Incorporated air supplying apparatus for fuel cell stack and mehtod for controlling air flow for fuel cell stack using the same

Abstract

An air supply device for an integrated fuel cell stack and a method for controlling air flow using the same are introduced, comprising an air supply unit for supplying air to a plurality of fuel cell stacks, a plurality of pipes configured to deliver air supplied from the air supply unit to each fuel cell stack, a flow meter and a valve installed in each pipe, and a controller capable of controlling the opening amount of the valves based on measured flow information, wherein the opening amount of the valve installed in each pipe is controlled by the controller to enable air flow control for each pipe.

Description

Technology Field

[0001] The present invention relates to an apparatus and method for supplying air to a fuel cell system, and more specifically, to an apparatus for supplying air to a plurality of fuel cell stacks, such as a power generation fuel cell, and an air supply control method using the same. Background Technology

[0003] A fuel cell is an energy conversion device that converts the chemical energy contained in fuel into electrical energy through an electrochemical reaction without converting it into heat through combustion. It can be used not only to supply power for industrial, residential, and automotive use, but also to power small electrical and electronic products and portable devices.

[0004] For example, in a Polymer Electrolyte Membrane Fuel Cell (PEMFC) with high power density, the Membrane-Electrode Assembly (MEA), which is the main component, is located at the innermost part. The MEA consists of a solid polymer electrolyte membrane capable of transporting hydrogen ions, and cathodes and anodes, which are electrode layers coated with catalysts on both sides of the electrolyte membrane to allow hydrogen and oxygen to react.

[0005] A fuel cell includes a fuel cell stack that generates electrical energy through an internal electrochemical reaction, a hydrogen supply system that supplies hydrogen to the fuel cell stack, an air supply system that supplies air containing oxygen to the fuel cell stack, and a cooling system that controls the operating temperature of the fuel cell stack.

[0006] Fuel cells can supply industrial or residential power in buildings or be mounted on vehicles to provide driving power. In particular, to manufacture power generation fuel cells capable of generating large amounts of power by including multiple fuel cell stacks and being installed in buildings, it is required to produce large fuel cell stacks. However, since manufacturing large stacks presents difficulties in achieving stacking of the components and uniform distribution of reactants, a method of connecting multiple fuel cell stacks is generally utilized.

[0007] Meanwhile, when configuring a large-capacity power generation fuel cell system using multiple fuel cell stacks in this manner, there was still a problem in that uniform distribution of air was difficult because the piping paths from the air supply device to individual stacks differed from stack to stack.

[0008] The matters described above as background technology are intended only to enhance understanding of the background of the present invention and should not be construed as an acknowledgment that they constitute prior art already known to those skilled in the art. Prior art literature

[0010] (Patent Document 0001) KR 10-1358335 B The problem to be solved

[0011] The present invention is proposed to solve these problems and aims to provide an air supply device for an integrated fuel cell stack and a method for controlling air flow rate using the same, which enables the amount of air supplied to each fuel cell stack to a desired level without applying an integrated air manifold when using multiple stacks to form a large stack.

[0012] In particular, another objective of the present invention is to improve the operation and maintenance efficiency of fuel cell stacks by configuring them to enable air flow control of individual fuel cell stacks. means of solving the problem

[0014] An air supply device for an integrated fuel cell stack according to the present invention for achieving the above-mentioned purpose comprises: an air supply unit for supplying air to a plurality of fuel cell stacks; a plurality of pipes configured to deliver air supplied from the air supply unit to each fuel cell stack; a plurality of valves installed in each pipe and configured to enable control of the air flow rate flowing through each pipe; a plurality of flow meters for measuring the air flow rate flowing through each pipe; and a controller capable of controlling the opening amount of the valves based on flow rate information measured by the flow meters; wherein the controller is configured to control the opening amount of the valves installed in each pipe so as to enable control of the air flow rate for each pipe.

[0015] The controller is configured to enable initial setting control of the opening amounts of the valves, and during initial setting control, while all valves are open and the air supply unit is operating at a preset calibration rotational speed, the controller controls the opening amount of the valves to extract information on the opening amount of the valves such that the flow rate deviation in each pipe meets within a preset standard, and the controller can store the extracted information on the opening amount of the valves as the initial setting.

[0016] The controller can repeat the process of reducing the flow deviation one or more times by controlling the opening amount of the valve on the maximum flow pipe side to close the opening of the valve on the maximum flow pipe side based on flow information measured by each flow meter during initial setting control, so that the flow of the maximum flow pipe approaches the average flow information, which is the average value of the values ​​measured by each flow meter.

[0017] The controller is configured to control the supply flow rate supplied from the air supply unit, and when equal air flow rate control for all fuel cell stacks is required, the air flow rate supplied through each pipe is measured by each flow meter while the flow rate supplied from the air supply unit is controlled, and the controller controls the opening of the valve on the pipe side where the maximum flow rate flows to the closing direction based on the flow rate information measured by each flow meter so that the flow rate deviation between the flow rate of the maximum flow rate pipe and the average flow rate information, which is the average value of the values ​​measured by each flow meter, is reduced, and the controller can repeat the average flow rate measurement and flow rate deviation reduction control until the flow rate deviation in each pipe meets within a preset standard.

[0018] Based on flow rate information measured by each flow meter, the controller determines whether the required flow rate value for each fuel cell stack has been reached, and if the required flow rate value for each fuel cell stack is not reached even if the flow rate deviation in each pipe meets within a preset standard, the controller may repeatedly perform control of the supply air flow rate of the air supply unit, measurement of the average flow rate, and control of flow rate deviation reduction until the required flow rate value is reached.

[0019] The controller is configured to control the supply flow rate supplied from the air supply unit, and when air flow rate control for a specific fuel cell stack is required, the total flow rate of air supplied to the remaining fuel cell stacks excluding the fuel cell stack for which the flow rate is to be controlled is measured and stored. The controller can control the air flow rate for a specific fuel cell stack by measuring the total flow rate of air supplied to the remaining fuel cell stacks in real time while controlling the opening of the valve for the fuel cell stack for which the flow rate is to be controlled according to the required air flow rate, and by repeating the process of controlling the supply flow rate supplied from the air supply unit one or more times until the total flow rate for the remaining stacks measured in real time reaches the total flow rate for the remaining stacks stored in advance.

[0020] The controller is configured to control the supply flow rate supplied from the air supply unit, and when air flow rate control for two or more specific fuel cell stacks is required, the total flow rate of air supplied to the remaining fuel cell stacks, excluding the two or more fuel cell stacks for which the flow rate is to be controlled, is measured and stored. The controller can control the air flow rate for a specific fuel cell stack by changing the opening of the valves for the fuel cell stack for which the flow rate is to be controlled according to the required air flow rate, measuring the total flow rate of air supplied to the remaining fuel cell stacks in real time, and repeating the process of controlling the supply flow rate supplied from the air supply unit one or more times until the total flow rate for the remaining stacks measured in real time reaches the total flow rate for the remaining stacks stored in advance.

[0021] If the sum of the flow rate changes for each fuel cell stack requiring air flow rate control exceeds a preset reference flow rate, the controller may divide the air flow rate control so that the sum of the flow rate changes for each fuel cell stack is within the preset reference flow rate.

[0022] In addition, the air flow rate control method using an air supply device of an integrated fuel cell stack according to the present invention includes an initial setting control process for the opening amount of valves by a controller before the operation of the fuel cell stack, and in the initial setting control process, while all valves are open and the air supply unit is operating at a preset calibration rotational speed, the opening amount of the valves is controlled by the controller to extract information on the opening amount of the valves such that the flow rate deviation in each pipe meets within a preset standard, and the controller can store the extracted information on the opening amount of the valves as an initial setting.

[0023] The initial setting control process may include: an initiation step in which all valves are opened and the air supply unit operates at a preset calibration rotational speed; an average flow rate calculation step in which average flow rate information is calculated based on flow rate information measured by each flow meter; a valve opening control step in which the opening of the valve on the pipe side where the maximum flow rate flows is adjusted in the closing direction; a flow rate deviation verification step in which the maximum flow rate deviation determined from the difference between the flow rate value of the maximum flow rate pipe reduced according to the valve opening control step and the average flow rate information is checked to see if it is within a preset standard; and a step of extracting the opening amount information of each valve and storing it as an initial setting when the maximum flow rate deviation is within a preset standard.

[0024] In the flow rate deviation check step, if the maximum flow rate deviation deviates from a preset standard, the average flow rate calculation step, the valve opening control step, and the flow rate deviation check step may be repeated until the maximum flow rate deviation reaches within the preset standard.

[0025] In addition, an air flow rate control method using an air supply device of an integrated fuel cell stack according to an embodiment of the present invention may include: a supply flow rate control step for controlling the flow rate supplied from an air supply unit when a demand for equal air flow rate control for all fuel cell stacks occurs during the operation of the fuel cell stack; an average flow rate calculation step for calculating average flow rate information by measuring the air flow rate supplied through each pipe by each flow meter; a valve opening control step for controlling the opening of a valve on the pipe side where the maximum flow rate flows in a closing direction; a flow rate deviation verification step for confirming whether the maximum flow rate deviation determined from the difference between the flow rate value of the maximum flow rate pipe reduced according to the valve opening control step and the average flow rate information is within a preset standard; and a demand flow rate attainment verification step for determining whether the required flow rate value for each fuel cell stack has been reached based on the flow rate information measured by each flow meter.

[0026] If it is confirmed through the flow rate deviation verification step that the maximum flow rate deviation deviates from a preset standard, the average flow rate calculation step, the valve opening control step, and the flow rate deviation verification step are repeated until the maximum flow rate deviation reaches within the preset standard. If it is confirmed through the required flow rate attainment verification step that the required flow rate value for each fuel cell stack is not reached, the air supply flow rate from the air supply unit is readjusted according to the required flow rate value, and the steps below the average flow rate calculation step can be repeated.

[0027] A method for controlling air flow using an air supply device of an integrated fuel cell stack according to an embodiment of the present invention may include: a total flow detection step of measuring and storing the total flow of air supplied to the remaining fuel cell stacks excluding the fuel cell stack for which the flow is to be controlled when a request for air flow control for a specific fuel cell stack occurs during the operation of the fuel cell stack; a valve opening control step of controlling the opening of a valve for the fuel cell stack for which the flow is to be controlled according to the required air flow; and a supply flow control step of measuring the total flow of air supplied to the remaining fuel cell stacks in real time and controlling the supply flow supplied from the air supply unit until the total flow for the remaining stacks measured in real time reaches the total flow for the remaining stacks stored in advance.

[0028] Additionally, when a request for air flow control for two or more specific fuel cell stacks occurs during the operation of a fuel cell stack, the method may include: a total flow detection step for measuring and storing the total flow of air supplied to the remaining fuel cell stacks excluding the two or more fuel cell stacks for which the flow is to be controlled; a valve opening control step for adjusting the opening of the valve for the two or more fuel cell stacks for which the flow is to be controlled according to the required air flow; and a supply flow control step for measuring the total flow of air supplied to the remaining fuel cell stacks in real time and adjusting the supply flow supplied from the air supply unit until the total flow for the remaining stacks measured in real time reaches the total flow for the remaining stacks stored in advance. Effects of the invention

[0030] According to the air supply device and air supply control method of the integrated fuel cell stack of the present invention, by configuring the air supply device to enable flow rate control for each individual stack of air supplied to each stack, the problem of air distribution that may occur due to air piping paths separated by stack is resolved, thereby providing the effect of enabling uniform air supply amount control for each stack.

[0031] In addition, according to the present invention, since flow rate control is possible for each individual air stack, individual stacks can be replaced even during the operation of the fuel cell system, and there is an advantage in that a separate air supply logic can be applied to each stack based on status information such as stack durability or power generation amount.

[0032] In addition, since independent flow rate control is possible for each fuel cell stack, stack durability is improved and the desired level of power generation can be continuously maintained, thereby improving the operation and maintenance efficiency of the fuel cell system. Brief explanation of the drawing

[0034] FIG. 1 is a schematic diagram showing the schematic configuration of an air supply device of an integrated fuel cell stack according to an embodiment of the present invention. FIG. 2 is a flowchart illustrating a method for controlling air flow using an air supply device of an integrated fuel cell stack according to an embodiment of the present invention. FIG. 3 is a flowchart illustrating an example of performing an initial setting of a valve in an air flow control method according to an embodiment of the present invention. FIG. 4 is a flowchart illustrating an example of performing total air flow control in an air flow control method according to an embodiment of the present invention. FIG. 5 is a flowchart illustrating an example of controlling the air flow of a specific individual stack in an air flow control method according to an embodiment of the present invention. FIG. 6 is a flowchart illustrating an example of controlling the air flow of multiple stacks simultaneously in an air flow control method according to an embodiment of the present invention. FIGS. 7a to 7c illustrate examples of simultaneous air flow control in 10 fuel cell stacks, where FIG. 7a is an example where air flow control of multiple stacks can be performed simultaneously based on the absolute value of the total flow rate change, FIG. 7b is an example where air flow control of multiple stacks cannot be performed simultaneously based on the absolute value of the total flow rate change, and FIG. 7c illustrates an example where air flow control is divided and performed by section when flow control similar to FIG. 7b is required. Specific details for implementing the invention

[0035] The air supply device according to the present invention can be applied to large stacks for relatively large power production, such as power generation fuel cells, and is particularly suitable for cases where multiple fuel cell stacks are configured within a fuel cell system for the purpose of constructing such large stacks. Furthermore, the air supply device according to the present invention is configured to enable integrated control of the air supply volume for individual flow paths connecting multiple stacks from an air blower or air compressor, without using a single air manifold when supplying air to each stack. In particular, the air supply device according to the present invention reduces the variation in the amount of air supplied to each fuel cell stack through these individual flow paths and provides an air supply device capable of individual flow rate control for each stack as needed.

[0036] In this regard, a fuel cell stack in a preferred embodiment of the present invention refers to a single power generation unit in which power is generated by a fuel cell, configured to receive air through an independent flow path connected to an air supply unit (10). For example, such a fuel cell stack may include a plurality of unit cells, and each fuel cell stack may be connected to an air supply flow path assigned to it. However, the fuel cell stack in the present invention is used only to refer to each power generation unit in which flow rate control is performed, and does not necessarily mean only a stack form in which unit cells are stacked. Therefore, even a single cell can be interpreted as being included in the fuel cell stack in the present invention if it is a configuration capable of generating power that is connected by an individual flow path.

[0037] In addition, the number of fuel cell stacks can be appropriately selected according to the required power generation capacity, and if necessary, the air supply device according to the present invention may be applied only to a part of the system. In this case, fuel cell stacks to which air is supplied collectively by an integrated manifold may be included.

[0038] Hereinafter, an air supply device for an integrated fuel cell stack and a method for controlling air flow rate using the same according to various embodiments of the present invention will be described in detail with reference to the attached drawings.

[0039] FIG. 1 is a schematic diagram showing the schematic configuration of an air supply device of an integrated fuel cell stack according to an embodiment of the present invention.

[0040] Referring to FIG. 1, an air supply device (1) of an integrated fuel cell stack according to a preferred embodiment of the present invention includes an air supply unit (10) for supplying air to a plurality of fuel cell stacks (51, 52, 53, 54) and a plurality of pipes (11, 12, 13, 14) that function as flow paths for delivering air supplied from the air supply unit (10) to each fuel cell stack (51, 52, 53, 54). The pipes connected from the air supply unit (10) are branched to each fuel cell stack (51, 52, 53, 54), and flow meters (21, 22, 23, 24) and valves (31, 32, 33, 34) may be installed on the branched air pipes (11, 12, 13, 14). A flow meter (21, 22, 23, 24) installed in each pipe (11, 12, 13, 14) is for measuring the air flow rate supplied to each pipe (11, 12, 13, 14), and a valve (31, 32, 33, 34) is for controlling the air flow rate supplied to each fuel cell stack (51, 52, 53, 54) through the valve (31, 32, 33, 34) by controlling the opening amount, and such valve (31, 32, 33, 34) may be configured as a throttle valve.

[0041] A controller (40) for controlling valves (31, 32, 33, 34) and an air supply unit (10) within an air supply device is included. This controller (40) may be configured to receive flow rate information detected by flow meters (21, 22, 23, 24), and preferably may be configured to control the flow rate of the supplied air based on the detected flow rate information.

[0042] Regarding air flow rate control, the controller (40) can control the opening amount of valves (31, 32, 33, 34) installed in each pipe (11, 12, 13, 14), and air flow rate control for each pipe (11, 12, 13, 14) is possible by controlling the opening amount of these valves (31, 32, 33, 34). Additionally, the controller (40) can control the air supply unit (10), and the air supply unit (10) may be an air blower or air compressor driven by a motor that sucks in outside air and supplies air to the fuel cell stack (51, 52, 53, 54) through the pipes (11, 12, 13, 14). Accordingly, the controller (40) can control the air supply flow rate by controlling the motor rotation speed of the air supply unit (10).

[0043] Specifically, as shown in FIG. 1, a flow meter (21, 22, 23, 24) and a valve (31, 32, 33, 34) assigned to each stack are installed in the pipes (11, 12, 13, 14) connected to each fuel cell stack (51, 52, 53, 54), and preferably, the air flow can be controlled by the controller (40) controlling the rotational speed of the air supply unit (10) and / or the opening amount of the valve based on flow information measured by each flow meter (21, 22, 23, 24).

[0044] In relation to such air flow control, the controller may include a correction function to resolve initial flow rate differences caused by pressure loss, etc., which may occur because the piping paths to each stack are different.

[0045] To this end, the controller is configured to enable initial setting control of the valve opening amounts, and during initial setting control, while all valves are open and the air supply unit is operating at a preset calibration rotational speed, the controller controls the valve opening amount to extract valve opening amount information such that the flow rate deviation in each pipe meets within a preset standard, and the controller can store the extracted valve opening amount information as the initial setting.

[0046] More specifically, the controller can extract an initial setting value for the valve opening at which the air flow to each pipe becomes relatively constant by repeating the process of reducing the flow deviation while controlling the opening amount of the valve on the maximum flow pipe side to close the opening of the valve on the maximum flow pipe side in accordance with flow information measured by each flow meter during initial setting control, so that the flow of the maximum flow pipe approaches the average flow information, which is the average value of the values ​​measured by each flow meter, one or more times.

[0047] The initial set value for the valve opening extracted in this manner can be stored in a storage element, such as memory within the controller, and through this calibration function, flow rate deviations caused by pressure loss resulting from different piping paths for each fuel cell stack can be reduced. Therefore, if this calibration function is performed before the operation of the fuel cell stacks, a uniform air flow rate can be provided for each stack.

[0048] In addition, the controller can control the total air flow rate evenly for each stack, and can be configured to control the air flow rate for individual stacks or multiple stacks as needed.

[0049] In this regard, a specific method for controlling the air supply flow rate by a controller is explained in more detail with reference to the attached Figures 2 to 6.

[0050] First, FIG. 2 illustrates an air flow rate control method using an air supply device of an integrated fuel cell stack according to an embodiment of the present invention, and FIG. 3 illustrates an example of performing initial setting control (correction function) of a valve.

[0051] Referring to FIG. 2, during fuel cell operation (S202), it is checked whether air flow rate control is required (S203), and if air flow rate control is required, air flow rate control can be performed by the controller (S204). In this regard, an initial setting control step (S201) for the opening amount of the valve may optionally be performed. As previously explained, through this initial setting control step (S201), the flow rate deviation can be reduced in advance before fuel cell operation, thereby enabling uniform air supply to each fuel cell stack.

[0052] Meanwhile, specific steps related to the initial setting control of the valve opening amount are illustrated in Fig. 3.

[0053] When controlling the initial setting of the valve opening amount related to the calibration function, all valves are fully opened by the controller (S301), and the air supply unit is controlled to operate at a preset calibration rotational speed (S302). This calibration rotational speed is a preset value for the initial setting control, and is designated to uniformly set an initial value while the air supply unit is operating at a specific rotational speed.

[0054] Subsequently, the flow meter measures the air flow rate supplied to each fuel cell stack in real time (S303), and detects the valve where the maximum flow rate is flowing based on the measurement results.

[0055] The valve on the flow meter side where the maximum flow rate is confirmed to be flowing must be controlled to reduce the flow rate, so as to control the flow rate to approach the average flow rate. Accordingly, the controller adjusts the opening of the valve where the maximum flow rate is flowing in the closing direction (S304), and the controller checks whether the flow rate values ​​detected in real time from each flow meter meet within a reference range in relation to the measured average flow rate (S305). Here, the average flow rate may be the average value of the flow rate values ​​measured in step S303, or for more accurate measurement, the average value of the flow rate values ​​measured after the valve opening control step of step S304 may be used. Additionally, whether it meets within the reference range in step S305 may be determined by whether the maximum flow rate deviation, which is determined from the difference between the maximum flow rate value and the average flow rate among the measured flow rates, is within a preset reference flow rate.

[0056] Upon verification, if the flow rate deviation in each pipe does not meet the preset criteria (i.e., the maximum flow rate deviation is within the preset flow rate), the process returns to step S303 and repeats the following steps. This process may be repeated until the maximum flow rate deviation reaches the preset criteria.

[0057] On the other hand, if the flow rate deviation in each pipe meets within a preset standard, the initial setting can be completed, so the current opening amount information of each valve is extracted, and the controller can store the extracted opening amount information of the valve as the initial setting (S306).

[0058] FIG. 4 is a flowchart illustrating an example of controlling the total air flow rate in an air flow rate control method according to an embodiment of the present invention.

[0059] In the air flow control method using an air supply device of an integrated fuel cell stack according to one embodiment of the present invention, the method may be implemented when total air flow control is required, that is, when a demand for equal air flow control for all fuel cell stacks occurs during the operation of the fuel cell stack. For example, the case where total air flow control is required may be implemented when there is a demand to control the air flow for all fuel cell stacks equally (a demand for equal increase or decrease in air flow for all stacks) or when the flow rate value at a specific rotational speed of the air supply unit differs from the required flow rate level due to changes in the system operating environment.

[0060] As illustrated in FIG. 4, when a request for total air flow rate control occurs (S401), a step (S402) of measuring the sum of the total supply air flow rates supplied to the fuel cell stack may be performed. The detected total flow rate sum can be used to verify whether a desired flow rate has been reached after a subsequent series of control processes, and in some cases, for example, when a final required flow rate is specified, this step (S402) may be omitted.

[0061] To control the total air flow rate, the rotational speed of the air supply unit can be increased or decreased to control the flow rate to a desired level (S403). In this regard, when controlling the flow rate supplied from the air supply unit, the flow rate can be controlled by immediately changing the required amount of change. However, for more precise control, the rotational speed of the air supply unit can be controlled so that only a minute change in flow rate occurs, which is a preset unit change in flow rate 'q'. After such a minute change in flow rate, precise control can be achieved by repeating a series of control processes to minimize the flow rate deviation between stacks, which will be described later. Such precise control can be more stable in that it prevents a temporary large change in the amount of air supplied to the fuel cell stack.

[0062] After the supply flow rate control step (S403) for controlling the flow rate supplied from the air supply unit, an average flow rate calculation step (S404) is performed to calculate average flow rate information by measuring the air flow rate supplied through each pipe by each flow meter.

[0063] Meanwhile, the controller can perform a valve opening control step (S405) to identify the fuel cell stack with the maximum flow rate from the flow rate information obtained from each flow meter, and to control the flow rate on the pipe side (maximum flow rate) so that it approaches the average flow rate by adjusting the opening of the valve on the pipe side where the maximum flow rate flows in the closing direction. This valve opening control step may be a process of fine-tuning the opening amount of the valve where the maximum flow rate flows until it sufficiently approaches the average flow rate. At this time, whether the opening amount of the maximum flow rate valve has sufficiently approached the average flow rate can be confirmed through a flow rate deviation checking step (S406) which checks whether the maximum flow rate deviation, determined from the difference between the flow rate value of the maximum flow rate pipe reduced according to the valve opening control and the average flow rate, is within a preset standard.

[0064] If, through this flow rate deviation verification step, it is determined that the opening amount of the maximum flow rate valve is sufficiently close to the average flow rate, a required flow rate attainment verification step (S407) is performed to determine whether the required flow rate value for each fuel cell stack has been reached based on the flow rate information measured by each flow meter.

[0065] Meanwhile, if it is confirmed through the flow rate deviation verification step (S406) that the maximum flow rate deviation deviates from a preset standard, the average flow rate calculation step (S404), the valve opening control step (S405), and the flow rate deviation verification step (S406) are repeated until the maximum flow rate deviation reaches within the preset standard.

[0066] Additionally, if it is confirmed through the required flow rate attainment verification step (S407) that the required flow rate value for each fuel cell stack has not been reached, the process returns to step S403 to readjust the air supply flow rate from the air supply unit according to the required flow rate value, and the steps following the average flow rate calculation step (S404) can be repeated.

[0067] Meanwhile, when controlling air flow, there may be cases where air flow control for an individual stack is required due to a problem with that specific individual stack. Figure 5 is a flowchart illustrating an example of performing air flow control when air flow control for a specific individual stack is required in such a case.

[0068] According to FIG. 5, when a request for air flow rate control for a specific fuel cell stack occurs during the operation of the fuel cell stack (S501), a total flow rate detection step (S502) is performed to measure and store the total flow rate of air supplied to the remaining fuel cell stacks excluding the fuel cell stack for which the flow rate is to be controlled.

[0069] Afterwards, a valve opening control step (S503) may be performed to control the opening of a valve for a fuel cell stack to control the flow rate according to the required air flow rate. In this valve opening control step, the required air flow rate control may be performed once as described above, and preferably, the valve opening may be slowly opened to allow a small change in flow rate of unit flow rate change 'q' to occur over a sufficient period of time.

[0070] As explained in the example of Figure 4 above, in order to perform precise control, it is desirable to set the unit flow rate change 'q' to be as small as possible and to repeatedly perform flow rate control.

[0071] When a change in flow rate occurs toward the stack to be controlled through such a valve opening control step (S503), a change in the total flow rate supplied to the remaining stacks occurs depending on the increase or decrease in the air flow rate to that stack. Therefore, to compensate for this change in the total flow rate, control is required to increase or decrease the supply flow rate of the air supply unit. For example, if the flow rate for stack 1 is increased by a unit flow rate change 'q', the total flow rate of the remaining stacks decreases by the same amount as the increase in the flow rate of stack 1; thus, to compensate for this, it is necessary to slowly increase the rotational speed of the air supply unit so that the total flow rate of the remaining stacks increases to the same level as before the flow rate control for stack 1. On the other hand, if flow rate reduction control for stack 1 is required, flow rate reduction control can be achieved by making the unit flow rate change 'q' value negative (-) and controlling the rotational speed of the air supply unit to decrease.

[0072] To this end, as shown in FIG. 5, a supply flow rate control step (S504) may be performed to measure the total flow rate of air supplied to the remaining fuel cell stacks in real time and to adjust the supply flow rate supplied from the air supply unit until the total flow rate for the remaining stacks measured in real time reaches the total flow rate for the remaining stacks stored in advance.

[0073] If the flow rate value for the remaining stack has recovered to the same level as before, the control of the air supply unit is terminated, and a step (S505) of checking whether the air flow rate of the specific stack to be controlled has reached the initially required air flow rate value may be performed.

[0074] Upon verification, if the required air flow rate is reached, the control is terminated, and if it is not reached, the steps S502 and below can be repeated until the required air flow rate value is reached.

[0075] Meanwhile, Figure 6 illustrates an air flow rate control method according to an embodiment of the present invention, and unlike Figure 5, it describes an example of a case where air flow rate control of multiple stacks is performed simultaneously.

[0076] As illustrated in FIG. 6, when a request for air flow rate control for two or more fuel cell stacks occurs during the operation of a fuel cell stack (S601), a total flow rate detection step (S602) may be performed to measure and store the total flow rate of air supplied to the remaining fuel cell stacks, excluding the two or more fuel cell stacks for which the flow rate is to be controlled.

[0077] Afterwards, a valve opening control step (S603) may be performed to control the opening of a valve for two or more fuel cell stacks to control the flow rate according to the required air flow rate, thereby causing a change in flow rate.

[0078] In this valve opening control step (S603), the flow rate change can be slowly adjusted stepwise by a unit flow rate change 'q', as in the example of FIG. 5 above.

[0079] After the valve opening control step (S603) for flow rate change is performed, a supply flow rate control step (S604) may be performed to compensate for the total flow rate change for the remaining stacks by measuring the total flow rate of air supplied to the remaining fuel cell stacks in real time and adjusting the supply flow rate supplied from the air supply unit until the total flow rate for the remaining stacks measured in real time reaches the total flow rate for the remaining stacks stored in advance.

[0080] For example, if the flow rate for stacks 1 through 3 is increased by a unit flow rate change 'q' for each, the total flow rate of the remaining stacks decreases by the same amount as the increase in the flow rate of stacks 1 through 3. To compensate for this, control is performed to increase the total flow rate of the remaining stacks by slowly increasing the rotational speed of the air supply unit. On the other hand, if control to reduce the flow rate for stacks 1 through 3 is required, control to reduce the total flow rate of the remaining stacks can be achieved by making the unit flow rate change 'q' negative (-) and controlling the rotational speed of the air supply unit to decrease.

[0081] Meanwhile, in another embodiment of the present invention, prior to the total flow rate detection step (S602), the method may be configured to further include a step of determining whether the sum of the flow rate changes for each fuel cell stack requiring air flow rate control exceeds a preset reference flow rate. In such an example, if the sum of the flow rate changes for each fuel cell stack requiring air flow rate control, i.e., the total flow rate change (Q), exceeds the reference flow rate, the air flow rate control is divided and performed by group. Accordingly, in this embodiment, the total flow rate detection step (S602), the valve opening control step (S603), and the supply flow rate control step (S604), etc., may be performed for each divided group.

[0082] For example, if the unit flow rate change is denoted as 'q' and the time for performing valve control is denoted as T, the total flow rate change (Q) during time T is the sum of the unit flow rate changes 'q' for each stack. In this case, if flow rate reduction control or flow rate increase control is required uniformly for multiple stacks, the total flow rate change (Q) may become excessively large. Since this can cause the flow rate change of fuel cell stacks that are not subject to flow rate control to become excessively large, it is unsuitable for a stable operating environment for fuel cell stacks.

[0083] Accordingly, in a preferred embodiment of the present invention, in order to prevent the total flow rate change (Q) from becoming excessively large, the system may be configured to determine whether the total flow rate change (Q) of the stacks to be controlled at the control time (T) exceeds a preset reference flow rate. If, as a result of the determination, the sum of the required flow rate changes within the control time, i.e., the total flow rate change (Q), exceeds the reference flow rate, the fuel cell stacks to be controlled for air flow rate control are divided into multiple groups to control the flow rate so that the total flow rate change (Q) is within the reference flow rate. Accordingly, the fuel cell stacks are controlled such that control schedules are separated by divided groups, and flow rate control for the groups assigned to each control schedule is performed sequentially. In this regard, the reference flow rate may be appropriately selected considering the operational stability of the fuel cell stacks, and may also be a variable value dependent on the number of remaining stacks for which flow rate changes are unnecessary.

[0084] Specific examples of this can be explained through FIGS. 7a to 7c.

[0085] FIGS. 7a to 7c illustrate an example in which air flow control of multiple stacks is performed simultaneously in 10 fuel cell stacks.

[0086] First, FIG. 7a is an example in which the air flow rate of multiple stacks can be controlled simultaneously based on the absolute value of the total flow rate change. Referring to FIG. 7a, stacks 1, 2, 4, 8, and 9 require flow rate increase control by a unit flow rate change 'q', while stacks 3, 5, 6, and 7 require flow rate decrease control by a unit flow rate change 'q'. Meanwhile, stack 10 is a stack that does not require change.

[0087] In the case of Fig. 7a, the total flow rate change (Q) is only 'q', and therefore the absolute value of the total flow rate change (Q) is not excessively large, so the effect on stack 10, which does not change the flow rate, is minimal, and therefore it can be said to be an example where air flow rate control for 9 stacks is possible simultaneously.

[0088] On the other hand, FIG. 7b illustrates an example where air flow control of multiple stacks is impossible based on the absolute value of the total flow rate change. That is, in the example of FIG. 7b, stack 10 is a stack that does not require change, and among the stacks requiring flow rate control, only stack 6 requires flow rate reduction control by a unit flow rate change 'q'. Meanwhile, stacks 1 through 5 and 7 through 9 require flow rate increase control by a unit flow rate change 'q'.

[0089] Therefore, in the example of FIG. 7b, the total flow rate change (Q) becomes '7q', and in this case, since the absolute value of the total flow rate change (Q) becomes excessively large, a problem arises in which the impact on stack 10, which does not perform flow rate control, becomes large. In a preferred embodiment of the present invention, this problem is to be solved by performing flow rate control for each stack in a divided manner.

[0090] In this regard, FIG. 7c illustrates an example in which air flow control is divided and performed by section when flow control as in FIG. 7b is required.

[0091] In the example of Fig. 7c, air flow control for stacks 1 to 3 is performed during the divided time T1, air flow control for stacks 4 to 6 is performed during the time T2, and air flow control for stacks 7 to 9 is performed separately during the time T3.

[0092] For example, during the control time of T1, the total flow rate change (Q) is reduced to '3q', and the number of stacks where no air flow rate change occurs increases from one stack (Stack No. 10) to a total of seven stacks (Stacks No. 4 through 10), so there is an effect of significantly reducing the flow rate change for each fuel cell stack.

[0093] Although specific embodiments of the present invention have been illustrated and described, it will be obvious to those skilled in the art that the present invention can be modified and changed in various ways without departing from the technical spirit of the invention as provided by the following claims. Explanation of the symbols

[0095] 10: Air supply unit 21, 22, 23, 24: Flow meter 31, 32, 33, 34: Valves 40: Controller 51, 52, 53, 54: Fuel cell stack

Claims

Claim 1 An air supply device for an integrated fuel cell stack, comprising: an air supply unit for supplying air to a plurality of fuel cell stacks; a plurality of pipes configured to deliver air supplied from the air supply unit to each fuel cell stack; a plurality of valves installed in each pipe and configured to control the flow rate of air flowing through each pipe; a plurality of flow meters for measuring the flow rate of air flowing through each pipe; and a controller capable of controlling the opening amount of the valves based on flow rate information measured by the flow meters; wherein the controller controls the opening amount of the valves installed in each pipe to enable air flow rate control for each pipe, and the controller is configured to enable initial setting control of the opening amount of the valves, and during the initial setting control, all valves are opened and the air supply unit operates at a preset calibration rotational speed, wherein the opening amount of the valves is controlled by the controller to extract information on the opening amount of the valves such that the flow rate deviation in each pipe meets within a preset standard, and the controller stores the extracted valve opening amount information as an initial setting. Claim 2 delete Claim 3 An air supply device for an integrated fuel cell stack according to claim 1, wherein the controller, during the initial setting control, adjusts the opening of the valve on the pipe side through which the maximum flow rate flows in the closing direction based on flow rate information measured by each flow meter, and controls the opening amount of the valve on the maximum flow rate pipe side to reduce the flow rate deviation one or more times so that the flow rate of the maximum flow rate pipe approaches the average flow rate information, which is the average value of the values ​​measured by each flow meter. Claim 4 An air supply unit for supplying air to a plurality of fuel cell stacks; a plurality of pipes configured to deliver air supplied from the air supply unit to each fuel cell stack; a plurality of valves installed in each pipe and configured to control the air flow rate through each pipe; a plurality of flow meters for measuring the air flow rate through each pipe; An air supply device for an integrated fuel cell stack, comprising: a controller capable of controlling the opening amount of the valves based on flow rate information measured by the flow meters; wherein the controller controls the opening amount of the valve installed in each pipe to enable air flow rate control for each pipe, and the controller is configured to adjust the supply flow rate supplied from the air supply unit; wherein, when equal air flow rate control for all fuel cell stacks is required, the air flow rate supplied through each pipe is measured by each flow meter while the flow rate supplied from the air supply unit is adjusted, and the controller controls the opening of the valve on the pipe side where the maximum flow rate flows to the closing direction based on the flow rate information measured by each flow meter so as to reduce the flow rate deviation between the flow rate of the maximum flow rate pipe and the average flow rate information, which is the average value of the values ​​measured by each flow meter, and wherein the controller repeats the average flow rate measurement and flow rate deviation reduction control until the flow rate deviation in each pipe meets within a preset standard. Claim 5 An air supply device for an integrated fuel cell stack according to claim 4, wherein the controller determines whether a required flow rate value for each fuel cell stack has been reached based on flow rate information measured by each flow meter, and if the required flow rate value for each fuel cell stack has not been reached even if the flow rate deviation in each pipe meets within a preset standard, the controller repeatedly performs supply air flow rate control, average flow rate measurement, and flow rate deviation reduction control of the air supply unit until the required flow rate value is reached. Claim 6 An air supply unit for supplying air to a plurality of fuel cell stacks; a plurality of pipes configured to deliver air supplied from the air supply unit to each fuel cell stack; a plurality of valves installed in each pipe and configured to control the air flow rate through each pipe; a plurality of flow meters for measuring the air flow rate through each pipe; An air supply device for an integrated fuel cell stack, comprising: a controller capable of controlling the opening amount of the valves based on flow rate information measured by the flow meters; wherein the controller controls the opening amount of the valve installed in each pipe to enable air flow rate control for each pipe, and the controller is configured to adjust the supply flow rate supplied from the air supply unit; wherein, when air flow rate control for a specific fuel cell stack is required, the total flow rate of air supplied to the remaining fuel cell stacks excluding the fuel cell stack for which the flow rate is to be controlled is measured and stored, and the controller measures the total flow rate of air supplied to the remaining fuel cell stacks in real time while controlling the opening of the valve for the fuel cell stack for which the flow rate is to be controlled according to the required air flow rate, and performs air flow rate control for the specific fuel cell stack by repeating the process of adjusting the supply flow rate supplied from the air supply unit at least once until the total flow rate for the remaining stacks measured in real time reaches the total flow rate for the remaining stacks stored in advance. Claim 7 An air supply unit for supplying air to a plurality of fuel cell stacks; a plurality of pipes configured to deliver air supplied from the air supply unit to each fuel cell stack; a plurality of valves installed in each pipe and configured to control the air flow rate through each pipe; a plurality of flow meters for measuring the air flow rate through each pipe; An air supply device for an integrated fuel cell stack, comprising: a controller capable of controlling the opening amount of the valves based on flow rate information measured by the flow meters; wherein the controller controls the opening amount of the valve installed in each pipe to enable air flow rate control for each pipe, and the controller is configured to adjust the supply flow rate supplied from the air supply unit; wherein, when air flow rate control for two or more specific fuel cell stacks is required, the total flow rate of air supplied to the remaining fuel cell stacks excluding the two or more fuel cell stacks for which the flow rate is to be controlled is measured and stored, and the controller measures the total flow rate of air supplied to the remaining fuel cell stacks in real time while controlling the opening of the valves for the fuel cell stacks for which the flow rate is to be controlled according to the required air flow rate, and performs air flow rate control for the specific fuel cell stacks by repeating the process of adjusting the supply flow rate supplied from the air supply unit one or more times until the total flow rate for the remaining stacks measured in real time reaches the total flow rate for the remaining stacks stored in advance. Claim 8 An air supply device for an integrated fuel cell stack according to claim 7, characterized in that when the sum of the flow rate changes for each fuel cell stack requiring air flow rate control exceeds a preset reference flow rate, the controller divides the air flow rate control so that the sum of the flow rate changes for each fuel cell stack is within the preset reference flow rate. Claim 9 An air supply unit for supplying air to a plurality of fuel cell stacks; a plurality of pipes configured to deliver air supplied from the air supply unit to each fuel cell stack; a plurality of valves installed in each pipe and configured to control the air flow rate through each pipe; a plurality of flow meters for measuring the air flow rate through each pipe; A method for controlling air flow using an air supply device of an integrated fuel cell stack capable of controlling the opening amount of the valves based on flow information measured by the flow meters, wherein the controller controls the opening amount of the valves installed in each pipe to enable air flow control for each pipe, the method comprising, prior to operation of the fuel cell stack, an initial setting control process for the opening amount of the valves by the controller, wherein in the initial setting control process, while all valves are open and the air supply unit is operating at a preset calibration rotational speed, the opening amount of the valves is controlled by the controller to extract information on the opening amount of the valves such that the flow deviation in each pipe meets within a preset standard, and wherein the controller stores the extracted information on the opening amount of the valves as an initial setting. Claim 10 The air flow control method according to claim 9, wherein the initial setting control process comprises: a starting step in which all valves are opened and the air supply unit operates at a preset calibration rotational speed; an average flow rate calculation step for calculating average flow rate information based on flow rate information measured by each flow meter; a valve opening control step for adjusting the opening of the valve on the pipe side through which the maximum flow rate flows in the closing direction; a flow rate deviation checking step for checking whether the maximum flow rate deviation determined from the difference between the flow rate value of the maximum flow rate pipe reduced according to the valve opening control step and the average flow rate information is within a preset standard; and a step of extracting the opening amount information of each valve and storing it as an initial setting when the maximum flow rate deviation is within a preset standard. Claim 11 An air flow control method according to claim 10, wherein in the flow rate deviation checking step, if the maximum flow rate deviation deviates from a preset standard, the average flow rate calculation step, the valve opening control step, and the flow rate deviation checking step are repeated until the maximum flow rate deviation reaches within the preset standard. Claim 12 An air supply unit for supplying air to a plurality of fuel cell stacks; a plurality of pipes configured to deliver air supplied from the air supply unit to each fuel cell stack; a plurality of valves installed in each pipe and configured to control the air flow rate through each pipe; a plurality of flow meters for measuring the air flow rate through each pipe; A method for controlling air flow using an air supply device of an integrated fuel cell stack capable of controlling the air flow rate for each pipe by controlling the opening amount of the valves based on flow rate information measured by the flow meters, wherein the controller controls the opening amount of the valve installed in each pipe to enable air flow rate control for each pipe, the method comprises: a supply flow rate control step for controlling the flow rate supplied from the air supply unit when a demand for uniform air flow rate control for all fuel cell stacks occurs during the operation of the fuel cell stack; an average flow rate calculation step for calculating average flow rate information by measuring the air flow rate supplied through each pipe by each flow meter; a valve opening control step for controlling the opening of the valve on the pipe side where the maximum flow rate flows in the closing direction; and a flow rate deviation verification step for verifying whether the maximum flow rate deviation determined from the difference between the flow rate value of the maximum flow rate pipe reduced according to the valve opening control step and the average flow rate information is within a preset standard. An air flow control method characterized by including: a step of confirming whether a required flow rate value has been reached for each fuel cell stack based on flow rate information measured by each flow meter. Claim 13 An air flow control method according to claim 12, wherein if it is confirmed through the flow rate deviation verification step that the maximum flow rate deviation deviates from a preset standard, the average flow rate calculation step, the valve opening control step, and the flow rate deviation verification step are repeated until the maximum flow rate deviation reaches within the preset standard, and if it is confirmed through the required flow rate attainment verification step that the required flow rate value for each fuel cell stack is not reached, the air supply flow rate from the air supply unit is readjusted according to the required flow rate value, and the steps below the average flow rate calculation step are repeated. Claim 14 A method for controlling air flow using an air supply device of an integrated fuel cell stack, comprising: an air supply unit for supplying air to a plurality of fuel cell stacks; a plurality of pipes configured to deliver air supplied from the air supply unit to each fuel cell stack; a plurality of valves installed in each pipe and configured to control the air flow rate flowing through each pipe; a plurality of flow meters for measuring the air flow rate flowing through each pipe; and a controller capable of controlling the opening amount of the valves based on flow rate information measured by the flow meters; wherein the controller controls the opening amount of the valves installed in each pipe to enable air flow rate control for each pipe, the method comprises: a total flow rate detection step of measuring and storing the total flow rate of air supplied to the remaining fuel cell stacks excluding the fuel cell stack whose flow rate is to be controlled when a request for air flow rate control for a specific fuel cell stack occurs during the operation of the fuel cell stack; and a valve opening control step of controlling the opening of the valve for the fuel cell stack whose flow rate is to be controlled according to the required air flow rate. A method for controlling air flow rate, comprising: a supply flow rate control step of measuring the total flow rate of air supplied to the remaining fuel cell stacks in real time, and controlling the supply flow rate supplied from the air supply unit until the total flow rate for the remaining stacks measured in real time reaches the total flow rate for the remaining stacks stored in advance. Claim 15 An air flow control method using an air supply device for an integrated fuel cell stack, comprising: an air supply unit for supplying air to a plurality of fuel cell stacks; a plurality of pipes configured to deliver air supplied from the air supply unit to each fuel cell stack; a plurality of valves installed in each pipe and configured to control the air flow rate flowing through each pipe; a plurality of flow meters for measuring the air flow rate flowing through each pipe; and a controller capable of controlling the opening amount of the valves based on flow rate information measured by the flow meters; wherein the controller controls the opening amount of the valves installed in each pipe to enable air flow rate control for each pipe, the method comprises: a total flow rate detection step of measuring and storing the total flow rate of air supplied to the remaining fuel cell stacks excluding the two or more fuel cell stacks whose flow rate is to be controlled when a request for air flow rate control for two or more specific fuel cell stacks occurs during the operation of the fuel cell stacks; and a valve opening control step of controlling the opening of the valves for the two or more fuel cell stacks whose flow rate is to be controlled according to the required air flow rate. A method for controlling air flow rate, comprising: a supply flow rate control step of measuring the total flow rate of air supplied to the remaining fuel cell stacks in real time, and controlling the supply flow rate supplied from the air supply unit until the total flow rate for the remaining stacks measured in real time reaches the total flow rate for the remaining stacks stored in advance.

Images