Fuel cell system and method of controlling a heater of a fuel cell system

Abstract

The present disclosure relates to a fuel cell system and a method of controlling a heater of the fuel cell system. The fuel cell system according to the present disclosure includes a cathode oxygen depletion (COD) heater provided on a line through which a cooling water circulation flowing into a fuel cell stack passes, and heating the cooling water or consuming a residual power of the fuel cell stack, and a controller determining a power consumption according to a target heating amount of the COD heater, and controlling an operation of the COD heater based on the determined power consumption.

Description

TECHNICAL FIELD

[0001] The following description relates to a fuel cell system and a method of controlling a heater thereof. BACKGROUND

[0002] A fuel cell system can generate electric power using a fuel cell stack. For example, when hydrogen is used as a fuel of the fuel cell stack, the fuel cell stack can replace a solution to global environmental problems, and thus research and development on the fuel cell system has been continuously ongoing.

[0003] A fuel cell system can include a fuel cell stack that generates electric power, a fuel supply device that supplies a fuel (hydrogen) to the fuel cell stack, an air supply device that supplies oxygen in air as an oxidizer required for an electrochemical reaction to the fuel cell stack, and a thermal management system (TMS) that removes reaction heat of the fuel cell stack to the outside of the system, controls an operating temperature of the fuel cell stack, and performs a water management function.

[0004] The TMS is a cooling device that circulates an antifreeze solution as cooling water to the fuel cell stack to maintain an appropriate temperature (e.g., 60℃ to 70℃), and can include a TMS line through which the cooling water is circulated, a reservoir that stores the cooling water, a pump that circulates the cooling water, an ion filter that removes ions included in the cooling water, and a radiator that radiates heat of the cooling water to the outside. In addition, the TMS can include a heater (e.g., a cathode oxygen depletion (COD) heater) that heats the cooling water, an air conditioning device (e.g., a heater) that heats or cools an interior of a device (e.g., a vehicle) including the fuel cell system, etc. using the cooling water. The TMS can maintain components of the vehicle as well as the fuel cell stack at an appropriate temperature.

[0005] The TMS can use a heater to increase a temperature of the cooling water in the cell stack, or use an antifreeze solution for the fuel cell stack as the cooling water to secure cold startability. In this case, the cooling water of the TMS line serves as a cooling medium that cools the cell stack, and as a heating medium that is rapidly heated by the heater during a cold start, the cooling water is supplied to the cell stack, thereby increasing a temperature of the cell stack.

[0006] The COD heater is used to contribute to stability of the fuel cell stack by operating and consuming all of the electric power generated by the fuel cell stack in a shutdown mode as a vehicle operating termination mode, and to increase a temperature of the cooling water to a predetermined temperature so that the fuel cell stack can smoothly operate during an initial cold start in winter. However, the COD heater can control only an on / off operation. In this case, since the amount of heat generated is linearly determined according to the amount of electricity generated by the cell stack during the on / off operation, a target heat amount of the COD heater cannot be determined in a predetermined manner, and thus it is difficult to perform a specific thermal management control of the TMS. SUMMARY

[0007] This Summary is provided to introduce some aspects of some embodiments of the application in a simplified form. This Summary does not identify key or essential features of the claimed subject matter nor does it necessarily explain the scope of the claimed subject matter or the reason why modulating the power consumption of a cathode oxygen depletion (COD) heater is or will be desirable.

[0008] In one general aspect, a fuel cell system includes a cathode oxygen depletion (COD) heater disposed on a line through which a cooling water circulation flowing into a fuel cell stack passes and heating the cooling water or consuming a residual power of the fuel cell stack, and a controller configured to determine a power consumption based on a target heating amount of the COD heater and control an operation of the COD heater based on the determined power consumption.

[0009] In the cold start mode, the controller can be further configured to determine the power consumption based on a target heating amount for heating the cooling water until a cooling water temperature at an inlet of the fuel cell stack reaches a reference temperature.

[0010] The controller can be further configured to determine the power consumption as a maximum load of the COD heater.

[0011] When the cooling water temperature at the inlet of the fuel cell stack becomes greater than or equal to the reference temperature, the controller can be further configured to turn off the COD heater and release the cold start mode.

[0012] In the shutdown mode, the controller can be further configured to determine the power consumption based on a target heating amount for consuming the residual power of the fuel cell stack until an output voltage of the fuel cell stack becomes less than a reference voltage.

[0013] The controller can be further configured to determine the power consumption as a maximum load of the COD heater.

[0014] When the output voltage of the fuel cell stack becomes less than the reference voltage, the controller can be further configured to turn off the COD heater and release the shutdown mode.

[0015] The COD heater can include a heater coil, a heater controller controlling a heating operation of the heater coil, a first relay disposed on a first control line connected to the heater controller and interrupting a power supply through the first control line, and a second relay disposed on a second control line connected to the heater coil and interrupting a power supply through the second control line.

[0016] When entering the cold start mode or the shutdown mode, the controller can be further configured to control the second relay to turn off and then control the first relay to turn on.

[0017] The controller can also be configured to operate a heater protection logic before operating the COD heater when entering the cold start mode or the shutdown mode, and monitor an operation state of the COD heater based on the heater protection logic while the COD heater is operated.

[0018] The controller can also be configured to release a communication connection of the COD heater, and allow the COD heater to operate in a simple resistor mode when the communication state of the COD heater is poor.

[0019] The controller can also be configured to control the first relay to be turned off, and then control the second relay to be turned on when the COD heater operates in the simple resistor mode.

[0020] The controller can also be configured to control the COD heater to be turned on or turned off according to a heating amount of the COD heater when the COD heater operates in the simple resistor mode.

[0021] The controller can also be configured to turn off the COD heater according to the heater protection logic when an operation voltage of the COD heater exceeds a reference voltage range, the operation voltage of the COD heater is less than a lower limit voltage, or a temperature of the COD heater exceeds a reference temperature and the temperature is not controllable.

[0022] The controller can also be configured to adjust a power consumption of the COD heater when the temperature of the COD heater exceeds the reference temperature and the temperature is controllable.

[0023] The controller can also be configured to output the power consumption of the COD heater at a predetermined ratio with respect to a maximum load of the COD heater when the temperature of the COD heater being operated in the shutdown mode exceeds the reference temperature and the temperature is controllable.

[0024] In another general aspect, a method of controlling a heater of a fuel cell system includes determining a power consumption according to a target heating amount of a cathode oxygen depletion (COD) heater disposed on a line through which cooling water circulating into a fuel cell stack is circulated, and heating the cooling water or consuming a residual power of the fuel cell stack, and controlling an operation of the COD heater based on the determined power consumption.

[0025] The step of determining the power consumption can include determining the power consumption based on a target heating amount for heating the cooling water until a temperature of the cooling water at an inlet of the fuel cell stack reaches a reference temperature in a cold start mode.

[0026] The step of determining the power consumption can include determining the power consumption based on a target heating amount for consuming a residual power of the fuel cell stack until an output voltage of the fuel cell stack becomes less than a reference voltage in a shutdown mode.

[0027] Further, the method of controlling the heater according to one embodiment of the disclosure can further include operating a heater protection logic before the COD heater operates when entering the cold start mode or the shutdown mode, and monitoring an operating state of the COD heater based on the heater protection logic while the COD heater operates.

[0028] Other features and aspects will become apparent from the following detailed description, drawings and claims. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 is a view illustrating a fuel cell system according to one embodiment of the disclosure;

[0030] Figure 2A and Figure 2B is a view illustrating a first cooling water flow of a fuel cell system according to one embodiment of the disclosure;

[0031] Figure 3 is a view illustrating a fuel cell system according to another embodiment of the disclosure;

[0032] Figure 4 is a view illustrating a fuel cell system according to still another embodiment of the disclosure;

[0033] Figure 5A and Figure 5B is a view illustrating a first pipe and a second pipe according to various embodiments;

[0034] Figure 6 is a view illustrating a detailed configuration of a heater according to one embodiment of the disclosure;

[0035] Figure 7 is a view illustrating a control block diagram of a fuel cell system according to one embodiment of the disclosure;

[0036] Figure 8 , Figure 9 and Figure 10 is a view illustrating an operation flow of a method of controlling a heater of a fuel cell system according to one embodiment of the disclosure; and

[0037] Figure 11 , Figure 12 and Figure 13 is a view illustrating an operation flow of a method of controlling a heater of a fuel cell system according to another embodiment of the disclosure.

[0038] Throughout the drawings and detailed description, identical reference numerals indicate the same elements or similar elements. The drawings can not be to scale and the relative dimensions, proportions and descriptions of the elements in the drawings can be exaggerated for clarity, illustration and convenience. DETAILED DESCRIPTION

[0039] The following detailed description is presented to aid the reader in understanding the method, apparatus and / or system described herein. However, the method, apparatus and / or system described herein can be implemented in a variety of ways and the details described herein are merely for the purposes of illustration. For example, the order in which the operations are described is merely illustrative and the operations can be carried out in any order necessary to achieve the results described herein, except where the order is clearly indicated by a preceding or following operation or context allows for only one implementation. Furthermore, the description of the features of the application is merely provided for the purposes of clarity and conciseness, and the description of features known after understanding the disclosure of the present application can be omitted.

[0040] The features described herein can be embodied in different forms, and should not be construed as being limited to the examples described herein. Rather, the examples described herein are provided merely to illustrate some of the many possible ways of implementing the method, apparatus and / or system described herein, as will be apparent after understanding the disclosure of the present application.

[0041] Throughout the specification, when one element is described as being "on" or "connected to" or "coupled to" another element, it can be directly on, connected or coupled to the other element, or intervening elements can be present. In contrast, when an element is described as being "directly on," "directly connected to," or "directly coupled to" another element, there are no intervening elements present.

[0042] As used herein, the term "and / or" includes any one of the associated listed items, as well as any combination of any two or more of the associated listed items.

[0043] Although terms such as "first", "second" and "third" can be used herein to describe various components, assemblies, regions, layers or parts, these components, assemblies, regions, layers or parts are not limited by these terms. Rather, these terms are merely used to distinguish one component, one assembly, one region, one layer or one part from another component, another assembly, another region, another layer or another part. Thus, a first component, a first assembly, a first region, a first layer or a first part mentioned in the examples described herein can also be referred to as a second component, a second assembly, a second region, a second layer or a second part, without departing from the teachings of the examples.

[0044] For purposes of the description hereinafter, spatial or directional terms, such as "upper", "lower", "above", and "below", and the like, can be used with reference to the illustrated embodiment. Unless otherwise indicated, such terms are intended to encompass orthogonal orientations as well. Terms concerning attachments, coupling, and the like, such as "connected" and "coupled", are intended to be construed in a non-limiting sense to encompass a wide variety of attachments, couplings, and / or the like. As used herein, "connected" can mean directly connected, or indirectly connected via one or more other devices or connections. In addition, the singular forms "a", "an", and "the" are intended to include one or more of their respective items, unless the context clearly indicates otherwise. Furthermore, to the extent that the terms "including" and / or "containing" are used in the detailed description and / or claims, such terms are intended to be broad in scope and include the terms "consisting essentially of" and / or "consisting of".

[0045] The terminology used herein is for the purpose of describing various examples only and is not intended to be limiting of the disclosure. The use of the singular herein includes the plural unless the context clearly dictates otherwise. The terms "comprising", "comprises", and "including" are used herein to mean including, but not limited to.

[0046] The shapes illustrated in the drawings can vary due to manufacturing techniques and / or tolerances. Thus, the examples described herein are not limited to the specific shapes illustrated in the drawings, but include variations of the shapes that occur during manufacturing.

[0047] It will be apparent to those skilled in the art that features of the examples described herein can be combined in a variety of ways without departing from the disclosure. Furthermore, although the examples described herein have a variety of configurations, other configurations can be apparent or apparent upon implementation of the disclosure.

[0048] Figures 1 to 4 is a view showing a fuel cell system according to various embodiments; Figure 1 is a view showing a fuel cell system according to one embodiment of the disclosure; Figure 2A and Figure 2B is a view showing a first cooling water flow of a fuel cell system according to one embodiment of the disclosure; and Figure 3 and Figure 4 is a view showing a fuel cell system according to other embodiments.

[0049] Referring to Figure 1, the vehicle fuel cell system can include a first cooling line 110 through which first cooling water passing through the fuel cell stack 10 of the vehicle is circulated, and a second cooling line 120 through which second cooling water passing through the power electronics 200 of the vehicle is circulated. In one embodiment, the fuel cell system can further include a heat exchanger 300 that exchanges heat between the first cooling water and the second cooling water, but the heat exchanger 300 can be omitted.

[0050] The fuel cell system can include a first connection line 130, a second connection line 150, and a third connection line 140 to form a heating loop (heating circulation path or heating loop) with the first cooling line 110 or to form a cooling line with the first cooling line 110. The first cooling water can be cooled or heated while being circulated through the first connection line 130, the second connection line 150, or the third connection line 140. For example, in an initial start state of the vehicle, in order to secure cold startability, the first cooling line 110 can form a heating loop with the first connection line 130 and the third connection line 140 as shown in Figure 2A , and during driving, in order to discharge heat generated by the fuel cell stack 10 to the outside, the first cooling line 110 can form a cooling loop in which the first cooling water passes through the first radiator 60 as shown in Figure 2B . Although not shown in Figure 2A and Figure 2B , according to the amount of cooling required by the fuel cell system, a portion of the first cooling water can flow to the third connection line 140, and another portion of the first cooling water can pass through the first radiator 60. In another embodiment, when the temperature of the outside air is as high as a specified temperature, the first cooling line 110 does not form a heating loop, and the fuel cell system can secure startability by 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 through which the first cooling water is circulated.

[0051] The fuel cell stack 10 (or referred to as "fuel cell") can be formed in a structure capable of generating electric power by an oxidation-reduction reaction of a fuel (for example, hydrogen) and an oxidizer (for example, air). For example, the fuel cell stack 10 can include a membrane electrode assembly (MEA) in which a catalytic electrode layer in which an electrochemical reaction occurs is attached to both sides with respect to the center of an electrolyte membrane through which hydrogen ions move, a gas diffusion layer (GDL) that uniformly distributes reaction gas and transfers generated electric power, a gasket and a fastening mechanism that maintain gas tightness and proper fastening pressure of the reaction gas and the first cooling water, and a bipolar plate that moves the reaction gas and the first cooling water.

[0052] In the fuel cell stack 10, hydrogen gas as a fuel and air (oxygen) as an oxidizer are supplied to the anode and the cathode of the MEA through the passages of the bipolar plates. The hydrogen gas can be supplied to the anode, and the air can be supplied to the cathode. The hydrogen gas supplied to the anode is decomposed into hydrogen ions (protons) and electrons by the catalyst of the electrode layer disposed on both sides of the electrolyte membrane. Among them, only the hydrogen ions can be selectively transferred to the cathode through the electrolyte membrane as a positive ion exchange membrane, while the electrons can be transferred to the cathode through the GDL and the bipolar plate as a conductor. In the cathode, the hydrogen ions supplied through the electrolyte membrane and the electrons transferred through the bipolar plate can react with the oxygen in the air supplied to the cathode by the air supply device to generate water. As a result of the movement of the hydrogen ions occurring in this case, a flow of electrons through the external lead can occur, and an electric current can be generated by the flow of electrons.

[0053] The first valve 20 can switch the flow path of the first cooling water on the first cooling line 110 to the first connection line 130 provided with the heater 50 or 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 devices capable of selectively switching the flow path of the first cooling water. 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 so that the first cooling water pumped by the first pump 30 flows into the first cooling line, a second port 22 connected to the first cooling line 110 so that the first cooling water passing through the first valve 20 flows into the fuel cell stack 10, and a third port 23 connected to one end of the first connection line 130. As the second port 22 and the third port 23 of the first valve 20 are opened or closed, the flow path of the first cooling water can be switched to the heater 50 of the first connection 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 cooling water flows into the fuel cell stack 10, and, in contrast, when the third port 23 is open and the second port 22 is blocked, the first cooling water can flow into the heater 50 through the first connection line 130.

[0054] The first connection line 130 can form a heating circuit (heating circulation path) with the first cooling line 110 to heat the first cooling water. For example, the first cooling water flowing along the first connection line 130 can be heated while passing through the heater 50 installed in the first connection line 130. One end of the first connection 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 connection 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 an inlet through which the first cooling water flows into the first pump 30. Also, the outlet of the first pump 30 can be defined as an output end through which the first cooling water discharged from the first pump 30 is output. Also, the portion between the outlet of the first pump 30 and the fuel cell stack 10 can be defined as a portion through which the first cooling water discharged from the first pump 30 flows to the first cooling water inlet (not shown) of the fuel cell stack 10. Also, the portion between the inlet of the first pump 30 and the fuel cell stack 10 can be defined as a portion through which the first cooling water discharged from the cooling water outlet (not shown) of the fuel cell stack 10 flows to the inlet of the first pump 30.

[0055] The first pump 30 can be provided to forcibly flow the first cooling water. The first pump 30 can include various devices capable of pumping the first cooling water, and the type of the first pump 30 and the number of the first pump 30 are not limited to the present document.

[0056] The second valve 40 can switch a flow path of the first cooling water on the first cooling line 110 to 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 an outlet of the first radiator 60. The second valve 40 can include various valve devices capable of selectively switching the flow path of the first cooling water to the first radiator 60 or the fuel cell stack 10. For example, the second valve 40 can be a four-way valve or a three-way valve. In the case of the three-way valve, the second valve 40 can 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 cooling water passing through the first radiator 60 flows into the first cooling line, and a fourth port 44 connected to the first cooling line 110 so that the first cooling water flows into the first pump 30, and in the case of the four-way valve, the second valve 40 can further include a third port 43 connected to one end of the second connection line 150. As the first port 41 and the second port 42 of the second valve 40 are opened or closed, the flow path of the first cooling water 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 cooling water flows into the fuel cell stack 10 without passing through the first radiator 60, and conversely, when the second port 42 is open and the first port 41 is blocked, the first cooling water can flow into the fuel cell stack 10 after passing through the first radiator 60. According to the amount of opening of the second valve 40, a part of the first cooling water can pass through the first radiator 60, and another part of the first cooling water can flow along the third connection line 140.

[0057] The second connection line 150 can form a heating circuit with the first cooling line 110 to heat the air conditioning device 90. For example, the second connection line 150 can form a circuit of a heater (not shown) of the air conditioning device 90. One end of the second connection line 150 can be connected to the first cooling line 110 between the first point (a point at which one end of the first connection line 130 is connected to the first cooling line 110) and the inlet of the fuel cell stack 10, and a part of the first cooling water can be circulated through the second connection line 150. The other end of the second connection line 150 can be connected to the first cooling line 110 between the first pump 30 and the second point (a point at which the other end of the first connection line 130 is connected to the first cooling line 110).

[0058] The second connection line 150 can be provided with an ion filter 95 that filters ions of the first cooling water passing through the air conditioning device 90. When the electrical conductivity of the first cooling water increases due to corrosion or bleeding of the system, electric power flows to the first cooling water to cause short-circuiting of the fuel cell stack 10 or to cause current to flow to the first cooling water, and thus the first cooling water should be maintained to have low electrical conductivity. The ion filter 95 can be provided to remove ions contained in the first cooling water so that the electrical conductivity of the first cooling water can be maintained below a predetermined level. In this way, during a cold start in which the supply of the first cooling water to the fuel cell stack 10 is blocked (the second port 22 of the first valve 20 is blocked), the first cooling water is circulated (passes through a warming-up circuit) via the heater 50 of the first connection line 130 and at the same time is circulated along the second connection line 150. Thus, even in the cold start, the filtration (removal of ions contained in the first cooling water) by the ion filter 95 provided in the second connection line 150 can be performed. Accordingly, the electrical conductivity of the first cooling water flowing into the fuel cell stack 10 immediately after the cold start can be maintained below a certain level.

[0059] The third connection line 140 can form a circulation path with the first cooling line 110 so that the first cooling water flows into the fuel cell stack 10 without passing through the first radiator 60. Here, a portion of the first cooling water can be cooled via the first radiator 60 along the first cooling line 110, and another portion of the first cooling water can move along the third connection line 140. In this case, the first cooling water cooled by the first radiator 60 is merged with the first cooling water passing through the third connection line 140, and thus its temperature can increase. For example, one end of the third connection 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 connection line 140 can be connected to the first cooling line 110 between the cooling water outlet of the fuel cell stack 10 and the first radiator 60.

[0060] The first radiator 60 can be provided to cool the first cooling water. The first radiator 60 can be formed in various structures capable of cooling the first cooling water, and the present disclosure is not bound or limited by the type and structure of the first radiator 60.

[0061] The first radiator 60 can be connected to a first reservoir 62 that stores the first cooling water.

[0062] The fuel cell system can include a first temperature sensor 112 that measures a temperature of the first cooling water between the fuel cell stack 10 and a first point (the first valve 20), a second temperature sensor 114 that measures a temperature of the first cooling water between the other end of the first connection line 130 and the first pump 30, and a third temperature sensor 116 that measures a temperature of the first cooling water in the heater 50. The fuel cell system can control an inflow rate of the first cooling water 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, when the measured temperature of the first cooling water circulating along the first cooling line 110 is lower than a predetermined target temperature, the inflow rate of the first cooling water can be controlled to be lower than a preset inflow rate.

[0063] The second cooling line 120 can pass through the power electronics 200, and the second cooling water can circulate along the second cooling line 120. Here, the power electronics 200 of the vehicle can be understood as a component that uses the electric power of the vehicle as an energy source, and the present disclosure is not bound or limited by the type and number of the power electronics 200. For example, the power electronics 200 can include at least one of a bidirectional high voltage DC-DC converter (BHDC) 210 disposed between the fuel cell stack 10 and a 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 (LDC) 230 that converts a DC high voltage supplied from the high voltage battery into a DC low voltage, an air compressor (ACP) 240 that compresses air supplied to the fuel cell stack 10, and an air cooler 250. Although not shown in Figures 1 to 4 The power electronics 200 can further include a DC-DC step-down / step-up converter.

[0064] A second pump 205 for forcibly flowing the second cooling water can be provided on the second cooling line 120. The second pump 205 can include a pumping device capable of pumping the second cooling water, and the type and number of the second pump 205 are not limited to the present document.

[0065] A second radiator 70 for cooling the second cooling water can be provided on the second cooling line 120. The second radiator 70 can be formed in various structures capable of cooling the second cooling water, and the type and structure of the second radiator 70 are not bound or limited. The second radiator 70 can be connected to a second reservoir 72 that stores the second cooling water.

[0066] In one embodiment, as Figure 1As shown, the first radiator 60 and the second radiator 70 can be cooled simultaneously by one cooling fan 80. For example, the first radiator 60 and the second radiator 70 can be arranged side by side, and the cooling fan 80 can be provided 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 one cooling fan 80, the structure of the fuel cell system can be simplified, the degree of freedom of design and the space utilization can be improved, and the power consumption for cooling the first radiator 60 and the second radiator 70 can be minimized.

[0067] In another embodiment, as shown in FIG. 6, a first cooling fan 80 for cooling the first radiator 60 and a second cooling fan 85 for cooling the second radiator 70 can be arranged separately. In this case, when the fuel cell system controls the number of revolutions of the first cooling fan 80, a parameter related to the thermal load of the power electronics 200 can be excluded. Although the embodiment described below is based on the structure of the fuel cell system of Figure 3 , the same principle can be applied to the structure of the fuel cell system of Figure 1 . Figure 3

[0068] Referring back to Figure 1 , the heat exchanger 300 can be provided to exchange heat between the first cooling water and the second cooling water. 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 through which the first cooling water and the second cooling water flow while exchanging heat between each other, and in this case, the first cooling water or the second cooling water can be used as a cooling medium or a heating medium on the TMS line. For example, since the temperature of the second cooling water for cooling the power electronics is relatively lower than the temperature of the first cooling water for cooling the fuel cell stack 10, the fuel cell system can reduce the temperature of the first cooling water without increasing the capacity of the first radiator 60 and the cooling fan 80 by exchanging heat between the first cooling water and the second cooling water, can improve the cooling efficiency of the fuel cell stack 10, and can improve safety and reliability. In addition, since the fuel cell system can reduce the temperature of the first cooling water at the time when the vehicle (for example, a construction machine) that cannot use a driving wind stops, high output operation of the fuel cell stack 10 is ensured, and safety and durability are improved.

[0069] ​In one embodiment, the heat exchanger 300 can be 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 can be connected to the outlet of the second radiator 70 and the power electronics components to pass through the heat exchanger 300. For example, the first cooling water can flow along the heat exchanger 300 connected to the first cooling line 110, and the second cooling line 120 can pass through the inside of the heat exchanger 300 so that the second cooling line 120 is exposed to the first cooling water (e.g., the first cooling water flows along the periphery of the second cooling line 120). In this way, the fuel cell system can reduce the temperature of the first cooling water flowing into the fuel cell stack 10 by exchanging heat between the first cooling water and the second cooling water. The first temperature of the first cooling water passing through the first radiator 60 can be formed to be higher than the second temperature of the second cooling water passing through the second radiator 70, and the third temperature of the first cooling water passing through the heat exchanger 300 can be formed to be lower than the first temperature. For example, the first temperature of the first cooling water can be formed to be 10℃ higher than the second temperature of the second cooling water, and the third temperature of the first cooling water passing through the heat exchanger 300 (exchanged with the second cooling water) can be formed to be 1℃ lower than the first temperature.

[0070] According to Figures 1 to 3 the heat exchanger 300 can be provided separately from the first radiator 60, but as Figure 4 indicated, the heat exchanger 300 according to another embodiment can be directly connected to the first radiator 60. For example, the heat exchanger 300 can be connected to a designated position (the upper left end) of the first radiator 60, but the present disclosure is not limited thereto. When the heat exchanger 300 is connected to the upper left end of the first radiator 60, the first radiator 60 and the heat exchanger 300 can be implemented as Figure 5A and Figure 5B indicated.

[0071] Figure 5A and Figure 5B The first duct and the second duct according to various embodiments are described.

[0072] Referring to Figure 5A and Figure 5BThe first radiator 60 can include a first duct 64 forming a first flow path 64a through which the first cooling water flows, the heat exchanger 300 can include a second duct 302 disposed to exchange heat with the first cooling water inside the first flow path 64a, and the second cooling water can flow along the second duct 302 and exchange heat with the first cooling water in the first flow path 64a. The second duct 302 can form a second flow path 302a through which the second cooling water flows, and at least a portion of the second duct 302 can be exposed to the first cooling water inside the first flow path 64a. The shape and structure of the second duct 302 can be variously changed according to the required conditions and design specifications, and the present disclosure is not bound or limited by the shape and structure of the second duct 302. According to an embodiment, in order to improve the cooling effect of the first cooling water, a heat dissipation fin for increasing the contact area on the outer surface of the second duct exposed to the first cooling water can be formed. According to an embodiment, a sealing member 304 (e.g., rubber or silicone) can be provided between the first duct 64 and the second duct 302. In this way, since the sealing member 304 is provided between the first duct 64 and the second duct 302, the sealed state of the first flow path 64a can be more stably maintained.

[0073] In the case of a vehicle (e.g., construction machinery) requiring high power even at the time of stop, since the cooling performance of the power electronics part 200 should be ensured, the fuel cell system according to the embodiment can determine the number of revolutions of the second pump 205 in consideration of the number of revolutions of the cooling fan 80 or 85, the outside temperature, and the target cooling performance of the power electronics part 200. Further, the fuel cell system can determine the number of revolutions of the second pump 205 in consideration of at least one of the arrangement of the heat exchanger 300, the structure of the cooling fan (e.g., double or multiple), and the inflow air amount of the radiators 60 and 70, and thus, the cooling performance in the fuel cell system in which the first cooling line 110 and the second cooling line 120 coexist can be optimized.

[0074] Figure 6 FIG. 1 is a view showing a specific configuration of a heater according to an embodiment of the present disclosure.

[0075] Referring to Figure 6 The heater 50 is provided on the first connection line 130 connected to the first cooling line 110 through which the first cooling water circulates, and the heater 50 heats the first cooling water when the flow path of the first cooling water circulates along the first connection line 130. For example, when the first cooling water flows into the first connection line 130 during cold start, the heater 50 can heat the first cooling water introduced through the first connection line 130. In this case, the first cooling water heated by the heater 50 flows into the fuel cell stack 10 through the first cooling line 110 connected to the first connection line 130, and thus, cold startability can be ensured.

[0076] Here, the heater can be a cathode oxygen depletion (COD) heater in which a COD is coupled with the heater. The COD heater can be used as a heating device for heating the first cooling water to secure cold startability in winter, and can be used to consume the remaining electric power of the fuel cell stack to prevent a decrease in durability of the fuel cell stack during shutdown. Here, when the fuel cell vehicle is shut down, in order to prevent a decrease in durability of the fuel cell stack due to corrosion of the carbon-supported catalyst, the COD heater can consume electric power generated by the reaction of hydrogen and oxygen as heat in a state in which the COD is connected to both ends of the fuel cell stack, thereby removing residual oxygen in the fuel cell stack.

[0077] The COD heater can include a heater controller 52 that controls the operation of a heater coil 53 and controls the heater temperature, the heater coil 53 that generates heat based on electric power applied through a first control line 161 or a second control line 162, a first relay 51 that is disposed on the first control line 161 connected to the heater controller 52 and opens or closes a passage through which electric power generated by the fuel cell stack is applied to the heater controller 52, and a second relay 54 that is disposed on the second control line 162 connected to the heater coil 53 and opens or closes a passage through which electric power generated by the fuel cell stack is applied to the heater coil 53.

[0078] The first control line 161 can be connected to one end of the heater coil 53 through the first relay 51 and the heater controller 52. The second control line 162 can be connected to the other end of the heater coil 53 through the second relay 54. The first relay 51 and the second relay 54 are not turned on at the same time, and one relay is controlled to be turned off, and then the other relay can be controlled to be turned on.

[0079] The turn-on / turn-off operation of the first relay 51 and the second relay 54 can be controlled by a high-order controller (for example, a fuel cell system) of the COD heater.

[0080] Figure 7 FIG. 7 is a view showing a control block diagram of a fuel cell system according to one embodiment of the present disclosure.

[0081] Referring to Figure 7 , the fuel cell system can include a controller 710, a communication device 720, and a storage device 730.

[0082] The controller 710 can be a hardware device such as a processor or a central processing unit (CPU) or a program implemented by the processor. The controller 710 can be connected to various components of the fuel cell system and perform overall functions of the fuel cell system.

[0083] When switching to the cold start mode or the shutdown mode, the controller 710 controls a relay connected to a control line of the COD heater, and controls the operation of the COD heater. To this end, the controller 710 can include a mode setting device 711 which sets the cold start mode or the shutdown mode, a relay controller 713 which controls the first relay 51 and the second relay 54 of the COD heater, and a heater controller 715 which controls the operation of the COD heater during the cold start mode or the shutdown mode.

[0084] The components included in the controller 710 can be implemented as separate devices (or programs) or can be implemented in the form of one integrated module.

[0085] First, the mode setting device 711 can set the entry and release of the cold start mode. For example, the mode setting device 711 can set the entry of the cold start mode when there is a cold start mode entry request, and can set the release of the cold start mode when the inlet cooling water temperature condition of the fuel cell stack satisfies a standard condition.

[0086] Further, the mode setting device 711 can set the entry and release of the shutdown mode. For example, the mode setting device 711 can set the entry of the shutdown mode when there is a shutdown mode entry request, and can set the release of the shutdown mode when the output voltage condition of the fuel cell stack satisfies a standard condition.

[0087] Further, the mode setting device 711 can set or release the simple resistor mode of the COD heater. For example, when the communication connection is released due to a bad communication state of the COD heater, the mode setting device 711 can set the simple resistor mode of the COD heater. Of course, when the COD heater is normally operated, the mode setting device 711 can release the simple resistor mode.

[0088] When entering the cold start mode or the shutdown mode, the relay controller 713 can control the first relay 51 connected to the heater controller 52 and the second relay 54 directly connected to the heater coil 53 to be turned on / off according to the state of the COD heater.

[0089] For example, when entering the cold start mode, the relay controller 713 can control the second relay 54 to be turned off to block the power directly applied to the heater coil 53, and control the first relay 51 to apply the power through the heater controller 52. Here, the relay controller 713 can not simultaneously control the first relay 51 and the second relay 54, but can control the first relay 51 to be turned on after controlling the second relay 54 to be turned off.

[0090] Further, when the COD heater operates in the simple resistor mode due to the poor communication state of the COD heater, the relay controller 713 can control the first relay 51 to be turned off to block the application of power to the heater controller 52, and control the second relay 54 to directly apply power to the heater coil 53. Also, the relay controller 713 can not simultaneously control the first relay 51 and the second relay 54, but control the second relay 54 to be turned on after controlling the first relay 51 to be turned off.

[0091] The heater controller 715 determines the power consumption for operating the COD heater when entering the cold start mode or the shutdown mode, and controls the COD heater operation based on the determined power consumption. For example, when the COD heater operates in the cold start mode, the heater controller 715 can determine the power consumption of the COD heater as a maximum load so that the temperature of the first cooling water can reach the target cooling water temperature in the shortest time. Further, when the COD heater operates in the shutdown mode, the heater controller 715 can determine the power consumption of the COD heater as a maximum load so that the remaining power of the fuel cell stack can be consumed in the shortest time.

[0092] In this case, when the communication state of the COD heater is normal, when the heater controller 715 transmits the operation control signal to the heater controller 52, the heater controller 52 can control the operation of the heater coil 53 according to the operation control signal from the heater controller 715. Further, when the communication state of the COD heater is poor, the heater controller 715 can directly control the turn-on / off operation of the COD heater.

[0093] In the cold start mode, the COD heater heats the cooling water (i.e., the first cooling water) flowing into the fuel cell stack. In this case, the heater controller 715 identifies the cooling water temperature at the inlet of the fuel cell stack in real time while the COD heater operates, allows the COD heater to continuously operate until the cooling water temperature at the inlet of the fuel cell stack reaches a reference temperature, and turns off the COD heater when the cooling water temperature at the inlet of the fuel cell stack is greater than or equal to the reference temperature. In this case, the mode setting device 711 can release the cold start mode.

[0094] In the shutdown mode, the COD heater dissipates heat energy through the heater coil 53 to consume the remaining power of the fuel cell stack. In this case, the heater controller 715 identifies the output voltage of the fuel cell stack in real time while the COD heater operates, and turns off the COD heater when the output voltage of the fuel cell stack is less than a reference voltage. In this case, the mode setting device 711 can release the shutdown mode.

[0095] Before the COD heater operates, the heater controller 715 can operate the heater protection logic to protect the COD heater while the COD heater operates.

[0096] Here, the heater protection logic can include first heater protection logic 731 that monitors an operating voltage, a communication failure, and / or a temperature overheat of the COD heater based on a range between the upper limit voltage and the lower limit voltage in the cold start mode and protects the COD heater from a problem situation, and second heater protection logic 735 that monitors the operating voltage, the communication failure, and / or the temperature overheat of the COD heater based on the upper limit voltage range in the shutdown mode and protects the COD heater from the problem situation. The first heater protection logic 731 and the second heater protection logic 735 can be stored in the storage 730.

[0097] Therefore, when entering the cold start mode or the shutdown mode, the heater controller 715 can call and execute the first heater protection logic 731 or the second heater protection logic 735 stored in the storage 730, and detect and protect the operating state of the COD heater according to the executed heater protection logic. In this case, when a problem situation occurs while detecting the operating state of the COD heater, the heater controller 715 can shut down the COD heater or perform another operation.

[0098] For example, the heater controller 715 calls and executes the first heater protection logic 731 in the cold start mode, and monitors the operating state of the COD heater according to the first heater protection logic 731 while the COD heater operates.

[0099] In this case, the heater controller 715 can detect the operating voltage of the COD heater, and shut down the COD heater according to the first heater protection logic 731 when the operating voltage of the COD heater is greater than the upper limit voltage V H or less than the lower limit voltage V L .

[0100] Further, the heater controller 715 can monitor the communication state of the COD heater, and can disconnect the communication according to the first heater protection logic 731 when the communication state of the COD heater is poor. In this case, the heater controller 715 allows the COD heater to operate in a simple resistor mode. When the COD heater operates in the simple resistor mode, the heater controller 715 can increase the temperature of the first cooling water while controlling the on / off operation of the COD heater itself. When the cooling water temperature at the inlet of the fuel cell stack is greater than or equal to the reference temperature while the COD heater operates in the simple resistor mode, the heater controller 715 can turn off the COD heater. In this case, the mode setting device 711 can release the cold start mode.

[0101] Further, the heater controller 715 can monitor the temperature of the COD heater, and turn off the COD heater according to the first heater protection logic 731 when the temperature of the COD heater exceeds a reference temperature of Y °C and the temperature is not controllable. Accordingly, it is possible to prevent the COD heater from overheating. When the temperature of the COD heater exceeds the reference temperature of Y °C but the temperature is controllable, the heater controller 715 can adjust the power consumption of the COD heater according to the first heater protection logic 731 to prevent the COD heater from overheating.

[0102] For another example, the heater controller 715 invokes and executes the second heater protection logic 735 in the shutdown mode, and monitors the operation state of the COD heater according to the second heater protection logic 735 while the COD heater operates.

[0103] In this case, the heater controller 715 can detect the operating voltage of the COD heater, and turn off the COD heater according to the second heater protection logic 735 when the operating voltage of the COD heater is greater than an upper limit voltage V H

[0104] ​Further, the heater controller 715 can monitor a communication state of the COD heater, and when the communication state of the COD heater is poor, can disconnect the communication according to the second heater protection logic 735. In this case, the heater controller 715 allows the COD heater to operate in a simple resistor mode. When the COD heater operates in the simple resistor mode, the heater controller 715 can increase the temperature of the first cooling water while controlling the on / off operation of the COD heater itself. When the output voltage of the fuel cell stack is less than the reference voltage while the COD heater operates in the simple resistor mode, the heater controller 715 can turn off the COD heater. In this case, the mode setting device 711 can release the shutdown mode. As such, according to the present disclosure, even when a problem such as a communication failure occurs in the COD heater, power can be directly supplied to the heater coil 53 so that the COD heater operates as a simple resistor, and thus the fuel cell system can be stably operated without stopping.

[0105] Further, the heater controller 715 can monitor the temperature of the COD heater, and when the temperature of the COD heater exceeds a reference temperature of Y℃ and the temperature is not controllable, turn off the COD heater according to the second heater protection logic 735. Accordingly, it is possible to prevent the COD heater from overheating.

[0106] When the temperature of the COD heater exceeds the reference temperature of Y℃ but the temperature is controllable, the heater controller 715 can adjust the power consumption of the COD heater to output only a predetermined ratio of A% of the maximum load according to the second heater protection logic 735. Accordingly, while preventing the COD heater from overheating, the remaining power of the fuel cell stack is consumed, and thus it is possible to secure stability.

[0107] The communication device 720 can include a communication module that transmits / receives signals and / or data in the fuel cell system. For example, the communication module can receive information about the cooling water temperature at the inlet of the fuel cell stack from the temperature sensor, and receive information about the output voltage of the fuel cell stack 10. Further, while the COD heater operates in the cold start mode or the shutdown mode, the communication module can receive information about the operation state of the COD heater. Further, the communication module can transmit a control signal for driving the protection logic of the COD heater and / or a control signal for controlling the operation of the COD heater.

[0108] In this case, the communication module can communicate with each component constituting the fuel cell system using a vehicle network communication technology. Here, the vehicle network communication technology can include Controller Area Network (CAN) communication, Local Interconnect Network (LIN) communication, Bluetooth communication, etc.

[0109] The storage 730 can store data and / or algorithms required for operating the fuel cell system. For example, the storage 730 can store information about the state of the fuel cell stack and power electronics in the TMS. The storage 730 can store operation state information of the COD heater operating in the cold start mode or the shutdown mode. Further, the storage 730 can store protection logic such as the first heater protection logic 731 and the second heater protection logic 735 to protect the COD heater when the COD heater operates.

[0110] Here, the storage 730 can include a storage medium such as a random access memory (RAM), a static RAM (SRAM), a read only memory (ROM), a programmable ROM (PROM), and an electrically erasable programmable ROM (EEPROM).

[0111] The operation flow of the fuel cell system according to the present disclosure configured as above will be described more specifically below.

[0112] Figures 8 to 10 is a view showing an operation flow of a method of controlling a heater of a fuel cell system according to one embodiment of the present disclosure.

[0113] First, Figure 8 The operation flow of controlling the heater in the cold start mode is shown. Referring to Figure 8 When entering the cold start mode (S110), the fuel cell system controls the second relay 54 on the second control line 162 to be off (S120), and controls the first relay 51 on the first control line 161 to be on after the second relay 54 is off (S130). Here, the first control line 161 is a path connected to the heater coil 53 through the heater controller 52, and the power generated from the fuel cell stack is transmitted to the heater coil 53 through the path under the control of the heater controller 52. Further, the second control line 162 is a path directly connected to the heater coil 53, and the power generated from the fuel cell stack is directly transmitted to the heater coil 53 through the path. Therefore, as the first relay 51 is controlled to be on, the heater controller 52 is in a state where it can control the operation of the heater coil 53.

[0114] The fuel cell system controls the upper limit voltage V H and the lower limit voltage V Lthe COD heater (S140). Here, the fuel cell system can monitor an operating state of the COD heater while the COD heater is operated for the cold start based on the first heater protection logic 731 and determine whether the operating state of the COD heater satisfies a preset first shutdown condition. When the operating state of the COD heater satisfies the preset first shutdown condition, the fuel cell system can shut down the COD heater to protect the COD heater according to the first heater protection logic 731. Specific operations of the fuel cell system based on the first heater protection logic 731 will be described with reference to the embodiments of FIGS. 1 to 6. Figure 9

[0115] Thereafter, the fuel cell system determines a power consumption for operating the COD heater for the cold start (S150) and operates the COD heater based on the power consumption determined in operation S150 (S160). In operation S150, the fuel cell system can determine a power consumption required to raise a temperature of the first cooling water to be circulated along the first connection line and the first cooling line to a reference temperature. For example, the fuel cell system can operate the COD heater at a maximum load so that the temperature of the first cooling water can reach a target cooling water temperature in the shortest time.

[0116] The fuel cell system can identify a cooling water temperature at an inlet of the fuel cell stack while the COD heater is operated and can perform operation S160 until the cooling water temperature at the inlet of the fuel cell stack reaches a reference temperature of X℃.

[0117] When the cooling water temperature at the inlet of the fuel cell stack is greater than or equal to the reference temperature of X℃, the fuel cell system terminates the operation of the COD heater and exits the cold start mode (S180).

[0118] Figure 9 An operation flow of protecting the heater in the cold start mode is illustrated. Referring to Figure 9 , when the heater protection logic (e.g., the first heater protection logic 731) is operated in operation S140 of Figure 8 , the fuel cell system can monitor an operating state of the COD heater based on the first heater protection logic 731 while the COD heater is operated (S210).

[0119] First, the fuel cell system can monitor an operating voltage of the COD heater based on the first heater protection logic 731. In this case, when the operating voltage of the COD heater exceeds an upper limit voltage V H (S220), or when the operating voltage of the COD heater is less than a lower limit voltage V L ​At this time (S230), the fuel cell system can turn off the COD heater in accordance with the first heater protection logic 731 to prevent the COD heater from being damaged (S270).

[0120] Further, the fuel cell system can monitor a communication state of the COD heater based on the first heater protection logic 731. When the communication state of the COD heater is poor (S240), the fuel cell system can perform the operation S150 of Figure 10 after "A".

[0121] Further, the fuel cell system can monitor a temperature of the COD heater based on the first heater protection logic 731. When the temperature of the COD heater is lower than a reference temperature of Y℃ (S250), the fuel cell system can perform the operation S170 of Figure 8 while the COD heater is operated.

[0122] When the temperature of the COD heater exceeds the reference temperature of Y℃ (S250) but the temperature is controllable (S260), the fuel cell system can perform the operation S150 of Figure 8 to adjust the temperature of the COD heater and to adjust the power consumption of the COD heater in accordance with the first heater protection logic 731.

[0123] On the contrary, when the temperature of the COD heater exceeds the reference temperature of Y℃ (S250) and the temperature is not controllable (S260), the fuel cell system can turn off the COD heater to prevent the COD heater from overheating (S270) in accordance with the first heater protection logic 731.

[0124] Figure 10 An avoidance operation when the communication state of the COD heater is poor in the cold start mode is illustrated. Referring to Figure 10 When the communication state of the COD heater is poor, the fuel cell system retries the communication connection of the COD heater (S310), and then when the COD heater becomes communicable, performs the operation S150 (S320). Figure 8 of "A".

[0125] On the other hand, when the incommunicable state continues even after the communication connection of the COD heater is retried (S320), the fuel cell system releases the communication connection of the COD heater (S330) and allows the COD heater to operate in the simple resistor mode (S340). To this end, the fuel cell system controls the first relay 51 on the first control line 161 to turn off (S350), and controls the second relay 54 on the second control line 162 to turn on after the first relay 51 is turned off (S360).

[0126] When the second relay 54 is controlled to be turned on as the fuel cell stack's electric power is applied to the heater coil 53 of the COD heater through the second control line 162, the fuel cell system controls the turning on / off operation of the COD heater (S370). In this case, even when the COD heater cannot communicate, the heater coil 53 is configured as a simple resistor to control the turning on / off operation of the COD heater, so the fuel cell system can normally operate.

[0127] The operation S370 is performed until the cooling water temperature at the inlet of the fuel cell stack reaches the reference temperature of X℃, and when the cooling water temperature at the inlet of the fuel cell stack exceeds the reference temperature (S380), the fuel cell system turns off the COD heater and releases the cold start mode (S390).

[0128] Figures 11 to 13 is a view illustrating an operation flow of a method of controlling a heater of a fuel cell system according to another embodiment of the disclosure.

[0129] Figure 11 The control operation flow in the shutdown mode is illustrated. Referring to Figure 11 When entering the shutdown mode (S410), the fuel cell system controls the second relay 54 on the second control line 162 to be turned off (S420), and controls the first relay 51 on the first control line 161 to be turned on after the second relay 54 is turned off (S430). Here, the first control line 161 is a path connected to the heater coil 53 through the heater controller 52, and the electric power generated from the fuel cell stack is transmitted to the heater coil 53 through the path under the control of the heater controller 52. In addition, the second control line 162 is a path directly connected to the heater coil 53, and the electric power generated from the fuel cell stack is directly transmitted to the heater coil 53 through the path. Therefore, as the first relay 51 is controlled to be turned on, the heater controller 52 is in a state in which it can control the operation of the heater coil 53.

[0130] Thereafter, the fuel cell system operates the heater protection logic (e.g., the second heater protection logic 735) for the COD heater based on the preset range of the upper limit voltage V H Here, the fuel cell system can monitor the operation state of the COD heater based on the second heater protection logic 735 while the COD heater is operated for shutdown, and determine whether the operation of the COD heater satisfies the preset second turn-off condition. When the operation state of the COD heater satisfies the preset second turn-off condition, the fuel cell system can turn off the COD heater according to the second heater protection logic 735 to protect the COD heater. The specific operation of the fuel cell system based on the second heater protection logic 735 will be described with reference to the embodiment of Figure 12 .

[0131] Thereafter, the fuel cell system determines power consumption of the COD heater for shutdown operation (S450), and operates the COD heater based on the power consumption determined in operation S450 (S460). In operation S450, the fuel cell system can determine the power consumption of the COD heater based on the remaining power among the power generated by the fuel cell stack. For example, the fuel cell system can determine the power consumption of the COD heater as the maximum load to consume the remaining power of the fuel cell stack in the shortest time.

[0132] The fuel cell system can identify the output voltage of the fuel cell stack while the COD heater is operated, and perform operation S460 until the output voltage of the fuel cell stack reaches the reference voltage "Z".

[0133] When the output voltage of the fuel cell stack is less than the reference voltage "Z", the fuel cell system terminates the operation of the COD heater and exits the shutdown mode (S480).

[0134] Figure 12 An operation flow of protecting the heater in the shutdown mode is illustrated. Referring to FIG. 7, when the heater protection logic (e.g., the second heater protection logic 735) is operated in operation S440, the fuel cell system can monitor the operation state of the COD heater based on the second heater protection logic 735 while the COD heater is operated (S510). Figure 12

[0135] First, the fuel cell system can monitor the operating voltage of the COD heater based on the second heater protection logic 735. In this case, when the operating voltage of the COD heater exceeds the upper limit voltage V H (S520), the fuel cell system can turn off the COD heater to protect the COD heater based on the second heater protection logic 735 (S570).

[0136] Further, the fuel cell system can monitor the communication state of the COD heater based on the second heater protection logic 735. When the communication state of the COD heater is poor (S530), the fuel cell system can perform the operation of "B" after "A" of Figure 13

[0137] Further, the fuel cell system can monitor the temperature of the COD heater based on the second heater protection logic 735. When the temperature of the COD heater is lower than the reference temperature of Y℃ (S540), the fuel cell system can perform operation S470 of "C" after "B" of Figure 11

[0138] ​​​When the temperature of the COD heater exceeds the reference temperature of Y°C (S540) but the temperature is controllable (S550), the fuel cell system can output the power consumption of the COD heater at a predetermined ratio of A% with respect to the maximum load according to the second heater protection logic 735 to regulate the temperature of the COD heater (S560), and then perform Figure 11 operation S470.

[0139] On the other hand, when the temperature of the COD heater exceeds the reference temperature of Y°C (S540) and the temperature is not controllable (S550), the fuel cell system can turn off the COD heater according to the second heater protection logic 735 to prevent overheating of the COD heater (S570).

[0140] Figure 13 An avoidance operation when the communication state of the COD heater is poor in the shutdown mode is illustrated. Referring to Figure 13 , the fuel cell system retries the communication connection of the COD heater when the communication state of the COD heater is poor (S610), and then performs Figure 11 operation S460 (S620) when the COD heater becomes communicable.

[0141] On the other hand, when the incommunicable state continues even after the communication connection of the COD heater is retried (S620), the fuel cell system releases the communication connection of the COD heater (S630) and allows the COD heater to operate in the simple resistor mode (S640). To this end, the fuel cell system controls the first relay 51 on the first control line 161 to turn off (S650), and controls the second relay 54 on the second control line 162 to turn on after the first relay 51 is turned off (S660).

[0142] When the power of the fuel cell stack is applied to the heater coil 53 of the COD heater through the second control line 162 as the second relay 54 is controlled to turn on, the fuel cell system controls the on / off operation of the COD heater (S670). In this case, even when the COD heater cannot communicate, the heater coil 53 is configured as a simple resistor to control the on / off operation of the COD heater, so the fuel cell system can normally operate.

[0143] Operation S670 is performed until the output voltage of the fuel cell stack reaches the reference voltage "Z", and when the output voltage of the fuel cell stack becomes less than the reference voltage "Z" (S680), the fuel cell system turns off the COD heater and releases the shutdown mode (S690).

[0144] According to the disclosure, a cathode oxygen depletion (COD) heater is controlled in consideration of characteristics of a fuel cell stack in a cold start mode or a shutdown mode, and thus heat management control of a fuel cell system can be effectively operated.

[0145] Further, according to the disclosure, when a heater cannot be controlled due to a communication error of the heater, the heater is treated as a simple resistor to control operation of the heater, and thus heat management control of a fuel cell system can be stably operated.

[0146] The above description merely illustrates the technical spirit of the disclosure, and those skilled in the art to which the disclosure pertains can make various modifications and changes without departing from the essential characteristics of the disclosure.

[0147] One aspect of the disclosure provides a fuel cell system and a method of controlling a heater thereof, in which a cathode oxygen depletion (COD) heater is controlled in consideration of characteristics of a fuel cell stack in a cold start mode or a shutdown mode, and thus heat management control of a fuel cell system can be effectively operated.

[0148] Another aspect of the disclosure provides a fuel cell system and a method of controlling a heater thereof, in which when a heater cannot be controlled due to a communication error of the heater, the heater is treated as a simple resistor to control operation of the heater, and thus heat management control of a fuel cell system can be stably operated.

[0149] While the disclosure includes specific examples, it will be apparent after understanding the disclosure of the present application that various changes in form and details can be made to these examples without departing from the spirit and scope of the claims and their equivalents. The examples described herein are to be considered merely illustrative, and not restrictive, in nature. The description of features or aspects in each example is considered to apply to similar features or aspects in other examples. If the described techniques are performed in a different order, and / or if components in the described systems, architectures, devices, or circuits are combined and / or replaced by other components or their equivalents or supplemented with additional components, suitable results can be achieved. Therefore, the scope of the disclosure is not limited by the specific description, but by the claims and their equivalents, and all variations within the scope of the claims and their equivalents are to be construed as included in the disclosure.

[0150] Cross Reference to Related Applications

[0151] This application claims the benefit of Korean Patent Application No. 10-2021-0119084, filed September 7, 2021, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference for all purposes.

Claims

1. A fuel cell system, the fuel cell system comprising: A cathode oxygen-consuming COD heater, wherein the cathode oxygen-consuming COD heater is disposed on the pipeline through which the cooling water flowing into the fuel cell stack circulates, and is configured to heat the cooling water or consume the surplus power of the fuel cell stack; and A controller configured to determine power consumption based on the target heating capacity of the cathode oxygen-consuming COD heater, and to control the operation of the cathode oxygen-consuming COD heater based on the determined power consumption. When the communication status of the cathode oxygen-consuming COD heater is poor, the controller is also configured to disconnect the communication connection of the cathode oxygen-consuming COD heater and allow the cathode oxygen-consuming COD heater to operate in simple resistor mode.

2. The fuel cell system according to claim 1, wherein, In cold start mode, the controller is also configured to determine the power consumption based on a target heating amount used to heat the cooling water until the cooling water temperature at the inlet of the fuel cell stack reaches a reference temperature.

3. The fuel cell system according to claim 2, wherein, The controller is also configured to determine the power consumption as the maximum load of the cathode oxygen-consuming COD heater.

4. The fuel cell system according to claim 2, wherein, When the cooling water temperature at the inlet of the fuel cell stack becomes greater than or equal to the reference temperature, the controller is also configured to shut down the cathode oxygen-consuming (COD) heater and deactivate the cold start mode.

5. The fuel cell system according to claim 1, wherein, In shutdown mode, the controller is also configured to determine the power consumption based on a target heating amount used to consume the remaining power of the fuel cell stack until the output voltage of the fuel cell stack becomes less than a reference voltage.

6. The fuel cell system according to claim 5, wherein, The controller is also configured to determine the power consumption as the maximum load of the cathode oxygen-consuming COD heater.

7. The fuel cell system according to claim 5, wherein, When the output voltage of the fuel cell stack becomes less than the reference voltage, the controller shuts down the cathode oxygen-consuming (COD) heater and releases the shutdown mode.

8. The fuel cell system according to claim 1, wherein, The cathode oxygen-consuming COD heater includes: Heater coil; A heater controller configured to control the heating operation of the heater coil; A first relay, disposed on a first control line connected to the heater controller, and configured to interrupt the power supply through the first control line; and A second relay is disposed on a second control line connected to the heater coil and is configured to interrupt the power supply through the second control line.

9. The fuel cell system according to claim 8, wherein, When entering cold start mode or shutdown mode, the controller is also configured to control the second relay to turn off and then control the first relay to turn on.

10. The fuel cell system according to claim 9, wherein, When entering the cold start mode or the shutdown mode, the controller is also configured to operate the heater protection logic before operating the cathode oxygen-consuming COD heater, and to monitor the operating status of the cathode oxygen-consuming COD heater based on the heater protection logic while the cathode oxygen-consuming COD heater is operating.

11. The fuel cell system according to claim 10, wherein, When the cathode oxygen-consuming COD heater operates in the simple resistor mode, the controller is also configured to control the first relay to turn off and then control the second relay to turn on.

12. The fuel cell system according to claim 10, wherein, When the cathode oxygen-consuming COD heater operates in the simple resistor mode, the controller is also configured to control the on or off operation of the cathode oxygen-consuming COD heater based on the heating amount of the cathode oxygen-consuming COD heater.

13. The fuel cell system according to claim 10, wherein, When the operating voltage of the cathode oxygen-consuming COD heater exceeds the reference voltage range, the operating voltage of the cathode oxygen-consuming COD heater is less than the lower limit voltage, or the temperature of the cathode oxygen-consuming COD heater exceeds the reference temperature and the temperature is uncontrollable, the controller is also configured to shut down the cathode oxygen-consuming COD heater according to the heater protection logic.

14. The fuel cell system according to claim 10, wherein, When the temperature of the cathode oxygen-consuming COD heater exceeds a reference temperature and the temperature is controllable, the controller is also configured to adjust the power consumption of the cathode oxygen-consuming COD heater.

15. The fuel cell system according to claim 14, wherein, When the temperature of the cathode oxygen-consuming COD heater operating in the shutdown mode exceeds the reference temperature and the temperature is controllable, the controller is also configured to output the power consumption of the cathode oxygen-consuming COD heater at a predetermined ratio relative to the maximum load of the cathode oxygen-consuming COD heater.

16. A method for controlling a heater in a fuel cell system, the method comprising the steps of: The power consumption is determined based on the target heating amount of the cathode oxygen-consuming COD heater installed on the pipeline through which the cooling water flows into the fuel cell stack, and the cooling water is heated or the remaining power of the fuel cell stack is consumed. as well as The operation of the cathode oxygen-consuming COD heater is controlled based on the determined power consumption. The method further includes: when the communication status of the cathode oxygen-consuming COD heater is poor, disconnecting the communication connection of the cathode oxygen-consuming COD heater and allowing the cathode oxygen-consuming COD heater to operate in simple resistor mode.

17. The method according to claim 16, wherein, The step of determining the power consumption includes the following steps: in cold start mode, determining the power consumption based on a target heating amount used to heat the cooling water until the cooling water temperature at the inlet of the fuel cell stack reaches a reference temperature.

18. The method according to claim 16, wherein, The step of determining the power consumption includes the following steps: in shutdown mode, determining the power consumption based on a target heating amount for consuming the remaining power of the fuel cell stack until the output voltage of the fuel cell stack becomes less than a reference voltage.

19. The method of claim 16, further comprising the step of: When entering cold start mode or shutdown mode, the heater protection logic is activated before the cathode oxygen-consuming COD heater is operated. as well as While the cathode oxygen-consuming COD heater is operating, the operating status of the cathode oxygen-consuming COD heater is monitored based on the heater protection logic.

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