JP3054335B2 - Manufacturing method of organic electrolyte battery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an organic electrolyte battery comprising a positive electrode, a negative electrode and an organic solvent solution in which a salt is dissolved in an aprotic organic solvent as an electrolytic solution.

[0002]

2. Description of the Related Art In recent years, electronic devices have been remarkably reduced in size, thickness, and function, and accordingly, demands for smaller, thinner, lighter, higher-capacity, and higher-output batteries used as power sources have increased. ing. In particular, in the field of portable electronic devices, there is a strong demand for secondary batteries that are lightweight and can be repeatedly used by charging.

In order to reduce the weight of a secondary battery, it is effective to use an organic semiconductor having a lower density as an electrode active material than metals such as nickel, cadmium, and lead used in conventional secondary batteries. It is.

[0004] Japanese Patent Application Laid-open No. Hei 2
JP-A-220368 discloses an aprotic organic solvent solution of a compound capable of generating an ion which can be doped into an electrode by using an insoluble and infusible substrate having a polyacene skeleton structure as an organic semiconductor as a positive electrode and a negative electrode by electrolysis. An organic electrolyte battery characterized by being used as an electrolyte is disclosed.
The battery comprises an insoluble and infusible substrate having a polyacene skeleton structure, which is an organic semiconductor having a low density, as an electrode and a suitable binder.
Is used, and a sheet-shaped product is used, so that the battery is lightweight and has high performance.

JP-A-63-301460 discloses that an insoluble and infusible substrate having a polyacene skeleton structure is mixed with a binder, and the mixture is subjected to pressure molding, or application or compression on a support. A method for producing a battery electrode characterized in that it is attached is disclosed. However, when a battery is manufactured using the electrode, a sufficiently dried electrode is wound or laminated through a separator to produce a battery, but a part of the electrode active material is peeled off during winding or lamination,
There has been a problem that the leakage current of the battery increases due to the peeled material penetrating through the separator or dropping into the battery case.

[0006]

SUMMARY OF THE INVENTION As a result of intensive studies, the present inventors have found that when manufacturing an organic electrolyte battery, a molded body layer comprising a specific insoluble and infusible substrate and a specific binder is adhered onto a metal foil. The positive electrode, and the negative electrode, containing a solvent, after winding or lamination through a separator, by performing drying, found that the leakage current of the battery is reduced, completed the present invention, An object of the present invention is to provide a method for manufacturing a battery having a small leakage current.

Another object of the present invention is to separate the electrode active material,
An object of the present invention is to provide an organic electrolyte battery that does not fall off.

Still another object is to provide an organic electrolyte battery having high capacity and high reliability.

Further objects and advantages of the present invention will become apparent from the following description.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to provide an organic electrolyte battery comprising a positive electrode, a negative electrode, and an organic solvent solution obtained by dissolving a salt in an aprotic organic solvent as an electrolyte. Insoluble and infusible substrate containing a polyacene skeleton structure having a hydrogen atom / carbon atom ratio of 0.05 to 0.5 and a fluorine atom / carbon atom (F / C) The atomic ratio of which is 0.75 or more,
After a molded body layer made of a binder, which is a fluorine-containing polymer of 1.5 or less, is adhered on a metal foil, a solvent is contained in the positive electrode, and the negative electrode is wound or laminated through a separator. And drying is achieved by a method for producing an organic electrolyte battery.

The aromatic condensation polymer in the present invention is a condensation product of an aromatic hydrocarbon compound having a phenolic hydroxyl group and an aldehyde. As the aromatic hydrocarbon compound, for example, so-called phenols such as phenol, cresol and xylenol are suitable, but not limited thereto. For example,

Embedded image (Where x and y are each independently 0, 1 or 2
Methylene bisphenols represented by the formula: or hydroxy biphenyls or hydroxynaphthalenes. Of these, phenols are particularly preferred in practice.

As the aromatic condensation polymer in the present invention, a part of the above-mentioned aromatic hydrocarbon compound having a phenolic hydroxyl group is replaced with an aromatic hydrocarbon compound having no phenolic hydroxyl group, for example, xylene, toluene, aniline and the like. A modified aromatic condensation polymer substituted with, for example, a condensate of phenol, xylene and formaldehyde can be used, and a modified aromatic polymer substituted with melamine or urea can also be used. Furan resins are also suitable.

As the aldehyde, aldehydes such as formaldehyde, acetaldehyde and furfural can be used, but formaldehyde is preferred. The phenol formaldehyde condensate may be any of a novolak type, a resol type, or a mixture thereof.

The insoluble infusible substrate in the present invention is a heat-treated product of the above-mentioned aromatic condensation polymer and can be produced, for example, as follows.

An inorganic salt such as zinc chloride or sodium phosphate is mixed with the above-mentioned aromatic condensation polymer. Thereby, porosity can be provided to the insoluble and infusible substrate.
The amount to be mixed varies depending on the type of the inorganic salt and the shape and performance of the target electrode, but the weight ratio is 10/1 to 1/7.
Is preferred. When a porous substrate having a communicating hole is to be obtained, the inorganic salt is preferably used in an amount of 2.5 to 10 times the weight of the aromatic condensation polymer. The mixture of the inorganic salt and the aromatic condensation polymer thus obtained is formed into a desired shape such as a film or a plate.
The composition is cured by heating at a temperature of 0 to 180 ° C. for 2 to 90 minutes.

The cured product thus obtained is then placed in a non-oxidizing atmosphere at a temperature of 400 to 800 ° C., preferably 45 ° C.
Temperature of from 0 to 750 ° C., particularly preferably 500 to 700
Heat to a temperature of ° C. By this heat treatment, the aromatic condensation polymer undergoes a dehydrogenation dehydration reaction, and a polyacene skeleton structure is formed by the condensation reaction of the aromatic ring.

This reaction is a kind of thermal condensation polymerization, and the degree of reaction is represented by an atomic ratio represented by hydrogen atoms / carbon atoms (hereinafter, referred to as H / C) in the final product. The value of H / C of the insoluble infusible substrate is 0.05 to 0.5, preferably
0.1 to 0.35. When the value of H / C of the insoluble and infusible substrate is larger than 0.5, the electric conductivity is not preferred because the polyacene skeleton structure is not developed. On the other hand, H /
If the value of C is smaller than 0.05, carbonization has progressed too much, and the performance as an electrode constituent material is low.

The resulting heat-treated body is sufficiently washed with water or dilute hydrochloric acid to remove the inorganic salts contained in the heat-treated body.

Thereafter, the resultant is dried to obtain an insoluble and infusible substrate.

The insoluble and infusible substrate is subjected to X-ray diffraction (CuK
According to α), the position of the main peak is represented by 2θ and 2
4 ° or less, and 41 to 41 in addition to the main peak.
There is another broad peak between 46 °.

That is, it is suggested that the aromatic polycyclic structure has a polyacene skeleton structure in which the aromatic polycyclic structure is appropriately developed and has an amorphous structure, and that it can be stably doped and undoped with ions, so that it is useful as an active material for an electrode. is there.

The shape of the insoluble and infusible substrate used in the present invention is as follows:
There is no particular limitation as long as it can be molded, such as a powder or a short fiber. However, in consideration of moldability, a powder having an average particle diameter of 100 μm or less is desirable.

The binder used in the present invention has an atomic ratio of fluorine atom / carbon atom (hereinafter sometimes referred to as F / C).
Is not less than 0.75 and not more than 1.5, more preferably not less than 0.75 and not more than 1.3. When F / C exceeds 1.5, the capacity of the battery cannot be sufficiently obtained. When it is less than 0.75, the binder dissolves in the electrolytic solution. Examples of the fluorine-containing polymer that satisfies the above conditions include polyvinylidene fluoride, vinylidene fluoride-trifluoroethylene copolymer, ethylene-tetrafluoroethylene copolymer, and propylene-tetrafluoroethylene copolymer. Further, a fluorine-containing polymer in which hydrogen in the main chain is substituted with an alkyl group can also be used. In the case of polyvinylidene fluoride, F / C is 1, and in the case of vinylidene fluoride-3 fluoroethylene copolymer, when the molar fraction of vinylidene fluoride is 50%,
At 80%, the F / C becomes 1.25 and 1.1, respectively.
Further, in the case of a propylene-tetrafluoroethylene copolymer, when the propylene mole fraction is 50%, the F / C becomes 0.75. Among them, polyvinylidene fluoride and a vinylidene fluoride-3fluoroethylene copolymer having a molar fraction of vinylidene fluoride of 50% or more are preferable, and polyvinylidene fluoride is practically preferable.

The fluorinated polymer in the present invention preferably exhibits selective solubility, that is, a solvent having low solubility in an electrolyte and a soluble solvent. For example, in the case of polyvinylidene fluoride, it is preferably used in an electrolyte. Hardly soluble in carbonate-based solvents, etc.
It can be dissolved in N, N-dimethylformamide, N-methylpyrrolidone and the like.

The electrode in the battery of the present invention comprises at least the insoluble and infusible substrate and the specific fluoropolymer described above, and can be produced, for example, as follows. The insoluble infusible substrate, the specific fluorine-containing polymer,
A solvent or a dispersion medium is sufficiently mixed and molded. The proportion of the fluorine-containing polymer varies depending on the shape and particle size of the insoluble and infusible substrate, the strength and shape of the intended electrode, and is preferably 2% to 50% by weight relative to the insoluble and infusible substrate.
Preferably it is 5% to 30%. As a solvent, N, N
-Dimethylformamide, N-methylpyrrolidone, N,
A solvent such as N-dimeracetamide that can dissolve the above-mentioned fluorine-containing polymer is preferable. In the mixture, even if the fluorinated polymer is completely dissolved, even if only a part of the fluorinated polymer is dissolved, there is no particular problem. It is preferable for obtaining an electrode. The viscosity of the mixture can be controlled by the amount of the solvent. An electrode is obtained by applying the mixture adjusted to an appropriate viscosity on a metal foil, drying, and pressing if necessary.

The electrode of the present invention is formed by adding a binder to the above-mentioned insoluble and infusible substrate, and may add a conductive material as needed. Although the kind of the conductive material is not particularly limited, for example, a carbon-based material such as activated carbon, carbon black, and graphite is preferable, and the smaller the particle size, the more effective. The ratio of the conductive material varies depending on conditions such as the electric conductivity of the insoluble and infusible base powder and the type of binder, but is required to be 2 to 40 wt%.

As the metal foil in the present invention, a metal having corrosion resistance, for example, aluminum, copper, stainless steel, nickel or the like can be used. Aluminum foil is particularly desirable in consideration of oxidation resistance and light weight.

The electrode in the present invention contains a solvent, and the contained solvent is a solvent used when mixing the above-mentioned specific insoluble and infusible substrate with the above-mentioned binder, for example, N, N
-Dimethylformamide, N-methylpyrrolidone, N,
N-dimethylacetamide and the like are preferred, but not particularly limited thereto. The content thereof varies depending on the drying conditions, but is preferably from 10 to 50%, more preferably from 20 to 50% by weight of the insoluble and infusible substrate.
４０40%. If it is less than 10%, the adhesive force is reduced,
If it exceeds 50%, it becomes viscous.

The organic electrolyte battery according to the present invention comprises a positive electrode comprising the above-mentioned specific insoluble and infusible substrate formed by the above-mentioned method and a molded layer comprising a specific binder adhered on a metal foil, and a negative electrode comprising a solvent. It is manufactured using an electrode containing, for example, it can be manufactured as follows. A positive electrode terminal and a negative electrode terminal are connected to the positive electrode and the negative electrode containing a solvent, respectively, and wound through a separator. The wound electrode and separator are inserted into the battery case, and the positive electrode terminal and the negative electrode terminal are connected to the top lid and the battery case, respectively, and then dried at 150 ° C. under reduced pressure. After drying, the electrolyte is injected and sealed. Battery

The organic electrolyte battery of the present invention is a heat-treated product of an aromatic condensed polymer and has an insoluble infusible material containing a polyacene skeleton structure having an atomic ratio of hydrogen atom / carbon atom of 0.05 to 0.5. An aprotic organic solvent solution of a compound capable of generating ions that can be doped into the electrode by electrolysis is used as an electrolyte, with a molded body layer made of a conductive substrate and a specific binder adhered on a metal foil as a positive electrode and a negative electrode. .

Compounds which can be used in the electrolytic solution and can form ions which can be doped into the electrode include alkali metal or tetraalkylammonium or tetraalkylphosphonium halides, perchlorates, hexafluorophosphates, and 6-fluorophosphates. Arsenate, tetrafluorophosphate and the like, and specifically, LiI, NaI, NH ₄ I, LiClO ₄ , L
iA ₃ F ₅ , LiBF ₄ , KPF ₆ , NaPF ₆ , R ₄
NClO ₄ , R ₄ NASF, R ₄ NPF ₆ , R ₄ NB
F ₄ R ₄ PCO ₄ , R ₄ PAsF, R ₄ PPF ₆ ,
R ₄ PBF ₄ (R represents the same or different alkyl group) and the like.

Examples of the aprotic organic solvent for dissolving the compound include ethylene carbonate, propylene carbonate, γ-butyrolactone, sulfolane, acetonitrile, dimethoxyethane, tetrahydrofuran, methylene chloride, and mixtures thereof. It is important to select in consideration of the solubility of the compound, battery performance, and the like.

The concentration of the compound in the electrolytic solution is most preferably at least 0.1 mol / l, usually from 0.2 to 1.
A preferred result is obtained when the content is in the range of 5 mol / l.

Next, an example of an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram illustrating the basic configuration of a battery according to the present invention. In FIG. 1, (1) is a positive electrode, and (2) is a negative electrode. (3) and (3 ') are metal foils which are wound via a separator (5) arranged for the purpose of preventing contact between the positive and negative electrodes and holding the electrolytic solution. The positive electrode and the positive electrode terminal (8), and the negative electrode and the negative electrode terminal (8 ') are connected so as not to cause a voltage drop.

The separator is a porous material having continuous holes for the electrolyte or the electrode active material and having no electron conductivity, and is usually a cloth, nonwoven fabric or porous material made of glass fiber, polyethylene, polypropylene, or the like. ,
And electrolytic condenser paper. The thickness of the separator is preferably thin, but is determined in consideration of the amount of retained electrolyte, flowability, strength, and the like.

The wound positive and negative electrodes and the separator are inserted into the battery case, and the positive and negative terminals are respectively connected to the top lid (7) and the battery case. The top lid is provided with a safety valve for preventing the battery from bursting and the like, and is sealed with an insulating packing (4) between the top lid and the battery case. The shape and size of the electrodes are the shape of the target battery,
It is appropriately determined according to the performance.

The shape of the battery of the present invention may be a coin type, a cylindrical type, a square type, a box type, or the like which satisfies the above-mentioned basic structure, and the shape is not particularly limited.

[0038]

The method for producing an organic electrolyte battery according to the present invention comprises a positive electrode comprising the above-mentioned specific insoluble and infusible substrate and a specific binder formed on a metal foil, and a negative electrode comprising a solvent. After being wound or laminated via a separator, drying is performed.
It can prevent the electrode active material from peeling and falling off, and is suitable as a method for producing an organic electrolyte battery. The organic electrolyte battery manufactured by the method of the present invention has characteristics that are preferable as an organic electrolyte battery because the leakage current is significantly reduced by preventing the active material from falling off.

Hereinafter, the present invention will be described specifically with reference to examples. Here, part of the electrode active material during winding or lamination
Is peeled, the peeled material penetrates through the separator, or the battery case
The negative effects such as dropping into the battery can be measured by measuring the leakage current of the battery.
And evaluated.

[0040]

EXAMPLE 1 An aqueous solution obtained by mixing a water-soluble resole (about 60% concentration) / zinc chloride / water at a weight ratio of 10/25/4 was used for 100 m.
After pouring into a m × 100 mm / 2 mm mold and covering a glass plate thereon to prevent moisture from evaporating, the mixture was heated at a temperature of about 100 ° C. for 1 hour to be cured.

The phenol resin was placed in a silicon unit electric furnace, and heated at a rate of 40 ° C./hour under a nitrogen stream, and heat-treated to 500 ° C. Next, the heat-treated product was washed with diluted hydrochloric acid, washed with water, and then dried to obtain a plate-shaped insoluble and infusible substrate. The insoluble and infusible substrate thus obtained was pulverized with a nylon ball mill to give an average particle size of 2
A μm insoluble infusible substrate powder was obtained.

The specific surface area of the powder by the BET method is 20.
00m is a ² / g, an atomic ratio of hydrogen atoms / carbon atoms by elemental analysis was 0.24.

A slurry was obtained by sufficiently mixing 100 parts by weight of the insoluble infusible base powder, 20 parts by weight of carbon black as a conductive material, and 10 parts by weight of polyvinylidene fluoride as a binder and 350 parts by weight of N, N-dimethylformamide. Obtained. The slurry is coated with a conductive paste of Bunny Height T602 manufactured by Nippon Graphite Industry Co., Ltd., and coated on a 50 μm-thick aluminum foil provided with a conductive thin film, and in an inert gas atmosphere, at 70 ° C. for 30 minutes, further at 130 ° C. , 5
Dried for 2 hours and pressed to a thickness of 200 μm, solvent content 3
A 5% positive electrode and a negative electrode were used.

The positive electrode terminal and the negative electrode terminal of the positive electrode and the negative electrode (4 × 35 cm ² ) were respectively connected to each other, and wound through a separator. After inserting the wound positive and negative electrodes and the separator into the battery case, connecting the positive electrode terminal and the negative electrode terminal to the top lid and the battery case, respectively, performing drying under reduced pressure at 150 ° C. for 15 hours, injecting the electrolytic solution, and sealing. Figure 1
A cylindrical battery as described above was assembled. As the separator, a 50 μm thick electrolytic capacitor paper was used. Aluminum terminals having a thickness of 150 μm and a width of 5 mm were used as positive and negative terminals. In addition, a solution obtained by dissolving Et ₄ NBF ₄ at a concentration of 1 mol / l in propylene carbonate was used as the electrolytic solution.

The above battery was charged at a constant current and a constant voltage (a set voltage of 2.5 V and a maximum current of 50 mA), and the leakage current after 15 hours was evaluated to be 0.24 mA.

Comparative Example 1 The electrode having a thickness of 200 μm obtained in Example 1 was further
After drying under reduced pressure at 0 ° C. for 15 hours to form a positive electrode and a negative electrode having a solvent content of 0%, a cylindrical battery similar to that in Example 1 was assembled without drying, and the leakage current was evaluated under the same conditions as in Example 1. did. The results are summarized in Table 1.

[0047]

[Table 1]

As is apparent from Table 1, the organic electrolyte battery produced by the method of the present invention is obtained by adhering a molded body layer comprising the above specific insoluble and infusible substrate and a specific binder on a metal foil. After the positive electrode and the negative electrode contain a solvent, and are wound or laminated via a separator and then dried, the leakage current of the battery is significantly reduced.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a basic configuration of a battery according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Positive electrode 2 Negative electrode 3 3 'metal foil 4 Insulating packing 5 Separator 6 Battery case 7 Top lid 8 Positive terminal 8' Negative terminal

Continuation of the front page (72) Inventor Shizukuni Yada 2-6-13 Miyanishi, Harima-cho, Kako-gun, Hyogo Examiner Mitsuji Uzene (56) References JP-A-6-203833 (JP, A) JP-A Sho JP-A-5-29023 (JP, A) JP-A-5-28986 (JP, A) JP-A-5-28985 (JP, A) JP-A-4-34870 (JP, A) A)

Claims (3)

(57) [Claims] 1. A heat-treated aromatic condensation polymer for producing an organic electrolyte battery comprising a positive electrode, a negative electrode, and an organic solvent solution in which a salt is dissolved in an aprotic organic solvent as an electrolytic solution. An insoluble infusible substrate containing a polyacene-based skeleton structure having a hydrogen atom / carbon atom ratio of 0.05 to 0.5 and a fluorine atom / carbon atom (F / C) atomic ratio of 0.75 or more, A positive electrode formed by adhering a molded layer made of a binder which is a fluorine-containing polymer having a thickness of 0.5 or less on a metal foil, and a negative electrode containing a solvent.
A method for producing an organic electrolyte battery, comprising winding or laminating through a filter and then drying. 2. The method for producing an organic electrolyte battery according to claim 1, wherein the fluorinated polymer is polyvinylidene fluoride. 3. The method for producing an organic electrolyte battery according to claim 1, wherein the metal foil is an aluminum foil.