Adaptive purge for fuel cell system

Abstract

Aspects of an adaptive purge technique for purging a fuel cell are disclosed herein that adjusts a time delay between subsequent purges based in part on one or more parameters of the fuel cell. The difference between two similar parameters is measured before and after actuation of a valve for allowing purge gas to enter. The degree of difference between the two parameters is used to determine a time delay, i.e., the time at which the valve should be re-actuated to allow the fuel cell to perform the next purge. In addition to the time delay, the parameters may also be used to determine a time interval or duration during which the valve is actuated to remain open during the purge event.

Description

Technical Field

[0001] This application is a PCT application that claims priority to UK Patent Application No. 2213374.8, filed on September 13, 2022, the entire disclosure of which is incorporated herein by reference as if set forth in full herein.

[0002] This application relates to fuel cell systems, and more particularly, to adaptively managing control valves for purging one or more fuel cells in a fuel cell system. Background Art

[0003] Conventional electrochemical fuel cells convert fuel and oxidant into electrical energy and reaction products. Common types of electrochemical fuel cells include membrane electrode assemblies (MEAs) that include a polymer ion (proton) transfer membrane between an anode and a cathode flow path or gas diffusion structure. Fuel (such as hydrogen) and oxidant (such as oxygen in air) pass over respective sides of the MEA to produce electrical energy and water as reaction products. A stack can be formed that includes a plurality of such fuel cells arranged with separate anode and cathode fluid flow paths. Such stacks are typically in block form and include many individual fuel cell plates held together by end plates at opposite ends of the stack.

[0004] It is very important for the polymer ion transfer membrane to remain hydrated for efficient operation. Controlling the temperature of the stack is also important. Thus, coolant can be supplied to the stack for cooling and / or hydration. It may be necessary to purge the coolant, contaminants, or reaction by-products from the fuel cell flow path or gas diffusion structure at specific times or periodically using a purge gas.

[0005] Water and other gases should be purged (i.e., removed) from the fuel cell periodically. The gas to be removed, which can include fuel (e.g., hydrogen), flows through the anode flow path to remove water and gas from the fuel cell. Conventional fuel cells are set to provide this removal process at a specified time regardless of whether removal is needed at that particular time. This can lead to inefficient use of the gas for removing water, especially when the gas is also used to generate electrical energy. Summary of the Invention

[0006] According to one aspect of the present disclosure, there is provided a fuel cell system comprising: a fuel cell assembly including an anode exhaust and a fuel cell; a valve configured to discharge a purge gas from the anode exhaust; and a valve controller configured to: obtain a first parameter of the fuel cell before a first purge of the fuel cell with the purge gas; obtain a second parameter of the fuel cell after the first purge; obtain a difference between the first parameter and the second parameter; and determine a time delay for a second purge after the first purge based on the difference.

[0007] According to another aspect of the present disclosure, a fuel cell system is provided, which includes: a fuel cell assembly including an anode exhaust device and a fuel cell; a valve configured to discharge a purge gas from the anode exhaust device; and a valve controller configured to: before a first purge of the fuel cell with the purge gas, obtain a first parameter of the fuel cell; after the first purge, obtain a second parameter of the fuel cell; obtain a difference between the first parameter and the second parameter; and, based on the difference, determine a purge duration during which the valve remains open for a second purge after the first purge.

[0008] According to a further aspect of the present disclosure, a fuel cell system is provided, which includes: a fuel cell assembly including an anode exhaust device and a fuel cell; a valve configured to discharge a purge gas from the anode exhaust device; and a valve controller configured to: before a first purge of the fuel cell with the purge gas, obtain a first parameter of the fuel cell; after the first purge, obtain a second parameter of the fuel cell; obtain a difference between the first parameter and the second parameter; and, based on the difference, perform a purge cluster that includes a series of opening and subsequent closing of the valve for a predetermined number of times.

[0009] In any of the above aspects of the present disclosure, the first parameter may include a first output voltage, a first temperature, a first humidity, or a first current of the fuel cell, and the second parameter may include a second output voltage, a second temperature, a second humidity, or a second current of the fuel cell, respectively. In some aspects, the first parameter may include a first altitude or a first humidity of the fuel cell, and the second parameter may include a second altitude or a second humidity of the fuel cell, respectively.

[0010] In some aspects, the present disclosure also describes an adaptive purge technique for purging a fuel cell that adjusts the time delay between subsequent purges based in part on one or more parameters of the fuel cell. Before and after actuating a valve that allows the purge gas to pass, the difference between two similar parameters is measured. The degree of difference between the two parameters is used to determine the time delay, i.e., the time at which the valve should be actuated again to allow the fuel cell to undergo the next purge. In addition to the time delay, the parameters can also be used to determine the time interval or duration during which the valve is actuated to remain open during a purge event. Optionally, or in combination, a purge cluster can also be implemented by opening and closing the valve a predetermined number of times. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Certain features of the subject technology are set forth in the appended claims. However, for explanatory purposes, several examples of the subject technology are set forth in the figures below.

[0012] Figure 1 A schematic diagram of a fuel cell system in accordance with various aspects of the present disclosure is shown, the system including a fuel cell assembly, an exhaust assembly, and a control valve.

[0013] Figure 2A and 2B An example valve that can be actuated in two operating positions is shown in accordance with various aspects of the present disclosure.

[0014] Figure 3 An example valve that can be actuated in two operating positions is shown in accordance with various aspects of the present disclosure.

[0015] Figure 4 A schematic diagram of an alternative fuel cell system in accordance with various aspects of the present disclosure is shown.

[0016] Figure 5 A schematic diagram of an alternative fuel cell system having multiple valves in accordance with various aspects of the present disclosure is shown.

[0017] Figure 6 A method for adaptively purging a fuel cell in accordance with various aspects of the present disclosure is shown.

[0018] Figure 7 An alternative method for adaptively purging a fuel cell in accordance with various aspects of the present disclosure is shown. DETAILED DESCRIPTION

[0019] The following disclosure is intended to describe various configurations of the present subject matter and is not intended to represent the only configuration for practicing the present subject matter. The drawings are incorporated herein and constitute a part of the detailed description. The present disclosure includes specific details for the purpose of providing a thorough understanding of the present subject matter. However, it will be apparent to those of ordinary skill in the art that the present subject matter is not limited to the specific details described herein and may be practiced without these specific details. In some instances, well-known structures and components are shown in block diagram form to avoid obscuring the concepts of the present subject matter.

[0020] The present subject matter relates to adaptively purging a fuel cell based on various selected parameters of the fuel cell. For example, the time delay between valve actuations (e.g., opening) or the purge time delay can vary in part based on the difference between two measured parameters. In particular, the valve controller utilizes the degree of difference between two measured parameters (e.g., a larger difference or a smaller difference) to determine when to actuate the valve for a subsequent purge event. As used herein, "difference" can include the absolute value of the difference. Advantageously, the valve is actuated when purging of the fuel cell is required, rather than at a predetermined time interval when purging may not be needed.

[0021] Several parameters can be selected to determine the adaptive purge. As non-limiting examples, the parameters can include voltage, temperature, current, altitude, humidity (of the incoming air), gas quality, and hydration. In one exemplary embodiment, the voltage output of the fuel cell is measured before opening the valve to purge the fuel cell. After opening the valve, the voltage output of the fuel cell is measured again. The Δ (delta) or difference between the two measured voltages can be used to determine the time delay for subsequent valve openings (including the next valve opening) to purge the fuel cell. In this regard, when the difference in the measured voltage output is relatively high (e.g., 20 millivolts (mV)), the time delay can be relatively short (e.g., 30 seconds (s)). Conversely, when the difference in the measured voltage output is relatively low (e.g., 5 mV), the time delay can be relatively long (e.g., 120 s). Thus, the time delay can be inversely proportional to the difference between the measured parameters.

[0022] In addition to the adaptive purge time delay between valve actuation events for purging, additional time parameters can be incorporated. For example, the time the valve is open (e.g., the time between opening and closing) represents the purge duration and can be partially based on the aforementioned parameter variations. Thus, the fuel cell system can actuate the valve in such a way that not only can the time between subsequent valve openings be adjusted, but also the time the valve remains open.

[0023] The fuel cell system with adaptive purge capabilities described herein offers several advantages. For example, when the gas used to purge the fuel cell is also used to generate electrical energy, gas can be saved since adaptive purge is a predictive technique rather than a traditional technique with a predetermined time interval between purge events.

[0024] According to aspects of some examples, such as Figure 1 shown, the fuel cell system 100 includes a fuel cell assembly 102 and a control valve 104 for controlling the exhaust flow of the purge gas, or simply referred to as the valve. Thus, the control valve 104 can be referred to as a purge control valve and forms part of an exhaust assembly that is configured to receive fluids exiting through the anode flow path of the fuel cell assembly 102 and through the cathode flow path of the fuel cell assembly 102. During a purge operation, a gas, such as fuel (e.g., hydrogen), flows through the anode flow path to purge the coolant, hydrated fluid, contaminants, and / or reaction by-products of the anode flow path. The control valve 104 is configured to control the exhaust flow of the purge gas exiting the fuel cell assembly 102.

[0025] The fuel cell assembly 102 in this example includes a fuel cell stack, which includes a plurality of proton exchange membrane fuel cells stacked together. The fuel cell assembly 102 is configured to receive a fuel stream such as hydrogen through the anode inlet 106 and an oxidant stream such as air through the cathode inlet 108. An anode exhaust device 110 is provided to allow the flow of unused fuel and purge gas. A cathode exhaust device 112 is provided to allow the flow of the oxidant stream. The control valve 104 is connected to the anode exhaust device 110 and includes a two-port, two-position valve. A schematic diagram of the control valve 104 is as Figure 1 shown, and example valve positions are as Figure 2A and 2B shown.

[0026] Referring to Figure 2A and 2B , the control valve 104 includes a valve body 116, which contains a valve member 118. The valve member 118 is slidably mounted in the valve body 116 and can move between a first position ( Figure 2A ) and a second position ( Figure 2B ). The valve body 116 includes an inlet port 120 for receiving the purge gas discharged from the fuel cell assembly 102 (as Figure 1 shown) and an outlet port 122 for providing an outlet for the purge gas.

[0027] In the first position ( Figure 2A ), the valve member 118 functions to prevent the discharged purge gas (shown in dashed lines) from flowing between the inlet port 120 and the outlet port 122. In the second position ( Figure 2B ), the valve member 118 allows the purge gas to flow between the inlet port 120 and the outlet port 122. Thus, the valve member 118 is configured to close the inlet port 120 in its first position and open the inlet port 120 in its second position. In particular, the inlet port 120 includes a valve seat 124, and in the first position, the sealing surface 126 of the valve member 118 seals on the valve seat 124. When the sealing surface 126 of the valve member 118 is not engaged with the valve seat 124 (as Figure 2B shown), the purge gas is allowed to flow through the control valve 104.

[0028] The valve member 118 is biased to the first position by a biasing device, which may include a spring as a non-limiting example. The control valve 104 may include an electromagnetic valve, and thus the valve member 118 can be moved between its first and second positions by the actuation of an electromagnetic valve (not shown), which is configured to move the valve member 118 to the second position against the force of the biasing device.

[0029] Referring to Figure 1During a purge operation, fuel may flow through the anode flow path of the fuel cell assembly 102. The control valve 104 may be actuated by a solenoid valve to move the valve member 118 from a first position to a second position, which may allow purge gas to flow through the fuel cell assembly 102.

[0030] Reference Figure 3 The fuel cell assembly 202 includes n fuel cells, which have fuel cell 230a, fuel cell 230b, fuel cell 230c, and fuel cell 230n. In this regard, the fuel cell assembly 202 may include a fuel cell stack composed of fuel cells 230a to 230n. In addition, fuel cells 230a and 230n may be referred to as end cells because fuel cells 230a and 230n represent the two outermost fuel cells.

[0031] In addition, the fuel cell assembly 202 includes one or more sensors 232, which are designed to monitor at least one of the fuel cells 230a to 230n. In some instances, the one or more sensors 232 include a voltmeter, which is designed to determine the output voltage of at least one of the fuel cells 230a to 230n. In addition, in some instances, the one or more sensors 232 include a temperature sensor, which is designed to measure the temperature of at least one of the fuel cells 230a to 230n. Still further, in some instances, the one or more sensors 232 include a barometric pressure sensor, which is designed to measure the pressure (e.g., ambient pressure) of at least one of the fuel cells 230a to 230n. In this regard, the one or more sensors 232 may determine the height of the fuel cell assembly 202 (i.e., relative to sea level) based on the measured pressure. As an alternative to the barometric pressure sensor, the one or more sensors 232 may include an altimeter for determining altitude. In addition, in some instances, the one or more sensors 232 include a humidity sensor, which is designed to measure the relative humidity of the air entering at least one of the fuel cells 230a to 230n. Additionally, in some instances, the one or more sensors 232 include a gas analyzer, which is designed to measure the gas composition, which may be used to determine the purity / quality of the gas in at least one of the fuel cells 230a to 230n. Additionally, in some instances, the one or more sensors 232 include a hydration sensor, which is designed to measure the amount of liquid in at least one of the fuel cells 230a to 230n.

[0032] Reference Figure 4, the fuel cell system 300 includes a fuel cell assembly 302 and a control valve 304 actuated by a controller 334. The fuel cell assembly 302 includes a fuel cell 330 and one or more sensors 332 that monitor the fuel cell 330. The one or more sensors 332 can include any of the above-described sensors herein. Additionally, as shown, the one or more sensors 332 are integrated with the fuel cell assembly 302. However, it should be noted that the one or more sensors 332 can be separated from the fuel cell assembly 302 while still monitoring the fuel cell 330 and communicating with the controller 334.

[0033] The controller 334 includes a memory 336, which represents one or more storage circuits that store executable code or executable instructions. The controller 334 further includes a processor 338, which represents a processing circuit in the form of a central processing unit, a programmable logic circuit, and / or an application-specific integrated circuit. The processor 338 is designed to execute the instructions / code stored on the memory 336. For example, the processor 338 can use the instructions stored on the memory 336 to actuate (i.e., open and close) the control valve 304. When the controller 334 opens the control valve 304, a gas 340 passes through the fuel cell assembly 302 to purge the fuel cell 330. As a non-limiting example, the gas 340 can include hydrogen.

[0034] Additionally, the processor 338 can be used to send instructions stored on the memory 336 to obtain data (e.g., numerical values) from the one or more sensors 332. In this regard, the controller 334 can receive data from the one or more sensors 332 by periodically (e.g., on the order of milliseconds or seconds) requesting the data, or continuously receive updated data from the one or more sensors 332. In some instances, the controller 334 obtains data from the one or more sensors 332 before and after actuating the control valve 304. For example, before the controller 334 opens the control valve 304, the controller 334 can obtain data from the one or more sensors 332. Additionally, after the controller 334 closes the control valve 304, the controller 334 can obtain data (i.e., updated data) from the one or more sensors 332.

[0035] In an exemplary instance, the one or more sensors 332 include at least one voltmeter, which is designed to monitor and determine the output voltage of the fuel cell 330. Before the controller 334 opens the control valve 304, the controller 334 can obtain the output voltage from the one or more sensors 332. Additionally, after the controller 334 closes the control valve 304, the controller 334 can obtain the output voltage from the one or more sensors 332. The opening and closing of the control valve 304 represents a purge event.

[0036] Using the memory 336 and the processor 338, the controller 334 can determine the difference between two output voltages and determine the time delay to provide instructions to the control valve 304 for subsequent purge events. In other words, the controller 334 uses the output voltage difference to determine when to initiate the next purge event. The time delay between consecutive purge events can be inversely proportional. For example, when the output voltage difference is relatively small, the time delay is relatively long; conversely, when the output voltage difference is relatively large, the time delay is relatively short. The process can include an iterative process that compares the difference between consecutive output voltages during a purge event and adjusts the time delay for the next purge event. Advantageously, the fuel cell system 300 includes an adaptive purge technique that anticipates subsequent purges, which can reduce the number of purge events to conserve gas 340, or alternatively increase the number of purge events to operate the fuel cell assembly 302 (particularly the fuel cell 330) more effectively, thereby facilitating an increase in energy output and / or limiting or preventing damage to the fuel cell assembly 302.

[0037] Additionally, in some instances, when the difference between two parameters (e.g., the difference between two measured output voltages) is below a threshold difference, the controller 334 does not adaptively adjust the time delay. In other words, for subsequent purges, the change in the time delay is zero seconds, and the previous time delay is used.

[0038] Generally, the foregoing instances can be implemented in a similar manner with different sensors. For example, when one or more sensors 332 include at least one temperature sensor that monitors and determines the temperature of the fuel cell 330, the controller 334 can obtain voltages from one or more sensors 332 before opening the control valve 304 and after the control valve 304 is closed, determine the temperature difference between the two obtained temperatures, and determine the time delay based on the temperature difference. Optionally, the measured temperature can be compared with a set of ideal temperatures on a curve (e.g., a bell curve), and the time delay is based on the deviation from the curve.

[0039] In another instance, when one or more sensors 332 include an ammeter, the measured current can be compared with a range (such as an optimal range), and the time delay is based on the deviation from the range.

[0040] Other instances of one or more sensors 332 include a barometric pressure sensor, an altimeter, a humidity sensor, a gas analyzer, and / or a hydration sensor. In a similar manner, the controller 334 can obtain respective data from alternative instances of one or more sensors 332 before opening the control valve 304 and after closing the control valve 304, determine the difference between the two obtained data, and determine a time delay based on the determined difference. The time delay can again be inversely proportional to the determined difference. For example, when the altitude difference (determined by the barometric pressure sensor or altimeter) is relatively large, the time delay between consecutive purge events may be reduced. Similarly, when the humidity difference (determined by the humidity sensor) is relatively large, the time delay between consecutive purge events may be reduced.

[0041] As an alternative to or in combination with the time delay between consecutive purge events, the duration of a purge event can be adjusted adaptively. The duration of a purge event can refer to the time between (and including) the opening and subsequent closing of the control valve 304. For example, the controller 334 can use the output voltage difference to determine the duration of a purge event for a subsequent purge event (or events), including the next purge event. By further adaptively controlling the control valve 304 to reduce the purge duration, the gas 340 can be saved. Optionally, by further adaptively controlling the control valve 304 to increase the purge duration, the fuel cell assembly 302 (particularly the fuel cell 330) operates more efficiently to promote an increase in energy output, and / or to prevent damage. It should be noted that, in addition to the voltmeter, the purge duration can also be associated with the implementation of any instance of one or more sensors 332.

[0042] Reference Figure 5 , the fuel cell system 400 includes a plurality of fuel cell assemblies. As shown, the fuel cell system 400 includes n fuel cell assemblies and n control valves. The fuel cell assemblies 402a, 402b, and 402n are shown. The fuel cell assembly 402a includes a fuel cell 430a and one or more sensors 432a. The fuel cell assembly 402b includes a fuel cell 430b and one or more sensors 432b. The fuel cell assembly 402n includes a fuel cell 430n and one or more sensors 432n. The one or more sensors 432a, 432b, and 432n can include any of the above sensors described herein.

[0043] In addition, control valves 404a, 404b, and 404n are used to allow gas 440 to purge fuel cells 430a, 430b, and 430n, respectively. The fuel cell system 400 further includes a controller 434 that is used to actuate each of the control valves 404a, 404b, and 404n to purge fuel cells 430a, 430b, and 430n, respectively. Additionally, as shown, one or more sensors 432a, 432b, and 432n are integrated with fuel cell assemblies 402a, 402b, and 402n, respectively. However, it should be noted that one or more sensors 432a, 432b, and 432n can be separated from fuel cell assemblies 402a, 402b, and 402n while still monitoring fuel cells 430a, 430b, and 430n, respectively, and still communicating with the controller 434.

[0044] The controller 434 includes a memory 436, which represents one or more storage circuits that store executable code or executable instructions. The controller 434 further includes a processor 438, which represents a processing circuit in the form of a central processing unit, a programmable logic control circuit, and / or an application-specific integrated circuit. The processor 438 is designed to execute the instructions / code stored on the memory 436. For example, the processor 438 can use the instructions stored on the memory 436 to actuate (i.e., open and close) the control valves 404a, 404b, and 404n. When the controller 434 opens the control valves 404a, 404b, and 404n, the gas 440 passes through the fuel cell assemblies 402a, 402b, and 402n, respectively, to purge the fuel cells 430a, 430b, and 430n. As a non-limiting example, the gas 440 can include hydrogen. Additionally, the controller 434 is designed to actuate the control valves 404a, 404b, and 404n independently. In this way, the fuel cells 430a, 430b, and 430n can be purged independently.

[0045] Additionally, the processor 438 can be used to send instructions stored in the memory 436 to obtain data from one or more of the sensors 432a, 432b, and 432n in the manner described above. Thus, the controller 434 can adaptively purge each of the fuel cells 430a, 430b, and 430n in an independent manner. For example, the time delays between consecutive purge events for each of the fuel cells 430a, 430b, and 430n can be different from each other, or two or more of the fuel cells 430a, 430b, and 430n can include the same time delay between consecutive purge events based on data from one or more of the sensors 432a, 432b, and 432n. Advantageously, the fuel cell assemblies 402a, 402b, and 402n can be managed independently, which can improve the hardware efficiency of the controller 434 (i.e., the processor 438) and / or save gas 440.

[0046] As an alternative to or in combination with the time delay between consecutive purge events, the duration of the purge event can be adjusted adaptively. For example, the controller 434 uses data from one or more of the sensors 432a, 432b, and 432n to determine the duration of the purge event for subsequent purge events of the fuel cells 430a, 430b, and 430n, respectively. By further adaptively controlling the control valves 404a, 404b, and 404n to reduce the purge duration, gas 440 can be saved. Optionally, by further adaptively controlling the control valves 404a, 404b, and 404n to increase the purge duration, the fuel cell assemblies 402a, 402b, and 402n can operate more efficiently to promote an increase in energy output and / or prevent damage.

[0047] Reference Figure 6 , a method 500 for adaptively purging a fuel cell is shown. The various steps of the method 500 can be performed by the controller of the fuel system shown and described herein.

[0048] In step 502, before performing the first purge, a first parameter of the fuel cell is obtained. "Purge" refers to an event that allows a gas (e.g., a purge gas) to enter and remove unwanted liquids (e.g., water) and gases (e.g., nitrogen). The first parameter of the fuel cell can be measured / monitored by a sensor. As a non-limiting example, the sensor can include a voltmeter, a temperature sensor, a barometric pressure sensor, an altimeter, a humidity sensor, a gas analyzer, or a hydration sensor. The controller can obtain data related to the first parameter from the sensor.

[0049] In step 504, after performing the first purge, a second parameter of the fuel cell is obtained. Similar to the first parameter, the controller can obtain data related to the second parameter from a sensor. Additionally, the same sensor used to measure / monitor the first parameter can also be used to measure / monitor the second parameter.

[0050] In step 506, the difference between the first parameter and the second parameter is obtained. The difference can include subtracting the first parameter value of the first parameter from the second parameter value of the second parameter. Optionally, the difference can include the deviation from an ideal parameter (or ideal parameter range), which is determined by a curve / graph.

[0051] In step 508, based on the difference, the time delay for the second purge after the first purge is determined. The time delay can represent the time when the controller starts to perform the second or next purge after the first purge.

[0052] Reference Figure 7 , shows a method 600 for adaptively purging a fuel cell. Each step of method 600 can be performed by the controller of the fuel system shown and described herein.

[0053] In step 602, before the first purge, a first parameter of one or more fuel cells is obtained. "Purge" represents an event that allows a gas (e.g., purge gas) to enter and remove unwanted liquids (e.g., water) and gases (e.g., nitrogen). When there are at least two fuel cells, the fuel cell represents a fuel stack. In this regard, one or more sensors can be used to monitor selected fuel cells or all fuel cells. In some instances, the end cells of the fuel stack are monitored by one or more sensors.

[0054] In step 604, after the first purge, a second parameter of one or more fuel cells is obtained. Similar to the first parameter, the controller can obtain data related to the second parameter from a sensor. Additionally, the same sensor used to measure / monitor the first parameter can also be used to measure / monitor the second parameter.

[0055] In step 606, the difference between the first parameter and the second parameter is obtained. When there are at least two fuel cells, the difference between the first parameter and the second parameter of each fuel cell.

[0056] In step 608, it is determined whether one or more differences are greater than a threshold difference (or a set of threshold differences). When there are at least two fuel cells, it is determined whether each difference is above or below a predetermined threshold difference. When the difference is below the predetermined threshold difference, method 600 returns to step 602 and determines new first parameters before purging. Additionally, when the predetermined threshold difference is not exceeded, the controller may not implement a new time delay for subsequent purging of the fuel cell. When the difference exceeds the predetermined threshold difference, method 600 proceeds to step 610. When there are at least two fuel cells, the controller may manage each fuel cell independently so that each fuel cell is evaluated and advanced independently in method 600.

[0057] In step 610, a time delay for a second purge is determined based on the difference. The time delay may represent the time at which the controller initiates a second or next purge after the first purge. When there are at least two fuel cells, the time delay may be determined independently for each fuel cell based on an evaluation of the respective first and second parameters.

[0058] For convenience, various examples of aspects of the present disclosure are described below in terms of clauses. These are provided only as examples and do not limit the subject technology, nor the scope of the present disclosure and the claims as understood by those skilled in the art or the general public.

[0059] Clause A: A fuel cell system includes: a fuel cell assembly including an anode exhaust and a fuel cell; a valve configured to discharge a purge gas from the anode exhaust; and a valve controller configured to: obtain a first parameter of the fuel cell before a first purge of the fuel cell with the purge; obtain a second parameter of the fuel cell after the first purge; obtain a difference between the first parameter and the second parameter; and determine a time delay for a second purge after the first purge based on the difference.

[0060] Clause B: A method for adaptively purging a fuel cell includes: obtaining a first parameter of the fuel cell before performing a first purge; obtaining a second parameter of the fuel cell after performing the first purge; obtaining a difference between the first parameter and the second parameter; and determining a time delay for a second purge after the first purge based on the difference.

[0061] One or more of the above clauses may include one or more of the features described below. It should be noted that any of the following clauses may be combined with each other in any combination and placed in their respective independent clauses, such as clause A or B.

[0062] Clause 1: Wherein: the first parameter includes a first output voltage of the fuel cell, and the second parameter includes a second output voltage of the fuel cell.

[0063] Clause 2: wherein: the first parameter includes the first temperature of the fuel cell, and the second parameter includes the second temperature of the fuel cell.

[0064] Clause 3: wherein: the first parameter includes the first current of the fuel cell, and the second parameter includes the second current of the fuel cell.

[0065] Clause 4: wherein: the first parameter includes the first current of the fuel cell, and the second parameter includes the second current of the fuel cell.

[0066] Clause 5: wherein: the first parameter includes the first altitude or the first humidity of the fuel cell, and the second parameters respectively include the second altitude or the second humidity of the fuel cell.

[0067] Clause 6: wherein the valve controller is configured to perform a second purge at a time equal to the time delay.

[0068] Clause 7: wherein the difference is inversely proportional to the time delay.

[0069] Clause 8: wherein the valve controller is configured to set the time delay to zero when the difference is below a threshold difference.

[0070] Clause 9: wherein: obtaining the first parameter includes measuring the first output voltage of the fuel cell, and obtaining the second parameter includes measuring the second output voltage of the fuel cell.

[0071] Clause 10: wherein: obtaining the first parameter includes measuring the first temperature of the fuel cell, and obtaining the second parameter includes measuring the second temperature of the fuel cell.

[0072] Clause 11: wherein: obtaining the first parameter includes measuring the first temperature of the fuel cell, and obtaining the second parameter includes measuring the second temperature of the fuel cell.

[0073] Clause 12: wherein: obtaining the first parameter includes measuring the first current of the fuel cell, and obtaining the second parameter includes measuring the second current of the fuel cell.

[0074] Clause 13: further includes performing a second purge at a purge delay time.

[0075] As used herein, the phrase "at least one of" before a series of items, separated by the terms "and" or "or" any of the items, modifies the entire list rather than each member of the list (i.e., each item). The phrase "at least one of" does not require selection of at least one of each of the listed items; rather, the allowed meanings of the phrase include at least one of any one of the items, and / or at least one of any combination of the items, and / or at least one of each of the items. For example, the phrase "at least one of A, B, and C" or "at least one of A, B, or C" each refers to only A, only B, or only C; any combination of A, B, and C; and / or at least one of each of A, B, and C.

[0076] The predicate words "configured to", "operable to", and "programmed to" do not imply any particular tangible or intangible modification to the subject matter, but are intended to be used interchangeably. In one or more embodiments, a processor configured to monitor and control operations or components may also refer to a processor programmed to monitor and control operations or a processor operable to monitor and control operations. Similarly, a processor configured to execute code may also be understood as a processor programmed to execute code or a processor operable to execute code.

[0077] Phrases such as aspect, the aspect, another aspect, some aspects, one or more aspects, embodiment, the embodiment, another embodiment, some embodiments, one or more embodiments, instance, the instance, another instance, some instances, one or more instances, configuration, the configuration, another configuration, some configurations, one or more configurations, the present subject matter technology, disclosure, the present disclosure, and other variants thereof are for convenience and do not imply that the disclosures related to such phrases are necessary for the present subject matter technology, nor do they imply that these disclosures apply to all configurations of the present subject matter technology. The disclosures related to such phrases may apply to all configurations or may apply to one or more configurations. The disclosures related to such phrases may provide one or more instances. Phrases such as aspect or some aspects may refer to one or more aspects and vice versa, and the same applies to the other aforementioned phrases.

[0078] As used herein, the term "exemplary" means "serving as an example, instance, or illustration." Any instance described herein as "exemplary" or "example" is not necessarily to be construed as preferred or better than other instances. Further, where terms such as "include," "have," etc. are used in the disclosure or claims, such terms are intended to be inclusive in a manner similar to the term "comprise" as it is interpreted when used as a transitional word in a claim as "comprise."

Claims

1. A fuel cell system, comprising: A fuel cell assembly, comprising an anode exhaust device and a fuel cell; A valve configured to discharge a purge gas from the anode exhaust device; And A valve controller configured to: Before performing a first purge of the fuel cell with the purge gas, obtain a first parameter of the fuel cell; After the first purge, obtain a second parameter of the fuel cell; Obtain a difference between the first parameter and the second parameter; And Based on the difference, determine a time delay for a second purge after the first purge.

2. The fuel cell system according to claim 1, wherein: The first parameter includes a first altitude or a first humidity of the fuel cell, and The second parameter respectively includes a second altitude or a second humidity of the fuel cell.

3. The fuel cell system according to claim 1, wherein: The first parameter includes a first temperature of the fuel cell, and The second parameter includes a second temperature of the fuel cell; and Wherein the valve controller is configured to perform the second purge at a time equal to the time delay.

4. The fuel cell system according to claim 1, wherein the difference is inversely proportional to the time delay.

5. The fuel cell system according to claim 4, wherein: The first parameter includes a first current of the fuel cell, and The second parameter includes a second current of the fuel cell.

6. The fuel cell system according to claim 1, wherein: The first parameter includes a first output voltage of the fuel cell, and The second parameter includes a second output voltage of the fuel cell.

7. The fuel cell system according to claim 1, wherein the first parameter includes a first temperature of the fuel cell, and The second parameter includes a second temperature of the fuel cell.

8. The fuel cell system according to claim 1, wherein the valve controller is configured to: The first parameter includes a first temperature of the fuel cell, and The second parameter includes a second temperature of the fuel cell.

9. The fuel cell system according to claim 1, wherein the valve controller is configured to set the time delay to zero when the difference is lower than a threshold difference.

10. A method for adaptively purging a fuel cell, the method comprising: Before performing a first purge, obtain a first parameter of the fuel cell; After performing the first purge, obtain a second parameter of the fuel cell; Based on a difference between the first parameter and the second parameter, determine a purge delay time; And, At the purge delay time, perform a second purge after the first purge.

11. The method according to claim 10, wherein: Obtaining the first parameter includes measuring a first output voltage of the fuel cell, and; Obtaining the second parameter includes measuring a second output voltage of the fuel cell.

12. The method according to claim 10, wherein: Obtaining the first parameter includes measuring a first temperature of the fuel cell, and Obtaining the second parameter includes measuring the second temperature of the fuel cell.

13. The method according to claim 10, wherein: Obtaining the first parameter includes measuring the first temperature of the fuel cell, and Obtaining the second parameter includes measuring the second temperature of the fuel cell.

14. The method according to claim 10, wherein: Obtaining the first parameter includes measuring the first current of the fuel cell; and, Obtaining the second parameter includes measuring the second current of the fuel cell.

15. The method according to claim 10, wherein: Obtaining the first parameter includes measuring the first humidity of the fuel cell; and, Obtaining the second parameter includes measuring the second humidity of the fuel cell.

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