Fuel cell system and control method thereof

Abstract

The present invention relates to a fuel cell system and a method for controlling the same, comprising: a step in which a reformer generates a first gas using a first reaction with a fuel; a step in which a control unit determines a specific flow path among a first flow path bypassing a fuel cell stack and a second flow path connected to the fuel cell stack based on component ratio information of the first gas; and a step in which the control unit controls a valve to cause the first gas to flow through the specific flow path.

Description

Technology Field

[0001] The embodiments disclosed in this document relate to a fuel cell system and a method for controlling the same. Background Technology

[0002] A fuel cell system is an integrated system that generates electrical energy through the electrochemical reaction between hydrogen contained in the fuel and oxygen contained in the air, and various research and development are underway to replace fossil energy. As such, fuel cells have the advantage of lower emissions of pollutants and greenhouse gases compared to other energy media.

[0003] Fuel cells are classified into various types depending on the electrolyte or catalyst used, operating temperature, etc. For example, low-temperature fuel cells that operate at relatively low temperatures may include phosphoric acid fuel cells (PAFCs), and high-temperature fuel cells that operate at relatively high temperatures may include solid oxide fuel cells (SOFCs) and molten carbonate fuel cells (MCFCs).

[0004] In particular, solid oxide fuel cell systems have the advantage of high energy efficiency, so research is continuing to utilize them in various fields, such as ships.

[0005] A solid oxide fuel cell system undergoes a process of converting fuel (e.g., methane (CH4)) and water (H2O) into fuel required by a fuel cell stack (e.g., hydrogen, carbon monoxide, and some methane) by reforming them in a reformer.

[0006] At this time, since supplying the water required for reforming from an external water supply system increases the total surface area (or volume) required to operate the fuel cell system, a method is being discussed to recirculate the water generated through internal reforming and electrochemical reactions via an ejector for use in the reforming reaction.

[0007] During the initial startup phase of a fuel cell system, since there is insufficient water for reforming, a portion of air is supplied into the reformer to repeat the process of generating water through a partial oxidation reaction of the fuel (methane).

[0008] However, in conventional fuel cell systems, repeating the above process to generate the water required for reforming leads to a problem where the lifespan of the fuel cell stack is reduced. This is because carbon particles, generated along with water through the partial oxidation reaction of fuel and air, enter the fuel electrode of the fuel cell stack, causing carbon to be deposited on the electrode where the electrochemical reaction takes place.

[0009] Therefore, measures to solve the aforementioned problems are being studied. The problem to be solved

[0010] The embodiments disclosed in this document aim to provide a method and system for preventing carbon deposition at the fuel electrode of a fuel cell stack.

[0011] The embodiments disclosed in this document are intended to provide a method and system for increasing the lifespan of a fuel cell stack.

[0012] The technical problems of the present invention are not limited to those mentioned above, and other unmentioned technical problems will be clearly understood by those skilled in the art from the description below. means of solving the problem

[0013] A method according to one embodiment disclosed in this document may include: a step in which a reformer generates a first gas using a first reaction with a fuel; a step in which a control unit determines, based on component ratio information of the first gas, a specific flow path in which the first gas flows among a first flow path bypassing a fuel cell stack and a second flow path connected to the fuel cell stack; and a step in which the control unit controls a valve to cause the first gas to flow through the specific flow path.

[0014] In one embodiment, in the step of controlling the valve, the control unit controls the valve to cause the first gas to flow through the second flow path, and after the step of controlling the valve, the control unit may further include the step of determining a specific mode among a first mode in which the supply of the third gas to the reformer is maintained and a second mode in which the supply of the third gas to the reformer is cut off, based on component ratio information of the second gas generated from the reformer.

[0015] In one embodiment, the method may further include the step of determining the specific mode, wherein the control unit determines the second mode as the specific mode, and after the step of determining the specific mode, the reformer generates a fourth gas using a second reaction with respect to the fuel; and the fuel cell stack generates electrical energy using the third gas and the fourth gas.

[0016] In one embodiment, the first reaction may be a partial oxidation reaction that reacts the fuel and air, and the second reaction may be a reforming reaction that reacts the fuel and water.

[0017] In one embodiment, in the step of determining the specific mode, the control unit may determine the first mode as the specific mode when the component ratio information of the second gas is less than the first threshold ratio information, and determine the second mode as the specific mode when the component ratio information of the second gas is greater than or equal to the first threshold ratio information.

[0018] In one embodiment, the step of determining the specific flow path may include: the control unit obtaining estimated component ratio information of the first gas based on (i) flow rate information of the fuel, (ii) flow rate information of a third gas supplied to at least a portion of the fuel cell stack and the reformer, and (iii) flow rate information of a recirculated gas supplied from the fuel cell stack to the reformer; and the control unit determining the specific flow path based on the estimated component ratio information of the first gas.

[0019] In one embodiment, the step of determining the specific flow path may include: the control unit obtaining information on the ratio of a measured component of the first gas flowing through a third flow path connecting the reformer and the valve; and the control unit determining the specific flow path based on the information on the ratio of the measured component of the first gas.

[0020] In one embodiment, the component ratio information of the first gas may be any one of (i) ratio information of water vapor and methane and ratio information of oxygen and methane.

[0021] In one embodiment, in the step of determining the specific flow path, the control unit may determine the first flow path as the specific flow path when the component ratio information of the first gas is less than the second threshold ratio information, and determine the second flow path as the specific flow path when the component ratio information of the first gas is greater than or equal to the second threshold ratio information.

[0022] A fuel cell system according to one embodiment disclosed in this document may include: a reformer that generates a first gas using a first reaction with respect to fuel; a fuel cell stack that produces electrical energy based on said fuel; a valve that switches the flow direction of said first gas so that said first gas flows into either a first flow path bypassing said fuel cell stack or a second flow path connected to said fuel cell stack; and a control unit that determines a specific flow path among said first flow path and said second flow path based on information regarding the component ratio of said first gas, and controls said valve to cause said first gas to flow through said specific flow path.

[0023] In one embodiment, when the valve is controlled to allow the first gas to flow through the second flow path, the control unit may determine a specific mode among a first mode in which the supply of the third gas to the reformer is maintained and a second mode in which the supply of the third gas to the reformer is cut off, based on information regarding the component ratio of the second gas generated from the reformer.

[0024] In one embodiment, when the second mode is determined to be the specific mode, the reformer generates a fourth gas using the second reaction with the fuel, and the fuel cell stack can produce electrical energy using the third gas and the fourth gas.

[0025] In one embodiment, the control unit may obtain information on the estimated component ratio of the first gas based on (i) flow rate information of the fuel, (ii) flow rate information of a third gas supplied to at least a part of the fuel cell stack and the reformer, and (iii) flow rate information of a recirculated gas supplied from the fuel cell stack to the reformer, and determine the specific flow path based on the information on the estimated component ratio of the first gas.

[0026] In one embodiment, the control unit may obtain information on the ratio of a measured component of the first gas flowing through a third flow path connecting the reformer and the valve, and determine the specific flow path based on the information on the ratio of the measured component of the first gas.

[0027] In one embodiment, the control unit may determine the first flow path as the specific flow path when the component ratio information of the first gas is less than the second threshold ratio information, and determine the second flow path as the specific flow path when the component ratio information of the first gas is greater than or equal to the second threshold ratio information. Effects of the invention

[0028] According to the present disclosure, a method and system for preventing carbon deposition at the fuel electrode of a fuel cell stack can be provided.

[0029] According to the present disclosure, a method and system for increasing the lifespan of a fuel cell stack can be provided.

[0030] In addition, various effects identified directly or indirectly through this document may be provided. Brief explanation of the drawing

[0031] FIG. 1 is a flowchart illustrating a method according to one embodiment of the present disclosure. FIG. 2 is a flowchart illustrating a method according to one embodiment of the present disclosure. FIG. 3 is a flowchart illustrating a method according to one embodiment of the present disclosure. FIG. 4 is a drawing illustrating a system according to one embodiment of the present disclosure. In relation to the description of the drawings, the same or similar reference numerals may be used for identical or similar components. Specific details for implementing the invention

[0032] Some embodiments of the present invention are described in detail below with reference to exemplary drawings. It should be noted that in assigning reference numerals to the components of each drawing, the same components are given the same reference numeral whenever possible, even if they are shown in different drawings. Furthermore, in describing embodiments of the present invention, detailed descriptions of related known components or functions are omitted if it is determined that such detailed descriptions would hinder understanding of the embodiments of the present invention. In particular, various embodiments of this document are described with reference to the accompanying drawings. However, this is not intended to limit the technology described in this document to specific embodiments, and it should be understood that it includes various modifications, equivalents, and / or alternatives to the embodiments of this document. In relation to the description of the drawings, similar reference numerals may be used for similar components.

[0033] In describing the components of the embodiments of the present invention, terms such as first, second, A, B, (a), (b), etc., may be used. These terms are used merely to distinguish the components from other components and do not limit the essence, order, or sequence of the components. Furthermore, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which the present invention pertains. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in this application. For example, expressions such as “first,” “second,” “first,” or “second” used in this document may modify various components regardless of order and / or importance, and are used merely to distinguish one component from another and do not limit the components. For example, the first user device and the second user device may represent different user devices regardless of order or importance. For example, without departing from the scope of rights set forth in this document, the first component may be named the second component, and similarly, the second component may be renamed the first component.

[0034] In this document, expressions such as “have,” “may have,” “include,” or “may include” refer to the existence of the relevant feature (e.g., numerical values, functions, actions, or components, etc.) and do not exclude the existence of additional features.

[0035] Where it is stated that a certain component (e.g., a first component) is “(operatively or communicatively) coupled with / to” or “connected to” another component (e.g., a second component), it should be understood that the said certain component may be directly connected to the said other component or connected through another component (e.g., a third component). On the other hand, where it is stated that a certain component (e.g., a first component) is “directly connected” or “directly connected” to another component (e.g., a second component), it may be understood that no other component (e.g., a third component) exists between the said certain component and the said other component.

[0036] The expression “configured to” as used in this document may be replaced with, depending on the context, for example, “suitable for,” “having the capacity to,” “designed to,” “adapted to,” “made to,” or “capable of.”

[0037] The term “configured (or set to)” may not necessarily mean only that which is “specifically designed to” in hardware. Instead, in some cases, the expression “device configured to” may mean that the device is “capable of” doing so in conjunction with other devices or components. For example, the phrase “processor configured (or set to) perform A, B, and C” may mean a dedicated processor for performing the said operations (e.g., an embedded processor), or a generic-purpose processor (e.g., a CPU or an application processor) capable of performing said operations by executing one or more software programs stored in a memory device. The terms used herein are used merely to describe specific embodiments and are not intended to limit the scope of other embodiments. A singular expression may include a plural expression unless the context clearly indicates otherwise. Terms used herein, including technical or scientific terms, may have the same meaning as generally understood by a person of ordinary skill in the art described herein. Terms used in this document that are defined in general dictionaries may be interpreted as having the same or similar meaning as they have in the context of the relevant technology, and are not to be interpreted in an ideal or overly formal sense unless explicitly defined in this document. In some cases, even terms defined in this document shall not be interpreted to exclude the embodiments of this document.

[0038] In this document, expressions such as “A or B,” “at least one of A or / and B,” or “one or more of A or / and B” may include all possible combinations of the items listed together. For example, “A or B,” “at least one of A and B,” or “at least one of A or B” may refer to cases including (1) at least one A, (2) at least one B, or (3) both at least one A and at least one B. Additionally, in describing the components of an embodiment of the present invention, 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,” “at least one of A, B, or C,” and “at least one of A, B, C, or any combination thereof” may each include any one of the items listed together with the corresponding phrase, or all possible combinations thereof. In particular, phrases such as “A, B, C, or at least one of any combination thereof” may include A, B, or C, or combinations thereof such as AB or ABC, etc.

[0039] Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 1 to 4.

[0040] FIG. 1 is a flowchart illustrating a method according to one embodiment of the present disclosure.

[0041] First, the reformer can generate a first gas using a first reaction with the fuel (S110).

[0042] At this time, the first reaction may be a partial oxidation reaction in which fuel (e.g., methane) and air (e.g., oxygen) react. Additionally, the first gas may include water (H2O) and carbon (C), etc.

[0043] And, when a first gas is generated by a reformer according to step S110, the control unit can determine a specific flow path through which the first gas flows, among a first flow path bypassing the fuel cell stack and a second flow path connected to the fuel cell stack, based on the component ratio information of the first gas (S120).

[0044] At this time, the component ratio information of the first gas may be either (i) water vapor and methane ratio information (S / C ratio) and (ii) oxygen and methane ratio information (O / C ratio).

[0045] That is, the control unit determines whether there is a high risk of carbon deposition on the fuel electrode of the fuel cell stack based on the component ratio information of the first gas, and if there is a high risk of carbon deposition on the fuel electrode, the first gas is not introduced into the fuel cell stack but bypasses the fuel cell stack, and if there is a low risk of carbon deposition on the fuel electrode, the first gas is supplied to the fuel cell stack.

[0046] For example, the control unit can determine a first flow path that bypasses the fuel cell stack as a specific flow path when the component ratio information of the first gas is less than the second threshold ratio information.

[0047] As another example, the control unit can determine a second flow path connected to a fuel cell stack as a specific flow path when the component ratio information of the first gas is greater than or equal to the second threshold ratio information.

[0048] In addition, the component ratio information of the first gas may be a value directly measured through a sensor, but is not limited thereto.

[0049] For example, the control unit may obtain information on the estimated component ratio of a first gas based on (i) flow rate information of fuel (e.g., methane) supplied to the reformer, (ii) flow rate information of a third gas (e.g., air (or oxygen)) supplied to at least some of the fuel cell stack and the reformer, and (iii) flow rate information of a recirculated gas that is recirculated to the reformer among the gases reacted at the fuel electrode of the fuel cell stack. For reference, the recirculated gas may be recirculated to the reformer through an ejector. Furthermore, the control unit may determine a specific flow path through which the first gas flows based on the information on the estimated component ratio of the first gas.

[0050] As another example, the control unit can obtain information on the ratio of the measured component of the first gas flowing through a third flow path connecting the reformer and the valve. For instance, the control unit can obtain information on the ratio of the measured component of the first gas measured through a sensor installed in the third flow path. Then, the control unit can determine a specific flow path based on the information on the ratio of the measured component of the first gas.

[0051] And, when a specific path is determined according to step S120, the control unit can control the valve to cause the first gas to flow through the specific path (S130).

[0052] For example, the valve may be a three-way valve, the input port of the valve may be connected to a reformer through a third path, the first output port of the valve may be connected to a first path bypassing a fuel cell stack, and the second output port of the valve may be connected to a second path connected to a fuel cell stack.

[0053] For example, if the component ratio information of the first gas is less than the second threshold ratio information, the control unit can control the valve to open the first output port and close the second output port. By doing so, the control unit can cause the first gas to flow through the first flow path.

[0054] As another example, if the component ratio information of the first gas is greater than or equal to the second threshold ratio information, the control unit can control the valve to close the first output port and open the second output port. By doing so, the control unit can cause the first gas to flow through the second flow path.

[0055] Meanwhile, when the valve is controlled so that the first gas flows through the second path, the first gas can be supplied to the anode of the fuel cell stack, and at this time, a portion of the gas reacted at the anode can be recirculated to the reformer via an ejector (recirculated gas). Additionally, the gas remaining without reacting at the anode can be supplied to a burner (post-combustion unit) and combusted by the burner to generate thermal energy. At this time, the thermal energy can be supplied to the reformer.

[0056] And, based on the component ratio information of the second gas generated from the reformer, the control unit can determine a specific mode among (i) a first mode in which the supply of a third gas (e.g., air (or oxygen)) to the reformer is maintained and (ii) a second mode in which the supply of the third gas to the reformer is cut off.

[0057] In this case, the second gas may be a gas produced using a first reaction with respect to fuel. Additionally, the first reaction may be a partial oxidation reaction in which fuel (e.g., methane) and air (e.g., oxygen) react. Additionally, the second gas may include water (H2O) and carbon (C), etc. For reference, the first gas and the second gas may be the same gas.

[0058] For example, if the component ratio information of the second gas is less than the first threshold ratio information, the control unit can determine the first mode in which the supply of the third gas to the reformer is maintained as a specific mode.

[0059] As another example, if the component ratio information of the second gas is greater than or equal to the first threshold ratio information, the control unit can determine a second mode in which the supply of the third gas to the reformer is cut off as a specific mode.

[0060] In addition, if a second mode in which the supply of a third gas to the reformer is cut off is determined to be a specific mode, the reformer can generate a fourth gas using a second reaction with the fuel.

[0061] In addition, the fuel cell stack can produce electrical energy using the third gas and the fourth gas.

[0062] For example, the second reaction may be a reforming reaction in which fuel (e.g., methane) and water are reacted. Additionally, the third gas may be air (e.g., oxygen) supplied to the air electrode of the fuel cell stack. Furthermore, the fourth gas may include hydrogen and carbon monoxide, etc., as a gas generated by the reforming reaction.

[0063] FIG. 2 is a flowchart illustrating a method according to one embodiment of the present disclosure, illustrating a process in which a control unit controls a valve to control the flow path of a first gas.

[0064] Referring to FIG. 2, fuel and air can be supplied to the reformer (S210).

[0065] And, when fuel and air react by partial oxidation to produce a first gas, information on the component ratio of the first gas can be obtained (S220).

[0066] And, the control unit can compare the component ratio information of the first gas with the second threshold ratio information (S230).

[0067] If the component ratio information of the first gas is less than the second threshold ratio information, the control unit controls the valve so that the first gas flows through the first flow path, and accordingly, the first gas bypassing the fuel cell stack can be supplied to the ejector (S240).

[0068] If the component ratio information of the first gas is greater than or equal to the second threshold ratio information, the control unit controls the valve so that the first gas flows through the second flow path, and accordingly, the first gas can be supplied to the fuel cell stack (S250).

[0069] FIG. 3 is a flowchart illustrating a method according to one embodiment of the present disclosure, illustrating the process of completing the startup of a fuel cell stack by blocking oxygen supplied to a reformer based on ratio information of gas supplied to the fuel cell stack.

[0070] Referring to FIG. 3, the control unit can control the valve so that the second gas flows through the second flow path, thereby supplying the second gas to the fuel cell stack (S310).

[0071] And, some of the second gas reacted in the fuel cell stack can be supplied to the burner, and the rest can be supplied to the ejector (S320).

[0072] And, the control unit can compare the component ratio information of the second gas with the first threshold ratio information (S330).

[0073] If the component ratio information of the second gas is less than the first threshold ratio information, steps S310, S320, and S330 may be repeated.

[0074] If the component ratio information of the first gas is greater than or equal to the second critical ratio information, the control unit may block the supply of the third gas (e.g., air) to the reformer (S340).

[0075] Then, a third gas (e.g., air) may be supplied to the air electrode of the fuel cell stack, and a fourth gas may be supplied to the fuel electrode (S350). At this time, the fourth gas may be a gas (e.g., hydrogen, carbon monoxide, etc.) produced by reacting fuel (e.g., methane) and water in a reformer with the air supply cut off.

[0076] And, the fuel cell stack can produce electrical energy through electrochemical reactions with the third gas and the fourth gas (S360).

[0077] FIG. 4 is a drawing illustrating a fuel cell system according to one embodiment of the present disclosure.

[0078] Referring to FIG. 4, a fuel cell system (1000) according to one embodiment of the present disclosure may include a reformer (401), a fuel cell stack (402), a valve (403), and a control unit (not shown). Additionally, a fuel cell system according to one embodiment of the present disclosure may further include a burner (404) and an ejector (405).

[0079] For example, the reformer (401) can generate a first gas using a first reaction with the fuel.

[0080] Additionally, the fuel cell stack (402) can produce electrical energy based on fuel (e.g., a fourth gas) supplied from the reformer (401).

[0081] Additionally, the valve (403) can switch the flow direction of the first gas so that the first gas flows into either the first flow path (406) that bypasses the fuel cell stack (402) or the second flow path (407) that connects to the fuel cell stack.

[0082] Additionally, the control unit can determine a specific path among the first path (406) and the second path (407) based on the component ratio information of the first gas.

[0083] For example, the control unit may obtain information on the estimated component ratio of a first gas based on (i) information on the flow rate of fuel, (ii) information on the flow rate of a third gas supplied to at least some of the fuel cell stack (402) and the reformer (401), and (iii) information on the flow rate of a recirculated gas supplied from the fuel cell stack (402) through the ejector (405) to the reformer (401) through the recirculation path (408), and determine a specific path based on the information on the estimated component ratio of the first gas. For example, the control unit may (i) obtain fuel flow rate information using a first sensor (S1), (ii) obtain flow rate information of a third gas supplied to at least a part of the fuel cell stack (402) and the reformer (401) using a second sensor (S2), (iii) obtain flow rate information of a recirculated gas supplied from the fuel cell stack (402) through the ejector (405) to the reformer (401) through the recirculation path (408) using a third sensor (S3), and obtain estimated component ratio information of the first gas based on the flow rate information.

[0084] As another example, the control unit may obtain information on the ratio of the measured component of the first gas flowing through the third flow path (409) connecting the reformer (401) and the valve (403), and determine a specific flow path based on the information on the ratio of the measured component of the first gas. For instance, the control unit may obtain information on the ratio of the measured component of the first gas using a fourth sensor (S4) on the third flow path (409).

[0085] For example, the control unit may determine the first flow path (406) as a specific flow path when the component ratio information of the first gas is less than the second threshold ratio information, and determine the second flow path (407) as a specific flow path when the component ratio information of the first gas is greater than or equal to the second threshold ratio information.

[0086] At this time, when the valve is controlled so that the first gas flows through the second path (407), the control unit can determine a specific mode among a first mode in which the supply of the third gas to the reformer (401) is maintained and a second mode in which the supply of the third gas to the reformer (401) is cut off, based on the component ratio information of the second gas generated from the reformer (401).

[0087] At this time, when the second mode is determined to be a specific mode, the reformer (401) generates a fourth gas using the second reaction with the fuel, and the fuel cell stack (402) can produce electrical energy using the third gas and the fourth gas.

[0088] The fuel cell system (1000) described above can be applied to a ship.

[0089] The above description is merely an illustrative explanation of the technical concept of the present invention, and those skilled in the art to which the present invention pertains will be able to make various modifications and variations within the scope of the essential characteristics of the present invention.

[0090] The embodiments described above may be implemented as hardware components, software components, and / or combinations of hardware and software components. For example, the devices, methods, and components described in the embodiments may be implemented using a general-purpose computer or a special-purpose computer, such as, for example, a processor, a controller, an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable gate array (FPGA), a programmable logic unit (PLU), a microprocessor, or any other device capable of executing and responding to instructions. The processing unit may execute an operating system (OS) and software applications executed on said operating system. Additionally, the processing unit may access, store, manipulate, process, and generate data in response to the execution of the software. For ease of understanding, the processing unit may be described as being used as a single unit, but those skilled in the art will understand that the processing unit may include multiple processing elements and / or multiple types of processing elements. For example, the processing unit may include multiple processors or one processor and one controller. In addition, other processing configurations, such as parallel processors, are also possible.

[0091] Software may include computer programs, code, instructions, or a combination of one or more of these, and may configure a processing unit to operate as desired or command the processing unit independently or collectively. Software and / or data may be permanently or temporarily embodied in any type of machine, component, physical device, virtual equipment, computer storage medium or device, or transmitted signal wave in order to be interpreted by the processing unit or to provide instructions or data to the processing unit. Software may be distributed over networked computer systems and may be stored or executed in a distributed manner. Software and data may be stored on computer-readable recording media.

[0092] The method according to the embodiment may be implemented in the form of program instructions that can be executed through various computer means and recorded on a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, etc., either alone or in combination, and the program instructions recorded on the medium may be those specifically designed and configured for the embodiment or those known and available to those skilled in the art of computer software. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks, and magnetic tapes; optical recording media such as CD-ROMs and DVDs; magneto-optical media such as floptical disks; and hardware devices specifically configured to store and execute program instructions, such as ROM, RAM, and flash memory. Examples of program instructions include machine code, such as that generated by a compiler, as well as high-level language code that can be executed by a computer using an interpreter, etc.

[0093] The hardware device described above may be configured to operate as one or more software modules to perform the operation of the embodiment, and vice versa.

[0094] Although the embodiments have been described above with reference to the limited drawings, those skilled in the art can apply various technical modifications and variations based thereon. For example, appropriate results may be achieved even if the described techniques are performed in a different order than described, and / or if the components of the described system, structure, device, circuit, etc. are combined or assembled in a form different from described, or replaced or substituted by other components or equivalents.

[0095] Therefore, other implementations, other embodiments, and equivalents to the claims also fall within the scope of the claims set forth below.

[0096] Accordingly, the embodiments disclosed in this invention are intended to illustrate, not limit, the technical concept of the invention, and the scope of the technical concept of the invention is not limited by these embodiments. The scope of protection of this invention shall be interpreted by the claims below, and all technical concepts within an equivalent scope shall be interpreted as being included within the scope of rights of this invention.

Claims

Claim 1 A method for controlling a fuel cell system, comprising: a step of generating a first gas using a first reaction with fuel by a reformer; a step of a control unit determining, based on component ratio information of the first gas, a specific flow path in which the first gas flows among a first flow path bypassing a fuel cell stack and a second flow path connected to the fuel cell stack; and a step of the control unit controlling a valve to cause the first gas to flow through the specific flow path, wherein in the step of controlling the valve, the control unit controls the valve to cause the first gas to flow through the second flow path, and after the step of controlling the valve, the control unit further comprises a step of determining a specific mode among a first mode in which the supply of a third gas to the reformer is maintained and a second mode in which the supply of the third gas to the reformer is cut off, based on component ratio information of the second gas generated from the reformer. Claim 2 delete Claim 3 A method for controlling a fuel cell system according to claim 1, further comprising: a step of determining a specific mode, wherein the control unit determines the second mode as the specific mode; and, after the step of determining the specific mode, a step of the reformer generating a fourth gas using a second reaction with the fuel; and a step of the fuel cell stack producing electrical energy using the third gas and the fourth gas. Claim 4 A method for controlling a fuel cell system according to claim 3, wherein the first reaction is a partial oxidation reaction that reacts the fuel and air, and the second reaction is a reforming reaction that reacts the fuel and water. Claim 5 A method for controlling a fuel cell system according to claim 1, wherein, in the step of determining the specific mode, the control unit determines the first mode as the specific mode when the component ratio information of the second gas is less than the first threshold ratio information, and determines the second mode as the specific mode when the component ratio information of the second gas is greater than or equal to the first threshold ratio information. Claim 6 A method for controlling a fuel cell system according to claim 1, wherein the step of determining the specific flow path comprises: a step in which the control unit obtains estimated component ratio information of the first gas based on (i) flow rate information of the fuel, (ii) flow rate information of a third gas supplied to at least a part of the fuel cell stack and the reformer, and (iii) flow rate information of a recirculated gas supplied from the fuel cell stack to the reformer; and a step in which the control unit determines the specific flow path based on the estimated component ratio information of the first gas. Claim 7 A method for controlling a fuel cell system according to claim 1, wherein the step of determining the specific flow path comprises: the step of the control unit obtaining information on the ratio of a measured component of the first gas flowing through a third flow path connecting the reformer and the valve; and the step of the control unit determining the specific flow path based on the information on the ratio of the measured component of the first gas. Claim 8 A method for controlling a fuel cell system according to claim 1, wherein the component ratio information of the first gas is one of (i) ratio information of water vapor and methane and ratio information of oxygen and methane. Claim 9 A method for controlling a fuel cell system according to claim 1, wherein, in the step of determining the specific flow path, the control unit determines the first flow path as the specific flow path when the component ratio information of the first gas is less than the second threshold ratio information, and determines the second flow path as the specific flow path when the component ratio information of the first gas is greater than or equal to the second threshold ratio information. Claim 10 A fuel cell system comprising: a reformer that generates a first gas using a first reaction with respect to fuel; a fuel cell stack that produces electrical energy based on said fuel; a valve that switches the flow direction of said first gas so that said first gas flows into either a first flow path bypassing said fuel cell stack or a second flow path connected to said fuel cell stack; and a control unit that determines a specific flow path among said first flow path and said second flow path based on information regarding the component ratio of said first gas, and controls said valve to cause said first gas to flow through said specific flow path, wherein when said valve is controlled to cause said first gas to flow through said second flow path, said control unit determines a specific mode among a first mode in which the supply of said third gas to said reformer is maintained and a second mode in which the supply of said third gas to said reformer is cut off, based on information regarding the component ratio of said second gas generated from said reformer. Claim 11 delete Claim 12 A fuel cell system according to claim 10, wherein if the second mode is determined to be the specific mode, the reformer generates a fourth gas using a second reaction with the fuel, and the fuel cell stack produces electrical energy using the third gas and the fourth gas. Claim 13 A fuel cell system according to claim 10, wherein the control unit obtains estimated component ratio information of the first gas based on (i) flow rate information of the fuel, (ii) flow rate information of a third gas supplied to at least a part of the fuel cell stack and the reformer, and (iii) flow rate information of a recirculated gas supplied from the fuel cell stack to the reformer, and determines the specific flow path based on the estimated component ratio information of the first gas. Claim 14 A fuel cell system according to claim 10, wherein the control unit obtains information on the ratio of a measured component of the first gas flowing through a third path connecting the reformer and the valve, and determines the specific path based on the information on the ratio of the measured component of the first gas. Claim 15 A fuel cell system according to claim 10, wherein the control unit determines the first flow path as the specific flow path when the component ratio information of the first gas is less than the second threshold ratio information, and determines the second flow path as the specific flow path when the component ratio information of the first gas is greater than or equal to the second threshold ratio information.

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