JP2006156034A - Liquid fuel battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small and thin liquid fuel cell in which reduction of assembly man-hour and simplification of assembly work are realized, and of which productivity is high. <P>SOLUTION: In the liquid fuel cell, a plurality of electrode and electrolyte assemblies 1 are arranged between a pair of substrates 3a, 3b, and current collectors 5a, 5b which electrically contact with the electrode and electrolyte assemblies 1 are arranged on a part of the surface of the substrates 3a, 3b. The plurality of electrode and electrolyte assemblies 1 are electrically connected by the current collectors 5a, 5b. The substrate 3b has a recessed part 9 and the substrate 3a has a projected part 8, and the pair of substrates 3a, 3b are mutually engaged by the recessed part 9 and the projected part 8. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a liquid fuel cell in which a plurality of single cells are arranged on a plane.

  In recent years, with the widespread use of cordless devices such as personal computers and mobile phones, secondary batteries as power sources are increasingly required to be smaller and have higher capacities. Currently, lithium ion secondary batteries have been put into practical use as secondary batteries that have high energy density and can be reduced in size and weight, and demand for mobile device power supplies is increasing. However, depending on the type of cordless device used, this lithium secondary battery has not yet reached a level that guarantees sufficient continuous use time.

  Under such circumstances, solid polymer fuel cells that use solid polymer electrolytes as electrolytes, oxygen in the air as positive electrode active materials, and hydrogen, methanol, etc. as negative electrode active materials are available as batteries that can meet the above-mentioned demands. Attention has been paid to the fact that a higher energy density can be expected than lithium ion secondary batteries. In particular, direct methanol fuel cells that use methanol, which is a liquid fuel, for direct cell reactions do not require the use of a blower that supplies air to the cell body or a pump that supplies fuel. Therefore, it is promising as a future portable power supply (see, for example, Patent Document 1).

Recently, a liquid fuel cell in which a plurality of unit cells are arranged on the same plane and connected to collect current to reduce the thickness has been proposed (for example, Patent Document 2, Patent Document 3, Patent Document). 4. See Patent Document 5.)
JP 2000-268836 A JP 2004-103262 A Japanese Patent Laid-Open No. 2004-14148 JP 2003-323902 A JP 2003-282131 A

  However, when collecting current by connecting adjacent unit cells, the structure becomes complicated, and a large space only for connection that does not contribute to battery performance is required. In addition, in order to efficiently arrange adjacent cells on a flat surface while ensuring insulation, a pair of current collector plates on both sides of an electrode / electrolyte integrated body consisting of a positive electrode, a negative electrode, and a solid electrolyte is accurately provided. In addition to aligning and arranging, it is necessary to accurately align and arrange adjacent current collector plates.

  For example, in the current collection method described in Patent Document 2 or Patent Document 3, a plurality of electrode / electrolyte integrated products that are power generation elements are arranged in a plane, and the electrode / electrolyte integrated material is sandwiched between a pair of current collector plates. Although current collection is performed, it is necessary to align the positions of the pair of current collector plates and the positions of adjacent current collector plates with respect to the electrode / electrolyte integrated body, which makes assembly difficult.

  In addition, the current collecting method described in Patent Document 4 arranges a plurality of electrode / electrolyte integrals, which are power generation elements, in a flat shape, and then attaches the adapter / electrolyte integral to the adapter unit to collect current. Similarly, it is necessary to align the positions of the pair of current collector plates and the adjacent current collector plates with respect to the electrode / electrolyte integrated body, which is difficult to assemble.

  Furthermore, like the current collection method described in Patent Document 5, there are a method of bending and mounting the current collector plate and a method of joining adjacent current collector plate lead parts by welding or the like. A lamination process is required, and there is a problem that productivity is lowered.

  Therefore, the present invention solves the above-described problems, and provides a highly productive liquid fuel cell by improving the structure of a liquid fuel cell in which a plurality of single cells are arranged on a plane.

  The liquid fuel cell of the present invention is a liquid fuel cell including a positive electrode for reducing oxygen, a negative electrode for oxidizing fuel, a solid electrolyte disposed between the positive electrode and the negative electrode, and a liquid fuel storage unit. The positive electrode, the negative electrode, and the solid electrolyte constitute an electrode / electrolyte integrated product, and a plurality of the electrode / electrolyte integrated products are arranged between a pair of substrates, and a part of the surface of the substrate Is provided with a current collector that is in electrical contact with the electrode / electrolyte integral, the plurality of electrodes / electrolyte integral is electrically connected by the current collector, and one of the substrates is a recess. The other of the substrates includes a convex portion, and the pair of substrates are fitted to each other by the concave portion and the convex portion.

  INDUSTRIAL APPLICABILITY The present invention can reduce the number of assembling steps for a small and thin liquid fuel cell and simplify the assembling work, and can provide a highly productive liquid fuel cell.

  An example of the liquid fuel cell of the present invention includes a positive electrode that reduces oxygen, a negative electrode that oxidizes fuel, a solid electrolyte disposed between the positive electrode and the negative electrode, and a liquid fuel storage unit. The solid electrolyte constitutes an electrode / electrolyte integrated product, and a plurality of these electrode / electrolyte integrated products are arranged between a pair of substrates. A current collector that is in electrical contact with the electrode / electrolyte integrated product is disposed on a part of the surface of the substrate, and the plurality of electrode / electrolyte integrated products are electrically connected by the current collector. By preliminarily arranging the current collecting part on the board, it is not necessary to align the board and the current collecting part when assembling the battery, so that the number of parts can be reduced and the number of assembly steps can be reduced.

  One of the substrates includes a concave portion, the other of the substrates includes a convex portion, and the pair of substrates are fitted to each other by the concave portion and the convex portion. As a result, the substrates can be reliably bonded to each other and the assembly work can be simplified.

  It is preferable that the said current collection part is formed from the metal thin film. Thereby, a liquid fuel cell can be formed more thinly.

  The metal thin film is preferably formed of at least one selected from the group consisting of copper plating, gold plating, silver plating, and solder plating. This is because these platings have high conductivity.

  The plating thickness is preferably 1 μm or more and 200 μm or less. Within this range, even if corrosion occurs on the plating surface due to liquid fuel or the like, conductivity can be ensured and the plating material is not excessively used.

  The substrate is preferably formed of at least one resin selected from the group consisting of glass-filled epoxy resin, polytetrafluoroethylene, hard polyvinyl chloride, polypropylene, and polyethylene. Since these resins have high rigidity, the substrates can be firmly bonded to each other. As a result, the adhesion between the electrode / electrolyte integrated product and the current collector can be increased to reduce the contact resistance, thereby improving the battery performance. Because it can.

  The thickness of the substrate is preferably 0.3 mm or more and 5 mm or less. Within this range, the battery can be formed thinner while ensuring the strength of the substrate.

  It is preferable that the said current collection part is arrange | positioned over the edge part of a board | substrate. Thereby, the space of the edge part of a board | substrate can be utilized for the connection part of current collection parts.

  It is preferable that an insulating elastic body is further disposed around the electrode / electrolyte integrated body. As a result, the degree of adhesion between the substrates can be increased, and liquid fuel can be more reliably prevented from leaking out of the battery, and the adjacent electrode / electrolyte integrals can be insulated from each other. Further, since the substrates can be firmly bonded to each other, the degree of adhesion between the electrode / electrolyte integrated product and the current collector can be increased, the contact resistance can be reduced, and the battery performance can be improved.

  The insulating elastic body is preferably formed of at least one organic polymer material selected from the group consisting of silicone rubber, fluorine rubber, butyl rubber, urethane rubber, polypropylene, nylon, and polyethylene. This is because they are highly elastic and insulating and have high resistance to liquid fuel.

  The insulating elastic body preferably has a thickness of 0.1 mm to 5 mm. Within this range, the battery can be formed thinner while more reliably preventing liquid fuel from leaking out of the battery.

  It is preferable that the concave portion and the convex portion further include a fitting protrusion and a fitting groove, and the fitting protrusion and the fitting groove are fitted to each other. Thus, the substrates can be more reliably bonded to the repulsive force of the insulating elastic body and the expansion / contraction of the integrated electrode / electrolyte due to the battery reaction.

  A protrusion is further disposed on the surface of the concave portion of the substrate and around the current collecting portion, and a groove for inserting the protrusion is further disposed on the surface of the convex portion of the substrate and around the current collecting portion. It is preferable that Thereby, an electrode-electrolyte integrated object can be reliably arrange | positioned on a current collection part at the time of battery assembly.

  The liquid fuel storage part preferably further includes a gas-liquid separation hole sealed with a gas-liquid separation membrane. Thereby, the carbon dioxide produced | generated by discharge reaction can be discharged | emitted from a liquid fuel storage part, without making liquid fuel leak.

  Next, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is an exploded perspective view showing an example of the liquid fuel cell of the present invention. In FIG. 1, a plurality of electrode / electrolyte integrated bodies 1 are arranged between a pair of substrates 3a and 3b via a pair of insulating elastic bodies 2a and 2b. Moreover, the liquid fuel storage part 4 is arrange | positioned under the board | substrate 3b. The electrode / electrolyte integrated body 1 is formed by laminating and integrating a positive electrode, a negative electrode, and a solid electrolyte membrane, which will be described later.

  Current collectors 5a and 5b that are in electrical contact with the electrode / electrolyte integrated product 1 are disposed on part of the surfaces of the substrates 3a and 3b. The current collectors 5a and 5b are disposed over the ends of the substrates 3a and 3b, and at the ends, the positive current collector lead 6a, the negative current collector lead 6b, the positive external terminal 7a, and the negative external terminal 7b. Is forming. Each electrode / electrolyte integrated body 1 is electrically connected in series at once by a positive electrode current collecting lead portion 6a and a negative electrode current collecting lead portion 6b arranged above and below by joining the substrates 3a and 3b.

  The substrates 3a and 3b are made of an insulating resin such as epoxy resin with glass, polytetrafluoroethylene (PTFE), hard polyvinyl chloride, polypropylene, polyethylene, and the thickness is set to 0.3 mm to 5 mm. Yes. Moreover, the use of the insulating elastic bodies 2a and 2b can be omitted by using an insulating resin having a certain degree of elasticity for the substrates 3a and 3b.

  The liquid fuel storage unit 4 can be formed from, for example, a resin such as PTFE, hard polyvinyl chloride, polypropylene, or polyethylene, or a corrosion-resistant metal such as stainless steel.

  The current collectors 5a and 5b are formed from a metal thin film having a thickness of 1 μm to 200 μm, such as copper plating, gold plating, silver plating, or solder plating. The current collectors 5a and 5b are preferably formed by performing electroless copper plating on the surfaces of the substrates 3a and 3b and further performing gold plating thereon. This is because electroless copper plating is stable as conductive base plating on the substrates 3a and 3b made of an insulating resin, and gold plating is excellent in electrical characteristics such as contact resistance and corrosion resistance. Silver plating may be provided as an intermediate layer between the underlying copper plating and the gold plating thereon. By using silver plating that is cheaper and has higher electrical conductivity than gold plating as the intermediate layer, the current collecting portions 5a and 5b having a predetermined thickness can be formed at low cost.

  In addition, it is preferable that the current collectors 5a and 5b are arranged on the surface of the substrates 3a and 3b at approximately the same size and at equal intervals. Thereby, the current density which flows through the current collection parts 5a and 5b can be averaged.

  The substrate 3 a is provided with a convex portion 8, the substrate 3 b is provided with a concave portion 9, and the convex portion 8 and the concave portion 9 are formed so as to be fitted to each other. The substrate 3a is provided with an air hole 10 for supplying air to the electrode / electrolyte integrated product 1, and the substrate 3b is provided with a fuel supply hole 11 for supplying liquid fuel to the electrode / electrolyte integrated product 1. Yes. Further, the substrates 3a and 3b are provided with a gas-liquid separation hole 12 communicating with the liquid fuel storage unit 4, and a gas-liquid separation film 13 is disposed in the gas-liquid separation hole 12 of the substrate 3a.

  The insulating elastic bodies 2a and 2b are provided with openings 2a1, 2a2, 2b1, 2b2 at portions corresponding to the electrode / electrolyte integrated body 1 and the gas-liquid separation hole 12. The insulating elastic bodies 2a and 2b are made of an organic polymer material such as silicone rubber, fluororubber, butyl rubber, urethane rubber, polypropylene, nylon, and polyethylene, and the thickness is set to 0.1 mm to 5 mm. ing.

  FIG. 2 is a perspective view of a state in which a part of the liquid fuel cell of FIG. 1 is assembled. When the liquid fuel cell of the present embodiment shown in FIG. 1 is assembled, first, as shown in FIG. 2, the insulating elastic bodies 2a and 2b, the electrode / electrolyte integrated body 1 and the insulating elastic bodies 2a and 2b are placed in the recess 9 of the substrate 3b. Insert. In this state, the current collecting part 5b of the substrate 3b is accurately aligned and disposed on the lower surface of the electrode / electrolyte integrated body 1. Thereafter, by inserting the convex portion 8 of the substrate 3a into the concave portion 9 of the substrate 3b, the electrode / electrolyte integrated product 1 can be accurately disposed between the current collecting portion 5b of the substrate 3b and the current collecting portion 5a of the substrate 3a. At the same time, the positive electrode current collecting lead portion 6a and the negative electrode current collecting lead portion 6b arranged above and below can be electrically connected. Furthermore, when the substrate 3b and the liquid fuel storage unit 4 are joined by heat welding or the like, the liquid fuel cell of this embodiment is completed. In addition, the board | substrates 3a and 3b and the liquid fuel storage part 4 can also be joined by bolt fastening etc.

  FIG. 3 is a perspective view of the liquid fuel cell of FIG. 1 in a fully assembled state. In FIG. 3, the concave portion 9 of the substrate 3 b and the convex portion 8 of the substrate 3 a are fitted to each other, and the substrate 3 a and the substrate 3 b are joined via the electrode / electrolyte integrated product 1.

  4 is a cross-sectional view taken along the line II of FIG. 3, and FIG. 5 is a cross-sectional view taken along the line II-II of FIG. However, FIG. 4 and FIG. 5 show the dimension in the thickness direction enlarged as compared with FIG. 3 for easy understanding of the drawing.

  4 and 5, the electrode / electrolyte integrated product 1 is formed by laminating and integrating a positive electrode 14, a negative electrode 15, and a solid electrolyte film 16. Further, a plurality of electrode / electrolyte integrated products 1 are arranged on the same plane.

  The positive electrode 14 is formed by, for example, laminating a diffusion layer 14a made of a porous carbon material such as carbon cloth or carbon paper and a catalyst layer 14b made of carbon powder carrying a catalyst. The positive electrode 14 has a function of reducing oxygen, and for example, platinum fine particles, alloy fine particles of iron, nickel, cobalt, tin, ruthenium, gold or the like and platinum are used as the catalyst. The catalyst layer 14b may contain PTFE resin particles or proton exchange resin particles. Examples of proton exchange resins that can be used include polyperfluorosulfonic acid resins, sulfonated polyether sulfonic acid resins, and sulfonated polyimide resins. A carbon powder paste containing PTFE resin particles may be applied to the surface of the diffusion layer 14a on the catalyst layer 14b side in order to improve water repellency.

  The negative electrode 15 includes a diffusion layer 15a and a catalyst layer 15b, and has a function of generating protons from fuel, that is, a function of oxidizing fuel. For example, the negative electrode 15 can be configured similarly to the positive electrode.

  The solid electrolyte membrane 16 is made of a material that does not have electron conductivity but has only proton conductivity. For example, polyperfluorosulfonic acid resin membrane, specifically, “Nafion membrane” (trade name) manufactured by DuPont, “Flemion membrane” (trade name) manufactured by Asahi Glass Co., Ltd., “Aciplex membrane” manufactured by Asahi Kasei Kogyo Co., Ltd. A film such as “(trade name)” can be used. In other cases, a sulfonated polyether sulfonic acid resin film, a sulfonated polyimide resin film, a sulfuric acid-doped polybenzimidazole film, or the like can be used.

  The liquid fuel storage unit 4 that functions as a fuel tank is filled with a liquid fuel 17 that is a negative electrode active material. As the liquid fuel 17, for example, methanol aqueous solution, ethanol aqueous solution, dimethyl ether, sodium borohydride aqueous solution, potassium borohydride aqueous solution, lithium borohydride aqueous solution and the like are used.

  The liquid fuel 17 in the liquid fuel storage unit 4 is supplied to the negative electrode 15 through the fuel supply hole 11 provided in the substrate 3b. Further, a fuel suction material 18 impregnated and held with the liquid fuel 17 and supplied to the negative electrode 15 is disposed inside the liquid fuel storage unit 4 including a portion in contact with the negative electrode 15. Thereby, even if the liquid fuel 17 is consumed, the contact between the liquid fuel 17 and the negative electrode 15 is maintained, so that the liquid fuel 17 can be used up to the end. Glass fiber can be used as the fuel wicking material 18, but other materials can be used as long as they can be impregnated with liquid fuel and the dimensions do not change much by the impregnation and are chemically stable. Good.

  The substrate 3 a is provided with air holes 10, and oxygen in the air as the positive electrode active material is supplied to the positive electrode 14 through the air holes 10.

  Insulating elastic bodies 2 a and 2 b are disposed between the electrode / electrolyte integrated body 1. As a result, the degree of adhesion between the substrates 3a and 3b is increased, and the liquid fuel 17 can be more reliably prevented from leaking out of the battery, and the adjacent electrode / electrolyte integrated body 1 can be insulated from each other. In addition, since the substrates 3a and 3b can be firmly bonded to each other, the degree of adhesion between the electrode / electrolyte integrated body 1 and the current collectors 5a and 5b can be increased, the contact resistance can be reduced, and the battery performance can be improved.

  The diffusion layer 14a of the positive electrode 14 and the current collector 5a of the substrate 3a are electrically connected. Further, the diffusion layer 15a of the negative electrode 15 and the current collector 5b of the substrate 3b are electrically connected. As described above, the current collecting part 5a and the current collecting part 5b of the adjacent electrode / electrolyte integrated product 1 have the positive electrode current collecting lead part 6a and the negative electrode current collecting lead part 6b partially overlapped as described above. Therefore, it is electrically connected. Note that the positive electrode current collector lead portion 6a and the negative electrode current collector lead portion 6b are not shown in FIGS.

  The substrates 3a and 3b are provided with gas-liquid separation holes 12 communicating with the liquid fuel storage unit 4, and the gas-liquid separation holes 12 are sealed with a detachable gas-liquid separation film 13. The gas-liquid separation membrane 13 can be formed from a PTFE sheet having pores, and carbon dioxide generated by the discharge reaction can be released from the liquid fuel storage unit 4 without causing the liquid fuel 17 to leak. In addition, by making the gas-liquid separation membrane 13 removable, the gas-liquid separation hole 12 can be used as a filling port when the liquid fuel 17 is replenished.

(Embodiment 2)
FIG. 6 is a cross-sectional view (a diagram corresponding to FIG. 5 of Embodiment 1) showing another example of the liquid fuel cell of the present invention. In FIG. 6, the same reference numerals are given to portions common to FIG. 5.

  In the liquid fuel cell of the present embodiment, the fitting groove 19a is further provided on the side surface of the convex portion 8 of the substrate 3a, the fitting projection 19b is further provided on the side surface of the concave portion 9 of the substrate 3b, and the fitting groove 19a and the fitting projection are provided. The structure is the same as that of the liquid fuel cell of Embodiment 1 except that 19b is fitted. When the fitting groove 19a and the fitting projection 19b are fitted, the substrate 3a is more reliably protected against the repulsive force of the insulating elastic bodies 2a and 2b and the expansion / contraction of the electrode / electrolyte integrated body 1 due to the battery reaction. 3b can be joined.

(Embodiment 3)
FIG. 7 is a perspective view of a state in which a part of a liquid fuel cell showing still another example of the present invention is assembled (a diagram corresponding to FIG. 2 of Embodiment 1). In FIG. 7, parts common to FIG.

  The liquid fuel cell of this embodiment is the same as that of Embodiment 1 except that the electrode / electrolyte integrated body 1, the insulating elastic bodies 2a and 2b, and the substrates 3a and 3b are arranged on the upper and lower sides so as to sandwich the liquid fuel storage section 4. The structure is the same as that of a liquid fuel cell. By adopting the structure of this embodiment, the effective power generation area can be doubled, and the output of the liquid fuel cell can be increased.

(Embodiment 4)
FIG. 8 is a perspective view of a state in which a part of a liquid fuel cell showing still another example of the present invention is assembled (a diagram corresponding to FIG. 2 of Embodiment 1). In FIG. 8, the same reference numerals are given to parts common to FIG.

  The liquid fuel cell of this embodiment is the same as that of Embodiment 1 except that the electrode / electrolyte integrated body 1, the insulating elastic bodies 2a and 2b, and the substrates 3a and 3b are arranged vertically and horizontally so as to sandwich the liquid fuel storage unit 4. This is the same structure as the liquid fuel cell. With the structure of this embodiment, the effective power generation area can be quadrupled, and the output of the liquid fuel cell can be further increased.

(Embodiment 5)
FIG. 9 is an exploded perspective view (a diagram corresponding to FIG. 1 of Embodiment 1) showing still another example of the liquid fuel cell of the present invention. In FIG. 9, the same reference numerals are assigned to parts common to FIG.

  In the liquid fuel cell of the present embodiment, protrusions 20 and 21 are provided around the current collecting part 5b of the substrate 3b, and a groove 22 into which the protrusions 20 and 21 are inserted around the current collecting part 5a of the substrate 3a. , 23, except that the liquid fuel cell of Embodiment 1 is provided. By adopting the structure of the present embodiment, the plurality of electrode / electrolyte integrated bodies 1 can be accurately aligned with the positions in contact with the current collectors 5a and 5b.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to said embodiment.

  As described above, the present invention can reduce the number of assembling steps of the liquid fuel cell and simplify the assembling work, and can provide a small and thin liquid fuel cell with high productivity. Further, by using the liquid fuel cell of the present invention as a power source for a cordless device such as a personal computer or a mobile phone, a long continuous use time of the cordless device can be secured.

It is a disassembled perspective view which shows an example of the liquid fuel cell of this invention. FIG. 2 is a perspective view of a state in which a part of the liquid fuel cell of FIG. 1 is assembled. FIG. 2 is a perspective view of the liquid fuel cell of FIG. 1 in a fully assembled state. It is sectional drawing of the II line | wire of FIG. It is sectional drawing of the II-II line | wire of FIG. It is sectional drawing which shows another example of the liquid fuel cell of this invention. It is a perspective view in the state where a part of liquid fuel cell which shows other examples of the present invention was assembled. It is a perspective view in the state where a part of liquid fuel cell which shows other examples of the present invention was assembled. It is a disassembled perspective view which shows another example of the liquid fuel cell of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrode / electrolyte integrated body 2a, 2b Insulating elastic body 2a1, 2a2, 2b1, 2b2 Opening part 3a, 3b Substrate 4 Liquid fuel storage part 5a, 5b Current collecting part 6a Positive electrode current collecting lead part 6b Negative electrode current collecting lead part 7a Positive electrode external terminal part 7b Negative electrode external terminal part 8 Convex part 9 Concave part 10 Air hole 11 Fuel supply hole 12 Gas-liquid separation hole 13 Gas-liquid separation film 14 Positive electrode 14a Diffusion layer 14b Catalyst layer 15 Negative electrode 15a Diffusion layer 15b Catalyst layer 16 Solid electrolyte Membrane 17 Liquid fuel 18 Fuel suction material 19a Fitting groove 19b Fitting protrusions 20, 21 Protrusions 22, 23 Grooves

Claims (13)

A liquid fuel cell comprising a positive electrode that reduces oxygen, a negative electrode that oxidizes fuel, a solid electrolyte disposed between the positive electrode and the negative electrode, and a liquid fuel storage unit,
The positive electrode, the negative electrode, and the solid electrolyte constitute an electrode / electrolyte integrated product,
A plurality of the electrode / electrolyte integrated products are arranged between a pair of substrates,
A part of the surface of the substrate is provided with a current collector that is in electrical contact with the electrode / electrolyte integrated product,
The plurality of electrode / electrolyte integrated products are electrically connected by the current collector,
One of the substrates comprises a recess,
The other of the substrates has a convex portion,
The pair of substrates are fitted to each other by the concave portion and the convex portion.   The liquid fuel cell according to claim 1, wherein the current collector is formed of a metal thin film.   The liquid fuel cell according to claim 2, wherein the metal thin film is formed of at least one kind of plating selected from the group consisting of copper plating, gold plating, silver plating, and solder plating.   The liquid fuel cell according to claim 3, wherein the plating has a thickness of 1 μm to 200 μm.   2. The liquid fuel cell according to claim 1, wherein the substrate is made of at least one resin selected from the group consisting of glass-filled epoxy resin, polytetrafluoroethylene, hard polyvinyl chloride, polypropylene, and polyethylene.   The liquid fuel cell according to claim 5, wherein the thickness of the substrate is not less than 0.3 mm and not more than 5 mm.   The liquid fuel cell according to claim 1, wherein the current collector is disposed over an end of the substrate.   The liquid fuel cell according to claim 1, wherein an insulating elastic body is further disposed around the electrode / electrolyte integrated body.   The liquid according to claim 8, wherein the insulating elastic body is formed of at least one organic polymer material selected from the group consisting of silicone rubber, fluorine rubber, butyl rubber, urethane rubber, polypropylene, nylon, and polyethylene. Fuel cell.   The liquid fuel cell according to claim 9, wherein the insulating elastic body has a thickness of 0.1 mm to 5 mm.   The liquid fuel cell according to claim 1, wherein the concave portion and the convex portion further include a fitting protrusion and a fitting groove, and the fitting protrusion and the fitting groove are fitted to each other.   A protrusion is further disposed on the surface of the concave portion of the substrate and around the current collecting portion, and the protrusion is inserted on the surface of the convex portion of the substrate and around the current collecting portion. The liquid fuel cell according to claim 1, further comprising a groove.   The liquid fuel cell according to claim 1, wherein the liquid fuel storage unit further includes a gas-liquid separation hole sealed with a gas-liquid separation membrane.

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