JP2006047065A - Solution concentration measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid fuel concentration sensor or the like having a simple structure and high measuring precision. <P>SOLUTION: Since a polymer film 665, which has a property increased in its swelling ratio with an increase in the concentration of the alcohol in fuel, constituting a sensor 668 is used, if the concentration of the alcohol in the fuel is increased, the number density of the conductive fillers 1,688 in a composite membrane 1,686 is reduced with the increase in the concentration of the alcohol in the fuel. Since the number of electrical contact points between the respective conductive fillers 1,688 present in the composite membrane 1,686 is reduced, the electric resistance value of the composite membrane 1,686 is increased when a current is allowed to flow to the composite membrane 1,686. Accordingly, the concentration of the alcohol in the fuel can be measured by measuring the electric resistance value using first and second electrode terminals 666 and 667 to monitor a change in the electric resistance value of the composite membrane 1,686. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a solution concentration measuring apparatus and use of the apparatus for a fuel cell.

  A fuel cell is composed of a fuel electrode and an oxidant electrode, and an electrolyte provided therebetween. The fuel cell is supplied with fuel, and the oxidant electrode is supplied with an oxidant to generate electricity by an electrochemical reaction. In general, hydrogen is used as the fuel. However, in recent years, development of a direct type fuel cell that directly supplies the fuel electrode with alcohol such as methanol that is inexpensive and easy to handle has been actively performed. .

  When hydrogen is used as the fuel, the reaction at the fuel electrode is represented by the following formula (1).

3H ₂ → 6H ⁺ + 6e ⁻ (1)

  When methanol is used as the fuel, the reaction at the fuel electrode is represented by the following equation (2).

CH ₃ OH + H ₂ O → 6H ⁺ + CO ₂ + 6e ⁻ (2)

  In either case, the reaction at the oxidant electrode is represented by the following formula (3).

3 / 2O ₂ + 6H ⁺ + 6e ⁻ → 3H ₂ O (3)

  In particular, in a direct fuel cell, hydrogen ions can be obtained from an aqueous alcohol solution, so that a reformer or the like is not required, and the size and weight can be reduced. In addition, since a liquid alcohol aqueous solution is used as a fuel, the energy density is very high.

  However, in the direct fuel cell, the alcohol concentration in the fuel changes depending on the power generation situation. In order to keep the power of the fuel cell stable, it is necessary to keep the alcohol concentration in the fuel within an appropriate range. Therefore, an apparatus for detecting the alcohol concentration in the fuel is required for the fuel cell system.

  For example, Patent Document 1 and Patent Document 2 include an anode and a cathode sandwiching an electrolyte membrane (see FIG. 15 of Patent Document 1 and FIG. 6 of Patent Document 2). A sensor for measuring methanol concentration is disclosed. In this cell, a catalyst electrode such as Pt—Ru is used as the anode and Pt is used as the cathode. By applying a constant voltage between the anode and cathode of the cell thus configured, a reaction occurs in which methanol is converted to carbon dioxide at the anode and protons are converted to hydrogen at the cathode, and current flows between the anode and cathode. Flows. By measuring the current value generated between the anode and the cathode by this electrode reaction, the methanol concentration in the liquid is measured.

US Pat. No. 6,254,748 US Pat. No. 6,306,285

  However, in the case of the sensors having the configurations disclosed in Patent Document 1 and Patent Document 2, since the configuration of the fuel cell is adopted, the configuration is complicated and high power is consumed. Further, since hydrogen gas is generated at the cathode, it is necessary to remove the generated hydrogen gas. Furthermore, when measuring the alcohol concentration, it may be affected by external factors such as the pH of a solution containing alcohol.

  An object of the present invention is to solve the above-described problems of the prior art, and to provide a concentration measuring device that has a simple configuration, consumes less power, and is less susceptible to pH.

  According to the present invention, when immersed in a liquid containing a predetermined component, the polymer film that changes dimensions according to the concentration of the predetermined component in the liquid, the conductive filler mixed in the polymer film, and the polymer There is provided a solution concentration measuring device including at least a pair of electrode terminals disposed on a membrane.

  In the present invention, the polymer film is made of a material whose dimensions change depending on the concentration of a predetermined component, and is immersed in a liquid containing the predetermined component. In such a polymer film, as the size of the polymer film increases, the number (number density) of conductive fillers per unit volume decreases. As a result, the distance between the conductive fillers is increased, so that the number of electrical contact points is reduced, and the number of current paths between at least a pair of electrode terminals disposed on the polymer film is reduced. Conversely, as the dimensions are reduced, the number of electrical contact points between the conductive fillers in the polymer film increases and the number of current paths increases. Therefore, the concentration change of the predetermined component in the liquid can be measured as the resistance change of the polymer film.

As described above, in the solution concentration measuring apparatus of the present invention, the number of electrical contacts between the conductive fillers changes, thereby changing the number of current paths between the electrode terminals. For this reason, an accurate measured value can be obtained stably.
Further, the measurement method employed by the present invention is not easily affected by the pH of the liquid, as will be described later in the Examples section.

  According to the solution concentration measuring apparatus of the present invention, by measuring the resistance value of the polymer film using at least a pair of electrode terminals, the concentration of a predetermined component in the liquid can be detected, and the measurement unit is a fuel cell. Therefore, the concentration of the predetermined component in the liquid can be detected using a solution concentration measuring device having a simple structure, and it is not necessary to remove the generated hydrogen.

  According to the present invention, there is provided a fuel container for a fuel cell comprising any one of the above solution concentration measuring devices.

  According to the present invention, a fuel cell system using a liquid fuel containing alcohol, the fuel cell including a solid polymer electrolyte membrane, and a fuel electrode and an oxidant electrode arranged on the solid polymer electrolyte membrane A main body, a container for storing the liquid fuel, and (a) a polymer film that changes dimensions according to the concentration of the predetermined component in the liquid when immersed in the liquid fuel containing the predetermined component; A fuel cell system comprising: a conductive filler mixed in a polymer membrane; and (c) a solution concentration measuring device for a fuel cell comprising at least a pair of electrode terminals disposed in the polymer membrane. Is done.

  Here, the fuel cell main body may be a direct type that directly supplies liquid fuel to the fuel electrode, or may be one that reforms the liquid fuel and uses hydrogen as the fuel. The liquid fuel container includes a fuel electrode tank provided at the fuel electrode of the fuel cell main body, a fuel tank for storing fuel supplied to the fuel electrode tank, a cartridge, or a pipe connecting them, and a polymer film impregnated with liquid fuel Any configuration is possible if possible.

  According to the fuel cell system of the present invention, the alcohol concentration of the liquid fuel can be detected with a small amount of electric power by using a solution concentration measuring device having a simple structure and high measurement accuracy as compared with the conventional technology. A fuel cell system can be realized.

  According to the fuel cell system of the present invention, since the concentration of the predetermined component of the liquid fuel is detected by measuring the resistance value of the polymer film based on the number of electrical contact points between the conductive fillers, the influence of pH is reduced. By making it difficult to receive, a fuel cell system capable of accurately detecting the alcohol concentration of the liquid fuel can be realized.

  According to the present invention, it has a simpler structure than the prior art comprising at least a concentration detection unit of a predetermined component immersed in a liquid, a polymer film and a pair of electrode terminals disposed thereon, and Since the concentration of the predetermined component in the liquid is detected using the electric resistance characteristics of the polymer film, a solution concentration measuring device with high measurement accuracy is provided by making it less susceptible to the influence of pH.

  The application of the fuel cell system described in the following embodiments is not particularly limited. For example, a portable personal computer such as a mobile phone or a notebook type, a PDA (Personal Digital Assistant), various cameras, a navigation system, a portable music player, etc. Appropriately used for small electrical equipment. Moreover, in the following embodiment, the form using the sensor which measures the density | concentration of alcohol among the predetermined components in a fuel is demonstrated.

First Embodiment FIG. 1 shows the conductivity in a composite film 1686 composed of a polymer film 665 and a conductive filler 1688 constituting a sensor 668 in accordance with a change in the concentration of alcohol as a predetermined component of fuel. It is a figure for demonstrating typically the change of the particle | grain presence state of the filler 1688. FIG. In this embodiment, the electrical resistance of the composite film 1686 is measured by applying a voltage to the composite film 1686 and measuring the magnitude of the current flowing between the electrode 666 and the electrode 667 through the conductive filler 1688 in contact with each other. The value can be measured. The conductive filler only needs to have conductivity and corrosion resistance. For example, carbon-based conductive fillers such as carbon black, carbon fiber, carbon nanotube, and carbon nanohorn, metal fillers using noble metals such as gold and platinum, A filler using a metal compound such as TiC or a metal such as stainless steel plated with gold is used.

  FIG. 1A shows the state of the composite membrane 1686 when the fuel alcohol concentration is low, and FIG. 1B shows the state of the composite membrane 1686 when the fuel alcohol concentration is high. As described above, the polymer film 665 has a property of swelling as the alcohol concentration of the fuel increases. In the present embodiment, the polymer film 665 is used which has a property of swelling as the alcohol concentration of the fuel increases. For this reason, when the alcohol concentration of the fuel increases, the composite film 1686 including the polymer film 665 swells, and accordingly, the number density of the conductive filler 1688 per unit volume of the composite film 1686 decreases. Therefore, the distance between the conductive fillers 1688 existing in the composite film 1686 is increased, thereby reducing the number of electrical contact points between the conductive fillers 1688, and the first electrode terminal 666 and the second electrode terminal. The number of current paths to 667 is reduced. Therefore, when a current is passed through the composite film 1686, the electrical resistance value of the composite film 1686 increases. As a result, by measuring the electrical resistance value using the first electrode terminal 666 and the second electrode terminal 667, the change in the electrical resistance value of the composite film 1686 can be monitored, thereby measuring the alcohol concentration of the fuel. can do.

  Specific examples of the method for manufacturing the composite film 1686 include the following methods.

  A conductive filler is mixed and dispersed in the polymer solution to prepare a paste. At this time, the mixing and dispersibility of the conductive filler 1688 may be improved using a dispersion aid or the like. Next, the paste is cast on a glass plate and naturally dried at room temperature to produce a cast film. Further, the cast film is heat-treated to obtain a composite material of the conductive filler 1688 and the polymer material. Subsequently, the composite film 1686 can be manufactured by molding the composite material into a desired shape by cutting or the like.

  In the case of using heat-softening plastics, heat is applied to the plastics to soften them, and the conductive fillers 1688 are mixed and kneaded to mix and disperse the conductive fillers 1688 in the plastics. A composite material is obtained.

  Here, the content of the conductive filler 1688 in the composite film 1686 may be uniform or may have a composition gradient. Here, “having a composition gradient” means that the content of the conductive filler 1688 in the composite film 1686 is low on the upper side and higher on the lower side of the composite film 1686 shown in FIG. It refers to things.

  Here, due to the swelling of the polymer film 665, the number density of the conductive filler per unit volume of the composite film 1686 is reduced. However, within the range of the alcohol concentration used in the fuel cell, it is necessary to prevent the composite membrane 1686 from increasing as the electrical resistance value approaches infinity. As a countermeasure, for example, the material constituting the polymer film 665, the material constituting the conductive filler 1688, and the composite film 1686 so that the electric resistance value is below a certain value within the range of the alcohol concentration used in the fuel cell. It is preferable to select the content of the conductive filler 1688.

  Here, the desirable range of the mass content of the conductive filler 1688 in the composite film 1686 differs depending on the material used for the polymer film 665 and the material used for the conductive filler 1688. This is because the swelling rate due to alcohol differs depending on the material used for the polymer film 665. This is because there is a difference in the ease of electrical contact of the conductive filler 1688 in the composite film 1686 due to various factors such as the surface area per unit mass of the material used for the conductive filler 1688.

  For example, when a Nafion (registered trademark) solution (manufactured by DuPont) is used as the material of the polymer film 665 and a carbon-based material such as carbon black, carbon fiber, carbon nanotube, or carbon nanohorn is used as the conductive filler 1688, The conductive filler 1688 is preferably contained in an amount of 2% by mass to 30% by mass and preferably 5% by mass to 15% by mass with respect to the mass of the resin equivalent part of the Nafion (registered trademark) solution (manufactured by DuPont). More preferred. By setting the mass content of the carbon-based material within the above-described numerical range, a sensor 668 having suitable concentration measurement performance can be obtained. Moreover, when using metal materials, such as gold | metal | money and platinum, as the conductive filler 1688, the conductive filler 1688 is 20% by mass or more with respect to the mass of the resin equivalent part of the Nafion (registered trademark) solution (manufactured by DuPont). It is preferable to contain 80 mass% or less. By setting the mass content of the metal material within the above-described numerical range, a sensor 668 having suitable concentration measurement performance can be obtained.

  FIG. 2 is a diagram for explaining in detail the structure of the sensor 668 in the present embodiment. 2A is a diagram showing a surface of the sensor 668 on which the first electrode terminal 666 and the second electrode terminal 667 are provided, and FIG. 2B is a side view of FIG. 2A. is there. The first electrode terminal 666 and the second electrode terminal 667 can be made of any material that is stably present in the fuel and has conductivity. Here, the first electrode terminal 666 and the second electrode terminal 667 are sandwiched between two composite films 1686 and are thermocompression bonded. Two metal plates are joined to both ends of the composite film 1686, and the metal plates The first electrode terminal and the second electrode terminal can be attached to the composite film 1686 by a method of attaching to the composite film 1686 using a conductive paste or the like. As the conductive paste, a polymer paste containing a metal such as gold or silver, or a polymer paste such as acrylamide having a conductive property can be used. The first electrode terminal 666 and the second electrode terminal 667 are electrically connected to a signal processing unit 670 shown in FIG. 3 described later via a wiring 710a and a wiring 710b, respectively.

  FIG. 3 is a diagram illustrating an example of a configuration of a fuel cell system using the sensor according to the present embodiment. The fuel cell system 660 of FIG. 3 includes a fuel cell main body 100, a fuel electrode tank 662, a sensor 668 that is an alcohol concentration measurement device, a signal processing unit 670, a control unit 672, and a fuel supply adjustment unit that is a supply unit. 674, a pipe 124 for transporting liquid fuel, an auxiliary tank 676 which is a different concentration fuel storage unit and a container for storing liquid fuel, and a warning presentation unit 680.

  In the present embodiment, liquid fuel such as methanol, ethanol, dimethyl ether, or other alcohols can be used as the fuel. The liquid fuel can be an aqueous solution. In addition, an acid or an alkali can be added to the fuel. Thereby, the ion conductivity of hydrogen ion can be improved.

  The fuel cell main body 100 includes a solid electrolyte membrane 114 and a fuel electrode 102 and an oxidant electrode 108 disposed on the solid electrolyte membrane 114. As the oxidant supplied to the oxidant electrode 108, air can be normally used, but oxygen gas may be supplied. The detailed configuration of the fuel cell main body 100 will be described later.

  In the present embodiment, auxiliary tank 676 contains a fuel having a higher alcohol concentration than the fuel supplied to fuel electrode 102.

A sensor 668 that is an alcohol concentration measuring device is used to detect the alcohol concentration of the fuel in the fuel electrode tank 662. The sensor 668 includes a composite film 1686, a first electrode terminal 666 that is a pair of electrode terminals that are disposed on the composite film 1686 and measures the electrical resistance value of the composite film 1686, and a second electrode terminal 667. . Here, the composite film 1686 is a film in which a polymer film 665 (FIG. 1) whose dimensions change according to the alcohol concentration in the fuel and a conductive filler are mixed. Here, the conductive filler refers to particles, fibers, and the like such as conductive carbon, metal, and metal compounds, and has a resistivity of about 10 ⁹ Ω · cm or less. Further, as will be described later, the electrical resistance value of the composite film 1686 varies depending on the increase or decrease in the number of electrical contact points between the conductive fillers (the greater the number of electrical contact points, the lower the electrical resistance value). The measurement is performed by measuring the magnitude of the current flowing between the conductive fillers when a voltage is applied to the composite film 1686. Here, the voltage application unit and the current measurement unit are connected to the signal processing unit 670 in series. Further, it is also performed by measuring the magnitude of the voltage applied to the composite film 1686 when a current is passed between the conductive fillers.

  The first electrode terminal 666 and the second electrode terminal 667 can be made of any material as long as it has conductivity and is resistant to fuel. For example, gold, silver, platinum, It can be composed of aluminum, stainless steel, carbon or the like. The first electrode terminal 666 and the second electrode terminal 667 can be provided on the surface of the composite film 1686, but may be provided in the composite film 1686.

  The composite membrane 1686 is configured to impregnate the fuel in the fuel electrode tank 662, and the polymer membrane 665 (FIG. 1) is configured of a material that expands and contracts according to the alcohol concentration in the fuel. The fuel cell system 660 in the present embodiment detects the alcohol concentration of the fuel in the fuel electrode tank 662 based on the change in the electrical resistance value of the composite film 1686 due to the change in the volume of the polymer film 665 as described above. be able to.

  The polymer film 665 is made of a material that expands and contracts according to the alcohol concentration of the fuel, and can be made of a material that reversibly shrinks according to a change in concentration after the expansion. It can be made of the same material as the solid electrolyte membrane 114 of the main body 100. Here, examples of the material that expands and contracts according to the alcohol concentration of the fuel include those having a functional group with high alcohol affinity. Since these materials have high affinity for alcohol, alcohol, etc. It is considered that it has a property of expanding / contracting depending on the concentration of. Examples of such materials include those containing protonic acid groups whose swelling rate changes depending on the alcohol concentration, such as sulfonic acid groups, sulfoalkyl groups, sulfonimide groups, phosphoric acid groups, phosphinic acid groups, and phosphonic acid groups. Etc. can be used.

  Examples of the polymer of the target substrate to which proton acid groups such as sulfonic acid groups are bonded include polyether ketone, polyether ether ketone, polyether sulfone, polyether ether sulfone, polysulfone, polysulfide, polyphenylene, polyphenylene oxide, and polystyrene. A film made of polyimide, polybenzimidazole, polyamide, or the like can be used. Furthermore, an aromatic-containing polymer can also be used as the base polymer.

In addition, as the polymer of the target substrate to which the sulfonic acid group is bonded,
Resins having nitrogen or hydroxyl groups such as polybenzimidazole derivatives, polybenzoxazole derivatives, polyethyleneimine crosslinked products, polysilamine derivatives, amine-substituted polystyrenes such as polydiethylaminoethylstyrene, nitrogen-substituted polyacrylates such as polydiethylaminoethyl methacrylate;
Hydroxyl group-containing polyacrylic resin represented by silanol-containing polysiloxane and polyhydroxyethyl methacrylate;
Hydroxyl group-containing polystyrene resin represented by poly (p-hydroxystyrene);
Etc. can also be used.

  Hereinafter, as other polymer membranes having the property of expanding / contracting depending on the alcohol concentration, weakly acidic membranes such as perfluorocarboxylic acid membranes, fluorine having quaternary ammonium groups or various amines introduced as anion exchange groups Anion exchange membranes such as a system ion exchange membrane and an aminated styrene-divinylbenzene copolymer can also be used.

  In addition, a polymer having a crosslinkable substituent, for example, a vinyl group, an epoxy group, an acryl group, a methacryl group, a cinnamoyl group, a methylol group, an azide group, or a naphthoquinonediazide group, appropriately used for the above-described polymer. You can also. Moreover, what bridge | crosslinked these substituents can also be used.

Specifically, as the polymer film 665, for example,
Sulfonated polyetheretherketone;
Sulfonated polyethersulfone;
Sulfonated polyetherethersulfone;
Sulfonated polysulfone;
Sulfonated polysulfides;
Sulfonated polyphenylene;
Aromatic-containing polymers such as sulfonated poly (4-phenoxybenzoyl-1,4-phenylene) and alkylsulfonated polybenzimidazole;
Sulfoalkylated polyetheretherketone;
A sulfoalkylated polyethersulfone;
Sulfoalkylated polyetherethersulfone;
A sulfoalkylated polysulfone;
Sulfoalkylated polysulfides;
Sulfoalkylated polyphenylene;
Sulfonic acid group-containing perfluorocarbon (Nafion (manufactured by DuPont), Aciplex (manufactured by Asahi Kasei), etc.)
Carboxyl group-containing perfluorocarbon (Flemion (registered trademark) S membrane (Asahi Glass Co., Ltd.));
Copolymers such as a fluorine-containing polymer comprising a polystyrene sulfonic acid copolymer, a polyvinyl sulfonic acid copolymer, a crosslinked alkyl sulfonic acid derivative, a fluororesin skeleton and a sulfonic acid;
A copolymer obtained by copolymerizing acrylamides such as acrylamide-2-methylpropanesulfonic acid and acrylates such as n-butyl methacrylate;
Etc. can be used. Aromatic polyetheretherketone or aromatic polyetherketone can also be used.

  The first electrode terminal 666 and the second electrode terminal 667 are provided on the surface of the composite film 1686 or in the composite film 1686 so as to be separated from each other. Here, since the polymer film 665 is made of a material that expands and contracts in accordance with the alcohol concentration, the number density of the conductive filler 1688 in the composite film 1686 changes in accordance with the alcohol concentration. Therefore, the number of electrical contact points of the conductive filler 1688 included in the composite film 1686 changes according to the alcohol concentration of the fuel in the fuel electrode tank 662, and the first electrode terminal 666 and the second electrode terminal When a current is passed through the composite film 1686 between the first electrode terminal 666 and the second electrode terminal 667 according to the alcohol concentration of the fuel in the fuel tank 664, the composite film is measured. The electrical resistance value of 1686 changes. Here, in this embodiment, a direct current is used as a current that flows through the composite film 1686 between the first electrode terminal 666 and the second electrode terminal 667. Further, an alternating current may be used as a current flowing between the first electrode terminal 666 and the second electrode terminal 667.

  The alcohol concentration of the fuel in the fuel electrode tank 662 measured by the signal processing unit 670 is transmitted to the control unit 672. The fuel supply adjustment unit 674 performs a process of supplying fuel from the auxiliary tank 676 to the fuel electrode tank 662 via the pipe 124. When the control unit 672 determines that the alcohol concentration measured by the signal processing unit 670 is not within the proper range, the fuel supply adjustment unit 674 so that the alcohol concentration of the fuel in the fuel electrode tank 662 is within the proper range. Send an instruction signal to The fuel supply adjustment unit 674 controls the amount of fuel supplied from the auxiliary tank 676 to the fuel electrode tank 662 via the pipe 124 based on the control of the control unit 672.

  FIG. 11 is a diagram showing the configuration of the fuel supply adjusting unit 674 in detail. The fuel supply adjustment unit 674 includes a fuel supply unit 465. The fuel supply unit 465 changes the amount of fuel supplied from the auxiliary tank 676 to the fuel tank 664 via the pipe 124. As the fuel supply unit 465, a piezoelectric pump or the like can be used. When a piezoelectric pump is used as the fuel supply unit 465, the control unit 672 controls the amount of fuel supplied from the auxiliary tank 676 by changing the voltage applied to the piezoelectric pump.

  The signal processing unit 670 measures the alcohol concentration of the fuel in the fuel electrode tank 662 based on the resistance value of the composite film 1686 measured using the first electrode terminal 666 and the second electrode terminal 667.

  As shown in FIG. 12, the signal processing unit 670 includes a resistance measurement unit (R / O) 682 that measures a resistance value between the first electrode terminal 666 and the second electrode terminal 667, and a resistance measurement unit 682. Based on the measured resistance value, a concentration calculation unit (S / O) 684 that calculates the alcohol concentration in the fuel electrode tank 662, the resistance value between the first electrode terminal 666 and the second electrode terminal 667, and methanol. And a reference data storage unit 685 for storing reference data indicating the relationship with the density. As the resistance measuring unit 682, for example, a constant current source and a voltmeter, a constant voltage source and an ammeter, or the like can be used in direct current measurement. In the AC measurement, an AC voltage generator and a current measuring device can be used. The resistance value between the first electrode terminal 666 and the second electrode terminal 667 can be measured using a direct current or an alternating current. The concentration calculation unit 684 calculates the methanol concentration from the resistance value measured based on the reference data with reference to the reference data storage unit 685.

  Specifically, when the alcohol concentration in the fuel is lower than a certain reference value, the control unit 672 generates a warning in the warning presenting unit 680 and supplies high concentration methanol to the fuel electrode tank to the fuel supply adjustment unit 674. A command is issued to 662 to supply an amount that corrects the difference from the above-described reference value. If the alcohol concentration of the fuel is still lower than a certain reference value even after the supply, an even higher concentration of methanol is supplied. Command is made so that the alcohol concentration of the fuel falls within a certain reference value range.

  With the configuration as shown in the present embodiment, when the alcohol concentration of the fuel in the fuel electrode tank 662 is equal to or lower than the predetermined concentration, the warning presenting unit 680 generates a warning and the high-concentration methanol in the fuel Replenishment is automatically performed by the fuel supply amount determination method described above, and the fuel cell can be operated smoothly.

  In the present embodiment, the fuel supply amount determining method when the alcohol concentration of the fuel in the fuel electrode tank 662 is equal to or lower than the predetermined concentration has been described. However, the alcohol concentration of the fuel in the fuel electrode tank 662 is The fuel supply amount can also be adjusted when the concentration exceeds a predetermined concentration. For example, a method of reducing the replenishment amount of high-concentration methanol according to a command from the concentration detection unit, a separate low-concentration auxiliary tank or a pure water storage unit installed in the fuel cell system, and a signal processing unit. The method of replenishing low-concentration methanol and pure water by the command of this is mentioned.

  Further, the control unit 672 causes the warning presenting unit 680 to generate a warning when the alcohol concentration of the fuel in the fuel electrode tank 662 does not fall within an appropriate range even after the process of controlling the fuel supply adjusting unit 674 is repeated.

  Further, as shown in FIG. 9, the sensor 668 may have a configuration in which the surfaces of the first electrode terminal 666 and the second electrode terminal 667 are covered with a hydrophobic film 720 such as Teflon (registered trademark). . In this way, even when the sensor 668 is introduced into the fuel electrode tank 662, the first electrode terminal 666 and the second electrode terminal 667 do not come into direct contact with the fuel in the fuel electrode tank 662. Therefore, the first electrode terminal 666 and the second electrode terminal 667 can be prevented from being corroded by the fuel. Thereby, the 1st electrode terminal 666 and the 2nd electrode terminal 667 can be kept stable. Therefore, the stability of the sensor 668 can be improved.

  FIG. 4 is a diagram illustrating another example of the sensor 668. As illustrated in FIG. 4, both ends of the composite film 1686 may be sandwiched between a first electrode terminal 666 and a second electrode terminal 667. Here, the lead wire 710 a is connected to the first electrode terminal 666, and the lead wire 710 b is connected to the second electrode terminal 667. As a sandwiching form, the first electrode terminal 666 is joined in a U-shaped cross section so as to cover one side of the composite film 1686 shown in FIG. 4 and covers the other side of the three sides. In addition, like the form in which the second electrode terminal 667 is joined in a U-shaped cross section, a part of the composite film 1686 is covered with the first electrode terminal 666 and the second electrode terminal 667. By doing so, the composite film 1686 can be stably fixed. Therefore, the stability of the sensor 668 can be improved. At this time, the first electrode terminal 666 and the second electrode terminal 667 may be fixed to an insulating support.

  Further, in the sensor 668 in FIG. 4, instead of using the lead wires 710a and 710b, wiring is provided on a substrate (not shown) provided with wiring, and the first electrode terminal 666 and the second electrode are not used without using the lead wire. The electrode terminal 667 may be electrically connected to the signal processing unit 670 or the like. As a substrate for wiring, a material having insulating properties and excellent mechanical strength and chemical stability is used, and a ceramic substrate such as alumina or a glass substrate is particularly preferably used. Further, by introducing a polymer porous substrate or the like in the surface of the composite film 1686 and suppressing excessive swelling or irreversible swelling in the surface of the composite film 1686, the mechanical strength of the sensor 668 is further increased. And the measurement accuracy of the sensor 668 can be increased.

  FIG. 5 is a diagram illustrating another example of the sensor 668. As illustrated in FIG. 5, a composite film 1686 may be provided over the substrate 202 over which the first electrode terminal 666 and the second electrode terminal 667 are arranged. As a method for providing the composite film 1686 on the substrate 202, for example, a method in which the composite film 1686 is manufactured and then cut to an appropriate size and then bonded onto the substrate 202 can be used. Here, for bonding the composite film 1686 onto the substrate 202, a mixed solution of a conductive filler and a polymer solution used for the composite film 1686 is applied to the surface of the substrate 202 in advance, and then the composite film 1686 is applied to the substrate 202. A method such as thermocompression bonding can be used. Further, the adhesion between the substrate 202 and the composite film 1686 can be improved by applying the mixed solution after the surface of the substrate 202 is roughened. Further, the composite film 1686 may be provided over the substrate 202 by a dip coating method, a casting method, a spin coating method, or the like. By using such a method, a submicron order thin film can be easily formed, and the sensor 668 can be miniaturized.

  FIG. 6 is a diagram showing a modification of the sensor 668 shown in FIG. FIG. 6A is a diagram of a sensor in which a pressing plate 1694 having a fuel absorbing portion 1690 and a hole 1692 through which fuel passes is provided in the sensor 668 shown in FIG. FIG. 6B is a view of the pressing plate 1694 viewed from the top. As a material constituting the fuel absorbing portion 1690, a flexible polymer porous body that easily absorbs fuel can be used, and specifically, cellulose, polyurethane, or the like can be used. The sensor 668 is provided with a fuel absorbing portion 1690 and a pressing plate 1694, and the fuel absorbing portion 1690 is made of a flexible porous material. Since a force that presses the composite film 1686 toward the substrate 202 side to the extent that the composite film 1686 does not expand outside the pressing plate 1694 is exerted, the adhesion between the composite film 1686 and the substrate 202 when the composite film 1686 contracts can be enhanced. . Accordingly, the resistance of the sensor 668 to external forces such as impact and vibration can be increased, and the measurement accuracy of the sensor 668 can be increased.

  FIG. 7 is a diagram illustrating another example of the sensor 668. In the sensor 668 shown in FIG. 7, a first electrode terminal 666 and a second electrode terminal 667 are formed on the surface of the substrate 202, and a part of the first electrode terminal 666 and the second electrode terminal 667 is a composite film. The sensor shown in FIG. 4 is different from the sensor shown in FIG. With the sensor 668 having such a structure, a part of the first electrode terminal 666 and the second electrode terminal 667 does not directly contact the fuel but contacts the fuel through the composite film 1686. Become. Therefore, portions of the first electrode terminal 666 and the second electrode terminal 667 embedded in the composite film 1686 can be made less susceptible to the influence of corrosion or the like due to fuel. Thereby, the part embedded in the composite film 1686 among the 1st electrode terminal 666 and the 2nd electrode terminal 667 can be kept stable. Therefore, the stability of the sensor 668 can be improved. In addition, since the wirings 710 a and 710 b provided on the first electrode terminal 666 and the second electrode terminal 667 are attached to one surface side of the sensor 668, the wiring is attached to both surface sides of the sensor 668. The structure of the sensor 668 can be further simplified as compared with the case where the sensor is provided.

  FIG. 8 is a diagram illustrating another example of the sensor 668. As illustrated in FIG. 8, the first electrode terminal 666 and the second electrode terminal 667 can be provided in the thickness direction of the composite film 1686. When the sensor 668 has such a configuration, the composite film 1686 is constrained and therefore does not expand beyond a predetermined volume. With the sensor 668 having such a structure, an increase in the resistance value of the sensor 668 itself can be suppressed. Therefore, when the alcohol concentration of the fuel 124 is measured using the sensor 668, the voltage applied to the first electrode terminal 666 and the second electrode terminal 667 constituting the sensor 668 can be lowered. Therefore, the fuel cell system 660 can be a power-saving system. Further, as a material constituting the first electrode terminal 666 and the second electrode terminal 667, a porous material such as a nickel porous plate can be used. In this way, the solution containing the fuel can be easily diffused into the composite membrane 1686. Further, in order to suppress swelling of the composite film 1686 in the film surface direction which is the vertical direction in FIG. 8, one or more porous polymer base materials such as PTFE may be provided in the film surface direction. By doing so, the mechanical strength of the sensor 668 can be further increased.

  The sensor 668 according to this embodiment has been described above. Hereinafter, an example of a fuel cell system using the sensor 668 according to the present embodiment will be described.

  FIG. 10 is a diagram illustrating another example of the configuration of the fuel cell system 660. As shown in FIG. 10, a fuel tank 664 may be provided in the fuel cell system 660 and a sensor 668 may be installed in the fuel tank 664. In this case, the fuel supplied to the fuel electrode tank 662 is introduced into the fuel tank 664. A fuel tank 664 is provided in the fuel cell system 660, and the alcohol concentration in the fuel tank 664 is adjusted by measuring the alcohol concentration in the fuel tank 664 by using the sensor 668, whereby the fuel electrode tank used for direct power generation. The range of increase or decrease of the alcohol concentration in 662 can be relaxed.

  The fuel cell system 660 may not include the auxiliary tank 676 and the fuel supply adjustment unit 674. In this case, if the alcohol concentration measured by the signal processing unit 670 is not within an appropriate range, the control unit 672 causes the warning presenting unit 680 to generate a warning. When the fuel 124 in the fuel tank 664 is circulated to the fuel electrode tank 662 to cause an electrochemical reaction in the fuel cell main body 100, the alcohol content (molar ratio) in the fuel is usually the water content (molar ratio). ), The alcohol in the fuel is consumed, and the alcohol concentration of the fuel in the fuel tank 664 gradually decreases. With such a configuration, when the alcohol concentration of the fuel in the fuel tank 664 becomes a predetermined concentration or less, a warning can be generated in the warning presentation unit 680, and the end point where the fuel in the fuel tank 664 can be used is detected. can do.

  The fuel cell system 660 may further include a temperature sensor. That is, the temperature dependence of the sensor 668 may be compensated by further including a temperature sensor. The temperature sensor measures the temperature of the fuel in the fuel tank 664. The reference data storage unit 685 (FIG. 12) can store the relationship between the resistance value between the first electrode terminal 666 and the second electrode terminal 667 and the methanol concentration for each temperature. Further, the reference data storage unit 685 can store a correction formula for the relationship between the resistance value between the first electrode terminal 666 and the second electrode terminal 667 and the methanol concentration for each temperature. In this way, the signal processing unit 670 can measure the methanol concentration in the fuel in consideration of the temperature of the fuel in the fuel tank 664, and can measure the methanol concentration more accurately.

  As the temperature sensor, a thermocouple, a metal resistance temperature detector, a thermistor, an IC temperature sensor, a magnetic temperature sensor, a thermopile, a pyroelectric temperature sensor, or the like can be used.

  The sensor 668 may be provided on the wall of the fuel tank 664.

  Next, the configuration of the fuel cell main body 100 shown in FIG. 3 will be described with reference to FIG. The fuel cell main body 100 has one or a plurality of single cell structures 101. FIG. 13 is a cross-sectional view schematically showing the single cell structure 101. Each single cell structure 101 includes a fuel electrode 102, an oxidant electrode 108 and a solid electrolyte membrane 114. In the fuel cell main body 100, the fuel is supplied to the fuel electrode 102 of the single cell structure 101 via the fuel electrode side separator 120. Further, the oxidant 126 is supplied to the oxidant electrode 108 of each single cell structure 101 via the oxidant electrode side separator 122.

  The solid electrolyte membrane 114 has a role of separating the fuel electrode 102 and the oxidant electrode 108 and moving hydrogen ions between them. For this reason, the solid electrolyte membrane 114 is preferably a membrane having high hydrogen ion conductivity. Further, it is preferably chemically stable and has high mechanical strength.

  The fuel electrode 102 and the oxidant electrode 108 respectively form a fuel electrode side catalyst layer 106 and an oxidant electrode side catalyst layer 112 containing carbon particles carrying a catalyst and solid electrolyte fine particles on the substrate 104 and the substrate 110, respectively. It is good also as a structure. Examples of the catalyst include platinum and an alloy of platinum and ruthenium. The catalyst for the fuel electrode 102 and the oxidant electrode 108 may be the same or different.

  By stacking the single cell structures 101 configured as described above, a fuel cell main body 100 including a fuel cell stack in which a plurality of single cell structures 101 are connected in series can be obtained.

  Hereinafter, effects of the sensor 668 and the fuel cell system 660 according to the present embodiment will be described.

The polymer film 665 constituting the composite film 1686 of the sensor 668 in the present embodiment has a property that the swelling rate changes with a change in the alcohol concentration of the fuel. Further, in the present embodiment, the polymer film 665 having the property that the swelling rate increases as the alcohol concentration of the fuel increases. For this reason, when the alcohol concentration of the fuel increases, the swelling rate of the composite film 1686 including the polymer film 665 increases, and accordingly, the number density of the conductive fillers 1688 per unit volume of the composite film 1686 decreases. Therefore, when the distance between the conductive fillers 1688 existing in the composite film 1686 is increased, the number of electrical contact points between the conductive fillers is reduced, and the first electrode terminal 666 and the second electrode terminal are reduced. The number of current paths to 667 is reduced. Accordingly, the electrical resistance value of the composite film 1686 when a current is passed through the composite film 1686 increases. As a result, by measuring the electric resistance value using the first electrode terminal 666 and the second electrode terminal 667, by monitoring the change in the electric resistance value of the composite film 1686, the alcohol concentration of the fuel can be accurately determined. Can be measured.
Moreover, since the decrease in the number of current paths is not easily affected by the pH of the fuel, the pH dependence when measuring the alcohol concentration can be reduced to a level that can be ignored.

  Further, by using the sensor 668 in the fuel cell system 660, a simplified fuel cell system 660 that consumes less power and consumes less fuel than a sensor having a fuel cell configuration can be realized. Further, the sensor 668 provided in the fuel cell system 660 can use a direct current power source to measure the electric resistance value of the composite film 1686. For this reason, the alcohol concentration of the fuel can be measured using the sensor 668 without providing a DC / AC conversion circuit in the fuel cell system 660. Therefore, a fuel cell system 660 that is smaller, lighter, and simplified can be realized. Furthermore, since the sensor 668 having high fuel measurement accuracy is provided, it is possible to realize a fuel cell system 660 that is excellent in controllability of fuel concentration and can easily grasp the replacement time of the auxiliary tank 676 and the like.

  Further, according to the present embodiment, the fuel can be obtained with a simple configuration in which the first electrode terminal 666 and the second electrode terminal 667 are attached to the composite film 1686 composed of the polymer film 665 and the conductive filler 1688. The fuel cell system 660 using the sensor 668 that can detect the methanol concentration of the fuel can be realized.

Second Embodiment FIG. 14 is a diagram illustrating an example of a configuration of a fuel cell system according to the present embodiment. In the present embodiment, a cartridge 678 is attached to the fuel cell system 660.

  The cartridge 678 is configured to include a fuel tank 664 and an auxiliary tank 676. On the main body side 679 of the fuel cell system 660, a fuel cell main body 100, a fuel electrode tank 662, a fuel supply adjusting unit 674, a signal processing unit 670, a control unit 672, and a warning presenting unit 680 are provided. Constituent elements similar to those described in the first embodiment are denoted by the same reference numerals, and description thereof is omitted as appropriate.

  Here, the fuel supply adjusting unit 674 is configured to be able to supply the fuel 124 contained in the auxiliary tank 676 of the cartridge 678 to the fuel tank 664 when the cartridge 678 is attached. In cartridge 678, fuel tank 664 includes a sensor 668. On the main body side 679, the signal processing unit 670 has terminals (not shown) that are electrically connected to the first electrode terminal 666 and the second electrode terminal 667 of the sensor 668 when the cartridge 678 is attached. Provided. The fuel electrode tank 662 is configured to be able to introduce fuel from the fuel tank 664.

  FIG. 15 is a schematic diagram showing a fuel tank 664 in the cartridge 678 and a fuel electrode tank 662 on the main body side 679. A fuel supply port 643 is provided in the fuel electrode tank 662, and the fuel tank 664 has a fitting portion 647 that fits into the fuel supply port 643 of the fuel electrode tank 662. On the side wall of the cartridge body 645, an electrode terminal 666a and an electrode terminal 667a that are electrically connected to the first electrode terminal 666 and the second electrode terminal 667 of the sensor 668, respectively, are provided. Here, the fuel cell main body 100 further includes an insulating sheet 130, a fuel electrode side current collector 132, and an oxidant electrode side current collector 134 in addition to the configuration shown in FIG. 14.

  Also in the form in which the cartridge 678 is attached to the fuel cell system 660, the sensor 668 may be provided in the fuel electrode tank 662 on the main body side 679. Further, the fuel cell system 660 may be configured such that the cartridge 678 including only the auxiliary tank 676 is removable. Although not shown, the cartridge 678 may include a valve. In addition, the sensor 668 can be provided on the wall portion of the cartridge 678. In this case, the sensor 668 exposed outside the cartridge 678 can be covered with a seal or the like, and the seal can be removed before being attached to the main body side 679. Thereby, it is possible to prevent liquid fuel from leaking from the cartridge 678 before the cartridge 678 is attached to the main body side 679.

  Further, the fuel tank 664 of the cartridge 678 may include a fuel supply member. In this example, the fuel cell main body 100 is not provided with the fuel electrode tank 662, and the fuel contained in the fuel tank 664 is supplied to the fuel electrode 102 of the fuel cell main body 100 via the fuel supply member. The fuel supply member is made of a material that can absorb the fuel and supply the absorbed fuel to the fuel cell main body 100. The fuel supply member can be made of urethane, for example. In addition, the fuel supply member can be composed of a ceramic porous body such as a silica porous body or an alumina porous body, a porous film such as a fluororesin, polyethylene, polypropylene, polycarbonate, polyimide, polysulfone, polysulfide, or polybenzimidazole. .

  When the cartridge 678 has such a configuration, the control unit 672 may cause the warning presenting unit 680 to generate a warning when the alcohol concentration in the fuel tank 664 measured by the signal processing unit 670 is not within an appropriate range. it can.

  According to fuel cell system 660 in the present embodiment, the alcohol concentration of fuel can be detected with a simple structure.

  The present invention has been described based on the embodiments. This embodiment is an exemplification, and it will be understood by those skilled in the art that various modifications can be made to combinations of the respective constituent elements and processing processes, and such modifications are within the scope of the present invention. is there.

  For example, the sensor 668 may include three or more electrode terminals, for example, four electrode terminals. When the sensor 668 includes four electrode terminals, one pair of electrode terminals may be used for connecting a constant current source, and the other pair of electrode terminals may be used for voltage measurement. By doing so, almost no current flows through the voltage measurement terminal, so that the influence of the contact resistance between the composite film 1686 as the measurement object and the voltage measurement electrode terminal is negligibly small. The alcohol concentration can be measured with higher accuracy. One pair of electrode terminals may be used for voltage application, and the other pair of electrode terminals may be used for current measurement.

  The sensor 668 may be used to measure the alcohol concentration before reforming in a fuel cell system that reforms methanol or the like into hydrogen gas and uses hydrogen as a fuel.

  Further, the sensor 668 is not limited to the alcohol concentration measurement in the fuel cell system 660, and may be used to measure the alcohol concentration in various solutions. For example, it may be used to measure the alcohol concentration in an alcoholic beverage.

  Further, the fuel cell system 660 can be modified. For example, the fuel cell system 660 may include two auxiliary tanks and two fuel supply units. In this case, fuel cell system 660 includes a first auxiliary tank and a second auxiliary tank in place of auxiliary tank 676 shown in FIG. The first fuel component and the second fuel component supplied from the first auxiliary tank and the second auxiliary tank are mixed in the mixing unit and supplied to the fuel cell main body as fuel.

  The fuel cell system 660 may further include a concentration adjustment unit. The concentration adjusting unit adjusts the mixing unit to control the mixing ratio of the first fuel component and the second fuel component supplied from the first auxiliary tank and the second auxiliary tank, respectively. The density adjusting unit is controlled by the control unit.

  In this way, in the fuel supply adjustment unit, the supply amounts of the two fuel components are individually controlled, so that the fuel concentration can be adjusted as appropriate. Further, since the two fuel components are mixed in the mixing unit and supplied to the fuel cell main body, the two fuel components can be uniformly mixed and supplied to the fuel cell main body.

  Note that the fuel supply adjustment unit may include three or more fuel supply units. In this case, the fuel cell system may also include three or more auxiliary tanks.

  In the fuel cell system 660, the cartridge 678 may include a first auxiliary tank and a second auxiliary tank that stores fuel having a different alcohol concentration from the first auxiliary tank. Note that either one of the first auxiliary tank and the second auxiliary tank may contain water that does not contain alcohol. Further, after the fuel is supplied to the fuel cell main body 100, the discharged water may be returned to either the first auxiliary tank or the second auxiliary tank and circulated.

  Here, the main body side 679 may be provided with a first pump and a second pump. By driving the first pump and the second pump, fuel can be supplied to the main body side 679 from the first auxiliary tank and the second auxiliary tank. The sensor 668 may be provided in the fuel electrode tank 662, or may be provided in a pipe connecting the fuel tank 664 and the fuel electrode tank 662, and the first pump, the second pump, and the fuel. It may be provided in a pipe connecting the tank 664.

  Further, the first pump and the second pump may be provided in the cartridge 678. Also in this case, the first pump and the second pump may be configured to be electrically connected to the control unit 672 (see FIG. 14 and the like) when the cartridge 678 is attached to the main body side 679. Well, it can be controlled by the controller 672.

  Although an example in which the fuel tank 664 is provided on the main body side 679 is shown, the fuel cell system 660 may not include the fuel tank 664, and the fuel supplied from the cartridge 678 is connected to the fuel electrode via a pipe. It is good also as a form introduced directly into the tank 662.

  In the above-described embodiment, the form of measuring the alcohol concentration using the sensor 668 has been described. For example, the concentration of a predetermined component in a solution other than alcohol, such as formaldehyde, acetone, formic acid, or the like, is measured using the sensor. May be.

  Moreover, in the said embodiment, although the form which measures alcohol concentration using the sensor 668 which has the polymer film 665 which swells as alcohol concentration becomes high was demonstrated, in solutions other than alcohol, such as formaldehyde, acetone, formic acid, etc. The concentration of the predetermined component can also be measured by using what is exemplified as the polymer film 665. For example, by making a sensor containing a polymer film containing a sulfonic acid group, a sulfoalkyl group, a sulfonimide group, a phosphoric acid group, a phosphinic acid group, a phosphonic acid group, etc. that swells as the concentration of formic acid increases, Measurement of the above components becomes possible.

Example 1
Nafion solution (registered trademark) DE2020 (manufactured by DuPont; resin content 20%) is used as the polymer solution, and carbon black is used as the conductive filler relative to the resin equivalent of Nafion solution (registered trademark) DE2020 (manufactured by DuPont). Thus, a paste in which 11% by mass is mixed and dispersed is prepared. Next, the paste is cast on a glass plate and naturally dried at room temperature to produce a cast film. Furthermore, a composite material of a conductive filler and a polymer material can be obtained by heat-treating the cast film at a temperature of 140 ° C. Next, the composite material is cut into a size of about 9 mm in width, about 7 mm in length, and about 0.6 mm in thickness to produce a composite film. Subsequently, using two composite films, two platinum terminals (diameter: about 0.2 mm, length: about 20 mm) are sandwiched at intervals of 6 mm, and two platinum terminals are formed by thermocompression bonding in the thickness direction. The sensor is prepared by attaching to the composite membrane.

  A resistance value between the electrode terminals of the sensor was measured by introducing a methanol aqueous solution having a known concentration into the container and flowing a direct current. Table 1 is a table showing the methanol concentration and electrical resistance data, and FIG. 16 is a diagram showing the relationship between the methanol concentration and the electrical resistance value. As shown in FIG. 16, by using the above sensor, the alcohol concentration could be detected with high accuracy. Moreover, the alcohol concentration could be repeatedly measured using the sensor.

Example 2
Using the sensor produced in Example 1, an aqueous solution having a methanol concentration of 5% by mass was introduced into the container, and 0.5 mol / l sulfuric acid was dropped into the aqueous solution having a pH of 6.4 to change the pH of the aqueous solution. The resistance value between the electrode terminals of the sensor was measured. Table 2 is a table showing data on pH and electrical resistance when the methanol concentration is 5% by mass. According to this result, even if the pH is changed from 6.4 to 2.7, the electric It was found that the resistance value hardly changed. As shown in Table 2, it was found that the alcohol concentration can be accurately measured by using the sensor.

Example 3
Nafion solution (registered trademark) DE2020 (manufactured by DuPont; resin content 20%) is used as the polymer solution, and carbon black is used as the conductive filler relative to the resin equivalent of Nafion solution (registered trademark) DE2020 (manufactured by DuPont). Thus, a paste in which 13% by mass is mixed and dispersed is prepared. Next, the paste is cast on a glass plate and naturally dried at room temperature to produce a cast film. Furthermore, a composite material of a conductive filler and a polymer material can be obtained by heat-treating the cast film at a temperature of 140 ° C. Next, the composite material is cut into a size of about 3.5 mm in width, about 15 mm in length, and about 0.2 mm in thickness to produce a composite film. Subsequently, the composite membrane is held by two platinum terminals (width: about 3.5 mm, length: 2.5 mm, thickness: 0.1 mm), and the two platinum terminals are attached to the composite membrane at intervals of 10 mm, thereby Prepare.

  Acetone aqueous solution having a known concentration was introduced into the container, and a direct current was passed to measure the resistance value between the electrode terminals of the sensor. Table 3 is a table showing the acetone concentration and electrical resistance data, and FIG. 17 is a diagram showing the relationship between the acetone concentration and the electrical resistance value. As shown in Table 3 and FIG. 17, by using the sensor, the acetone concentration could be detected with high accuracy.

Example 4
Using the sensor produced in Example 3, a formic acid aqueous solution having a known concentration was introduced into the container, and a resistance value between the electrode terminals of the sensor was measured by flowing a direct current. Table 4 is a table showing formic acid concentration and electrical resistance data, and FIG. 18 is a diagram showing the relationship between formic acid concentration and electrical resistance value. As shown in Table 4 and FIG. 18, by using the sensor, the formic acid concentration could be detected with high accuracy.

It is a figure which shows the sensor which concerns on embodiment in detail. It is a figure which shows the other example of the sensor which concerns on embodiment. It is a figure which shows an example of a structure of the fuel cell system which concerns on embodiment. It is a figure which shows the other example of a sensor. It is a figure which shows the other example of a sensor. It is a figure which shows the other example of a sensor. It is a figure which shows the other example of a sensor. It is a figure which shows the other example of a sensor. It is a figure which shows the other example of a sensor. It is a figure which shows the other example of a structure of the fuel cell system which concerns on embodiment. It is a figure which shows the structure of the fuel supply process part shown in FIG. 3 in detail. It is a figure which shows the structure of the signal processing part shown in FIG. 3 in detail. It is sectional drawing which showed typically the single cell structure of the fuel cell main body which concerns on embodiment. It is a figure which shows an example of a structure of the fuel cell system which concerns on embodiment. It is a schematic diagram which shows the fuel tank in the cartridge shown in FIG. 14, and the fuel electrode tank in a main body side. It is a figure which shows the relationship between the methanol concentration which concerns on an Example, and an electrical resistance value. It is a figure which shows the relationship between the acetone density | concentration which concerns on an Example, and an electrical resistance value. It is a figure which shows the relationship between the formic acid which concerns on an Example, and an electrical resistance value.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Fuel cell main body 101 Single cell structure 102 Fuel electrode 104 Base body 106 Fuel electrode side catalyst layer 108 Oxidant electrode 110 Base body 112 Oxidant electrode side catalyst layer 114 Solid electrolyte membrane 120 Fuel electrode side separator 122 Oxidant electrode side separator 124 Pipe 126 Oxidant 130 Insulating sheet 132 Fuel electrode side current collector 134 Oxidant electrode side current collector 202 Substrate 465 Fuel supply part 643 Fuel supply port 645 Cartridge body 647 Fitting part 660 Fuel cell system 662 Fuel electrode tank 664 Fuel tank 665 High Molecular film 666 First electrode terminal 667 Second electrode terminal 668 Sensor 670 Signal processing unit 672 Control unit 674 Fuel supply adjustment unit 676 Auxiliary tank 678 Cartridge 679 Main body side 680 Warning presentation unit 682 Resistance measurement unit 684 Concentration calculation unit 685 Irradiation data storage unit 720 film 851 fuel tank 1686 composite film 1688 electrically conductive filler 1690 fuel absorbing section 1692 holes 1694 pressing plate

Claims (10)

A polymer film that changes dimensions according to the concentration of the predetermined component in the liquid when immersed in the liquid containing the predetermined component;
A conductive filler mixed in the polymer film;
At least a pair of electrode terminals disposed on the polymer film;
A solution concentration measuring device comprising: The solution concentration measuring device according to claim 1,
The solution concentration measuring device, wherein the polymer membrane contains a sulfonic acid group. In the solution concentration measuring device according to claim 1 or 2,
The solution concentration measuring apparatus, wherein the conductive filler is a conductive filler containing carbon as a main component. In the solution concentration measuring device according to claim 1 or 2,
The solution concentration measuring apparatus, wherein the conductive filler is carbon black. In the solution concentration measuring device according to claim 1 or 2,
The solution concentration measuring device, wherein the conductive filler is a metal filler. In the solution concentration measuring device according to claim 1 or 2,
The solution concentration measuring apparatus, wherein the conductive filler is a filler using a metal compound. In the solution concentration measuring device according to any one of claims 1 to 6,
The solution concentration measuring apparatus, wherein the predetermined component is alcohol.   A fuel container for a fuel cell, comprising the solution concentration measuring device according to claim 1. A fuel cell system using a liquid fuel containing alcohol,
A fuel cell main body including a solid polymer electrolyte membrane, and a fuel electrode and an oxidizer electrode disposed on the solid polymer electrolyte membrane;
A container containing the liquid fuel;
(A) a polymer film that changes dimensions according to the concentration of the predetermined component in the liquid when immersed in a liquid fuel containing the predetermined component;
A fuel comprising: (b) a conductive filler mixed with the polymer film; and (c) a solution concentration measuring device for a fuel cell including at least a pair of electrode terminals disposed on the polymer film. Battery system. The fuel cell system according to claim 9, wherein
The fuel cell system further comprising a signal processing unit for detecting the concentration of the predetermined component measured using the solution concentration measuring device for a fuel cell.

Images