1 and Figure 2 A fuel cell system according to various embodiments is shown.

[0036] Reference Figure 1 , a fuel cell system for a vehicle may include a first cooling line 110 in which a first coolant circulates through the fuel cell stack 10 of the vehicle; and a second cooling line 120 in which a second coolant circulates through the power electronic components 200 of the vehicle. In this embodiment, the fuel cell system may further include a heat exchanger 300 that exchanges heat between the first coolant and the second coolant, but the heat exchanger 300 may be omitted.

[0037] The fuel cell system may include a first connecting line 130, a second connecting line 150, and a third connecting line 140 to form a heating circuit (heating circulation path) with the first cooling line 110 or a cooling circuit with the first cooling line 110. The first coolant can be cooled or heated while circulating in the first connecting line 130, the second connecting line 150, or the third connecting line 140. As an example, the first cooling line 110 can form a heating circuit with the first connecting line 130 and the third connecting line 140 to ensure cold start capability under the initial startup conditions of the vehicle, and can also form a cooling circuit in which the first coolant passes through the first radiator 60, thereby dissipating heat generated by the fuel cell stack 10 while the vehicle is running. In another embodiment, when the temperature of the outside air reaches a certain temperature, the first cooling line 110 does not form a heating circuit, and the fuel cell system can ensure startup capability using the heat of the fuel cell stack 10. The fuel cell stack 10, the first valve 20, the first pump 30, the second valve 40, and the first radiator 60 can be arranged on the first cooling line 110, in which the first coolant circulates.

[0038] The fuel cell stack 10 (or may be referred to as a "fuel cell") may have a structure in which electricity can be generated through an oxidation / reduction reaction of a fuel (e.g., hydrogen) and an oxidant (e.g., air). As an example, the fuel cell stack 10 may include a membrane electrode assembly (MEA) in which a catalyst electrode layer for an electrochemical reaction is attached to opposite sides of an electrolyte membrane through which hydrogen ions travel; a gas diffusion layer (GDL) that uniformly distributes the reactant gas and transmits the generated electrical energy; a gasket and coupling mechanism for maintaining sealing and appropriate coupling pressure of the reactant gas and the first coolant; and a bipolar plate that allows the reactant gas and the first coolant to flow.

[0039] 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, and hydrogen can be supplied to the anode and air can be supplied to the cathode. The hydrogen supplied to the anode is decomposed into protons and electrons by the catalyst of the electrode layer provided on the opposite side of the electrolyte membrane, wherein only hydrogen ions can be transferred to the cathode after selectively passing through the electrolyte membrane as a cation exchange membrane, and electrons can be transferred to the cathode through the gas diffusion layer and the bipolar plate as a conductor. In the cathode, the hydrogen ions supplied through the electrolyte membrane and the electrons transported through the bipolar plate can meet the oxygen in the air supplied to the cathode by the air supply device, and a reaction to generate water occurs. Then, due to the flow of hydrogen ions, electrons can flow through the external wire, and due to the flow of electrons, an electric current can be generated.

[0040] The first valve 20 can switch the flow path of the first coolant to the first connecting line 130, where the heater 50 is located, or to the fuel cell stack 10 on the first cooling line 110. For example, the first valve 20 can be connected to one end of the first pump 30, one end of the first connecting 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 devices that can selectively switch the flow path of the first coolant. As an 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, allowing the first coolant pumped by the first pump 30 to be introduced therein; a second port 22 connected to the first cooling line 110, allowing the first coolant passing through the first valve 20 to be introduced into the fuel cell stack 10; and a third port 23 connected to one end of the first connecting line 130. As the second port 22 and the third port 23 of the first valve 20 are opened and closed, the flow path of the first coolant can be switched to the heater 50 on the first connecting line 130 or the fuel cell stack 10. That is, when the second port 22 is open and the third port 23 is blocked, the first coolant may be introduced into the fuel cell stack 10 , whereas when the third port 23 is open and the second port 22 is blocked, the first coolant may be introduced into the heater 50 through the first connection line 130 .

[0041] The first connecting line 130 can 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 connecting line 130 can be heated while passing through the heater 50 installed in the first connecting line 130. One end of the first connecting line 130 can be connected to the first cooling line 110 at a first point between the outlet of the first pump 30 and the fuel cell stack 10, and the other end of the first connecting line 130 can be connected to the first cooling line 110 at a second point between the inlet of the first pump 30 and the fuel cell stack 10. Here, the inlet of the first pump 30 can be defined as the inlet through which the first coolant is introduced into the first pump 30. In addition, the outlet of the first pump 30 can be defined as the outlet through which the first coolant passing through the first pump 30 is discharged. In addition, the portion between the outlet of the first pump 30 and the fuel cell stack 10 can be defined as the portion where the first coolant discharged from the first pump 30 flows to the first coolant inlet (not shown) of the fuel cell stack 10. In addition, a portion between the inlet of the first pump 30 and the fuel cell stack 10 may be defined as a portion where the first coolant discharged from a coolant outlet (not shown) of the fuel cell stack 10 flows toward the inlet of the first pump 30 .

[0042] The first pump 30 may be configured to force the first coolant to flow. The first pump 30 may include various devices that can pump the first coolant, and the type and number of the first pump 30 are not limited in the present disclosure.

[0043] The second valve 40 can switch the flow path of the first coolant to the first radiator 60 or the fuel cell stack 10 on the first cooling line 110. For example, the second valve 40 can be provided on the first cooling line 110 so as to be located between the first pump 30 and the first radiator 60, and can be connected to one end of the third connecting line 140 and the outlet of the first radiator 60. The second valve 40 can include various valve devices that can selectively switch the flow path of the first coolant to the first radiator 60 or the fuel cell stack 10. As an example, the second valve 40 can be a four-way valve or a three-way valve. If the second valve 40 is a three-way valve, it can include a first port 41 connected to the third connecting line 140, a second port 42 connected to the first cooling line 110, so that the first coolant passing through the first radiator 60 is introduced therein, and a fourth port 44 connected to the first cooling line 110, so that the first coolant is introduced into the first pump 30. If the second valve 40 is a four-way valve, it can further include a third port 43 connected to one end of the second connecting line 150. As the first port 41 or the second port 42 of the second valve 40 is opened and closed, the flow path of the first coolant can be switched to the first radiator 60 or the fuel cell stack 10. That is, when the first port 41 is open and the second port 42 is blocked, the first coolant is introduced into the fuel cell stack 10 without passing through the first radiator 60. Conversely, when the second port 42 is open and the first port 41 is blocked, the first coolant can be introduced into the fuel cell stack 10 after passing through the first radiator 60.

[0044] The second connecting line 150 can form a heating loop with the first cooling line 110 to heat the air conditioning unit (HVAC unit) 90. As an example, the second connecting line 150 can form a loop to heat a heater (not shown) used to heat the air conditioning unit 90. One end of the second connecting line 150 can be connected to the first cooling line 110 between a first point (the point where one end of the first connecting line 130 is connected to the first cooling line 110) and the inlet of the fuel cell stack 10, and a portion of the first coolant can circulate through the second connecting line 150. The other end of the second connecting line 150 can be connected to the first cooling line 110 between the first pump 30 and a second point (the point where the other end of the first connecting line 130 is connected to the first cooling line 110).

[0045] An ion filter 95 that filters ions of the first coolant passing through the air conditioning unit 90 can be provided in the second connecting line 150. Since current flows in the first coolant, causing the fuel cell stack 10 to short-circuit, or when the conductivity of the first coolant increases due to corrosion or seepage of the system, current flows to the first coolant, so the first coolant must maintain low conductivity. The ion filter 95 can be configured to remove ions included in the first coolant to maintain the conductivity of the first coolant at a specific level or lower. In this way, during a cold start, the supply of the first coolant flowing to the fuel cell stack 10 is interrupted (the second port 22 of the first valve 20 is blocked), the first coolant circulates via the heater 50 of the first connecting line 130 (warming loop), and also circulates along the second connecting line 150, thereby, during a cold start, it can be filtered (removing ions included in the first coolant) by the ion filter 95 provided in the second connecting line 150. Therefore, it is advantageous to maintain the conductivity of the first coolant introduced into the fuel cell stack 10 immediately after a cold start at a specific level or lower.

[0046] The third connecting line 140 can form a cooling loop with the first cooling line 110 to cool the first coolant. As an example, one end of the third connecting line 140 can 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 can be connected to the first cooling line 110 between the coolant outlet of the fuel cell stack 10 and the first radiator 60.

[0047] The first radiator 60 may be configured to cool the first coolant. The first radiator 60 may have various structures that can cool the first coolant, and the type and structure of the first radiator 60 are not limited or defined in the present disclosure. The first radiator 60 may be connected to a first reservoir 62 in which the first coolant is stored.

[0048] 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 the first point (the first valve 20), a second temperature sensor 114 that measures the temperature of the first coolant between the other end of the first connecting line 130 and the first pump 30, and a third temperature sensor 116 that measures the temperature of the coolant in the heater 50. In addition, the fuel cell system may include a fourth temperature sensor 118 that measures the temperature of the first coolant at the outlet of the first radiator 60. The fuel cell system may control the flow rate of the first coolant introduced into the fuel cell stack 10 based on the temperatures measured by the first temperature sensor 112, the second temperature sensor 114, the third temperature sensor 116, and the fourth temperature sensor 118. As an example, when the measured temperature of the first coolant circulating along the first cooling line 110 is lower than a preset target temperature, the flow rate of the introduced first coolant may be controlled to be lower than a predetermined flow rate. In this way, because the flow rate of the first coolant introduced into the fuel cell stack 10 is controlled to be low when the measured temperature of the first coolant is low, the thermal impact or performance degradation caused by the deviation between the temperature of the first coolant remaining inside the fuel cell stack 10 and the temperature of the first coolant introduced into the fuel cell stack 10 can be advantageously minimized.

[0049] The second cooling line 120 passes through the power electronic component 200, and the second coolant can circulate along the second cooling line 120. Here, the power electronic component 200 of the vehicle can be understood as a component that uses the power supply of the vehicle as an energy source, and the type and number of the power electronic component 200 are not restricted or limited in the present disclosure. As an example, the power electronic component 200 may include at least any one of the following: a bidirectional high-voltage DC-DC converter (BHDC) 210 provided between the fuel cell stack 10 and the high-voltage battery (not shown) of the vehicle; a blower pump control unit (BPCU) 220 that controls a blower (not shown) that supplies external air to drive the fuel cell stack 10; a low-voltage DC-DC converter 230 that converts the DC high voltage received from the high-voltage battery into a DC low pressure; an air compressor (ACP) 240 that compresses the air supplied to the fuel cell stack 10; and an air cooler 250. Although Figure 1 and Figure 2 Not shown in FIG, the power electronic component 200 may further include a DC-DC buck / boost converter.

[0050] The second pump 205 for forcibly flowing the second coolant may be disposed on the second cooling line 120. The second pump 205 may include a pumping device that can pump the second coolant, and the type and features of the second pump 205 are not limited or restricted.

[0051] The second radiator 70 for cooling the second coolant may be arranged on the second cooling line 120. The second radiator 70 may have various structures that can cool 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.

[0052] In this embodiment, if Figure 1 As shown, the first radiator 60 and the second radiator 70 can be cooled simultaneously by a single cooling fan 80. As an example, the first radiator 60 and the second radiator 70 can be arranged in parallel, and the cooling fan 80 can be configured to blow external air toward the first radiator 60 and the second radiator 70. Since the first radiator 60 and the second radiator 70 are cooled simultaneously by a single cooling fan 80, the structure of the fuel cell system can be simplified, the degree of freedom in design and space utilization can be improved, and the power consumption for cooling the first radiator 60 and the second radiator 70 can be minimized.

[0053] In another embodiment, Figure 2 As shown, the first cooling fan 80 for cooling the first radiator 60 and the second cooling fan 85 for cooling the second radiator 70 can be arranged separately. In this case, when controlling the RPM of the first cooling fan, the fuel cell system can exclude parameters related to the heat load of the power electronic component 200. The embodiment described below is based on Figure 1 The structure of the fuel cell system, but the same principle can be applied to Figure 2 The structure of the fuel cell system.

[0054] The heat exchanger 300 can be configured to exchange heat between the first coolant and the second coolant. When the heat exchanger 300 is included, the first cooling line 110 and the second cooling line 120 can constitute a thermal management system (TMS) line, in which the first coolant and the second coolant can flow while exchanging heat, and in this case, the first coolant or the second coolant can be used as a cooling medium or a heat medium on the TMS line. For example, because the temperature of the second coolant for cooling the power electronic components is lower than the temperature of the first coolant for cooling the fuel cell stack 10, the fuel cell system can advantageously reduce the temperature of the first coolant by heat exchange between the first coolant and the second coolant without increasing the capacity of the first radiator 60 and the cooling fan 80, which can improve the cooling efficiency of the fuel cell stack 10 and improve safety and reliability. In addition, because the fuel cell system can reduce the temperature of the first coolant when a vehicle that cannot use driving wind (e.g., a construction machine) stops, it is advantageous to ensure high output drive of the fuel cell stack 10 and improve safety and durability.

[0055] In an embodiment, a heat exchanger 300 may be connected to the first cooling line 110 between the outlet of the first radiator 60 and the fuel cell stack 10, and a second cooling line 120 may connect the outlet of the second radiator 70 and the power electronic components to pass through 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 interior of the heat exchanger 300 to be exposed to the first coolant (e.g., the first coolant flows along the circumference of the second cooling line 120). In this manner, the fuel cell system can reduce the temperature of the first coolant introduced into the fuel cell stack 10 through 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 coolant may be about 10° C. higher than the second temperature of the second coolant, and the third temperature of the first coolant passing through the heat exchanger 300 (exchanging heat with the second coolant) may be 1° C. lower than the first temperature.

[0056] according to Figure 1 and Figure 2 The heat exchanger 300 is arranged separately from the first radiator 60, but in another embodiment, the heat exchanger 300 can be directly connected to the first radiator 60. For example, the heat exchanger 300 can be connected to a specific position (upper left end) of the first radiator 60, but the present disclosure is not limited thereto.

[0057] In the case of the first cooling line 110 (in which the first coolant flows), the fuel cell system can measure the first coolant temperature at the inlet of the fuel cell stack 10 by the first temperature sensor 112, and can control the RPM of at least one of the first pump 30 and the cooling fan 80 so that the measured first coolant temperature reaches the target temperature. However, due to the large variation in the RPM of the first pump 30 and the cooling fan 80, it may be difficult to narrow the difference between the temperature measured by the first temperature sensor 112 and the target temperature. The fuel cell system according to the embodiment can accurately control the first coolant temperature to the target temperature by adjusting the opening of the second valve 40. In addition, the fuel cell system according to the embodiment can more accurately control the first coolant temperature by adjusting the opening of the second valve 40 using the first coolant temperature at the outlet of the fuel cell stack 10 measured by the second temperature sensor 114 and the first coolant temperature at the outlet of the first radiator 60 measured by the fourth temperature sensor 118.

[0058] Figure 3 A block diagram of a fuel cell system according to various embodiments is shown, wherein a first coolant flows, and Figures 4A to 4CThe coolant flow according to the opening degree of the valve is shown. Figure 3 In the configurations shown, the configurations with the same reference numerals perform the same Figure 1 or Figure 2 The configurations shown have the same functions, and their repeated descriptions will be omitted.

[0059] refer to Figure 3 , m represents the flow rate of the first coolant. For example, m1 may represent the flow rate of the first coolant flowing out of the fuel cell stack 10 and entering the second valve 40 without passing through the first radiator 60, m2 may represent the flow rate of the first coolant flowing out of the fuel cell stack 10 and entering the second valve 40 after passing through the first radiator 60, m3 may represent the flow rate of the first coolant entering the fuel cell stack 10 and flowing out of the second valve 40, m4 may represent the flow rate of the first coolant flowing out of the first valve 20 and entering the first pump 30 via the ion filter 95, and m5 may represent the flow rate of the first coolant flowing out of the first pump 30 and passing through the first valve 20. In addition, T represents the temperature of the first coolant. For example, T1 may represent the temperature of the first coolant at the outlet of the fuel cell stack 10, T2 may represent the temperature of the first coolant at the outlet of the first radiator 60, T3 may represent the temperature of the coolant at the inlet of the fuel cell stack 10, and T4 may represent the temperature of the first coolant passing through the heater 50. The flow rate and temperature of the first coolant can be expressed by Equation 1.

[0060] Equation 1

[0061] m3=m1+m2

[0062] m5=m3+m4

[0063] T2≤T3≤T1

[0064] The fuel cell system can adjust the ratio of the mixed first coolant and the temperature of the first coolant by adjusting the opening of the second valve 40. For example, Figure 4A The locked (closed) state (opening = 0) of the second valve 40 is shown, and in this case, since the second port 42 of the second valve 40 is closed, the first coolant flowing out of the fuel cell stack 10 can flow on the third connecting line 140 without passing through the first radiator 60. Figure 4B A state in which the second valve 40 is partially opened (0 < opening degree < 1) is shown, and in this case, since the first port 41 and the second port 42 of the second valve 40 are partially opened, a portion of the first coolant flows on the third connecting line 140 and the remaining portion thereof can pass through the first radiator 60. Figure 4CThe fully open (completely open) state (opening degree=1) of the second valve 40 is shown, and in this case, since the first port 41 of the second valve 40 is closed, all the first coolant flowing out of the fuel cell stack 10 can pass through the first radiator 60.

[0065] The first coolant temperature T1 at the inlet of the fuel cell stack 10 can be expressed by Equation 2.

[0066] Equation 2

[0067] T3=T1(1-OR)+C k T2OR

[0068] In Equation 2, the opening ratio (OR) represents the opening degree of the second valve 40. K The correction coefficient may be used to determine the opening of the second valve 40. The fuel cell system may determine the opening of the second valve 40 by setting the correction coefficient so that the first cooling temperature T3 at the inlet of the fuel cell stack 10 may reach the target temperature more accurately.

[0069] The fuel cell system can calculate the opening degree (OR) of the second valve 40 by equation 3 so that T3 can meet the target temperature T 3c .

[0070] Equation 3

[0071] OR=(T1-T 3c ) / (T1-C k T2)

[0072] Figure 5 A block diagram of a fuel cell system according to various embodiments is shown. Figure 5 The configuration shown may be a hardware device or a program (or application) including instructions.

[0073] refer to Figure 5 The first temperature sensor 512, the second temperature sensor 514 and the third temperature sensor 516 may have Figure 1 The first temperature sensor 112, the second temperature sensor 114 and the fourth temperature sensor 118 have the same or similar structures and can perform the same or similar functions. The valve 532, the pump 534 and the cooling fan 536 can have the same or similar structures as the first temperature sensor 112, the second temperature sensor 114 and the fourth temperature sensor 118 respectively. Figure 1 The second valve 40 , the first pump 30 , and the cooling fan 80 may have the same or similar structures and may perform the same or similar functions.

[0074] The controller 520 may be a hardware device, such as a processor or a central processing unit (CPU), or a program implemented by a processor. The controller 520 may be connected to a plurality of sensors 512, 514, and 516, a valve 532, a pump 534, and a cooling fan 536, and may perform the overall functions of the fuel cell system to control the coolant temperature. To implement this, the controller 520 may include a correction coefficient setter 522, an opening calculator 524, a valve controller 526, a pump controller 528, and a cooling fan controller 530. The configurations included in the controller 520 may exist separately or may be implemented by one integrated module.

[0075] The correction coefficient setter 522 may set a correction coefficient for controlling the opening of the valve 532. For example, the correction coefficient setter 522 may set an initial value of the correction coefficient to 1, and may adjust the correction coefficient based on a difference between the coolant temperature at the inlet of the fuel cell stack 10 measured by the first temperature sensor 512 and a target temperature.

[0076] The opening calculator 524 can calculate the opening of the valve 532 based on the coolant temperature at the outlet of the fuel cell stack 10 measured by the second temperature sensor 514, the coolant temperature at the outlet of the first radiator 60 measured by the third temperature sensor 516, a preset target temperature, and a correction coefficient. For example, the opening calculator 524 can calculate the opening of the valve 532 by using the above-mentioned equation 3.

[0077] The valve controller 526 may adjust the opening of the valve 532 according to the opening determined by the opening calculator 524 , and the pump controller 528 and the cooling fan controller 530 may control the RPMs of the pump 534 and the cooling fan 536 , respectively.

[0078] Figure 6 A flowchart illustrating operations for controlling the opening degree of a valve and a correction coefficient according to various embodiments is shown. The operations described below may be implemented by the fuel cell system, or may be implemented by a configuration (eg, controller 520) included in the fuel cell system.

[0079] Reference Figure 6 In operation 610 , the controller 520 may set a target temperature at the inlet of the fuel cell stack 10 and a correction coefficient for controlling the opening degree of the valve 532 .

[0080] In operation 620 , the controller 520 may measure the coolant temperature at the outlet of the fuel cell stack 10 (hereinafter referred to as “first coolant temperature”) and the coolant temperature at the outlet of the first radiator 60 (hereinafter referred to as “second coolant temperature”).

[0081] In operation 630 , the controller 520 may calculate an opening degree of the valve based on the first coolant temperature, the second coolant temperature, the target temperature, and the correction coefficient.

[0082] In operation 640, when the calculated opening is within a specific range (e.g., greater than 0 and not greater than 1), the controller 520 may correct the correction coefficient based on a comparison of the coolant temperature at the inlet of the fuel cell stack (hereinafter referred to as the "third coolant temperature") with the target temperature.

[0083] Figure 7 A flowchart illustrating detailed operations for controlling the opening degree of a valve and a correction coefficient according to various embodiments is shown.

[0084] refer to Figure 7 In operation 705, the controller 520 may set a correction coefficient. For example, the controller 520 may set an initial value of the correction coefficient to 1.

[0085] In operation 710 , the controller 520 may set a target temperature and measure a first coolant temperature and a second coolant temperature.

[0086] In operation 715 , the controller 520 may calculate an opening degree of the valve 532 based on the first and second coolant temperatures, the target temperature, and the correction coefficient.

[0087] In operation 720 , the controller 520 may identify whether the calculated opening degree is greater than 1.

[0088] When the opening degree is greater than 1, the controller 520 can no longer control the third cooling temperature to the target temperature through the opening degree of the valve 532 , and thus may control the RPMs of the pump 534 and the cooling fan 536 in operation 725 .

[0089] When the opening degree is not greater than 1, the controller 520 may determine whether the opening degree is 0 in operation 730. When the opening degree is 0, the controller 520 may repeat operations 705 to 720 without opening the valve 532 (closed state). For example, when the fuel cell system is in the initial temperature increase state, the third coolant temperature is lower than the target temperature, and therefore the controller 520 does not need to open the valve 532.

[0090] When the opening degree is not greater than 1 and is not 0, the controller 520 may determine whether the third coolant temperature is the same as the target temperature in operation 735. As another example, the controller 520 may determine whether the difference between the third coolant temperature and the target temperature is within a specific range (e.g., 1%), even if they are not the same. When the third coolant temperature is the same as the target temperature or the difference between the third coolant temperature and the target temperature is within a specific range, the controller 520 may repeat operations 705 to 720 without correcting the correction coefficient.

[0091] When the difference between the third coolant temperature and the target temperature deviates from a specific range, the controller 520 may identify whether the target temperature is higher than the temperature of the third coolant in operation 740. When the target temperature is higher, the controller 520 may reduce the correction coefficient (operation 745), and when the target temperature is lower, the controller 520 may increase the correction coefficient (operation 750).

[0092] One of the functions of a thermal management system is to regulate the temperature of the coolant introduced into the fuel cell stack inlet to a target temperature by discharging the heat generated in the fuel cell stack to the atmosphere through a radiator. Controlling the RPM of the pump and cooling fan to regulate the coolant temperature to the target temperature is a key issue. However, due to the large variations in the RPM of the pump and cooling fan, more precise control is required to reduce the difference between the coolant temperature and the target temperature. According to embodiments of the present disclosure, a fuel cell system can more precisely control the coolant temperature by adjusting the valve opening.

[0093] According to an embodiment of the present disclosure, a fuel cell system can more quickly adjust the coolant temperature at the inlet of a fuel cell stack to a target temperature.

[0094] According to an embodiment of the present disclosure, a fuel cell system can control coolant temperature through complex control of a pump, a cooling fan, and a valve while rapidly responding to changes in load.

[0095] Although the present disclosure includes specific examples, it will be apparent after an understanding of the disclosure of this application that various changes in form and detail can be made in these examples without departing from the spirit and scope of the claims and their equivalents. The examples described herein are to be considered descriptive only and not for purposes of limitation. The description of features or aspects in each example should be considered applicable to similar features or aspects in the other examples. Suitable results can be achieved if the described techniques are performed in a different order, and / or if the components in the described systems, architectures, devices, or circuits are combined in a different manner, and / or replaced or supplemented by other components or their equivalents. Accordingly, the scope of the present disclosure is not limited by the detailed description, but by the claims and their equivalents, and all variations within the scope of the claims and their equivalents should be construed as included in the present disclosure.

Claims

1. A temperature control device for a fuel cell system, comprising: fuel cell stacks; a first cooling line configured to circulate a first coolant through the fuel cell stack; a first radiator disposed on the first cooling line and configured to cool the first coolant; a valve configured to switch a flow path of the first coolant to the fuel cell stack or the first radiator; as well as A controller is connected to the valve, the controller being configured to: setting a target temperature at an inlet of the fuel cell stack and a correction coefficient for controlling an opening of the valve; measuring a first coolant temperature at an outlet of the fuel cell stack and a second coolant temperature at an outlet of the first radiator; measuring a third coolant temperature at an inlet of the fuel cell stack; calculating the opening of the valve based on the first coolant temperature, the second coolant temperature, the target temperature, and the correction coefficient; as well as In response to the opening degree being within a first range, the correction coefficient is corrected based on a comparison of the third coolant temperature at the inlet of the fuel cell stack with the target temperature.

2. The device according to claim 1, wherein The controller is further configured to: setting the correction coefficient to a previous value in response to a difference between the third coolant temperature and the target temperature being within a second range; decreasing the correction coefficient in response to the difference between the third coolant temperature and the target temperature deviating from the second range and the target temperature being higher than the third coolant temperature; as well as In response to the difference between the third coolant temperature and the target temperature deviating from the second range and the target temperature being lower than the third coolant temperature, the correction coefficient is increased.

3. The apparatus according to claim 1, further comprising: a first temperature sensor, arranged at the inlet of the fuel cell stack; a second temperature sensor, arranged at the outlet of the fuel cell stack; as well as A third temperature sensor is arranged at the outlet of the first radiator.

4. The apparatus according to claim 1, further comprising: a cooling fan disposed on the first cooling line and configured to blow external air to the first radiator; as well as a pump disposed on the first cooling line and configured to pump the first coolant; The controller is configured to control an RPM of at least one of the cooling fan and the pump in response to the opening degree deviating from the first range.

5. The device according to claim 4, wherein The controller is further configured to: and controlling the RPM of the cooling fan and the RPM of the pump so that, as the third coolant temperature reaches the target temperature, total power consumption becomes minimum by decreasing the RPM of the cooling fan and increasing the RPM of the pump, wherein the total power consumption is the sum of the power consumption corresponding to the RPM of the cooling fan and the power consumption corresponding to the RPM of the pump.

6. The device according to claim 4, wherein The controller includes: a valve controller configured to control the opening of the valve; a cooling fan controller configured to control the RPM of the cooling fan; and A pump controller is configured to control the RPM of the pump.

7. The device according to claim 6, wherein The valve controller, the cooling fan controller, and the pump controller are integrated into one module.

8. The apparatus according to claim 1, further comprising: a second cooling line configured to circulate a second coolant through the electrical component; a second radiator disposed on the second cooling line and configured to cool the second coolant; a heat exchanger configured to exchange heat between the first coolant and the second coolant; as well as A cooling fan is configured to cool any one or any combination of the first heat sink and the second heat sink.

9. A processor-implemented method for operating a fuel cell system including a fuel cell stack, the method comprising: setting a target temperature at an inlet of the fuel cell stack and a correction coefficient for controlling the opening of a valve; measuring a first coolant temperature at an outlet of the fuel cell stack and a second coolant temperature at an outlet of a first radiator; measuring a third coolant temperature at an inlet of the fuel cell stack; calculating the opening of the valve based on the first coolant temperature, the second coolant temperature, the target temperature, and the correction coefficient; as well as In response to the opening degree being within a first range, the correction coefficient is corrected based on a comparison of the third coolant temperature at the inlet of the fuel cell stack with the target temperature.

10. The method according to claim 9, wherein: The correction of the correction coefficient comprises: setting the correction coefficient to a previous value in response to a difference between the third coolant temperature and the target temperature being within a second range; reducing the correction coefficient in response to the difference between the third coolant temperature and the target temperature deviating from the second range and the target temperature being higher than the third coolant temperature; and In response to the difference between the third coolant temperature and the target temperature deviating from the second range and the target temperature being lower than the third coolant temperature, the correction coefficient is increased.

11. The method according to claim 9, further comprising: In response to the opening degree deviating from the first range, the RPM of any one or any combination of the cooling fan and the pump is controlled.

12. The method according to claim 11, wherein The control of the RPM includes: and controlling the RPM of the cooling fan and the RPM of the pump so that, as the third coolant temperature reaches the target temperature, total power consumption becomes minimum by decreasing the RPM of the cooling fan and increasing the RPM of the pump, wherein the total power consumption is the sum of the power consumption corresponding to the RPM of the cooling fan and the power consumption corresponding to the RPM of the pump.

13. A non-transitory computer-readable storage medium storing instructions that, when executed by a processor, cause the processor to perform the method according to claim 9.

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