Hydrogen generating apparatus and fuel cell power generation system controlling amount of hydrogen generation

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Patent Application Publication Sep. 4, 2008 Sheet 4 of 17 US 2008/0213642 A1

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US 2008/0213642 A1 Sep. 4, 2008

HYDROGEN GENERATINGAPPARATUS AND capacity of power, it is necessary that the fuel cell have a large FUEL CELL POWER GENERATION SYSTEM capacity and perform high performance while it is Small. CONTROLLING AMOUNT OF HYDROGEN 0012. In order to meet the above needs, methanol or for GENERATION mic acid, permitted to be brought into an airplane by Interna tional Civil Aviation Organization (ICAO), is used for fuel

CROSS-REFERENCE TO RELATED reforming, or methanol, ethanol, or formic acid is directly APPLICATIONS used as a fuel for the fuel cell.

0013 However, the former case requires a high reforming 0001. This application is a continuation-in-part of U.S. temperature, has a complicated system, consumes driving patent application Ser. No. 1 1/812,656, filed on Jun. 20, 2007. power, and contains impurities (e.g., CO and CO) in addition And this application claims the benefit of Korean Patent to pure hydrogen. The latter case deteriorates power density Application No. 10-2007-0017343 filed with the Korean due to a low rate of a chemical reaction in the anode and a Intellectual Property Office on Feb. 21, 2007, the disclosure cross-over of hydrocarbon through the membrane. of which is incorporated herein by reference in its entirety.

SUMMARY OF THE INVENTION

BACKGROUND OF THE INVENTION

0014. The present invention provides a hydrogen generat 0002 1. Field of the Invention ing apparatus, a fuel cell power generation system, a method 0003. The present invention relates to a hydrogen gener of controlling the quantity of hydrogen generation, and a ating apparatus, more particularly to a hydrogen generating recorded medium recorded with a program performing the apparatus that can control the amount of generation of hydro method that can generate pure hydrogen at room temperature gen Supplied to a fuel cell. through an electrochemical reaction. 0004 2. Background Art 0015 The present invention also provides a hydrogen gen erating apparatus, a fuel cell power generation system, a 0005. A fuel cell refers to an energy conversion apparatus method of controlling the quantity of hydrogen generation, that directly converts chemical energy of a fuel (hydrogen, and a recorded medium recorded with a program performing LNG, LPG, methanol, etc.) and air to electricity and/or heat the method that can control the quantity of hydrogen genera by means of an electrochemical reaction. Unlike a conven tion without a separate BOP (Balance of Plant) unit while tional power generation technology that requires fuel com maintaining a simple structure.

bustion, steam generation, or a turbine orpower generator, the 0016. The present invention also provides a hydrogengen fuel cell technology needs no combustion process or driving erating apparatus, a fuel cell power generation system, a device, thereby boosting energy efficiency and curbing envi method of controlling the quantity of hydrogen generation, ronmental problems. and a recorded medium recorded with a program performing 0006 FIG. 1 illustrates an operational architecture of a the method that are economical and eco-friendly. fuel cell. 0017. The present invention also provides a hydrogen gen 0007 Referring to FIG.1, a fuel cell 100 is composedofan erating apparatus, a fuel cell power generation system, a anode as a fuel pole 110 and a cathode as an air pole 130. The method of controlling the quantity of hydrogen generation, fuel pole 110 is provided with hydrogen molecules (H), and and a recorded medium recorded with a program performing decomposes them into hydrogen ions (H) and electrons (e). the method that can control the quantity of hydrogen genera The hydrogen ion (H) moves toward the air pole 130 via a tion by use of On/Off time and/or On/Off frequency of a membrane 120, which is an electrolyte layer. The electron switch.

moves through an external circuit 140 to generate an electric 0018 Moreover, the present invention provides a hydro current. In the air pole 130, the hydrogen ions and the elec gen generating apparatus, a fuel cell power generation sys trons are combined with oxygen molecules in the atmosphere, tem, a method of controlling the quantity of hydrogen gen generating water molecules. The following chemical formu eration, and a recorded medium recorded with a program las represent the above chemical reactions occurring in the performing the method that can prevent waste or risk of fuel cell 100. leaking Surplus hydrogen in the air simply by turning on the Fuel pole 110: H, P2H'+2e. Switch and reduce the noise and power consumption by not using a gas pump or a liquid pump.

Air pole 130: 2O+2H'+2e PHO 0019 Moreover, the present invention provides a hydro Overall reaction: H2+/3O2 >H.0 CHEMICAL FORMUL.A. 1 gen generating apparatus that can control the amount of gen eration by use of feedback control according to the demand 0008. In short, the fuel cell 100 functions as a battery by from a load connected to the fuel cell. Supplying the electric current, generated due to the flowing of 0020. An aspect of the present invention features a hydro the decomposed electrons, to the external circuit 140. Such a gen generating apparatus that is capable of controlling the fuel cell 100 hardly emits an atmospheric pollutant such as amount of hydrogen generation.

Sox and NOx and makes little noise and vibration. 0021. The hydrogen generating apparatus in accordance 0009 Meanwhile, in order to produce electrons in the fuel with an embodiment of the present invention includes an pole 110, the fuel cell 100 necessitates a hydrogen generating electrolyzer, which is filled with an aqueous electrolyte solu apparatus that can change a common fuel to hydrogen gas. tion containing hydrogen ions, a first electrode, which is 0010. A hydrogen storage tank, generally known as a accommodated in the electrolyzer, is submerged in the aque hydrogen generating apparatus, however, occupies a large ous electrolyte Solution, and generates electrons, a second space and should be kept with care. electrode, which is accommodated in the electrolyzer, is sub 0011 Moreover, as a portable electronic device, such as a merged in the aqueous electrolyte solution, and receives the mobile phone and a notebook computer, requires a large electrons to generate hydrogen, a Switch, which is located

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between the first electrode and the second electrode, a flow switch. The metal forming the first electrode can have a rate meter, which measures an amount of hydrogen genera higher ionization tendency than a metal forming the second tion in the second electrode, and a switch controller, which electrode.

receives a set value, compares the amount of hydrogen gen 0029. The switch controller can generate and output a eration measured by the flow rate meter with the set value, and Switch control signal turning the Switch on and off, and the controls an on/off status of the Switch. switch controller can determine an on/off ratio of the switch 0022. The switch controller can be inputted with the set within one cycle by varying a duty ratio of the switch control value directly from a user through an input device. The hydro signal. The Switch controller can control a fluctuation in the gen generating apparatus can be coupled to a fuel cell and amount of hydrogen generation by varying an on/off fre Supplies hydrogen, and the Switch controller can be inputted with the set value in accordance with an amount of hydrogen quency of the Switch control signal. The Switch controller can generation that is required by the fuel cell. compare the demanded power with the output, and can reduce 0023 The metal forming the first electrode can have a the duty ratio if the output is greater than the demanded higher ionization tendency than a metal forming the second power, increase the duty ratio if the output is smaller than the electrode. demanded power, and maintain the duty ratio if the output is 0024. The flow rate meter can measure the amount of equal to the demanded power.

hydrogen generation in units of flowrate. The Switch control 0030 The fuel cell power generation system in accor ler can generate and output a Switch control signal turning the dance with an embodiment of the present invention further switch on and off, and the switch controller can determine an comprises a rechargeable battery, being coupled between the on/off ratio of the switch within one cycle by varying a duty fuel cell and the load, being charged by the electric energy ratio of the Switch control signal. from the fuel cell, and providing the charged electric energy 0025. The switch controller can control a fluctuation in the when the load needs.

amount of hydrogen generation by varying an on/off fre 0031. The hydrogen generating apparatus can include an quency of the Switch control signal. The Switch controller can electrolyzer, which is filled with an aqueous electrolyte solu compare the set value with the measured amount of hydrogen tion containing hydrogen ions, a first electrode, which is generation, and can increase the duty ratio if the amount of accommodated in the electrolyzer, Submerged in the aqueous hydrogen generation is Smaller than the set value, reduce the electrolyte Solution, and generating electrons, a second elec duty ratio if the amount of hydrogen generation is greater than the set value, and maintain the duty ratio if the amount of trode, which is accommodated in the electrolyzer, Submerged hydrogen generation is equal to the set value. The set value in the aqueous electrolyte Solution, receiving the electrons to includes an upper limit and a lower limit, and the Switch generate hydrogen, a Switch, which is located between the controller can compare the set value with the measured first electrode and the second electrode, a Switch controller, amount of hydrogen generation, and can increase the duty which measures present Voltage of the rechargeable battery, ratio if the amount of hydrogen generation is Smaller than the compares a fully-charged Voltage with the present Voltage, lower limit, reduce the duty ratio if the amount of hydrogen and controlling an on/off status of the switch. The metal generation is greater than the upper limit, and maintain the forming the first electrode can have a higher ionization ten duty ratio if the amount of hydrogen generation is between the dency than a metal forming the second electrode. lower limit and the upper limit. 0032. The switch controller generates and outputs a switch 0026. Another aspect of the present invention features a control signal turning the Switch on and off, and the Switch fuel cell power generation system including a hydrogen gen controller determines an on/off ratio of the switch within one erating apparatus that is capable of controlling the amount of cycle by varying a duty ratio of the Switch control signal. And hydrogen generation. the switch controller controls a fluctuation in the amount of 0027. The fuel cell power generation system in accor hydrogen generation by varying an on/off frequency of the dance with an embodiment of the present invention has a Switch control signal.

hydrogen generating apparatus, which controls an amount of 0033. The switch controller compares the present voltage hydrogen generation by controlling an on/off status of a with the fully-charged Voltage, and increases the duty ratio if switch connected between electrodes, a fuel cell, which is the present Voltage is Smaller than the fully-charged Voltage, Supplied with hydrogen generated by the hydrogen generat and minimizes the duty ratio if the present Voltage is equal to ing apparatus and produces a direct current by converting or greater than the fully-charged Voltage. chemical energy of the hydrogen to electrical energy, and a 0034. The meter can be an output meter that measures an load, which is provided the electric energy and performing a output of the fuel cell in units of watt (W), volt (V), ampere predetermined operation. (A), ohm (S2) and a combination thereof. The switch control 0028. The hydrogen generating apparatus can include an ler can control a fluctuation in the output of the fuel cell by electrolyzer, which is filled with an aqueous electrolyte solu varying an on/off frequency of the Switch control signal. The tion containing hydrogen ions, a first electrode, which is switch controller can compare the set value with the measured accommodated in the electrolyzer, is submerged in the aque output of the fuel cell, and can increase the duty ratio if the ous electrolyte solution, and generates electrons, a second output of the fuel cell is smaller than the set value, reduce the electrode, which is accommodated in the electrolyzer, is sub duty ratio if the output of the fuel cell is greater than the set merged in the aqueous electrolyte solution, and receives the value, and maintain the duty ratio if the output of the fuel cell electrons to generate hydrogen, a Switch, which is located is equal to the set value. The set value can include an upper between the first electrode and the second electrode, a Switch limit and a lower limit, and the Switch controller can compare controller, which received a demanded power from the load, the set value with the measured output of the fuel cell, and can measuring an output of the fuel cell, compares the demanded increase the duty ratio if the output of the fuel cell is smaller power with the output, and controls an on/off status of the than the lower limit, reduce the duty ratio if the output of the

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fuel cell is greater than the upper limit, and maintain the duty fully-charged Voltage, in which the Switch control signal con ratio if the output of the fuel cell is between the lower limit trols the on/off status of the switch within one cycle in accor and the upper limit. dance with the duty ratio.

0035 Another aspect of the present invention features a method of controlling an amount of hydrogen generation in a BRIEF DESCRIPTION OF THE DRAWINGS hydrogen generating apparatus controlling an amount of hydrogen generation by controlling an on/off status of a 0040. These and other features, aspects and advantages of switch located between electrodes. the present invention will become better understood with 0036. The method of controlling an amount of hydrogen regard to the following description, appended claims and accompanying drawings where:

generation in accordance with an embodiment of the present invention includes the steps of being inputted with a set value; 0041 FIG. 1 illustrates an operational architecture of a comparing a measured amount of hydrogen generation and fuel cell;

the set value; and increasing a duty ratio of a Switch control 0042 FIG. 2 shows a sectional view of a hydrogen gener signal if the amount of hydrogen generation is Smaller than ating apparatus in accordance with an embodiment of the the set value, reducing the duty ratio of the switch control present invention;

signal if the amount of hydrogen generation is greater than the 0043 FIG.3 is a graph showing the power consumption of set value, and maintaining the duty ratio of the Switch control mobile phone.

signal if the amount of hydrogen generation is equal to the set 0044 FIG. 4 is a graph showing how the amount of electric value, in which the switch control signal controls the on/off current between a first electrode and a second electrode and status of the switch within one cycle in accordance with the the amount of generated hydrogen are related in a hydrogen duty ratio. generating apparatus in accordance with an embodiment of 0037. The method of controlling an amount of hydrogen the present invention;

generation in accordance with another embodiment of the 0045 FIG. 5 shows a block diagram of a control unit of a present invention includes the steps of being inputted with an hydrogen generating apparatus in accordance with an upper value and a lower value; comparing a measured amount embodiment of the present invention; of hydrogen generation with the upper value and the lower 0046 FIG. 6 shows a block diagram of a fuel cell power value; and increasing a duty ratio of a Switch control signal if generation system in accordance with another embodiment of the present invention;

the amount of hydrogen generation is Smaller than the lower 0047 FIG. 7 is a block diagram of a fuel cell power gen value, reducing the duty ratio of the Switch control signal if eration system in accordance with another embodiment of the the amount of hydrogen generation is greater than the upper present invention.

value, and maintaining the duty ratio of the Switch control 0048 FIG. 8 shows a graph of the amount of hydrogen signal if the amount of hydrogen generation is between the generation, expressed in units of flow rate, when the Switch is lower value and the upper value, in which the switch control turned on:

signal controls the on/offstatus of the switch within one cycle 0049 FIG.9 shows a first example of the on/off frequency in accordance with the duty ratio. of the Switch of a hydrogen generating apparatus in accor 0038. The method of controlling an amount of hydrogen dance with an embodiment of the present invention; generation in accordance with another embodiment of the 0050 FIG. 10 shows a second example of the on/off fre present invention, which is controlling an amount of hydro quency of the Switch of a hydrogen generating apparatus in gen generation by controlling an on/off status of a Switch accordance with an embodiment of the present invention; located between electrodes, measures an output of the fuel 0051 FIG. 11 shows how the amount of hydrogen genera cell, and receiving a demanded power from the load, com tion is related to time when the on/off frequency of the switch pares the output with the demanded power, and reduces a duty is controlled.

ratio of Switch control signal if the output is greater than the 0.052 FIG. 12 shows a first example of duty ratios of the demanded power, increasing the duty ratio of Switch control Switch of a hydrogen generating apparatus in accordance with signal if the output is Smaller than the demanded power, and an embodiment of the present invention; maintains the duty ratio of Switch control signal if the output 0053 FIG.13 shows a second example of duty ratios of the is equal to the demanded power, in which the Switch control Switch of a hydrogen generating apparatus in accordance with signal controls the on/offstatus of the switch within one cycle an embodiment of the present invention; in accordance with the duty ratio. 0054 FIG. 14 shows how the quantity of hydrogen gen 0039. The method of controlling an amount of hydrogen eration is related to time when the duty ratio of the switch is generation in accordance with another embodiment of the controlled.

present invention, which is controlling an amount of hydro 0055 FIG. 15 shows a flowchart of a method of control gen generation by controlling an on/off status of a Switch ling the quantity of hydrogen generation in a hydrogen gen located between electrodes, measures a present Voltage of the erating apparatus in accordance with an embodiment of the rechargeable battery, compares the present Voltage with a present invention;

fully-charged Voltage, and increasing a duty ratio of Switch 0056 FIG. 16 shows a flowchart of a method of control control signal if the present Voltage is Smaller than the fully ling the quantity of hydrogen generation in a hydrogen gen charged Voltage, and minimizes the duty ratio of Switch con erating apparatus in accordance with another embodiment of trol signal if the present Voltage is equal to or greater than the the present invention; and

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0057 FIG. 17 shows a flowchart of a method of control 0065. A hydrogen generating apparatus 200 includes an ling the quantity of hydrogen generation in a hydrogen gen electrolyzer 210, a first electrode 220, a second electrode 230 erating apparatus in accordance with another embodiment of and a control unit 240. For the convenience of description and the present invention. understanding, it will be presumed below that the first elec trode 220 is composed of magnesium (Mg) and the second

DESCRIPTION OF THE EMBODIMENTS electrode 230 is composed of stainless steel. 0066. The electrolyzer 210 is filled with an aqueous elec 0058 Since there can be a variety of permutations and trolyte solution 215. The aqueous electrolyte solution 215 embodiments of the present invention, certain embodiments contains hydrogen ions, which are used by the hydrogen will be illustrated and described with reference to the accom generating apparatus 200 to generate hydrogen gas. panying drawings. This, however, is by no means to restrict 0067 Examples of the electrolyte for the aqueous electro the present invention to certain embodiments, and shall be lyte solution 215 are LiCl, KC1, NaCl, KNO, NaNO, CaCl, construed as including all permutations, equivalents and Sub MgCl, KSO, NaSO, MgSO, AgCl, or the like. stitutes covered by the spirit and scope of the present inven 0068. The electrolyzer 210 accommodates the first elec tion. Throughout the drawings, similar elements are given trode 220 and the second electrode 230, the entirety or por tions of which are submerged in the electrolyte solution 215.

similar reference numerals. Throughout the description of the 0069. The first electrode 220 is an active electrode, where present invention, when describing a certain technology is the magnesium (Mg) is oxidized to magnesium ions (Mg"), determined to evade the point of the present invention, the releasing electrons due to the difference in ionization energies pertinent detailed description will be omitted. of magnesium and water. The released electrons move to the 0059 Terms such as “first and “second can be used in second electrode 230 through a first electric wire 225, the describing various elements, but the above elements shall not control unit 240 and a second electric wire 235. be restricted to the above terms. The above terms are used 0070. The second electrode 230 is an inactive electrode, only to distinguish one element from the other. For instance, where the water molecules receive the electrons moved from the first element can be named the second element, and vice the first electrode 220 and then are decomposed into the Versa, without departing the scope of claims of the present hydrogen molecules.

invention. The term “and/or shall include the combination of 0071. The above chemical reactions can be represented as a plurality of listed items or any of the plurality of listed items. the following chemical formula 2: 0060. When one element is described as being “con First electrode 220: Mg PMg2++2e. nected” or “accessed’ to another element, it shall be con

Strued as being connected or accessed to the other element Second electrode 230:2H,0+2e PH+2(OH) directly but also as possibly having another element in Overall reaction: Mg+ between. On the other hand, if one element is described as 2HOPMg(OH)+H, CHEMICAL FORMULA2 being “directly connected” or “directly accessed to another element, it shall be construed that there is no other element in 0072 The reaction rate and the efficiency of the chemical between. reaction depend on various factors, including the area of the 0061 The terms used in the description are intended to first electrode 220 and/or the second electrode 230, the con describe certain embodiments only, and shall by no means centration of the aqueous electrolyte solution 215, the type of restrict the present invention. Unless clearly used otherwise, the aqueous electrolyte solution 215, the number of the first expressions in the singular number include a plural meaning. electrode 220 and/or the second electrode 230, the method of In the present description, an expression Such as "compris connecting the first electrode 220 and the second electrode ing’ or “consisting of is intended to designate a character 230, the electric resistance between the first electrode 220 and istic, a number, a step, an operation, an element, a part or the second electrode 230.

combinations thereof, and shall not be construed to preclude 0073 Changing any of the above factors affects the any presence or possibility of one or more other characteris amount of electric current (that is, the amount of electrons) tics, numbers, steps, operations, elements, parts or combina flowing between the first electrode 220 and the second elec tions thereof. trode 230, thereby altering the reaction rate of the electro 0062 Unless otherwise defined, all terms, including tech chemical reaction shown in CHEMICAL FORMULA 2, nical terms and Scientific terms, used herein have the same which in turn changes the amount of hydrogen generated in meaning as how they are generally understood by those of the second electrode 230.

ordinary skill in the art to which the invention pertains. Any 0074 Therefore, the amount of the hydrogen generated in term that is defined in a general dictionary shall be construed the second electrode 230 can be controlled by controlling the to have the same meaning in the context of the relevant art, amount of the electric current that flows between the first and, unless otherwise defined explicitly, shall not be inter electrode 220 and the second electrode 230. Faraday's law preted to have an idealistic or excessively formalistic mean explains this as shown in MATHEMATICAL FORMULA 1 ing. below.

0063 Hereinafter, certain embodiments will be described MATHEMATICAL FORMULA 1 in detail with reference to the accompanying drawings. Iden i tical or corresponding elements will be given the same refer Nhydrogen = nE ence numerals, regardless of the figure number, and any redundant description of the identical or corresponding ele Nhydrogen = 2x 96485 (mol) ments will not be repeated. i 0064 FIG. 2 is a sectional view of a hydrogen generating Whydrogen = 2x 96485 X60 x 22400(mlf min) = 7Xi(mlf min) apparatus in accordance with an embodiment of the present invention.

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I0075) Where N, is the amount of hydrogen gener I0087. The modes of mobile phone depend on the cur ated per second (mol/s), V, is the Volume of hydrogen rently-working key or menu selection, and the power con generated per minute (ml/min), i is the electric current (C/s), Sumption also varies accordingly. n is the number of the reacting electrons, and E is the electron I0088 Range 301 indicates the situation of requesting a charge per mole (C/mol). call by dialing, range 302 indicates the situation of waiting a 0076. In the case of the above CHEMICAL FORMULA2, receiver's response with hearing of ring-back tone, range 303 n has a value of 2 since two electrons react at the second indicates the situation of talking over mobile phone, range electrode 230, and E has a value of -96,485 C/mol. 304 indicates the situation of ending a call, and range 305 0077. The volume of hydrogen generated per minute can indicates the situation of sending a call rate message. Since be calculated by multiplying the time (60 seconds) and the mobile phone operates different components in each of situ molar volume of hydrogen (22400 ml) to the amount of ations, the power consumption varies frequently as shown in hydrogen generated per second. FIG. 3.

0078 For example, in the case that the fuel cell is used in 0089. Therefore controller 240 receives feedback on a 2W system, and it is assumed that the fuel cell is running a power demanded for the load Such as mobile phone as shown Voltage of 0.6V at room temperature and that a hydrogen in FIG.3, and controls to generate hydrogenas much as being usage ratio is 60%, it takes 42 ml/mol of hydrogen and 6A of demanded so to provide power enough to the load coupled to electric current. In the case that the fuel cell is used in a 5W the fuel cell.

system, it takes 105 ml/mol of hydrogen and 15 A of electric 0090 The hydrogen generating apparatus may further Current. comprise an input device for user to manually input the 007.9 The hydrogen generating apparatus 200 can meet demanded amount of power or hydrogen. the variable hydrogen demand of the fuel cell connected 0091. The hydrogen generating apparatus of the present thereto by controlling the amount of electric current flowing invention can have a plurality of the first electrodes 220 through the first electric wire 225, connected to the first and/or the second electrodes 230. In the case that a plural electrode 220, and the second electric wire 235, connected to number of the first electrode 220 and/or the second electrode the second electrode 230. 230 are disposed, it can take a shorter time to generate the 0080 However, most of the factors that determine the rate demanded amount of hydrogen since the hydrogen generat of the hydrogen generation reaction occurring in the second ing apparatus 200 can generate more hydrogen per unit time. electrode of the hydrogen generating apparatus 200, except 0092 FIG. 4 is a graph showing how the amount of electric the electric resistance between the first electrode 220 and the current flowing between the first electrode 220 and the second second electrode 230, are hardly changeable once the hydro electrode 230 is related to the volume of hydrogen generated gen generating apparatus 200 is manufactured. on the second electrode 230. Here, it should be noted that the 0081. Therefore, the hydrogen generating apparatus 200 Volume of hydrogen is shown in flow-rate measured per according to this embodiment of the present invention has the minute, because not the total Volume of generated hydrogen control unit 240 disposed between the first electric wire 225 but the flow-rate of hydrogen is significant to a fuel cell. and the second electric wire 235, which connect the first (0093. An experiment for FIG.3 was conducted under the electrode 220 and the second electrode 230, in order to regu following conditions:

late the electric resistance between the first electrode 220 and First electrode 220: Magnesium (Mg) the second electrode 230.

Second electrode 230: Stainless steel 0082. Thus, the hydrogen generating apparatus 200 con trols the electric resistance between the first electrode 220 and Distance between the electrodes: 3 mm the second electrode 230, that is, the amount of the electric current flowing therebetween, thereby generating as much Ingredients and concentration of electrolyte: 30 wt % hydrogen as needed by the fuel cell. KC 0083. The first electrode 220 can be also composed of a metal having a relatively high ionization tendency, such as Number of the electrodes: Magnesium 3 each, Stain less steel 3 each iron (Fe), aluminum (Al), Zinc (Zn), or the like. The second electrode 230 can be also composed of a metal having a Electrode connecting method: Serial relatively low ionization tendency compared to the metal of the first electrode 220, such as platinum (Pt), aluminum (Al), Volume of aqueous electrolyte solution: 60 cc (exces copper (Cu), gold (Au), silver (Ag), iron (Fe), or the like. sive condition) 0084. The control unit 240 controls a transfer rate, that is, Size of the electrode: 24mmx85mmx1 mm the amount of electric current, at which electrons generated in the first electrode 220 are transferred to the second electrode 0094. The above conditions were used for every graph 230. referred to in describing the present invention. 0085. The control unit 240 receives information on power 0.095 FIG. 4 shows a greater flow rate of the hydrogen demanded for load coupled to the fuel cell and, according to than a theoretical value based on MATHEMATICAL FOR the information, maintains, or increases or reduces the MULA1, due to an interaction of the three pairs of electrodes. amount of electrons flowing from the first electrode 220 to the 0096. Nevertheless, it is verified from FIG. 4 that the flow second electrode 230. rate of hydrogen is correlated with the amount of electric I0086 For example, it will be described with reference to current between the first electrode 220 and the second elec the power consumption of mobile phone as shown in FIG. 3. trode 230. Also, the graph shows an almost linear relation FIG. 3 is a graph showing the power consumption of mobile between the flow-rate and the amount of the electric current, phone. which agrees with the MATHEMATICAL FORMULA 1.

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0097 FIG. 5 is a block diagram of the control unit 240 of fuel cell 100 is, for example, power being provided to the load the hydrogen generating apparatus in accordance with an 620 by the fuel cell 100 that receives hydrogen from the embodiment of the present invention. hydrogen generating apparatus 200. As described above, in 0098. The control unit 240 comprises a flow rate meter order to use the hydrogen generating apparatus 200 in accor 510, a switch controller 520 and a switch 530. dance with the present invention by coupling to a fuel cell, a 0099. The flow rate meter 510 measures the amount of certain amount of hydrogen generation, not a total quantity of hydrogen, in units of flow rate, generated from the second hydrogen generation, should be maintained, and thus electric electrode 230 of the hydrogen generating apparatus. As power of the fuel cell 100 based on the amount of hydrogen described above, in order to use the hydrogen generating generation is received in units of watt (W). In addition switch apparatus 200 in accordance with the present invention by controller 610 measures voltage of fuel cell 100 and converts coupling to a fuel cell, a certain amount of hydrogen genera into electric power by use of resistance. Of course, it is pos tion, not a total quantity of hydrogen generation, should be sible to use other measurement units as long as the unit is maintained, and thus it is required that the amount of hydro capable of measuring the electric power. gen generation be measured in units of ml/min. Of course, it 0108. The switch controller 610 compares the output of is possible to use other measurement units as long as the unit fuel cell 100 with the demanded powerofload 620. In case the is capable of measuring the flow rate. output of fuel cell 100 is smaller than the demanded power, 0100. The switch controller 520 is inputted with a set the switch controller 610 changes on/off time of switch 530 to value, which is related to the amount of hydrogen generation. increase the amount of hydrogen generation, and in case the The hydrogen generating apparatus 200 is disposed with a output of fuel cell 100 is greater than the demanded power, the separate input device (not shown), through which the set switch controller 610 changes on/off time of switch 520 to value can be inputted by the user. The required amount of reduce the amount of hydrogen generation. In case the output output (i.e. electric power, Voltage, current, impedance, and a of fuel cell 100 is within a certain error range compared with combination thereof) or hydrogen generation may be inputted the demanded power, current amount of hydrogen generation by a fuel cell that is coupled to the hydrogen generating is maintained. It is assumed that this Switching operation is apparatus 200. In the latter case, the fuel cell may be sepa made by a Switch control signal enabling the Switch controller rately equipped with a hydrogen requiring unit for inputting 610 to set on/off time of the Switch 530. the amount of output or hydrogen generation that is needed by 0109 FIG. 7 is a fuel cell power generation system com the hydrogen generating apparatus 200. prising controller 240 of hydrogen generating apparatus 200, 0101 The switch controller 520 compares the inputted set fuel cell coupled thereto, and a load in accordance with still value with the amount of hydrogen generation measured by another embodiment of the present invention. the flow rate meter 510. If the amount of generated hydrogen 0110. The control unit 240 includes a switch controller is smaller than the set value, the switch 530 is controlled to 710 and a switch 530. Here, the Switch 530 functions the same increase the amount of hydrogen generation, and if the way as described earlier with reference to FIG. 5, and thus amount of generated hydrogen is greater than the set value, repetitive description will be omitted. the switch 530 is controlled to reduce the amount of hydrogen 0111. When compared with the fuel cell power generation generation. It is assumed that the switch 530 is controlled by system as shown in FIG. 6, the fuel cell power generation a switch control signal such that the switch controller 520 can system in FIG. 7 further comprises a rechargeable battery turn the Switch 530 on or off.

0102 The switch is disposed between the first electrode 700. Since fuel cell has slow responsiveness, it is not possible 220 and the second electrode 230. Electrons generated in the to instantaneously respond to a peak power from the load 620. first electrode 220 is transferred to the second electrode 230 if Thus it becomes possible to respond to peak power by charg the switch 530 is turned on, and the electrons generated in the ing the rechargeable battery 700 in advance. first electrode 220 is not transferred to the second electrode 0112 The switch controller 710 measures voltage of 230 if the Switch 530 is turned off. rechargeable battery 700 to continuously generate hydrogen 0103) That is, the control unit 240 controls the amount of for the rechargeable battery 700 to be fully charged and for hydrogen generation, using the switch 530 to control whether fuel cell 100 to keep providing voltage. the electrons are to be transferred from the first electrode 220 0113 And the switch controller 710 provides the charged to the second electrode 230. voltage of rechargeable battery 700, and thus in case the 0104 FIG. 6 is a fuel cell power generation system com voltage of rechargeable battery 700 drops, makes the hydro prising controller 240 of hydrogen generating apparatus 200, gen generating apparatus 200 to generate hydrogen. fuel cell coupled thereto, and a load in accordance with 0114 Namely, the switch controller 710 compares present another embodiment of the present invention. voltage of the rechargeable battery 700 with fully-charged 0105. The control unit 240 includes a switch controller Voltage. The fully-charged Voltage means the Voltage at when 610 and a switch 530. Here, the Switch controller 610 and the the rechargeable battery 700 is fully charged. In case the switch 530 function the same way as described earlier with present Voltage is Smaller than the fully-charged Voltage, then reference to FIG. 5, and thus their description will be omitted. on/off time of switch 530 is changed to increase the amount of 0106. The switch controller 610 is coupled to the load 620 hydrogen generation, and in case the present Voltage is equal to where the fuel cell 100 provides power to. As described to or greater than the fully-charged Voltage, then on/off time above, load 620 demands different power depending on the of switch 530 is changed to stop hydrogen generation. It is currently-working condition (with reference to FIG. 3). assumed that this Switching operation is made by a Switch Therefore the switch controller 610 receives a demanded control signal enabling the switch controller 710 to set on/off power for the currently-working condition of load 620. time of the Switch 530.

0107 And, the switch controller 610 is coupled to the fuel (0.115. Here, the rechargeable battery 700 may be a super cell 100 to receive an output of the fuel cell 100. The output of capacitor or a small rechargeable battery. Super capacitor has

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the enhanced electric capacity, and can charge and discharge example of duty ratios of the Switch of a hydrogen generating the electric power if necessary. apparatus in accordance with an embodiment of the present 0116 FIG. 8 is a graph of the amount of hydrogen genera invention. FIG. 14 shows how the quantity of hydrogen gen tion, expressed in units of flow rate, when the switch is turned eration is related to time when the duty ratio of the switch is O. controlled.

0117) If the switch 530 stays on for a while, the reaction 0127. Referring to FIG. 12, the switch control signal has a becomes very fast at the beginning, raising the temperature cycle ofT and a duty ratio of 75%, that is, the switch control and rapidly increasing the amount of hydrogen generation as signal is high for 34 T and low for 4 T. much as 100 ml/min. Then, the amount of hydrogen genera 0128 Referring to FIG. 13, the switch control signal has a tion quickly drops due to the reduction of water in the aqueous cycle of T, which is the same as that of FIG. 12, and a duty electrolyte solution and the metal composing the first elec ratio of 25%, that is, the switch control signal is high for 4T trode 220. and low for 3/4 T.

0118. In such a case, it becomes difficult to control the I0129. By controlling the duty ratio of the switch control amount of hydrogen generation, and thus the amount of signal that is inputted to the switch 530, it becomes possible hydrogen generation is controlled to a desired flow rate by to control the amount of hydrogen generation per time that is having the switch controller 520 control the turning on/off of generated in the hydrogen generating apparatus 200. the switch 530 such that the switch 530 has a certain duty ratio I0130 Referring to FIG. 14, the amount of hydrogen gen and/or on/off frequency. This will be further described with eration is left to increase naturally at the beginning (refer to reference to FIG. 9. the portion of graph represented by 1420), and then the switch 0119 FIG. 9 is a first example of the on/off frequency of controller 520 controls the on and off of the switch 530 to the switch of a hydrogen generating apparatus in accordance generate 42 ml/min (1421), 10 ml/min (1422), 42 ml/min with an embodiment of the present invention, and FIG. 10 is (1423), 20 ml/min (1424) and 30 ml/min (1425) of hydrogen. a second example of the on/off frequency of the switch of a 0131 When the amount of hydrogen generation is hydrogen generating apparatus in accordance with an adjusted from 42 ml/min (1421) to 10 ml/min (1422), the ratio embodiment of the present invention. Furthermore, FIG. 11 of off-time of the switch control signal within one cycle is shows how the amount of hydrogen generation is related to increased, that is, the duty ratio is gradually decreased. Then, time when the on/off frequency of the switch is controlled. It by steadily maintaining the duty ratio when the flow rate will be assumed hereinafter that the switch 530 is turned on meter 510 reads 10 ml/min of hydrogen generation, the when the size of an inputted Switch control signal is M (i.e., amount of hydrogen generation is kept at 10 ml/min. high) and turned off when the size of an inputted switch (0132) When the amount of hydrogen generation is control signal is 0 (i.e., low). adjusted from 10 ml/min (1422) to 42 ml/min (1423), the ratio 0120 Referring to FIG.9, the switch control signal input of on-time of the switch control signal within one cycle is ted to the switch 530 has a frequency of T and a duty ratio of increased, that is, the duty ratio is gradually increased. Then, 50%. In other words, the switch control signal inputted to the by steadily maintaining the duty ratio when the flow rate switch 530 is high for '/2T and low for /2 T. meter 510 reads 42 ml/min of hydrogen generation, the 0121 Referring to FIG. 10, on the other hand, the switch amount of hydrogen generation is kept at 42 ml/min. control signal inputted to the switch 530 has a frequency of 4 I0133. By repeatedly performing the above adjustment of Tanda duty ratio of 50%. In other words, the switch control duty ratio, the switch controller 520 can adjust the amount of signal inputted to the switch 530 is high for /&T and low for hydrogen generation according to changing set values. /8 T. 0134. As described with reference to FIGS. 9 to 11, it is 0122) The switch control signal inputted to the switch 530 possible to control the fluctuation in the amount of hydrogen has a duty ratio (e.g., 50% in the case of FIGS. 9 and 10), and generation by changing the on/off frequency of the Switch thus the switch 530 is turned on and off for the same duration 530 in case a certain amount of hydrogen generation is main within one cycle. tained.

(0123 Referring to FIG. 11, when the duty ratio of the 0135 Moreover, the amount of hydrogen generation mea switch 530 is controlled such that 42ml/min of hydrogen is sured in units of flow rate in FIGS. 8, 11 and 14 may be the generated for a fuel cell that requires 2 W of electric power, amount of electric power outputted from the fuel cell 100 in a there is fluctuation in the amount of hydrogen generation hydrogen generating apparatus 200 shown in FIG. 7. For according to the on/off frequency. The temperature 1110 of example, the flow rate of 42 ml/min shown in FIGS. 8, 11 and the hydrogen generating apparatus 200 increases steadily but 14 can correspond to 2 W, depending on the operation con stays below 80° C. dition of the fuel cell 100.

0.124. The amount of hydrogen generation 1120 is close to 0.136. In other words, the earlier-measured amounts of 42 ml/min. When the on/off frequency is relatively small (i.e., hydrogen generation correspond to the output of the fuel cell a large cycle) as in FIG.9, the fluctuation is strong, as shown (i.e., electric power or voltage) that is measured by the switch in boxes represented by 1140. When the on/off frequency is controller 610, 710 as shown in FIG. 6 or 7. The amount of relatively large (i.e., a small cycle) as in FIG. 10, the fluctua hydrogen generation to be controlled through the on/off con tion is weak, as shown in boxes represented by 1150. trol of the switch corresponds to the output of the fuel cell. 0.125. Therefore, for the same duty ratio, a relatively larger that is, electric power or voltage. on/off frequency of the switch control signal causes less fluc 0.137 The switch of the hydrogen generating apparatus in tuation and is easier to maintain the desired amount of hydro accordance with an embodiment of the present invention can gen generation. be made of an MOS (metal-oxide semiconductor) transistor. 0.126 FIG. 12 is a first example of duty ratios of the switch 0.138. The switch controller of the hydrogen generating of a hydrogen generating apparatus in accordance with an apparatus in accordance with an embodiment of the present embodiment of the present invention, and FIG. 13 is a second invention can use a power circuit of the fuel cell and be

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included in a control unit of a fuel cell power generation 0.148. The switch controller 610 of the hydrogen generat system. In other words, by including the switch controller in ing apparatus 200 turns on the switch 530 and generates the control unit of a fuel cell power generation system, the hydrogen over a certain threshold of flow rate, in the step switch controller and the control unit of the fuel cell power represented by S1600.

generation system can be made into one chip. 014.9 The switch controller 610 measures output of fuel 0139 Moreover, the hydrogen generating apparatus of the cell connected to the hydrogen generating apparatus 200, and present invention can compose a fuel cell power generation receives the demanded power of load 620 connected to the system by being connected to a fuel cell. The fuel cell power fuel cell 100, in the step represented by S1610. Here, the generation system includes a hydrogen generating apparatus output of fuel cell 100 may be one of electric power or that is possible to control the amount of hydrogen generation Voltage, and in case of Voltage, electric power can be calcu and a fuel cell that generates electricity by being Supplied lated by the use of resistance.

with hydrogen from the hydrogen generating apparatus. 0150. And, the switch controller 610 compares the electric power C of fuel cell 100 with the demanded power D of load 0140 FIG. 15 is a flowchart showing a method of control 620 at step S1620.

ling the amount of hydrogen generation in a hydrogen gen 0151. According to the comparison, in case the electric erating apparatus in accordance with an embodiment of the power of fuel cell 100 is greater than the demanded power present invention. The hydrogen generatingapparatus of FIG. (C>D), the duty ratio of switch control signal is reduced at 15 is illustrated in FIG. 5. step S1630, in case the electric power of fuel cell 100 is 0141. The switch controller 520 of the hydrogen generat smaller than the demanded power (CCD), the duty ratio of ing apparatus 200 turns on the switch 530 and generates Switch control signal is increased at step S1632, and in case hydrogen over a certain threshold of flow rate, in the step the electric power of fuel cell 100 is equal to the demanded represented by S1500. power (C=D), the duty ratio of switch control signal is main 0142. In step S1510, the flow rate meter 510 measures the tained at step S1634. Here, “equal to means that the electric amount of hydrogen generation, and in step S1520 the switch power of fuel cell 100 falls within the predetermined error controller 520 compares the amount of hydrogen generation, range based on the demanded power. measured by the flow rate meter 510, with an inputted set 0152 Then, by repeating steps S1610 to S1630, S1632 or value. Here, the inputted set value can be one value, as shown S1634, the hydrogen generating apparatus 200 can control the in step S1520a, or have an upper limit and a lower limit with amount of hydrogen generation for the fuel cell to provide a range, as shown in step 1520b. output corresponding to the demanded power of load. 0143. The switch controller 520 generates a switch control (O153 FIG. 17 is a flowchart of a method of controlling the quantity of hydrogen generation in a hydrogen generating signal for controlling the on/off of the Switch according to the apparatus in accordance with another embodiment of the set value and applies the Switch control signal to the Switch present invention. The hydrogen generatingapparatus of FIG. S30. 17 is illustrated in FIG. 7.

0144. If one set value is inputted, as shown in step S1520a, 0154 By turning on the switch 530 to generate hydrogen the amount of hydrogen generation (A) and the set value (B) over a certain threshold offlow rate, the switch controller 710 are compared in step S1530a. In case the amount of hydrogen of the hydrogen generating apparatus 200 operates the fuel generation is smaller than the set value (A-B), the duty ratio cell 100 and charges the rechargeable battery 700 being con of the switch control signal is increased in step S1532a, and if nected between the fuel cell 100 and the load 620 in the step the amount of hydrogen generation is greater than the set represented by S1700.

value (AaB), the duty ratio of the switch control signal is (O155 The switch controller 710 measures the voltage of reduced in step S1534a. If the amount of hydrogen generation rechargeable battery 700 at step S1710, and compares the is equal to the set value (A=B), the current duty ratio of the fully-charged voltage F of the rechargeable battery 700 with switch control signal is maintained, in step S1536a. the present voltage E at step S1720. 0145. In case the upper limit and the lower limit are input 0156 According to the comparison, in case the present ted in step S1520b, the amount of hydrogen generation (A), Voltage is equal to or greater than the fully-charged Voltage the upper limit (B1) and the lower limit (B2) are compared in (B2F), the switch controller 710 minimizes the duty ratio of step S1530b. If the amount of hydrogen generation is smaller Switch control signal (including 0%) to prevent the recharge than the lower limit (A-B2), the duty ratio of the switch able battery 700 from being charged at step S1730, and in case control signal is increased in step S1532b, and if the amount the present Voltage is Smaller than the fully-charged Voltage of hydrogen generation is greater than the upper limit (E<F), the switch controller 710 increases the duty ratio of (A>B1), the duty ratio of the switch control signal is reduced switch control signal at step SI 732. Here, “equal to means in step S1534b. If the amount of hydrogen generation is that the present voltage falls within the predetermined error between the upper limit and the lower limit (B2s AsB1), the range based on the fully-charged Voltage. current duty ratio of the Switch control signal is maintained in (O157. Then, by repeating steps S1710 to S1730, or S1732 S1536E. the hydrogen generating apparatus 200 can control the 0146 By repeating steps S1520 to S1536a or S1536b, the rechargeable battery 700 to be fully charged for being pre hydrogen generating apparatus 200 can generate the amount pared to the peak power demanded from the load 620. of hydrogen according to the inputted set value. 0158. In the above method of controlling the amount of 0147 FIG. 16 is a flowchart showing a method of control hydrogen generation, steps S1520 to S1536a or S1536b, or ling the amount of hydrogen generation in a hydrogen gen steps S1620 to S1630 or S1632, or steps S1720 to S1730 or erating apparatus in accordance with another embodiment of S1732 can be written in a computer program. Codes and code the present invention. The hydrogen generating apparatus of segments, composing the program, can be easily realized by FIG. 16 is illustrated in FIG. 6. a computer programmer skilled in the art. Moreover, the

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program is stored in a computer readable medium, and real and the switch controller compares the set value with the izes the method of controlling the amount of hydrogen gen measured amount of hydrogen generation, and increase eration by being read and run by a computer. The computer the duty ratio if the amount of hydrogen generation is readable medium described above includes a magnetic smaller than the lower limit, reduce the duty ratio if the recording medium, an optical recording medium and a carrier amount of hydrogen generation is greater than the upper wave medium. limit, and maintain the duty ratio if the amount of hydro 0159. The drawings and detailed description are only gen generation is between the lower limit and the upper examples of the present invention, serve only for describing limit.

the present invention and by no means limit or restrict the 10. A fuel cell power generation system comprising: spirit and scope of the present invention. Thus, any person of a hydrogen generating apparatus, controlling an amount of ordinary skill in the art shall understand that a large number of hydrogen generation by controlling an on/off status of a permutations and other equivalent embodiments are possible. Switch connected between electrodes; The true scope of the present invention must be defined only a fuel cell, being Supplied with hydrogen generated by the by the ideas of the appended claims. hydrogen generating apparatus and producing a direct What is claimed is: current by converting chemical energy of the hydrogen 1. A hydrogen generating apparatus comprising: to electrical energy; and an electrolyzer, filled with an aqueous electrolyte solution; a load, being provided the electric energy and performing a a first electrode, accommodated in the electrolyzer, Sub predetermined operation.

merged in the aqueous electrolyte solution, and gener 11. The system of claim 10, in which the hydrogen gener ating electrons; ating apparatus comprises:

a second electrode, accommodated in the electrolyzer, Sub an electrolyzer, filled with an aqueous electrolyte Solution merged in the aqueous electrolyte solution, receiving the containing hydrogen ions;

electrons to generate hydrogen; a first electrode, accommodated in the electrolyzer, Sub a switch, located between the first electrode and the second merged in the aqueous electrolyte solution, and gener electrode: ating electrons;

a flow rate meter, measuring an amount of hydrogen gen a second electrode, accommodated in the electrolyzer, Sub eration in the second electrode; and merged in the aqueous electrolyte solution, receiving the a Switch controller, receiving a set value, comparing the electrons to generate hydrogen; amount of hydrogen generation measured by the flow a switch, located between the first electrode and the second rate meter with the set value, and controlling an on/off electrode; and status of the switch. a Switch controller, receiving a demanded power from the 2. The apparatus of claim 1, in which the switch controller load, measuring an output of the fuel cell, comparing the is inputted with the set value directly from a user through an demanded power with the output, and controlling an input device. on/off status of the switch. 3. The apparatus of claim 1, in which the hydrogen gener 12. The system of claim 11, in which a metal forming the ating apparatus is coupled to a fuel cell and Supplies hydro first electrode has a higher ionization tendency than a metal gen, forming the second electrode.

and the switch controller is inputted with the set value in 13. The system of claim 11, in which the switch controller accordance with an amount of hydrogen generation that generates and outputs a Switch control signal turning the is required by the fuel cell. switch on and off, 4. The apparatus of claim 1, in which a metal forming the and the switch controller determines an on/off ratio of the first electrode has a higher ionization tendency than a metal switch within one cycle by varying a duty ratio of the forming the second electrode. Switch control signal.

5. The apparatus of claim 1, in which the flow rate meter 14. The system of claim 13, in which the switch controller measures the amount of hydrogen generation in units of flow controls a fluctuation in the amount of hydrogen generation rate. by varying an on/off frequency of the Switch control signal. 6. The apparatus of claim 1, in which the switch controller 15. The system of claim 13, in which the switch controller generates and outputs a Switch control signal turning the compares the demanded power with the output, and reduces switch on and off, the duty ratio if the output is greater than the demanded and the Switch controller determines an on/off ratio of the power, increases the duty ratio if the output is smaller than the switch within one cycle by varying a duty ratio of the demanded power, and maintains the duty ratio if the output is Switch control signal. equal to the demanded power.

7. The apparatus of claim 6, in which the switch controller 16. The system of claim 10 further comprising controls a fluctuation in the amount of hydrogen generation a rechargeable battery, being coupled between the fuel cell by varying an on/off frequency of the Switch control signal. and the load, being charged by the electric energy from 8. The apparatus of claim 6, in which the switch controller the fuel cell, and providing the charged electric energy compares the set value with the measured amount of hydro when the load needs.

gen generation, and increases the duty ratio if the amount of 17. The system of claim 16, in which the hydrogen gener hydrogen generation is Smaller than the set value, reduces the ating apparatus comprises:

duty ratio if the amount of hydrogen generation is greater than an electrolyzer, filled with an aqueous electrolyte Solution the set value, and maintains the duty ratio if the amount of containing hydrogen ions;

hydrogen generation is equal to the set value. a first electrode, accommodated in the electrolyzer, Sub 9. The apparatus of claim 6, in which the set value com merged in the aqueous electrolyte solution, and gener prises an upper limit and a lower limit, ating electrons;

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a second electrode, accommodated in the electrolyzer, Sub and the step of increasing, reducing or maintaining the duty merged in the aqueous electrolyte solution, receiving the ratio is characterized by increasing a duty ratio of a electrons to generate hydrogen; Switch control signal if the amount of hydrogen genera a switch, located between the first electrode and the second tion is Smaller than the lower value, reducing the duty electrode; and ratio of the switch control signal if the amount of hydro a Switch controller, measuring a present Voltage of the gen generation is greater than the upper value, and main rechargeable battery, comparing a fully-charged Voltage taining the duty ratio of the Switch control signal if the with the present Voltage, and controlling an on/off status amount of hydrogen generation is between the lower of the Switch. value and the upper value, in which the switch control 18. The system of claim 17, in which a metal forming the signal controls the on/off status of the switch within one first electrode has a higher ionization tendency than a metal cycle in accordance with the duty ratio. forming the second electrode. 24. A method of controlling an amount of hydrogen gen 19. The system of claim 17, in which the switch controller eration in a hydrogen generating apparatus being coupled to a generates and outputs a Switch control signal turning the fuel cell of providing an electric energy to a load and control switch on and off, ling an amount of hydrogen generation by controlling an and the Switch controller determines an on/off ratio of the on/off status of a switch located between electrodes, the switch within one cycle by varying a duty ratio of the method comprising:

Switch control signal. measuring an output of the fuel cell, and receiving a 20. The system of claim 19, in which the switch controller demanded power from the load;

controls a fluctuation in the amount of hydrogen generation comparing the output with the demanded power, and by varying an on/off frequency of the Switch control signal. reducing a duty ratio of Switch control signal if the output 21. The system of claim 19, in which the switch controller is greater than the demanded power, increasing the duty compares the present Voltage with the fully-charged Voltage, ratio of Switch control signal if the output is Smaller than and increases the duty ratio if the present Voltage is Smaller the output, and maintains the duty ratio of Switch control than the fully-charged Voltage, and minimizes the duty ratio if signal if the output is equal to the output, in which the the present Voltage is equal to or greater than the fully switch control signal controls the on/off status of the charged Voltage. switch within one cycle in accordance with the duty 22. A method of controlling an amount of hydrogen gen ratio.

eration in a hydrogen generating apparatus controlling an 25. A method of controlling an amount of hydrogen gen amount of hydrogen generation by controlling an on/off sta eration in a hydrogen generating apparatus being coupled to a tus of a switch located between electrodes, the method com fuel cell of charging a rechargeable battery with an electric prising: energy and controlling an amount of hydrogen generation by being inputted with a set value; controlling an on/off status of a switch located between elec comparing a measured amount of hydrogen generation and trodes, the method comprising:

the set value; and measuring a present Voltage of the rechargeable battery; increasing a duty ratio of a Switch control signal if the comparing the present Voltage with a fully-charged Volt amount of hydrogen generation is Smaller than the set age; and value, reducing the duty ratio of the Switch control signal increasing a duty ratio of Switch control signal if the if the amount of hydrogen generation is greater than the present Voltage is Smaller than the fully-charged Voltage, set value, and maintaining the duty ratio of the Switch and minimizes the duty ratio of Switch control signal if control signal if the amount of hydrogen generation is the present Voltage is equal to or greater than the fully equal to the set value, in which the Switch control signal charged Voltage, in which the Switch control signal con controls the on/off status of the switch within one cycle trols the on/off status of the switch within one cycle in in accordance with the duty ratio. accordance with the duty ratio.

23. The method of claim 22, in which the set value com prises an upper value and a lower value, c c c c c