JPS62126557A - Thin battery - Google Patents

Abstract

PURPOSE:To make performance uniform and improve adhesion of positive active material with a current collector by making ink with a positive mix and organic solvent, inking a current collector, and drying to form a positive electrode. CONSTITUTION:A positive mix ink is applied to a positive current collector 2 by screen printing, and dried to form a positive electrode 4. The current collector 2 is required to be stable against positive active material, electrolyte, and organic solvent. therefore, for example, a film obtained by laminating an aluminum foil on a conductive film prepared by dispersing carbon filler in polyolefin resin is used as the current collector. Thereby, adhesion of positive active material with current collector is increased and performance of the battery is made uniform.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is a thin battery with particularly excellent performance. The present invention relates to an IE clumping agent having the following properties.

<Prior Art> In recent years, as watches, desks, cameras, toys, etc. have become more electronic, batteries have become smaller and thinner, and button-shaped batteries and flat batteries have come on the market.

Among them, an A4 body made of aluminum S and conductive plastic film? The thin battery used is more flexible than the gold A4a' JA Button Kitaike, and has 44 other advantages such as a larger area and the ability to make two types of arbitrary shapes. have.

The thinning of batteries is not only due to the need for smaller size;
It is also highly anticipated from the point of view of its integrated use with thin products such as denosprays, printed matter, and photographic films.

In the conventional TLI type tube, no pressure is applied between the leakage body and the positive electrode mixture layer, so the tightness between the Tosei body and the positive electrode mixture layer is reduced.
x To maintain the quality of water, emulsions such as etherified starch, hydroxyethyl cellulose, water-soluble polymers such as hollyvinyl alcohol, vinyl acetate emulsions, and acrylic acid ester emulsions m II! .

Alternatively, dispersion binders such as polytetrafluoroethylene dispersion have been used.

The problem that the present invention is trying to solve Because of this, the dispersibility of the positive electrode mixture was poor, resulting in non-uniformity in battery performance. In addition, if it is used in an emulsion resin or dispersion binder, when it is mixed with a positive electrode mixture and frozen to form an ink, the emulsion/dispersion is likely to be destroyed and aggregated, making it impossible to place it on the assembly with a uniform film thickness. (It had become.

More positive electrode mixture? Since water γ is used as a solvent for ink formation, is there a binder other than water-soluble, polymer, emulsion, or dispersion as mentioned above? Cathode active material that cannot be used? A binder that does not reduce and has good adhesion to dot bodies? The downside of not being able to use it? had.

Particularly chemically stable polyolefin resin lI & Volume resistivity 1 created by hot dispersing carbon filler as the main component
A laminate film of conductive film of 05Ω・α or less and aluminum 4: When used in an assembly, it will be completely vaporized when sealing the battery. By holding and heat sealing, it is possible to create a battery that is completely sealed and has excellent leakage resistance. but,
Are conventionally proposed water-soluble polymers, emulsions, and suspension binders also water-based? When the ink is made into an ink and placed on the IT body, the ink is repelled by the assemblage and cannot be applied uniformly, and the adhesiveness between the assemblage and the binder is extremely poor.

Means to solve the problem The present invention has been made in response to the above-mentioned current situation.

IE polar mixture containing E4 active material and organic binder χ? By making an ink using an organic lubricant, placing it on a four-component book, and drying it to create a positive electrode, the positive electrode mixture is extremely well dispersed and uniformly applied, and has good adhesion to the assembly. A thin battery with uniform battery performance and little deterioration over time? This is what we provide.

<Example> What follows is the present invention? An embodiment will be described in detail with reference to the drawings.

The positive electrode mixture used in this example is shown below. A formulation example of 9 positive electrode mixtures made into ink using organic solvents? show.

The positive electrode mixture is applied to the E@a core body (2) shown in FIG. 1 to a thickness of 200 μm by ink screen printing, and is dried to form a positive electrode 14) 2. Here, the positive electrode active material (2) needs to be stable to organic solvents, so in this example, a conductive film made by dispersing carbon filler in a polyolefin resin was used. Laminated film? Using.

The conductive film is not only chemically stable, but also heat-sealed when sealing the battery. What is the advantage of being completely sealed? have.

In this example, the powdered positive electrode active material in the above positive electrode mixture ink formulation example was 100mesh,'! Passed electrolytic manganese dioxide? Acetylene black was used as the conductive agent. The organic binder needs to be selected depending on the material of the current collector, the type of positive electrode active material, and the type of organic solvent used. The organic binder has the binding properties of the compressed active material and has good adhesion to the aggregate, and is the active material of the city.
Non-reducing ￥: It is necessary to choose one example: t・ma ethyl cellulose or low chlorinated polyolefin? Blended? Using.

Next, the organic solvent is stable to the above-mentioned positive substance.

Said LE polar mixture? Is it something that can be uniformly dispersed and the organic binder? Any material that can be dissolved may be used.

In this example, the E4 mixture ink was printed by screen printing. Since it is applied to the Tosei body, it is also suitable for screen printing.
Diethylene glycol or diethyl ether as an agent? Using.

Furthermore, as shown in FIG. 2, a tanari-kameike Nγ was prepared using the regular one-year α4 (41Y) constructed as described above.

In other words, in this double-type battery, the positive electrode (4) is made of perchlorate and lead water. A separator (5) made of impregnated polyester nonwoven fabric is inserted, and a negative 1i mixture I6) made of salivary lead powder and a binder is used as a negative electrode at body 17).
The periphery of the core pond facing the negative electrode coated with K? It is made by sealing with a three-layer insulating film consisting of polyethylene/polyethylene terephthalate/polyethylene.

Effect〉 Thin at pond N prepared as described above and methyl acrylate 6
0 parts, 40 parts of methyl methacrylate? An emulsion created by emulsion polymerization? E+ mixture used by Mizukai for the original image binder? The same standard battery F3-, except that it was used with a positive electrode made from ink, applied to a Tonari book and dried, was prepared, and as shown in Fig. 3, the change in internal resistance over time when stored at <60°C? It was measured. As is clear from the figure, the battery internal resistance does not increase in the 4-way game pond N of the present invention compared to the conventional thin type B. This is positive electrode activity $! This is because the adhesion between the J quality and the aggregate is excellent and this adhesion does not change significantly even after long-term storage.

Furthermore, 137,100 pieces of the above-mentioned thin battery N were made 6
Storage at 0°C for 20 days Dispersion of eccentric utilization and utilization rate when discharging under constant resistance of 117.5 KΩ? Shown in Table 1.

As is clear from Table 1, the usage name of the thin battery N of the present invention has less variation than that of the conventional thin battery B. This is because the upper electrode mixture is evenly divided by the organic solvent, so the battery performance remains constant, and the adhesion between the IT body and the positive electrode mixture does not change even after long-term storage. It is.

In this example, a neutral salt-based aqueous solution 2 was used as the ITD liquid, but the present invention is a neutral salt-based water bath solution. Is it not limited to the thin battery used, but is it a non-aqueous solvent? It can also be used in lithium-manganese batteries and the like. Conventional non-aqueous core medium decomposition liquid? Is polytetrafluoroethylene dispersion mainly used as a binder for batteries? However, as shown in the present invention, is E4 mixture used? Since the ink is made using a medium (multiple binders can be used, the adhesion of E4 TEPCO and E electrode mixture, which was considered a drawback in the past, is improved, and the performance of the positive electrode is improved. Since it is possible to prepare the mixture without using water, it also has the advantage that the dehydration process of the IE and ifu mixtures is simplified.

<Effects of the Invention> The present invention is as described above, and the E polar mixture? Positive electrode Kf obtained by forming ink with an organic solvent and drying it on 44 bodies
fl￥: Due to the batteries used in thin-shaped ponds, the dispersibility of the King-4 mixture is good and the battery characteristics are uniform? Furthermore, the adhesion between the iE active material stirrup and the Tousei body was good, and the retention stability was improved. A thin battery with an extremely high industrial value can be obtained.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of IE polarization obtained by a beautiful example of the present invention.
Figure 2 shows a 4-type battery using the positive electrode shown in Figure 1.
FIG. 2 is a table showing storage characteristics in a °C atmosphere.

Claims (1)

[Scope of Claims] 1) In a thin battery having a positive electrode in which a positive electrode mixture containing a positive electrode active material and an organic binder is placed on a current collector and then dried, the positive electrode mixture is formed into an ink. A thin battery characterized by containing an organic solvent. 2) The thin battery according to claim 1, wherein the organic binder is insoluble in the electrolyte and soluble in the organic solvent. 3) The thin battery according to claims 1 and 2, wherein the current collector is formed by laminating aluminum foil on a conductive film made of polyolefin resin with carbon filler dispersed therein.