JP2004319430A - Direct type fuel cell generator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a direct methanol fuel cell generator composed of a plurality of electromotive parts with little output deviation for each electromotive part to which fuel can be stably supplied. <P>SOLUTION: The fuel cell generator comprises at least two electromotive units provided with an anode electrode including an anode catalyst layer, a cathode electrode including a cathode catalyst layer, and an electrolyte film interposed between the anode electrode and the cathode electrode; a fuel container containing fuel; and a fuel flow passage for supplying the fuel to the electromotive units. The fuel flow passage 103 is constructed so that the fuel flows out from the fuel container, flows through the first electromotive unit 108a and the second electromotive unit 108b, and flows back to the first electromotive unit 108a, without branching. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a direct fuel cell power generation device using methanol or an aqueous methanol solution as a fuel, and more particularly to a device capable of obtaining a stable output by improving the shape of a flow path of a flow path plate through which fuel flows.

  A fuel cell is a device that converts chemical energy of a fuel such as hydrogen, hydrocarbon, or alcohol into electric energy by an electrochemical reaction, and is expected to be a high-efficiency and low-pollution power generation device.

  Among these fuel cells, a polymer electrolyte fuel cell using an ion exchange resin membrane as an electrolyte is a fuel cell whose development has been accelerated in recent years as a power supply for electric vehicles and a power supply for houses. This polymer electrolyte fuel cell supplies a fuel gas containing hydrogen to the anode electrode side and oxygen gas or air to the cathode electrode side. At the anode electrode and the cathode electrode, reactions shown in (Formula I) and (Formula II) are caused, respectively, to generate electromotive force.

Anode electrode: 2H2 → 4H ++ 4e− (formula I)
Cathode electrode: O2 + 4H ++ 4e- → 2H2O (formula II)
That is, electrons and protons are generated from hydrogen by the catalyst inside the anode electrode, and the electrons are extracted to an external circuit. When the protons travel through the proton conductive electrolyte membrane and reach the cathode electrode, they react with electrons and oxygen on the catalyst inside the cathode electrode to generate water. Electric power is generated by such an electrochemical reaction.

  On the other hand, direct methanol fuel cells have recently attracted attention. FIG. 59 shows the structure of each electromotive unit in the direct methanol fuel cell. The direct methanol fuel cell has a configuration in which a proton conductive electrolyte membrane 7 (for example, a perfluorocarbon sulfonic acid-based ion exchange membrane, preferably Nafion manufactured by DuPont) is used for the anode electrode 3 and the cathode electrode 6. It has been pinched. Each electrode is composed of substrates 1 and 5 and catalyst layers 2 and 4. The catalyst layer is composed of a perfluorocarbon sulfonic acid resin in which a catalyst or a carbon black carrying a catalyst is dispersed. The catalyst is generally a noble metal catalyst or an alloy thereof, and is often used by being supported on a carrier such as carbon black. A Pt-Ru alloy is preferably used as a catalyst for the anode electrode, and Pt is preferably used as a catalyst for the cathode electrode. In order to drive this fuel cell, methanol and water are supplied to the anode electrode side, and oxygen gas or air is supplied to the cathode electrode, so that the reactions shown in (formula III) and (formula IV) occur at the anode electrode and the cathode electrode, respectively. Occurs.

Anode electrode: CH3OH + H2O → CO2 + 6H ++ 6e-
... (Formula III)
Cathode electrode: (3/2) O2 + 6H ++ 6e- → 3H2O
... (Formula IV)
That is, the catalyst in the anode electrode catalyst layer generates electrons, protons, and carbon dioxide from methanol and water, and the generated carbon dioxide is released into the atmosphere. Electrons are taken out as an electric current. In addition, protons move through the proton conductive electrolyte membrane and reach the cathode electrode, where they react with electrons and oxygen to produce water. Electric power is generated based on this electrochemical reaction.

  In this direct methanol fuel cell power generator, the open circuit voltage is usually 0.6 V to 0.8 V, and in actual power generation with a load current, the voltage drops to around 0.5 V. Therefore, in order to obtain a voltage at which the operation of the electronic circuit or the electric device is compensated, it is necessary to electrically connect a plurality of electromotive unit units. Therefore, a plurality of these electromotive unit units are stacked (stacked), and a flow path shape and a pipe for uniformly supplying fuel to them are required, and various proposals have been made. The structure of many of these flow paths or pipes can be roughly classified into parallel flow paths in which the pipes and flow paths led from the fuel container containing the fuel are branched by the number of units of the electromotive unit. One flow path can be divided into two series-type flow paths in which a plurality of electromotive unit units are sequentially routed.

  However, in the former, variations in the fuel supply state for each electromotive section unit due to branching of the flow path and piping are likely to occur, and further measures are required to reduce the variations. Also in the latter case, the fuel is consumed in units of a plurality of electromotive units sequentially, so that the output due to the difference in fuel concentration between the electromotive unit located in the first half of the flow path and the electromotive unit located in the second half of the flow path Differences occur, and this requires a careful design of the channel shape to reduce the differences.

  As a method of stacking a plurality of electromotive unit units and a flow path plate, a bipolar structure in which anode electrodes or cathode electrodes of the electromotive unit units are alternately stacked so as to be aligned in one direction is widely adopted. In this bipolar structure, a flow path plate separating the electromotive section unit is formed of a member of an electric conductor, a fuel flow path is provided on one side of one flow path plate to supply fuel, and the other side is provided with an oxidizing agent. An electrical series state can be easily obtained simply by providing a flow path and supplying an oxidizing agent and simply stacking the flow path plates alternately in units of electromotive units. That is, electric wiring for serializing electric outputs from a plurality of electromotive units can be omitted, so that the stack structure can be simplified.

  However, in practice, in many cases, a means of arranging a plurality of stack units of the number of stacks in which the mechanical strength or the spatial constraint is compensated for in parallel and electrically connecting each of them is adopted. For example, a structure has been proposed in which conductive channel plates are insulated from each other by an insulating member and assembled.

In order to reduce the size of the bipolar stack, it is most effective to reduce the thickness of the flow path plate itself, excluding elements that depend on the electromotive unit itself, and a study is made from a structural and material viewpoint. ing.

  In order to structurally reduce the thickness of the flow channel plate, a method of reducing the depth of the anode and cathode flow channels and a method of reducing the thickness of the layer separating the anode / cathode flow channel are considered. Regarding the former, it is limited by the pressure loss in the flow path, and it is theoretically possible to make it very thin as long as the load on the pump is ignored, but in practice it includes the power consumed by the pump The power generation efficiency and work accuracy of the entire system must be considered. In the latter case, the permeability of the material to fuel and oxidant is limited, and the strength of the material is limited as the film becomes thinner.

  Attempts have also been made to reduce the thickness of the flow channel plate from a material viewpoint. Normally, carbon is often used as a material having electrical conductivity as a flow path plate material. However, in the case of pure carbon, from the viewpoint of strength, permeability, and machining accuracy, it is not preferable to set the thickness to 1 to 2 mm or less. Impossible. Therefore, a resin having the above characteristics improved by infiltrating or mixing some resin is used. However, when the proportion of non-conductive components other than carbon is increased, not only the electrical resistance is increased, but also a property comparable to the strength of a resin or plastic suitable for thin molding is generally provided. Difficult.

  In view of this, it has been proposed to use a metal as the flow channel plate in order to solve the problems of strength and permeability in the above-described carbon flow channel plate. However, the channel plate is in contact with the fuel, the oxidizing agent, and the electrode portion, and is a portion for taking out an electric current. Therefore, the metal used as the channel plate material must have sufficient corrosion resistance. Metals available from a chemical point of view are noble metals such as gold, platinum, rhodium, iridium and ruthenium, but it is unlikely that a flow path plate using these metal materials will be industrially applied in terms of cost. . Therefore, when forming a metal channel plate, usually, a method is used in which a base material such as titanium or some alloys, which is a base metal having slightly corrosion resistance, is used as a base material, and the entire surface is coated with the above-mentioned noble metal-based metal. . However, even in the thus prepared flow path plate, if a pinhole-like flaw occurs when the electrode is tightened, it is considered that corrosion proceeds from that part. It is considered that using carbon is advantageous at present.

  As described above, various attempts have been made to reduce the thickness of the bipolar stack from the viewpoints of structure and material, but have not been able to significantly improve the current situation. In such a situation, as one method of structurally reducing the thickness of the stack, only one oxidant or fuel is supplied to one channel plate, and only the cathode electrode or the anode electrode is provided on both surfaces of the channel plate. In recent years, a monopolar stack structure has also been proposed.

  In the monopolar structure, compared to the bipolar structure, since the directions of both poles of the electromotive section unit are not aligned in the stack lamination direction, it is not possible to easily form an electrical series state by a plurality of electromotive section units simply by laminating. There are drawbacks. On the other hand, since only one of the oxidant and the fuel is supplied to one flow path plate, there is no need to make the front and rear flow paths independent, and therefore the thickness that separates the front and rear flow paths is eliminated. This is structurally advantageous in that it can be performed. Further, even in a flow path having the same depth as that of the bipolar structure, it is expected that the pressure loss of the flow path is reduced because the wetting edge length is shortened, so that the flow path depth can be further reduced.

  Therefore, a monopolar stack structure is promising as a stack structure of a fuel cell power generator for a portable information terminal, which is particularly demanded for miniaturization. Furthermore, considering such applications, there is a high possibility that a direct methanol fuel cell that does not require auxiliary equipment such as a vaporizer or a reformer will be used, and a monopolar stack structure for direct methanol fuel cells will be proposed. Is waiting.

  Here, in the direct methanol fuel cell, as the methanol aqueous solution is consumed at the anode electrode, carbon dioxide as a reaction product is generated as bubbles at the same anode electrode. In addition, the volume of the gaseous carbon dioxide generated is several times the volume of the supplied aqueous methanol solution, and the volume expansion of the carbon dioxide in the flow channel is caused by the volume expansion of the aqueous methanol solution in the flow channel. This is a major obstacle to the flow. Once the flow of the aqueous methanol solution in the flow channel is hindered, fuel supply is limited at the anode electrode, and it becomes impossible to reduce the high load current density.

  That is, this means a decrease in the output of the direct methanol fuel cell, and the output is not restored until the carbon dioxide remaining inside the flow path is swept. Although the problem of the gas-liquid two-layer flow can occur in the flow path on the cathode electrode side, the volume change rate of the liquid is smaller than that of gas, and the frictional force between the walls is large. This is much more serious than the problem that occurs inside the flow path on the cathode electrode side. That is, in a direct methanol fuel cell that supplies gaseous hydrogen as a fuel to the anode electrode and supplies a liquid fuel rather than a polymer electrolyte fuel cell (PEM, PEFC) that does not generate gaseous products. This is a serious problem, and designing a flow channel from this viewpoint is an important point in proposing a monopolar flow channel plate for direct methanol fuel cells.

  Therefore, first, in order to realize a smooth flow of the aqueous methanol solution inside the flow channel in the direct methanol fuel cell, it is generally practiced to reduce the cross section of the flow channel. This is because carbon dioxide generated inside the flow passage is easily pushed out by effectively increasing the flow velocity of the fuel flowing through the flow passage. Furthermore, in order to allow the fuel to reach the entire surface of the unit of the electromotive section with the flow path cross section reduced, the serpentine flow path, which has a shape in which a narrow flow path is folded many times, is a direct methanol fuel. Often used as a battery flow path.

  In particular, since the serpentine flow path can be easily formed as a bipolar flow path plate, a serpentine flow path is often used when forming a bipolar flow path plate. Further, in order to increase the power generation efficiency, the width of the comb-shaped convex portion that reverses and separates the adjacent flow paths is narrowed so as to increase the area where the electromotive unit unit and the aqueous methanol solution are in contact.

  However, if the width of the comb-like projections is extremely narrowed to increase the power generation efficiency, the outermost current collector of the electrode in the unit of the electromotive section is porous, and bubbles of carbon dioxide expanding therefrom are generated. A short circuit occurs in the adjacent flow path, and pressure is not applied in an orderly manner in the flow direction of the flow path. As a result, a problem arises in that fuel is accumulated in the flow path portion where the carbon dioxide gas bubbles cannot pass through due to the short circuit. Conversely, if a fuel short circuit occurs, the problem of carbon dioxide retention will occur. Therefore, in general, the width of the comb-shaped convex structure is often designed on the basis of about 1 mm.

  That is, in order to appropriately supply fuel to the bipolar flow channel plate in the direct methanol fuel cell, it is desirable to employ a serpentine flow channel having a comb-shaped convex structure having a width of about 1 mm. It is necessary to press the electrode surface of each electromotive section against the flow channel plate by pressure.

  However, a similar channel structure cannot be used for a monopolar channel plate. This is because, in a serpentine type channel formed so as to penetrate both surfaces of the channel plate, the comb-like convex structure is floating only at a very small portion from the periphery of the channel plate, and the bipolar plate This is because carbon dioxide and fuel can easily be short-circuited even at a pressure in the flow path that does not cause much problem in the mold flow path plate. In addition, a method for solving this problem has not yet been proposed, and the flow path shape of a monopolar flow path plate that has been studied in recent years has only a plurality of straight flow paths arranged in parallel. It simply uses a simple structure. Therefore, proposals for a flow path shape for improving power generation efficiency, a flow path plate structure for realizing the shape, and a material are awaited.

The problem of the monopolar structure as described above is the same also in the case of a metal channel plate that is easy to form, and because the number of cut surfaces of the channel plate becomes extremely large, the uniformity of the corrosion resistance treatment is reduced. It becomes even more difficult to raise. Further, similarly to the bipolar structure, when arranging the electromotive section units in parallel in the plane direction of the flow path plate, it is necessary to take a complicated structure via an insulating member.
JP-A-11-67258

  The direct methanol fuel cell described above has the following problems. In other words, direct methanol fuel cells are expected to be used as power sources for portable electronic devices due to the high energy density of methanol, which is a liquid fuel, and it is necessary to pressurize the fuel because the fuel is liquid. And the possibility of fuel leakage from the gap between the flow path and the unit of the electromotive unit is smaller than that of the polymer electrolyte fuel cell using hydrogen as fuel. Therefore, unlike the fuel supply flow path of the polymer electrolyte fuel cell, it is thought that a relatively complicated flow path structure and flow path arrangement are possible. No proposal has been made for a flow path structure in a direct methanol fuel cell power generator that solves the above points.

  Furthermore, as long as a flow channel plate mainly composed of carbon for current collection is adopted, the need to improve and develop carbon materials to reduce the thickness of each flow channel plate, parallelization in the plane direction The need for integrated molding technology using insulating members for manufacturing, and the complexity of multiple types of members required in the manufacturing process, etc., has led to the rapid development and production of small fuel cell power generators for portable devices. It is an obstacle.

  Accordingly, the present invention provides a direct methanol fuel cell power generation system comprising a plurality of electromotive unit units, wherein the output bias for each electromotive unit unit is reduced, and a direct fuel cell power generation system capable of performing stable fuel supply is provided. It is intended to provide a device.

  In order to solve the above problems and achieve the object, a direct fuel cell power generator according to the present invention is configured as follows.

(1) An electromotive unit unit group including a plurality of electromotive unit units formed by sandwiching an electrolyte membrane between an anode electrode including an anode catalyst layer and a cathode electrode including a cathode catalyst layer; A first flow path plate which is disposed in contact with the anode electrode and in which a first flow path through which fuel flows is formed, and which is disposed in contact with the cathode electrode of the electromotive unit unit group. A second flow path plate formed with a second flow path through which an oxidant flows. The first flow path does not branch from an inlet to an outlet of the first flow path. It is formed so as to pass so as to contact all anode electrodes of the unit group and to contact the anode electrode of at least one electromotive unit a plurality of times.

(2) an electromotive unit unit group including a plurality of electromotive unit units formed by sandwiching an electrolyte membrane between an anode electrode including an anode catalyst layer and a cathode electrode including a cathode catalyst layer; A first flow path plate, which is disposed in contact with the cathode electrode and in which a first flow path through which the oxidant flows is formed, and is disposed in contact with the anode electrode of the electromotive unit unit group; And a second flow path plate in which a second flow path through which fuel flows is formed, wherein the first flow path is formed without branching from an inlet to an outlet thereof. It is characterized in that it is formed so as to pass so as to contact all the cathode electrodes of the unit unit group and to contact the cathode electrode of at least one electromotive unit unit a plurality of times.

(3) The direct fuel cell power generator according to (1) or (2), wherein n is the number of electromotive unit units included in the electromotive unit unit group, and s is the first flow path. Is the number of times each passes through each electromotive unit unit, h is the number of flow path regions and the product of n and s, and br, m (1 ≦ m ≦ n, 1 ≦ r ≦ s) When the assigned number is a natural number less than or equal to h, Zbr, m is the distance from the flow path supply port of each flow path area, and L0 indicates the effective length of the first flow path.

  Is satisfied.

(4) First and second electromotive section unit groups formed by sandwiching an electrolyte membrane between an anode electrode including an anode catalyst layer and a cathode electrode including a cathode catalyst layer, and a first electromotive section unit group A first flow path plate, which is disposed in contact with the anode electrode and has a first flow path through which fuel flows, and a cathode electrode of the first electromotive unit unit group on one surface side; A second flow path through which the oxidant flows is formed, and a third flow path through which the oxidant flows in contact with the cathode of the second electromotive unit unit group on the other surface side. Formed in the second flow path plate and the third flow path disposed in contact with the anode electrode of the second electromotive unit unit group and formed with the fourth flow path through which fuel flows. A road plate, and an external electrode provided for connection with the outside, the first to third flow path plates are formed of an insulating member, and the first to third flow plates are provided. The road plate, wherein the conductive portion to conduct the anode and a cathode each other or between the external electrodes of the first and second electromotive portion unit layer is formed.

(5) First and second electromotive unit units formed by sandwiching an electrolyte membrane between an anode electrode including an anode catalyst layer and a cathode electrode including a cathode catalyst layer, and a first electromotive unit unit group A first flow path plate provided in contact with the cathode electrode and having a first flow path through which the oxidant flows, and an anode electrode of the first electromotive unit unit group on one surface side And a second flow path through which fuel flows in contact with the anode of the second electromotive unit unit group is formed on the other surface side. The formed second flow path plate and the third flow path which is disposed in contact with the cathode electrode of the second electromotive unit unit group and has a fourth flow path through which the oxidant flows. A road plate, and an external electrode provided for connection with the outside, the first to third flow path plates are formed of an insulating member, and the first to third flow plates are provided. The road plate, wherein the conductive portion to conduct the anode and a cathode each other or between the external electrodes of the first and second electromotive portion unit layer is formed.

(6) In the direct fuel cell power generator described in the above (4) or (5), in the second flow path plate, the flow path bends or meanders in a plane direction of the flow path plate. The second flow path plate is formed in a shape, penetrates in the thickness direction of the second flow path plate, and one flow path is formed by the second flow path and the third flow path.

(7) In the direct fuel cell power generator according to the above (6), in the second flow path plate, a reinforcing member for maintaining a cross-sectional shape of each flow path is formed in the flow path. It is characterized by having.

(8) In the direct fuel cell power generator according to (7), the reinforcing member has a cross-sectional area of 50% or less of a cross-sectional area of the flow path and a thickness of 0.2 mm or more. It is characterized by having.

(9) In the direct fuel cell power generator according to the above (7) or (8), the reinforcing member forms a part of the conductive portion.

(10) In the direct fuel cell power generator according to the above (4) or (5), the flow path plate is configured such that partial portions of the flow path that are in contact with the anode electrode or the cathode electrode are formed. In between, there is a through portion formed in a tunnel shape, and an outlet or an entrance of the through portion is 0.5 mm or more from the end of the anode electrode or the cathode electrode to the inside of the anode electrode or the cathode electrode. It is characterized by being arranged within a range of 0 mm or less.

(11) In the direct fuel cell power generator according to the above (4) or (5), the flow path plate may include a part of the flow path that is in contact with the anode electrode or the cathode electrode. Having a through-hole formed in a tunnel shape between a supply port and a discharge port of the flow path, and an outlet or an inlet of the through-hole is provided from an end of the anode electrode or the cathode electrode to the anode electrode. Alternatively, they are arranged in a range of 0.5 mm or more and 1.0 mm or less inside the cathode electrode.

(12) The direct fuel cell power generator according to the above (4) or (5), wherein the flow path plate is formed by bonding a plurality of insulating resin members. I do.

(13) The direct fuel cell power generator according to the above (4) or (5), wherein the insulating member is a polyetherimide resin, a polyimide resin, a polyamideimide resin, a polysulfone resin, a polyethersulfone resin, Melamine phenol resin, silicone resin, polycarbonate resin, heat-resistant vinyl ester resin, bisphenol F type epoxy resin, phenol novolak type epoxy resin, phenol resin, diallyl phthalate resin, polyamide resin, polybutylene terephthalate resin, or different It is characterized by being formed by a combination of a plurality of resin members.

(14) In the direct fuel cell power generator according to the above (4) or (5), a space for temporarily storing the fuel or the oxidant is integrally formed in the flow path plate. It is characterized by having.

(15) At least two electromotive unit units each including an anode electrode including an anode catalyst layer, a cathode electrode including a cathode catalyst layer, and an electrolyte membrane disposed between the anode electrode and the cathode electrode. A fuel container containing fuel, and a flow path plate provided with a flow path for supplying an oxidizing agent or fuel to the unit of the electromotive section. And a flow channel that returns to the first electromotive unit unit again via the electromotive unit unit and the second electromotive unit unit, and does not branch between them. It is characterized by the following.

(16) The direct fuel cell power generator according to any one of (1) to (15), wherein n is the number of electromotive unit units included in the electromotive unit unit group, and I is for each electromotive unit unit. , C _MeOH is the concentration (mol / l) of the supplied methanol aqueous solution fuel, and Y is the total amount (l / min) of the methanol aqueous fuel supplied to the electromotive unit unit group. When the temperature of each electromotive unit is in the range of 40 ° C to 70 ° C,
Y ≦ Y ₀ × 2 (101)
Y ₀ = 1.04 × 10 ⁻⁴ × nI / C _MeOH (102)
1.0 ≦ C _MeOH ≦ 5.0 (103)
The direct-type liquid fuel cell power generator according to any one of claims 1 to 15, wherein:

(17) The direct fuel cell power generator according to any one of (1) to (16), wherein a liquid fuel is supplied to supply liquid fuel to the flow path plate that is in contact with the anode electrode of the electromotive unit unit group. A device, an oxidant supply device for supplying an oxidant to the flow path plate contacting the cathode electrode of the electromotive unit unit group, and a liquid fuel containing liquid fuel and supplying the liquid fuel to the liquid fuel supply device A container, a gas-liquid separation mechanism that separates only a gas component from the exhaust from the anode electrode, and a part of the power output obtained from the electromotive unit unit group, the liquid fuel supply device and the oxidant supply device. And an electric circuit for supplying at least a part of the remaining power output to an external electric device.

  ADVANTAGE OF THE INVENTION According to this invention, in the direct methanol fuel cell power generation device composed of a plurality of electromotive unit units, it is possible to reduce the bias of output for each electromotive unit unit and to perform stable fuel supply. .

[First Embodiment]
FIG. 1 is a perspective view showing a direct-type methanol fuel cell power generation apparatus 100 according to a first embodiment of the present invention, and FIGS. 2 (a) to 2 (d) show direct-type methanol fuel cell power generation. 3A and 3B are diagrams illustrating a main part of the device 100, wherein FIG. 4A is a top view of an insulating flow path plate 101 located on the upper side in the figure, and FIG. FIG. 1C is a cross-sectional view of the direct methanol fuel cell power generator 100 taken along the line α1-α1 in FIGS. 1A and 1B and viewed in the direction of the arrow, and FIG. It is sectional drawing which cut | disconnected the electric power generation apparatus 100 by (alpha) 2- (alpha) 2 line in (a), (b), and was seen in the arrow direction.

  2, reference numeral 101 denotes an insulating flow path plate (fuel side), 102 denotes an insulating flow path plate (oxidant side), 103 denotes a fuel flow path, 104 denotes a fuel flow path supply port, 105 denotes a fuel flow path discharge port, 106 is a flow path cover on the back of the flow path, 107 is a resin sealing material, 108a and 108b are units of an electromotive unit, 109 is an air channel, and 110 is a channel so as not to face the units 108a and 108b. A flow channel portion 111 bent toward the flow channel cover 106 indicates a metal thin film for extracting current. The electromotive section units 108a and 108b employ the structure shown in FIG. 58 described above. In FIG. 2, reference numerals 103a to 103h indicate individual regions in the fuel flow channel 103.

  The fuel passage supply port 104 of the main part of the power generation unit is connected to fuel supply means via a fuel pump (not shown) so that fuel is supplied. Further, an air pump (not shown) for supplying an oxidizing agent such as air is connected to the air flow path 109, and an electrode terminal (not shown) is also connected to the metal thin film 111 for extracting current. Are connected to form a fuel cell power generator. The shape of the air flow path 109 for supplying air is the same as that of the conventional parallel flow path (see FIG. 15).

  In the direct methanol fuel cell power generator configured as described above, power is generated as follows. That is, the fuel such as the aqueous methanol solution supplied from the fuel supply means is supplied from the fuel channel supply port 104. Subsequently, the fuel sequentially passes through the fuel passage 103 facing the unit 108a through the regions 103a, 103b, and 103c, and further passes through the fuel passage 103 facing the unit 108b with the regions 103d, 103e, and 103f. , 103g in this order, and further discharged from the fuel passage outlet 105 through the region 103h facing the unit 108a. As described above, while the fuel passes through the regions 103a, 103b, 103c, and 103h, the fuel is supplied to the anode electrode substrate of the electromotive unit 108a, and while the fuel passes through the regions 103d, 103e, 103f, and 103g, the electromotive unit is supplied. Fuel will be supplied to the unit 108b.

  In such a direct methanol fuel cell power generation apparatus according to the present embodiment, the fuel flow path 103 that supplies fuel to the first electromotive section unit 108a and the second electromotive section unit 108b has a fuel flow path. The fuel flow path 103 that has passed from the first electromotive section unit 108a to the second electromotive section unit 108b without forming a branch of 103 is configured to supply fuel to the first electromotive section unit 108a again. Circulate. Then, by adjusting the contact area between the fuel flow path 103 and the power generation elements of the electromotive unit units 108a and 108b so that the fuel supply amounts are substantially equal in the plurality of electromotive unit units 108a and 108b, the power generation output can be reduced. Stability can be improved.

  FIG. 3A is a bottom view of a flow path plate 131 according to a first modified example of the flow path plate 101 described above. In FIG. 3A, 131 is a flow path plate, 132 is a portion where the electrode unit of the electromotive unit 108 is disposed, 133 and 134 are supply or discharge ports of the fuel flow path 135, and 135 is a fuel flow path. It is. In these flow path shapes, after supplying fuel to the first electromotive section unit electrode section, supplying fuel to the other electromotive section unit electrode sections, and further thereafter, the fuel flow path The supply is performed again to the first or other electromotive unit without branching. Also in this modification, the same effects as those of the direct methanol fuel cell power generator 100 described above can be obtained.

  FIG. 3B is a bottom view of a flow path plate 141 according to a second modified example of the flow path plate 101 described above. In FIG. 3B, 141 is a flow path plate, 142 is a portion where the electrode unit of the electromotive unit 108 is arranged, 143 and 144 are supply or discharge ports of the fuel flow path 145, and 145 is a fuel flow path. It is. In these flow path shapes, after supplying fuel to the first electromotive section unit electrode section, supplying fuel to the other electromotive section unit electrode sections, and further thereafter, the fuel flow path The supply is performed again to the first or other electromotive unit without branching. Also in this modification, the same effects as those of the direct methanol fuel cell power generator 100 described above can be obtained.

In the first embodiment, since the amount of fuel supplied to each unit of the electromotive unit is equivalent to the current density of each unit of the electromotive unit, the fuel supply amount should be described as Equation (3) according to the law of conservation of weight. Can be.

Here, in the formula (3), Z is the distance (cm) from the flow channel supply port of the fuel flow channel, S is the area (cm2) of the unit of the electromotive section, L0 is the effective total length of the fuel flow channel (cm), S0 is the cross-sectional area of the flow channel (cm2), J is the current density (A / cm2), ρ is the fuel density at the position Z (g / cm3), ρ0 is the initial fuel density (g / cm3), and u is the fuel flow. The fuel flow rate (cm / sec) in the passage, F is a Faraday constant of 96487 C / mol, the molecular weight of methanol was 32, the molecular weight of water was 18, and the number of electrons obtained per reaction was 6. The solution of equation (3) is given by equation (4).

The fuel concentration in equation (4) is linked to the molar concentration C (mol / l) of the methanol aqueous solution fuel by equation (5) described later, and finally equation (6) is derived. However, the density of undiluted methanol was 0.8 g / cm3.

  FIG. 4 is a characteristic diagram showing the dependence of current-voltage characteristics on the initial concentration of an aqueous methanol solution for each electromotive unit of a direct methanol fuel cell. The conditions at the time of measurement were a temperature of 70 ° C., a flow rate of the aqueous methanol fuel of 0.07 cm / min, and a flow rate of the supplied air of 11 cm / min. The electrical unit was used. From the fuel concentration dependence of the current-voltage characteristics shown in FIG. 4, when the difference in fuel concentration is within 10%, the difference in voltage value at a load current value of 50 ± 10% of the limit load current density is ignored. However, it can be understood that the change in the distance from the flow path supply port is equal to the change ΔC = C0−C in the fuel concentration by the equation (6). It is considered that even if the flow path length differs by 10%, the difference in the voltage value at a load current value of 50 ± 10% of the limit load current density can be ignored.

  In addition, in order to drive the fuel cell power generator for a long time with as little fuel as possible, it is necessary to improve the ratio of the amount of power generated to the external circuit among the amount of electricity of the supplied fuel, that is, the fuel utilization efficiency. . However, as can be seen from equation (6), the decrease in the fuel concentration in the fuel flow path is proportional to the distance from the flow path supply port, and if the fuel utilization efficiency from the fuel supply port to the discharge port increases, Indeed, it is clear that the output in the unit of the electromotive section located in the latter half of the fuel flow path is significantly reduced. That is, this is because a remarkable decrease in the fuel concentration (10% or more) in the latter half of the fuel flow path leads to a decrease in the critical load current density. Therefore, it is necessary to devise a method of reducing the difference in the concentration of the fuel supplied to all the electromotive unit units. If a method of allocating the fuel passage to the electrode unit described later is used, the fuel is supplied to each electromotive unit unit. It is possible to make the average of the fuel concentrations close to each other between the electromotive units.

  FIGS. 5A and 5B are explanatory diagrams that schematically show the fuel flow channel assignment method defined in Expression (2). FIG. 5C will be described later. 5A and 5B, reference numeral 151 denotes an electromotive unit unit, 152 denotes a divided effective channel region, 153 denotes an ineffective channel region, and 154 denotes a divided electromotive unit unit. The area 155 is a fuel supply port of the fuel flow path, and 156 is a fuel discharge port of the fuel flow path. FIG. 5A shows the correspondence between the divided effective fuel flow paths of br and m, and FIG. 5B shows the divided effective flow of Lbr and m. The correspondence relation to the road area is shown.

  5 (a) and 5 (b), the flow path width is the same at any place, n is the number of electromotive unit units that supply the fuel to the flow path, and m is an arbitrary number of the units. Of the electromotive unit. s represents the number of times the fuel flow path passes through each unit of the electromotive unit, and takes the same value for all units of the electromotive unit. That is, the fuel flow path is divided into s regions for each electromotive unit, and is divided into ns (= h) regions as a whole. Here, when the fuel is supplied to the fuel flow path, all the ns electrode regions in the figure are anode electrodes. When an air flow path is used instead of the fuel flow path, air (oxidizing agent) is supplied, and in this case, all of the ns electrode sections become cathode electrodes.

  The sequence br, m is a natural number not less than 1 and not more than h, and indicates a number assigned as shown in FIG. 5A to the h divided area. In FIG. 5A, the fuel flow path passes through the first area b1, 1 and then passes through the second area b1 and b2, and further passes through the third area b1 and b3. Repeat until the nth area. After that, the current passes through another region b2, n in the n-th unit of the electromotive unit that has passed last, passes through each region in the reverse order from that as a starting point, and returns to the first unit of the electromotive unit. In FIG. 5A, this is repeated s / 2 times, and thus s is an even number.

Also, it is shown that the sequence br, m satisfies the recurrence formula of Expression (7). In general, the solution of equation (7) can be written as equation (8), and thus equation (2) is derived from equation (9) obtained by substituting equation (7) into equation (8).

As shown in Expression (6), the concentration of the fuel concentration in the fuel flow path decreases in proportion to the distance from the flow path supply port. Therefore, in order to reduce the difference in the concentration of fuel supplied to each unit of the electromotive section, the average distance from the flow path supply port of the flow path region 1 to the path s passing through each unit of the electromotive section is reduced. What is necessary is just to reduce the difference between the units. Therefore, the effective length from the fuel supply port of the flow channel region r (1 ≦ r ≦ s) divided by an arbitrary electromotive unit unit m (1 ≦ m ≦ n) is defined by Expression (10). .

Here, Lbr, m is the length of the flow channel region r divided by the electromotive unit unit m. Furthermore, the effective fuel concentration supplied from the flow channel to the unit m of the electromotive unit needs to be averaged in s number of flow channel regions passing through the unit m of the electromotive unit. Therefore, it can be considered that the effective fuel concentration supplied to the unit m of the electromotive portion is determined by the average length of Zbr, m defined by the equation (10) for s number of flow path regions. Would. The effective length Zm between the unit m of the electromotive section and the flow path supply port is defined by Expression (11).

Further, most ideally, all the Lbr, m may be designed to have the same length and the channels may be distributed. If Lbr, m set to the same length is assumed to be Le, an expression obtained by substituting expression (10) into expression (11) can be rewritten as expression (12) below.

Here, <Zm> represents the average of Zbr, m in the unit of the m-th electromotive portion when all Lbr, m are set to Le. Further, assuming that the length obtained by averaging <Zm> with respect to n electromotive unit units is <Z>, <Z> is defined as Expression (13). It is shown to be given.

Furthermore, if the length obtained by multiplying Le by the number sn (= h) of all the flow path regions is represented by using L0 as the effective total length of the flow path, Le can be written as in equation (15). it can. Further, <Z> defined by Expression (15) can be written as Expression (16).

Here, assuming that the average <Zm> of the effective lengths from the flow channel supply ports in all the electrode units m satisfies the inequality expression (17) described later, as shown in expression (18), The difference between <Zm> and <Zm '> with respect to arbitrary electromotive unit units m and m' falls within 10% of <Z>. Therefore, as can be seen from the above discussion, the concentration difference for each electromotive unit also falls within 10% of the average value of the fuel concentration supplied to the n electromotive units. This means that the outputs obtained from all the electromotive unit units become substantially equal, and it is possible to provide a stable and high-output fuel cell power generator.

  Next, formation of the electromotive unit of the direct methanol fuel cell will be described. By a known process (R. Ramakumar et al. J. Power Sources 69 (1997) 75), a carbon black supported on an anode catalyst (Pt: Ru = 1: 1) and a carbon black supported on a cathode catalyst (Pt) were formed. . The catalyst carrying amount was 30 for the anode and 15 for the cathode in a weight ratio to 100 carbon.

  A perfluorocarbon sulfonic acid solution (Napion solution SE-20092 from Dupont) and ion-exchanged water were added to the anode-supported carbon black formed in the above process, and the catalyst-supported carbon black was dispersed to prepare a paste. A paste was applied to 550 μm on a water-repellent treated carbon paper TGPH-120 (manufactured by E-TEK) as an anode current collector, dried, and an anode catalyst layer was formed to obtain an anode electrode.

  A perfluorocarbon sulfonic acid solution (Napion solution SE-20092 from Dupont) and ion-exchanged water were added to the cathode-supporting carbon black formed in the above process, and the catalyst-supporting carbon black was dispersed to prepare a paste. A paste was applied to 225 μm on water-repellent treated carbon paper TGPH-090 (manufactured by E-TEK) as a cathode current collector, and then dried to form a cathode catalyst layer, thereby obtaining a cathode electrode.

  A commercially available perfluorocarbon sulfonic acid membrane (Dupont Nafion 117) as an electrolyte membrane was placed between the anode catalyst layer of the anode electrode and the cathode catalyst layer of the cathode electrode, and hot pressed (125 ° C., 5 minutes, 50 kg / cm 2) on these membranes. cm2), the anode electrode, the electrolyte membrane, and the cathode electrode were joined to obtain an electromotive section unit. The cross-sectional area of the anode catalyst layer in the unit of the electromotive unit was 10 cm2. When the electromotive section was cut and the cross-sectional area was observed with an electron microscope, the thickness L of the anode catalyst layer was 105 μm, and the thickness of the cathode catalyst layer was 50 μm. In addition, the electron microscope observation confirmed that the bonding state between the anode electrode, the electrolyte membrane, and the cathode electrode was good.

  Next, evaluation of the formed electromotive section unit will be described. The formed electromotive unit was mounted on an evaluation separator, and the current-voltage characteristics were evaluated while maintaining the temperature at 70 ° C. However, operating conditions were as follows: methanol aqueous solution flow rate 0.01 cm / min, air flow rate 10 cm / min, methanol aqueous solution concentration 0.5 M, 1.0 M, 1.25 M, 1.5 M, 1.75 M, 2.0 M, 2 M The measurement was performed in the range of 0.5M. As a result, a result almost equivalent to the current-voltage characteristic obtained in FIG. 4 was obtained. It was confirmed that almost the same current-voltage characteristics could be obtained by the same evaluation method, and 100 electromotive unit units having a cross-sectional area of 10 cm2 were formed and used in experiments in the embodiment of the present invention.

[Second embodiment]
FIG. 6 is a diagram showing a main part of a direct methanol fuel cell power generation device 200 according to a second embodiment of the present invention. FIG. FIG. 4B is a bottom view, FIG. 4B is a cross-sectional view of the direct methanol fuel cell power generator 200 cut along the line β1-β1 in FIG. FIG. 2 is a cross-sectional view taken along line β2-β2 in FIG.

  In FIG. 6, 201 is an insulating flow path plate (fuel side), 202 is an insulating flow path plate (oxidant side), 203 is a fuel flow path, 204 is a fuel flow path supply port, 205 is a fuel flow path discharge port, Reference numeral 206 denotes a flow path cover on the back surface of the flow path, 207 denotes a resin sealing material, 208a and 208b denote units of an electromotive unit, 209 denotes an air flow path, and 210 denotes a flow path that does not face the units of an electromotive unit 208a and 208b. A flow path portion 211 bent toward the flow path cover 206 and a current-drawing metal thin film 211 are shown. The electromotive unit units 208a and 208b employ the structure shown in FIG. 59 described above. The fuel flow path 203 is an example in which two electromotive unit units 208a and 208b are alternately circulated (hereinafter, such a flow path configuration is referred to as an "alternate flow path"). .

  In the direct methanol fuel cell power generation device 200, fuel is supplied into the system from the fuel flow channel supply port 204, and a fuel flow channel is formed so as to alternately supply fuel to the electromotive unit units 208a and 208b. The fuel is discharged from the fuel passage outlet 205. On the other hand, the oxidant flows through the air flow path 209, and power is generated on the unit surface of the electromotive unit. In this embodiment, the fuel flow path 203 supplies fuel to the electromotive unit 208a, supplies fuel to the electromotive unit 208b, and returns to the electromotive unit 208a to supply fuel. . Thereafter, the fuel is discharged from the fuel passage outlet 205 while alternately supplying the fuel to the electromotive unit units 208a and 208b. By configuring the fuel flow path 203 in this manner, the fuel can be supplied to the electromotive unit units 208a and 208b almost uniformly and stably, so that the output is further stabilized.

  In this embodiment, in order to easily satisfy the condition of the expression (2), the number of turns s of the channel is preferably even and large, and if it is odd, s Is larger, the difference between <Zm> and <Z> becomes smaller. Therefore, it is particularly desirable that s ≧ 5.

  In the above two embodiments, the example in which the number of the electromotive unit is two has been described. However, even in a power generator having three or more electromotive unit units, the stability of the power generation output is improved by the same method. Can be.

  FIGS. 7 to 10 show examples of flow path shapes that further satisfy the condition of the expression (2). In these figures, 271 is a flow path plate, 272 is a portion where the electrode unit of the electromotive unit is disposed, 273 and 274 are supply or discharge ports of the flow path, and 275 is a flow path. In (a) to (c) of FIG. 10, two electromotive unit units are provided on both surfaces of the flow channel plate, and the power generation unit passes through a through hole 276 of the flow channel penetrating both surfaces of the flow channel. The fuel or the oxidant is alternately supplied to the electromotive unit units on both sides.

  Even in the case where the distances of the divided flow paths are largely different, the flow paths may be designed or allocated so as to satisfy the conditions of the equations (1) and (2), and the flow path width may be reduced. Even in the case of different regions, the conversion may be performed by multiplying the length by the ratio of the average width of the entire channel to the length for each region. For example, even when the part where the flow path is turned back is arranged not inside but outside the range of the electrode portion as shown in FIG. 5A, the flow path is divided as shown in FIG. , Can be assigned.

  Further, in a channel plate for supplying a fuel or an oxidizing agent to the electromotive unit disposed on both sides of the channel plate, such as that used for a monopolar type channel plate, the following Example 7 and the like also apply. Thus, the effect of the structure of the flow channel described in the present embodiment can be exerted.

(Example 1)
The above-described direct methanol fuel cell power generator 100 was subjected to a power generation test under the following conditions. That is, the initial concentration of the methanol aqueous solution fuel was 3 mol / l, the flow path plate temperature was 70 ° C., the fuel flow rate was 0.02 cm / min, and the air flow rate was 20 cm / min. This condition is hereinafter referred to as the operating condition of the first embodiment.

FIG. 11 is a diagram showing the results of the current-voltage characteristics of the direct methanol fuel cell power generator 100. As it can be seen from FIG. 11, the limit load current density in the electromotive portion unit of the channel supply port side is about 95 mA / cm ^2, to become 77mA / cm ² in the electromotive portion unit of the flow path outlet side Was observed. Therefore, when the two are electrically connected in series, a load current of substantially 77 mA / cm ² is obtained, which is approximately equal to the case where the conventional series flow path of Comparative Example 1 described later is employed. It was confirmed that the critical load current density was improved by 10%. This indicates that the fuel supply of the flow channel plate 101 is improved as compared with the conventional serial flow channel.

(Example 2)
FIG. 12 shows the results of measuring the current-voltage characteristics under the operating conditions of Example 1. As shown in FIG. 12, the value of the critical load current density of the electromotive unit unit 1 on the flow channel supply port side is about 90 mA / cm ² , and the value of the Was found to be about 87 mA / cm ² . Therefore, when both are electrically connected in series, a load current of substantially 87 mA / cm 2 can be obtained, which is about 24% as compared with the case where the conventional series flow path of Comparative Example 1 described later is employed. The improvement of the critical load current density was confirmed. In addition, in the flow path plates of the present embodiment and the first embodiment, the effective divided eight flow path areas are all equal in length, but in the present embodiment, <Z1>-<Z2 > = 0 and satisfies the condition of equation (1), but in Example 1, | <Z> − <Zm> | = 1/5 <Z> does not satisfy the condition. That is, since the flow path plate used in the second embodiment is designed so as to satisfy the expression (1), the limit load current density is greatly improved as compared with the flow path plate formed in the first embodiment. It is considered that

(Comparative Example 1)
As shown in FIGS. 13A to 13C, a direct methanol fuel cell power generator was provided with two electromotive unit units and employing a conventional series flow path. 13, the same reference numerals are given to the same functional portions as in FIG. 6, and the detailed description thereof will be omitted.

In Comparative Example 1, a parallel type flow path was used as the flow path 280 for supplying the oxidizing agent. A power generation test was performed on the stack of Comparative Example 1 under the operating conditions of Example 1, and as a result, the current-voltage characteristics shown in FIG. 14 were obtained. As can be seen from FIG. 14, the critical load current density value of the unit 208a on the flow path supply port side is about 100 mA / cm ² , and about 70 mA in the unit 208b on the flow path discharge side. / Cm ² . Therefore, when both were electrically connected in series, only a load current of 70 mA / cm ² was obtained.

(Comparative Example 2)
A direct-type methanol fuel cell power generator was configured as shown in FIGS. 15A to 15C by providing two electromotive unit units and employing a conventional parallel flow path. In FIG. 15, the same reference numerals are given to the same functional portions as in FIG. 6, and the detailed description thereof will be omitted.

  As a result of power generation of this fuel cell power generator under the operating conditions of Example 1, the current-voltage characteristics shown in FIG. 16 were obtained. FIG. 16 is a diagram in which a load current of 75 mA / cm2 is taken as an electric series circuit using two electromotive unit units, and changes over time are followed.

  FIG. 16 also shows load current characteristics when the fuel cell power generator using the flow path plate of the second embodiment is operated. The regular fine fluctuations in both plots in FIG. 16 are due to the temperature controller. From FIG. 16, when the conventional parallel type flow path is used, the output instability due to the bias of the fuel supply amount with respect to the two electromotive unit units is seen, but the flow path plate formed in Example 2 is not used. It can be seen that when used, a stable output is obtained regardless of the operation time. This result indicates that, in the conventional parallel type flow path, a stable output was not obtained because the fuel did not flow evenly at the branch portion of the pipe, but the branch of the pipe was reduced by employing the flow path plate of the present invention. This indicates that a stable output can be obtained because the fuel can be supplied uniformly because there is no fuel.

(Comparative Example 3)
FIG. 17 is a diagram showing the results of a power generation test in Comparative Example 3. Comparative Example 3 has the same flow path shape as the flow path plate formed in Example 2, but has the same length as that of the electromotive section unit 2 with respect to the total length of the effective flow path passing through the electromotive section unit 1 side. A direct methanol fuel cell power generation device was formed that formed a flow passage having an effective flow passage that was 20% shorter in total length, and provided two electromotive unit units.

  It can be seen that the difference in critical load current density between both electromotive section units is larger than that in FIG. 12 in Example 2. This is a result of the difference in the effective flow path lengths passing through the two electromotive unit units, so that the average methanol concentration supplied to each electromotive unit unit from the fuel flow path is equal. This is because the absolute amount of methanol supplied to each electromotive unit differs by 20% even when a suitable flow path shape is used. Therefore, as assumed when deriving Equation (1), and also in order to facilitate the flow path design, the effective length of the flow path region divided by each electromotive unit unit is: Should be configured to be equal.

  As described above, according to the direct methanol fuel cell power generator 300 according to the present embodiment, the output bias for each unit of the electromotive unit is reduced, and a stable fuel supply can be performed. Can be obtained.

[Fourth Embodiment]
FIG. 18 is a side view showing a direct methanol fuel cell power generator 300 according to the third embodiment of the present invention, and FIG. 20 is a perspective view, (b) is a cross-sectional view, and (a) to (e) of FIG. 20 are exploded views of the direct methanol fuel cell power generator 300, and also show cross-sectional views as appropriate.

  The direct methanol fuel cell power generation device 300 includes a first flow path plate 310, a first electromotive section layer 320, a second flow path plate 330, a second electromotive section layer 340, The laminate is formed by sandwiching a laminated body in which the third channel plate 350 is laminated with thick plates 360 and 361 made of stainless steel and tightening them with bolts 362. Reference numerals 370 to 373 denote metal terminals, which are respectively connected to carbon materials 311 and 351 described later. Further, reference numeral 374 denotes a copper wire, which makes the metal terminal 371 and the metal terminal 372 conductive.

  The first channel plate 310 is integrally molded so as to insulate two square carbon materials 311 with a thermosetting epoxy resin 312. The area and the shape of the carbon material 311 are the same as the unit of the electromotive unit to be described later. Further, a first flow path 313 for fuel formed in a concave groove is formed on the lower surface. Further, a fuel supply port 314, a fuel discharge port 315, an oxidant supply port 316, and an oxidant discharge port 317 are formed, and pipes 318a to 318d are connected to each other.

  The first electromotive section layer 320 includes two sets of electrolyte membranes 321 constituting an electromotive section unit, and an anode 322 and a cathode catalyst layer including an anode catalyst layer provided so as to sandwich the electrolyte membrane 321. A cathode electrode 323 and a sealing member 324 made of silicon rubber resin sandwiching these members are provided. The anode 322 is arranged on the upper side in the figure, and the cathode 323 is arranged on the lower side in the figure.

  The silicone rubber resin sealing member 324 cuts out supply and discharge ports of the flow passage and electrode portions of the electromotive unit to prevent fuel or oxidant from leaking from the side surface of the flow passage or the unit of the electromotive unit. Is formed. The thickness of the silicone rubber resin sealing material 324 is 0.1 mm thicker than the thickness of the anode electrode 322 and the cathode electrode 323, and the electrolyte membrane 321 is sandwiched between them.

  The distance between the anode electrodes 322 or the cathode electrodes 323 arranged in parallel was the same as the distance between the two carbon materials 311 of the first flow path plate 310.

  The second flow path plate 330 is a bipolar type flow path plate, and is integrally molded so as to insulate two square carbon materials 331 with a thermosetting epoxy resin 332. The area and the shape of the carbon material 331 are the same as the unit of the electromotive unit to be described later. A second flow path 333 for the oxidant formed in a concave groove is formed on the upper surface, and a third flow path 334 for the fuel formed in a concave groove is formed on the lower surface.

  The second electromotive section layer 340 is provided with two electromotive section units. The second electromotive section layer 340 includes two sets of electrolyte membranes 341 constituting an electromotive section unit, an anode 342 including an anode catalyst layer provided so as to sandwich these electrolyte membranes 341, and a cathode catalyst layer. A cathode electrode 343 and a sealing member 344 made of silicone rubber resin sandwiching the cathode 343 are provided. The anode 342 is arranged on the upper side in the figure, and the cathode 343 is arranged on the lower side in the figure.

  The silicone rubber resin sealing member 344 cuts out supply and discharge ports of the flow channel and electrode portions of the electromotive unit to prevent leakage of fuel or oxidant from the side surface of the flow channel or the unit of the electromotive unit. Is formed. The thickness of the silicone rubber resin sealing material 344 was 0.1 mm thicker than the thickness of the anode electrode 342 and the cathode electrode 343, and the electrolyte membrane 341 was sandwiched between them.

  The interval between the anode electrodes 342 or the cathode electrodes 343 arranged in parallel was the same as the distance between the two carbon materials 311 of the first flow path plate 310.

  The third flow path plate 350 is integrally molded so as to insulate two square carbon materials 351 with a thermosetting epoxy resin 352. The area and shape of the carbon material 351 are the same as the unit of the electromotive unit to be provided. Further, a fourth flow path 353 for the oxidant formed in a concave groove is formed on the upper surface.

  Fuel sent from a fuel pump (not shown) is supplied to a fuel supply port 314 via a pipe 318c, passes through a first flow path 313 and a third flow path 334, and passes through a pipe 318d from a fuel discharge port 315. Is discharged outside the battery. That is, fuel is supplied to the anode electrodes 322 and 342. The oxidizing agent sent from the air pump (not shown) is supplied to the oxidizing agent supply port 316 through the pipe 318a, passes through the second flow path 333 and the fourth flow path 353, and outputs the oxidizing agent outlet 317. From the battery through the pipe 318b. That is, an oxidizing agent is supplied to the cathode electrodes 323 and 343.

(Example 3)
In the direct methanol fuel cell power generator 300 as described above, when the fuel and the oxidant are supplied, the four electromotive units are electrically connected in series, so that the electronic load is supplied from the metal terminals 370 and 373. The device provides an electrical output. In addition, a gold wire having a diameter of 0.1 mm was brought into contact with the anode electrode and the cathode electrode of each electromotive unit and pulled out of the stack, and the voltage of each electromotive unit was measured.

  The operation of the direct methanol fuel cell power generator 300 is almost the same as the operation conditions of the first embodiment. However, the supply amount of the oxidizing agent and the fuel was doubled since the number of the electromotive unit units was twice that of the first embodiment. That is, the initial concentration of the methanol aqueous solution fuel was 3 mol / l, the flow path plate temperature was 70 ° C., the fuel flow rate was 0.04 cm / min, and the air flow rate was 40 cm / min. Hereinafter, this operating condition will be referred to as the operating condition of the third embodiment.

  FIG. 21 is a diagram showing the current-voltage characteristics of the direct methanol fuel cell power generator 300 described above. As can be seen from FIG. 21, the output difference between the electromotive unit units arranged in parallel in the plane direction is small, and is uniform as compared with the conventional serial type flow path and parallel type flow path of Comparative Examples 4 and 5 described later. This indicates that the fuel supply is being performed properly.

  However, there was a large difference in the value of the critical load current density between the sets of the electromotive unit units located above and below. This is because the fuel or oxidant is supplied to a set of upper and lower electromotive units by branching the pipe into two from the fuel supply port and the oxidant supply port of the stack. It is believed that the supply of fuel and oxidant to the set of fuel cells became uneven.

(Comparative Example 4)
FIGS. 22A to 22C are diagrams showing flow path plates 391 to 393 in which a series flow path is formed and incorporated in a direct methanol fuel cell power generation apparatus having four electromotive unit units. is there. Note that the flow path plate 392 is of a bipolar type. 22, the same functional portions as those in FIG. 20 are denoted by the same reference numerals, and detailed description thereof will be omitted.

  In Comparative Example 4, as compared with the value of the critical load current density obtained from the unit of the electromotive unit on the fuel supply port side, the limit load current density observed in the unit of the electromotive unit on the discharge port side as shown in FIG. Was found to decrease by about 30%. It was also found that there is a large difference in the critical load current value for the pair of upper and lower electromotive units. It is considered that this result arises from two points that the flow path shape adopts the conventional serial type flow path and that the pipe branches in the vertical direction.

(Comparative Example 5)
FIG. 24 and FIG. 25 are diagrams showing flow path plates 393 to 395 in which parallel flow paths are formed and incorporated in a direct methanol fuel cell power generation apparatus having four electromotive unit units as Comparative Example 5. . In these drawings, the same functional portions as those in FIG. 20 are denoted by the same reference numerals, and detailed description thereof will be omitted. Note that the flow path plate 394 is of a bipolar type.

  Since the parallel type is used as the flow path shape, the width of the flow path plates 393 to 39 in the short side direction is slightly widened by an amount corresponding to the branching of the pipe, and the electrolyte films 321 and 341 of the electromotive unit and the silicone rubber resin The widths of the sealing members 324 and 344 made of the same type were similarly widened.

  FIG. 26 is a diagram showing the results of measuring the current-voltage characteristics of the direct methanol fuel cell power generator configured as described above under the operating conditions of the third embodiment. As can be seen from this figure, not only did the voltage become unstable for all the electromotive unit units, but also a large difference occurred in the limit load current for the set of upper and lower electromotive unit units. This result is considered to be a result of the conventional parallel-type flow path that was not able to supply fuel uniformly at the branch portion of the pipe.

  As described above, according to the direct methanol fuel cell power generator 300 according to the present embodiment, the output bias for each unit of the electromotive unit is reduced, and a stable fuel supply can be performed. Can be obtained.

[Fourth Embodiment]
FIG. 27 is a side view showing a direct methanol fuel cell power generator 400 according to a fourth embodiment of the present invention, and FIG. 28 shows flow path plates 410, 430, 450 of the direct methanol fuel cell power generator 400. It is a top view and also shows a sectional view as appropriate.

  The direct methanol fuel cell power generator 400 includes a first flow path plate 410, a first electromotive section layer 420, a second flow path plate 430, a second electromotive section layer 440, The laminated body formed by laminating the third channel plate 450 is sandwiched between thick plates 460 and 461 made of stainless steel, and tightened with bolts 462. Note that 470 to 473 indicate metal terminals. Further, reference numeral 474 denotes a copper wire, which makes the metal terminal 471 and the metal terminal 472 conductive.

  The first flow path plate 410 is made of an acrylic resin, and has gold ribbons 411 and 412 having a thickness of 20 μm and a width of 2 mm provided on the surface thereof. In addition, a first flow path 413 for fuel formed in a concave groove is formed on the lower surface. Further, a fuel supply port 414, a fuel discharge port 415, an oxidant supply port 416, and an oxidant discharge port 417 are formed, and pipes 418a to 418d are connected to each other.

  The gold ribbons 411 and 412 are positioned substantially at the center of each electromotive section unit and take a current flow perpendicular to the flow direction in the flow path 413 in order to extract current from each electromotive section unit. It is arranged on the upper surface, one side surface, and the lower surface of the road plate 410. When the above-described gold ribbons 411 and 412 are turned over the first flow path plate 410 through the side surfaces, an electrical series state between the electromotive unit units can be realized.

  Note that other conductive members may be used instead of the gold ribbons 411 and 412. For example, it is desirable to use a material such as platinum, ruthenium, rhodium, and iridium. When a base metal is used as the base material, cover it with titanium or the like with the above-mentioned noble metal having a thickness of about 10 μm, and substitute the material. You can also.

  The first electromotive section layer 420 is configured in the same manner as the first electromotive section layer 320 of the direct methanol fuel cell power generator 300 described above, and thus detailed description is omitted.

  The second flow path plate 430 is a bipolar type flow path plate, which is formed of an acrylic resin, and provided on its surface with gold ribbons 431 and 432 having a thickness of 20 μm and a width of 2 mm. Further, a second flow path 433 for the oxidant formed in a concave groove is formed on the upper surface, and a third flow path 434 for the fuel formed in a concave groove is formed on the lower surface.

  The gold ribbons 431 and 432 are located substantially at the center of each unit of the electromotive portion and have a positional relationship perpendicular to the flow direction in the channels 433 and 434 in order to extract current from each unit of the electromotive portion. , Are arranged on the upper surface, one side surface, and the lower surface of the flow path plate 430. That is, the gold ribbons 431 and 432 are turned over the second flow path plate 430 through the side surfaces, so that the electric unit units can be electrically connected in series.

  The second electromotive section layer 440 has the same configuration as the above-described second electromotive section layer 340 of the direct methanol fuel cell power generator 300, and thus detailed description is omitted.

  The third flow path plate 450 is formed of an acrylic resin, and has gold ribbons 451 and 452 each having a thickness of 20 μm and a width of 2 mm provided on the surface thereof. Further, a fourth flow path 453 for the oxidizing agent formed in a concave groove is formed on the upper surface. When the above-described gold ribbons 451 and 452 are passed through the side surfaces to the front and back of the third flow path plate 450, an electrical series state between the electromotive unit units can be realized.

  In the direct methanol fuel cell power generator 400 configured as described above, the fuel and the oxidant are supplied and discharged similarly to the direct methanol fuel cell power generator 300 described above. Since the four electromotive unit units are electrically connected in series, an electrical output was obtained from the metal terminals 470 and 473 by the electronic load device.

(Example 4)
FIG. 29 is a diagram illustrating current-voltage characteristics when the above-described direct methanol fuel cell power generator 400 is operated under the operating conditions of the above-described third embodiment. As shown in FIG. 29, in the fourth embodiment, a stable output can be obtained as compared with the case where the conventional series-type flow path and the parallel-type flow path of the fifth and sixth examples described later are used. I understand. This result indicates that uniform fuel supply is being performed.

  Furthermore, the results of the current-voltage characteristics are the same as the experimental results of Example 3 (FIG. 21) in which the measurement was performed on the stack portion in which the same channel structure was formed of a carbon material, and only a part of the electromotive portion was conductive. It has been proved that the power generation operation can be performed just as much as using the carbon material by just bringing the members into contact. This is because the portion where the conductive portion contacts the electrode in order to extract electrical output from the electromotive portion unit does not necessarily have to be as large as possible over the entire surface of the electrode. It has been demonstrated that it is possible to sufficiently extract current by simply arranging a conductive member in part, and in particular, a small portable electronic device that does not require output with a large current. It shows that the present invention is sufficiently applicable to a battery power generator for a fuel for use.

  Further, when a flow path plate is formed by integrally molding a carbon material with an insulating resin as in a conventional laminated structure, the flow path due to a difference between members and a difference in hardness in the integration of the carbon member and the insulating resin. It is possible that a gap occurs. Further, when a carbon-resin composite material that can be molded by a mold suitable for mass production is used as the electric conductive portion, differences in the coefficient of thermal expansion, deformation temperature, and the like with the surrounding insulating resin member are considered. Consideration must be given to this. Even if the flow path is formed by cutting after being integrally molded, it is necessary to use a tool having a high hardness because it contains at least a part of the carbon material.

However, in the case of forming a bipolar type flow path plate only with a resin containing no carbon material, it is sufficient to form the flow path plate in only one step of injection molding conventionally performed. Furthermore, the advantage of the bipolar type flow path plate that the wiring is simplified by the electrical series structure in the stack stacking direction is reduced in the case of a fuel cell for a portable electric device in which thinning is important, Therefore, it is important to develop a means for insulating the flow path plates for arranging the electromotive unit units in the same plane direction. In that respect, if the flow path plate according to the present embodiment is used, it is not necessary to form a complicated flow path plate in which conductive portions and an insulating portion for insulating them from each other are integrally formed. , The moldability can be easily reduced, that is, the thickness can be easily reduced.

  As described above, according to the direct methanol fuel cell power generator 400 according to the present embodiment, the output bias for each unit of the electromotive unit is reduced, and stable fuel supply can be performed. Can be obtained.

[Fifth Embodiment]
FIG. 30 is a diagram showing first to third flow path plates 510, 530, and 550 incorporated in a direct methanol fuel cell power generator 500 (not shown) according to the fifth embodiment of the present invention. Acrylic resin, which is an insulating resin, was used as a material for each channel plate. A bipolar channel plate 510, 530, 550 having a conventional serial channel having the same shape as that of Comparative Example 4 was used. In the figure, reference numerals 511, 512, 531, 532, 551, and 552 denote gold ribbons arranged in the same manner as in the fourth embodiment, and 513, 533, 534, and 553 denote flow paths.

(Example 5)
FIG. 31 is a diagram illustrating current-voltage characteristics when the above-described direct methanol fuel cell power generation device 500 is operated under the operating conditions of the above-described third embodiment. In Example 5, the same output characteristics as in Comparative Example 4 were obtained. That is, even if the flow path plates 510, 530, and 550 are formed of an insulating resin member, and only a very small portion of the electromotive section is brought into contact with the conductive member, the power generation operation can be performed as inferior to using a carbon material. It was proved that there was.

  However, it was found that the critical load current density in the unit of the electromotive unit on the outlet side was reduced by about 30% as compared with the limit load current density in the unit of the electromotive unit on the side of the fuel supply port. This is also observed in the experimental results (see FIG. 23) for the stack of Comparative Example 4, and is considered to be not a problem of the material of the flow path plate but a result of reflecting the flow path structure.

  As described above, according to the direct methanol fuel cell power generator 500 according to the present embodiment, the output bias for each unit of the electromotive unit is reduced, and a stable fuel supply can be performed. Can be obtained.

[Sixth Embodiment]
FIGS. 32A and 32B are views showing a direct methanol fuel cell power generator 600 according to Embodiment 6 of the present invention, wherein FIG. 32A is a longitudinal sectional view, and FIG. 32B is a γ-γ line in FIG. FIG. 33 (a) to FIG. 33 (c) are sectional views taken along the arrow direction and show first to third flow path plates 610, 630, 650 incorporated in the direct methanol fuel cell power generator 600. FIG.

  The direct-type methanol fuel cell power generator 600 includes a first flow channel plate 610, a first electromotive portion layer 620, a second flow channel plate 630, a second electromotive portion layer 640, The third flow path plate 650 is formed by lamination.

  An acrylic resin, which is an insulating resin, was used as a member of the flow path plate, and a parallel type, striped flow path plate having the same flow path as in Comparative Example 5 was used. The method of disposing the conductive members was the same as in Example 4.

  Acrylic resin, which is an insulating resin, was used as a material for each channel plate. A bipolar channel plate 610, 630, or 650 having a conventional serial channel having the same shape as that of Comparative Example 4 was used. In the figure, reference numerals 611, 612, 631, 632, 651, 652 indicate gold ribbons, and 613, 633, 634, 653 indicate flow paths. The gold ribbons 611, 612, 631, 632, 651, 652 are arranged along the long sides of the flow path plates 610, 630, 650.

  The first electromotive section layer 620 is configured in the same manner as the first electromotive section layer 320 of the direct methanol fuel cell power generator 300 described above, and a detailed description thereof will be omitted. Further, the second electromotive section layer 640 is configured in the same manner as the above-described second electromotive section layer 340 of the direct methanol fuel cell power generator 300, and thus detailed description is omitted.

(Example 6)
FIG. 34 is a diagram illustrating current-voltage characteristics when the above-described direct methanol fuel cell power generator 600 is operated under the operating conditions of the above-described third embodiment. As can be seen from FIG. 34, the same output characteristics as shown in Comparative Example 5 can be obtained. That is, even if the flow path is formed of an insulating resin member and only a small part of the electromotive section is brought into contact with the conductive member, it has been demonstrated that power generation operation as inferior to using a carbon material is possible. .

  However, as shown in Comparative Examples 2 and 5, output instability due to bias in the fuel supply amount to the two electromotive unit units disposed on the same plane was observed. This result reflects the flow path structure, and is not considered to be the result of using the acrylic material.

  As described above, according to the direct methanol fuel cell power generator 600 according to the present embodiment, the bias of the output for each unit of the electromotive unit is reduced, and it is possible to perform a stable fuel supply. Can be obtained.

[Seventh Embodiment]
FIG. 35 is a side view showing a direct methanol fuel cell power generator 700 according to a seventh embodiment of the present invention, and FIG. 36 is a view showing the direct methanol fuel cell power generator 700, where (a) is a perspective view. FIG. 37B is a sectional view, and FIGS. 37A to 37C are diagrams showing first to third flow path plates 710, 730, and 750 incorporated in the direct methanol fuel cell power generator 700. is there.

  A monopolar channel plate having an alternating channel shape and made of an acrylic resin as an insulating resin was used. 36. The direct methanol fuel cell power generation device 700 includes a first flow path plate 710, a first electromotive section layer 720, a second flow path plate 730, a second electromotive section layer 740, from the upper middle in FIG. The laminated body in which the third flow path plate 750 is laminated is sandwiched between thick plates 760 and 761 made of stainless steel and tightened with bolts 762. Note that 770a to 770h indicate metal terminals.

  The first flow path plate 710 includes gold ribbons 711 and 712. On the lower surface, a first flow path 713 for an oxidizing agent formed in a concave groove shape is formed. Further, an oxidant supply port 714, an oxidant discharge port 715, a fuel supply port 716, and a fuel discharge port 717 are formed, and pipes 718a to 718d are connected thereto.

  The anode electrode 723 is arranged on the lower side in FIG. 36, and the cathode electrode 722 is arranged on the upper side. The anode electrode 743 is arranged on the upper side in FIG. 36, and the cathode electrode 742 is arranged on the lower side.

  The second channel plate 730 is a monopolar channel plate, and is formed of an acrylic material. The second flow path plate 730 is provided with a second flow path 733 for fuel formed to penetrate in the thickness direction.

  The third flow path plate 750 includes gold ribbons 751 and 752. On the upper surface, a third flow path 753 for an oxidizing agent formed in a groove shape is formed.

  Furthermore, 771a to 771e indicate copper wires, the copper wire 771a is between the metal terminals 770a and 770b, the copper wire 771b is between the metal terminals 770c and 770e, and the copper wire 771c is a metal terminal 770d. , 770f, the copper wire 771d, and the metal terminals 770g, 770i, and the copper wire 771e, between the metal terminals 770h, 770j.

  The oxidant sent from the air pump (not shown) is supplied to the oxidant supply port 714 through the pipe 718c, passes through the first flow path 713 and the third flow path 753, and flows from the oxidant discharge port 715 to the pipe. It is discharged out of the battery via 718d. That is, an oxidizing agent is supplied to the cathode electrodes 722 and 742. Further, the fuel sent from a fuel pump (not shown) is supplied to a fuel supply port 716 through a pipe 718a, and discharged from a fuel discharge port 717 through a second flow path 733 to the outside of the battery through a pipe 718b. Is done. That is, fuel is supplied to the anode electrodes 723 and 743.

  In the figure, reference numerals 711, 712, 751, and 752 indicate gold ribbons, and reference numerals 713, 733, 732, and 753 indicate flow paths. Further, an oxidant supply port 714, an oxidant discharge port 715, a fuel supply port 716, and a fuel discharge port 717 are formed, and pipes 718a to 718d are connected thereto.

  Regarding the monopolar type flow path plate located between the four electromotive sections, the flow path penetrated the flow path plate from the front to the back, and fuel was supplied to the flow path from the supply port. The thickness of the monopolar flow channel plate is set to 2 times the flow channel depth in the third embodiment so that the depth of the flow channel per unit of the electromotive unit becomes equal to the depth of the flow channel in the third embodiment. Doubled.

  The gold ribbons 711, 712, 751, 752 for extracting electrical output from each electromotive unit have the same thickness and width as in Example 4, but only the monopolar type flow path plate is insulated on the front and back. In order to make the state, the front and back of the flow path plate were not turned around. Further, in order to perform electrical wiring between the four gold ribbons of the monopolar type flow path plate, as shown in FIG. 35, gold wires 771a to 771e having a diameter of 0.1 mm are formed at the end of the flow path plate at the time of forming the stack. The ribbon was inserted between the ribbons 711, 712, 751, 752 and a silicone rubber resin sealing material.

  The electromotive section unit is installed so that the anode electrode faces the monopolar type flow path plate 730, supplies fuel to the pipe 718a so that fuel is supplied to the flow path in contact with the anode electrode, and supplies oxidant from the pipe 718c. Was supplied. In addition, a voltage was measured for each unit of the electromotive unit using a gold wire electrically connecting the units of the electromotive unit.

(Example 7)
FIG. 38 is a diagram illustrating current-voltage characteristics when the above-described direct methanol fuel cell power generator 600 is operated under the operating conditions of the above-described third embodiment. As in Examples 2, 3 and 4, it was confirmed that the effect of the alternating flow path was well reflected. Further, it can be seen that the output difference between the electromotive unit units disposed on the front and rear sides of the monopolar type flow path plate 730 is much smaller than in the third and fourth embodiments. This is because in the case of the third embodiment and the fourth embodiment, the fuel is supplied to the set of two electromotive units by the two branched flow paths, whereas in the seventh embodiment, the fuel is not branched. It is considered that the improvement was achieved by supplying fuel to the four electromotive unit units through one flow path. That is, also in the monopolar type flow path plate 730, the alternate type flow path was proved to be effective, and its validity was confirmed.

  In the monopolar type flow path plate 730, by using the flow path 733 having a shape penetrating on both sides of the flow path plate, fuel can be supplied to the electromotive unit units disposed on both sides of the flow path plate. It was confirmed from the results of this example and Examples 8 and 11 described later that the amount can be made substantially uniform. This result indicates the validity of claim 4 of the present invention. Further, by adopting a shape in which the flow path is not a parallel type, but a bent and meandering type represented by an alternate type flow path shown in the present embodiment and an eighth embodiment described later, It can be seen that more stable supply of fuel and oxidant can be performed.

  That is, by using the flow path plate according to the present embodiment, load of auxiliary equipment due to reduction of pressure loss in the flow path, prevention of stagnation of products at the time of power generation, supply of fuel and oxidant, and discharge port position For example, it is possible to flexibly design the flow path shape in consideration of the operation efficiency of the entire fuel cell power generation device. Furthermore, it was confirmed that the use of a flow path plate having an alternating flow path enables a uniform and stable output to be obtained in any of a plurality of electromotive unit units as shown in this embodiment. Was done.

  As described above, according to the direct methanol fuel cell power generator 700 according to the present embodiment, the output bias for each unit of the electromotive unit is reduced, and a stable fuel supply can be performed. Can be obtained.

[Eighth Embodiment]
FIGS. 39A and 39B are a plan view and a main part sectional view showing a direct methanol fuel cell power generator 800 (not shown) according to an eighth embodiment of the present invention. (B) is the second flow path plate 830, and (c) is the third flow path plate 850.

  As in Example 7, an acrylic resin, which is an insulating resin, was used as a member of the flow path plate to form a monopolar flow path plate having a series flow path as shown in FIG. A fuel cell power generator was constructed. In the figure, reference numerals 811, 812, 831, 832, 851, 852 indicate gold ribbons, and reference numerals 813, 833, 853 indicate flow paths.

(Example 8)
FIG. 40 is a diagram illustrating current-voltage characteristics when the above-described direct methanol fuel cell power generation device 800 is operated under the operating conditions of the above-described third embodiment. As can be seen from FIG. 40, as in Comparative Example 1, Comparative Example 4, and Example 5, the critical load current density of the unit on the outlet side of the fuel was smaller than that of the unit on the outlet side of the fuel. Although the critical load current density was reduced by about 30%, the output difference between the two sets of the electromotive unit units disposed on the front and back of the monopolar flow path plate was reduced as in the seventh embodiment. confirmed.

  As described above, according to the direct methanol fuel cell power generation device 800 according to the present embodiment, the output bias for each unit of the electromotive unit is reduced, and a stable fuel supply can be performed. Can be obtained.

[Ninth embodiment]
FIG. 41 is a plan view and a sectional view showing a flow path plate 930 incorporated in a direct methanol fuel cell power generation device 900 (not shown) according to a ninth embodiment of the present invention, as appropriate.

  A monopolar channel plate 930 was formed using an acrylic resin as an insulating resin. In the figure, reference numeral 933 denotes an alternate type flow path. Further, a reinforcing member 934 is provided in the channel 933. The reinforcing member 934 has a thickness corresponding to about 75% of the flow path depth.

(Example 9)
FIG. 42 shows the current-voltage when the above-described direct methanol fuel cell power generation device 900 and the above-described direct methanol fuel cell power generation device 700 are respectively operated continuously at 70 ° C. for 1 hour at a load current of 75 mA / cm 2. It is a figure which shows and compares a characteristic. From FIG. 42, it was confirmed that in the direct methanol fuel cell power generation device 700, there was irregular fluctuation in the voltage output. In order to elucidate the cause, a silicon rubber resin sheet was sandwiched in the stack as a dummy of a set of electromotive units located at the top of the monopolar type flow plate, and the monopolar type flow plate was visualized. . As a result, the comb-shaped structure forming the flow path is greatly inclined or slightly twisted due to the tightening pressure from the vertical direction of the flow path plate at the time of stack formation, the expansion in the thickness direction of the unit of the electromotive unit during operation, and the like. It was found that carbon dioxide bubbles generated in the flow path of the monopolar flow path plate to which fuel was supplied short-circuited the flow path. As a result, it was found that bubbles of carbon dioxide were irregularly retained in some regions of the flow path, and that shortage of fuel supply occurred irregularly in some regions of the unit of the electromotive unit.

  In the direct methanol fuel cell power generation device 900, as described above, since the reinforcing member 934 is formed, the fluctuation amplitude of the irregular voltage output as shown in FIG. It was confirmed that it could be reduced to a degree.

[Tenth embodiment]
FIG. 43 is a plan view and a sectional view showing a flow path plate 1030 incorporated in a direct methanol fuel cell power generator 1000 (not shown) according to the tenth embodiment of the present invention, as appropriate.

  A monopolar channel plate 1030 was formed using an acrylic resin as an insulating resin. In the figure, reference numeral 1033 denotes a series flow path. Further, a reinforcing member 1034 is provided in the channel 1033. The reinforcing member 1034 has a thickness of about 75% of the flow path depth.

(Example 10)
The same power generation operation test as in Example 9 was also performed on the monopolar type flow path plate having the series type flow paths adopted in Example 8, and the comb-like structure was formed by forming the reinforcing member 1030 as shown in FIG. A comparison was made with the flow channel plate for which some measures were taken. As a result, as in the case of Example 9, it was confirmed that the voltage fluctuation that appeared before the countermeasure was reduced to about 40% of that before the countermeasure.

  As described above, according to the direct methanol fuel cell power generator 1000 according to the present embodiment, the output bias for each unit of the electromotive unit is reduced, and a stable fuel supply can be performed. Can be obtained.

[Eleventh embodiment]
FIG. 44 is a view showing a flow path plate incorporated in a direct methanol fuel cell power generator 1100 (not shown) according to the eleventh embodiment of the present invention. , 1130, 1150. Acrylic resin, which is an insulating resin, was used as a material for each channel plate. A monopolar flow channel plate 1130 having parallel flow channels is used. In the figure, 1111, 1112, 1131, 1132, 1151, and 1152 indicate gold ribbons, and 1113, 1133, and 1153 indicate channels. Reference numeral 1134 denotes a reinforcing member.

  In the parallel type flow path employed in the direct methanol fuel cell power generation apparatus 600, the comb-shaped structure portion is not supported from around the flow path plate, so that the direct methanol fuel cell power generation apparatus 700 and the direct methanol fuel cell power generation It cannot be formed in a shape penetrating the front and back of the flow channel plate as in the device 800. In the direct methanol fuel cell power generator 1100, the provision of the reinforcing member 1134 enabled the formation of the flow path in a shape penetrating the front and back of the flow path plate.

(Example 11A)
FIG. 45 is a diagram illustrating current-voltage characteristics when the above-described direct methanol fuel cell power generator 1100 is operated under the operating conditions of the above-described ninth (or tenth) embodiment. As can be seen from FIG. 45, as in the case of the sixth embodiment, the output instability due to the bias of the fuel supply amount for the two electromotive unit units disposed on the same plane was observed. As in Example 8, it was confirmed that the output difference between the sets of the upper and lower electromotive units was reduced.

  Further, similarly to the ninth and tenth embodiments, the reinforcing member formed in the flow path can suppress the shift of the flow path during tightening or power generation, and can prevent short circuit or blockage between the flow paths. However, even in the case of forming a stripe-type flow path without an external manifold, the island-like portion in the flow path that separates the flow path is completely dropped from the periphery of the flow path plate. Has also been found to be very useful in preventing.

(Example 11B)
FIG. 46 is a diagram showing current-voltage characteristics when the above-described direct methanol fuel cell power generator 1100 is operated under the operating conditions of the above-described ninth or tenth embodiment. In Example 9, the voltage output fluctuation was reduced by about 50% as shown in FIG. 42 when the continuous operation was performed for 1 hour at a temperature of 70 ° C. and a current density of 75 mA / cm 2, but still a little. The fluctuation of the voltage output was observed. In this regard, when performing continuous operation under the same conditions in a visualized state, the fact that the carbon dioxide bubbles generated in the flow channel are caught and retained in the reinforcing member is a cause of the regular fluctuation of the voltage output. There was found.

  In view of the above, an attempt was made to form several types of the reinforcing member of the flow path plate employed in Example 9 in which the thickness was gradually reduced with respect to the flow path depth, and to examine the dependence on the voltage output fluctuation. .

  It is clear that when the thickness of the reinforcing member is about 50 to 40% or less with respect to the depth of the flow path, the fluctuation of the voltage is sharply reduced, and the same applies to the visualization operation of the flow path. It was confirmed that carbon dioxide did not stay for 1 second or more by the reinforcing member when the thickness was less than the thickness.

  Furthermore, the retention of carbon dioxide bubbles by the reinforcing member is more likely to occur as the cross section of the reinforcing member is perpendicular to the flow path cross section. It has also been found that it is preferable to make the cross-sectional shape of the reinforcing member opposing the plane in which the oxidant travels an acute angle.

  As described above, according to the direct methanol fuel cell power generation device 1100 according to the present embodiment, the output bias in each unit of the electromotive unit is reduced, and stable fuel supply can be performed. Can be obtained.

[Twelfth embodiment]
FIG. 47 is a view showing a channel plate 1230 incorporated in a direct methanol fuel cell power generation device 1200 (not shown) according to the twelfth embodiment of the present invention.

  In the flow path plate 1230, the gold ribbons 1231 and 1232 were laid so as to be in close contact with the reinforcing member 1234, and were further in contact with a cyanoacrylate adhesive. At the time of close contact, the adhesive was applied only to the reinforcing member so that the portions of the gold ribbons 1231 and 1232 that were in contact with the electromotive section unit were not covered with the adhesive. Reference numeral 1233 denotes a flow path.

(Example 12)
In the direct methanol fuel cell power generator 1100 using the monopolar channel plate in the above-described embodiment 11B, when the continuous operation is performed at 70 ° C. and the current density is 75 mA / cm 2 for 1 hour, the gold ribbons 1131 and 1132 are turned into the channel. It has been confirmed that the flexure in the center direction causes retention of carbon dioxide bubbles due to the flexure. In addition, after repeating the above operation several times, it was confirmed that the gold ribbons 1131 and 1132 were rarely torn due to expansion and contraction of each electromotive unit.

(Example 13)
In the direct methanol fuel cell power generation device 1200, even when the continuous operation for 1 hour at a load current of 75 mA / cm 2 at a temperature of 70 ° C. is repeated several tens of times, the deformation and displacement of the gold ribbon do not occur, and the conductive member We succeeded in preventing voltage output fluctuations and output drops due to malfunctions.

  When conducting current collection from the electromotive section with a conductive member, the conductive member must be routed in the plane direction of the flow path plate, but because it is in contact with the electromotive section, it is coated with a noble metal or a noble metal It is necessary to use a base metal member or carbon having a relatively high resistance as the conductive member. However, the longer the conductive member is drawn, the higher the cost is when the conductive member is a noble metal, and the more the electrical resistance cannot be ignored when the conductive member is a carbon material. That is, it is necessary to dispose the conductive member at a distance as short as possible, and as in this embodiment, a situation arises in which it is necessary to cross the flow path. In such a case, it is possible not only to prevent a malfunction such as a short circuit between the conductive members at the time of power generation, but also to avoid unnecessary covering of the surface of the electromotive unit unit with the conductive member. Was confirmed.

  As described above, according to the direct methanol fuel cell power generation device 1200 according to the present embodiment, the bias in output for each unit of the electromotive unit is reduced, and it is possible to perform stable fuel supply, and to achieve stable output. Can be obtained.

[Thirteenth embodiment]
FIGS. 48A and 48B are a plan view and a sectional view showing a flow path plate 1330 incorporated in a direct methanol fuel cell power generator 1300 (not shown) according to the thirteenth embodiment of the present invention. FIGS. 49A to 49C are cross-sectional views showing a flow path plate before forming a penetrating portion, and FIGS.

  The flow path plate 1330 has alternating flow paths 1333, and a reinforcing member 1334 is provided inside the flow path. As shown in FIG. 48A, between the electromotive unit units formed on the same electromotive unit unit layer, there is a portion Q of about several millimeters that is not covered by the anode electrode or the cathode electrode. Since no reaction is performed at this portion Q, it is not necessary to expose the flow channel 1333 to the surface of the flow channel plate 1330. Therefore, after leaving the boundary wall 1335 in the flow path plate 1330, a tunnel-shaped through portion 1336 is formed in the boundary wall 1335. At this time, the outlet or the inlet of the penetrating portion 1336 was formed so as to be located at a position of 1.0 mm from the end of the anode electrode or the cathode electrode toward the inside of the anode electrode or the cathode electrode.

  In the method of forming the penetrating portion 1336, as shown in FIG. 49A and FIG. 50A, the flow path 1333 is formed leaving a boundary wall 1335 which is a boundary between the electromotive unit units. At the same time, a supply port 1333a and a discharge port 1333b are formed. Next, as shown in FIG. 49B, a through hole is cut from the side surface of the boundary wall 1335 by a drill to form a through portion 1336.

(Example 13)
According to the direct-type methanol fuel cell power generator 1300 configured as described above, it is possible to prevent blockage of the flow paths, short circuit between the flow paths, or leakage of the fuel and the oxidant. That is, in the unit of the electromotive section, the electrolyte membrane may swell during operation and the seal member may be distorted. For this reason, blockage of the flow channel located between adjacent electromotive unit units in the same electromotive unit unit layer, or conversely, fuel or oxidant on the line where the end of the electromotive unit unit crosses the flow channel A short circuit may occur. For this reason, it was found that the output was reduced.

  On the other hand, when the flow path plate was formed by aligning the inlet and outlet of the tunnel-like structure with the end face of the anode electrode or the cathode electrode, passing through the gap formed at the contact portion between the cross section of the electrode and the cross section of the silicone rubber resin sealing member, The phenomenon that the oxidizer and the fuel were short-circuited between the adjacent flow paths occurred.

  Therefore, it is desirable that the entrance and the exit of the tunnel-like structure are located inside the anode electrode and the cathode electrode. However, the deeper the formed position is inside the anode electrode or the cathode electrode, the more the cathode of the flow path is formed. It is considered that the area facing the electrode is reduced and the power generation efficiency is deteriorated.

  Therefore, according to the experiment, when the inlet and the outlet are formed inside 0.5 mm, after the long-time operation test, the fuel and the oxidizing agent are rarely formed due to the expansion and contraction of the electrolyte membrane and the silicone rubber resin sealing material. A short circuit phenomenon was sometimes observed. Further, when formed within 1 mm, no defect was observed.

  From these facts, it is desirable that the inlet and outlet of the penetrating portion be located at about 1.0 mm in the inner direction of the anode electrode and the cathode electrode, and the loss of fuel supply in an area of 1 mm width around the periphery cannot be ignored. It has been found that, even when an anode electrode or a cathode electrode having a small area is employed, it is desirable that the anode electrode or the cathode electrode be positioned about 0.5 mm inward in order to prevent a short circuit or leakage.

  Regarding the shape of the alternating flow path, in order to more effectively exhibit its characteristics, it is preferable to repeatedly reciprocate or straddle a plurality of electromotive unit units or electrodes arranged in parallel on the same plane. Can be concluded. However, as a result, the flow path is more likely to face a sealing material using a silicon-based or Teflon-based member, and in particular, a tunnel-like structure in the flow path as shown in this embodiment is formed. It has been found that it is important to make the shape characteristics of the alternate channel more effective.

  Further, it has been found that such a tunnel-like structure is also effective for a flow path portion located between a supply port or a discharge port of a flow path plate and an electrode. Furthermore, it is not realistic to apply such a tunnel-like structure to a brittle member such as carbon from the viewpoint of robustness. When the above-described insulating resin member is used, the effectiveness becomes remarkable. Things.

  FIGS. 51 and 52 are plan views showing a modified example in which a boundary wall is provided in the flow path plate and a penetrating portion is provided in the boundary wall. In these figures, 1360 is a flow path, 1361 and 1362 are supply ports or discharge ports, 1363 is a reinforcing member, and 1364 is a boundary wall, and a through portion (not shown) is provided therein. Road 1360 is connected. Reference numeral 1370 denotes a range in contact with the channel plate of the anode electrode or the cathode electrode.

  As described above, according to the direct methanol fuel cell power generation device 1300 according to the present embodiment, the bias in output for each unit of the electromotive unit is reduced, and it is possible to perform stable fuel supply. Can be obtained.

[Fourteenth embodiment]
FIG. 53 is a diagram showing a channel plate incorporated in a direct methanol fuel cell power generator 1400 according to the fourteenth embodiment of the present invention.

  FIGS. 53A and 53B show a flow path plate 1400 having a penetrating portion. The flow path plate 1400 shows an example when it is formed by bonding two resin-made plate-like members 1410 and 1420, and FIG. 53B shows two examples of the flow path plate 1400. FIG. 12 is a completed view of a channel plate 1400 formed by bonding and bonding plate members 1410 and 1420. The plate-shaped member 1410 has a member main body 1411, and the member main body 1411 is formed with a portion that becomes each part of the flow path plate 1400 after assembly. 1412 is a hole forming part for forming a discharge port and a supply port, 1413 is a boundary wall forming part, 1414 is a reinforcing part forming part, 1415 is a flow path forming part, and 1416 is a comb-shaped structure part forming part.

  Similarly, the plate-like member 1420 has a member main body 1421, and the member main body 1411 is formed with a portion that becomes each part of the flow path plate 1400 after assembly. 1422 is a hole forming part for forming a discharge port and a supply port, 1423 is a boundary wall forming part, 1424 is a reinforcing part forming part, 1425 is a flow path forming part, and 1426 is a comb structure part forming part.

  The flow path forming portions 1415 and 1425 of the plate members 1410 and 1420 are formed so as to form a mirror image when they are bonded to each other. The thickness of the boundary wall forming portion 1413 is smaller than the thickness of the member main body 1411, and the surface opposite to the surface where the plate members 1410 and 1420 are bonded is flush with the surface of the plate members 1410 and 1420. It is formed as follows. The width of the flow path forming portion 1415 is formed to be the same width as the flow path forming portion 1425, and the thickness is desirably equal to or less than half of the thickness of the member main body 1411 and is equal to or more than a thickness having sufficient strength.

  The reinforcing part forming part 1414 may be formed on both of the plate-like members 1410 and 1420, or may be formed on only one of 1410 and 1420 with a total thickness of both. . However, the total thickness of the reinforcing portion forming portions 1414 and 1424 is equal to or less than half of the total thickness of the member main bodies 1411 and 1421 and is equal to or greater than 0.2 mm, and is formed so that the surfaces to be bonded have the same surface. When the reinforcing member forming portions 1414 and 1424 are formed on both of the plate members 1410 and 1420, it is preferable that the surfaces of the plate members 1410 and 1420 to be bonded are flush with the surfaces of the plate members 1410 and 1420. It is desirable to form it so that

  In bonding and attaching these plate members 1410 and 1420, it is preferable to use an adhesive made of a cyanoacrylate or polymer alloy type thermosetting resin in consideration of chemical resistance, heat resistance and water resistance. The curable epoxy resin adhesive or the like may be selected according to the compatibility of the material of the plate-like members 1410 and 1420 with the adhesive and the operating condition. Also, in order to prevent the passage from being blocked, it is desirable to apply the adhesive uniformly and as thinly as possible to the outermost surface of the plate-like members 1410 and 1420 on the adhesive surface side.

  In the flow channel plate with a through portion, it was confirmed that the blockage of the flow channel, the short circuit between the flow channels, the leakage of fuel and oxidant, etc. were resolved, but on the other hand, the cross section of the through hole was confirmed. Is a circle having a diameter smaller than the depth of the flow path, so that a remarkable change in voltage output due to stagnation of carbon dioxide bubbles as observed in Examples 12 and 13 has been observed. . The retention of carbon dioxide bubbles was at least 10 seconds or more, and a decrease in output due to carbon dioxide bubbles was observed for 30 minutes or more during the operation for a maximum of 1 hour. This is presumably because air bubbles were clogged because the cross-sectional area of the through portion in the flow path plate of Example 13 was small.

  Therefore, it is necessary to increase the cross-sectional area of the through portion, and it is technically difficult to form the through hole using a drill after forming the flow path plate as in the thirteenth embodiment. In addition, even if injection molding is used, a member with the desired cross-sectional shape is installed before molding, and it is extracted after molding. It is considered that the steps and labor for forming the part become very complicated.

  Therefore, according to the flow path plate 1400 according to the present embodiment, a flow path plate having a robust tunnel structure is formed only by bonding at least two sets of members having no through portion formed by injection molding. It becomes possible easily. In bonding the members together, it is preferable to use an adhesive made of a cyanoacrylate-based or polymer alloy-type thermosetting resin in consideration of chemical resistance, heat resistance, and water resistance.

(Example 14)
A desired through portion can be easily formed in the monopolar type flow path plate 1400 in which acrylic is used as the flow path plate member and the conductive member 1430 is formed as shown in FIG. In addition, in the one-hour continuous power generation operation under the visualization of the flow channel using the flow channel plate 1400, the retention of bubbles was at most 10 seconds or less, and a good power generation state was obtained.

  As described above, according to the channel plate 1400 incorporated in the direct methanol fuel cell power generator according to the present embodiment, it is possible to reduce the bias of the output for each unit of the electromotive unit and to perform stable fuel supply. And a stable output can be obtained.

[Fifteenth Embodiment]
FIGS. 54 (a) and (b) are views showing a flow path plate 1500 in which a penetration portion is formed, which is incorporated in a direct methanol fuel cell power generator according to a fifteenth embodiment. The flow path plate 1500 shows an example when it is formed by bonding three resin-made plate-like members 1510, 1520, and 1530, and FIG. 53B shows the flow path plate 1500 in FIG. It is a completion figure of the channel plate formed by bonding and sticking plate members 1510-1530.

  When the flow path plate is further thinned, it may be difficult to form a tunnel-like structure.However, unlike a flow path plate that requires conductivity, corrosion and extreme It is possible to provide an insulative resin thin film in close contact with the entire surface of the flow path plate without having to consider the method of forming the thin plate.

  FIG. 54 shows an example in which a flow path plate having a tunnel-like structure is formed by bonding three plate-like members 1510 to 1530. FIG. 7) is a completed view of a channel plate formed by bonding and bonding the three members of FIG.

  The plate-like member 1520 has a role as a base of a flow path when forming the flow path plate of FIG. 54B, and the plate-like members 1510 and 1530 mainly have a role of a lid for forming a through portion. . In the figure, reference numerals 1511, 1521, and 1531 denote a supply port forming part or a discharge port forming part, 1512, 1522, and 1532 denote flow path forming parts, 1523 denotes a flow path reinforcing member, 1514, 1524, and 1534 denote through-hole forming parts. Reference numerals 1525 and 1535 denote comb-shaped structure forming portions, and 1536 denotes a boundary wall where a penetrating portion is formed.

  The thickness of the plate members 1510 and 1530 is preferably not more than half the thickness of the plate member 1520 and not less than the thickness having sufficient strength, and the thickness of the reinforcing member 1523 is preferably the thickness of the completed channel plate. It is desirable that the length be equal to or less than half of the height and equal to or greater than 0.2 mm.

  The adhesive and the bonding method in bonding and bonding these plate-like members 1510 to 1530 are the same as in the case of Example 14, and the adhesive may be applied to both surfaces of the plate-like member 1520 and bonded. An adhesive may be applied to the bonding surfaces 1510 and 1530.

By the steps as described above, a 1.5 mm thick acrylic resin is used as a base member of the flow channel plate, and a polyimide resin film having a thickness of approximately 0.2 mm is used as a lid portion.
(Example 15A)
During the one-hour continuous power generation operation, the retention of carbon dioxide bubbles for several seconds or more was not observed, and a favorable power generation state could be maintained.

(Example 15B)
When the flow channel plate employed in Example 15A was formed of an acrylic resin and used in a continuous operation at a load current of 75 mA / cm 2 at 70 ° C., as shown in FIG. 55, the output gradually increased in about 3 hours. A decrease began to be observed, and almost no output was obtained after 6 hours. When the stack was disassembled after the operation was completed, it was found that the supply of the aqueous methanol fuel and the air was not normally performed due to the deformation of the members due to the temperature.

  Therefore, a flow path plate having the same shape as that of Example 15 was formed using a polycarbonate resin having a heat deformation temperature of 140 to 150 ° C., and continuous operation was performed at 70 ° C. with a load current of 75 mA / cm 2. As shown in FIG. 55, after continuous operation for about 200 hours, a decrease in output of about 10% has come to be recognized. After the stack was dismantled, the condition of the flow path plate was confirmed, and it was confirmed that fine irregularities due to the carbon paper provided for each electromotive unit were generated on the flow path plate surface, and a slight It was confirmed that distortion occurred.

  Further, in the case of the polyetherimide resin or the polyimide resin having a higher heat distortion temperature, as shown in FIG. 55, only a decrease in output of about 5% was observed even in continuous operation for 300 hours or more. After the stack was dismantled, no damage or change was observed on the surface of the flow channel plate, and the output drop of about 5% was due to the output drop of the electromotive unit itself. It became clear from the result using the road board.

  From the above results, it has been clarified that a fuel cell flow path plate capable of performing stable operation for a long period of time can be formed only with a resin member having a heat deformation temperature at least 100 ° C. higher than the operating temperature.

  The resin member used for the flow channel plate described so far needs to be one that can sufficiently withstand the temperature at which power is generated. One reason for this is that it is desirable that the long-term thermal deformation with respect to the stack and fuel temperatures during power generation be negligible, but more importantly, during actual power generation operation, The temperature of the cathode electrode surface in the electric unit is even higher than the temperature of the stack or the fuel, and depending on the operating conditions of the fuel cell power generator, the temperature may rise by 100 ° C. from the internal temperature of the stack. This indicates that in consideration of the fact that the flow path plate is in direct contact with the electromotive member, a resin member having a heat distortion temperature at a point higher by at least 100 ° C. must be used as the flow path plate. .

  Therefore, assuming that the fuel and stack environmental temperatures are 40 to 50 ° C., the polyether imide resin, polyimide resin, polyamide imide resin, polysulfone resin, polyether Sulfone resin, melamine phenol resin, and silicone resin are first desirable resin members for the flow channel plate, and then, under operating conditions of the fuel cell near room temperature, polycarbonate resin, heat-resistant vinyl ester resin, bisphenol F type epoxy resin, phenol It is preferable to use a novolak type epoxy resin, a phenol resin, a diallyl phthalate resin, a polyamide resin, a polybutylene terephthalate resin, or the like. It is also concluded that, at other temperatures, it is preferable to use a resin member 100 ° C. or more higher than the surface temperature of the stack as the flow path plate.

  As described above, according to the direct methanol fuel cell power generation device 1500 according to the present embodiment, the bias in the output for each unit of the electromotive unit is reduced, and it is possible to perform stable fuel supply. Can be obtained.

[Sixteenth embodiment]
FIG. 56 is a view showing a direct methanol fuel cell power generator 1600 according to a sixteenth embodiment of the present invention, wherein (a) is a longitudinal sectional view, (b) is a transverse sectional view, and (a) of FIG. 56) to (e) are cross-sectional views along δ1-δ1 to δ5-δ5 in FIG. 56.

  The direct type methanol fuel cell power generator 1600 uses the flow path plates adopted in Example 15 so that the flow path plates 1622 to 1624 are integrated with the piping and the fuel tank as shown in FIG. It was formed using a polyetherimide resin whose properties were verified.

  The direct methanol fuel cell power generation device 1600 includes a housing 1610, a stack 1620 held by the housing 1610, a supply unit 1630 for supplying fuel and an oxidant to the stack 1620, and a housing 1610. And a fuel and oxidizer tank portion 1650 which is detachably provided.

  The stack portion 1620 has a set of electromotive unit units in which two electromotive unit units are arranged in the horizontal direction arranged on the front and back of one monopolar flow path plate 1623. Supply methanol aqueous fuel. In the monopolar type flow path plate 1623 and the flow path plates 1622 and 1624 disposed above and below the four electromotive unit units, the flow paths 1622a and 1624a are formed only on the surface where the electromotive unit units are disposed. , Air is supplied.

  A fastening plate 1621 provided with a heat insulating material is installed on the outermost surface of the stack portion, and sealing is performed by a sealing member included in the stack by a fastening tool (not shown).

  The direct-type methanol fuel cell power generator 1600 thus configured operates as follows. That is, the air is fed to the stack portion 1610 by the air supply pump 1631, passes through the air supply passage 1632 formed on the outermost side of the monopolar flow path plate, and penetrates in the stacking direction in the portion 1633, so that the vertical flow It is branched into the flow paths of the road boards 1622 and 1624. The air and water vapor that have passed through the unit portion of the electromotive unit again merge into the outermost discharge passage 1635 of the monopolar channel plate at another through hole 1634, and flow into the space 1636 for temporarily holding the methanol aqueous solution fuel. .

  On the other hand, the methanol aqueous solution fuel is sent from the space 1636 by the solution sending pump 1641, passes through the fuel solution sending path 1642, passes through the stack, and flows into the space 1636 again with carbon dioxide. A supply path 1737 for supplying high-concentration methanol from the high-concentration methanol cartridge 1651 by the high-concentration methanol supply pump 1638 is formed in the space 1636.

(Example 16)
In operation, the initial concentration of the aqueous methanol fuel was 3 mol / l, the fuel flow rate was 0.04 cm / min, and the air flow rate was 40 cm / min. As a result of the operation, the temperature of the stack portion increased only to a temperature of about 50 ° C., but no leakage of the supplied air and the aqueous methanol solution fuel was observed, and the flow path plate including the space 4907 and the like was not observed. It was confirmed that continuous operation for 300 hours was possible without distortion or the like in 4902 and the like.

  In general, in a fuel cell power generator, the fuel container, the piping, and the stack are treated as independent components, and the whole is configured by combining these components including other components such as a pump. However, in a fuel cell power generation device applied to portable electronic devices, it is necessary to simplify the structure and to reduce the thickness of the device. Therefore, regarding the included stack, it is preferable to greatly reduce the number of laminations and arrange the electromotive units in parallel so that the plane direction of the electromotive unit unit is parallel to a direction perpendicular to the thickness of the device. Become. At the same time, it is necessary to reduce the thickness of the piping for supplying and discharging the fuel or the oxidizing agent to and from the stack. Also means that it will be extremely difficult. Furthermore, it is difficult to maintain the robustness of the device because of the reduced thickness. It is preferable and sufficient that the fuel container and piping are made of resin.However, in a situation where it is necessary to specialize in making the entire device thinner, when forming each component independently, the stack Consideration must also be given to the structure for connecting the fuel or oxidant supply or discharge port to the fuel container or pipe, and the structure for increasing the overall robustness.

  On the other hand, in the direct methanol fuel cell power generator 1600, a part of a pipe or a fuel container is formed as an extension of the flow path plate, that is, the tank or the pipe is formed by integral molding with the same resin member as the flow path plate. As a result, the number of components can be significantly reduced, and the structural robustness of the fuel cell power generation device can be easily obtained by integration, and the productivity can be greatly improved. When the channel plate is made of a material or metal mainly composed of carbon, it is very difficult. Therefore, the material of the channel plates 1622 to 1624 is required to be a resin material.

  As described above, according to the direct methanol fuel cell power generation device 1600 according to the present embodiment, it is possible to reduce the bias of the output for each unit of the electromotive unit, to perform stable fuel supply, and to obtain a stable output. Can be obtained.

  In the direct methanol fuel cell power generation device 1600 described above, a part of the power output obtained from the electromotive unit unit group is supplied to the liquid sending pump 1641, the high-concentration methanol supplying pump 1638, and the air sending pump 1631. , An electric circuit 1660 for supplying the remaining power output to an external electric device.

  Note that FIG. Reference numeral 1661 of 56A denotes a gas-liquid separation mechanism for separating only gas components from the exhaust from the anode electrode, and 1660 denotes a liquid sending pump 1641 and a high-concentration methanol supply for part of the electric power output obtained from the unit group of the electromotive unit. It shows an electric circuit that supplies a power pump 1638 and an air supply pump 1631 and supplies at least a part of the remaining power output to an external electric device.

  Thus, even when a part of the electric power output was supplied to the external electric equipment, it was confirmed that a favorable power generation operation could be performed similarly to the sixteenth embodiment.

  In FIG. 58, in the direct methanol fuel cell power generator 1600, a load current output for each of the four electromotive units was set to 0.75 A, and a power generation test was performed by changing the methanol aqueous solution fuel concentration and the fuel flow rate. The supply amount of air was 240 ml / min.

  As is clear from the formula III or the formulas 3 and 4, in the power generation, six electrons are obtained from one molecule of a pair of methanol and water, so that a current of 1 A is obtained by a single electromotive unit unit. In this case, 1.725 (mol / s) of methanol and water are theoretically required at minimum. Further, in the case of having n electromotive unit units electrically wired in series or in parallel with each other, a supply amount of 1.725 × n (mol / sec) is required as a theoretical amount.

  This means that in order to obtain a current of 1 A from a single electromotive unit unit, a theoretical supply of 34.5 (μl / min) is required when using a fuel having a concentration of 3 mol / l, and 2 mol / l 51.8 (μl / min) when using a fuel having a concentration of l, 104 (μl / min) when using a fuel having a concentration of 1 mol / l, and 25.9 when using a fuel having a concentration of 4 mol / l. (Μl / min) of theoretical supply is required.

  Further, when there are n units of the electromotive unit and a current of 1 A is obtained from each of them, a supply amount of n times these supply amounts is required as a total amount.

From FIG. 58, at the fuel concentration of 3 mol / l, the maximum voltage is obtained at the supply amount of the methanol aqueous solution fuel of about 0.17 ml / min, and similarly, at the fuel concentration of 2 mol / l, about 0.3 ml / min. It can be seen that the maximum value was not obtained even at 0.8 ml / min at a fuel concentration of 1 mol / l at a supply amount of 1 mol / l. On the other hand, at the fuel concentration of 4 mol / l, the maximum value is obtained at about 0.12 ml / min, but slightly lower than the value at 3 mol / l, and it can be seen that the maximum value is significantly reduced at 5 mol / l. Table 1 summarizes these results.

  As can be seen from Table 1, the maximum voltage obtained at each concentration cannot be reached or no voltage can be obtained, and at a supply amount of about 1.5 to 2.0 times the theoretical amount, 90% or more of the maximum voltage is obtained. Is obtained. However, when the supply amount is larger than the above, a unilateral decrease in voltage is observed.

  Further, at a concentration of about 4 mol / l or more, the maximum voltage value is remarkably reduced with an increase in the concentration, and it is preferable to use a methanol aqueous solution fuel concentration of about 5 mol / l or less at the highest. Therefore, in order to reduce the pressure loss received from the flow path plate and to save the power consumption of the auxiliary device, it is necessary to use a methanol aqueous solution fuel concentration of at least 1 mol / l or more. Is preferable.

In summary, n is the number of electromotive unit units included in the electromotive unit unit group, I is the current output for each electromotive unit unit, and C _MeOH is the concentration (mol / l), Y is the total amount (l / min) of the aqueous methanol fuel supplied to the electromotive unit unit group, and when the temperature of each electromotive unit is in the range of 40 ° C to 70 ° C,
Y ≦ Y ₀ × 2 (101)
Y ₀ = 1.04 × 10 ⁻⁴ × nI / C _MeOH (102)
1.0 ≦ C _MeOH ≦ 5.0 (103)
That is, it is understood that the conditions of the methanol aqueous solution fuel concentration and the supply amount satisfying the expressions (101) to (103) are appropriate.

  In the above-described embodiments and examples, only the fuel flow path is of the alternating type, but the air flow path may be of the alternating type. Further, both the fuel flow path and the air flow path may be of an alternating type.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying constituent elements in an implementation stage without departing from the scope of the invention. Various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the above embodiments. For example, some components may be deleted from all the components shown in the embodiment. Further, components of different embodiments may be appropriately combined.

FIG. 1 is a perspective view illustrating a direct methanol fuel cell power generator according to a first embodiment of the present invention. The figure which shows the principal part of the direct type methanol fuel cell power generator. The bottom view showing the channel board concerning the 1st modification of the same channel board. FIG. 3 is a characteristic diagram showing the dependence of current-voltage characteristics on the initial concentration of an aqueous methanol solution in units of electromotive units of a direct methanol fuel cell. FIG. 4 is an explanatory view schematically showing a method of allocating a fuel flow path. The figure which shows the principal part of the direct methanol fuel cell power generation device which concerns on 2nd Embodiment of this invention. The top view which shows the modification of a flow path plate. The top view which shows the modification of a flow path plate. The top view which shows the modification of a flow path plate. The figure which shows the modification of a flow path plate. The figure which shows the result of the current-voltage characteristic of a direct type methanol fuel cell power generator. FIG. 4 is a diagram showing a result of measuring current-voltage characteristics under operating conditions of Example 1. The figure which shows the direct-type methanol fuel cell power generator using a serial type flow path. FIG. 4 is a diagram showing current-voltage characteristics of Comparative Example 1 under operating conditions of Example 1. The figure which shows the direct type methanol fuel cell power generator using the parallel type flow path. FIG. 4 is a diagram illustrating current-voltage characteristics under operating conditions according to the first embodiment. The figure which shows the result of the electric power generation test in the comparative example 3. The side view showing the direct type methanol fuel cell power generator concerning a 3rd embodiment of the present invention. It is a figure which shows the same direct type methanol fuel cell power generator, (a) is a perspective view, (b) is a cross-sectional view. FIG. 2 is an exploded view of the direct methanol fuel cell power generator. The figure which shows the current-voltage characteristic of the direct methanol fuel cell power generator. The figure which shows the flow-path plate in which the series-type flow path formed in the direct-type methanol fuel cell power generator provided with four electromotive part units was formed. FIG. 14 is a view showing an experimental result regarding the stack of Comparative Example 4. The figure which shows the flow-path plate in which the parallel flow path formed in the direct-type methanol fuel cell power generation apparatus provided with four electromotive part units as Comparative Example 5 was formed. The figure which shows the flow-path plate in which the parallel flow path formed in the direct-type methanol fuel cell power generation apparatus provided with four electromotive part units as Comparative Example 5 was formed. FIG. 8 is a diagram showing the results of measuring current-voltage characteristics under operating conditions of Example 3. The side view showing the direct type methanol fuel cell power generator concerning a 4th embodiment of the present invention. FIG. 4 is a plan view showing a flow channel plate of the direct methanol fuel cell power generator. FIG. 9 is a diagram showing current-voltage characteristics when the direct methanol fuel cell power generator was operated under the operating conditions of Example 3. The figure which shows the 1st-3rd channel plate incorporated in the direct methanol fuel cell power generation device which concerns on 5th Embodiment. FIG. 9 is a diagram showing current-voltage characteristics when the direct methanol fuel cell power generator was operated under the operating conditions of Example 3. It is a figure showing the direct type methanol fuel cell power generator concerning a 6th embodiment of the present invention, (a) is a longitudinal section, and (b) cuts by γ-γ rays in (a) and shows an arrow. Sectional view seen in the direction. The figure which shows the 1st-3rd channel plate incorporated in the direct type methanol fuel cell power generator. FIG. 9 is a diagram showing current-voltage characteristics when the direct methanol fuel cell power generator was operated under the operating conditions of Example 3. The side view showing the direct type methanol fuel cell power generator concerning a 7th embodiment of the present invention. It is a figure which shows a direct type methanol fuel cell power generator, (a) is a perspective view, (b) is sectional drawing. It is a figure which shows the 1st-3rd channel plate incorporated in the direct type methanol fuel cell power generator. FIG. 9 is a diagram showing current-voltage characteristics when the direct methanol fuel cell power generator was operated under the operating conditions of Example 3. The top view and principal part sectional drawing which show the direct type methanol fuel cell power generator which concerns on 8th Embodiment of this invention. FIG. 9 is a diagram showing current-voltage characteristics when the direct methanol fuel cell power generator was operated under the operating conditions of Example 3. The top view and principal part sectional drawing which show the channel plate built in the direct type | mold methanol fuel cell power generation device which concerns on 9th Embodiment of this invention. The figure which shows the current-voltage characteristic of the direct type methanol fuel cell power generator in comparison. The top view and principal part sectional drawing which show the channel plate built in the direct type methanol fuel cell power generation device which concerns on 10th Embodiment of this invention. The figure which shows the flow-path plate incorporated in the direct methanol fuel cell power generation device which concerns on 11th Embodiment of this invention. The figure which shows the current-voltage characteristic at the time of driving | running | working the direct methanol fuel cell power generator under the operating conditions of Example 9. The figure which shows the current-voltage characteristic at the time of driving | running | working the direct methanol fuel cell power generator under the operating conditions of Example 9. The figure which shows the flow-path plate incorporated in the direct methanol fuel cell power generator concerning the 12th Embodiment of this invention. The top view and principal part sectional drawing which show the channel plate built in the direct methanol fuel cell power generation device which concerns on 13th Embodiment of this invention. The figure which shows the flow path board before a penetration part formation. Sectional drawing which shows a penetration part formation process. The top view which shows the modification of the flow path plate which provided the penetration part in the boundary wall. The top view which shows the modification of the flow path plate which provided the penetration part in the boundary wall. The figure which shows the flow-path plate incorporated in the direct methanol fuel cell power generator concerning the 14th Embodiment of this invention. The figure which shows the flow-path board in which the penetration part built in the direct type | mold methanol fuel cell power generation apparatus which concerns on 15th Embodiment of this invention is formed. The figure which shows the current voltage characteristic in the direct type methanol fuel cell power generator. It is a figure showing the direct type methanol fuel cell power generator concerning a 16th embodiment of the present invention, (a) is a longitudinal section, and (b) is a cross section. FIG. 57 is a cross-sectional view taken along δ1-δ1 to δ5-δ5 in FIG. 56. The figure which shows the relationship between the voltage and the fuel supply amount in the direct methanol fuel cell power generator for every fuel concentration. FIG. 3 is an explanatory diagram schematically showing a configuration of a general electromotive unit unit.

Explanation of reference numerals

  Reference Signs List 100 direct methanol fuel cell power generator, 101 insulating channel plate, 102 insulating channel plate, 103 fuel channel, 104 fuel channel supply port, 105 fuel channel discharge port, 106 Flow path lid, 107: resinous sealing material, 108a, 108b: unit of electromotive unit, 109: air flow path.

Claims (17)

An electromotive unit unit group including a plurality of electromotive unit units formed by sandwiching an electrolyte membrane between an anode including an anode catalyst layer and a cathode including a cathode catalyst layer,
A first flow path plate which is arranged in contact with the anode electrode of the electromotive unit unit group and in which a first flow path through which fuel flows is formed;
A second flow path plate which is arranged in contact with the cathode electrode of the electromotive unit unit group and in which a second flow path through which the oxidant flows is formed,
The first flow path passes without contacting all the anode electrodes of the electromotive unit unit group without branching from the inlet to the outlet thereof, and passes through the anode electrode of at least one electromotive unit unit. Is a direct-type liquid fuel cell power generation device characterized in that it is formed so as to contact a plurality of times. An electromotive unit unit group including a plurality of electromotive unit units formed by sandwiching an electrolyte membrane between an anode including an anode catalyst layer and a cathode including a cathode catalyst layer,
A first flow path plate which is arranged in contact with the cathode electrodes of these electromotive unit unit groups and in which a first flow path through which the oxidant flows is formed;
A second flow path plate which is disposed in contact with the anode electrode of the electromotive unit unit group and in which a second flow path through which fuel flows is formed,
The first flow path passes without contacting all the cathodes of the electromotive unit unit group without branching from the inlet to the outlet thereof, and passes through the cathode of at least one electromotive unit. Is a direct-type liquid fuel cell power generation device characterized in that it is formed so as to contact a plurality of times. n is the number of electromotive unit units included in the electromotive unit unit group, s is the number of times the first flow path passes through each electromotive unit unit, and h is the number of flow path regions, and n and s Br, m (1 ≦ m ≦ n, 1 ≦ r ≦ s) is a number assigned to the flow path area and is a natural number equal to or less than h, and Zbr, m is a flow path supply port of each flow path area. When L0 indicates the effective length of the first flow path,

The direct liquid fuel cell power generator according to claim 1 or 2, wherein the following conditions are satisfied. A first and a second electromotive unit unit group formed by sandwiching an electrolyte membrane between an anode including an anode catalyst layer and a cathode including a cathode catalyst layer;
A first flow path plate which is arranged in contact with the anode electrode of the first electromotive unit unit group and in which a first flow path through which fuel flows is formed;
A second flow path is formed on one surface of the first electromotive unit unit group in contact with the cathode electrode of the first electromotive unit unit group and through which the oxidant flows, and the second electromotive unit unit is formed on the other surface. A second flow path plate in which a third flow path through which the oxidant flows while being in contact with the cathodes of the group is formed;
A third flow path plate which is disposed in contact with the anode electrode of the second electromotive unit unit group and in which a fourth flow path through which fuel flows is formed;
An external electrode provided for connection with the outside,
The first to third flow path plates are formed of an insulating member,
The first to third flow path plates are formed with a conductive portion that conducts between the anode electrode and the cathode electrode of the first and second electromotive unit unit layers or with the external electrode. Characteristic direct-type liquid fuel cell power generator. A first and a second electromotive unit unit group formed by sandwiching an electrolyte membrane between an anode including an anode catalyst layer and a cathode including a cathode catalyst layer;
A first flow path plate disposed in contact with the cathode electrode of the first electromotive unit unit group and formed with a first flow path through which the oxidant flows;
A second flow path is formed on one surface side of the first electromotive unit unit group in contact with the anode of the first electromotive unit unit and through which fuel flows, and on the other surface side, the second electromotive unit unit group is formed. A second flow path plate in which a third flow path through which fuel flows while being in contact with the anode electrode of
A third flow path plate disposed in contact with the cathode electrode of the second electromotive unit unit group and having a fourth flow path through which an oxidant flows,
An external electrode provided for connection with the outside,
The first to third flow path plates are formed of an insulating member,
The first to third flow path plates are formed with a conductive portion that conducts between the anode electrode and the cathode electrode of the first and second electromotive unit unit layers or with the external electrode. Characteristic direct-type liquid fuel cell power generator.   The second flow path plate has a shape in which the flow path is bent or meandering in a plane direction of the flow path plate, and penetrates in a thickness direction of the second flow path plate. The direct liquid fuel cell power generator according to claim 4 or 5, wherein one flow path is formed by the flow path and the third flow path.   7. The direct liquid fuel cell power generator according to claim 6, wherein the second flow path plate has a reinforcing member for maintaining a cross-sectional shape of each flow path formed in the flow path.   The direct type liquid fuel cell power generator according to claim 7, wherein the reinforcing member has a cross-sectional area of 50% or less of a cross-sectional area of the flow path and a thickness of 0.2mm or more.   9. The direct liquid fuel cell power generator according to claim 7, wherein the reinforcing member forms a part of the conductive portion.   The flow channel plate has a through portion formed in a tunnel shape between portions of the flow channel that are in contact with the anode electrode or the cathode electrode, and an outlet or an inlet of the through portion has the The direct-type liquid according to claim 4, wherein the liquid is disposed within a range from 0.5 mm to 1.0 mm inward of the anode or the cathode from an end of the anode or the cathode. Fuel cell power generator.   The flow path plate has a through portion formed in a tunnel shape between a portion of the flow path that is in contact with the anode electrode or the cathode electrode and a supply port or a discharge port of the flow path. An outlet or an inlet of the penetrating portion is arranged in a range from an end of the anode electrode or the cathode electrode to an inner side of the anode electrode or the cathode electrode in a range of 0.5 mm or more and 1.0 mm or less. The direct type liquid fuel cell power generator according to claim 4 or 5, wherein   6. The direct liquid fuel cell power generator according to claim 4, wherein the flow path plate is formed by bonding a plurality of insulating resin members.   The insulating member is a polyetherimide resin, a polyimide resin, a polyamideimide resin, a polysulfone resin, a polyethersulfone resin, a melamine / phenol resin, a silicone resin, a polycarbonate resin, a heat-resistant vinyl ester resin, a bisphenol F type epoxy resin, and a phenol novolac type. The direct resin according to claim 4, wherein the resin member is formed of any one of an epoxy resin, a phenol resin, a diallyl phthalate resin, a polyamide resin, and a polybutylene terephthalate resin, or a combination of a plurality of different resin members. Type liquid fuel cell power generator.   The direct type liquid fuel cell power generator according to claim 4 or 5, wherein a space for temporarily storing the fuel or the oxidant is integrally formed in the flow path plate. An anode electrode including an anode catalyst layer;
A cathode electrode including a cathode catalyst layer,
A fuel container including at least two electromotive unit units including an electrolyte membrane disposed between the anode and the cathode, and a fuel container,
A flow path plate formed with a flow path for supplying an oxidant or fuel to the electromotive unit unit,
The flow channel is a flow channel that returns from the fuel container to the first electromotive unit unit via the first electromotive unit unit and the second electromotive unit unit, and a branch is formed between the flow channels. A direct-type liquid fuel cell power generation device having a flow path that is not affected. n is the number of electromotive unit units included in the electromotive unit unit group, I is the current output for each electromotive unit unit, C _MeOH is the concentration of the supplied methanol aqueous solution fuel (mol / l), Y Is the total amount (l / min) of the aqueous methanol fuel supplied to the electromotive unit unit group, and when the temperature of each electromotive unit is in the range of 40 ° C to 70 ° C,
Y ≦ Y ₀ × 2 (101)
Y ₀ = 1.04 × 10 ⁻⁴ × nI / C _MeOH (102)
1.0 ≦ C _MeOH ≦ 5.0 (103)
The direct-type liquid fuel cell power generator according to any one of claims 1 to 15, wherein: A liquid fuel supply device that supplies liquid fuel to the flow path plate that contacts the anode electrode of the electromotive unit unit group,
An oxidant supply device that supplies an oxidant to the flow path plate that contacts the cathode electrode of the electromotive unit unit group;
A liquid fuel container that contains liquid fuel and supplies liquid fuel to the liquid fuel supply device;
A gas-liquid separation mechanism that separates only gas components from the exhaust from the anode electrode,
A part of the power output obtained from the electromotive unit unit group is supplied to the liquid fuel supply device and the oxidant supply device, and at least a part of the remaining power output is supplied to an external electric device. The direct type liquid fuel cell power generator according to claim 1, further comprising a circuit.

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