JP2007265925A - Solid electrolyte film and its manufacturing method, manufacturing facility, as well as electrode membrane assembly, and fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To mass-produce a solid electrolyte film of fixed quality and high proton conductivity by forming solid electrolyte into a film continuously. <P>SOLUTION: A dope 24 that has cation species and contains a polymer which is a precursor of a solid electrolyte is flow-cast on a traveling flow-casting belt 94 so that a flow-casting membrane is formed. In a tank 101, flow-casting membrane 61 is peeled off from the flow-casting belt 94, and formed into a gel-state precursor film 65. The precursor film 65 is dried with a tenter 83, then in succession soaked into a bathtub 84 in which solution containing acid is reserved, so that the cation species is substituted by hydrogen atom and protonated, thus a solid electrolyte film 70 is obtained. The solid electrolyte film 70 is sent into a water vessel 85 to have an excessive acid removed, and dried in a drying room 86. According to this method, the process from formation of the flow-casting membrane to the acid treatment and the film manufacturing can be carried out continuously, and the solid electrolyte film 70 with high proton conductivity is enabled to be mass-produced continuously. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a solid electrolyte film, a method for producing the same, a production facility, an electrode membrane composite using the solid electrolyte film, and a fuel cell.

  In recent years, lithium ion batteries and fuel cells that can be used as power sources for portable devices and the like have attracted attention, and active research is also being conducted on solid electrolytes that are mainstream members. The solid electrolyte is, for example, a lithium ion conductive material or a proton conductive material. When used in a fuel cell or the like, the solid electrolyte is usually a film-like solid electrolyte, that is, a solid electrolyte film.

  Known solid electrolytes include inorganic compounds such as potassium hydroxide and phosphoric acid, polymers, and the like. In general, a solid electrolyte film made of an inorganic compound has a high operating temperature but a high power generation output. On the other hand, a polymer solid electrolyte film made of a polymer has characteristics such that it can start operation even at the same temperature as the air temperature, although its power generation output is low. Therefore, recently, a polymer solid electrolyte film has attracted attention as a solid electrolyte film for home use, on-vehicle use or portable use.

  In general, a polymer solid electrolyte film is produced by a solution casting method. In the solution casting method, after preparing a dope containing a polymer and an organic solvent, the dope is cast on a support to form a cast film, and then dried to form a film. How to get. Until now, a protonated polymer, that is, a protonated polymer has been used in preparing a dope for the purpose of producing a polymer solid electrolyte film having high proton conductivity. However, since protonated polymers are chemically unstable, they are susceptible to temperature and humidity during film formation. Therefore, in the method of forming a film from a protonated polymer as described above, it is difficult to stably and continuously manufacture a polymer solid electrolyte film having high proton conductivity.

  Up to now, as a method for producing a polymer solid electrolyte film having excellent properties such as proton conductivity and mechanical strength, for example, a polymer form by a solution casting method using a dope containing an acidic group-containing polymer. A gel film is formed from a dope containing an acidic group-containing polymer by a method for producing a solid electrolyte film (see, for example, Patent Document 1) or a solution casting method, and then washed with water and further dried to form a polymer. A method for forming a solid electrolyte film has been proposed (see, for example, Patent Document 2). In addition, after the dope is formed into a film by a solution casting method, the polymer solid is excellent in thermal stability by being immersed in an aqueous organic compound solution having a boiling point of 100 ° C. or higher after being made water-soluble. A method capable of producing an electrolyte film has also been proposed (see, for example, Patent Document 3).

  In addition, after forming a dope containing an ion conductive component into a film form by a solution casting method, this is immersed in a solvent to remove a water-soluble compound, and then dried, so that the polymer form has high proton conductivity. A method capable of producing a solid electrolyte film has been proposed (see, for example, Patent Document 4). Furthermore, Patent Documents 5 to 7 describe a method for producing a polymer solid electrolyte film from a dope containing a predetermined proarene by a solution casting method.

Patent Document 8 describes a method in which a dope containing a predetermined sulfonic acid group-containing polymer is made into a film and then acid-treated, and Patent Document 9 describes ionicity by a solution casting method. A method of acid treating a film formed from a dope comprising a polymer having groups is described.
JP-A-2005-232240 JP 2005-235466 A Japanese Patent Laid-Open No. 2005-248128 JP 2005-310443 A JP 2004-079378 A JP-A-2005-146018 JP 2005-239833 A JP 2005-268144 A JP 2005-268145 A

  In each of Patent Documents 8 and 9, acid treatment is performed by immersing a film formed from a dope containing a polymer having a sulfonic acid group or an ionic group, which is a cationic species, in an acid. Thereby, the cationic species can be replaced with protons, and therefore, a polymer solid electrolyte film having high proton conductivity can be obtained. However, in each of the methods described in Patent Documents 8 and 9, the film forming step and the acid treatment step are performed off-line, that is, both steps are not continuous. Therefore, it is possible to continuously perform a series of steps from casting the dope to producing a polymer solid electrolyte film having high proton conductivity, and mass production of the solid electrolyte film as described above. difficult.

  Regardless of Patent Documents 8 and 9, the methods proposed in Patent Documents 1 to 7 are all small-scale manufacturing methods, and cannot be said to be methods conscious of mass production. Furthermore, Patent Documents 5 to 7 describe that a polymer solid electrolyte film can be produced, but there is no description of a specific method.

  An object of the present invention is to provide a production method capable of continuously and mass-producing a solid electrolyte film having a high proton conductivity. Another object of the present invention is to provide a production method in which fluctuations in proton conductivity due to the influence of temperature and humidity are suppressed even if polymer solid electrolyte films are produced continuously.

  Therefore, in the method for producing a solid electrolyte film according to the present invention, a dope containing an organic solvent and a polymer having a cationic species and a solid electrolyte precursor is cast from a casting die on a traveling support. A first step of continuously forming a cast film, a second step of peeling the cast film from a support to form a precursor film made of a precursor, and a precursor film in an acid solution as a proton donor. A third step of making a solid electrolyte film made of a solid electrolyte in which the cation species are replaced with hydrogen atoms, a fourth step of washing the solid electrolyte film, and a fifth step of drying the solid electrolyte film. And the first process to the fifth process are continuous.

  The contact is preferably at least one of immersion of the precursor film in the solution, spraying of the solution to the precursor film, and application of the solution to the precursor film.

  The solid electrolyte film is preferably washed by bringing it into contact with water.

  The acid is preferably a compound having a formula weight of 40 to 1000 when ionized when ionized. Moreover, it is preferable that the temperature of a solution shall be 30 degreeC or more and 120 degrees C or less. Furthermore, it is preferable that the temperature of water shall be 30 degreeC or more and 120 degrees C or less.

（ただし、Ｘはカチオン種であり、ＹはＳＯ_２ であり、Ｚは化４の（Ｉ）または（ＩＩ）に示す構造であり、ｎとｍとは０．１≦ｎ／（ｍ＋ｎ）≦０．５を満たす。）

The polymer is preferably a hydrocarbon polymer. The hydrocarbon polymer is preferably an aromatic polymer. And it is preferable that an aromatic polymer is a copolymer which consists of each structural unit shown by General formula (I)-(III) of Chemical formula 3.

(However, X is a cationic species, Y is SO ₂ , Z is the structure shown in Chemical Formula (I) or (II), and n and m are 0.1 ≦ n / (m + n) ≦ 0.5 is satisfied.)

  It is preferable to bring a liquid having a boiling point lower than that of the organic solvent and a poor polymer solvent into contact with the cast film.

  The production facility for a solid electrolyte film of the present invention has a flow having a traveling support and a casting die for casting a dope containing a polymer that has an organic solvent and a cationic species and is a precursor of the solid electrolyte to the support. A film forming apparatus, a conveying apparatus that conveys a precursor film that is a cast film peeled off from a support, and a precursor film that is conveyed by the conveying apparatus are brought into contact with an acid solution that is a proton donor. An acid contact device that forms a solid electrolyte film made of a solid electrolyte in which a cation species is replaced with a hydrogen atom, a cleaning device that cleans the solid electrolyte film and removes an acid that has only been involved in the substitution, and is washed. And a drying device for drying the solid electrolyte film.

  The solid electrolyte film of the present invention is manufactured by any one of the above manufacturing methods.

  The electrode membrane composite of the present invention is provided with the above solid electrolyte film and an anode electrode that is provided in close contact with one surface of the solid electrolyte film and generates protons from a hydrogen-containing substance supplied from the outside. And a cathode electrode that is provided in close contact with the other surface of the solid electrolyte film and synthesizes water composed of protons that have passed through the solid electrolyte film and gas supplied from the outside.

  Furthermore, the present invention comprises the above electrode membrane composite, and a current collector provided in contact with the electrode of the electrode membrane composite and for transferring electrons to and from the anode and cathode electrodes. The fuel cell includes the characteristic fuel cell.

  In the present invention, after casting a dope prepared by mixing a polymer containing a cationic species serving as a precursor of a solid electrolyte and an organic solvent to form a cast film, this is converted into a gel. As a precursor film, this film was then acid-treated, so that the protonation could be reduced under the influence of temperature and humidity during the production process, and the solid electrolyte with high proton conductivity Films can be manufactured continuously. In addition, the electrode membrane assembly using this solid electrolyte film expresses an excellent electromotive force when used in a fuel cell.

  Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the embodiments described here. First, the solid electrolyte film according to the present invention will be described, and then the manufacturing method thereof will be described. In the following description, the solid electrolyte film may be simply referred to as a film.

In the present invention, when preparing the dope, a polymer having a cationic species and being a precursor of a solid electrolyte is used. This polymer is preferably a hydrocarbon polymer, and among them, the hydrocarbon polymer is preferably an aromatic polymer. The aromatic polymer is preferably a copolymer composed of structural units represented by the general formulas (I) to (III) of Chemical Formula 3. However, X is a cationic species, Y is SO ₂ , Z is a structure shown in Chemical Formula (I) or (II), and n and m are 0.1 ≦ n / (m + n) ≦ 0 .5 is satisfied.

  In particular, the film of the substance shown in Chemical Formula 3 achieves both the hygroscopic expansion coefficient and the proton conductivity. When n / (m + n) <0.1, there are too few sulfonic acid groups, and proton conduction paths, so-called proton channels may not be sufficiently formed. Therefore, the obtained film may not exhibit proton conductivity sufficient for practical use. In addition, when n / (m + n)> 0.5, the water absorbability of the film becomes high, so that the expansion coefficient due to water absorption, that is, the water absorption expansion coefficient increases, and the film is likely to deteriorate.

  As described above, in the present invention, after preparing a dope containing a polymer (hereinafter referred to as a precursor) in which X in Chemical Formula 3 is a cationic species other than proton, this is cast on a support to contain a precursor. A solid electrolyte film having a high proton conductivity by peeling off as a film (hereinafter referred to as a precursor film) and performing an acid treatment in which the precursor film is brought into contact with an acid, so that X is proton-substituted to become H. Can be manufactured. The acid treatment will be described later in detail.

  In the present invention, the cation species means an atom or an atomic group that generates a cation when ionized. This cationic species need not be monovalent. However, in the present invention, cations other than protons, for example, alkali metal cations, alkaline earth metal cations, and ammonium cations are preferable, and calcium ions, barium ions, quaternary ammonium ions, lithium ions, sodium ions, and potassium ions are generated. Those are preferred. And the proton conductivity of a solid electrolyte film becomes so high that the ratio substituted by H among the cationic species of X is large. In the present invention, proton conductivity is used as a proton conduction index in the solid electrolyte film, and the higher the value, the better the solid electrolyte film.

A solid electrolyte produced by proton substitution of a polymer that is a precursor of the solid electrolyte by an acid treatment described later will be described. This solid electrolyte preferably has the following performances. The ionic conductivity is preferably 0.005 S / cm or more, and more preferably 0.01 S / cm or more, for example, at 25 ° C. and a relative humidity of 70%. Further, the ionic conductivity after being immersed in a 50% aqueous methanol solution at 18 ° C. for one day is preferably 0.003 S / cm or more, more preferably 0.008 S / cm or more, and particularly with respect to before immersion. What the fall rate of the ionic conductivity after immersion is 20% or less is preferable. The methanol diffusion coefficient is preferably 4 × 10 ⁻⁷ cm ² / s or less, and particularly preferably 2 × 10 ⁻⁷ cm ² / s or less.

  As for the strength of the solid electrolyte, one having an elastic modulus of 10 MPa or more is preferable, and one having 20 MPa or more is particularly preferable. The method for measuring the elastic modulus is described in detail in paragraph [0138] of JP-A-2005-104148, and the above value of the elastic modulus is a value obtained by a tensile tester manufactured by Toyo Baldwin. Therefore, when obtaining the elastic modulus using another test method or tester, it is preferable to obtain the correlation with the value obtained by the test method or tester in advance.

  As for the durability of the solid electrolyte, it is preferable that each change rate of weight, ion exchange capacity, and methanol diffusion coefficient is 20% or less before and after a time-lapse test immersed in 50% methanol at a constant temperature. 15 % Or less is particularly preferred. Further, before and after the time-lapse test in hydrogen peroxide, the rate of change in weight, ion exchange capacity, and methanol diffusion coefficient is preferably 20% or less, and particularly preferably 10% or less. Further, in 50% methanol, the volume swelling rate at a constant temperature is preferably 10% or less, particularly preferably 5% or less.

  Furthermore, a solid electrolyte having a stable water absorption rate and moisture content is preferable. And it is preferable that it is so small that solubility is substantially negligible with respect to alcohol, water, and the mixed solvent of alcohol and water. Further, it is preferable that the weight loss and the shape change when immersed in the liquid are small enough to be substantially ignored.

  The ionic conduction performance of the solid electrolyte film is expressed by a so-called index which is a ratio between the ionic conductivity and the methanol permeability coefficient. And it can be said that the larger the index in a certain direction, the higher the ion conduction performance in that direction. In the thickness direction of the solid electrolyte film, the ionic conductivity is proportional to the thickness, and the methanol permeability coefficient is inversely proportional to the thickness. Therefore, the ionic conductivity of the solid electrolyte film can be controlled by changing the thickness. In a solid electrolyte film used for a fuel cell, an anode electrode is provided on one side and a cathode electrode is provided on the other side. Therefore, the index in the thickness direction of the solid electrolyte film is larger than the index in the other direction. Is preferred. The thickness of the solid electrolyte film is preferably 10 to 300 μm. For example, in the case of a solid electrolyte having both high ionic conductivity and methanol diffusion coefficient, it is particularly preferable to produce a film having a thickness of 50 to 200 μm, and a solid having both low ionic conductivity and methanol diffusion coefficient. In the case of an electrolyte, it is particularly preferable to produce a film so that the thickness is 20 to 100 μm.

  The heat resistant temperature is preferably 200 ° C. or higher, more preferably 250 ° C. or higher, and particularly preferably 300 ° C. or higher. The heat-resistant temperature here means a temperature that reaches 5% weight loss when heated at a rate of 1 ° C./min. Note that this weight reduction is calculated excluding the amount of evaporation such as moisture.

Furthermore, when a solid electrolyte is used as a film for a fuel cell, the solid electrolyte is preferably a solid electrolyte having a maximum output density of 10 mW / cm ² or more.

  By using the above solid electrolyte, it is possible to produce a solution (dope) suitable for production of a film, and it is possible to produce a solid electrolyte film suitable as a fuel cell. The solution suitable for the production of the film is, for example, a solution having a relatively low viscosity and easily removing foreign matters in advance by filtration.

  The organic solvent used for the dope (sometimes simply referred to as a solvent) may be any organic compound that can dissolve the polymer used for preparing the dope. Examples include aromatic hydrocarbons (eg, benzene, toluene, etc.), halogenated hydrocarbons (eg, dichloromethane, chlorobenzene, etc.), alcohols (eg, methanol, ethanol, n-propanol, n-butanol, diethylene glycol, etc.), Ketones (eg, acetone, methyl ethyl ketone, etc.), esters (eg, methyl acetate, ethyl acetate, propyl acetate, etc.), ethers (eg, tetrahydrofuran, methyl cellosolve, etc.), and nitrogen-containing compounds (N-methylpyrrolidone (NMP)) N, N-dimethylformamide (DMF), N, N′-dimethylacetamide (DMAc), etc.), dimethyl sulfoxide (DMSO) and the like.

  The organic solvent for preparing the dope may be a mixture in which a plurality of substances are mixed. When the solvent is a mixture, it is preferable to use a mixture of a good solvent and a poor solvent for the polymer. Whether the polymer is a good solvent or a poor solvent is determined based on the presence or absence of insoluble matter that is confirmed when the solvent and the polymer are mixed so that the polymer is 5% by weight of the total weight. be able to. That is, if the polymer is dissolved, the solvent is a good solvent, while if the polymer remains undissolved, the solvent is a poor solvent. A good solvent for a polymer has a relatively high boiling point among compounds generally used as a solvent, while a poor solvent has a relatively low boiling point among compounds generally used as a solvent. Therefore, by mixing the poor solvent with the good solvent, the efficiency and effect of removing the solvent in the film production process can be enhanced, and in particular, the drying efficiency of the cast film can be greatly improved.

  In a mixture of a good solvent and a poor solvent, the weight ratio of the poor solvent is preferably as large as possible, specifically 10% or more and less than 100%. More preferably, (weight of good solvent) :( weight of poor solvent) is 90:10 to 10:90. Thereby, since the ratio of the low boiling-point component in the weight of all the solvents becomes large, the drying efficiency and the drying effect in the manufacturing process of a solid electrolyte film can be improved more.

  As the good solvent component, DMF, DMAc, DMSO, and NMP are preferable. Among them, DMSO is particularly preferable in terms of safety and relatively low boiling point. As the poor solvent component, a so-called lower alcohol having 1 to 5 carbon atoms, methyl acetate, and acetone are preferable. Among them, a lower alcohol having 1 to 3 carbon atoms is more preferable, and when DMSO is used as a good solvent. Methyl alcohol is particularly preferred from the viewpoint of the most excellent compatibility with it.

  When forming a solid electrolyte film from a dope prepared by mixing a polymer and a solvent as described above, an additive can be added to the dope in order to improve the properties of various films. Examples of the additive include an antioxidant, fibers, fine particles, a water absorbing agent, a plasticizer, and a compatibilizer. The addition rate of these additives is preferably in the range of 1% by weight to 30% by weight when the total solid content in the dope is 100% by weight. However, the addition rate and the type of substance do not adversely affect the ionic conductivity. The additive will be specifically described below.

  Antioxidants include (hindered) phenolic, monovalent or divalent sulfur, trivalent phosphorus, benzophenone, benzotriazole, hindered amine, cyanoacrylate, salicylate, oxalic acid anilide These compounds are listed as preferred examples. Specific examples thereof include compounds described in JP-A-8-53614, JP-A-10-101873, JP-A-11-114430, and JP-A-2003-151346.

  Preferred examples of the fibers include perfluorocarbon fibers, cellulose fibers, glass fibers, polyethylene fibers, and the like, and specifically, JP-A-10-31815, JP-A-2000-231938, JP-A-2001-307545. And fibers described in JP-A Nos. 2003-317748, 2004-63430, and 2004-107461.

  Examples of the fine particles include titanium oxide, zirconium oxide, and the like. Specific examples include various fine particles described in JP-A Nos. 2003-178777 and 2004-217931.

  Water-absorbing agents, that is, hydrophilic substances include cross-linked polyacrylate, starch-acrylate, poval, polyacrylonitrile, carboxymethylcellulose, polyvinylpyrrolidone, polyglycol dialkyl ether, polyglycol dialkyl ester, synthetic zeolite, titania gel, zirconia gel And yttria gel are preferable examples. Specific examples include water absorbing agents described in JP-A Nos. 7-135033, 8-20716, and 9351857.

  Preferred examples of the plasticizer include phosphate ester compounds, chlorinated paraffins, alkylnaphthalene compounds, sulfone alkylamide compounds, oligoethers, and aromatic nitriles. Examples thereof include plasticizers described in JP-A Nos. 288916 and 2003-317539.

  As the compatibilizer, those having a boiling point or sublimation point of 250 ° C. or higher are preferable, and those having a boiling point or 300 ° C. or higher are more preferable.

  The dope may further contain a polymer other than the polymer serving as the precursor of the solid electrolyte for the purpose of (1) increasing the mechanical strength of the film and (2) increasing the acid concentration in the film.

  Among the above objects, a polymer having a molecular weight of about 10,000 to 1,000,000 and having a good compatibility with the solid electrolyte is suitable for (1). For example, perfluorinated polymers, polystyrene, polyethylene glycol, polyoxetane, polyether ketone, polyether sulfone, and polymers containing two or more polymer repeating units are preferred. Moreover, it is preferable to contain these substances in a dope so that it may become the range of 1 to 30 weight% with respect to the total weight when it is set as a film. The compatibility with the solid electrolyte may be improved by using a compatibilizer. As the compatibilizer, those having a boiling point or sublimation point of 250 ° C. or higher are preferable, and those having a boiling point of 300 ° C. or higher are more preferable.

  Among the above objects, (2) is preferably a polymer having a proton acid site. Examples of such a polymer include perfluorosulfonic acid polymers such as Nafion (registered trademark), sulfonated polyetheretherketone having a phosphate group in the side chain, sulfonated polyethersulfone, sulfonated polysulfone, and sulfonated polybenzimidazole. Examples thereof include sulfonated products of heat-resistant aromatic polymer compounds such as Moreover, it is preferable to contain these substances in a dope so that it may become the range of 1 to 30 weight% with respect to the total weight when it is set as a film.

  Further, when the obtained solid electrolyte film is used in a fuel cell, an active metal catalyst that promotes the oxidation-reduction reaction between the anode fuel and the cathode fuel may be added to the dope. As a result, the fuel that has permeated into the solid electrolyte film from one electrode is consumed in the solid electrolyte without reaching the other electrode, so that the crossover phenomenon can be prevented. The active metal catalyst is not particularly limited as long as it functions as an electrode catalyst, but platinum or an alloy based on platinum is particularly suitable.

[Dope production]
Below, dope used for manufacture of the film of this invention is demonstrated. FIG. 1 shows a dope manufacturing facility according to the present invention. However, the present invention is not limited to the dope manufacturing apparatus and method shown here.

  The dope manufacturing facility 10 includes a solvent tank 11 for storing a solvent, a hopper 12 for supplying a polymer that is a precursor of a solid electrolyte, an additive tank 15 for storing an additive, a solvent and a polymer. A mixing tank 17 for mixing the liquid and the additive into the mixed liquid 16, a heating device 18 for heating the mixed liquid 16, a temperature regulator 21 for adjusting the temperature of the heated mixed liquid 16, A first filtering device 22 that filters the mixed solution 16 exiting the temperature regulator 21 to form a dope 24, a flash device 26 for adjusting the concentration of the dope 24, and a filter for filtering the concentration-adjusted dope 24 A second filtration device 27.

  In addition, the dope manufacturing facility 10 is provided with a recovery device 28 for recovering the solvent generated in the flash device 26 and a regeneration device 29 for regenerating the recovered solvent. The dope manufacturing facility 10 is connected to a film manufacturing facility 33 via a stock tank 32. In addition, although the valves 36-38 for adjusting the amount of liquid feeding and the pumps 41 and 42 for liquid feeding are provided in the dope manufacturing equipment 10, about the increase / decrease in the position and number where these are arrange | positioned It is changed appropriately.

  The flow of manufacturing the dope 24 using the dope manufacturing facility 10 will be described below. By opening the valve 37, the solvent is sent from the solvent tank 11 to the mixing tank 17, and an appropriate amount of polymer is sent from the hopper 12 to the mixing tank 17. From the additive tank 15, an additive solution prepared by previously mixing the additive with a desired solvent is sent to the mixing tank 17 by opening and closing the valve 36. The polymer may be continuously fed to the mixing tank 17 by a feeding means that continuously measures and feeds, or is intermittently fed to the mixing tank 17 by a feeding means that measures and sends a predetermined amount. You may be sent to. Moreover, it is preferable that the solvent used when preparing the additive solution is a solvent used for preparing the dope from the viewpoint of compatibility in the dope.

  In addition to the method of sending the additive as a solution, for example, when the additive is liquid at room temperature, the additive can be fed into the mixing tank 17 in the liquid state. Further, when the additive is solid, a method of feeding into the mixing tank 17 using a hopper or the like is also possible. When a plurality of types of additives are added, a solution in which a plurality of types of additives are dissolved can be placed in the additive tank 15. Alternatively, it is also possible to use a plurality of additive tanks and put a solution in which the additive is dissolved in each of them and send them to the mixing tank 17 through independent pipes.

  In the above description, the order of putting in the mixing tank 17 is the solvent, the polymer, and the additive, but it is not limited to this order. For example, a preferred amount of solvent can be fed after the polymer is fed into the mixing tank 17. In addition, the additive does not necessarily need to be mixed with the polymer and the solvent in the mixing tank 17. First, after preparing a mixture of the polymer and the solvent, it is added to this mixture by an inline mixing method or the like in a later step. May be.

  The mixing tank 17 encloses the outer surface thereof, a jacket 46 supplied with a heat transfer medium between the mixing tank 17, a first stirrer 48 rotated by a motor 47, and a second stirrer 52 rotated by a motor 51, It has. The mixing tank 17 supplies a heat transfer medium to the inside of the jacket 46, and circulates this to adjust the internal temperature. The internal temperature of the mixing tank 17 is preferably in the range of −10 ° C. to 55 ° C. Moreover, the liquid mixture 16 which the polymer swelled with the solvent is obtained by selecting and using the 1st stirrer 48 and the 2nd stirrer 52 suitably. The first stirrer 48 preferably has an anchor blade so that the polymer and the solvent can be efficiently and effectively mixed, and the second stirrer 52 is a dissolver type eccentric stirrer. It is preferable.

  The liquid mixture 16 is sent to the heating device 18 by a pump 41. The heating device 18 is preferably a jacketed tube having a tube body (not shown) and a jacket (not shown) for passing a heat transfer medium between the tube body, and further, the mixed liquid 16 is added. It is preferable to have a pressurizing part (not shown) for pressing. When such a heating device 18 is used, the solid content in the mixed solution 16 can be effectively and efficiently dissolved under heating conditions or under pressure and heating conditions. Hereinafter, a method of dissolving a solid component such as a polymer in a solvent by heating as described above is referred to as a heating dissolution method. In the heating dissolution method, it is preferable to heat the mixed solution 16 so as to be 60 ° C to 250 ° C.

  Further, the solid component may be dissolved in a solvent by a cooling dissolution method instead of the heating dissolution method. The cooling dissolution method is a method of proceeding dissolution while cooling the mixed solution 16 so that the temperature of the mixed solution 16 is maintained or lower. In the cooling dissolution method, the mixed solution 16 is preferably cooled to a temperature of −100 ° C. to −10 ° C. The solid electrolyte can be sufficiently dissolved in the solvent by the heating dissolution method or the cooling dissolution method as described above.

  The mixed liquid 16 is brought to substantially room temperature by the temperature controller 21 and then filtered by the first filtering device 22. Thereby, the dope 24 from which foreign matters such as impurities and aggregates are removed can be obtained. In addition, it is preferable that the average pore diameter of the filter used for the 1st filtration apparatus 22 is 10 micrometers or less so that a micro foreign material can be removed. However, when the pore diameter is too small, the time required for filtering the dope becomes long, so the average pore diameter of the filter is appropriately selected in consideration of the manufacturing time and the like.

  The dope 24 after filtration is sent to the stock tank 32 by the valve 38 and temporarily stored, and then used for film production.

  By the way, as described above, the method in which the solid component is once swollen and then dissolved to form a solution increases the time required for the dope production as the concentration of the solid electrolyte in the solution is increased. May be a problem. In such a case, it is preferable to once make a dope having a concentration lower than the target concentration and then carry out a concentration step to achieve the target concentration. For example, the dope 24 filtered by the first filtering device 22 can be sent to the flash device 26 by the valve 38, and the dope 24 can be concentrated by evaporating a part of the solvent of the dope 24. The concentrated dope 24 is extracted from the flash device 26 by the pump 42 and sent to the second filtration device 27. The temperature of the dope 24 during filtration is preferably 0 ° C to 200 ° C. The dope 24 from which foreign matter has been removed by the second filtration device 27 is sent to the stock tank 32 and once stored, and then used for film production. In addition, since the concentrated dope 24 may contain bubbles, it is preferable to perform a bubble removal process before sending it to the second filtration device 27. As the bubble removal method, for example, various known methods such as an ultrasonic irradiation method for irradiating the dope 24 with ultrasonic waves are applied.

  Further, the solvent gas generated by flash evaporation in the flash device 26 is condensed and recovered as a liquid by a recovery device 28 having a condenser (not shown). The recovered solvent is regenerated and reused as a solvent for dope production by the regenerator 29. Such collection and recycling have advantages in terms of manufacturing costs and are effective in preventing adverse effects on the human body and the environment because they are implemented in a closed system.

  Further, when impurities such as coarse particles and foreign matters are contained in the dope, when the dope is used as a film, there is a possibility that the proton conductivity may be lowered or the film itself may be deteriorated. Therefore, it is preferable to filter the dope using a filtering device at least once in the middle of manufacturing the dope. In addition, the installation number and installation location of the filtering apparatus in the dope manufacturing facility and the number of times of filtering the dope are not particularly limited, and may be determined as necessary.

  By the above manufacturing method, the dope 24 having a precursor concentration of 5 wt% or more and 50 wt% or less can be manufactured. The precursor concentration is more preferably in the range of 10 wt% to 40 wt%. The concentration of the additive is preferably in the range of 1% by weight to 30% by weight when the total solid content in the dope is 100% by weight. In addition, whether the solid content is dissolved in the solvent in the dope 24 can be confirmed by illuminating the filtered dope 24 with a fluorescent lamp.

  Next, the manufacturing method of the solid electrolyte film of this invention is demonstrated. In FIG. 2, the flow of the solid electrolyte film manufacturing process which concerns on this invention is shown. In FIG. 2, only the flow of the process will be described briefly, and details of each process will be described with reference to FIG.

  The solid electrolyte film manufacturing process 60 includes a cast film forming process 63 for forming the cast film 61 from the dope 24 and a precursor film 65 having the precursor as a main component by peeling off the cast film 61 from the support. A stripping step 64, a first drying step 67 for drying the precursor film 65, an acid treatment step 68 for subjecting the precursor film 65 to an acid treatment, and a washing step 69 for washing the precursor film 65 after the acid treatment. And a second drying step 72 that dries the washed precursor film 65 to form a solid electrolyte film 70.

  FIG. 3 shows a film manufacturing facility 33 used when manufacturing a film according to the solid electrolyte film manufacturing process 60 in the present embodiment. The film manufacturing facility 33 is an example of the present invention and does not limit the present invention. Hereafter, the flow at the time of manufacturing a film is demonstrated, describing the detail of each apparatus which comprises the film manufacturing equipment 33. FIG.

  The film production facility 33 includes a casting chamber 80 for casting the dope 24 on a support to form a casting film 61, and a drying means while the casting film 61 is transported as the support travels. A transport chamber 81 for drying the film 61 and a tenter 83 for drying the precursor film 65 formed by peeling the casting film 61 from the support are provided. Further, downstream of the tenter 83, a bathtub 84 and a water tank 85 are provided. And are provided. In addition, a drying chamber 86, a humidity control chamber 87, and a winding chamber 88 are provided downstream of the water tank 85.

  The film manufacturing facility 33 is connected to the dope manufacturing facility 10 via the stock tank 32, and an appropriate amount of the dope 24 can be appropriately fed into the film manufacturing facility 33. The stock tank 32 is provided with a stirrer 91 that is rotated by a motor 90, and the dope 24 that is stored until it is subjected to casting after preparation is constantly stirred by rotating the stirrer 91. The dope 24 is kept in a uniform state by suppressing the precipitation and aggregation of solids.

  The casting chamber 80 includes a casting die 93 that flows out of the dope 24 and a casting band 94 that serves as a traveling support. The casting band 94 is stretched around the rotating rollers 97 and 98, and continuously travels by driving and rotating at least one of the rotating rollers 97 and 98. When manufacturing the film, first, the dope 24 is cast on the casting band 94 running from the casting die 93 in the casting chamber 80. The dope 24 at the time of casting is one in which fine particles larger than a predetermined particle size, foreign matters, gel-like foreign matters and the like are removed by being sent from the stock tank 32 to the filtration device 96 and filtered.

As a material of the casting die 93, precipitation hardening type stainless steel is preferable, and its thermal expansion coefficient is preferably 2 × 10 ⁻⁵ (° C. ⁻¹ ) or less. And it has almost the same corrosion resistance as SUS316 in the forced corrosion test with electrolyte aqueous solution, and even if it is immersed in a mixed solution of dichloromethane, methanol and water for 3 months, pitting (opening) occurs at the gas-liquid interface. Those having corrosion resistance that do not occur are preferred. The casting die 93 is preferably produced by grinding a material that has passed for one month or more after casting. As a result, the dope 24 flows uniformly in the casting die 93, and a flow described later. It is possible to prevent streaks or the like from occurring in the spread film 61. The so-called wetted surface of the casting die 93 in contact with the dope 24 preferably has a finishing accuracy of 1 μm or less in terms of surface roughness and a straightness of 1 μm / m or less in any direction. The slit clearance of the casting die 93 can be adjusted in the range of 0.5 mm to 3.5 mm by automatic adjustment. The chamfer radius R of the corner portion of the liquid contact portion at the tip of the lip of the casting die 93 is constant and 50 μm or less over the entire width of the casting die 93. The casting die 93 is preferably a coat hanger type die.

  The width of the casting die 93 is not particularly limited, but is preferably about 1.1 to 2.0 times the width of the solid electrolyte film 70 as the final product. In addition, a temperature controller that controls the temperature of the casting die 93 is preferably attached to the casting die 93 so that the temperature of the dope 24 during film formation is maintained at a predetermined temperature. Furthermore, it is more preferable that the casting die 93 is provided with a plurality of thickness adjusting bolts (heat bolts) provided at predetermined intervals in the width direction and an automatic thickness adjusting mechanism that adjusts the gap between the slits with the heat bolt. . The heat bolt is preferably subjected to film formation by setting a profile according to the amount of pump 95 (preferably a high precision gear pump) according to a preset program. In order to precisely control the dope feeding amount, the pump 95 is preferably a high-precision gear pump. In addition, a thickness measuring machine such as an infrared thickness gauge is provided in the film manufacturing facility 33, and feedback control to the automatic thickness adjusting mechanism is performed by an adjustment program based on the thickness profile and a detection result by the thickness measuring machine. Also good. It is preferable to use a casting die 93 that can adjust the slit distance of the tip lip to be ± 50 μm or less so that the difference in thickness at any two positions excluding both ends of the solid electrolyte film 70 as a product is within 1 μm. .

It is more preferable that a cured film is formed at the lip end of the casting die 93. The method for forming the cured film is not particularly limited, and examples thereof include ceramic coating, hard chrome plating, and a nitriding method. In the case of using ceramics as the cured film, it is preferable to use a ceramic that can be ground, has a low porosity, is not brittle, has good corrosion resistance, and has no affinity or adhesion to the dope 24. Specific examples include tungsten carbide (WC), Al ₂ O ₃ , TiN, Cr ₂ O _{3 and the} like. Among them, WC is particularly preferable. The WC coating can be performed by a thermal spraying method.

  In order to prevent the dope 24 from locally drying and solidifying at the lip tip of the casting die 93, it is preferable to attach a solvent supply device (not shown) for supplying a solvent to the lip tip in the vicinity of the lip tip. The position where the solvent is supplied is preferably a peripheral portion of a three-phase contact line formed by both ends of the casting bead, both ends of the lip tip, and the outside air. The flow rate of the supplied solvent is preferably 0.1 mL / min to 1.0 mL / min for each side. Thereby, it is possible to prevent foreign matters such as solid components precipitated from the dope 24 and those mixed in the casting bead from the outside from being mixed in the casting film 61. In addition, as a pump which supplies a solvent, it is preferable to use a pulsation rate of 5% or less.

  The width of the casting band 94 is not particularly limited, but it is preferable to use a casting band 94 having a range of 1.1 to 2.0 times the casting width of the dope 24. Further, it is preferable that the length is 20 m to 200 m, the thickness is 0.5 mm to 2.5 mm, and the surface roughness is polished to be 0.05 μm or less.

  The material of the casting band 94 is not particularly limited, and may be, for example, an inorganic material such as stainless steel or a plastic film made of an organic material. Examples of the plastic film include non-woven plastic films such as polyethylene terephthalate (PET) film, polybutylene terephthalate (PBT) film, nylon 6 film, nylon 6,6 film, polypropylene film, polycarbonate film, and polyimide film. It is preferably a long product having chemical stability and heat resistance that can cope with the solvent to be used and the film forming temperature.

  It is preferable to adjust the surface temperature of the casting band 94 using the rotating rollers 97 and 98 having a heat transfer medium attached therein. In the present embodiment, the rotation roller 97, 98 in which a heat transfer medium flow path (not shown) is formed is used to circulate the heat transfer medium whose temperature is adjusted in the flow path, thereby rotating the rotation roller. The surface temperature of 97, 98 is adjusted. However, the surface temperature of the casting band 94 is not particularly limited, and may be appropriately set according to the type of solvent, the type of solid component, the concentration of the dope 24, and the like.

Instead of the rotating rollers 97 and 98 and the casting band 94, a rotating drum (not shown) can be used as a support. In this case, it is preferable that the rotation can be performed with high accuracy so that the rotation speed unevenness is 0.2% or less. The rotating drum preferably has an average surface roughness of 0.01 μm or less, and preferably has a surface subjected to a hard chrome plating treatment or the like. Thereby, sufficient hardness and durability can be improved. In addition, it is preferable that the surface defects of the rotating drum, the casting band 94, and the rotating rollers 97 and 98 are minimized. Specifically, there is no pinhole of 30 μm or more, and the number of pinholes of 10 μm or more and less than 30 μm is 1 / m ² or less, and the number of pinholes of less than 10 μm is preferably ² / m ² or less.

  In the vicinity of the casting die 93, a decompression chamber is provided to control the pressure on the upstream side in the running direction of the casting band 94 of the ribbon-shaped dope 24, that is, the casting bead formed from the casting die 93 to the casting band 94. (Not shown) is preferably provided. Further, it is preferable to provide a blower (not shown) in the vicinity of the casting band 94 and to blow air to evaporate the solvent of the casting film 61. In addition, it is preferable to provide a wind-shielding plate in the above-described air blower to suppress the wind that disturbs the shape of the casting film 61 from hitting the casting film 61. In addition, the casting chamber 80 is provided with a temperature controller for keeping the internal temperature at a predetermined value, and a condenser (condenser) (both not shown) for condensing and recovering the volatile organic solvent. It is done. This capacitor is preferably in the form of being provided with a recovery device for recovering the condensed organic solvent.

When the dope 24 is cast from the casting die 93 onto the casting band 94, the rotating rollers 97 and 98 are adjusted so that the tension generated in the casting band 94 is 10 ³ N / m × 10 ⁶ N / m. The relative position and at least one of the rotational speeds are adjusted. Further, the relative speed difference between the casting band 94 and the rotating rollers 97 and 98 is adjusted to be 0.01 m / min or less. At the time of casting, the casting amount of the dope 24 is determined in consideration of the concentration of the dope 24 to be used and the desired thickness of the film product.

  The speed fluctuation of the casting band 94 is preferably 0.5% or less, and the meandering in the width direction that occurs when the casting band 94 makes one round is preferably 1.5 mm or less. In order to suppress the meandering, a detector (not shown) that detects the positions of both ends of the casting band 94 and a position adjustment that adjusts the position of the casting band 94 according to the detection data by the detector. More preferably, a machine (not shown) is provided to feedback control the position of the casting band 94. In addition, it is preferable that the vertical position variation of the casting band 94 immediately below the casting die 93 with the rotation of the rotary rollers 97 and 98 be within 200 μm. The casting chamber 80 is preferably provided with a temperature controller (not shown), so that the temperature is set to -10 ° C to 57 ° C. Solvent evaporated in the casting chamber 80 is recovered by a recovery device (not shown) and then regenerated and reused as a solvent for dope production, which is also preferable for obtaining effects such as reduction in manufacturing cost.

  In order to stabilize the state of the casting bead, it is preferable to control in the decompression chamber so that the upstream area of the bead has a predetermined pressure value. The reduced pressure value by the decompression chamber is preferably −2500 Pa to −10 Pa from the downstream area with respect to the bead. It is preferable to attach a jacket (not shown) to the decompression chamber so that the internal temperature is kept at a predetermined temperature. In order to keep the shape of the casting bead desired, it is preferable to attach a suction device (not shown) to the edge portion of the casting die 93 to suck both sides of the bead. The edge suction air volume is preferably in the range of 1 L / min to 100 L / min.

  Inside the casting chamber 80, the casting film 94 on the casting band 94 is transported by traveling the casting band 94 by the rotating rollers 97 and 98, and similarly, the inside of the transporting chamber 81 is transported. In the casting chamber 80 or the transfer chamber 81, a drying unit capable of supplying a heater and drying air is provided in the vicinity of the transfer path of the casting band 94, and the drying air is supplied by the drying unit. The drying of the casting film 61 on the casting band 94 is promoted.

  The inside of the transfer chamber 81 is preferably divided into a plurality of sections and adjusted by providing a drying means so that the drying temperature in each section is different. Thereby, since it can be made to dry gradually during conveyance of the casting film 61, shape changes, such as a wrinkle and a twist which generate | occur | produce when the solvent in the casting film 61 volatilizes rapidly, can be reduced. . However, the number of sections is not particularly limited. The drying temperature inside the transfer chamber 81 is preferably 30 ° C. or higher and 60 ° C. or lower. When the casting film 61 is dried as described above, the solvent volatilized from the inside floats in the transfer chamber 81. If this floating solvent is liquefied and adheres to the surface of the casting film 61, the flatness is lowered, which is not preferable. Therefore, in this embodiment, a condenser (condenser) 99 is provided in the transfer chamber 81 to condense and recover the floating solvent.

  A tank 101 that includes a peeling roller 100 and stores a predetermined solution is provided downstream of the transfer chamber 81. In this embodiment, water is used as the solution. A casting band 94 on which the casting film 61 sent out from the transfer chamber 81 is mounted is sent into the tank 101. The solution is preferably a liquid having a lower boiling point than the solvent contained in the cast film 61 and a poor solvent for the solid electrolyte. Since the criteria for this poor solvent have already been explained, the explanation here is omitted. Examples of the solution include a mixture of an organic solvent and water in addition to the above water. As an organic solvent here, it is preferable to use the solvent used for dope preparation. This makes it possible to control the solvent extraction rate in the membrane. Thus, when the casting film 61 is immersed in a solution, the casting film 61 can be made into a gel and have an effect of providing self-supporting properties. Since the cast film 61 is replaced with a solution in which a part of the solvent is immersed, the cast film 61 can be efficiently and effectively dried in the subsequent steps, and as a result, the film production time can be shortened. .

  The time for immersing the casting film 61 in the solution in the tank 101 is not particularly limited, and for example, it may be appropriately adjusted according to the amount of residual solvent contained in the casting film 61 after being immersed in the solution. good. Further, the method for bringing the cast film into contact with the solution is not particularly limited. As a method other than the above immersion, for example, a method of spraying a solution on the surface of the cast film can be mentioned, and the same effect can be obtained by these methods.

  The casting film 61 having the self-supporting property is peeled off from the casting band 94 while being supported by the peeling roller 100 installed in the tank 101 to obtain a precursor film 65. The formed precursor film 65 is conveyed downstream, and excess water adhering to the surface is removed by the air shower 103 provided upstream of the tenter 83. The casting band 94 from which the casting film 61 has been peeled travels endlessly as the rotary rollers 97 and 98 are driven, and is fed into the casting chamber 80 again.

  The precursor film 65 from which excess water has been removed is fed into the tenter 83. The tenter 83 is provided with a drying device that sends out the drying air, and clips 104 that are a number of gripping means that travel as the chain (not shown) travels. And after holding the both ends of the precursor film 65 with the clip 104, while conveying the inside of the tenter 83, drying air is supplied from the above-mentioned drying device to promote drying of the precursor film 65.

  However, in the tenter 83, the clip may be replaced with a pin, and the pin may be transported after being fixed by being pierced at both end portions of the precursor film. At this time, it is preferable to adjust the temperature of the tenter 83 to 80 ° C. or more and 140 ° C. or less by adjusting the temperature of the drying air. In this embodiment, the internal temperature is adjusted to be about 120 ° C. In the present embodiment, it is preferable to divide the inside of the tenter 83 into four different temperature zones and adjust the drying conditions appropriately for each section.

  In the tenter 83, the precursor film 65 can be stretched in the width direction. While the precursor film 65 before being fed into the tenter 83 is transported, the precursor film 65 can be stretched in the transport direction by adjusting the transport tension of the precursor film 65. When the precursor film 65 is stretched, the precursor film 65 is stretched so that at least one of the casting direction and the width direction is 100.5% to 300% of the dimension before stretching. It is preferable. Thereby, the molecular orientation of the precursor film 65 to convey can be adjusted. For the stretching of the precursor film, a tenter may be used as in the present embodiment. In addition to this, a precursor film is provided, and then a transition part in which a large number of rollers are arranged is provided. You may make it extend | stretch in a conveyance direction by adjusting a conveyance speed during conveying.

  An ear clip device 105 is provided downstream of the tenter 83. The edge-cutting device 105 cuts off both end portions of the precursor film 65 previously held by the clip 104. In this way, when both end portions of the precursor film 65 are excised using the ear clip device 105, it is possible to remove a laceration caused by a gripping means such as a clip, and thus it is possible to manufacture a film having excellent flatness. It becomes. In addition, the cut | disconnected both side edge part is sent into the crusher 105a with a cutter blower (not shown), and is crushed and becomes a chip. When this chip is reused as a polymer raw material for dope production, it is possible to effectively use the raw material or reduce production costs. Although the process of cutting the both end portions of the precursor film 65 can be omitted, it is preferable that the process is performed after the film is peeled off from the support as the precursor film 65 and until the film is wound up.

  A bathtub 84 and a water tank 85 are disposed downstream of the ear clip device 105. The bath 84 stores a solution containing an acid, and the water tank 85 stores water adjusted to a predetermined temperature. Then, the precursor film 65 after being eared is fed into the bathtub 84 and immersed in a solution containing an acid. Thereby, the cation species in the polymer constituting the precursor film 65 can be replaced with hydrogen atoms. In addition, it is preferable that the temperature of the solution containing the acid used shall be 30 degreeC or more and 120 degrees C or less. However, the temperature of the solution is not particularly limited as long as it is a temperature range from room temperature to the boiling of the solution. However, the higher the temperature, the faster the precursor film 65 having a high proton substitution rate is obtained. Can do.

  The acid is preferably a compound having an anion formula weight of 40 to 1,000 when ionized. Specific examples of the acid include sulfuric acid, phosphoric acid, nitric acid, and organic sulfonic acid. Among them, it is preferable to use sulfuric acid. In this embodiment, 0.5 mol / L sulfuric acid is used as the acid, and a solution containing the sulfuric acid is heated and kept at 30 ° C.

  When the total number of cation species in the polymer that is the precursor of the solid electrolyte is x, and the total number of hydrogen atoms substituting the cation species is y, a value represented by (y / x) × 100 is referred to as a proton substitution rate. In the present invention, since the precursor film 65 is immersed in the solution containing the acid as described above, the proton substitution rate can be increased efficiently and effectively. The proton substitution rate is preferably 80% or more with respect to the total amount of cation species. More preferably, it is 90% or more.

  The solution containing an acid is preferably brought into contact with the precursor film 65 as uniformly as possible. The method of immersing in a solution containing an acid as in the present embodiment can bring the precursor film 65 into contact with the entire surface. However, a contact method is not specifically limited, A desired solution may be apply | coated to the surface of a precursor film, and the method of spraying a solution on the surface can also be used suitably.

  The precursor film 65 has a proton substitution rate increased in the bathtub 84 and is sent to the water tank 85 as the solid electrolyte film 70. When the solid electrolyte film 70 is immersed in the water stored in the water tank 85 as described above, the solution containing the remaining acid that is not used for the replacement of the cation species and the hydrogen atom can be removed and washed. In this case, it is possible to prevent the polymer or the like constituting the solid electrolyte film 70 from being contaminated by the acid.

  In addition, when washing | cleaning a solid electrolyte film with water, it is not necessarily immersed, and it will not specifically limit if it is the contact method of the water which can remove an acid from a film. For example, the method of apply | coating water with respect to a solid electrolyte film, the method of spraying water, etc. are mentioned. Thus, the method of applying water to the solid electrolyte film or spraying the solid electrolyte film is preferable because it can be carried out while the film is continuously conveyed.

  Of the above, specific examples of the method of spraying water include spray nozzles used for methods such as extrusion, fountain coaters, frog mouth coaters, etc., air humidification and painting, and automatic tank cleaning. The method using is mentioned. These coating methods are summarized in “All about Coating” (Edited by Masayoshi Araki, Processing Technology Research Group (1999)), and this description can also be applied to the present invention. In addition, the spray nozzles can be installed so that the water flow collides with the entire width by arranging spray nozzles such as conical and fan shapes from Ikeuchi Co., Ltd. in the width direction of the transparent resin film. .

  The higher the water spray speed, the higher the cleaning effect can be obtained. However, when the washing process is carried out while continuously transporting the solid electrolyte film, the transport stability may be impaired. Therefore, the spraying speed of water is preferably 50 to 1000 cm / second, preferably 100 to 700 cm / second, and more preferably 100 to 500 cm / second.

The amount of water used for washing is preferably at least an amount exceeding the theoretical dilution rate defined below. The theoretical dilution ratio is a value calculated by the application amount of washing water [ml / m ² ] ÷ contact amount of acid-containing solution [ml / m ² ], that is, all the water used for washing. Define the assumed theoretical dilution factor that contributed to the dilute mixing of the solution containing the contacted acid. In practice, since complete mixing does not occur, the amount of washing water exceeding the theoretical dilution rate is used. Depending on the acid concentration of the solution containing the acid used, the secondary additive, and the type of solvent, a dilution of at least 100 to 1000 times, preferably 500 to 10,000 times, more preferably 1000 to 100,000 times is obtained. Use wash water.

  When a certain amount of water is used as a cleaning method, it is preferable to divide and wash several times rather than apply the whole amount at once. In this case, if an appropriate space is provided by adjusting the time and distance between one cleaning means and the next cleaning means, the solution containing acid can be diluted by diffusing water. preferable. Furthermore, it is preferable that the water on the film flows along the film surface by providing an inclination to the conveyed solid electrolyte film because a mixed dilution effect by flow can be obtained in addition to diffusion. The most preferred method is to provide a draining means between the cleaning means and the cleaning means to drain the solid electrolyte film. This method can also increase the dilution efficiency of a solution containing an acid. Specific examples of draining means include a blade, an air knife, or a roll. A larger number of cleaning means is preferable for enhancing the cleaning effect, but 2 to 10 stages, preferably 2 to 5 stages are usually used from the viewpoint of installation space and equipment cost.

  Among the above draining means, it is preferable to use an air knife in order to obtain the most draining effect. In the case of using an air knife, the amount of moisture remaining on the surface can be brought close to zero by adjusting the air volume and the air pressure sent to the solid electrolyte film. However, if the air volume is too large, fluttering or shifting may occur, which may affect the film conveyance stability. Therefore, the air flow rate is preferably 10 to 500 m / second, preferably 20 to 300 m / second, and more preferably 30 to 200 m / second. Note that the air volume of the air is not particularly limited, and may be determined based on the amount of moisture originally on the film, the transport speed of the film, and the like.

  In addition, in order to remove moisture uniformly, the air velocity distribution in the width direction of the solid electrolyte film is usually within 10%, and preferably within 5%, and the air supply method to the air knife outlet and the air knife. Adjust. The narrower the gap between the surface of the solid electrolyte film to be conveyed and the air knife outlet, the greater the water draining ability, but there is a higher possibility of contact with and damage to the solid electrolyte film. Usually, an air knife is installed with a gap of 10 μm to 10 cm, preferably 100 μm to 5 cm, more preferably 500 μm to 1 cm. Furthermore, by setting a backup roll on the opposite side of the cleaning surface of the solid electrolyte film so as to face the air knife, the setting of the gap can be stabilized and the influence of fluttering, wrinkles, deformation, etc. of the film can be reduced. It is preferable because

When performing cleaning, it is preferable to use pure water. The pure water used in the present invention has a specific electric resistance of at least 1 MΩ or more, particularly metal ions such as sodium, potassium, magnesium and calcium are less than 1 ppm, and anions such as chloro and nitric acid are less than 0.1 ppm. Pure water can be easily obtained by a simple substance such as a reverse osmosis membrane, an ion exchange resin, distillation, or a combination thereof. Among these, ultrapure water that has almost no dissolved oxygen and is theoretically close to H ₂ O is preferable. Moreover, in order to acquire the high effect which removes an acid from a film, it is preferable that the temperature of the water to be used shall be 30 degreeC or more and 120 degrees C or less. However, the temperature of water is not particularly limited as long as it is in the temperature range from approximately room temperature to the boiling of water. In this embodiment, the acid of the precursor film 65 is removed by immersing in warm water adjusted to 30 ° C.

  When the acid treatment and the washing treatment are performed as described above, an effect of removing impurities such as inorganic salts contained therein at the time of forming the cast film can be obtained. Therefore, the resulting film is suppressed from deterioration due to impurities. In addition, it is preferable that the metal content contained in the film after an acid treatment and washing | cleaning is 1000 ppm or less, More preferably, it is 100 ppm or less. In addition, Na, K, Ca, Fe, Ni, Cr, Zn etc. are mentioned as a target metal, These metal contents are grasped | ascertained by measuring with a commercially available atomic absorption photometer, for example. Can do.

  The drying chamber 86 includes a number of pass rollers 107, an adsorption recovery device 108 for recovering the volatile solvent floating inside the drying chamber 86, and a drying device (not shown) for supplying drying air. . Then, while the solid electrolyte film 70 after washing is fed into the drying chamber 86 and conveyed while being supported by the pass roller 107, drying air is supplied from the drying device to dry the solid electrolyte film 70. .

  The interior of the drying chamber 86 is preferably divided into a plurality of sections, and the drying temperature is preferably changed for each section. Thereby, since drying does not advance rapidly, the solid electrolyte film 70 excellent in flatness can be obtained. The internal temperature of the drying chamber 86 is not particularly limited, but is determined according to the heat resistance of the polymer (glass transition point Tg, heat distortion temperature, melting point Tm, continuous use temperature, etc.) and should be Tg or less. In the present invention, the internal temperature of the drying chamber 86 is preferably 120 ° C. or higher and 185 ° C. or lower, and it is preferable to dry the solid electrolyte film 70 until the residual solvent amount is less than 10% by weight. The solvent gas generated by evaporation from the solid electrolyte film 70 is adsorbed and recovered by the adsorption / recovery device 108, and after removing the solvent component, it is sent again into the drying chamber 86 as dry air.

  The film 70 is carried into the humidity control chamber 87. The humidity control chamber 87 is provided with the same plurality of pass rollers 107 as the drying chamber 86, a temperature control device, and a humidity control device (both not shown). Then, while the solid electrolyte film 70 is conveyed while being wound around the pass roller 107, the temperature and humidity are adjusted so as to have a desired temperature and humidity. Since the moisture content of the solid electrolyte film 70 can be controlled by controlling the humidity in this way, curling occurs on the surface of the solid electrolyte film 70 or winding failure occurs during winding. Can be suppressed. The temperature and humidity in the humidity control chamber 87 are not particularly limited, but the temperature is preferably 20 ° C. or higher and 30 ° C. or lower, and the humidity is preferably 40 RH% or higher and 70 RH% or lower.

  It is preferable to provide a cooling chamber (not shown) between the drying chamber 86 and the humidity control chamber 87 to cool the film 70 to approximately room temperature because it is possible to suppress the shape change of the film 70 due to a temperature change. Further, a neutralization device (not shown) such as a neutralization bar is provided downstream of the humidity control chamber 87, and the charged voltage of the solid electrolyte film 70 is adjusted to be within a predetermined range (for example, −3 kV to +3 kV). It is preferable that a knurling roller pair (not shown) is provided, and knurling is preferably applied to both end portions of the solid electrolyte film 70 by embossing. In addition, it is preferable that the uneven | corrugated height of the location which provided the knurling is 1 micrometer-200 micrometers.

  Finally, the solid electrolyte film 70 is fed into the winding chamber 88. The take-up chamber 88 is provided with a take-up roll 110 and a press roller 111 for controlling the tension at the time of take-up, and the solid electrolyte film 70 is wound while being applied with tension by the press roller 111. It is wound on a take-up roll 110. Thereby, the roll-shaped solid electrolyte film 70 can be obtained while suppressing generation | occurrence | production of wrinkles, a twist, etc. In order to prevent excessive winding in the film roll, it is more preferable to gradually change the tension from the start to the end of winding. The width of the solid electrolyte film 70 to be wound is preferably 100 mm or more. However, the present invention is also applied to the production of a thin film having a thickness of 5 μm to 300 μm. The

  In the solution casting method, various steps such as a drying step and a side edge portion excision and removal step are performed before the film (solid electrolyte film) peeled off from the support is wound up. In each of these processes or between each process, the film is mainly supported or conveyed by a roller. These rollers include a driving roller and a non-driving roller, and the non-driving roller is mainly used for determining a film conveyance path and improving conveyance stability.

  In the present embodiment, the case where one kind of dope is cast is shown. However, in the present invention, two or more kinds of dopes may be co-cast simultaneously to form a multilayer cast film. It is also possible to form a multi-layer cast film by co-casting. In the case where two or more kinds of dopes are co-cast simultaneously, a casting die provided with a feed block may be used, or a multi-manifold casting die may be used. However, as for the film which consists of a multilayer by co-casting, it is preferable that any one of the two layers exposed on the surface is 0.5% to 30% of the total thickness of the film. In addition, when co-casting at the same time, when dope is cast from the die slit to the support, the concentration of each dope is adjusted in advance so that the high-viscosity dope is wrapped and cast by the low-viscosity dope. In the bead formed from the die slit to the support, it is preferable that the dope in contact with the outside world, that is, the exposed dope has a larger proportion of the poor solvent than the inner dope.

  Instead of the above-described method for forming a polymer of a solid electrolyte precursor into a film, the solid electrolyte is retained in the pores of a so-called porous substrate having a plurality of pores so that the solid electrolyte becomes pores. Even if the film contained is manufactured, a solid electrolyte film different from the above embodiment can be manufactured. As a method for producing such a solid electrolyte film, a method in which a sol-gel reaction solution containing a solid electrolyte is applied onto a porous substrate and the solid electrolyte is put into pores, and the porous substrate includes a solid electrolyte. There is a method of immersing in a sol-gel reaction solution to fill the solid electrolyte in the pores. Preferable examples of the porous substrate include porous polypropylene, porous polytetrafluoroethylene, porous cross-linked heat-resistant polyethylene, and porous polyimide. Moreover, a solid electrolyte film can also be formed by processing a solid electrolyte into a fiber shape, filling voids in the fiber with other polymer compounds, etc., and forming the film using the fiber. In this case, examples of the other polymer compound for filling the void include the substances mentioned as additives in the present specification.

  The solid electrolyte film of the present invention can be suitably used as a proton conductive membrane for a fuel cell, in particular, a direct methanol fuel cell, and also used as a solid electrolyte film sandwiched between two electrodes of a fuel cell. Can do. Furthermore, as electrolytes, display elements, electrochemical sensors, signal transmission media, capacitors, electrodialysis, electrolytic membranes for electrolysis, gel actuators, salt electrolytic membranes, proton exchange resins in various batteries (redox flow batteries, lithium batteries, etc.) The solid electrolyte film of the present invention can be used.

(Fuel cell)
Hereinafter, an example in which the solid electrolyte film is used for an electrode membrane composite (hereinafter referred to as MEA) and an example in which the electrode membrane composite is used for a fuel cell will be described. However, the modes of the MEA and the fuel cell shown here are examples of the present invention, and the present invention is not limited thereto. FIG. 4 is a schematic cross-sectional view of the MEA. The MEA 131 includes a film 70 and an anode electrode 132 and a cathode electrode 133 that face each other with the film 70 interposed therebetween.

  The anode electrode 132 has a porous conductive sheet 132 a and a catalyst layer 132 b in contact with the film 70, and the cathode electrode 133 has a porous conductive sheet 133 a and a catalyst layer 133 b in contact with the film 70. Examples of the porous conductive sheets 132a and 133a include carbon paper. The catalyst layers 132b and 133b are made of a dispersion in which carbon particles carrying a catalyst metal such as platinum particles are dispersed in a proton conductive material. Examples of the carbon particles include ketjen black, acetylene black, and carbon nanotube. Examples of the proton conductive material include Nafion (registered trademark).

As the manufacturing method of the MEA 131, the following four methods are preferable.
(1) Proton conductive material coating method: A catalyst paste (ink) containing active metal-carrying carbon, proton conductive material, and solvent is directly applied to both surfaces of the film 70, and the porous conductive sheets 132a and 133a are applied to the (heat) coating layer. A MEA having a five-layer structure is manufactured by pressure bonding.
(2) Porous conductive sheet coating method: After a liquid containing the material of the catalyst layers 132b and 133b, for example, a catalyst paste, is applied to the surfaces of the porous conductive sheets 132a and 133a to form the catalyst layers 132b and 133b. Then, the film 70 is pressure-bonded to form a MEA 131 having a five-layer structure.
(3) Decal method: a catalyst paste is applied on PTFE to form catalyst layers 132b and 133b, and then only the catalyst layers 132b and 133b are formed on the film 70 to form a three-layer structure. The sheets 132a and 133a are pressure-bonded to produce a MEA 131 having a five-layer structure.
(4) Post-catalyst support method: After coating and forming a film 70, porous conductive sheets 132a, 133a or PTFE with an ink in which a platinum non-supported carbon material is mixed with a proton conductive material, the film is applied to a liquid containing platinum ions. 70 is impregnated, and platinum particles are reduced and deposited in the film to form the catalyst layers 132b and 133b. After the formation of the catalyst layers 132b and 133b, the MEA 131 is produced by the above methods (1) to (3).

  However, the method of making the MEA is not limited to the above method, and various known methods can be applied. For example, in addition to the above methods (1) to (4), there are the following methods. A coating solution containing the materials of the catalyst layers 132b and 133b is prepared in advance, and this coating solution is applied to a support and dried. The support on which the catalyst layers 132b and 133b are formed is pressure-bonded on the both surfaces of the film 70 so that the catalyst layers 132b and 133b are in contact with the film 70, respectively. And after peeling a support body, the film 70 in which the catalyst layers 132b and 133b were formed in both surfaces is pinched | interposed with the porous conductive sheets 132a and 133a. And MEA can be manufactured by closely contacting the porous conductive sheets 132a and 133a and the catalyst layers 132b and 133b.

  FIG. 5 is a schematic view of a fuel cell. The fuel cell 141 includes an MEA 131, a pair of separators 142 and 143 that sandwich the MEA 131, a current collector 146 made of a stainless net attached to the separators 142 and 143, and a packing 147. An anode pole side opening 151 is provided in the anode pole side separator 142, and a cathode pole side opening 152 is provided in the cathode pole side separator 143. Gas fuel such as hydrogen and alcohols (such as methanol) or liquid fuel such as an alcohol aqueous solution is supplied from the anode electrode side opening 151, and oxidant gas such as oxygen gas and air is supplied from the cathode electrode side opening 152. Is supplied.

  A catalyst in which active metal particles such as platinum are supported on a carbon material is used for the anode electrode 132 and the cathode electrode 133. Commonly used active metal particle sizes are in the range of 2 to 10 nm. However, the smaller the particle size, the greater the surface area per unit weight, which increases the activity and is advantageous. However, if it is too small, it is difficult to disperse without agglomeration, so about 2 nm is said to be the small limit. .

  The active polarization in the hydrogen-oxygen fuel cell is larger in the cathode electrode, that is, the air electrode than in the anode electrode, that is, the hydrogen electrode. This is because the rate of the cathode electrode reaction, that is, the oxygen reduction reaction, is slower than that of the anode electrode. For the purpose of improving the activity of the oxygen electrode, various platinum-based binary metals such as Pt—Cr, Pt—Ni, Pt—Co, Pt—Cu, and Pt—Fe can be used. In a direct methanol fuel cell using a methanol aqueous solution as the anode fuel, in order to suppress catalyst poisoning by CO generated during the oxidation process of methanol, Pt—Ru, Pt—Fe, Pt—Ni, Pt—Co, and Pt—Mo are used. Pt-Ru-Mo, Pt-Ru-W, Pt-Ru-Co, Pt-Ru-Fe, Pt-Ru-Ni, Pt-Ru-Cu, Pt-Ru-Sn, etc. A platinum group ternary metal such as Pt—Ru—Au can be used. As the carbon material for supporting the active metal, acetylene black, Vulcan XC-72, ketjen black, carbon nanohorn (CNH), and carbon nanotube (CNT) are preferably used.

The catalyst layers 132b and 133b are generated by (1) transporting the fuel to the active metal, (2) providing a field for the oxidation (anode electrode) and reduction (cathode electrode) reaction of the fuel, and (3) oxidation / reduction. And (4) transports protons generated by the reaction to the solid electrolyte, that is, the film 70. For (1), the catalyst layers 132b and 133b are made porous so that liquid and gaseous fuel can permeate deeply. For (2), the active metal catalyst supported on the carbon material is responsible, and (3) is also responsible for the carbon material. In order to fulfill the function (4), a proton conductive material is mixed in the catalyst layers 132b and 133b. The proton conductive material of the catalyst layer is not limited as long as it is a solid having a proton donating group, but is represented by a polymer compound having an acid residue used for the film 70, for example, Nafion (registered trademark). Preferable examples include sulfonated products of heat-resistant aromatic polymers such as perfluorosulfonic acid, side chain phosphate group poly (meth) acrylate, sulfonated polyetheretherketone, and sulfonated polybenzimidazole. When the solid electrolyte used as the material of the film 70 is used for the catalyst layers 132b and 133b, the catalyst layers 132b and 133b and the film 70 are the same type of material, so that the electrochemical adhesion between the solid electrolyte and the catalyst layer is increased. This is more advantageous in terms of ion conduction. It is suitable from a viewpoint of battery output and economical efficiency to make the usage-amount of an active metal into the range of 0.03-10 mg / cm < ² >. The amount of the carbon material supporting the active metal is preferably 1 to 10 times the weight of the active metal. The amount of the proton conductive material is preferably 0.1 to 0.7 times the weight of the active metal-carrying carbon.

  The catalyst layers 132b and 133b are also referred to as an electrode base material, a permeable layer, or a backing material, and play a role of preventing current collection and deterioration of gas permeation and accumulation of water. Usually, carbon paper or carbon cloth can be used, and polytetrafluoroethylene (PTFE) treated for water repellency can be used.

MEA is incorporated into a battery, preferably having an area resistance value of 3Omucm ² below by the AC impedance method in a state filled with fuel, more preferably those of 1 .OMEGA.cm ² or less, and most preferably those 0.5Omucm ² below. The area resistance value is obtained from the product of the actually measured resistance value and the area of the sample.

  What can be used as a fuel of a fuel cell will be described. Examples of the anode fuel include hydrogen, alcohols (such as methanol, isopropanol, and ethylene glycol), ethers (such as dimethyl ether, dimethoxymethane, and trimethoxymethane), formic acid, borohydride complex, and ascorbic acid. Examples of the cathode fuel include oxygen (including oxygen in the atmosphere) and hydrogen peroxide.

In a direct methanol fuel cell, a methanol aqueous solution having a methanol concentration of 3 wt% to 64 wt% is used as an anode fuel. According to the anode reaction formula (CH ₃ OH + H ₂ O → CO ₂ + 6H ⁺ + 6e ⁻ ), 1 mol of water is required for 1 mol of methanol, and the methanol concentration at this time corresponds to 64% by weight. The higher the methanol concentration, there is an advantage that the weight and volume of the battery including the fuel tank with the same energy capacity can be reduced. However, the higher the methanol concentration, the more so-called crossover phenomenon that methanol permeates the solid electrolyte and reacts with oxygen on the cathode side to lower the voltage, and the output tends to decrease. Therefore, the optimum concentration is determined by the methanol permeability of the solid electrolyte used. The cathode reaction formula of the direct methanol fuel cell is (3/2) O ₂ + 6H ⁺ + 6e ⁻ → H ₂ O, and oxygen (usually oxygen in the air) is used as the fuel.

  As a method of supplying the anode fuel and the cathode fuel to the respective catalyst layers 132b and 133b, (1) a method of forcibly feeding using an auxiliary device such as a pump (active type), and (2) an auxiliary device There are two methods that are not used, for example, a passive type in which the fuel is exposed to the atmosphere by exposing the catalyst layer to the atmosphere due to capillary action or natural fall when the fuel is a liquid, and ( It is also possible to combine 1) and (2). (1) has the advantage that by extracting the water produced on the cathode side, high-concentration methanol can be used as the fuel, and high output can be achieved by air supply, but a fuel supply system is provided. Therefore, there is a drawback that miniaturization is difficult. Although (2) has the advantage that it can be downsized, it has a drawback that the fuel supply is likely to be rate-limiting and it is difficult to produce a high output.

  Since the single cell voltage of the fuel cell is generally 1 V or less, the single cells are used by stacking in series according to the required voltage of the load. As the stacking method, “planar stacking” in which single cells are arranged on a plane and “bipolar stacking” in which single cells are stacked via separators having fuel flow paths formed on both sides thereof are used. The former is suitable for a small fuel cell because the cathode electrode (air electrode) comes out on the surface, so that air can be easily taken in and can be made thin. In addition to this, a method of applying MEMS technology, performing fine processing on a silicon wafer, and stacking has been proposed.

  Fuel cells are considered for various uses such as for automobiles, homes, and portable devices.In particular, direct methanol fuel cells are advantageous in that they can be reduced in size and weight and do not require charging. It is expected to be used as an energy source for various portable devices and portable devices. For example, mobile devices that can be preferably applied include mobile phones, mobile laptop computers, electronic still cameras, PDAs, video cameras, portable game machines, mobile servers, wearable personal computers, mobile displays, and the like. Examples of portable devices that can be preferably applied include portable generators, outdoor lighting devices, flashlights, and electric (assist) bicycles. It can also be preferably used as a power source for industrial or household robots or other toys. Furthermore, it is also useful as a power source for charging secondary batteries mounted on these devices.

  Next, examples of the present invention will be described. In each of the following Examples, Examples 1 to 3 are examples of embodiments of the present invention, and Examples 4 to 9 are comparative experiments with respect to Examples 1 to 3.

The dope A was prepared by the dope manufacturing equipment 10 shown in FIG. Note that, in the compound represented by Chemical Formula 3 shown above, Dope A is X = Na, Y = SO ₂ , Z is the structure represented by Chemical Formula 4 (I), and n = 0.33, m = 0.67, 100 parts by weight of compound A having a number average molecular weight Mn of about 61,000 and a weight average molecular weight Mw of about 159000, and 256 parts by weight of dimethyl sulfoxide as a good solvent for compound A And 171 parts by weight of methanol, which is a poor solvent for Compound A, were prepared.

[Production of solid electrolyte film]
The dope A is cast from the casting die 93 onto the traveling casting band 94 to form a casting film 61, and 45 ° C / 10% RH dry air is blown from the blower to the casting film 61 for 30 minutes. Dried. The casting band 94 was made of a PET film. Next, the casting film 61 placed on the casting band 94 is immersed in a tank 101 in which water (warm water) adjusted to 30 ° C. is stored, and then removed from the casting band 94 by the peeling roller 100. The cast film 61 was peeled off as the precursor film 65. During this time, the total immersion time of the casting film 61 and the precursor film 65 in the tank 101 including the peeling time was 5 minutes.

  Subsequently, the water adhering to the surface of the gel-like precursor film 65 sent out from the tank 101 was drained using the air shower 103, and then the precursor film 65 was sent into the tenter 83. In the tenter 83, while conveying both ends of the precursor film 65 while being held by the clips 104, a drying air of 120 ° C. is supplied from the drying device so that the residual solvent amount of the precursor film 65 is less than 10% by weight. Dried until The drying time with the tenter 83 was 10 minutes. Then, both ends of the precursor film 65 that was released from the tenter 83 by releasing the clip 104 were cut by the ear-cutting device 105.

  The precursor film 65 whose both end portions were cut was sent into a bath 84 in which a 0.5 mol / L sulfuric acid aqueous solution maintained at 70 ° C. was stored, and acid treatment was performed. Thereby, the cation seed | species contained in the precursor film 65 was substituted by the hydrogen atom, and the solid electrolyte film 70 was obtained. Moreover, the solid electrolyte film 70 removed the acid by sending it into the water tank 85 in which 70 ° C. water was stored.

  In Example 1, another water tank was provided downstream of the water tank 85 to wash the solid electrolyte film 70. The second water tank used was a hot water stored at 70 ° C. Thereafter, an air shower (not shown) was provided between the drying chamber 86 and the water adhering to the surface of the solid electrolyte film 70 was blown away. Thereafter, the solid electrolyte film 70 was fed into the drying chamber 86 and dried. In the drying chamber 86, while being conveyed while being wound around a large number of pass rollers 107, drying air is supplied from a drying device provided inside the drying chamber 86, and the internal temperature is adjusted to 60 to 120 ° C. did. Then, after the dried solid electrolyte film 70 was sent to the humidity control chamber 87 to adjust the humidity, it was wound around the winding roller 110 in the winding chamber 88 to obtain a roll film.

  With respect to the manufactured solid electrolyte film 70, the following items were measured and their characteristics were evaluated. The following measurements are common to all Examples 1 to 9, and the evaluation results in each Example are summarized in Table 1.

[Proton substitution rate]
After the weight of the manufactured solid electrolyte film 70 was measured, it was immersed in a 0.1 mol / L NaOH aqueous solution for 2 hours for alkali treatment. During the immersion, the NaOH aqueous solution was stirred. Next, with respect to the NaOH aqueous solution from which the solid electrolyte film was taken out, the ion exchange capacity (ICE) of the solid electrolyte film 70 was determined by performing back titration with a hydrochloric acid aqueous solution. Then, the ion exchange capacity was compared with the theoretical value, and the amount of the cation species of the polymer that is the precursor of the solid electrolyte substituted with protons in the acid treatment was calculated, and this was evaluated as the proton substitution rate. In addition, said theoretical value is the introduction amount of sulfonic acid groups derived from structural analysis by NMR measurement or the like.

[Proton conductivity]
The proton conductivity was measured using the four-terminal AC method according to Journal of the Electronic Society 143, No. 4, 1254-1259 (1996).

  First, the produced solid electrolyte film 70 was cut into a length of 2 cm and a width of 1 cm, and this was used as a sample. Next, the above sample was placed on a PTFE plate with four platinum wires fixed at intervals of 5 mm, and a PTFE plate was further placed thereon, and these were fixed with screws to form a test cell. Then, using this test cell and a combination of Solartron 1480 type and 1225B type as an impedance analyzer, proton conductivity was measured by an AC impedance method in 80 ° C. on-water.

[Fuel cell power density]
The output density of the fuel cell 141 manufactured using the manufactured solid electrolyte film 70 was measured by the following method.

(1) Preparation of catalyst sheet A as catalyst layers 132b and 133b After mixing 2 g of platinum-supporting carbon in which 50 wt% of platinum was supported on Vulcan XC72 and 15 g of a 5% alcohol solution containing Nafion (registered trademark), this mixture was mixed. Dispersion A was obtained by dispersing with an ultrasonic disperser for 30 minutes. The average particle size of the particles contained in the dispersion A was about 500 nm. Next, the dispersion A was coated on a polytetraethylene film containing a reinforcing material (manufactured by Saint-Gobain Co., Ltd.) and dried, and the resulting product was punched into a circle having a diameter of 9 mm.

(2) Production of MEA 131 After the catalyst sheet A was laminated so that the coating film made of the dispersion A was in contact with the solid electrolyte film 70 on both surfaces of the solid electrolyte film 70, thermocompression bonding was performed at 210 ° C. and 3 MPa for 10 minutes. . And after lowering temperature from 210 degreeC in the state which applied the pressure, the support body of the catalyst sheet A was peeled, and MEA was produced in order.

(3) Output density of fuel cell 141 After stacking a gas diffusion electrode (manufactured by E-TEK) cut to the same size as the electrode on the MEA obtained in (2), this is used as a standard fuel cell test cell (Electrochem) Set). Then, this test cell is connected to a fuel cell evaluation system (As-510, manufactured by NF Circuit Design Block Co., Ltd.), and humidified hydrogen gas is allowed to flow to the anode side, and humidified simulated atmosphere is allowed to flow to one cathode side. Until the voltage stabilizes. Next, a current-voltage characteristic generated when a load was applied between the anode electrode and the cathode electrode was recorded, and this was measured as a power density (W / cm ² ).

In Example 2, the solid electrolyte film 70 was manufactured using the dope B prepared by mixing the following raw materials. Compound B means that among the compounds represented by Chemical Formula 3, X = Na, Y = SO ₂ , and Z is Chemical Formula 4 where (I) is 0.7 mol% and (II) is 0.3 mol. % Compound. Compound B has n = 0.33 and m = 0.67, the number average molecular weight Mn is about 68,000, and the weight average molecular weight Mw is about 200,000.
Compound B 100 parts by weight Dimethyl sulfoxide 200 parts by weight Methanol 135 parts by weight

  A solid electrolyte film 70 was manufactured using the dope B according to the conditions and manufacturing method of Example 1. However, the casting film 61 on the casting band 94 was dried by supplying air at 45 ° C./10% RH for 20 minutes.

  A film 70 was produced in the same manner as in Example 2 except that the 0.5 mol / L sulfuric acid aqueous solution stored in the bath 84 was kept at 80 ° C.

  The solid electrolyte film 70 was manufactured without performing the acid treatment and the washing treatment under the same production conditions and production method as in Example 2. Moreover, when performing the measurement regarding a film, the film formed in the following method was used as a sample.

  As a procedure for producing a sample, first, a film cut piece obtained by cutting a part of the manufactured solid electrolyte film 70 was immersed in a 0.5 mol / L sulfuric acid aqueous solution and boiled for 2 hours. Next, after the film cut piece taken out from the sulfuric acid aqueous solution was rinsed twice with ultrapure water, the film cut piece was boiled for 2 hours.

  A film 70 was produced in the same manner as in Example 2 except that the 0.5 mol / L sulfuric acid aqueous solution stored in the bathtub 84 was maintained at 20 ° C.

  A film 70 was manufactured in the same manner as in Example 2 except that the temperature of water stored in the water tank 85 was 20 ° C.

  A film 70 was manufactured in the same manner as in Example 2 except that the temperature of water stored in a water tank newly provided downstream of the water tank 85 was 20 ° C.

  A film 70 was produced in the same manner as in Example 2 except that the bath 84 in which a 1 mol / L hydrochloric acid aqueous solution kept at 70 ° C. was stored was used.

In Example 9, the solid electrolyte film 70 was manufactured using the dope C prepared by mixing the following raw materials. Compound C is X = H and Y = SO ₂ of the compound represented by Chemical Formula ₃ , and Z is Chemical Formula 4 in which (I) is 0.7 mol% and (II) is 0.3 mol%. It is a compound. Compound B has n = 0.33, m = 0.67, a number average molecular weight Mn of about 68,000, and a weight average molecular weight Mw of about 200,000.
Compound C 100 parts by weight Dimethyl sulfoxide 200 parts by weight Methanol 135 parts by weight

  And the solid electrolyte film 70 was manufactured using dope B with the conditions and the manufacturing method of Example 2. However, the temperature inside the drying chamber 86 was adjusted to 120 to 185 ° C., and the solid electrolyte film 70 after the ears were dried.

  From the results of each Example, in Examples 1 to 3 according to the present invention, the proton conductivity, the proton substitution rate, and the power density are all excellent values for use as a solid electrolyte film product. I understand. In addition, although the result of Examples 1-3 was able to perform a film manufacturing process continuously by incorporating an acid treatment and a washing process, the acid treatment and the washing process were separated from the film manufacturing process as a conventional method. Compared with the results of Example 4 performed in the above, there is no inferiority. Example 9 is a conventional method using a dope made of a proton-substituted polymer in order to obtain a film having high proton conductivity. The solid electrolyte film obtained by this method has high proton conductivity, Proton substitution rate and power density are inferior. This is thought to be due to the polymer being affected by temperature and humidity during the film manufacturing process.

  Further, from the results of Examples 5 and 8, it can be seen that the temperature and formula amount of the acid solution used during the acid treatment affect the proton conductivity and the proton substitution rate. Furthermore, from the results of Examples 6 and 7, it is confirmed that the proton conductivity is high depending on the temperature of water when the acid-treated solid electrolyte film is washed, but the proton substitution rate is affected. Can do.

  Based on the above results, the present invention continuously detects proton conductivity in spite of incorporating acid treatment and washing treatment in a series of steps from formation of a cast membrane to production of a solid electrolyte film. It can be seen that a solid electrolyte film having a high proton substitution rate can be produced. Moreover, when the solid electrolyte film obtained by the present invention is used as a solid electrolyte layer of a fuel cell, an excellent output density can be realized.

It is the schematic of an example of the dope manufacturing equipment used by this embodiment. It is a manufacturing-process figure of the film which concerns on this invention. It is the schematic of an example of the film manufacturing equipment which concerns on this invention. It is sectional drawing of an electrode membrane composite. It is sectional drawing of a fuel cell.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Dope manufacturing equipment 24 Dope 33 Film manufacturing equipment 61 Casting film 65 Precursor film 70 Solid electrolyte film 84 Bathtub 85 Water tank

Claims (14)

A first step of continuously forming a cast film on a traveling support by casting a dope containing an organic solvent and a polymer having a cationic species and a precursor of a solid electrolyte from a casting die;
A second step of peeling off the casting film from the support to form a precursor film made of the precursor;
A third step in which the precursor film is brought into contact with a solution of an acid that is a proton donor while being conveyed to form a solid electrolyte film made of the solid electrolyte in which the cation species are replaced with hydrogen atoms;
A fourth step of washing the solid electrolyte film;
A fifth step of drying the solid electrolyte film,
The method for producing a solid electrolyte film, wherein the first to fifth steps are continuous.   The contact is at least one of immersion of the precursor film into the solution, spraying of the solution onto the precursor film, and application of the solution onto the precursor film. A method for producing a solid electrolyte film.   3. The method for producing a solid electrolyte film according to claim 1, wherein the washing is performed by bringing the solid electrolyte film into contact with water.   The method for producing a solid electrolyte film according to any one of claims 1 to 3, wherein the acid is a compound having a formula weight of 40 to 1000 when ionized when ionized.   5. The method for producing a solid electrolyte film according to claim 1, wherein the temperature of the solution is 30 ° C. or more and 120 ° C. or less.   The method for producing a solid electrolyte film according to any one of claims 3 to 5, wherein the temperature of the water is 30 ° C or higher and 120 ° C or lower.   The method for producing a solid electrolyte film according to claim 1, wherein the polymer is a hydrocarbon-based polymer.   The method for producing a solid electrolyte film according to claim 7, wherein the hydrocarbon polymer is an aromatic polymer. 9. The method for producing a solid electrolyte film according to claim 8, wherein the aromatic polymer is a copolymer composed of structural units represented by general formulas (I) to (III) of Chemical Formula 1.

(However, X is a cationic species, Y is SO ₂ , Z is the structure shown in Chemical Formula (I) or (II), and n and m are 0.1 ≦ n / (m + n) ≦ 0.5)

  The method for producing a solid electrolyte film according to any one of claims 1 to 9, wherein a liquid having a boiling point lower than that of the organic solvent and a poor solvent for the polymer is brought into contact with the cast film. A casting film forming apparatus comprising: a running support; and a casting die for casting a dope containing a polymer that has an organic solvent and a cationic species and is a precursor of a solid electrolyte;
A transport device that transports the precursor film that is the cast film peeled off from the support, and an acid solution that is a proton donor are brought into contact with the precursor film that is transported by the transport device. An acid contact device for forming a solid electrolyte film comprising the solid electrolyte in which the cation species are replaced with hydrogen atoms;
A washing device for washing the solid electrolyte film to remove the acid that has been involved in the substitution;
A solid electrolyte film manufacturing facility, comprising: a drying device that dries the washed solid electrolyte film.   A solid electrolyte film produced by the production method according to claim 1.   The solid electrolyte film according to claim 12, an anode electrode that is provided in close contact with one surface of the solid electrolyte film and generates protons from a hydrogen-containing substance supplied from the outside, and the other of the solid electrolyte film And a cathode electrode for synthesizing water composed of the proton passing through the solid electrolyte film and a gas supplied from the outside.   The electrode membrane composite according to claim 13, and a current collector provided in contact with the electrode of the electrode membrane composite for transferring electrons to and from the anode electrode and the cathode electrode. Fuel cell.

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