JP2010160934A - Fuel cell system and electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell system which can discharge a generated gas resulting from a reaction at an anode to the outside without allowing the generated gas to be mixed with air in a cathode to achieve a higher output power and an improved output stability, and to provide an electronic apparatus having the fuel cell system. <P>SOLUTION: The fuel cell system includes a fuel cell stack and a gas concentration unit, and the anodes of unit cells in the fuel cell stack communicate with the gas concentration unit through a generated gas discharging channel formed on the fuel cell stack. The fuel cell stack includes one or more fuel cell layers each having two or more unit cells arranged on the same plane, each unit cell, preferably, being composed of a cathode, an electrolytic film, an anode, and an anode current-collecting layer that are stacked in this order. The gas concentration unit has an internal cavity and an opening communicating with the cavity. It is preferable that the cavity communicate with the anodes of all of the unit cells of at least one fuel cell layer through the generated gas discharging channel. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fuel cell system capable of improving output and stability, and an electronic device equipped with the fuel cell system.

  In recent years, as a small power source for portable electronic devices that support the information-oriented society, there is a possibility that high power generation efficiency can be obtained as a single power generation device. A fuel cell utilizes an electrochemical reaction that oxidizes fuel (for example, hydrogen, methanol, ethanol, hydrazine, formalin, formic acid, etc.) at the anode electrode and reduces oxygen in the air at the cathode electrode. It is a chemical battery that supplies electrons.

  Among various types of fuel cells, a polymer electrolyte fuel cell (hereinafter referred to as “PEMFC”) using a proton-exchanged ion exchange membrane as an electrolyte membrane is high even at a low temperature operation of 100 ° C. or less. Because power generation efficiency is obtained, it is not necessary to apply heat from the outside compared to fuel cells that operate at high temperatures such as phosphoric acid fuel cells and solid oxide fuel cells, and large-scale auxiliary equipment is not required. It has the potential for practical use as a compact power supply.

  As the fuel supplied to such a PEMFC, hydrogen gas using a high-pressure gas cylinder, a mixed gas of hydrogen gas and carbon dioxide gas obtained by decomposing an organic liquid fuel with a reformer, or the like is used.

  A direct methanol fuel cell (hereinafter referred to as “DMFC”) that generates power by supplying a methanol aqueous solution to the anode electrode of a PEMFC and taking out protons and electrons directly from the methanol aqueous solution is a reformer. Therefore, it has the potential to be put into practical use as a compact power supply more than PEMFC. Furthermore, since methanol aqueous solution that is liquid at atmospheric pressure is used as fuel, fuel with high volumetric energy density can be handled in a simple container without using a high-pressure gas cylinder, and it is safe as a compact power source. In addition, the fuel container can be made small. Therefore, DMFC has attracted attention from the viewpoint of application to a small power source of a portable electronic device, in particular, a secondary battery replacement application for a portable electronic device.

In DMFC, the following reactions occur at the anode and cathode, respectively.
Anode electrode: CH ₃ OH + H ₂ O → CO ₂ + 6H ⁺ + 6e ⁻
Cathode: O ₂ + 4H ⁺ + 4e ⁻ → 2H ₂ O
Thus, in the DMFC, carbon dioxide is generated as a gas on the anode side, and water is generated on the cathode side.

  Conventionally, in DMFC, carbon dioxide gas generated by the reaction is discharged on a flow of methanol aqueous solution on the anode electrode side as fuel, and a mixture of the discharged carbon dioxide gas and aqueous methanol solution is separated. Separately, a gas-liquid separator or the like has been provided, and the separated methanol aqueous solution has been used again as fuel. However, in this case, there is a problem that the fuel cell system is increased in size and weight.

  In response to this problem, Patent Document 1 discloses a DMFC that includes a gas-permeable layer provided in a fuel electrode chamber of a membrane electrode assembly and can passively discharge carbon dioxide outside the system. By providing a gas permeable layer, a gas-liquid separation device is not required, and carbon dioxide generated by the reaction can be removed from the anode compartment, so that accumulation of carbon dioxide that can interfere with the reaction at the anode is prevented. Can be avoided.

JP 2005-518646 A

  However, in the membrane electrode assembly described in Patent Document 1, the carbon dioxide removed through the gas permeable layer is removed from the anode compartment, but how is the carbon dioxide removed outside the fuel cell system? There is no description about whether to discharge. When carbon dioxide accumulates in the fuel cell system, passive air can be used without using auxiliary equipment as much as possible to reduce power consumption, especially as a method of supplying air used for the reaction at the cathode (air electrode). In the passive type fuel cell that performs supply, the problem is that the output decreases when carbon dioxide removed from the fuel electrode compartment is mixed with the air of the cathode electrode (air electrode).

  The present invention has been made to solve the above-mentioned problems, and its purpose is to mix a produced gas such as carbon dioxide generated by a reaction at an anode electrode (fuel electrode) with air at a cathode electrode (air electrode). The fuel cell system can be discharged to the outside of the fuel cell system, and thus a high output and improved output stability are realized, and an electronic device (fuel cell mounted electronic device) including the fuel cell system is provided. Is to provide.

  The present invention includes a fuel cell stack and a gas concentration part, and an anode electrode of the unit cell included in the fuel cell stack and a gas concentration part communicate with each other through a product gas discharge channel provided in the fuel cell stack. A battery system is provided. In the present invention, the fuel cell stack includes at least one unit cell. In the fuel cell stack of the present invention, the fuel cell stack is preferably a fuel cell in which two or more unit cells each having a cathode electrode, an electrolyte membrane, an anode electrode, and an anode current collecting layer in this order are arranged on the same plane. The gas concentration part includes one or more layers, and the gas concentration part is preferably a hollow body having a hollow part therein, and includes an opening communicating with the hollow part. The gas concentrator is for concentrating the generated gas generated by the power generation of the unit cell, and the opening is for discharging the generated gas collected in the gas concentrator to the outside of the fuel cell system. is there. Here, in the fuel cell system of the present invention, the cavity portion included in the gas collecting portion and the anode electrodes of all unit cells included in at least one fuel cell layer among the fuel cell layers are provided in the fuel cell stack. It is preferable to communicate with the product gas discharge channel.

  In the present invention, the fuel cell stack includes a fuel cell layer in which two or more unit cells are arranged on the same plane and a spacer layer composed of one or more spacers, and the anode current collecting layer of the unit cell is the spacer. Including one or more fuel cells laminated so as to be in contact with each other, and a cavity portion included in the gas concentration portion and anode electrodes of all unit cells included in at least one fuel cell layer are provided inside the fuel cell. It is preferable to communicate with the product gas discharge channel.

  In one preferred embodiment of the present invention, the gas concentrating portion is connected to the end portions of all the spacers included in at least one spacer layer, and the product gas discharge flow path includes the anode current collecting layer of the unit cell. A through-hole penetrating in the thickness direction and a flow path formed in the spacer that communicates with the through-hole and extends to an end connected to the gas collecting portion.

  In another preferred embodiment of the present invention, the gas concentrating portion is connected to end portions of all unit cells included in at least one fuel cell layer, and the product gas discharge channel is an anode of the unit cell. It is formed in the anode current collecting layer so as to be in contact with the electrode, and is composed of a flow path extending to an end connected to the gas collecting portion. In this way, when the product gas discharge channel is provided in the unit cell, the fuel cell stack does not necessarily have a spacer layer. When the fuel cell stack does not have a spacer layer, the fuel cell stack is composed of one fuel cell layer in which two or more unit cells are arranged on the same plane, or two or more such fuel cell layers are stacked. It is constituted by doing.

  In the fuel cell system of the present invention, the fuel cell stack is formed by stacking two or more of the above fuel cells, and the gas concentration part is the end of all the spacers included in the fuel cell stack or all the fuel cell stacks include. A flow path for discharging generated gas, which is connected to the end of the unit cell, and in which the hollow part of the gas collecting part and the anode poles of all the unit cells of the fuel cell stack are provided inside each fuel cell It is preferable that they communicate with each other. The fuel cell layer constituting the fuel cell stack is preferably formed by arranging two or more unit cells with a gap on the same plane.

  The fuel cell system of the present invention may include one or more gas collecting portions, but all of the gas collecting portions are preferably disposed adjacent to one side surface of the fuel cell stack.

  The gas collecting part preferably includes a hollow product gas guide path connected to the opening. Such a product gas guiding path is suitable for adjusting the discharge position in the fuel cell system of the product gas collected in the gas collecting unit.

  The gas concentrating section has a harmful component removal filter (for removing harmful components in the exhausted generated gas) at an opening (gas exhaust port) opposite to the opening side of the gas concentrating section in the generated gas guiding path. A filter) may be provided. Further, the inner wall surface of the generated gas guiding path may be subjected to water repellent treatment.

  In the fuel cell stack provided in the fuel cell system of the present invention, the spacer layer may be formed by arranging two or more spacers with a gap on the same plane. In this case, in the fuel cell included in the fuel cell stack, it is preferable that two or more unit cells included in the fuel cell layer and two or more spacers included in the spacer layer are arranged so as to intersect with each other.

  Moreover, this invention provides an electronic device (electronic device mounted with a fuel cell) provided with said fuel cell system. In the case where the gas concentration part of the fuel cell system includes the generated gas guiding path, the generated gas guiding path may be composed of any component member that constitutes an electronic device in which a hollow portion is formed.

  In the electronic device including the fuel cell system of the present invention, it is preferable that the opening (gas discharge port) on the opposite side to the opening side of the gas collecting portion in the generated gas guiding path is disposed at the outer edge of the electronic device. Moreover, it is preferable that the said opening (gas discharge port) is arrange | positioned at the back side (the side opposite to the side which the user opposes at the time of use of the said electronic device) of the electronic device.

  In the electronic device of the present invention, the fuel cell system is disposed in a position where air can be supplied from the outside of the electronic device to at least a part of the outer surface of the fuel cell stack included in the fuel cell system. The gas concentration part of the system is preferably arranged adjacent to an outer surface different from the outer surface of the fuel cell stack to which air is supplied from the outside of the electronic device. The electronic device of the present invention may include, for example, a battery housing chamber that houses the fuel cell system or the fuel cell stack. In such a case, by mounting the fuel cell system or the fuel cell stack in the battery housing chamber, the electronic device (fuel cell mounted electronic device) of the present invention is constructed. The battery housing chamber preferably has an opening that communicates the inside with the outside of the electronic device. Such an opening serves as an air intake port for supplying air to the fuel cell stack housed in the battery housing chamber.

  According to the present invention, the produced gas such as carbon dioxide generated by the reaction at the anode electrode (fuel electrode) can be discharged outside the fuel cell system without being mixed with the air at the cathode electrode (air electrode). This can effectively prevent the oxygen partial pressure of the cathode electrode (air electrode) from being reduced by mixing the product gas. Therefore, according to the present invention, it is possible to provide a fuel cell system with high output density and improved output stability.

  Such a fuel cell system of the present invention can be suitably applied as a power source for electronic devices, particularly portable electronic devices.

It is a perspective view which shows typically a preferable example of the fuel cell system of this invention. It is a perspective view which shows typically the fuel cell stack which comprises the fuel cell system shown by FIG. FIG. 3 is a cross-sectional view taken along line III-III of the fuel cell stack shown in FIG. 2. It is sectional drawing which shows another preferable example of the fuel cell stack which comprises the fuel cell system of this invention. FIG. 5 is a diagram schematically showing a part of an anode current collecting layer used in the fuel cell stack shown in FIG. 4. It is a perspective view which shows typically a preferable example of an electronic device provided with the fuel cell system of this invention. It is a figure which shows typically another preferable example of an electronic device provided with the fuel cell system of this invention. FIG. 8 is a diagram schematically illustrating a fuel cell system (including a generated gas guiding path) included in the electronic device illustrated in FIG. 7. 3 is a cross-sectional view showing an anode current collecting layer produced in Example 1. FIG. 3 is a cross-sectional view showing a spacer manufactured in Example 1. FIG. 1 is a top view schematically showing a unit of a fuel cell manufactured in Example 1. FIG.

  Hereinafter, the fuel cell system and electronic device of the present invention will be described in more detail with reference to embodiments.

<< First Embodiment >>
FIG. 1 is a perspective view schematically showing a preferred example of the fuel cell system of the present invention. A fuel cell system 100 shown in FIG. 1 includes a fuel cell stack 101 including a plurality of unit cells 103, and a generated gas (for example, mainly carbon dioxide when an aqueous methanol solution is used as a fuel) generated by power generation of the unit cells. It is a complex with the gas concentrating unit 102 for consolidating. In the fuel cell system 100 including such a gas concentrating unit 102, generated gas such as carbon dioxide generated at the anode electrode of each unit cell 103 of the fuel cell stack 101 is discharged from the generated gas formed in the fuel cell stack 101. The gas is aggregated in the gas aggregating section 102 through a use channel (not shown in FIG. 1). The aggregated generated gas is discharged to the outside of the fuel cell system 100 from the end opening (gas exhaust port 106) of the generated gas guiding path 105 connected to the opening 104 of the gas aggregating section 102. On the other hand, the air supplied to the cathode electrode of each unit cell 103 is one or more outer surfaces of the outer surface (upper and lower surfaces and side surfaces) of the fuel cell stack 101 where the gas concentrating unit 102 is not installed adjacently. Is taken into the fuel cell stack 101.

  As is clear from the Nernst equation, when the oxygen partial pressure on the cathode electrode (air electrode) side decreases, the standard electromotive force of the unit cell decreases and the output of the fuel cell decreases. According to the configuration of the fuel cell system 100 of the present embodiment, the generated gas such as carbon dioxide generated at the anode electrode of each unit cell 103 is not mixed with the air at the cathode electrode, and is outside the fuel cell system 100. Since it can discharge | emit, it becomes possible to prevent the output fall by the fall of the oxygen partial pressure in a cathode electrode. In addition, it is possible to prevent a decrease in output due to an internal current that occurs when methanol water vapor contained in the separated product gas flows into the cathode. Hereinafter, the fuel cell stack 101 and the gas collecting unit 102 that constitute the fuel cell system 100 of the present embodiment will be described in detail.

<Fuel cell stack>
(1) Structure of Fuel Cell Stack FIG. 2 is a perspective view schematically showing a fuel cell stack 101 constituting the fuel cell system 100 shown in FIG. Referring to FIG. 2, in fuel cell stack 101, three strip-shaped unit cells 103 having a long side and a short side are arranged on the same plane so that a gap 130 is formed between unit cells 103. The first fuel cell layer 110 and the four strip-shaped spacers 107 having a long side and a short side are arranged on the same plane so that a gap 140 is formed between the spacers 107. A first spacer layer 115, a second fuel cell layer 120 having the same structure as the first fuel cell layer 110, a second spacer layer 125 having the same structure as the first spacer layer 115, Are laminated in this order. By interposing the first spacer layer 115 between the first fuel cell layer 110 and the second fuel cell layer 120, the two fuel cell layers are arranged apart from each other. A space (the space includes a gap 140 formed between the spacers) is formed between the fuel cell layers.

  The unit cell 103 used in the fuel cell stack 101 has a strip shape having a long side and a short side, more specifically, a rectangular parallelepiped shape. In the first fuel cell layer 110 and the second fuel cell layer 120, the three unit cells 103 have a gap 130 between adjacent unit cells so that their long sides are opposed to each other in the same plane. As formed, they are spaced apart in parallel or substantially parallel. Similarly, the spacer 107 used in the fuel cell stack 101 has a strip shape having a long side and a short side, more specifically, a rectangular parallelepiped shape. In the first spacer layer 115 and the second spacer layer 125, the four spacers 107 are arranged in the same plane so that their long sides are opposed to each other, and a gap 140 is formed between adjacent spacers. Are spaced apart in parallel or substantially in parallel.

  The first fuel cell layer 110 and the first spacer layer 115 adjacent thereto intersect with each other so that the unit cell 103 included in the first fuel cell layer 110 and the spacer 107 included in the first spacer layer 115 intersect each other. Preferably, they are laminated so as to be orthogonal or substantially orthogonal. Thereby, the area which the spacer 107 and the unit battery 103 contact can be made small, and the area which the unit battery 103 is directly exposed to the said space part can be enlarged. For this reason, the supply resistance of oxygen in the air to the cathode electrode of the unit cell 103 can be further reduced, and the output characteristics can be maintained well. The same applies to the first spacer layer 115 and the second fuel cell layer 120 adjacent thereto, and the second fuel cell layer 120 and the second spacer layer 125 adjacent thereto. Further, in the fuel cell stack 101 of the present embodiment, the first fuel cell layer 110 and the second fuel cell layer 120 are the second fuel cells directly below the unit cell 103 included in the first fuel cell layer 110. The unit cells 103 constituting the battery layer 120 are stacked so as to be arranged. The same applies to the first spacer layer 115 and the second spacer layer 125.

  Further, all the unit cells 103 constituting the first fuel cell layer 110 are arranged so that the anode electrode side thereof faces the first spacer layer 115 (not shown in FIG. 2). Similarly, all the unit cells 103 constituting the second fuel cell layer 120 are arranged so that the anode electrode side faces the second spacer layer 125. With this configuration, the anode current collecting layer of all the unit cells 103 comes into contact with the spacers constituting the adjacent spacer layer. In the present specification, a stack of such a fuel cell layer and a spacer layer disposed adjacent to the fuel cell layer is referred to as a “fuel cell” (spacer integrated fuel cell). A “fuel cell” can be suitably used as a unit constituting a fuel cell stack.

  Further, as will be described in detail later, the fuel cell stack 101 is configured such that the generated gas such as carbon dioxide generated at the anode electrode of the unit cell 103 is transferred to the gas collecting unit 102 through the discharge channel formed in the spacer 107. It is configured to be introduced. Preferably, each of the spacers 107 is arranged so that at least one end protrudes from an adjacent fuel cell layer so that the spacer 107 can be connected to the gas collecting portion.

The fuel cell stack 101 having the above structure has the following advantages, for example.
(A) The generated gas generated at the anode electrode of the unit cell 103 of the first fuel cell layer 110 can be suppressed or prevented from being discharged near the cathode electrode of the unit cell 103 of the second fuel cell layer 120. As a result, the high output characteristics of the unit cell can be maintained without obstructing the supply of oxygen to the cathode electrode of the unit cell 103 of the second fuel cell layer 120.
(B) The plurality of gaps 130 included in the first fuel cell layer 110 and the second fuel cell layer 120 and the gap 140 included in the first spacer layer 115 and the second spacer layer 125 are three-dimensionally connected to each other. Since it communicates and air diffusibility is good, air can be efficiently supplied to the cathode electrode of the unit cell 103 located inside the fuel cell stack 101. That is, the air that has entered the fuel cell stack 101 can be supplied by natural convection or diffusion through the communicating gap 130 and gap 140 to the inside of the fuel cell stack 101.
(C) The natural diffusibility of air in the fuel cell stack 101 is good. The air in the fuel cell stack 101 heated by the heat generated by the power generation is discharged to the outside of the fuel cell stack 101 through the communicating gap 130 and the gap 140 by convection, and the side surface of the fuel cell stack 101. Air is efficiently inhaled from the top and bottom surfaces. Therefore, an auxiliary machine such as an air pump or a fan for supplying air is not necessarily required, and this allows the fuel cell system 100 using the fuel cell stack 101 to be reduced in size. Further, even when an auxiliary machine such as an air pump or a fan is used, it is possible to reduce wind power necessary for supplying air to the inside of the fuel cell stack 101. This enables low power consumption and miniaturization of the auxiliary machine.

  The fuel cell stack 101 in the present embodiment may be variously modified without departing from the spirit of the present invention. For example, the number of fuel cell layers and spacer layers included in the fuel cell stack is not particularly limited as long as it has at least one fuel cell layer and one spacer layer (that is, one fuel cell). Further, the number of unit cells in the fuel cell layer and the number of spacers in the spacer layer are not particularly limited, and each may be 1 or more. The number of unit cells in the fuel cell layer is preferably 2 or more. In view of the efficiency of supplying air into the fuel cell stack and the like, the number of spacers is preferably 2 or more, and these spacers are preferably arranged in the same plane so that a gap is formed between the spacers.

  Further, the shape of each unit battery and the spacer is not limited to a rectangular parallelepiped shape, and for example, the cross-sectional shape may be circular or elliptical. However, in order to construct the fuel cell stack with good stability so that the gap of the fuel cell layer and the gap of the spacer layer communicate three-dimensionally, the unit cell and the spacer have a long side and a short side. It is preferable to have a strip shape having

  Further, the first fuel cell layer 110 and the second fuel cell layer 120 are formed by the unit cells 103 constituting the second fuel cell layer 120 immediately below the unit cells 103 included in the first fuel cell layer 110. It is not always necessary to be stacked so as to be disposed. For example, even if stacked so that the gap 130 of the second fuel cell layer is disposed immediately below the unit cell 103 included in the first fuel cell layer 110. Good. The same applies to the first spacer layer 115 and the second spacer layer 125.

(2) Structure of Unit Battery and Spacer Next, the structure of the unit battery 103 and the spacer 107 provided in the fuel cell stack 101 of this embodiment will be described. 3 is a cross-sectional view taken along line III-III of the fuel cell stack 101 shown in FIG. As shown in FIG. 3, the unit cell 103 constituting the first fuel cell layer 110 and the second fuel cell layer 120 includes a cathode electrode 204, an electrolyte membrane 202, an anode electrode 203, and an anode current collecting layer 205. Prepare in order. More specifically, the unit battery 103 includes an electrolyte membrane 202, an anode electrode 203 disposed on one surface of the electrolyte membrane 202, a cathode electrode 204 disposed on the other surface of the electrolyte membrane 202, and an anode electrode. The anode current collecting layer 205 is disposed in contact with the surface opposite to the surface facing the electrolyte membrane 202 of 203.

  As described above, the shape of the unit cell 103 included in the fuel cell stack 101 of the present embodiment is preferably a strip shape having a long side and a short side, and more preferably a rectangular parallelepiped shape. The air flowing into the fuel cell stack 101 from the gap 130 on the uppermost surface or the lowermost surface of the fuel cell stack 101 convects or diffuses in the space between the fuel cell layers toward the short side of the unit cell 103, thereby diffusing the unit cell. 103 is supplied to the cathode electrode 204. For this reason, from the viewpoint of shortening the moving distance in the air supply, the length of the short side of the unit battery 103 is preferably 10 mm or less, and more preferably 5 mm or less. Thereby, the supply resistance of air can be reduced, and even in passive air supply that does not use an auxiliary machine such as a fan or a blower, it is possible to suppress a decrease in output due to insufficient air supply.

  Between the first fuel cell layer 110 and the second fuel cell 120, the first spacer layer 115 composed of the spacer 107 as described above is interposed, and the first fuel cell layer 110 is The spacer 107 constituting the first spacer layer 115 and the anode current collecting layer 205 of the unit cell 103 constituting the first fuel cell layer 110 are laminated on the first spacer layer 115 so as to contact each other. . The first fuel cell layer 110 and the first spacer layer 115 form one “fuel cell” unit in the fuel cell stack 101. Similarly, the second fuel cell layer 120 and the second spacer layer 125 (not shown in FIG. 3) form one fuel cell unit. All unit cells 103 constituting the second fuel cell layer 120 are arranged such that the cathode electrode 204 faces the first spacer layer 115.

  Here, in the fuel cell stack 101 in the present embodiment, each “fuel cell” so that the generated gas generated at the anode electrode 203 of all the unit cells 103 included in the fuel cell stack 101 can be guided to a gas aggregation unit described later. For each unit, a “product gas discharge channel” is provided in the interior thereof to communicate the hollow part of the gas collecting part and the anode electrodes 203 of all the unit cells 103 of the fuel cell layer of each fuel cell. Yes. In the present embodiment, with reference to FIG. 3, the production gas discharge flow path includes all the fuel cell layers (each of the first fuel cell layer 110 and the second fuel cell layer 120) of each fuel cell. A through hole 206 penetrating the anode current collecting layer 205 of the unit cell 103 in the thickness direction, a discharge channel 207 formed in the spacer 107, communicating with the through hole 206, and having one end extending to the end of the spacer 107; It is composed of As will be described later, the end of the spacer 107 in which the discharge flow path 207 is formed is connected to the gas collecting portion, whereby the cavity portion of the gas collecting portion and the fuel cell layer of each fuel cell are connected. The anode electrodes 203 of all the unit cells 103 are communicated.

  In the present embodiment, the discharge flow path 207 formed in the spacer 107 is formed on the surface of the rectangular parallelepiped spacer 107 facing the anode current collecting layer 205 of the unit cell 103 arranged in contact with the spacer 107. The groove 107 extends in the longitudinal direction of the spacer 107 (extends in parallel or substantially parallel to the long side of the spacer). Of the opening of the groove, the portion not closed by the unit cell 103 (the portion in contact with the gap 130 formed between the unit cells 103) does not leak the generated gas generated at the anode electrode into the fuel cell stack. The gas permeation preventive layer 150 is sealed (see FIGS. 2 and 3).

  Hereinafter, the constituent members and spacers constituting the unit battery used in the present invention will be described in more detail.

(Electrolyte membrane)
The electrolyte membrane (electrolyte membrane 202 in FIG. 3) is not particularly limited as long as it is a material having proton conductivity and electrical insulation, but is preferably a conventionally known appropriate polymer membrane, inorganic membrane or composite. It consists of a membrane. Examples of the polymer membrane include perfluorosulfonic acid electrolyte membrane (Nafion (NAFION (registered trademark): manufactured by DuPont), Dow membrane (manufactured by Dow Chemical), Aciplex (ACIPLEX (registered trademark): manufactured by Asahi Kasei). ), Flemion (registered trademark: manufactured by Asahi Glass Co., Ltd.), and hydrocarbon electrolyte membranes such as polystyrene sulfonic acid and sulfonated polyether ether ketone, etc. Examples of inorganic membranes include phosphate glass and cesium hydrogen sulfate. And a film made of polytungstophosphoric acid, ammonium polyphosphate, etc. Further, examples of the composite film include Gore Select film (Gore Select (registered trademark): manufactured by Gore).

  When the fuel cell stack (or a unit cell included therein) reaches a temperature of about 100 ° C. or higher in the usage environment, the sulfonated polyimide, 2-acrylamide having high ionic conductivity even at low water content -2-Methylpropanesulfonic acid (AMPS), sulfonated polybenzimidazole, phosphonated polybenzimidazole, cesium hydrogen sulfate, ammonium polyphosphate, ionic liquid (room temperature molten salt), etc. were used to form a film. It is preferable to use one as the electrolyte membrane.

The electrolyte membrane preferably has a proton conductivity of 10 ⁻⁵ S / cm or more, and a polymer electrolyte membrane having a proton conductivity of 10 ⁻³ S / cm or more such as a perfluorosulfonic acid polymer or a hydrocarbon-based polymer. More preferably, it is used.

(Anode and cathode)
The anode electrode (anode electrode 203 in FIG. 3) includes a catalyst that promotes the oxidation of fuel, and the fuel causes an oxidation reaction on the catalyst to generate protons and electrons. Further, the cathode electrode (cathode electrode 204) includes a catalyst that promotes the reduction of the oxidant. On the catalyst, the oxidant takes in protons and electrons, and a reduction reaction occurs. The fuel supplied to the fuel cell system of the present invention includes alcohols such as methanol and ethanol; ethers such as dimethyl ether; carboxylic acids such as formic acid; esters such as methyl formate; acetals such as dimethoxymethane; These aqueous solutions can be mentioned. In addition, although these illustrated fuels are all liquid at normal temperature, these liquid fuels may be vaporized and supplied as gas. In the present invention, only one kind of fuel may be used, or two or more kinds thereof may be mixed and used. Of these, methanol or an aqueous solution thereof is preferably used from the viewpoint of energy density per volume and activation overvoltage.

  As the anode electrode and the cathode electrode, for example, a laminated structure of a catalyst layer containing a carrier carrying a catalyst and an electrolyte and a porous substrate laminated on the catalyst layer can be used. In this case, the anode catalyst in the anode catalyst layer has a function of promoting the reaction rate of generating protons and electrons from, for example, methanol and water, and the electrolyte has a function of conducting the generated protons to the electrolyte membrane. The anode carrier has a function of conducting the generated electrons to the anode porous substrate. The anode porous substrate can supply methanol and water to the anode catalyst layer by the voids included therein, and has a function of conducting electrons from the anode support to the anode current collecting layer.

  On the other hand, the cathode catalyst in the cathode catalyst layer has a function of accelerating the reaction rate for generating water from oxygen, protons and electrons, and the electrolyte has a function of conducting protons from the electrolyte membrane to the vicinity of the cathode catalyst. The cathode carrier has a function of conducting electrons from the cathode porous substrate to the cathode catalyst. Also, the cathode porous substrate can supply oxygen to the cathode catalyst layer by the voids that it has, and has a function of conducting electrons from an external wiring (not shown) or spacer to the cathode catalyst layer. Have

  The anode carrier and the cathode carrier have a function of electron conduction, but the catalyst does not necessarily have to be provided because the catalyst also has electron conductivity. In addition, the anode porous substrate and the cathode porous substrate are not necessarily provided. In this case, the anode catalyst layer and the cathode catalyst layer are directly formed on the electrolyte membrane, and the anode catalyst layer includes the anode current collecting layer, the cathode catalyst layer, and the cathode catalyst layer. The layer exchanges electrons with external wiring (not shown) or spacers.

  Examples of the anode catalyst and the cathode catalyst include noble metals such as Pt, Ru, Au, Ag, Rh, Pd, Os, Ir; Ni, V, Ti, Co, Mo, Fe, Cu, Zn, Sn, W, Zr Examples include base metals such as these; oxides, carbides and carbonitrides of these noble metals or base metals; and carbon. One or a combination of two or more of these materials can be used as a catalyst. The anode catalyst and the cathode catalyst are not necessarily limited to the same type, and different materials can be used.

  The support used for the anode catalyst layer and the cathode catalyst layer is preferably a carbon-based material having high electrical conductivity, such as acetylene black, ketjen black (registered trademark), amorphous carbon, carbon nanotube, carbon nanohorn, etc. Is exemplified. In addition to these carbon-based materials, noble metals such as Pt, Ru, Au, Ag, Rh, Pd, Os, Ir; Ni, V, Ti, Co, Mo, Fe, Cu, Zn, Sn, W, Zr As well as these noble metals or base metal oxides, carbides, nitrides, carbonitrides, and the like can be used. These materials can be used alone or in combination of two or more as the carrier. Further, a material imparted with proton conductivity, specifically, sulfated zirconia, zirconium phosphate, or the like may be used as the carrier.

  The support used for the anode catalyst layer in the present invention preferably has a hydrophilic surface. As a method of hydrophilizing the surface, a method of modifying the surface with a hydrophilic functional group such as a carboxyl group or a hydroxyl group can be preferably used. Specific examples include surface modification by graft polymerization on the carbon surface and surface modification with a silane coupling agent. As a result, the anode catalyst layer holds the aqueous methanol solution in the pores, so that the diffusion of fuel and protons is improved and the amount of oxygen that can enter from the product gas discharge flow path reaches the anode catalyst. Therefore, it is possible to prevent a decrease in output characteristics caused by the reaction of oxygen in the anode catalyst layer.

  The electrolyte used for the anode catalyst layer and the cathode catalyst layer is not particularly limited as long as it is a material having proton conductivity and electrical insulation, but it may be a solid or gel that does not dissolve by fuel such as methanol. preferable. Specifically, organic polymers having strong acid groups such as sulfonic acid and phosphoric acid groups and weak acid groups such as carboxyl groups are preferred. Examples of the organic polymer include perfluorocarbon (Nafion (manufactured by DuPont)), carboxyl group-containing perfluorocarbon (Flemion (manufactured by Asahi Kasei)), polystyrene sulfonic acid copolymer, polyvinyl sulfonic acid copolymer, ionic liquid ( Room temperature molten salt), sulfonated imide, 2-acrylamido-2-methylpropanesulfonic acid (AMPS) and the like. In addition, when using the above-described carrier imparted with proton conductivity, the carrier does not necessarily require an electrolyte because the carrier conducts proton conduction.

  The thickness of the anode catalyst layer and the cathode catalyst layer is 0.2 mm in order to reduce the resistance of proton conduction and electron conduction, and to reduce the diffusion resistance of fuel (eg, aqueous methanol solution) or oxidant (eg, oxygen), respectively. The following is preferable. Moreover, in order to improve the output as the fuel cell stack, it is necessary to carry a sufficient catalyst, and therefore it is preferable that the thickness is at least 0.1 μm or more.

  The anode porous substrate and the cathode porous substrate are preferably made of a conductive material. For example, carbon paper, carbon cloth, metal foam, metal sintered body, metal fiber nonwoven fabric, and the like can be used. Metals used for metal foam, sintered metal, and non-woven fabric of metal fibers include noble metals such as Pt, Ru, Au, Ag, Rh, Pd, Os, Ir; Ni, V, Ti, Co, Mo, Fe And base metals such as Cu, Zn, Sn, W, and Zr; and oxides, carbides, nitrides, and carbonitrides of these noble metals or base metals. When the anode porous substrate and the cathode porous substrate are provided, the anode porous substrate is disposed on the anode current collecting layer side (the side opposite to the electrolyte membrane side) in the anode electrode, and the cathode porous substrate is The cathode electrode is disposed outside the unit cell (on the side opposite to the electrolyte membrane side).

  In the present specification, a composite of the electrolyte membrane and an anode electrode and a cathode electrode sandwiching the electrolyte membrane may be referred to as a “membrane electrode assembly (MEA)”.

(Anode current collector layer)
The anode current collecting layer (anode current collecting layer 205 in FIG. 3) has a function of transferring electrons to and from the anode electrode. In the present embodiment, the anode current collecting layer is a through-hole that is a part of a fuel flow path 208 for supplying fuel to the anode electrode and a product gas discharge flow path for discharging a product gas generated by a reaction at the anode electrode. Hole 206.

  Suitable materials used for the anode current collecting layer include carbon materials; conductive polymers; noble metals such as Au, Pt, Pd; Ti, Ta, W, Nb, Ni, Al, Cr, Ag, Cu, Zn, Metals such as Su; Si; nitrides, carbides and carbonitrides of these noble metals, metals or Si; and alloys such as stainless steel, Cu—Cr, Ni—Cr, and Ti—Pt. More preferably, it contains at least one element selected from the group consisting of Pt, Ti, Au, Ag, Cu, Ni and W. By including such an element, the specific resistance of the anode current collecting layer is reduced, so that the voltage drop due to the resistance of the anode current collecting layer can be reduced, and higher power generation characteristics can be obtained. In the case of using a metal having poor corrosion resistance in an acidic atmosphere such as Cu, Ag, Zn, etc., noble metals and metal materials having corrosion resistance such as Au, Pt, Pd, conductive polymers, conductive nitriding A material, a conductive carbide, a conductive carbonitride, a conductive oxide or the like can be used as the surface coating. Thereby, the lifetime of the unit cell and the fuel cell stack using the unit cell can be extended.

  In the present embodiment, the anode current collecting layer 205 has a through hole 206 penetrating in the layer thickness direction. Generated gas such as carbon dioxide generated at the anode electrode 203 becomes a bubble, and is discharged from the through hole 206 to the discharge channel 207 of the spacer 107 when it becomes large. Due to the through hole, the generated gas is discharged to the discharge flow path 207 at the shortest distance, so that the discharge efficiency of the generated gas can be improved.

  The cross-sectional shape of the through hole is not particularly limited, and can be, for example, a circle, an ellipse, a square, a triangle, or the like. The inner diameter of the through hole is preferably in the range of 10 μm to 1 mm. Moreover, it is preferable that two or more through holes are provided for one unit battery. In this case, the distance (pitch) between the through holes is preferably in the range of 100 μm to 10 mm. From the viewpoint of preventing leakage of fuel such as aqueous methanol solution, the inner diameter of the through hole is preferably less than 500 μm. Further, from the viewpoint of the discharge efficiency of the generated gas such as carbon dioxide, the inner diameter of the through holes is preferably 100 μm or more, and the distance between the through holes is more preferably less than 1 mm. The number of through holes and the cross-sectional area thereof are preferably determined in consideration of the electrical resistance of the anode current collecting layer, the contact area between the anode current collecting layer and the anode electrode, and the like. The through hole can be formed, for example, by providing a hole penetrating by etching or the like in a plate or foil made of the above-described material. When a plurality of through holes are provided, the plurality of through holes may communicate with each other.

  The inner wall surface of the through hole is preferably subjected to water repellent treatment. By providing the inner wall surface of the through hole with water repellency, it is possible to prevent defective discharge of the generated gas due to the through hole being blocked by a liquid such as fuel. The water repellent treatment of the inner wall surface of the through hole can be performed by applying a water repellent material containing a fluororesin or the like, plasma graft polymerization treatment, ion beam modification treatment, electron beam irradiation treatment, or the like.

  Further, as shown in FIG. 3, it is also preferable to fill the gas-liquid separation layer 209 in the through hole 206. By providing the gas-liquid separation layer 209, it is possible to prevent the fuel from leaking into the discharge channel 207 of the spacer 107. The gas-liquid separation layer 209 is made of a porous material that is impermeable to liquids such as water and aqueous methanol solution, is permeable to gas, and has gas-liquid separation ability. Further, the material constituting the gas-liquid separation layer 209 preferably has conductivity from the viewpoint of efficiently conducting electrons from the anode electrode 203 to the anode current collecting layer 205. As a material used for the gas-liquid separation layer 209, a mixture of a material having gas-liquid separation ability and a material having conductivity can be used. Examples of such a mixed material include a mixture of a fluorine-based polymer such as PTFE (Polytetrafluorethylene) or PVDF (Polyvinylidenefluoride) and acetylene black, ketjen black, amorphous carbon, carbon nanotube, carbon nanohorn, or the like.

  The fuel flow path is a flow path for supplying fuel to the anode electrode, and is formed separately from the through hole. Thereby, supply of fuel and discharge of product gas can be performed separately. As described above, the anode current collecting layer 205 has both functions of supplying fuel and discharging generated gas. This contributes to miniaturization, thinning, and weight reduction of the unit cell and consequently the fuel cell stack.

The shape of the fuel flow path is not particularly limited, and for example, the cross-sectional shape thereof is a quadrangular shape as shown in FIG. The fuel flow path can be configured as one or more grooves formed on the surface of the anode current collecting layer on the anode electrode side. The fuel flow path usually extends in the longitudinal direction of the unit cell (extends in parallel or substantially in parallel with the long side of the unit cell), and one end thereof is connected to a fuel tank or the like in which fuel is stored so that the anode current collecting layer The other end is sealed to prevent fuel leakage. The end of the fuel flow path and the fuel tank can be connected in any manner as long as the fuel does not leak. The width and cross-sectional area of the fuel flow path are preferably 0.1 to ¹ mm and 0.01 to ¹ mm ² , respectively. The width and cross-sectional area of the fuel flow path are preferably determined in consideration of the electrical resistance of the anode current collecting layer, the contact area between the anode current collecting layer and the anode electrode, and the like. The fuel supply method is not particularly limited as long as the fuel flow path is filled with liquid fuel, and is supplied by a pump, or supplied using the pressure of pressurized liquid in the cartridge. Examples thereof include a method and a method of feeding liquid by capillary force in the fuel flow path.

  The length of the region where the anode electrode and the anode current collecting layer are not in contact with each other is preferably less than 1 mm at the maximum in one unit cell. Further, the area where the anode electrode and the anode current collecting layer are in contact with each other is preferably 20% or more of the surface area on the anode current collecting layer side of the anode electrode. The same applies when another layer is interposed between the anode electrode and the anode current collecting layer.

  As in the unit cell 103 shown in FIG. 3, the fuel permeable layer 210 is formed between the anode electrode 203 and the anode current collecting layer 205 so as to cover the surface on the anode electrode 203 side of the fuel flow path 208. Is preferably provided. The fuel permeable layer is a layer for controlling the flow rate of the fuel supplied from the fuel flow path 208 to the anode electrode 203. The fuel permeable layer is made of, for example, a fluorine-based polymer such as PTFE or PVDF, a synthetic resin such as silicone resin, or a polymer material such as polymethyl methacrylate, polyhydroxyethyl methacrylate, polydimethylacrylamide, polyglycerol methacrylate, or polyvinylpyrrolidone. From a film prepared using seeds or two or more kinds, or a layer (film) comprising a plurality of through-holes made of the polymer material and penetrating in the thickness direction having a hole diameter uniformly controlled by casting or the like Can be configured.

  In the present invention, the unit cell includes a cathode electrode, an electrolyte membrane, an anode electrode, and an anode current collecting layer in this order. However, in addition to these, other unit members may be included as necessary. Other constituent members are not particularly limited, and examples thereof include a cathode current collecting layer, a separator, and the fuel permeable layer.

(Spacer)
The spacer (the spacer 107 in FIG. 3) is a member constituting a spacer layer disposed between the fuel cell layers. Referring to FIGS. 2 and 3, for example, first spacer layer 115 is arranged between first fuel cell layer 110 and second fuel cell layer 120. The spacer 107 constituting the first spacer layer 115 is composed of the anode current collecting layer 205 of the unit cell 103 constituting the first fuel cell layer 110 and the cathode electrode 204 of the unit cell 103 constituting the second fuel cell layer 120. It arrange | positions so that it may touch. By interposing such a spacer layer, the two fuel cell layers are arranged apart from each other, and a space portion (the space portion is formed between the spacers) between the two fuel cell layers. Including the gap 140). Such a space improves air (oxygen) supply to the cathode electrode of the unit cell located inside the fuel cell stack. In the present embodiment, the spacer 107 includes a discharge flow path 207 that is a part of a generated gas discharge flow path for guiding the generated gas generated by the reaction at the anode electrode to a gas aggregation section described later.

  The material constituting the spacer is not particularly limited as long as it maintains a strength sufficient to ensure a space between the fuel cell layers even when an external force is applied to the fuel cell stack, but is preferably a conductive material. By using the conductive material, the fuel cell layers can be connected in series without using any other external wiring, which is advantageous for miniaturization of the fuel cell stack. As the material constituting the spacer, it is preferable to use the same material as that of the anode current collecting layer. For example, carbon material; conductive polymer; noble metal such as Au, Pt, Pd; Ti, Ta, W, Nb, Ni , Al, Cr, Ag, Cu, Zn, Su, etc .; Si; nitrides, carbides, carbonitrides, etc. of these noble metals, metals or Si; and stainless steel, Cu—Cr, Ni—Cr, Ti—Pt Examples of such an alloy can be given. More preferably, it contains at least one element selected from the group consisting of Pt, Ti, Au, Ag, Cu, Ni and W. By including such an element, the specific resistance of the spacer is reduced, so that a voltage drop due to the resistance of the spacer can be reduced and higher power generation characteristics can be obtained. In the case of using a metal having poor corrosion resistance in an acidic atmosphere such as Cu, Ag, Zn, etc., noble metals and metal materials having corrosion resistance such as Au, Pt, Pd, conductive polymers, conductive nitriding A material, a conductive carbide, a conductive carbonitride, a conductive oxide or the like can be used as the surface coating. As a result, the life of the fuel cell, and thus the fuel cell stack, can be extended.

  In the present embodiment, the shape of the spacer 107 makes it possible to secure a space where air (oxygen) is supplied between the fuel cell layers, and the discharge channel 207 formed in the spacer 107 and the anode adjacent to the spacer 107. There is no particular limitation as long as it can communicate with the through-hole 206 of the current collecting layer 205, but in order to ensure a uniform thickness of the space portion and increase the volume of the space portion, a unit cell adjacent to the spacer is provided. It is preferable that at least one end of the spacer has a strip shape having a long side length that can protrude from an adjacent fuel cell layer, particularly a column shape. The columnar cross-sectional shape is not particularly limited, and can be, for example, elliptical or rectangular. When the spacer 107 is made of a conductive material and the spacer 107 plays a role of electrical connection, the shape of the spacer 107 is preferably a rectangular parallelepiped. By making the spacer 107 a rectangular parallelepiped shape, the spacer 107 and the unit cell of the fuel cell layer adjacent to the spacer 107 can be brought into contact with each other, so that the electrical contact resistance can be reduced. In addition, by making the shape of the spacer a rectangular parallelepiped, the through hole of the anode current collecting layer and the discharge flow path of the spacer can be easily communicated with no gap, and the leakage of the generated gas can be effectively prevented. .

  When the spacer has a strip shape (in particular, a rectangular parallelepiped shape) having a long side and a short side, the width of the spacer (the length of the short side) covers the through-hole formed in the anode current collecting layer. There is no particular limitation as long as the size can be reduced, but 0.5 mm or more is preferable to maintain the structural strength of the fuel cell stack, and 5 mm or less to facilitate oxygen supply to the space. Preferably there is. The thickness of the spacer (the thickness of the spacer layer) is preferably 0.1 mm or more in order to facilitate oxygen supply into the space formed by the spacer, and 5 mm or less in order to prevent the fuel cell stack from becoming large. Preferably there is. The thickness of the spacer (the thickness of the spacer layer) is more preferably 0.2 mm to 1 mm.

  The number of spacers in one spacer layer is not particularly limited as long as the space can be secured, but is 2 or more in order to stably secure the space even when an external force is applied to the fuel cell stack. Is preferred.

  Further, in order to reduce the discharge resistance of the generated gas at the anode electrode, the contact area between the spacer and the spacer on the spacer side surface of the fuel cell layer adjacent to the spacer is preferably 20% or more of the entire spacer side surface. In order to reduce the resistance of oxygen supply into the space, it is preferably 80% or less.

  In the present embodiment, the spacer 107 includes a discharge flow path 207 that is a part of a generated gas discharge flow path for guiding the generated gas generated by the reaction at the anode electrode to a gas aggregation section described later. In each fuel cell included in the fuel cell stack of the present embodiment, the spacer is a through hole formed in the anode current collecting layer of all unit cells constituting the fuel cell layer and the discharge of the spacer with respect to the fuel cell layer. Typically, the discharge channel of the spacer is disposed so as to be located immediately below the spacer side opening of the through hole so as to communicate with the channel.

The shape of the discharge flow path 207 formed in the spacer 107 can communicate with the through hole 206 of the anode current collecting layer 205 adjacent to the spacer 107, and extends to the end of the spacer 107 connected to the gas collecting portion. There is no particular limitation as long as it is, for example, 1 formed on one surface of the spacer 107 (surface on the side in contact with the anode current collecting layer) extending in the longitudinal direction of the spacer (extending in parallel or substantially parallel to the long side) 1 or It can be composed of two or more grooves. In this case, the cross-sectional shape of the groove is not particularly limited, but may be, for example, a square shape. The position of the groove on the surface in contact with the anode current collecting layer is not particularly limited, and can be, for example, the center of the surface or the vicinity of the center. Further, by using a hollow spacer and providing a communication hole for communicating the through hole 206 and the hollow portion of the spacer at the joint between the hollow spacer and the through hole 206 of the anode current collecting layer 205, the hollow space of the spacer is reduced. The part and the communication hole can be used as a discharge channel. The groove or the end of the hollow portion at the end opposite to the side connected to the gas collecting portion is sealed so that the generated gas does not flow out from the end. The width and cross-sectional area of the discharge channel 207 are preferably 0.1 to ¹ mm and 0.01 to ¹ mm ² , respectively. When a conductive material is used for the spacer, it is preferable to determine the width and cross-sectional area of the discharge channel 207 in consideration of the electrical resistance of the spacer 107, the contact area between the spacer 107 and the anode current collecting layer 205, and the like. The discharge channel 207 can be formed by etching, pressing, cutting, or the like.

  Moreover, it is preferable that the discharge flow path 207 includes a catalyst for burning the organic compound component in the product gas discharged from the through hole 206 therein. By providing such a catalyst, an organic compound contained in a generated gas such as discharged carbon dioxide can be reacted with oxygen in the air and burned. Thereby, the discharge amount of the organic compound mainly composed of methanol vapor to the outside of the fuel cell system can be reduced. Moreover, by transmitting the heat generated during combustion to the unit cell, the catalytic reaction can be activated and the power generation efficiency can be improved. Pt fine particles are preferably used as the organic compound combustion catalyst, and the catalyst is preferably supported on a carrier. In order to improve heat resistance, it is preferable to use a porous body such as a metal or metal oxide as the carrier.

  When the spacer discharge channel 207 is composed of one or two or more grooves formed on the surface of the spacer 107 on the side in contact with the anode current collecting layer 205, the unit battery 103 blocks the opening of the groove. The portion not in contact (the portion in contact with the gap 130 formed between the unit cells 103) is sealed by the gas permeation prevention layer 150 so that the generated gas generated at the anode electrode does not leak into the fuel cell stack ( 2 and 3). The gas permeation preventive layer is, for example, the same or equivalent metal as the material constituting the spacer, as well as synthetic rubber such as nitrile rubber, silicone rubber, acrylic rubber, ethylene butadiene rubber, fluorine rubber, ethylene propylene rubber, natural rubber, etc. In view of chemical resistance, heat resistance, and sealing performance with the spacer, it is preferable to use the same or equivalent metal as the material constituting the spacer.

  Here, the spacer 107 is preferably integrated with the anode current collecting layer 205 adjacent to the spacer 107. That is, it is preferable that the fuel cell layer and the spacer layer constituting the unit of the fuel cell of the fuel cell stack are integrated. The term “integrated” refers to a state where no separation occurs even if pressure is not applied from the outside, and specifically refers to a state where they are joined by a chemical bond, an anchor effect, an adhesive force, or the like. By integrating the spacer 107 and the anode current collecting layer 205, the air density of the joint surface between the spacer 107 and the anode current collecting layer 205 is improved, and it is possible to prevent the generated gas from leaking from the joint surface. it can. As a result, it is possible to prevent the product gas from leaking from the joint surface to the vicinity of the cathode, so that it is possible to prevent the oxygen supply from being hindered due to the leak of the product gas and maintain a high output of the fuel cell stack. Examples of a method for integrating the spacer 107 and the anode current collecting layer 205 include adhesion using an adhesive such as a thermosetting resin, diffusion bonding, ultrasonic bonding, and laser welding. Similarly, considering the mechanical stability and electrical connectivity of the fuel cell stack, the fuel cells constituting the fuel cell stack are also preferably integrated. When using conductive spacers and connecting the fuel cells in series, the fuel cells can be integrated using, for example, a conductive adhesive.

<Gas Consolidation Department>
As shown in FIG. 1, the fuel cell system 100 of the present embodiment includes a gas aggregating unit 102 for aggregating the generated gas generated by the power generation of the unit cells 103 of the fuel cell stack 101. The aggregated generated gas is discharged to the outside of the fuel cell system 100 from the end opening (gas exhaust port 106) of the generated gas guiding path 105 connected to the opening 104 of the gas aggregating section 102.

  The configuration of the gas aggregating unit 102 is particularly as long as the generated gas generated by the power generation of the unit cell 103 of the fuel cell stack 101 can be aggregated and the aggregated generated gas can be discharged to the outside of the fuel cell system 100. Although not limited, it can be comprised from the hollow body which has a cavity part inside like the fuel cell system 100 shown by FIG. In this case, the hollow portion becomes a part for collecting the generated gas, and the opening 104 provided on the outer surface of the gas collecting portion is communicated with the hollow portion. The outer shape of the gas collecting part is not particularly limited. Instead of discharging the generated gas from the end opening (gas discharge port 106) of the generated gas guiding path 105, the generated gas may be discharged directly from the opening without providing the generated gas guiding path. The position of the opening in the gas concentrating portion is not particularly limited. Particularly, when the generated gas is discharged directly from the opening, it is necessary that the discharged generated gas is not taken into the fuel cell stack. For example, the opening is directed in a direction different from the direction in which the fuel cell stack is located.

  Although the material which comprises the gas concentration part 102 will not be specifically limited if it has a difficult gas permeability, It is preferable to use a polymer base material, an inorganic base material, and a metal base material. Furthermore, from the viewpoint of being lightweight and insulating, silicon resin, polycarbonate resin, phenol resin, polyolefin resin, epoxy resin, polyethylene terephthalate resin, polypropylene resin, polyimide resin, polyamide resin, polyamideimide resin, polyether ether ketone resin It is more preferable to use a material made of any of the above.

  In the fuel cell system 100 of the present embodiment, the gas collecting unit 102 is connected to the end portions of all the spacers 107 included in the fuel cell stack 101 where the discharge flow passages 207 are formed to the end. As a result, the hollow portion of the gas concentrating portion 102 and the anode electrodes 203 of all the unit cells 103 included in the fuel cell stack 101 are provided inside the fuel cells constituting the fuel cell stack 101 for discharging the generated gas. It communicates with a flow path. As a method of connecting the gas collecting portion and the spacer, for example, a hole for inserting the spacer is provided on the side surface of the hollow body that is the gas collecting portion, the spacer is inserted into the hole, and the outer periphery of the connecting portion is sealed with a sealing material The method of doing is mentioned. In addition, in the electronic device on which the fuel cell stack is mounted, a gas collecting part including a flexible wall surface (for example, rubber) is formed in advance, and the spacer of the fuel cell stack is pierced into the flexible wall surface, You may make it seal the outer periphery of a connection part. In this case, the fuel cell system is constructed in the electronic device. In the present embodiment, it is not necessary for one gas collecting part to be connected to all the spacers provided in the fuel cell stack. For example, you may make it provide a gas concentration part for every fuel cell which comprises a fuel cell stack. In this case, typically, one gas collecting portion is connected to all the spacers of one fuel cell, and the same number of gas collecting portions as the number of fuel cells included in the fuel cell stack are provided. In the present embodiment, the fuel cell stack has at least one unit of fuel cell, and the gas concentrating portion is connected to the end portions of all the spacers of the at least one spacer layer of the fuel cell stack. It only has to be done.

  The fuel cell system of the present invention may have one or two or more gas collecting units, but preferably all of the gas collecting units are fuel cells, such as the fuel cell system 100 shown in FIG. It is preferable that the outer surface of the stack is disposed adjacent to one side surface. Thereby, many air intake surfaces to the fuel cell stack can be secured. In addition, when the fuel cell stack is mounted on an electronic device, it is preferable that the installation surface of the gas collecting portion is selected from the outer surface of the fuel cell stack that does not become the air intake surface of the fuel cell stack. As a result, since the gas concentrating portion does not hinder the air supply to the fuel cell stack, it is possible to provide a stable fuel cell system with a higher output density.

  As shown in FIG. 1, the fuel cell system 100 according to the present embodiment is connected to the opening 104 of the gas collecting unit 102 and adjusts the discharge position of the generated gas collected in the gas collecting unit in the fuel cell system. The hollow product gas guide path 105 is provided. In this case, the opening on the side opposite to the opening 104 side of the gas concentrating portion 102 in the generated gas guiding path 105 is a generated gas discharge port (gas discharge port 106 in FIG. 1). Such a product gas guiding path is particularly advantageous in adjusting the discharge position of the product gas in an electronic device including a fuel cell system. However, it is also possible to discharge the generated gas directly from the opening (the opening 104 in FIG. 1) of the gas collecting part. The material constituting the product gas guiding path can be the same as that of the gas collecting part. Further, the length, the outer shape, and the cross-sectional shape of the product gas guide path are not particularly limited, and the length, the outer shape, and the like are determined according to a desired product gas discharge port position.

  The product gas guide path is provided with a filter (hazardous component removal filter) for removing harmful components in the exhausted product gas at the opening (gas discharge port) opposite to the opening side of the gas collecting portion. It may be. By providing such a filter, even if a by-product that is harmful due to the reaction is generated and reaches the gas discharge port via the gas collecting part, it is removed by the filter, so that safety is improved. In addition, it is advantageous to configure the generated gas guide path so that the gas discharge port is located at the outer edge of the electronic device including the fuel cell system because the filter can be easily replaced.

  Further, the inner wall surface of the generated gas guiding path may be subjected to water repellent treatment. Even when the warm product gas from the anode electrode (product gas may contain, for example, methanol vapor as a fuel) is cooled in the discharge channel and condensed on the inner wall surface of the product gas guide channel, Since it is easy to flow to the lower part, it is possible to prevent liquid droplets from leaking to the outside when the electronic apparatus is in use. The water repellent treatment of the inner wall surface of the generated gas guiding path can be the same as the water repellent treatment of the through hole provided in the anode current collecting layer described above.

  The direction in which the product gas guiding path extends is not particularly limited, but preferably extends in a direction different from the direction in which the fuel cell stack is located. In addition, the product gas guiding path is provided in the gas collecting section so that the gas discharge port of the product gas guiding path faces upward when the fuel cell system is used or when the electronic device including the fuel cell system is used. It is preferable.

<< Second Embodiment >>
FIG. 4 is a cross-sectional view showing another preferred example of the fuel cell stack constituting the fuel cell system of the present invention. FIG. 4 is a cross-sectional view showing only a part of the fuel cell stack 201 according to the present embodiment, as in FIG. 3. The fuel cell stack 201 is a first cell in which a plurality of strip-shaped unit cells 303 having long sides and short sides are arranged on the same plane so that gaps 330 are formed between the unit cells 303. A first spacer layer in which a fuel cell layer 310 and a plurality of strip-shaped spacers 407 having a long side and a short side are arranged on the same plane so that a gap is formed between the spacers 507; The second fuel cell layer 320 having the same structure as the first fuel cell layer 310 and the second spacer layer (not shown in FIG. 4) having the same structure as the first spacer layer are arranged in this order. Is laminated. The external shapes of the unit battery 303 and the spacer 507 used are the same as those in the first embodiment.

  The first fuel cell layer 310 and the first spacer layer adjacent to the first fuel cell layer 310 intersect such that the unit cell 303 included in the first fuel cell layer 310 and the spacer 507 included in the first spacer layer intersect ( More specifically, they are stacked so as to be orthogonal or substantially orthogonal. The same applies to the first spacer layer and the second fuel cell layer 320 adjacent thereto, and the second fuel cell layer 320 and the second spacer layer adjacent thereto.

  As shown in FIG. 4, the unit cell 303 constituting the first fuel cell layer 310 and the second fuel cell layer 320 includes a cathode electrode 404, an electrolyte membrane 402, an anode electrode 403, and an anode current collecting layer 405. Prepare in order. More specifically, the unit cell 303 includes an electrolyte membrane 402, an anode electrode 403 disposed on one surface of the electrolyte membrane 402, a cathode electrode 404 disposed on the other surface of the electrolyte membrane 402, and an anode electrode. The anode current collecting layer 405 is disposed in contact with the surface opposite to the surface facing the electrolyte membrane 402 of 403.

  The first fuel cell layer 310 is arranged such that the spacer 507 constituting the first spacer layer and the anode current collecting layer 405 of the unit cell 303 constituting the first fuel cell layer 310 are in contact with each other. All the unit cells 303 that are stacked on top and constitute the first fuel cell layer 310 are arranged so that the anode electrode 403 side faces the first spacer layer. The first fuel cell layer 310 and the first spacer layer form one “fuel cell” unit in the fuel cell stack 201. All the unit cells 303 constituting the second fuel cell layer 320 are arranged so that the cathode electrode 404 faces the first spacer layer. Similarly, all the unit cells 303 constituting the second fuel cell layer 320 are arranged so that the anode electrode 403 side faces the second spacer layer, and the second fuel cell layer 320 and the second fuel cell layer 320 The spacer layer forms one “fuel cell” unit in the fuel cell stack 201.

  Here, in the fuel cell stack 201 according to the present embodiment, the generated gas generated at the anode electrode 403 of all the unit cells 303 included in the fuel cell stack 201 can be guided to the gas collecting unit (not shown in FIG. 4). As in the first embodiment, for each “fuel cell” unit, the hollow portion of the gas concentrating unit and the anode electrode 403 of all the unit cells 303 of the fuel cell layer of each fuel cell are communicated. The “product gas discharge channel” is provided inside. In the present embodiment, referring to FIG. 4, the generated gas discharge flow path has a fuel cell layer (each of the first fuel cell layer 310 and the second fuel cell layer 320) of each fuel cell. The discharge channel 407 is formed in the anode current collecting layer 405 of all the unit cells 303. The discharge channel 407 extends to the end of the unit cell 303, and the end of the unit cell 303 in which the discharge channel 407 is formed is connected to the gas collecting unit. Thereby, the cavity part which a gas concentration part has, and the anode electrode 403 of all the unit cells 303 which the fuel cell layer of each fuel cell has are connected. Each unit cell 303 is arranged so that at least one end protrudes from the adjacent spacer layer so that it can be connected to the gas collecting part. Further, the end of the discharge channel 407 is sealed at the end of the unit battery 303 opposite to the side connected to the gas collecting portion so that the generated gas does not leak.

  FIG. 5 is a diagram schematically showing a part of the anode current collecting layer used in the fuel cell stack of the present embodiment. FIG. 5A is a top view (showing the anode electrode side surface) and FIG. b) is a perspective view. As shown in FIG. 5, the anode current collecting layer 405 in this embodiment includes a fuel channel 408 for supplying fuel to the anode electrode of the unit cell, and an anode formed separately from the fuel channel 408. And a discharge channel 407 as a product gas discharge channel for discharging the product gas generated by the reaction at the electrode. The structure of the fuel flow path 408 is the same as that of the first embodiment.

Similarly to the fuel flow path 408, the discharge flow path 407 extends in the longitudinal direction of the anode current collecting layer 405 formed on the joint surface with the anode electrode (extends in parallel or substantially parallel to the long side). It can consist of grooves. As a result, in the unit cell 303, the discharge flow path 407 comes into contact with the anode electrode 403, and the generated gas generated at the anode electrode 403 can be discharged to the discharge flow path 407. The width and cross-sectional area of the discharge channel 407 are preferably 0.1 to ¹ mm and 0.01 to ¹ mm ² , respectively. In the anode current collecting layer 405, the discharge channel 407 can be arranged in parallel or substantially in parallel with the fuel channel 408.

  As described above, in the present embodiment, each unit cell 303 is connected to the gas collecting portion so that the discharge flow path 407 and the hollow portion of the gas collecting portion communicate with each other at one end thereof. Therefore, the discharge channel 407 extends to the end of the anode current collecting layer 405 that is connected to the gas concentrating portion, and at the opposite end, the discharge channel of the discharge channel is prevented from leaking. The ends are sealed. Similarly, the fuel flow path 408 extends to one end of the anode current collecting layer so that it can be connected to a fuel tank or the like containing fuel, and is sealed so that fuel leakage does not occur at the other end. . Here, as shown in FIG. 5, the end (the end on the side where the discharge flow path is formed to the end face) connected to the gas collecting part of the anode current collecting layer and the fuel are accommodated. It is preferably different from the end portion on the side connected to the fuel tank or the like (the end portion on the side where the fuel flow path is formed up to the end face). With such a configuration, it is possible to prevent the fuel from leaking from the fuel flow path 408 into the gas concentration section when the discharge flow path 407 and the gas concentration section are connected.

  The fuel supply method is not particularly limited as long as the fuel flow path 408 is filled with liquid fuel, and a method of feeding with a pump or a method of feeding using the pressure of the pressurized liquid in the cartridge. And a method of feeding liquid by capillary force in the fuel flow path.

  In this embodiment, the unit cell 303 is formed between the anode electrode 403 and the anode current collecting layer 405 so as to cover the surface on the anode electrode 403 side of the fuel flow path 408, as in the first embodiment. The fuel permeation layer 410 is provided (see FIG. 4). The liquid fuel supplied to the fuel flow path 408 passes through the fuel permeable layer 410 and is consumed at the anode electrode 403. Generated gas such as carbon dioxide generated at the anode electrode 403 becomes bubbles and is discharged from the discharge flow path 407 when it becomes larger. The generated gas discharged from the discharge flow path 407 is collected by the gas collecting unit, and discharged from the opening of the gas collecting unit or the gas discharge port of the generated gas guiding path to the outside of the fuel cell system.

  As shown in FIG. 4, it is also preferable to provide a gas-liquid separation layer 409 in the discharge flow path 407. By providing the gas-liquid separation layer 409, it is possible to prevent the fuel from leaking into the discharge channel 407. The gas-liquid separation layer 409 is made of a porous material that is impermeable to liquids such as water and aqueous methanol solution, is permeable to gas, and has gas-liquid separation ability. The material constituting the gas-liquid separation layer 409 preferably has conductivity from the viewpoint of efficiently conducting electrons from the anode electrode 403 to the anode current collecting layer 405. As a material used for the gas-liquid separation layer 409, a mixture of a material having gas-liquid separation ability and a material having conductivity can be used. Examples of such a mixed material include a mixture of a fluorine-based polymer such as PTFE (Polytetrafluorethylene) or PVDF (Polyvinylidenefluoride) and acetylene black, ketjen black, amorphous carbon, carbon nanotube, carbon nanohorn, or the like.

  In the case where the gas-liquid separation layer is provided in the discharge flow path, the gas-liquid separation layer may be filled over the entire depth direction of the discharge flow path (the thickness direction of the anode current collecting layer). What is necessary is just to be formed so that it may touch. Further, the gas-liquid separation layer may be formed on the surface of the anode current collecting layer 405 so as to block the opening of the discharge channel 407. By providing the gas-liquid separation layer, defective discharge of the generated gas to the outside due to the penetration of fuel into the discharge flow path 407 can be prevented, and stable output characteristics of the fuel cell stack can be obtained. In addition, since the fuel can be prevented from leaking out of the fuel cell stack through the discharge channel 407, the reliability of the fuel cell stack can be improved.

  Also in this embodiment, it is not necessary for one gas concentrating unit to be connected to all unit cells included in the fuel cell stack. For example, you may make it provide a gas concentration part for every fuel cell which comprises a fuel cell stack. In this case, typically, one gas concentration unit is connected to all unit cells of one fuel cell, and the same number of gas concentration units as the number of fuel cells included in the fuel cell stack are provided. Further, in the present embodiment, the fuel cell stack has at least one unit of fuel cell, and the gas concentrating unit is provided at the end of all unit cells of at least one fuel cell layer included in the fuel cell stack. Need only be connected.

  Other configurations in the fuel cell system of the present embodiment and modifications of the fuel cell system can be the same as those in the first embodiment.

  Further, as a preferred modification of the present embodiment, a configuration in which the fuel cell stack does not have a spacer can be given. In this case, the fuel cell stack includes one or more fuel cell layers in which two or more unit cells are arranged on the same plane, preferably with a gap. When the fuel cell stack includes two or more fuel cell layers, these fuel cell layers include the anode of the unit cell constituting one fuel cell layer, and the cathode of the unit cell constituting the fuel cell layer adjacent thereto. It is laminated so that a space is preferably formed between the fuel cell layers so as to face the electrodes. For example, a hole for inserting one end of each unit cell constituting the fuel cell layer is provided in the side surface of the hollow body that is a gas collecting part, as many as the number of unit cells constituting the fuel cell stack, By inserting the unit cell into the hole and sealing the outer periphery of the connecting portion with a sealing material, it is possible to construct a fuel cell system having no spacer and having a space between the fuel cell layers. In this case, one fuel cell layer and the fuel cell layer adjacent thereto are electrically connected in series via an external wiring, for example. The shape of the unit battery can be the same as in the first and second embodiments. When the fuel cell stack as described above is used, the internal structure of the unit cell can be the same as that shown in FIG.

<< Third Embodiment >>
FIG. 6 is a perspective view schematically showing a preferred example (a notebook personal computer for portable use) of an electronic apparatus including the fuel cell system of the present invention. An electronic apparatus (notebook type personal computer) 600 shown in FIG. 6 has a portion (a battery accommodating chamber formed of a hollow portion) for mounting the fuel cell system or the fuel cell stack according to the present invention. In addition, a fuel cell system or a fuel cell stack 601 can be mounted. As the fuel cell system and the fuel cell stack to be mounted, for example, those shown in FIGS. 1 and 2 can be used, respectively. However, as will be described later, when the generated gas induction path is provided in the electronic device, the fuel cell system to be mounted may not have the generated gas induction path. The gas concentrating portion constituting the fuel cell system of the present invention is typically joined in advance to a fuel cell stack to be mounted, and an electronic device equipped with the fuel cell system by incorporating such a fuel cell system into the above-described portion. Equipment is built. However, a fuel cell system may be built in an electric device by providing a gas collecting part in the electronic device and incorporating the fuel cell stack in the above-mentioned part.

  As shown in FIG. 6, the electronic device 600 preferably includes a generated gas guide path 605 connected to an opening of a gas collecting unit included in a fuel cell system to be mounted. The generated gas guiding path 605 is formed, for example, by forming a hollow portion inside one of the constituent members constituting the electronic apparatus 600 (in the example shown in FIG. 6, the member provided with the display 602). can do. The part-side opening for mounting the fuel cell system or the fuel cell stack 601 of the generated gas guiding path 605 includes the opening and the opening part of the gas collecting part when the fuel cell system is mounted in the part. It is placed in a connectable position. A generated gas such as carbon dioxide discharged from the fuel cell system or the fuel cell stack 601 mounted on the electronic device 600 passes through the generated gas guiding path 605 and is discharged from the gas discharge port 606 to the outside of the electronic device 600. Thus, the generated gas generated at the anode electrode of each unit cell of the fuel cell stack can be discharged outside the electronic device 600 without being mixed with the air at the cathode electrode. It is possible to prevent a decrease in output due to a decrease in pressure. In addition, it is possible to prevent a decrease in output due to an internal current that occurs when methanol water vapor contained in the separated carbon dioxide flows into the cathode.

  Thus, when the fuel cell system of the present invention is mounted on an electronic device, or when the fuel cell stack is mounted on an electronic device and an electronic device including the fuel cell system of the present invention is constructed, the electronic device of the present invention is used. The device preferably includes a battery storage chamber that stores the fuel cell system or the fuel cell stack, and an opening that communicates the inside of the battery storage chamber with the outside of the electronic device is formed on the surface that forms the battery storage chamber. It is preferable to be provided. More specifically, a preferable example of the battery housing chamber is formed such that at least one surface of the battery housing chamber faces the outside of the electronic device inside any of the constituent members constituting the electronic device. And the said opening is formed in the surface which faces this electronic device exterior, or the said surface does not have a wall surface. More preferably, from the viewpoint of improving air supply efficiency, the battery housing chamber has a plurality of the above-described openings and / or two or more side surfaces not having a wall surface (refer to FIG. 6 for the latter). Such a side surface having no wall surface can be used as an entrance for mounting the fuel cell system or the fuel cell stack, and therefore it is preferable to have at least one side surface having no wall surface. For example, a slit-like or lattice-like cover is preferably provided on the side surface having no wall surface so that the mounted fuel cell system or fuel cell stack does not touch the user's hand. As described above, when the electronic device includes a battery housing chamber, the gas concentration part is a side surface of the battery housing chamber for mounting the fuel cell system or the fuel cell stack among the outer surfaces of the fuel cell stack. Thus, it is preferable to install the fuel cell stack adjacent to an outer surface which is located on a side surface other than the side surface having the opening or the side surface having no wall surface. In the electronic device including the fuel cell system shown in FIG. 6, air supply is performed on a portion for mounting the fuel cell system or the fuel cell stack on two lateral surfaces (two air supply surfaces shown in FIG. 6). The gas concentrating portion is provided adjacent to the outer surface of the fuel cell stack that is not located on the two air supply surface sides. Thereby, it becomes possible to install a gas concentration part, without inhibiting the route of the air supply from the outside.

The position of the generated gas guiding path 605 in the electronic device and the position of the gas outlet 606 located at the end of the generated gas guiding path 605 in the electronic apparatus are not particularly limited, and are set to a desired position according to the type of the electronic apparatus. For example, the gas discharge port is preferably arranged at the following position in the electronic apparatus.
(I) The gas discharge port is located as far as possible from an opening (air supply surface) for supplying air to the fuel cell stack, which is formed on the side surface of the portion for mounting the fuel cell system or fuel cell stack. It is preferable to provide it. As a result, it is possible to suppress a decrease in output due to mixing of the product gas from the anode electrode in the air supplied to the cathode electrode.
(Ii) It is preferable that the gas discharge port is disposed at the outer edge of the electronic device. Accordingly, when the above-described filter is provided at the gas discharge port, the filter can be easily replaced.
(Iii) It is preferable that the gas outlet is arranged in a place where the user of the electronic device does not feel uncomfortable during the use. For example, it is preferable to provide a gas discharge port on the back side of the surface facing the user in the electronic device to be used, such as a display of the electronic device.
(Iv) It is preferable to arrange the gas discharge port at a position above the fuel cell stack when the electronic device is used. As a result, even when the warm product gas from the anode electrode is cooled by the product gas guide path and condensed on the inner wall surface, the liquid droplets are guided to the lower part along the inner wall surface. It is possible to prevent liquid droplets from leaking outside the electronic apparatus.

  FIG. 7 is a perspective view schematically showing another preferred example (cellular phone) of an electronic device provided with the fuel cell system of the present invention, FIG. 7 (a) is a side view, and FIG. 7 (b) is a rear view. It is. An electronic apparatus (mobile phone) 700 shown in FIG. 7 has a portion for mounting the fuel cell system or fuel cell stack according to the present invention, and the fuel cell system or fuel cell stack 701 is mounted on the portion. It is possible. Similarly to the electronic device 600 shown in FIG. 6, a generated gas guide path 705 is provided in the electronic device, and the end thereof is a gas discharge port 706.

  FIG. 8 is a diagram schematically showing a fuel cell system 701a (including a product gas guiding path 705) provided in the electronic device 700 shown in FIG. 7, and FIG. 8 (a) is a rear view (FIG. 7 (b)). FIG. 8B is a side view (viewed from the same direction as FIG. 7A). As shown in FIG. 8, the fuel cell stack 701b constituting the fuel cell system 701a includes a plurality of strip-shaped unit cells 803 having a long side and a short side on the same plane as in the first embodiment. In addition, a fuel cell layer arranged so that a gap is formed between the unit cells 803 and a plurality of strip-shaped spacers 807 having a long side and a short side are arranged on the same plane. The spacer layers arranged so as to form a gap therebetween are alternately stacked, and the spacer 807 has a discharge channel 907 communicating with the through hole of the anode current collecting layer. In addition, the fuel cell system 701a includes a gas collecting portion 802 connected to each spacer 807, and the gas collecting portion 802 and the discharge flow path 907 of the spacer 807 are in communication. In addition, a generated gas guiding path 705 is connected to an opening communicating with the hollow portion of the gas collecting portion 802.

  In the electronic device 700 including the fuel cell system, the generated gas generated at the anode electrode of the unit cell 803 is collected in the gas collecting unit 802 through the discharge flow path 907 formed in the spacer 807, and the electrons are discharged from the gas discharge port 706. It is discharged outside the equipment.

  In the electronic device 700 shown in FIG. 7, a total of four surfaces including three horizontal surfaces and one lower surface are air supply surfaces (see FIG. 8A), and the gas concentrating unit 802 includes the fuel cell stack 701b. It is provided on the upper surface side (the surface side that does not become the air supply surface). Thereby, it becomes possible to install a gas concentration part, without inhibiting the route of the air supply from the outside.

  Also in the electronic device 700 shown in FIG. 7, the gas discharge port 706 is preferably arranged at the above-described preferable position in the electronic device 700. More preferably, the gas discharge port 706 is provided on the back side (the surface shown in FIG. 7B) of the display provided at the uppermost part and the front surface of the electronic device. Accordingly, when the user uses the electronic device, the gas discharge port can be prevented from being blocked when the user holds the electronic device, and the user can discharge from a place where the user does not feel uncomfortable.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited to these.

<Example 1>
A fuel cell system was produced according to the following procedure.

(1) Production of membrane electrode composite First, Nafion (registered trademark) 117 (manufactured by DuPont) having a width of 25 mm x a length of 25 mm and a thickness of about 175 µm was prepared as an electrolyte membrane. Next, catalyst-carrying carbon particles (TEC 66E50 manufactured by Tanaka Kikinzoku Co., Ltd.) composed of Pt particles, Ru particles and carbon particles having a Pt-carrying amount of 32.5% by mass and a Ru-carrying amount of 16.9% by mass, Alcohol solution (manufactured by Aldrich) containing 1% Nafion (registered trademark), isopropanol, and alumina balls are placed in a Teflon container at a mass ratio of 0.5: 1.5: 1.6: 100, An anode catalyst paste was prepared by mixing for 50 minutes at 500 rpm using a stirrer.

  A cathode catalyst paste was prepared in the same manner as the anode catalyst paste, except that catalyst-supported carbon particles (TEC10E50E manufactured by Tanaka Kikinzoku Co., Ltd.) composed of Pt particles and carbon particles having a Pt support amount of 46.8% by mass were used. .

Subsequently, as an anode electrode substrate (anode porous substrate), carbon paper (made by SGL Carbon Co., Ltd.) having an outer shape of 23 mm × 23 mm and water-repellent treatment with a layer made of a fluorine-based resin and carbon particles on one side: 25BC), a square-shaped opening having a width of 23 mm and a length of 23 mm is formed on the surface of the carbon paper that has been subjected to the water-repellent treatment so that the amount of the catalyst supported on the anode catalyst paste is 2 mg / cm ^2. Screen printing was performed on the entire surface of the carbon paper on which the microporous layer was formed. Thereafter, the screen-printed anode catalyst paste was dried at room temperature to produce an anode electrode having a catalyst layer with a thickness of about 50 μm. Further, in the same manner as the anode electrode, the cathode catalyst paste was screen-printed on carbon paper (SBC Carbon: 25BC) to form a cathode electrode having a catalyst layer with a thickness of about 50 μm.

Next, using the above electrolyte membrane, sandwiching the electrolyte membrane, the anode electrode and the cathode electrode overlap each other at the center of the electrolyte membrane, and the anode catalyst layer and the cathode catalyst layer are in contact with the electrolyte membrane. The film and the cathode were stacked in this order. This laminated body was placed in the through hole of a frame-shaped Teflon spacer (Teflon (registered trademark)) having a square-shaped through hole of 50 mm × 50 mm and having a thickness of 100 mm × 100 mm and a thickness of 0.30 mm. These were sandwiched between stainless plates having a size of 100 mm × 100 mm and a thickness of 3 mm, and then thermocompression bonded at 130 ° C. and 5 kgf / cm ² for 2 minutes in the thickness direction of the stainless plate to integrate the anode electrode, the electrolyte membrane, and the cathode electrode. A membrane electrode composite was prepared. The produced membrane electrode assembly was cut with a trimming knife so as to have an outer shape of 2 mm × 25 mm and an electrode portion of 2 mm × 23 mm, thereby producing a strip-shaped membrane electrode assembly.

(2) Production of Anode Current Collection Layer Anode current collection layer 905 shown in FIG. 9 was produced as follows. A through-hole 906 having a diameter of 300 μm is formed on a flat plate made of sulfuric acid-resistant stainless steel SUS316L having a width of 2 mm, a length of 25 mm, and a thickness of 300 μm by etching so as to be parallel to the long side at a pitch of 3000 μm in the long side direction. Thus, two rows of through holes extending in parallel with the long side of the flat plate were formed. A through hole 906 was formed from 3000 μm from the short side of the stainless steel flat plate. At the same time, a groove having a depth of 200 μm and a width of 800 μm was dug by etching to form a fuel flow path 1007. The distance between the end of the through hole 906 and the edge of the groove was 150 μm on each of the left and right sides.

  Next, a dry film made of a resist resin having a thickness of 45 μm is hot-laminated on the anode current collecting layer 905, exposed to light, developed using a photoresist mask, and cured at 350 ° C. to form a fuel permeable layer 910. (See FIG. 9). The fuel permeable layer 910 has a width of 950 μm with respect to the width of 800 μm of the fuel flow path 1007, and is formed so as to close the groove of the fuel flow path 1007. At this time, the fuel permeable layer 910 protruded from the groove by 75 μm on the left and right. Next, in the middle of the fuel permeable layer 910, a plurality of openings having a width of 10 μm were provided in a row in the longitudinal direction at a pitch of 600 μm (not shown).

(3) Production of unit cell From the bottom, the anode current collecting layer 905, the fuel permeable layer 910, and the membrane electrode composite (laminated so that the anode electrode side is on the fuel permeable layer 910 side) were laminated in this order. The laminated body was placed in the through hole of a frame-shaped Teflon spacer (Teflon (registered trademark)) having a square through hole of 50 mm × 50 mm and having a thickness of 100 mm × 100 mm and a thickness of 0.6 mm. These were sandwiched between 100 mm × 100 mm and 3 mm thick stainless steel plates, and then thermocompression bonded at 130 ° C. and 5 kgf / cm ² for 2 minutes in the thickness direction of the stainless steel plates to integrate the laminates to produce unit cells. A total of 10 unit cells were produced by the same method.

(4) Production of Spacer A spacer 1100 shown in FIG. 10 was produced as follows. A titanium fiber sintered body having an outer shape of 1 × 20 mm, a thickness of 600 μm, and a porosity of 80% (manufactured by Bekinit Co.) is laminated with a titanium foil having an outer shape of 1 × 20 mm and a thickness of 100 μm so that the outer shapes overlap each other. The titanium fiber sintered body and the titanium foil were joined. On the titanium foil side of the joined body, a discharge channel 1101 composed of a groove having a depth of 100 μm and a width of 500 μm is formed at the center of the joined body, and press-molded so that the total thickness of the joined body is 400 μm. A spacer 1100 was produced.

(5) Production of fuel cell unit The first fuel cell layer was produced by arranging five unit cells on a plane with the long sides of the unit cells facing each other, with a gap of 1 mm between the opposed long sides. Next, on the surface of the spacer 1100 where the discharge flow path 1101 is formed, a conductive paste (made by Tamra Kaken: CARBOLLOID MRX-713J) is applied to a portion other than the discharge flow path 1101 by screen printing. It apply | coated so that it might become a 30 micrometer thickness. The spacer 1100 is orthogonal to the unit cell of the first fuel cell layer, and a total of seven spacers 1100 are arranged at a pitch of 2 mm so that the through hole 906 of the anode current collecting layer 905 and the surface of the discharge channel 1101 of the spacer 1100 overlap. Were stacked so that the end of each spacer would protrude 6 mm in the same direction. A gas permeation preventive layer was applied to a portion where the spacer 1100 and the first fuel cell layer did not overlap by previously laminating a polyimide adhesive tape having a thickness of 50 μm. The laminate was placed in the through hole of a frame-shaped Teflon spacer (Teflon (registered trademark)) having a square-shaped through hole of 50 mm × 50 mm and a thickness of 1 mm. These were sandwiched between 100 mm × 100 mm and 3 mm thick stainless steel plates, and then thermocompression bonded at 130 ° C. and 5 kgf / cm ² in the thickness direction of the stainless steel plates for 30 minutes to integrate the laminate, and the first fuel cell layer, A unit of a fuel cell that is a laminate of spacer layers composed of seven spacers 1100 was produced. FIG. 11 is a top view schematically showing the obtained fuel cell unit. In FIG. 11, the anode current collecting layer of the unit cell constituting the first fuel cell layer can be clearly grasped so that the positional relationship between the through hole 906 of the anode current collecting layer 905 and the discharge flow path 1101 of the spacer 1100 can be clearly understood. Is shown.

(6) Production of Fuel Cell Stack A second fuel cell layer was produced using the unit cell in the same manner as the first fuel cell layer. Next, a conductive paste is formed on the spacer surface (surface opposite to the side on which the first fuel cell layer is laminated) of the fuel cell comprising the laminate of the first fuel cell layer and the spacer layer. (Tamura Kaken Co., Ltd .: CARBOLLOID MRX-713J) was applied by screen printing so that the coating thickness was 30 μm. Next, the unit cell of the first fuel cell layer and the unit cell of the second fuel cell layer are overlapped at the same position via the spacer layer of the fuel cell unit, and the unit constituting the second fuel cell layer The second fuel cell layer was laminated on the unit of the fuel cell so that the cathode of the cell and the spacer 1100 face each other. The laminate was placed in the through hole of a frame-shaped Teflon spacer (Teflon (registered trademark)) having a square through hole of 50 mm × 50 mm and having a thickness of 100 mm × 100 mm and a thickness of 1.5 mm. These were sandwiched between 100 mm × 100 mm and 3 mm thick stainless steel plates, and then thermocompression bonded at 130 ° C. and 5 kgf / cm ² for 30 minutes in the thickness direction of the stainless steel plates to integrate the laminate, and the first fuel cell layer from above Then, a laminated body in which a spacer layer composed of the spacer 1100 and a second fuel cell layer were laminated in order was produced.

  Subsequently, in the same manner as in the fuel cell unit manufacturing method, seven spacers 1100 are stacked and integrated on the anode current collecting layer of the second fuel cell layer, and two layers of the fuel cell layer and the spacer layer are formed. Fuel cell stacks that were alternately stacked were prepared. In the integration, a frame-shaped Teflon spacer (Teflon (registered trademark)) having a thickness of 1.9 mm was used.

(7) Production of Fuel Cell System A Teflon tube (Teflon (registered trademark)) having an outer diameter of 360 μmφ (inner diameter 150 μmφ) is inserted into the fuel flow channel from the end of the fuel flow channel 1007, and the tube and the end of the fuel flow channel 1007 The gap between the two was filled with an epoxy resin and dried to produce a fuel supply connection.

  Next, the protruding end of each spacer (14 in total) where the fuel cell layer is not disposed is inserted into a Tygon tube (trademark) having an inner diameter of 1.6 mmφ (outer diameter of 3.2 mmφ), and a gap is formed. The tube and the discharge flow path 1101 of the spacer 1100 were connected to each other by filling with epoxy resin and drying. The other end of the discharge channel not connected to the tube was sealed by applying an epoxy resin and drying so that the generated gas was not discharged.

  Next, the fuel cell stack is placed in an acrylic casing having an outer width of 3 cm, a depth of 3 cm, and a height of 1 cm. In order to be discharged, the tip of the tube connected to each spacer was passed through a surface without an air supply opening, and the tip of each tube was pulled out of the acrylic housing. A hollow made of acrylic having an outer shape of a rectangular parallelepiped shape as a gas collecting portion on the outer side of the surface without an air supply opening in the acrylic housing, adjacent to the surface without the opening. The member was installed. The hollow member includes an opening (gas discharge port) provided on a side surface thereof and connected to the hollow portion for discharging the aggregated generated gas, and the side surface provided with the gas discharge port. A plurality of protrusion-like connectors are provided on the side surface opposite to. The tip of each tube was connected to the connector so that the inside of each tube communicated with the cavity of the gas collecting portion.

Using a pump, a 3M methanol aqueous solution was supplied from the Teflon tube (Teflon (registered trademark)) at a rate of 0.5 cc / min to evaluate the power generation. After 5 minutes, the output density was 40 mW / cm ^2. Obtained. The power density after 10 minutes was similarly 40 mW / cm ² .

<Comparative Example 1>
A fuel cell in the same manner as in Example 1 except that the tube for discharging the generated gas to the outside of the acrylic casing and the gas collecting portion were not provided and the end of the discharge flow path of the spacer was not sealed. A stack was made. At this time, since both ends of the discharge channel are in the acrylic casing, the generated gas from the discharge channel is discharged into the acrylic casing.

When power generation was evaluated under the same conditions as in Example 1, an output density of 35 mW / cm ² was obtained after 5 minutes. The power density after 10 minutes decreased to 23 mW / cm ² . Although the fuel cell stack of Example 1 does not have the gas concentration part according to the present invention, it is easy to obtain the same effect as the fuel cell stack of Example 1 even when the gas concentration part is provided. Therefore, it is understood that the power generation characteristics of the fuel cell system of the present invention are superior in terms of both maximum power density and stability, compared with the comparison between Example 1 and Comparative Example 1.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  100, 701a Fuel cell system, 101, 201, 701b Fuel cell stack, 102, 802 Gas concentrator, 103, 303, 803 Unit cell, 104 Opening, 105, 605, 705 Generated gas guiding path, 106, 606, 706 Gas outlet 107, 507, 807, 907, 1100 Spacer, 110, 310 First fuel cell layer, 115 First spacer layer, 120, 320 Second fuel cell layer, 125 Second spacer layer, 130 , 140, 330 gap, 150 gas permeation prevention layer, 202, 402 electrolyte membrane, 203, 403 anode electrode, 204, 404 cathode electrode, 205, 405, 905 anode current collecting layer, 206, 906 through-hole, 207, 407, 907, 1101 discharge flow path, 208, 408, 1007 fuel Road, 209,409 gas-liquid separation layer, 210,410,910 fuel permeation layer, 600, 700 electronic device, 601, 701 fuel cell system or a fuel cell stack, 602 display.

Claims (18)

A fuel cell stack and a gas concentrator,
A fuel cell system in which an anode electrode of the unit cell included in the fuel cell stack and the gas collecting part are communicated with each other through a generated gas discharge channel provided in the fuel cell stack. A fuel cell stack including one or more fuel cell layers in which two or more unit cells each having a cathode electrode, an electrolyte membrane, an anode electrode, and an anode current collecting layer in this order are arranged on the same plane;
A hollow body having a hollow portion therein, and a gas collecting portion including an opening communicating with the hollow portion,
The hollow portion of the gas aggregation portion and the anode electrodes of all unit cells of at least one fuel cell layer among the fuel cell layers are formed by a generated gas discharge flow path provided in the fuel cell stack. The fuel cell system according to claim 1, which is in communication. In the fuel cell stack, a fuel cell layer in which two or more unit cells are arranged on the same plane and a spacer layer composed of one or more spacers are in contact with an anode current collecting layer of the unit cell. Including one or more fuel cells,
The hollow portion of the gas concentrating portion and the anode electrodes of all unit cells of the at least one fuel cell layer are communicated with each other by a generated gas discharge channel provided in the fuel cell. Item 3. The fuel cell system according to Item 2. The gas concentrating portion is connected to end portions of all the spacers included in at least one spacer layer,
The product gas discharge flow path is
A through hole penetrating the anode current collecting layer of the unit cell in the thickness direction;
A flow path formed in the spacer, which communicates with the through-hole and extends to the end connected to the gas collecting portion;
The fuel cell system according to claim 3, comprising: The gas concentrating portion is connected to end portions of all unit cells included in at least one fuel cell layer,
The generated gas discharge channel is formed of a channel formed in the anode current collecting layer so as to be in contact with the anode electrode of the unit cell and extending to the end connected to the gas collecting unit. Item 4. The fuel cell system according to Item 2 or 3. The fuel cell stack is formed by stacking two or more fuel cells,
The gas concentrating portion is connected to the end portions of all the spacers included in the fuel cell stack or the end portions of all unit cells included in the fuel cell stack,
The hollow portion of the gas collecting portion and the anode electrodes of all unit cells of the fuel cell stack are communicated with each other by a product gas discharge flow path provided inside each fuel cell. 5. A fuel cell system in any one of 5.   The fuel cell system according to any one of claims 2 to 6, wherein the fuel cell layer is formed by arranging two or more unit cells with a gap on the same plane. Comprising one or more gas concentrators,
The fuel cell system according to any one of claims 2 to 7, wherein all of the gas concentrating portions are disposed adjacent to one side surface of the fuel cell stack.   The fuel cell system according to any one of claims 2 to 8, wherein the gas collecting part includes a hollow product gas guide path connected to the opening.   10. The fuel cell system according to claim 9, wherein a harmful component removal filter is provided in an opening opposite to the opening in the product gas guiding path.   The fuel cell system according to claim 9 or 10, wherein an inner wall surface of the generated gas guide path is subjected to water repellent treatment. The spacer layer is formed by arranging two or more spacers with a gap on the same plane,
The fuel cell system according to any one of claims 3 to 11, wherein in the fuel cell, two or more unit cells included in the fuel cell layer and two or more spacers included in the spacer layer are arranged so as to intersect each other.   An electronic device comprising the fuel cell system according to claim 1. A fuel cell system according to any one of claims 9 to 11, comprising:
The generated gas guide path is an electronic device made of any one of the constituent members constituting an electronic device having a hollow portion formed therein.   The electronic device according to claim 14, wherein an opening on the side opposite to the opening in the generated gas guiding path is disposed at an outer edge of the electronic device.   The electronic device according to claim 14, wherein an opening opposite to the opening in the product gas guiding path is disposed on the back side of the electronic device. In the electronic device, the fuel cell system is disposed at a position where air can be supplied from the outside of the electronic device to at least a part of the outer surface of the fuel cell stack,
The electronic device according to any one of claims 13 to 16, wherein the gas collecting unit is disposed adjacent to an outer surface different from the outer surface of the fuel cell stack to which air is supplied from the outside of the electronic device. A battery storage chamber for storing the fuel cell system or the fuel cell stack;
The electronic device according to claim 17, wherein the battery housing chamber has an opening that communicates the inside of the battery housing chamber with the outside of the electronic device.

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