Fuel cell power generation system, method of controlling hydrogen generating quantity and recorded medium recorded program performing the same

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US 2011/01 04579 A1 May 5, 2011

FUEL CELL POWER GENERATION SYSTEM, 0011 Moreover, as a portable electronic device, such as a METHOD OF CONTROLLING HYDROGEN mobile phone and a notebook computer, requires a large GENERATING QUANTITY AND RECORDED capacity of power, it is necessary that the fuel cell have a large MEDIUM RECORDED PROGRAM capacity and perform high performance while it is Small. PERFORMING THE SAME 0012. In order to meet the above needs, methanol or for mic acid, permitted to be brought into an airplane by Interna

CROSS-REFERENCE TO RELATED tional Civil Aviation Organization (ICAO), is used for fuel APPLICATIONS reforming, or methanol, ethanol, or formic acid is directly used as a fuel for the fuel cell.

0001. This application is a U.S. divisional application filed 0013 However, the former case requires a high reforming under 37 USC 1.53(b) claiming priority benefit of U.S. Ser. temperature, has a complicated system, consumes driving No. 1 1/812,656 filed in the United States on Jun. 20, 2007, power, and contains impurities (e.g., CO and CO) in addition which claims earlier priority benefit to Korean Patent Appli to pure hydrogen. The latter case deteriorates power density cation No. 10-2007-0017343 filed with the Korean Intellec due to a low rate of a chemical reaction in the anode and a tual Property Office on Feb. 21, 2007, the disclosures of cross-over of hydrocarbon through the membrane. which are incorporated herein by reference.

SUMMARY

BACKGROUND

0014. The present invention provides a hydrogen generat 0002 1. Field 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. Description of the Related Art 0015 The present invention also provides a hydrogen gen 0005. A fuel cell refers to an energy conversion apparatus erating apparatus, a fuel cell power generation system, a that directly converts chemical energy of a fuel (hydrogen, method of controlling the quantity of hydrogen generation, LNG, LPG, methanol, etc.) and air to electricity and/or heat and a recorded medium recorded with a program performing by means of an electrochemical reaction. Unlike a conven the method that can control the quantity of hydrogen genera tional power generation technology that requires fuel com tion without a separate BOP (Balance of Plant) unit while bustion, steam generation, or a turbine or power generator, the maintaining a simple structure.

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

Fuel pole 110: H-->2H"+2e. Switch and reduce the noise and power consumption by not using a gas pump or a liquid pump.

Airpole 130: 1/3O+2H+2e->H.0 0019. An aspect of the present invention features a hydro Overall reaction: H+ /3O-->H-0 CHEMICAL FORMUL.A. 1 gen generating apparatus that is capable of controlling the amount of hydrogen generation.

0008. In short, the fuel cell 100 functions as a battery by 0020. The hydrogen generating apparatus in accordance Supplying the electric current, generated due to the flowing of with an embodiment of the present invention includes an the decomposed electrons, to the external circuit 140. Such a electrolyzer, which is filled with an aqueous electrolyte solu fuel cell 100 hardly emits an atmospheric pollutant such as tion containing hydrogen ions, a first electrode, which is Sox and NOx and makes little noise and vibration. accommodated in the electrolyzer, is submerged in the aque 0009 Meanwhile, in order to produce electrons in the fuel ous electrolyte Solution, and generates electrons, a second pole 110, the fuel cell 100 necessitates a hydrogen generating electrode, which is accommodated in the electrolyzer, is sub apparatus that can change a common fuel to hydrogen gas. merged in the aqueous electrolyte solution, and receives the 0010. A hydrogen storage tank, generally known as a electrons to generate hydrogen, a Switch, which is located hydrogen generating apparatus, however, occupies a large between the first electrode and the second electrode, a flow space and should be kept with care. rate meter, which measures an amount of hydrogen genera

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tion in the second electrode, and a switch controller, which generating apparatus can be coupled to the fuel cell and receives a set value, compares the amount of hydrogen gen Supply hydrogen, and the Switch controller can be inputted eration measured by the flow rate meter with the set value, and with the set value in accordance with an amount of electric controls an on/off status of the Switch. power, Voltage, current, impedance or a combination thereof 0021. The switch controller can be inputted with the set or an amount of hydrogen generation that is required by the value directly from a user through an input unit. The hydrogen fuel cell.

generating apparatus can be coupled to a fuel cell and Supplies 0029. The metal forming the first electrode can have a hydrogen, and the switch controller can be inputted with the higher ionization tendency than a metal forming the second set value in accordance with an amount of hydrogen genera electrode.

tion that is required by the fuel cell. 0030 The switch controller can generate and output a 0022. The metal forming the first electrode can have a Switch control signal turning the Switch on and off, and the higher ionization tendency than a metal forming the second switch controller can determine an on/off ratio of the switch electrode. within one cycle by varying a duty ratio of the switch control 0023 The flow rate meter can measure the amount of signal. The meter can be a flow rate meter that measures the hydrogen generation in units of flowrate. The Switch control amount of hydrogen generated in the second electrode in ler can generate and output a Switch control signal turning the units of flowrate. The switch controller can control a fluctua switch on and off, and the switch controller can determine an tion in the amount of hydrogen generation by varying an on/off ratio of the switch within one cycle by varying a duty on/off frequency of the switch control signal. The switch ratio of the Switch control signal. controller can compare the set value with the measured 0024. The switch controller can control a fluctuation in the amount of hydrogen generation, and can increase the duty amount of hydrogen generation by varying an on/off fre ratio if the amount of hydrogen generation is Smaller than the quency of the Switch control signal. The Switch controller can set value, reduce the duty ratio if the amount of hydrogen compare the set value with the measured amount of hydrogen generation is greater than the set value, and maintain the duty generation, and can increase the duty ratio if the amount of ratio if the amount of hydrogen generation is equal to the set hydrogen generation is Smaller than the set value, reduce the value. The set value can include an upper limit and a lower duty ratio if the amount of hydrogen generation is greater than limit, and the switch controller can compare the set value with the set value, and maintain the duty ratio if the amount of the measured amount of hydrogen generation, and can hydrogen generation is equal to the set value. The set value increase the duty ratio if the amount of hydrogen generation includes an upper limit and a lower limit, and the Switch is smaller than the lower limit, reduce the duty ratio if the controller can compare the set value with the measured amount of hydrogen generation is greater than the upper limit, amount of hydrogen generation, and can increase the duty and maintain the duty ratio if the amount of hydrogen gen ratio if the amount of hydrogen generation is Smaller than the eration is between the lower limit and the upper limit. lower limit, reduce the duty ratio if the amount of hydrogen 0031. The meter can be an output meter that measures an generation is greater than the upper limit, and maintain the output of the fuel cell in units of watt (W), volt (V), ampere duty ratio if the amount of hydrogen generation is between the (A), ohm (S2) or a combination thereof. The switch controller lower limit and the upper limit. can control a fluctuation in the output of the fuel cell by 0025. Another aspect of the present invention features a varying an on/off frequency of the Switch control signal. The fuel cell power generation system including a hydrogen gen switch controller can compare the set value with the measured erating apparatus that is capable of controlling the amount of output of the fuel cell, and can increase the duty ratio if the hydrogen generation. output of the fuel cell is smaller than the set value, reduce the 0026. The fuel cell power generation system in accor duty ratio if the output of the fuel cell is greater than the set dance with an embodiment of the present invention has a value, and maintain the duty ratio if the output of the fuel cell hydrogen generating apparatus, which controls an amount of is equal to the set value. The set value can include an upper hydrogen generation by controlling an on/off status of a limit and a lower limit, and the Switch controller can compare switch connected between electrodes, and a fuel cell, which is the set value with the measured output of the fuel cell, and can Supplied with hydrogen generated by the hydrogen generat increase the duty ratio if the output of the fuel cell is smaller ing apparatus and produces a direct current by converting than the lower limit, reduce the duty ratio if the output of the chemical energy of the hydrogen to electrical energy. fuel cell is greater than the upper limit, and maintain the duty 0027. The hydrogen generating apparatus can include an ratio if the output of the fuel cell is between the lower limit electrolyzer, which is filled with an aqueous electrolyte solu and the upper limit.

tion containing hydrogen ions, a first electrode, which is 0032. Another aspect of the present invention features a accommodated in the electrolyzer, is submerged in the aque method of controlling an amount of hydrogen generation in a ous electrolyte solution, and generates electrons, a second hydrogen generating apparatus controlling an amount of electrode, which is accommodated in the electrolyzer, is sub hydrogen generation by controlling an on/off status of a merged in the aqueous electrolyte solution, and receives the switch located between electrodes.

electrons to generate hydrogen, a Switch, which is located 0033. The method of controlling an amount of hydrogen between the first electrode and the second electrode, a meter, generation in accordance with an embodiment of the present which measures an amount of hydrogen generation or an invention includes the steps of being inputted with a set value; output of a fuel cell, and a switch controller, which receives a comparing a measured amount of hydrogen generation and set value, compares the amount of hydrogen generation or the the set value; and increasing a duty ratio of a Switch control output of the fuel cell measured by the meter with the set signal if the amount of hydrogen generation is Smaller than value, and controls an on/off status of the switch. the set value, reducing the duty ratio of the switch control 0028. The switch controller can be inputted with the set signal if the amount of hydrogen generation is greater than the value directly from a user through an input unit. The hydrogen set value, and maintaining the duty ratio of the Switch control

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signal if the amount of hydrogen generation is equal to the set 0041 FIG.3 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 0034. The method of controlling an amount of hydrogen the present invention;

generation in accordance with another embodiment of the 0042 FIG. 4 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 0043 FIG. 5 shows a block diagram of a control unit of a value; and increasing a duty ratio of a Switch control signal if hydrogen generating apparatus in accordance with another the amount of hydrogen generation is Smaller than the lower embodiment of the present invention; value, reducing the duty ratio of the Switch control signal if 0044 FIG. 6 is a graph indicating quantities of generated the amount of hydrogen generation is greater than the upper hydrogen, expressed in flow rate, when the Switch is turned value, and maintaining the duty ratio of the Switch control On, signal if the amount of hydrogen generation is between the 004.5 FIG. 7A shows a first example of On/Off frequen lower value and the upper value, in which the switch control cies of the Switch of a hydrogen generating apparatus in signal controls the on/offstatus of the switch within one cycle accordance with an embodiment of the present invention; in accordance with the duty ratio. 0046 FIG. 7B shows a second example of On/Off fre 0035. The method of controlling an amount of hydrogen quencies of the Switch of a hydrogen generating apparatus in generation in accordance with yet another embodiment of the accordance with an embodiment of the present invention; present invention includes the steps of being inputted with a 0047 FIG. 8 shows the relation between time and quantity set value; comparing an output of the fuel cell and the set of hydrogen generation when the On/Off frequency of the value; and increasing a duty ratio of a Switch control signal if switch is controlled;

the output of the fuel cell is smaller than the set value, reduc 0048 FIG. 9A shows a first example of duty ratios of the ing the duty ratio of the switch control signal if the output of Switch of a hydrogen generating apparatus in accordance with the fuel cell is greater than the set value, and maintaining the an embodiment of the present invention; duty ratio of the switch control signal if the output of the fuel 0049 FIG.9B shows a second example of duty ratios of cell is equal to the set value, in which the Switch control signal the Switch of a hydrogen generating apparatus in accordance controls the on/off status of the switch within one cycle in with an embodiment of the present invention; accordance with the duty ratio. 0050 FIG. 10 shows the relation between time and quan 0036. The method of controlling an amount of hydrogen tity of hydrogen generation when the duty ratio of the switch generation in accordance with yet another embodiment of the is controlled;

present invention includes the steps of being inputted with an 0051 FIG. 11 shows a flowchart of a method of control upper value and a lower value; comparing a measured output ling the quantity of hydrogen generation in a hydrogen gen of the fuel cell with the upper value and the lower value; and erating apparatus in accordance with an embodiment of the increasing a duty ratio of a Switch control signal if the output present invention; and of the fuel cell is smaller than the lower value, reducing the 0052 FIG. 12 shows a flowchart of a method of control duty ratio of the switch control signal if the output of the fuel ling the quantity of hydrogen generation in a hydrogen gen cell is greater than the upper value, and maintaining the duty erating apparatus in accordance with another embodiment of ratio of the switch control signal if the output of the fuel cell the present invention.

is between the lower value and the upper value, in which the DESCRIPTION OF EMBODIMENTS switch control signal controls the on/off status of the switch within one cycle in accordance with the duty ratio. 0053 Since there can be a variety of permutations and 0037 Another aspect of the present invention features a embodiments of the present invention, certain embodiments recording medium having recorded a computer readable pro will be illustrated and described with reference to the accom gram to control an amount of hydrogen generation in a hydro panying drawings. This, however, is by no means to restrict gen generating apparatus controlling an amount of hydrogen the present invention to certain embodiments, and shall be generation by controlling an on/off status of a Switch located construed as including all permutations, equivalents and Sub between electrodes. A program performing a method of con stitutes covered by the spirit and scope of the present inven trolling an amount of hydrogen generation described above is tion. Throughout the drawings, similar elements are given recorded in the recording medium, which is readable by a similar reference numerals. Throughout the description of the computer. present invention, when describing a certain technology is determined to evade the point of the present invention, the

BRIEF DESCRIPTION OF THE DRAWINGS pertinent detailed description will be omitted. 0054 Terms such as “first and “second can be used in 0038. These and other features, aspects and advantages of describing various elements, but the above elements shall not the present invention will become better understood with be restricted to the above terms. The above terms are used regard to the following description, appended claims and only to distinguish one element from the other. For instance, accompanying drawings where: the first element can be named the second element, and vice 0039 FIG. 1 illustrates an operational architecture of a Versa, without departing the scope of claims of the present fuel cell; invention. The term “and/or shall include the combination of 0040 FIG. 2 shows a sectional view of a hydrogen gener a plurality of listed items or any of the plurality of listed items. ating apparatus in accordance with an embodiment of the 0055 When one element is described as being “con present invention; nected' or “accessed to another element, it shall be con

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Strued as being connected or accessed to the other element 0066. The above chemical reactions can be represented as directly but also as possibly having another element in the following chemical formula 2: between. On the other hand, if one element is described as First electrode 220:Mg->Mg2+2 being “directly connected” or “directly accessed to another element, it shall be construed that there is no other element in Second electrode 230: 2H20+2->H+2(OH) between.

Overall reaction: Mg+2H2O->Mg(OH)2+HBIEMICAL FORMULA2 0056. The terms used in the description are intended to describe certain embodiments only, and shall by no means 0067. The reaction rate and the efficiency of the chemical restrict the present invention. Unless clearly used otherwise, reaction depend on various factors, including the area of the expressions in the singular number include a plural meaning. first electrode 220 and/or the second electrode 230, the con centration of the aqueous electrolyte solution 215, the type of

In the present description, an expression Such as "compris the aqueous electrolyte solution 215, the number of the first ing’ or “consisting of is intended to designate a character electrode 220 and/or the second electrode 230, the method of istic, a number, a step, an operation, an element, a part or connecting the first electrode 220 and the second electrode combinations thereof, and shall not be construed to preclude 230, the electric resistance between the first electrode 220 and any presence or possibility of one or more other characteris the second electrode 230.

tics, numbers, steps, operations, elements, parts or combina 0068 Changing any of the above factors affects the tions thereof. amount of electric current (that is, the amount of electrons) flowing between the first electrode 220 and the second elec 0057. Unless otherwise defined, all terms, including tech trode 230, thereby altering the reaction rate of the electro nical terms and Scientific terms, used herein have the same chemical reaction shown in CHEMICAL FORMULA 2, meaning as how they are generally understood by those of which in turn changes the amount of hydrogen generated in ordinary skill in the art to which the invention pertains. Any the second electrode 230.

term that is defined in a general dictionary shall be construed 0069. Therefore, the amount of the hydrogen generated in to have the same meaning in the context of the relevant art, the second electrode 230 can be controlled by controlling the and, unless otherwise defined explicitly, shall not be inter amount of the electric current that flows between the first preted to have an idealistic or excessively formalistic mean electrode 220 and the second electrode 230. Faraday's law ing. explains this as shown in MATHEMATICAL FORMULA 1 below.

0058. Hereinafter, certain embodiments will be described in detail with reference to the accompanying drawings. Iden tical or corresponding elements will be given the same refer MATHEMATICAL FORMULA 1 ence numerals, regardless of the figure number, and any i redundant description of the identical or corresponding ele Nhydrogen = nE ments will not be repeated. i 0059 FIG. 2 is a sectional view of a hydrogen generating Nhydrogen = 2x 96485 (mol) apparatus in accordance with an embodiment of the present i invention. Whydrogen = 2x 96485 x 60x22400 (ml/min) 0060 A hydrogen generating apparatus 200 includes an = 7Xi (ml/min) electrolyzer 210, a first electrode 220, a second electrode 230 and a control unit 240. For the convenience of description and understanding, it will be presumed below that the first elec I0070 where N, is the amount of hydrogen gener trode 220 is composed of magnesium (Mg) and the second ated per second (mol/S5. V, is the Volume of hydrogen electrode 230 is composed of stainless steel. generated per minute (ml/min), i is the electric current (Cfs), 0061 The electrolyzer 210 is filled with an aqueous elec is the number of the reacting electrons, and E is the electron trolyte solution 215. The aqueous electrolyte solution 215 charge per mole (C/mol).

contains hydrogen ions, which are used by the hydrogen (0071. In the case of the above CHEMICAL FORMULA2, generating apparatus 200 to generate hydrogen gas. has a value of 2 since two electrons react at the second electrode 230, and has a value of -96.485 C/mol.

0062) Examples of the electrolyte for the aqueous electro 0072 The volume of hydrogen generated per minute can lyte solution 215 are LiCl, KC1, NaCl, KNO, NaNO, CaCl, be calculated by multiplying the time (60 seconds) and the MgCl, KSO, NaSO, MgSO, AgCl, or the like. molar volume of hydrogen (22400 ml) to the amount of 0063. The electrolyzer 210 accommodates the first elec hydrogen generated per second.

trode 220 and the second electrode 230, the entirety or por 0073 For example, in the case that the fuel cell is used in tions of which are submerged in the electrolyte solution 215. a 2W system, and it is assumed that the fuel cell is running a Voltage of 0.6V at room temperature and that a hydrogen 0064. The first electrode 220 is an active electrode, where usage ratio is 60%, it takes 42 ml/mol of hydrogen and 6A of the magnesium (Mg) is oxidized to magnesium ions (Mg"), electric current. In the case that the fuel cell is used in a 5W releasing electrons due to the difference inionization energies system, it takes 105 ml/mol of hydrogen and 15 A of electric of magnesium and water. The released electrons move to the Current.

second electrode 230 through a first electric wire 225, the 0074 The hydrogen generating apparatus 200 can meet control unit 240 and a second electric wire 235. the variable hydrogen demand of the fuel cell connected 0065. The second electrode 230 is an inactive electrode, thereto by controlling the amount of electric current flowing where the water molecules receive the electrons moved from through the first electric wire 225, connected to the first the first electrode 220 and then are decomposed into the electrode 220, and the second electric wire 235, connected to hydrogen molecules. the second electrode 230.

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0075. However, most of the factors that determine the rate I0088. Number of the electrodes: Magnesium 3 each, of the hydrogen generation reaction occurring in the second Stainless steel 3 each electrode of the hydrogen generating apparatus 200, except 0089 Electrode connecting method: Serial the electric resistance between the first electrode 220 and the second electrode 230, are hardly changeable once the hydro 0090 Volume of aqueous electrolyte solution: 60 cc (ex gen generating apparatus 200 is manufactured. cessive condition) 0076. Therefore, the hydrogen generating apparatus 200 0091 Size of the electrode: 24mmx85 mmx1 mm according to this embodiment of the present invention has the 0092. The above conditions were used for every graph control unit 240 disposed between the first electric wire 225 referred to in describing the present invention. and the second electric wire 235, which connect the first 0093 FIG. 3 shows a greater flow rate of the hydrogen electrode 220 and the second electrode 230, in order to regu than a theoretical value based on MATHEMATICAL FOR late the electric resistance between the first electrode 220 and the second electrode 230. MULA1, due to an interaction of the three pairs of electrodes. 0077. Thus, the hydrogen generating apparatus 200 con 0094. Nevertheless, it is verified from FIG.3 that the flow trols the electric resistance between the first electrode 220 and rate of hydrogen is correlated with the amount of electric the second electrode 230, that is, the amount of the electric current between the first electrode 220 and the second elec current flowing therebetween, thereby generating as much trode 230. Also, the graph shows an almost linear relation hydrogen as needed by the fuel cell. between the flow-rate and the amount of the electric current, 0078. The first electrode 220 can be also composed of a which agrees with the MATHEMATICAL FORMULA 1. metal having a relatively high ionization tendency, such as (0095 FIG. 4 is a block diagram of the control unit 240 of iron (Fe), aluminum (Al), Zinc (Zn), or the like. The second the hydrogen generating apparatus in accordance with an electrode 230 can be also composed of a metal having a embodiment of the present invention. relatively low ionization tendency compared to the metal of the first electrode 220, such as platinum (Pt), aluminum (Al), 0096. The control unit 240 comprises a flow rate meter copper (Cu), gold (Au), silver (Ag), iron (Fe), or the like. 410, a Switch controller 420 and a switch 430. 0079. The control unit 240 controls a transfer rate, that is, 0097. The flow rate meter 410 measures the amount of the amount of electric current, at which electrons generated in hydrogen, in units of flow rate, generated from the second the first electrode 220 are transferred to the second electrode electrode 230 of the hydrogen generating apparatus. As 230. described above, in order to use the hydrogen generating 0080. The control unit 240 receives information on the apparatus 200 in accordance with the present invention by amount of power or hydrogen demanded for the fuel cell and, coupling to a fuel cell, a certain amount of hydrogen genera according to the information, controls the amount of electrons tion, not a total quantity of hydrogen generation, should be flowing from the first electrode 220 to the second electrode maintained, and thus it is required that the amount of hydro 230. If the demanded amount of power or hydrogen is large, gen generation be measured in units of ml/min. Of course, it the control unit 240 increases the amount of electrons, and the is possible to use other measurement units as long as the unit control unit 240 reduces the amount of the electrons if the is capable of measuring the flow rate. demanded amount of power or hydrogen is Small. (0098. The switch controller 420 is inputted with a set 0081. The hydrogen generating apparatus 200 can receive value, which is related to the amount of hydrogen generation. the information on the amount of the power or the hydrogen The hydrogen generating apparatus 200 is disposed with a demanded for the fuel cell from the fuel cell combined with separate input unit (not shown), through which the set value the hydrogen generating apparatus 200 or from a user, who can be inputted by the user. The required amount of output inputs the information through a separate input unit. (i.e. electric power, Voltage, current, impedance, or a combi 0082. The hydrogen generating apparatus of the present nation thereof) or hydrogen generation may be inputted by a invention can have a plurality of the first electrodes 220 fuel cell that is coupled to the hydrogen generating apparatus and/or the second electrodes 230. In the case that a plural 200. In the latter case, the fuel cell may be separately number of the first electrode 220 and/or the second electrode equipped with a hydrogen requiring unit for inputting the 230 are disposed, it can take a shorter time to generate the amount of output or hydrogen generation that is needed by the demanded amount of hydrogen since the hydrogen generat hydrogen generating apparatus 200. ing apparatus 200 can generate more hydrogen per unit time. (0099. The switch controller 420 compares the inputted set 0083 FIG.3 is a graph showing how the amount of electric value with the amount of hydrogen generation measured by current flowing between the first electrode 220 and the second the flow rate meter 410. If the amount of generated hydrogen electrode 230 is related to the volume of hydrogen generated is smaller than the set value, the switch 430 is controlled to on the second electrode 230. Here, it should be noted that the increase the amount of hydrogen generation, and if the Volume of hydrogen is shown in flow-rate measured per amount of generated hydrogen is greater than the set value, minute, because not the total Volume of generated hydrogen the switch 430 is controlled to reduce the amount of hydrogen but the flow-rate of hydrogen is significant to a fuel cell. generation. It is assumed that the switch 430 is controlled by An Experiment for FIG. 3 was Conducted Under the Follow a switch control signal such that the switch controller 420 can turn the Switch 430 on or off.

ing Conditions:

0100. The switch is disposed between the first electrode 0084 First electrode 220: Magnesium (Mg) 220 and the second electrode 230. Electrons generated in the 0085. Second electrode 230: Stainless steel first electrode 220 is transferred to the second electrode 230 if 0.086 Distance between the electrodes: 3 mm the switch 430 is turned on, and the electrons generated in the 0087 Ingredients and concentration of electrolyte: 30 wt first electrode 220 is not transferred to the second electrode % KC1 230 if the Switch 430 is turned off.

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0101 That is, the control unit 240 controls the amount of 0111 Referring to FIG. 7A, the switch control signal hydrogen generation, using the Switch 430 to control whether inputted to the switch 430 has a frequency of T and a duty the electrons are to be transferred from the first electrode 220 ratio of 50%. In other words, the switch control signal input to the second electrode 230. ted to the switch 430 is high for /2T and low for /2 T. 0102 FIG. 5 is a block diagram of the control unit 240 of (O112 Referring to FIG. 7B, on the other hand, the switch the hydrogen generating apparatus in accordance with control signal inputted to the switch 430 has a frequency of 4 another embodiment of the present invention. T and a duty ratio of 50%. In other words, the switch control 0103) The control unit 240 includes an output meter 510, a signal inputted to the switch 430 is high for /s T and low for switch controller 420 and a switch 430. Here, the Switch /8 T.

controller 420 and the switch 430 function the same way as 0113. The switch control signal inputted to the switch 430 described earlier with reference to FIG. 4, and thus their has a duty ratio (e.g., 50% in the case of FIGS. 7A and 7B). description will be omitted. and thus the switch 430 is turned on and off for the same 0104. The output meter 510 is connected to the fuel cell duration within one cycle.

100 to measure an output of the fuel cell 100. Here, the output 0114 Referring to FIG. 8, when the duty ratio of the refers to, for example, the amount of electric power, Voltage, switch 430 is controlled such that 42 ml/min of hydrogen is current, impedance or a combination thereof of the fuel cell generated for a fuel cell that requires 2 W of electric power, 100 that receives hydrogen, which is generated from the there is fluctuation in the amount of hydrogen generation hydrogen generating apparatus 200. The below description according to the on/off frequency. The temperature 810 of the will focus on electric power as the output of the fuel cell. hydrogen generating apparatus 200 increases steadily but 0105. As described above, a certain amount of hydrogen stays below 80° C.

generation during certain duration, not a total amount of 0115 The amount of hydrogen generation 820 is close to hydrogen generation, has to be maintained in order to use the 42 ml/min. When the on/off frequency is relatively small (i.e., hydrogen generating apparatus 200 in accordance with an a large cycle) as in FIG. 7A, the fluctuation is strong, as shown embodiment of the present invention by coupling with the in boxes represented by 840. When the on/off frequency is fuel cell. Therefore, the amount of electric power of the fuel relatively large (i.e., a small cycle) as in FIG. 7B, the fluctua cell 100 based on the amount of hydrogen generation is mea tion is weak, as shown in boxes represented by 850. sured in units of watt (W). Ofcourse, it is possible to use other 0116. Therefore, for the same duty ratio, a relatively larger units as long as the amount of electric power can be measured. on/off frequency of the Switch control signal causes less fluc 0106 Although the below description focuses on the con tuation and is easier to maintain the desired amount of hydro gen generation.

trol with the Switch 430 of a hydrogen generating apparatus 0117 FIG.9A is a first example ofduty ratios of the switch that is equipped with the flow rate meter 410 shown in FIG.4, of a hydrogen generating apparatus in accordance with an it shall be evident that the same description applies to a embodiment of the present invention, and FIG.9B is a second hydrogen generating apparatus 200 equipped with the output example of duty ratios of the Switch of a hydrogen generating meter 510 shown in FIG. 5.

apparatus in accordance with an embodiment of the present 0107 FIG. 6 is a graph of the amount of hydrogen genera invention. FIG. 10 shows how the quantity of hydrogen gen tion, expressed in units of flow rate, when the switch 430 is eration is related to time when the duty ratio of the switch is turned on. controlled.

0108 If the switch 430 stays on for a while, the reaction 0118 Referring to FIG.9A, the switch control signal has a becomes very fast at the beginning, raising the temperature cycle of T and a duty ratio of 75%, that is, the switch control and rapidly increasing the amount of hydrogen generation as signal is high for 3/4 T and low for 4 T. much as 100 ml/min. Then, the amount of hydrogen genera 0119 Referring to FIG.9B, 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. 9A, 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.

0109. In such a case, it becomes difficult to control the 0.120. 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 430, 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 420 control the turning on/off of generated in the hydrogen generating apparatus 200. the switch 430 such that the switch 430 has a certain duty ratio I0121 Referring to FIG. 10, 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. 7A. the portion of graph represented by 1020), and then the switch 0110 FIG. 7A is a first example of the on/off frequency of controller 420 controls the on and off of the switch 430 to the Switch of a hydrogen generating apparatus in accordance generate 42 ml/min (1021), 10 ml/min (1022), 42 ml/min with an embodiment of the present invention, and FIG. 7B is (1023), 20 ml/min (1024) and 30 ml/min (1025) of hydrogen. a second example of the on/off frequency of the switch of a I0122) When the amount of hydrogen generation is hydrogen generating apparatus in accordance with an adjusted from 42 ml/min (1021) to 10 ml/min (1022), the ratio embodiment of the present invention. Furthermore, FIG. 8 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 430 is turned on meter 410 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 I0123. When the amount of hydrogen generation is control signal is 0 (i.e., low). adjusted from 10 ml/min (1022) to 42 ml/min (1023), the ratio

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of on-time of the Switch control signal within one cycle is I0134. The switch controller 420 generates a switch control increased, that is, the duty ratio is gradually increased. Then, signal for controlling the on/off of the Switch according to the by steadily maintaining the duty ratio when the flow rate set value and applies the Switch control signal to the Switch meter 410 reads 42 ml/min of hydrogen generation, the 430.

amount of hydrogen generation is kept at 42 ml/min. I0135) If one set value is inputted, as shown in step S1120a, 0.124. By repeatedly performing the above adjustment of the amount of hydrogen generation (A) and the set value (B) duty ratio, the switch controller 420 can adjust the amount of are compared in step S1130a. In case the amount of hydrogen hydrogen generation according to changing set values. generation is smaller than the set value (A-B), the duty ratio of the switch control signal is increased in step S1132a, and if 0.125. As described with reference to FIGS. 7A to 8, it is the amount of hydrogen generation is greater than the set possible to control the fluctuation in the amount of hydrogen value (AB), the duty ratio of the switch control signal is generation by changing the on/off frequency of the Switch reduced in step S1134a. If the amount of hydrogen generation 430 in case a certain amount of hydrogen generation is main is equal to the set value (A=B), the current duty ratio of the tained. Switch control signal is maintained, in step S1136.a. 0126. Moreover, the amount of hydrogen generation mea 0.136. In case the upper limit and the lower limit are input sured in units of flow rate in FIGS. 6 to 10 may be the amount ted in step S1120b, the amount of hydrogen generation (A), of electric power outputted from the fuel cell 100 in a hydro the upper limit (B1) and the lower limit (B2) are compared in gen generating apparatus 200 shown in FIG. 5. For example, step 1130b. If the amount of hydrogen generation is smaller the flow rate of 42 ml/min shown in FIGS. 6 to 10 can than the lower limit (A-B2), the duty ratio of the switch correspond to 2 W, depending on the operation condition of control signal is increased in step 1132b, and if the amount of the fuel cell 100. hydrogen generation is greater than the upper limit (AB1). the duty ratio of the Switch control signal is reduced in step 0127. In other words, the earlier-measured amounts of S1134b. If the amount of hydrogen generation is between the hydrogen generation correspond to the output of the fuel cell upper limit and the lower limit (B2=A=B1), the current duty (i.e., amount of electric power) that is measured by the output ratio of the switch control signal is maintained in S1136b. meter 510 of the hydrogen generating apparatus 200. The I0137. By repeating steps S1120 to S1136a or S1136b, the amount of hydrogen generation to be controlled through the hydrogen generating apparatus 200 can generate the amount on/off control of the switch corresponds to the output of the of hydrogen according to the inputted set value. fuel cell, that is, the amount of electric power. I0138 FIG. 12 is a flowchart showing a method of control 0128. The Switch of the hydrogen generating apparatus in ling the amount of hydrogen generation in a hydrogen gen accordance with an embodiment of the present invention can erating apparatus in accordance with another embodiment of be made of an MOS (metal-oxide semiconductor) transistor. the present invention. The hydrogen generating apparatus of FIG. 12 is illustrated in FIG.S.

0129. The switch controller of the hydrogen generating 0.139. The switch controller 420 of the hydrogen generat apparatus in accordance with an embodiment of the present ing apparatus 200 turns on the switch 430 and generates invention can use a power circuit of the fuel cell and be hydrogen over a certain threshold of flow rate, in the step included in a control unit of a fuel cell generating system. In represented by S1200.

other words, by including the switch controller in the control 0140. The output meter 510 measures the output (e.g., unit of a fuel cell generating system, the Switch controller and amount of electric power) of the fuel cell, in the step repre the control unit of the fuel cell generating system can be made sented by S1210, and the switch controller 420 compares the into one chip. output of the fuel cell, measured by the output meter 510, and 0130. Moreover, the hydrogen generating apparatus of the the inputted set value in S1220. Here, the inputted set value present invention can compose a fuel cell generating system can be one value, as shown in S1220a, or have an upper limit by being connected to a fuel cell. The fuel cell generating and a lower limit with a range, as shown in S1220b. system includes a hydrogen generating apparatus that is pos 0.141. The switch controller 420 generates a switch control sible to control the amount of hydrogen generation and a fuel signal for controlling the on/off of the switch 430 according to cell that generates electricity by being supplied with hydro the set value and applies the Switch control signal to the gen from the hydrogen generating apparatus. Switch 430.

0131 FIG. 11 is a flowchart showing a method of control 0142. If one set value is inputted, as shown in S1220a, the ling the amount of hydrogen generation in a hydrogen gen output of the fuel cell (A) and the set value (B) are compared erating apparatus in accordance with an embodiment of the in S1230a. In case the output of the fuel cell is smaller than the present invention. The hydrogen generatingapparatus of FIG. set value (A-B), the duty ratio of the switch control signal is 11 is illustrated in FIG. 4. increased in S1232a, and if the output of the fuel cell is greater 0132) The switch controller 420 of the hydrogen generat than the set value (A-B), the duty ratio of the switch control ing apparatus 200 turns on the switch 430 and generates signal is reduced in S1234a. If the output of the fuel cell is hydrogen over a certain threshold of flow rate, in the step equal to the set value (A=B), the current duty ratio of the represented by S1100. switch control signal is maintained in S1236a. 0133. In step S1110, the flow rate meter 410 measures the 0143. In case the upper limit and the lower limit are input amount of hydrogen generation, and in step S1120 the Switch ted in step S1220b, the amount of hydrogen generation (A), controller 420 compares the amount of hydrogen generation, the upper limit (B1) and the lower limit (B2) are compared in measured by the flow rate meter 410, with an inputted set step 1230b. If the amount of hydrogen generation is smaller value. Here, the inputted set value can be one value, as shown than the lower limit (A-B2), the duty ratio of the switch in step S1120a, or have an upper limit and a lower limit with control signal is increased in step 1232b, and if the amount of a range, as shown in step 1120b. hydrogen generation is greater than the upper limit (AB1).

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the duty ratio of the Switch control signal is reduced in step 5. The system of claim 2, in which a metal forming the first S1234b. If the amount of hydrogen generation is between the electrode has a higher ionization tendency than a metal form upper limit and the lower limit (B2=A=B1), the current duty ing the second electrode.

ratio of the switch control signal is maintained in S1236b. 6. The system of claim 2, in which the switch controller 0144. By repeating steps S2120 to S1236a or S1236b, the generates and outputs a Switch control signal turning the hydrogen generating apparatus 200 can generate the amount Switch on and off, and of hydrogen according to the inputted set value. the switch controller determines an on/off ratio of the 0145. In the above method of controlling the amount of switch within one cycle by varying a duty ratio of the hydrogen generation, steps S1120 to S1136a or 1136b, or Switch control signal.

steps S1220 to S1236a or 1236b, can be written in a computer 7. The system of claim 6, in which the meter is a flow rate program. Codes and code segments, composing the program, meter that measures the amount of hydrogen generated in the can be easily realized by a computer programmer skilled in second electrode in units of flowrate. the art. Moreover, the program is stored in a computer read 8. The system of claim 7, in which the switch controller able medium, and realizes the method of controlling the controls a fluctuation in the amount of hydrogen generation amount of hydrogen generation by being read and run by a by varying an on/off frequency of the Switch control signal. computer. The computer readable medium described above 9. The system of claim 7, in which the switch controller includes a magnetic recording medium, an optical recording compares the set value with the measured amount of hydro medium and a carrier wave medium. gen generation, and increases the duty ratio if the amount of 0146 The drawings and detailed description are only hydrogen generation is Smaller than the set value, reduces the examples of the present invention, serve only for describing duty ratio if the amount of hydrogen generation is greater than the present invention and by no means limit or restrict the the set value, and maintains the duty ratio if the amount of spirit and scope of the present invention. Thus, any person of hydrogen generation is equal to the set value. ordinary skill in the art shall understand that a large number of 10. The system of claim 7, in which the set value comprises permutations and other equivalent embodiments are possible. an upper limit and a lower limit, and The true scope of the present invention must be defined only the switch controller compares the set value with the mea by the ideas of the appended claims. Sured amount of hydrogen generation, and increases the What is claimed is:

duty ratio if the amount of hydrogen generation is 1. A fuel cell power generation system comprising: smaller than the lower limit, reduces the duty ratio if the amount of hydrogen generation is greater than the upper a hydrogen generating apparatus, controlling an amount of limit, and maintains the duty ratio if the amount of hydrogen generation by controlling an on/off status of a hydrogen generation is between the lower limit and the Switch connected between electrodes; and upper limit.

a fuel cell, being Supplied with hydrogen generated by the 11. The system of claim 6, in which the meter is an output hydrogen generating apparatus and producing a direct meter that measures an output of the fuel cell in units of watt current by converting chemical energy of the hydrogen (W), volt (V), ampere (A), ohm (S2) or a combination thereof. to electrical energy. 12. The system of claim 11, in which the switch controller 2. The system of claim 1, in which the hydrogen generating controls a fluctuation in the output of the fuel cell by varying apparatus comprises: an on/off frequency of the Switch control signal. an electrolyzer, filled with an aqueous electrolyte Solution 13. The system of claim 11, in which the switch controller containing hydrogen ions; compares the set value with the measured output of the fuel a first electrode, accommodated in the electrolyzer, Sub cell, and increases the duty ratio if the output of the fuel cell merged in the aqueous electrolyte solution, and gener is smaller than the set value, reduces the duty ratio if the ating electrons; output of the fuel cell is greater than the set value, and main a second electrode, accommodated in the electrolyzer, Sub tains the duty ratio if the output of the fuel cell is equal to the merged in the aqueous electrolyte solution, receiving the set value.

electrons to generate hydrogen; 14. The system of claim 11, in which the set value com a switch, located between the first electrode and the second prises an upper limit and a lower limit, and electrode: the switch controller compares the set value with the mea a meter, measuring an amount of hydrogen generation oran sured output of the fuel cell, and increases the duty ratio output of a fuel cell; and if the output of the fuel cell is smaller than the lower a Switch controller, receiving a set value, comparing the limit, reduces the duty ratio if the output of the fuel cell amount of hydrogen generation or the output of the fuel is greater than the upper limit, and maintains the duty cell measured by the meter with the set value, and con ratio if the output of the fuel cell is between the lower trolling an on/off status of the switch. limit and the upper limit.

3. The system of claim 2, in which the switch controller is 15. A method of controlling an amount of hydrogen gen inputted with the set value directly from a user through an eration in a hydrogen generating apparatus controlling an input unit. amount of hydrogen generation by controlling an on/off sta 4. The system of claim 2, in which the hydrogen generating tus of a switch located between electrodes, the method com apparatus is coupled to the fuel cell and Supplies hydrogen, prising:

and being inputted with a set value; the switch controller is inputted with the set value in accor comparing a measured amount of hydrogen generation and dance with an amount of electric power, Voltage, current, the set value; and impedance or a combination thereof or an amount of increasing a duty ratio of a Switch control signal if the hydrogen generation that is required by the fuel cell. amount of hydrogen generation is Smaller than the set

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value, reducing the duty ratio of the Switch control signal being inputted with an upper value and a lower value; if the amount of hydrogen generation is greater than the comparing a measured output of the fuel cell with the upper set value, and maintaining the duty ratio of the Switch value and the lower value; and control signal if the amount of hydrogen generation is increasing a duty ratio of a Switch control signal if the equal to the set value, in which the Switch control signal output of the fuel cell is smaller than the lower value, controls the on/off status of the switch within one cycle reducing the duty ratio of the switch control signal if the in accordance with the duty ratio. output of the fuel cell is greater than the upper value, and 16. A method of controlling an amount of hydrogen gen maintaining the duty ratio of the Switch control signal if eration in a hydrogen generating apparatus controlling an the output of the fuel cell is between the lower value and amount of hydrogen generation by controlling an on/off sta the upper value, in which the Switch control signal con tus of a switch located between electrodes, the method com trols the on/off status of the switch within one cycle in prising: accordance with the duty ratio. being inputted with an upper value and a lower value; 19. A recording medium having recorded a computer read comparing a measured amount of hydrogen generation able program to control an amount of hydrogen generation in with the upper value and the lower value; and a hydrogen generating apparatus controlling an amount of increasing a duty ratio of a Switch control signal if the hydrogen generation by controlling an on/off status of a amount of hydrogen generation is Smaller than the lower switch located between electrodes, in which the recording value, reducing the duty ratio of the Switch control signal medium, being readable by a computer, having recorded a if the amount of hydrogen generation is greater than the program performing a method of controlling an amount of upper value, and maintaining the duty ratio of the Switch hydrogen generation of claim 15.

control signal if the amount of hydrogen generation is 20. A recording medium having recorded a computer read between the lower value and the upper value, in which able program to control an amount of hydrogen generation in the switch control signal controls the on/off status of the a hydrogen generating apparatus controlling an amount of switch within one cycle in accordance with the duty hydrogen generation by controlling an on/off status of a ratio. switch located between electrodes, in which the recording 17. A method of controlling an amount of hydrogen gen medium, being readable by a computer, having recorded a eration in a hydrogen generating apparatus controlling an program performing a method of controlling an amount of amount of hydrogen generation by controlling an on/off sta hydrogen generation of claim 16. tus of a switch that is connected to a fuel cell and located 21. A recording medium having recorded a computer read between electrodes, the method comprising: able program to control an amount of hydrogen generation in being inputted with a set value; a hydrogen generating apparatus controlling an amount of comparing an output of the fuel cell and the set value; and hydrogen generation by controlling an on/off status of a increasing a duty ratio of a Switch control signal if the switch located between electrodes, in which the recording output of the fuel cell is smaller than the set value, medium, being readable by a computer, having recorded a reducing the duty ratio of the switch control signal if the program performing a method of controlling an amount of output of the fuel cell is greater than the set value, and hydrogen generation of claim 17.

maintaining the duty ratio of the Switch control signal if 22. A recording medium having recorded a computer read the output of the fuel cell is equal to the set value, in able program to control an amount of hydrogen generation in which the switch control signal controls the on/offstatus a hydrogen generating apparatus controlling an amount of of the switch within one cycle in accordance with the hydrogen generation by controlling an on/off status of a duty ratio. switch located between electrodes, in which the recording 18. A method of controlling an amount of hydrogen gen medium, being readable by a computer, having recorded a eration in a hydrogen generating apparatus controlling an program performing a method of controlling an amount of amount of hydrogen generation by controlling an on/off sta hydrogen generation of claim 18. tus of a switch that is connected to a fuel cell and located between electrodes, the method comprising: c c c c c