JP2007324012A - Electrochemical device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrochemical device such as a fuel cell having excellent power generation efficiency and capable of manufacturing simply. <P>SOLUTION: The fuel cell 12 has a plane arrangement structure 11A in which a plurality of power generation parts 1 consisting of an electrolyte membrane 3 and a positive electrode 4 and a negative electrode 5 pinching this electrolyte membrane 3 are arranged with a given spacing along the surface direction. The exposed parts 3a of the electrolyte membrane 3 protruding oppositely from the positive electrode 4 and the negative electrode 5 between a plurality of mutually adjoining power generation parts 1 are embedded in an adhesive layer (seal) 2 of gas barrier property, and thereby the plurality of the power generation parts 1 are connected. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electrochemical device such as a fuel cell suitable as a power source for a small electronic device.

  Currently, various primary batteries and secondary batteries are used as power sources for electronic devices. One method of determining the characteristics of these batteries is energy density. This energy density is the energy capacity per unit mass or unit volume of the battery.

  In recent years, as electronic devices have become smaller and higher in performance, the need for higher capacity and higher output power, particularly higher capacity, has been increasing. With batteries, it has become difficult to supply sufficient energy to drive electronic devices. As a solution to overcome this situation, the development of a battery having a higher energy density is urgently required, and the fuel cell is attracting attention as one of the candidates.

  The fuel cell includes a negative electrode (anode), a positive electrode (cathode), an electrolyte, and the like, and fuel is supplied to the negative electrode side, and air or oxygen is supplied to the positive electrode side. Then, a redox reaction of the fuel occurs on the negative electrode and the positive electrode, and a part of the chemical energy of the fuel is converted into electric energy and taken out.

  Various types of fuel cells have already been proposed or prototyped, and some are practically manufactured and used. Depending on the electrolyte used, these fuel cells may be, for example, alkaline electrolyte fuel cells (AFC), phosphoric acid fuel cells (PAFC), molten carbonate fuel cells (MCFC), solid oxide fuel cells (SOFC). ) And polymer electrolyte fuel cell (PEFC).

  For example, a polymer electrolyte fuel cell 62A shown in FIG. 7 employs an electrolyte membrane (electrolyte) 51 made of a polymer ion exchange membrane (cation exchange membrane). For example, a membrane / electrode assembly (power generation unit) 54 in which a negative electrode 52 and a positive electrode 53 each having a noble metal-based electrode catalyst layer bonded to a base material mainly made of carbon, for example, is provided on both sides of the electrolyte membrane 51. A unit cell (fuel cell) sandwiched between two fuel supply units is provided.

  Normally, this unit cell is used as a fuel cell stack by stacking a predetermined number of unit cells because the voltage that can be taken out is low (0.3V-0.8V) when used alone.

  In this type of fuel cell 62A, when a fuel gas, for example, a gas mainly containing hydrogen is supplied to the negative electrode 52 side, hydrogen is ionized on the electrode catalyst, and the positive electrode 53 side passes through the electrolyte membrane 51. Move to. Electrons generated during that time are taken out by the external circuit 61 and used as direct current electric energy. The positive electrode 53 is supplied with an oxidant gas, for example, a gas or air mainly containing oxygen, so that hydrogen ions, electrons, and oxygen react in the positive electrode 53 to generate water.

  On the other hand, in a fuel cell that prefers a thin structure such as a direct methanol fuel cell for mobile use, a plurality of unit cells are arranged in a row or a plurality of rows in a planar shape, and the unit cells are electrically connected in series. In many cases, a planar stacked fuel cell is employed.

  In that case, in order to serialize a predetermined number, the number of cells required, for example, an electrode size hole that can fit only the electrode portion into an insulating substrate (gasket) such as Teflon (registered trademark). A plurality of units are provided, and unit cells are fitted therein to form a planar array structure, thereby producing a fuel cell. At this time, an electrolyte membrane cut larger than the size of the electrode portion of the unit cell is sandwiched between the insulating substrates, and pressure is applied by a predetermined means to physically adhere to form a seal portion, thereby providing insulation and Gas sealability is secured.

  However, since the sealing portion is formed by physical adhesion between the electrolyte membrane and the insulating substrate, in order to improve the sealing performance, the portion of the electrolyte membrane that becomes the sealing portion can be increased, or the electrolyte of the insulating substrate can be increased. For example, the pressing pressure on the membrane must be increased. For this reason, there is a disadvantage that the casing of the unit cell is large and thick.

  In addition, since the solid polymer electrolyte membrane has a characteristic of expanding and contracting depending on the amount of water, the sealing performance of the seal portion becomes unstable due to a change in the amount of water during power generation, and it is difficult to maintain gas sealing performance. Due to this poor gas sealing performance, the fuel cells generate heat and the fuel is wasted.

  Therefore, as a method for solving these problems, a fuel cell 62B having a structure as shown in FIG. 8 has been proposed (see Patent Document 1 described later).

  In this structure, in a predetermined portion of the electrolyte membrane 51 (proton conducting portion) of the membrane-electrode assembly (MEA) 54B, the proton of the sulfonic acid group is replaced by a metal ion or ammonium ion, and the insulating layer (proton insulating portion) ) 63 is formed and held between the rubber packings 64.

Patent Publication No. 2894378 (page 2, right column, line 34 to page 3, left column, line 28, FIG. 2)

  However, in the fuel cell 62B having the structure shown in FIG. 8, the ions introduced into the insulating layer (proton insulating portion) 63 move to the electrolyte membrane (proton conducting portion) 51 during long-term power generation. The output of Furthermore, the process for forming the insulating layer (proton insulating part) 63 is complicated.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an electrochemical device such as a fuel cell that has good power generation efficiency and can easily produce a planar array structure. There is.

  That is, according to the present invention, a plurality of membrane / electrode assemblies comprising an electrolyte membrane and a first electrode and a second electrode sandwiching the electrolyte membrane are arranged along a plane direction at a predetermined interval. In the electrochemical device, an exposed portion of the electrolyte membrane that protrudes from the first electrode and the second electrode between a plurality of adjacent membrane-electrode assemblies is embedded in a gas barrier adhesive layer. Thus, the present invention relates to an electrochemical device characterized in that a plurality of the membrane-electrode assemblies are connected.

  According to the present invention, the exposed portion of the electrolyte membrane protruding in opposition from the first electrode and the second electrode between a plurality of adjacent membrane-electrode assemblies is insulative and has a gas barrier property. Embedded in the plurality of membrane-electrode assemblies connected to each other, there is no movement of undesired substances from the adhesive layer to the membrane-electrode assembly, so there is no short circuit between the electrodes, As a result, the gas sealing property is improved, and as a result, the reliability of the device is high, and for example, an electrochemical device having good power generation efficiency can be obtained.

  In addition, by embedding and connecting the exposed portions of the facing electrolyte membrane in the adhesive layer, a high-output and thin structure in which a plurality of membrane-electrode assemblies are arranged at high density along the surface direction can be simplified. Can be produced.

  In the present invention, in order to make an electrochemical device in which the plurality of membrane-electrode assemblies are arranged in an advantageous flat shape, the plurality of membrane-electrode assemblies are arranged on the same surface, and the adhesive layer It is preferable that both sides of the surface are flat.

  Alternatively, the bonding is performed in a state where the plurality of membrane / electrode assemblies are arranged at positions shifted in the thickness direction (that is, a state where the exposed portions of the electrolyte membrane are overlapped via the adhesive layer). Even if both sides of the layer are flat, the device can be substantially flat without a short circuit between the electrolytes.

  Further, in order to improve the adhesion between the electrolyte membrane and the adhesive layer, it is preferable that the adhesive layer is formed by adhering at least two layers of film-like resin. It is desirable that the film-like resin is made of a thermoplastic resin, and the exposed portion of the electrolyte membrane and the adhesive layer are bonded by heating the film-like resin.

  Alternatively, in order to improve the adhesion between the electrolyte membrane and the adhesive layer, the film-like resin has an acid, an acid anhydride, an acid ester, a metallocene, and a hydroxyl group on the adhesive surface with the exposed portion of the electrolyte membrane. It is preferably modified with at least one selected from the group consisting of (or esterified products thereof) and the like.

  In addition, in order to improve the adhesion between the exposed portion of the electrolyte membrane and the adhesive layer, the film-like resin can be bonded with a hydroxyl group or imidazole that can be bound by an interaction such as electrostatic interaction with a sulfonic acid group of the electrolyte. It is preferable to polymerize molecules having a basic substituent such as pyridine, amine and the like.

  The electrochemical device of the present invention is preferably configured as a fuel cell comprising a negative electrode or a fuel electrode (anode), an electrolyte layer, and a positive electrode or an oxygen electrode (cathode).

  Hereinafter, preferred embodiments of the present invention will be described specifically and in detail with reference to the drawings.

First Embodiment FIGS. 1 to 5 show a first embodiment of the present invention.

  A fuel cell 11A as an electrochemical device according to the present embodiment will be described based on the manufacturing process shown in the cross-sectional view of FIG. 1 and the perspective view of FIG.

  First, as shown in FIG. 1 (a), the openings 13a for accommodating the individual power generation units 1 by being fitted at a plurality of locations (three locations in the cross section, two rows: the same applies hereinafter) are thermoplastic. It forms in the resin sheet 2a (film-like resin). These openings can be formed by cutting (hereinafter the same).

  Next, as shown in FIG. 1B, the membrane / electrode assembly 1 including the electrolyte membrane 3, the positive electrode 4 (gas diffusion electrode), and the negative electrode 5 (gas diffusion electrode) is fitted into each opening 13a. However, in the joined body 1 (MEA) as the power generation part, a part 3a of the electrolyte membrane 3 is exposed to protrude around each electrode, and the exposed part is received around the opening part 13a, and in the opening part 13a. The negative electrode 5 is fitted into the.

  Thus, after each power generation unit 1 is accommodated and held in each opening 13a, as shown in FIG. 1C and FIG. 2, the above-described protruding exposure of the electrolyte membrane 3 from the top of the sheet 2a on the positive electrode 4 side. The thermoplastic resin sheet 2b (film-like resin) covering the portion 3a and having an opening 13b for fitting the positive electrode 4 is covered, and the exposed portion 3a of the electrolyte membrane 3 is sandwiched between the sheet 2a. At this time, the plurality of power generation units 1 are arranged on the same surface, and both surfaces of the sheets 2a and 2b are flat.

  Next, as shown in FIG. 1 (d), only the sheets 2a and 2b are heated and bonded together by thermocompression, thereby forming an adhesive layer 2 (that is, a seal) having sufficient gas barrier properties. The adhesive layer 2 is attached to the electrolyte membrane 3 exposed from the electrode and a part of the electrode, thereby burying the exposed exposed portion 3a of the electrolyte membrane 3 and firmly connecting the plurality of power generation units 1 to each other. A planar planar array structure 11A is produced.

  Next, as shown in FIG. 1 (e), a planar tank 11A is sandwiched between a cathode plate and an anode plate made of a current collector 6 or 7 and an insulating layer 8, and methanol 9 is stored as an aqueous solution, for example. 10 is provided to complete the fuel cell 12. Here, the current collectors 6 and 7 can be made of a punched metal such as gold-plated SUS or mesh, and the insulating layer 8 can have strength and heat resistance such as PPS (polyphenylene sulfide) or PEEK (polyetheretherketone). It is possible to use hard plastics and ceramics excellent in the above. When actually used as the fuel cell 12, the power generation units 1 may be connected in series, but the connection state is not shown here.

  In the present embodiment, the state in which the power generation units 1 are arranged at six locations is illustrated, but it goes without saying that the number and arrangement pattern may be changed as necessary.

  As the material of the above-described sheets 2a and 2b, for example, a thermoplastic resin such as polyethylene, polypropylene, polystyrene, polyvinyl acetate, and polyester such as PET can be used.

  These sheets 2 a and 2 b are modified with at least one selected from the group consisting of acids, acid anhydrides, acid esters, metallocenes and hydroxyl groups (or esterified products thereof) on the adhesive surface with the electrolyte membrane 3. Adhesiveness will be good if what was (surface-treated) is used.

  Sheets 2a and 2b have good adhesion when they have a hydroxyl group or a basic substituent such as imidazole, pyridine or amine that can be bonded to the sulfonic acid group of the electrolyte by electrostatic interaction.

  FIG. 3 shows an example of a mechanism by which the sheets 2 a and 2 b adhere to the electrolyte membrane 3.

  For example, the sheet 2a made of a vinyl-based thermoplastic resin copolymerized with a hydroxyl group is brought into contact with the solid electrolyte membrane 3 having a sulfonic acid group, and heat is applied, whereby the hydroxyl groups of the sheets 2a and 2b are converted into the electrolyte membrane 3. It is presumed that the two groups react strongly with each other by an ester bond. The same applies to the adhesion of sheets 2c, 2d, and 2e described later.

  Next, with respect to the table shown in FIG. 4, as a material for the above-described sheets (or films) 2 a and 2 b, for example, adhesion when using various types of polyvinyl alcohol (Poval: PVA) resins having good oxygen barrier properties. The characteristics and the like will be described. This table shows the low-temperature adhesiveness of each resin, the adhesiveness when immersed in water, MeOH (methanol) and when immersed in hot water, and the dimensional stability at the time of film peeling. Very good adhesion, ○ means peeling of the adhesive surface: good adhesion, Δ means peeling of the adhesive surface: insufficient adhesion, and x means non-adhesion or peeling: poor adhesion.

  According to this table, PVA resin sheet (30 μm thickness), PVA resin sheet (50 μm thickness), PVA resin sheet (40 μm thickness) (all of which are manufactured by Kuraray Co., Ltd.) have good low-temperature adhesiveness, In dipping, MeOH dipping and hot water dipping, the adhesive strength is sufficient to cause film breakage, but dimensional stability tends to be insufficient due to moisture absorption.

  On the other hand, the ethylene-polyvinyl alcohol copolymer resin sheet (ethylene content of about 30 mol% or about 45 mol%) (both manufactured by Kuraray Co., Ltd.) has very good low-temperature adhesion, and is also immersed in water and MeOH. Adhesive strength is sufficient in immersion and hot water immersion, and dimensional stability is also good.

  In addition, Idemitsu LL film (made by Idemitsu Kosan Co., Ltd.) has good adhesive strength at low temperature adhesion and very good dimensional stability. However, the adhesive strength decreases in water immersion, and in MeOH immersion and hot water immersion. Adhesive strength is poor, and it becomes non-adhered or peeled.

  From these results, it can be said that the PVA adhesive is a material having a generally high adhesive strength as a whole. However, Poval has poor dimensional stability due to moisture absorption, whereas Eval resin or a composite film of Eval resin (for example, a composite film with polypropylene film) has low-temperature adhesion, water immersion, MeOH immersion and hot water immersion, Further, both of the dimensional stability are excellent, and it can be said that it is preferable as the material of the sheets 2a and 2b.

  The above-described PVA-based resin, polyacrylonitrile, and the like have a relatively low gas permeation rate in the resin film and have high gas sealing properties, so that they are excellent as materials for the sheets 2a and 2b.

  As described above, by using a resin having high adhesion to the electrolyte membrane 3 for the sheets 2a and 2b, the adhesion between the electrolyte membrane 3 and the adhesive layer 2 by the sheets a and 2b is improved, and a gap is formed between the two even by moisture absorption. Is less likely to occur, gas leakage is drastically reduced, and gas sealability can be improved.

  As described above, according to the present embodiment, the exposed portions 3a of the electrolyte membrane 3 projecting from the positive electrode 4 and the negative electrode 5 between the plurality of power generation units 1 adjacent to each other are the thermoplastic resin sheets 2a and 2b. Embedded in a gas-barrier adhesive layer 2 made of a thermocompression bonding body, and a plurality of power generation units 1 are connected, so that the gas sealing property on the adhesive surface between the exposed exposed portion 3a of the electrolyte membrane 3 and the adhesive layer 2 (In other words, the fuel and oxygen permeation prevention properties such as methanol are improved), and at the same time, there is no movement of undesired ions between the adjacent electrolyte membranes 3, so that the reliability as a device is high and the fuel efficiency is improved. It is possible to obtain a planar array structure 11A that realizes improvement in power generation efficiency.

  In addition, by connecting the exposed portions 3a of the facing electrolyte membrane 3 with the adhesive layer 2, a high-power and thin structure in which a plurality of power generation portions 1 are arranged at high density on the same surface along the surface direction can be easily achieved. Can be produced.

Second Embodiment FIGS. 5 to 6 show a second embodiment of the present invention.

  In the fuel cell according to the present embodiment, as shown in FIG. 5, the thermoplastic resin sheets 2c, 2d and 2e are laminated to form the adhesive layer 2 by thermocompression bonding, and the adjacent power generation unit 1A and 1B is arranged with a slight shift in the thickness direction, and the exposed portions 3a of the electrolyte membranes 3 of the respective power generation units 1A and 1B are arranged close to each other so as to partially overlap in the thickness direction. Except for this, it is the same as the first embodiment described above.

  The planar array structure 11B according to the present embodiment will be described based on the manufacturing process shown in the cross-sectional view of FIG. 5 and the perspective view of FIG.

  First, as shown to Fig.5 (a), the opening parts 13c and 13d for accommodating each electric power generation part 1A and 1B, respectively are formed in the thermoplastic resin sheet 2c.

  Next, as shown in FIG. 5B, the negative electrode 5 of the power generation unit (MEA) 1A composed of the electrolyte membrane 3, the positive electrode 4, and the negative electrode 5 is fitted into the opening 13c among these openings, and the electrolyte membrane 3 The exposed portion 3a is in close contact with the sheet 2c.

  Next, as shown in FIGS. 5C and 6, a thermoplastic resin sheet 2d having an opening 13e and an opening 13f for accommodating each power generation unit 1B is disposed, and power generation is performed in the opening 13e. The negative electrode 5 of the part 1B is fitted, the exposed part 3a of the electrolyte membrane 3 is placed, and the positive electrode 4 of the power generation part 1A is fitted into the opening 13f.

  Next, as shown in FIG. 5D, heat having an opening 13g and an opening 13h into which the positive electrode 4 of the power generation unit 1A and the positive electrode 4 of the power generation unit 1B and the exposed part 3a of the electrolyte membrane 3 are fitted, respectively. The plastic resin sheet 2e is covered.

  Next, as shown in FIG. 56 (e), only the sheets 2c, 2d, and 2e are heated and thermocompression-bonded to form an adhesive layer 2 having flat surfaces. As a result, the planar array structure 11 </ b> B in which the adhesive layer 2 is embedded in the exposed portion 3 a of the electrolyte membrane 3 and bonded to each other is manufactured.

  Finally, similarly to the structure shown in FIG. 1E, the planar array structure 11B is provided with a current collector, an insulating layer, and a methanol tank containing methanol to complete a fuel cell.

  According to the present embodiment, the adjacent power generation units 1A and 1B are arranged slightly shifted in the thickness direction, and the exposed portion 3a of the electrolyte membrane 3 of each power generation unit 1A and 1B is partially in the thickness direction. Since it is embedded in the adhesive layer 2 so as to overlap, the overall size of the planar array structure 11B can be reduced, and the coupling strength between the exposed portions 3a of the electrolyte membrane 2 that partially overlaps is also improved. It becomes larger and the strength of the planar array structure itself is improved.

  In FIG. 5 (e), the adjacent electrodes are illustrated so that their heights are different from each other, but in actuality, the sealing portion is heated and sealed, so that the electrolyte membrane is bent and the thickness thereof is corrected. As a result, the adjacent electrodes become flat.

  In addition, in the present embodiment, the same operations and effects as described in the first embodiment described above can be obtained.

  Examples of the present invention will be specifically described below together with comparative examples.

Example 1
In order to produce the planar array structure 11A shown in FIG. 1D, first, catalyst ink was applied to carbon paper on the electrolyte membrane 3 (size: 14 mm × 14 mm, thickness 25 μm). Gas diffusion electrodes (positive electrode 4 and negative electrode 5) (each size: 10 mm × 10 mm) were joined at 130 ° C. for 15 minutes at a pressure of 0.5 kN to produce each power generation unit (MEA) 1.

  On the other hand, polyethylene-polyvinyl alcohol copolymer resin sheet (thickness: 30 μm) is obtained by cutting each opening 13a having the same size as each of the above gas diffusion electrodes: 10 mm × 10 mm in series (for example, 6 locations) at intervals of 5 mm. Formed in 2a. Each electrode 5 was fitted into each of these openings, and further sandwiched between polyethylene-polyvinyl alcohol copolymer resin sheets 2b of the same size.

  Next, while keeping the electrode surfaces of the electrodes 4 and 5 horizontal, only the portions of the polyethylene-polyvinyl alcohol copolymer resin sheets 2a and 2b were thermocompression bonded at 150 ° C. for 1 minute at a pressure of 1 kN, and the sheets 2a and 2b An adhesive layer (seal) 2 was formed by integrating 2b. Thereby, in the planar arrangement as shown in FIG. 1 (d) and FIG. 2, a planar array structure in which the exposed portion 3a of the electrolyte membrane 3 of each MEA 1 is embedded in the adhesive layer 2 and proton insulation is provided between the MEAs 1. 11A was obtained.

  In Example 1, the polyethylene-polyvinyl alcohol copolymer resin sheet 2 with the electrolyte membrane 3 sealed is a set of electrodes 4 and 5 arranged at six locations as a whole, and the overall size is 50 mm × 35 mm. It was.

Example 2
In order to produce the planar array structure 11B shown in FIG. 5 (e), first, the openings 4c and 13d having the same size as each electrode 4 and 5: 10 mm × 10 mm are arranged in series at intervals of 3 mm (for example, 6 Part) A polyethylene-polyvinyl alcohol copolymer resin sheet (thickness: 30 μm) 2c was formed by cutting. Among these openings, the electrode 5 of the power generation section 1A was fitted into the opening 13c.

  Next, the electrode 5 of the power generation unit 1B was fitted into the opening 13e formed by cutting the modified polyethylene-polyvinyl alcohol copolymer resin sheet 2d of the same size, and this was further fitted into the opening 13d of the sheet 2c. Thereafter, each electrode was fitted into the openings 13g and 13h formed by cutting the polyethylene-polyvinyl alcohol copolymer resin sheet 2e of the same size.

  Next, while keeping the electrode surfaces of the electrodes 4 and 5 horizontal, only the portions of the polyethylene-polyvinyl alcohol copolymer resin sheets 2c, 2d, and 2e are thermocompression bonded at 150 ° C. for 1 minute at a pressure of 1 kN, An adhesive layer (seal) 2 was formed by integrating 2c, 2d and 2e. Thereby, in the planar arrangement as shown in FIGS. 5 (e) and 6, the exposed portion 3a of the electrolyte membrane 3 of each MEA 1A, 1B is embedded in the adhesive layer 2, and the planar arrangement in which the MEAs are proton-insulated A structure 11B was obtained.

  In Example 2, the polyethylene-polyvinyl alcohol copolymer resin sheet 2 with the electrolyte membrane 3 sealed is a set of electrodes 4 and 5 arranged at six locations as a whole, and the overall size is 42 mm × 29 mm. It was.

Example 3
After each MEA was produced in the same manner as described in Example 1, the openings equivalent to the size of each electrode 4 and 5: 10 mm × 10 mm were cut in series at intervals of 3 mm to obtain a polyethylene-polyvinyl alcohol copolymer resin film and polypropylene. The film was formed into a multilayer film (thickness: 50 μm). Each electrode was fitted into these openings, and further sandwiched between multilayer films of polyethylene-polyvinyl alcohol copolymer resin film and polypropylene film of the same size. Then, as described in Example 2, the films were thermocompression bonded to produce a planar array structure having an overall size of 42 mm × 29 mm.

Comparative Example 1
The power generation unit (MEA) has an electrolyte membrane size of 16 mm × 16 mm, and a power generation unit (MEA) in which the thickness of the electrolyte membrane sandwiched between the resin sheets is 3 mm is manufactured in order to improve sealing performance. Openings of 10 mm × 10 mm equivalent to each electrode size are formed in a series of Teflon (registered trademark) gaskets (thickness: 400 μm) at intervals of 7 mm, and each electrode is fitted into these openings. A planar array structure having a total size of 58 mm × 41 mm was prepared by sandwiching with a Teflon (registered trademark) gasket. However, in this cell, since it is only sealed with a gasket, each power generation part is easily displaced, and workability is poor.

  Each planar array structure produced in Examples 1 to 3 and Comparative Example 1 described above is incorporated into a structure as shown in FIG. 1 (e) including a current collector, an insulating layer, and a methanol tank containing methanol, Each power generation unit was connected in series. At this time, since each power generation part of Examples 1 to 3 had an integrated (connected) structure, it was very easy to incorporate. Further, since the electrolyte membrane of each MEA is sealed inside, it is desirable to seal the peripheral portion of the planar array structure with emphasis, but here the peripheral portion is simply sealed with silicon rubber. In Comparative Example 1, since the Teflon (registered trademark) gasket also serves as a peripheral seal as it is, each power generation unit was carefully incorporated so as not to be displaced.

  And performance evaluation was performed about the fuel cell using the planar array structure of Examples 1-3 and the comparative example 1. FIG.

  Specifically, the open circuit voltage (OCV: open circuit voltage) and the temperature of each fuel cell after 1 hour when an 80 wt% aqueous methanol solution was used as the fuel were measured. The results are shown in Table 1 below. Moreover, the temperature and power generation time of each fuel cell when generating power with a constant power of 200 mW using 3 cc of fuel were measured. The results are shown in Table 2 below.

  As is clear from the results shown in Table 1, in each fuel cell of Examples 1 to 3, an open circuit voltage (OCV) of about 3 V was obtained, and the proton insulating portion between the electrolyte membranes was normally formed by the adhesive layer (resin). It was confirmed that it was produced.

  In addition, although heat generation in the open circuit state is considered to be an indication of poor sealing, it is about 40 ° C. in each fuel cell of Examples 1 to 3, and 53 ° C. in the fuel cell of Comparative Example 1. It was. Since this is also a temperature lower than the temperature in the normal sealing method (Comparative Example 1), it was clear that the sealing performance was also good.

  Further, as is apparent from the results shown in Table 2, the temperature after 1 hour of power generation is about 45 ° C. in each of the fuel cells of Examples 1 to 3, and 57 ° C. in the fuel cell of Comparative Example 1. Met. It was confirmed that the temperature after 1 hour of power generation was low.

  In addition, the power generation time is about 6 hours in Examples 1 to 3, which is longer than 4 hours of Comparative Example 1, and since the sealing performance is high even during power generation, fuel consumption due to fuel leakage is reduced. Power generation time has also been extended.

  As mentioned above, although this invention was demonstrated based on embodiment and an Example, this invention is not limited to these examples at all, and it cannot be overemphasized that it can change suitably in the range which does not deviate from the main point of invention. .

  For example, a thermoplastic resin other than those described above may be used as the material for the above-described resin sheet or adhesive layer, and further the peripheral sealing material, or thermosetting such as epoxy resin, urea resin, melamine resin, and urethane resin. Resin, silicon rubber, rubber-like liquid sealing material, and the like can be used.

  In addition, the above-described method for forming the adhesive layer is not limited to thermocompression bonding after the sheets are laminated, and may be a potting method for an adhesive material, a coating method, or an injection method using a mold.

  Moreover, the arrangement | positioning of each electric power generation part may be laminated | stacked not only on the surface direction but the thickness direction of the electric power generation part as needed. Each power generation unit is preferably connected in series from the viewpoint of high output, but may be connected in parallel or may be mixed in series and parallel.

  In addition, methanol gas may be directly supplied as fuel. In this case, an appropriate amount of water may be added at the start of battery operation to promote the reaction on the negative electrode side. The fuel cell may be a fuel cell using a fuel other than the methanol type, such as a hydrogen type fuel cell.

  Moreover, it can also be set as the fuel cell of the structure which integrated the above-mentioned 1st Embodiment and 2nd Embodiment.

  The electrochemical device of the present invention can be applied to a fuel cell or the like that can be easily manufactured with high power generation efficiency.

It is sectional drawing which shows the manufacturing process of the fuel cell by the 1st Embodiment of this invention sequentially. It is a perspective view which shows the same manufacturing process of a fuel cell. It is a chemical formula showing the adhesion mechanism. It is a table | surface which shows the adhesive performance of various resin similarly. It is sectional drawing which shows the manufacturing process of the fuel cell by the 2nd Embodiment of this invention sequentially. It is a perspective view which shows the same manufacturing process of a fuel cell. The schematic sectional drawing of the fuel cell by a prior art example. It is sectional drawing of another fuel cell same as the above.

Explanation of symbols

1A, 1B ... power generation part (MEA), 2 ... adhesive layer (seal),
2a, 2b, 2c, 2d, 2e ... thermoplastic resin sheet, 3 ... electrolyte membrane,
4 ... Positive electrode (cathode), 5 ... Negative electrode (anode), 6, 7 ... Current collector, 8 ... Insulating layer,
9 ... methanol, 10 ... methanol tank, 11A, 11B ... planar array structure,
12. Fuel cell,
13a, 13b, 13c, 13d, 13e, 13f, 13g, 13h ... opening

Claims (8)

  In an electrochemical device in which a plurality of membrane / electrode assemblies including an electrolyte membrane and a first electrode and a second electrode sandwiching the electrolyte membrane are arranged along a plane direction at a predetermined interval The exposed portion of the electrolyte membrane protruding from the first electrode and the second electrode between a plurality of adjacent membrane / electrode assemblies is embedded in a gas barrier adhesive layer, thereby An electrochemical device characterized in that membrane-electrode assemblies are linked.   The electrochemical device according to claim 1, wherein the plurality of membrane / electrode assemblies are arranged on the same surface, and both surfaces of the adhesive layer are flat.   Both surfaces of the adhesive layer in a state in which the exposed portions of the electrolyte membrane protruding opposite to the first electrode and the second electrode of the plurality of membrane / electrode assemblies are arranged at positions overlapping with the adhesive layer. The electrochemical device according to claim 1, wherein is flat.   The electrochemical device according to claim 1, wherein the adhesive layer is formed by bonding at least two layers of film-like resin.   The electrochemical device according to claim 4, wherein the film-like resin is made of a thermoplastic resin, and the exposed portion of the electrolyte membrane and the adhesive layer are bonded by heating the film-like resin.   The film-like resin is modified with at least one selected from the group consisting of an acid, an acid anhydride, an acid ester, a metallocene, and a hydroxyl group (or esterified product thereof) on the adhesive surface with the exposed portion of the electrolyte membrane. The electrochemical device according to claim 4.   5. The electrochemical device according to claim 4, wherein the film-like resin is obtained by polymerizing a hydroxyl group that can be bonded to an electrolyte sulfonic acid group by interaction or a molecule having a basic substituent such as imidazole, pyridine, or amine. .   The electrochemical device according to claim 1 configured as a fuel cell.

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