Air supply system for fuel cell and control method thereof

Abstract

An air supply system for a fuel cell comprises: a fuel cell stack in which a plurality of unit cells are stacked and electricity is generated by chemical reactions; an air channel which supplies introduced air containing oxygen to the fuel cell stack and transfers air exhausted from the fuel cell stack to the outside of the air supply system; and a gas adsorption unit arranged on the air channel, which is located near the outlet of the fuel cell stack and is configured to adsorb oxygen contained in the air introduced into the air channel.

Description

Technical Field

[0001] The invention relates to an air supply system for a fuel cell and a control method thereof. Background Art

[0002] The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

[0003] A fuel cell is a power generation device that directly converts chemical energy generated by the oxidation of fuel into electrical energy. A fuel cell is basically the same as a chemical battery in that it uses oxidation and reduction reactions, but a fuel cell differs from a chemical battery in that the latter is a closed reaction system in which reactants are continuously supplied and reaction products are continuously removed. In recent years, fuel cells have been put into practical use, and since the reaction product of such a fuel cell is pure water, research has been actively conducted to use such a fuel cell as an energy source for environmentally friendly vehicles.

[0004] The fuel cell includes a fuel cell stack that generates electric energy through chemical reactions, an air supply device that supplies air to an air pole of the fuel cell stack, and a hydrogen supply device that supplies hydrogen to a hydrogen pole of the fuel cell stack.

[0005] In other words, air containing oxygen is supplied to the air pole (cathode) of the fuel cell stack, and hydrogen is supplied to the hydrogen pole (anode) of the fuel cell stack.

[0006] When the operation of the fuel cell stack is stopped, the supply of air to the fuel cell stack is stopped. In this state, hydrogen remaining in the hydrogen supply line is introduced into the air electrode due to the cross-over phenomenon, and the introduced hydrogen and the remaining oxygen react on the air electrode. Due to this reaction, negative pressure is generated in the fuel cell stack, resulting in the problem of introducing external air into the fuel cell stack.

[0007] Figure 1 is a graph showing a potential curve when oxygen is introduced into a hydrogen electrode in the prior art, and Figure 2 Graphs showing IV performance curves in a case where the electrode is corroded and a case where the electrode is not corroded.

[0008] Reference Figure 1 and Figure 2 When the fuel cell system stops generating electricity, it is necessary to prevent air from being supplied to the fuel cell stack. However, it is difficult to completely prevent air from being introduced into the fuel cell stack.

[0009] The air introduced into the air pole of the fuel cell stack permeates through the hydrogen pole. In this case, the oxygen in the air is the main cause of corrosion of the fuel cell stack electrodes.

[0010] We have found that when the power generation operation of the fuel cell stack is resumed after a temporary stop, and when hydrogen is supplied to the hydrogen electrode, a hydrogen / oxygen interface is formed between region A and region B, thereby forming a high potential region. Due to the presence of this high potential region, corrosion easily occurs on the electrode of the fuel cell stack.

[0011] When the electrodes in a fuel cell stack corrode, such as from Figure 2 It can be seen from the graph that each unit cell in the fuel cell stack provides a reduced voltage for the same current. That is, the power generation performance of the fuel cell stack is reduced.

[0012] The foregoing content is only intended to help understand the background of the present invention, and is not intended to indicate that the present invention falls within the scope of the prior art known to those skilled in the art. Summary of the invention

[0013] The present invention provides an air supply system for a fuel cell that is capable of suppressing or preventing the introduction of oxygen into a fuel cell stack when the fuel cell stack stops generating power.

[0014] In one form of the present invention, an air supply system for a fuel cell may include: a fuel cell stack in which a plurality of unit cells are stacked on each other and generate electricity through chemical reactions; an air channel that supplies introduced air containing oxygen to an inlet of the fuel cell stack and transfers air exhausted from an outlet of the fuel cell stack to the outside of the air supply system; and a gas adsorption unit that is arranged on the air channel, located near the outlet of the fuel cell stack, and adsorbs oxygen contained in the air introduced into the air channel.

[0015] The gas adsorption unit may include diatomaceous earth powder containing a metal and a catalyst, so that oxygen in the air flowing through the air passage is adsorbed in the gas adsorption unit.

[0016] The system may also include: a voltage source configured to apply a voltage to the gas adsorption unit to react oxygen adsorbed in the gas adsorption unit with the fuel; and a power controller configured to control the voltage source to apply or not apply a voltage to the gas adsorption unit based on an operating state of the fuel cell stack.

[0017] The voltage source may be a portion of a plurality of unit cells included in a fuel cell stack.

[0018] The system may further include: a switch provided between the voltage source and the gas adsorption unit. The power controller is configured to control the switch to be turned on so that the voltage is applied to the gas adsorption unit through the switch when the power generation operation of the fuel cell stack is restored.

[0019] The system may also include: a fuel return channel configured to return fuel discharged from an outlet of the fuel cell stack to an inlet of the fuel cell stack; a purge channel connecting the fuel return channel and the air channel, wherein the purge channel is connected to the fuel return channel at a position close to the outlet of the fuel cell stack; a purge valve disposed on the purge channel and configured to adjust the flow rate of fuel flowing through the purge channel when air in the fuel return channel is discharged into the air channel through the purge channel; and a purge controller configured to control the purge valve to open when the power generation operation of the fuel cell stack is resumed.

[0020] In another form, the system may further include: a fuel return channel configured to return fuel discharged from an outlet of the fuel cell stack to an inlet of the fuel cell stack; a purge channel connecting the fuel return channel and the air channel, wherein the purge channel is connected to the fuel return channel at a position close to the outlet of the fuel cell stack; and a purge valve disposed on the purge channel and configured to regulate the flow rate of fuel flowing through the purge channel when air in the fuel return channel is discharged into the air channel through the purge channel, wherein when the purge valve is controlled to open, the power controller can control the voltage source to apply voltage to the gas adsorption unit.

[0021] The system may further include: a shutoff valve disposed on the air passage near an outlet of the fuel cell stack and downstream of the gas adsorption unit, wherein the shutoff valve is configured to block air from flowing through the air passage when power generation operation of the fuel cell stack is stopped.

[0022] In another form of the present invention, a method for controlling an air supply system for a fuel cell includes: determining whether to restore the power generation operation of the fuel cell stack; when the power generation operation of the fuel cell stack is restored, controlling a voltage source to apply voltage to a gas adsorption unit; and supplying air to the fuel cell stack through the air channel while applying voltage to the gas adsorption unit.

[0023] The method may further include, after supplying air to the fuel cell stack, purifying a fuel return channel by discharging fuel in the fuel return channel into the air channel, wherein the fuel discharged from the outlet of the fuel cell stack returns to the inlet of the fuel cell stack through the fuel return channel.

[0024] The method may further include stopping applying the voltage from the voltage source to the gas adsorption unit after purging the fuel return passage.

[0025] The method may further include: determining whether the power generation operation of the fuel cell stack is stopped before determining whether to resume the power generation operation of the fuel cell stack; and stopping applying the voltage from the voltage source to the gas adsorption unit when the power generation operation of the fuel cell stack is stopped.

[0026] In the step of controlling the application of the voltage to the gas adsorption unit, a part of a plurality of unit cells included in the fuel cell stack may be connected to the gas adsorption unit.

[0027] When the power generation operation of the fuel cell stack is stopped, the system and method of the present invention can prevent oxygen from being introduced into the fuel cell stack. Therefore, the system and method can prevent corrosion of the fuel cell electrodes when the power generation operation of the fuel cell stack is resumed, thereby improving the durability of the fuel cell stack.

[0028] In addition, the system and method of the present invention are configured to enable the hydrogen exhausted from the fuel return passage to react with oxygen when the power generation operation of the fuel cell stack is restored. Therefore, when the power generation operation of the fuel cell stack is restored, the concentration of hydrogen in the air exhausted to the outside can be reduced.

[0029] Further areas of applicability will become apparent from the description provided herein.It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order that the present invention may be better understood, various forms of the present invention will now be described by way of example with reference to the accompanying drawings, in which:

[0031] Figure 1 is a diagram showing a potential curve when oxygen is introduced into a fuel electrode in the prior art;

[0032] Figure 2 Graphs showing IV performance curves when the electrode is corroded and when the electrode is not corroded;

[0033] Figure 3 is a schematic diagram showing the construction of a fuel cell air supply system of one form of the present invention;

[0034] Figure 4 is a view showing the overall configuration of a gas adsorption unit used in one form of the present invention;

[0035] Figure 5 is a flow chart illustrating a method for controlling a fuel cell air supply system according to one form of the present invention; and

[0036] Figure 6 is a graph showing the performance difference between a fuel cell to which a fuel cell air supply system of one form of the present invention is applied and a typical fuel cell of a comparative example.

[0037] The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. DETAILED DESCRIPTION

[0038] The following description is merely exemplary in nature and is not intended to limit the invention, its application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate the same or corresponding components and features.

[0039] The specific structural or functional description of the form of the present invention is provided for illustrative purposes only. The present invention can be implemented in various forms and should not be construed as being limited to the forms described in the present invention.

[0040] According to the concept of the present invention, various forms are possible, and only some forms will be shown in the drawings and described in detail in the following description. Therefore, the present invention should be interpreted as covering not only specific forms, but also all modifications, equivalent forms and substitutes falling within the concept and technical spirit of the present invention.

[0041] The terms "first", "second", etc. used in the specification may be used to distinguish one element from another element, and unless otherwise specified, the order or priority of these elements is not limited by these terms. Therefore, without departing from the scope of the present invention, only for the purpose of distinguishing one element from another element, a first element of one form may be referred to as a second element of another form, and similarly, a second element of one form may be referred to as a first element of another form.

[0042] It should be understood that when an element is referred to as being "connected" or "coupled" to another element, it may be directly connected or coupled to the other element, or there may be intervening elements between them. Conversely, it should be understood that when an element is referred to as being "directly coupled" or "directly connected" to another element, there are no intervening elements. Other expressions used herein to describe the relationship between elements, for example, "between," "directly between," "adjacent," or "directly adjacent," should be interpreted in the same manner as described above.

[0043] The terms used herein are only used to illustrate specific embodiments and are not intended to limit the present invention. As used herein, the singular forms "a", "an" and "the" are also intended to include plural forms unless the context clearly indicates. It is further understood that when "including", "comprising" or "having" is used in this specification, it refers to the presence of stated features, regions, integers, steps, operations, elements and / or parts, but does not exclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, parts and / or combinations thereof.

[0044] In addition, unless defined in a different manner, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by those skilled in the art to which the present invention belongs. It will be further understood that terms such as those defined in commonly used dictionaries should be interpreted as having the same meaning as the contextual meaning in the relevant field and the present invention. Unless clearly defined in this application, these terms should not be interpreted as having an ideal or overly formal meaning.

[0045] Hereinafter, exemplary forms of the present invention will be described with reference to the accompanying drawings, in which the same reference numerals represent the same elements.

[0046] Figure 3 is a schematic diagram showing the configuration of a fuel cell air supply system in one form of the present invention, and Figure 4 : is a schematic diagram showing the configuration of a gas adsorption unit used in one form of the present invention.

[0047] Reference Figure 3 and Figure 4 The fuel cell air supply system includes: a fuel cell stack 10, which includes a plurality of unit cells stacked on each other and generating electrical energy through chemical reactions; an air channel 20, configured to supply air containing oxygen to an inlet 11 of the fuel cell stack, and to discharge air exhausted from an outlet 12 of the fuel cell stack 10 to the outside; and a gas adsorption unit 30, which is arranged on the air channel 20, located near the outlet 12 of the fuel cell stack 10, and configured to absorb oxygen in the air introduced into the air channel 20.

[0048] The fuel cell stack 10 receives hydrogen gas and air containing oxygen as fuel, and generates electric energy through chemical reactions at an anode (also referred to as a hydrogen electrode or a fuel electrode) and a cathode (also referred to as an oxygen electrode or an air electrode). In the fuel cell stack 10, hydrogen gas and oxygen gas react with each other, thereby generating water as a byproduct.

[0049] The fuel cell stack 10 is a cell stack of a plurality of unit cells. Fuel (hydrogen) and air (oxygen) are introduced into each unit cell to generate electricity. The unit cells are connected in series so that the fuel cell stack 10 can output a rated voltage.

[0050] The air passage 20 is used to supply external air to the fuel cell stack 10 and to discharge used air discharged from the fuel cell stack 10 to the outside. A blower or a compressor 21 is located at an input port of the air passage 20 .

[0051] When the fuel cell stack 10 generates electric energy, the blower or compressor 21 operates so that air may be introduced into the fuel cell stack 10 through the air passage 20 , and then used air is exhausted from the fuel cell stack 10 to the outside through the air passage 20 .

[0052] However, when the power generation operation of the fuel cell stack 10 is stopped, the introduction of air into the air passage 20 is stopped. At this time, the air flows back into the fuel cell stack 10 through the outlet 12.

[0053] A humidifier 22 for humidifying air to be introduced into the fuel cell stack 10 is located near the input port of the air channel 20. The humidifier 22 is connected to the output port of the air channel 20, which is connected to the outlet 12 of the fuel cell stack 10. The humidifier 22 may be used to transfer moisture contained in the air exhausted from the output port of the air channel 20 to the inlet 11 of the fuel cell stack 10.

[0054] The gas adsorption unit 30 is disposed near the outlet of the air passage 20. In other words, the gas adsorption unit 30 is disposed on the air passage 20 and is located near the outlet 12 of the fuel cell stack 10.

[0055] In a state where the power generation operation of the fuel cell stack 10 is not performed, the gas adsorption unit 30 adsorbs and removes oxygen contained in the air exhausted from the output port of the air passage 20 .

[0056] Therefore, when the power generation operation of the fuel cell stack 10 is stopped, oxygen is blocked or prevented from being introduced into the fuel cell stack 10, and since corrosion of the electrodes is prevented when the power generation operation of the fuel cell stack 10 is resumed, the durability of the fuel cell stack 10 can be improved.

[0057] In one form, the gas adsorption unit 30 includes diatomaceous earth powder containing metal and catalyst. The gas adsorption unit 30 adsorbs oxygen contained in the air flowing through the air passage 20.

[0058] The diatomaceous earth powder may include iron powder, pro-oxidant (catalyst) particles, and fillers. The gas adsorption unit 30 is made of coated diatomaceous earth nanoparticles. The gas adsorption unit 30 adsorbs oxygen contained in the air flowing through the air passage 20.

[0059] When voltage is applied to the gas adsorption unit 30, hydrogen and oxygen react with each other to generate water. Hydrogen in the air flowing through the air passage 20 reacts with oxygen adsorbed on the gas adsorption unit 30. Therefore, the amount of hydrogen exhausted through the air passage 20 can be reduced.

[0060] The air supply system also includes: a voltage source 40, which applies voltage to the gas adsorption unit 30 so that the oxygen adsorbed on the gas adsorption unit 30 can react with the fuel (i.e., hydrogen); a power controller 80, which controls the application of voltage from the voltage source to the gas adsorption unit 30 based on the working state of the fuel cell stack 10.

[0061] In another form, when the power generation operation of the fuel cell stack 10 is restored, the power controller 80 controls the voltage source 40 to apply voltage to the gas adsorption unit 30. Therefore, the oxygen adsorbed in the gas adsorption unit 30 reacts with the hydrogen exhausted from the fuel return channel into the air channel 20, thereby removing the hydrogen from the air to be discharged to the outside.

[0062] In some forms, when the power generation operation of the fuel cell stack 10 stops, the power controller 80 controls the voltage source 40 to stop applying the voltage to the gas adsorption unit 30. Therefore, oxygen can be adsorbed in the gas adsorption unit 30.

[0063] In some forms, the application of voltage from the voltage source 40 to the gas adsorption unit 30 may be stopped while the power generation operation of the fuel cell stack is continued. In a state where the power generation operation of the fuel cell stack is stopped, the voltage source 40 is controlled to apply voltage to the gas adsorption unit 30 for a predetermined period of time to remove oxygen adsorbed in the gas adsorption device 30.

[0064] The voltage source 40 may be implemented by a portion of the plurality of unit cells included in the fuel cell stack 10. In other words, the voltage source 40 may be implemented by a discrete device (eg, a separate battery) or a portion of the plurality of unit cells included in the fuel cell stack 10.

[0065] The air supply system further includes a switch 41 provided between the voltage source 40 and the gas adsorption unit 30. The power controller 80 controls the switch 41 to be turned on so that a voltage can be applied to the gas adsorption unit 30 through the switch when the power generation operation of the fuel cell stack 10 is stopped and then resumed.

[0066] The power controller 80 may control the switch 41 to be turned on so that the voltage source 40 and the gas adsorption unit 30 are connected to each other or control the switch 41 to be turned off so that the voltage source 40 and the gas adsorption unit 30 are disconnected from each other.

[0067] The air supply system further includes a fuel return passage 50 through which the fuel exhausted from the outlet of the fuel cell stack 10 is returned to the inlet of the fuel cell stack 10 .

[0068] In another form, the system may further include a purge valve 61 disposed on the purge passage 60 connecting the fuel return passage 50 and the air passage 20. In some forms, the purge passage 60 is connected to the fuel return passage 50 at a position close to the outlet of the fuel cell stack 10, and the purge valve 61 controls the flow rate of the fuel discharged from the fuel return passage 50 to the air passage 20 through the purge passage 60. In one form, the system may further include a purge controller 70 that controls the purge valve to open when the power generation operation of the fuel cell stack 10 is stopped and then resumed.

[0069] The fuel return passage 50 is a flow path along which hydrogen mixed with impurities such as moisture and nitrogen flows. The fuel return passage 50 is purged periodically so that the hydrogen with impurities in the fuel return passage 50 can be removed periodically.

[0070] The purge controller 70 controls the purge valve to open or close. In this way, the fuel return passage 50 can be purged. The purge controller 70 estimates the hydrogen concentration in the air in the fuel return passage 50 and controls the purge valve to open when the estimated hydrogen concentration is lower than a predetermined lower limit value to purge the fuel return passage 50.

[0071] During the stop of the power generation operation of the fuel cell stack 10, hydrogen is not supplied to the fuel electrode. In this state, a crossover phenomenon occurs between the fuel electrode and the air electrode, so that the impurity concentration increases.

[0072] To this end, when the power generation operation of the fuel cell stack 10 is stopped and then resumed, the purge controller 70 controls the purge valve to be opened so that the fuel return passage 50 can be purged.

[0073] When the purge valve is controlled to be opened, the power controller 80 controls the voltage source 40 to apply a voltage to the gas adsorption unit 30 .

[0074] The purge controller 70 controls the purge valve to open so that the fuel return passage 50 can be purged not only when the power generation operation of the fuel cell stack 10 is stopped and then resumed, but also when the power generation operation of the fuel cell stack 10 is continued.

[0075] When the purge controller 70 controls the purge valve to open, the power controller 80 controls the voltage source 40 to apply voltage to the gas adsorption unit 30 so that the hydrogen exhausted from the fuel return channel 50 into the air channel 20 can react with the oxygen adsorbed on the gas adsorption unit 30 .

[0076] The system may further include shutoff valves 23 and 24 disposed on the air passage 20 downstream of the gas adsorption unit 30 and configured to block air from flowing through the air passage 20 when the power generation operation of the fuel cell stack 10 is stopped.

[0077] In one form, the shutoff valves 23 and 24 are arranged on the air passage 20 and are located near the outlet 12 of the fuel cell stack 10. The shutoff valves 23 and 24 prevent air from flowing through the air passage during a period when the power generation operation of the fuel cell stack 10 is stopped.

[0078] However, even when the shutoff valves 23 and 24 are closed, if the power generation operation of the fuel cell stack 10 is stopped for a long time, air may be introduced into the air passage 20. The gas adsorption unit 30 arranged on the air passage 20 is located near the outlet 12 of the fuel cell stack 10 and downstream of the shutoff valves 23 and 24.

[0079] In addition, other shutoff valves 23 and 24 may be arranged on the air passage 20 and located near the inlet 11 of the fuel cell stack 10 .

[0080] In one form of the present invention, the purification controller 70 and the power controller 80 may be implemented by: a non-volatile memory (not shown) configured to store data associated with an algorithm for controlling the operation of various components of the vehicle or data associated with software instructions for executing the algorithm; a processor (not shown) configured to perform the operations described below using the data stored in the non-volatile memory. The memory and the processor may be implemented with separate chips, respectively. The memory and the processor may be implemented with an integrated chip. The processor may be implemented with a processor array.

[0081] Figure 5 is a flow chart illustrating a method of controlling such a fuel cell air supply system according to one form of the present invention.

[0082] Reference Figure 5 The method for controlling the fuel cell air supply system includes: step S300, determining whether to restore the power generation operation of the fuel cell stack 10; step S400, when it is determined that the power generation operation of the fuel cell stack 10 is restored, applying voltage to the gas adsorption unit 30; and step S500, supplying air to the air channel 20 connected to the fuel cell stack 10 while applying voltage to the gas adsorption unit 30.

[0083] Before step S300 , the method may further include: step S100 , determining whether the power generation operation of the fuel cell stack 10 is stopped; and step S200 , when it is determined that the power generation operation of the fuel cell stack 10 is stopped, stopping the application of voltage to the gas adsorption unit 30 .

[0084] When it is determined that the power generation operation of the fuel cell stack 10 is stopped, the switch 41 is turned off so that voltage cannot be applied to the gas adsorption unit 30 , and in this case, oxygen contained in the air flowing through the air passage 20 can be adsorbed on the gas adsorption unit 30 .

[0085] When the power generation operation of the fuel cell stack 10 is resumed after being stopped, a voltage may be applied from the voltage source 40 to the gas adsorption unit 30 .

[0086] In step S500 , air is supplied to the air passage 20 , and a voltage is continuously applied to the gas adsorption unit 30 , so that oxygen adsorbed on the gas adsorption unit 30 may be removed.

[0087] After step S500 of supplying air, the method may further include step S600: purifying the fuel return channel 50 , through which the fuel discharged from the outlet of the fuel cell stack 10 returns to the inlet of the fuel cell stack 10 , so that the fuel in the fuel reflux channel 50 is discharged into the air channel 20 .

[0088] While air is supplied to the air passage 20, the fuel in the fuel return passage 50 is discharged into the air passage 20. Therefore, the fuel in the fuel return passage 50 is diluted by the air before being discharged to the outside.

[0089] In the air supplying step S500, since the gas adsorption unit 30 is in a state where a voltage is applied, the exhausted fuel (hydrogen) reacts with oxygen adsorbed on the gas adsorption unit 30. Therefore, the concentration of hydrogen is reduced before the air is discharged to the outside.

[0090] After step S600 in which the fuel is discharged into the air passage 20 , when the fuel is completely discharged from the fuel return passage, the method may further include step S700 of stopping the application of the voltage from the voltage source 40 to the gas adsorption unit 30 .

[0091] In other words, when the purification is completed and thus hydrogen does not exist in the air passage 20, the switch 41 is turned off, so that the application of voltage from the voltage source 40 to the gas adsorption unit 30 can be stopped. Through this process, power consumption can be reduced.

[0092] In addition, when it is desired to stop the power generation operation of the fuel cell stack 10, the switch 41 is turned on so that the voltage is applied to the gas adsorption unit 30 from the voltage source 40 again. In this way, the oxygen adsorbed on the gas adsorption unit 30 can be removed before stopping the power generation operation of the fuel cell stack 10.

[0093] In step S400 of applying voltage from voltage source 40 to gas adsorption unit 30, a portion of a plurality of unit cells included in fuel cell stack 10 is connected to gas adsorption unit 30. In this case, electric energy generated by fuel cell stack 10 is used to apply voltage to the gas adsorption unit without using an additional power source.

[0094] Figure 6 is a graph showing the performance difference between a fuel cell to which a fuel cell air supply system of one form of the present invention is applied and a typical fuel cell of a comparative example.

[0095] In this graph, each curve represents an average voltage of each unit cell of a plurality of unit cells in a corresponding fuel cell when it is assumed that each fuel cell supplies the same current.

[0096] Reference Figure 6 When a fuel cell air supply system in one form of the present invention is used to inhibit or prevent corrosion of fuel cell electrodes, the performance degradation of the fuel cell of the present invention is slower than that of a typical fuel cell of a comparative example.

[0097] Although only exemplary forms have been described, those skilled in the art will appreciate that various modifications and changes can be made thereto without departing from the scope and spirit of the invention.

Claims

1. An air supply system for a fuel cell, the air supply system comprising: A fuel cell stack including a plurality of unit cells configured to generate electrical energy through a chemical reaction; an air passage configured to supply air containing oxygen to an inlet of the fuel cell stack and to transfer air exhausted from an outlet of the fuel cell stack to the outside of the air supply system; as well as a gas adsorption unit arranged on the air passage, located near an outlet of the fuel cell stack, and configured to adsorb oxygen contained in the air introduced into the air passage; A voltage source is configured to apply a voltage to the gas adsorption unit so that the oxygen adsorbed in the gas adsorption unit reacts with the fuel.

2. The air supply system according to claim 1, wherein: The gas adsorption unit includes diatomaceous earth powder containing metal and catalyst, and is configured to adsorb oxygen in the air flowing through the air passage.

3. The air supply system according to claim 1, further comprising: A power controller is configured to control the voltage source to selectively apply voltage to the gas adsorption unit based on an operating state of the fuel cell stack.

4. The air supply system according to claim 3, wherein: The voltage source is implemented by a portion of the plurality of unit cells included in the fuel cell stack.

5. The air supply system according to claim 3, further comprising: A switch is provided between the voltage source and the gas adsorption unit, The power supply controller is configured to control the switch to be turned on so that a voltage is applied to the gas adsorption unit through the switch when the power generation operation of the fuel cell stack is stopped and then resumed.

6. The air supply system according to claim 3, further comprising: a fuel return channel configured to return the fuel discharged from the outlet of the fuel cell stack to the inlet of the fuel cell stack; a purge passage connecting the fuel return passage and the air passage, wherein the purge passage is connected to the fuel return passage at a position close to an outlet of the fuel cell stack; as well as a purge valve disposed on the purge passage and configured to adjust a flow rate of fuel flowing through the purge passage when air in the fuel return passage is discharged into the air passage through the purge passage, Wherein, the power controller is configured to control the voltage source to apply voltage to the gas adsorption unit when the purge valve is opened.

7. The air supply system according to claim 1, further comprising: a fuel return passage configured to return fuel exhausted from an outlet of the fuel cell stack to an inlet of the fuel cell stack; a purge passage configured to connect the fuel return passage and the air passage, wherein the purge passage is connected to the fuel return passage at a position close to an outlet of the fuel cell stack; a purge valve disposed on the purge passage and configured to adjust a flow rate of the fuel flowing through the purge passage when the fuel in the fuel return passage is discharged into the air passage through the purge passage; and A purge controller is configured to control the purge valve to open when the power generation operation of the fuel cell stack is stopped and then resumed.

8. The air supply system according to claim 1, further comprising: A shutoff valve is arranged on the air passage, which is located near the outlet of the fuel cell stack and downstream of the gas adsorption unit, wherein the shutoff valve is configured to prevent air from flowing through the air passage when the power generation operation of the fuel cell stack is stopped.

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