JP3256986B2 - Coin type non-aqueous 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 coin-type non-aqueous electrolyte battery, and more particularly to a coin-type non-aqueous electrolyte battery in which the electrical contact between a positive electrode can and a positive electrode pellet inside the battery is improved to increase the heavy load discharge capacity. The present invention relates to a coin-type nonaqueous electrolyte battery.

[0002]

2. Description of the Related Art A so-called non-aqueous electrolyte battery using a non-aqueous electrolyte as an electrolyte is known as a battery having a high discharge voltage, a high energy density, a low self-discharge, and excellent storage stability. As applications thereof, demands for heavy load characteristics such as electronic calculators, cameras, radios and the like are increasing year by year, in addition to electronic wristwatches and various memory backup power supplies that are required to be used for a long period of 5 to 10 years.

FIG. 3 shows an example of the structure of a conventional nonaqueous electrolyte battery. In FIG. 3, reference numeral 1 denotes a light alloy such as an alkali metal such as lithium and a lithium alloy, and an alkaline earth metal. Reference numeral 2 denotes a positive electrode pellet, which is formed by using a transition metal oxide such as manganese dioxide or vanadium pentoxide, or a transition metal chalcogen compound such as iron sulfide as a positive electrode active material. Negative electrode active material 1
The positive electrode pellet 2 is housed in a negative electrode can 4 and a positive electrode outer can 5 with a non-woven fabric separator 3 made of polypropylene interposed therebetween. The positive electrode outer can 5 is caulked and sealed at its open end via a sealing gasket 6. As the electrolyte, for example, a non-aqueous electrolyte obtained by dissolving a lithium salt as an electrolyte in a non-aqueous solvent (organic solvent) is used.

[0004] In the conventional coin-type nonaqueous electrolyte battery constructed as described above, a conductive paint is applied to the surface facing the positive electrode pellet on the positive electrode outer can in order to improve the electrical contact with the positive electrode pellet. The one that has been applied is used. At present, the conventional coin-type nonaqueous electrolyte battery described above has a poor heavy-load characteristic and does not have a sufficiently satisfactory performance for each application.

[0005] As one means for solving such a problem,
In order to improve the electrical contact between the positive electrode can and the positive electrode pellet, a method using a net, expanded metal, or punched metal as the positive electrode current collector is used.In this case, the expanded metal and punched metal have a porosity. When the size is small, it is not preferable because an active material having a required electric capacity cannot be held in the same volume. In the case of a net, the porosity is large, but the method of press-molding the positive electrode pellet is to fill the positive electrode mixture powder and the net in a predetermined mold or to fill the preformed positive electrode mixture and the net. After that, it is manufactured by pressure molding, but when it is taken out from the mold, the molded product expands in the radial direction or thickness direction, causing a so-called springback phenomenon, and the side where the net is attached and the side where it is not "Warpage" may occur due to the difference in stretching force at the time. When such a positive electrode pellet is used, peeling of the net or cracking of the positive electrode at the time of closing the battery occurs, and the net has low mechanical strength, and is easily deformed particularly after being punched into a required shape. There was a drawback, and it was a problem.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve such problems and drawbacks of the prior art. In a coin-type non-aqueous electrolyte battery, a positive electrode can and a positive electrode pellet are used. By interposing a conductive powder as a current collector between the positive electrode pellet and the positive electrode pellet in a form integrally formed therebetween, the electric contact between the positive electrode outer can and the positive electrode pellet inside the battery is improved, thereby reducing the weight. It is an object to provide a coin-type nonaqueous electrolyte battery having a large load discharge capacity.

[0007]

The coin-type nonaqueous electrolyte battery according to the present invention uses a positive electrode outer can made of nickel-plated stainless steel and a graphite current collector made of graphite or carbon as a positive electrode current collector. A powder is interposed between the positive electrode outer can and the positive electrode pellet in a form integrally molded with the positive electrode pellet, and the filling area occupied by the graphite or carbon powder in the positive electrode pellet is the positive electrode outer can.正極 or more of the area of the positive electrode pellet in contact with.

By doing so, the electrical contact between the positive electrode can and the positive electrode pellet inside the battery is improved,
This is to improve heavy load characteristics. In addition, by using this conductive powder as the positive electrode current collector, an effect was also obtained in reducing the “warpage” of the pellet generated during the formation of the positive electrode pellet.

[0009]

The coin-type nonaqueous electrolyte battery according to the present invention has a structure in which a powder of conductive graphite or carbon as a positive electrode current collector is molded integrally with the positive electrode pellet. Characterized by being interposed. By doing so, the electrical contact between the positive electrode can and the positive electrode pellet inside the battery is improved, and the heavy load characteristics are improved.

[0010]

An embodiment of the present invention and a conventional comparative example will be described below with reference to the drawings. -Example-Fig. 1 is an example of a coin-type nonaqueous electrolyte battery of the present invention. First, as a positive electrode, 89 parts by weight of manganese dioxide, 9 parts by weight of graphite, and 2 parts by weight of polytetrafluoroethylene, which were heat-treated at 350 ° C. for 4 hours, were homogeneously mixed and preformed, and then aluminum powder (average particle size: 45 μm) Was charged into a preformed positive electrode pellet and weighed 0.02 g, followed by pressure molding to produce a positive electrode pellet 2 having an outer diameter of 15.5 mm and a weight of 0.995 g. This aluminum powder is indicated by reference numeral 2A as a positive electrode current collector. On the other hand, a negative electrode was prepared by punching out metal lithium 1 into an outer shape of 15.5 mm, a height of 0.58 mm, and a weight of 0.058 g.

The metallic lithium 1 is pressed against a negative electrode can 4 made of nickel-plated stainless steel, a nonwoven fabric separator 3 made of polypropylene is placed on the negative electrode can 4, and a plastic sealing gasket 6 is placed on top of the separator 3 via a separator 3. Then, an electrolytic solution was dropped from above. Further, the above-mentioned positive electrode pellet 2 is placed thereon with the aluminum layer not facing the severator, and a positive electrode outer can 5 made of nickel-plated stainless steel is covered thereon, and the end is sealed by caulking. 20mm, height 3,2mm
Was manufactured. This was designated as battery A.

As an electrolytic solution, an organic electrolytic solution was used in which propylene carbonate and 1.2-dimethoxyethane were mixed at a volume ratio of 1: 1 and dissolved in a lithium perchlorate ratio of 0.5 mol / 1. -Comparative Example- For comparison, a battery which does not use an aluminum layer as a current collector between a positive electrode can and a positive electrode pellet, which is a conventional method, was also prepared.

In this battery, an aluminum layer is not used as a current collector between the positive electrode can and the positive electrode pellet, and a conductive paint (for example, conductive paint Electroduck 114 manufactured by Nippon Aison Co., Ltd.) is applied to the positive electrode can. All were the same as the examples except that they were applied in the same area and in contact with the pellets. This was designated as Battery B. The above prepared battery A,
With respect to B, discharge characteristics were measured in a 25 ° C. atmosphere at a load of 1 KΩ. FIG. 2 shows the measurement results of the discharge characteristics.

From FIG. 2, it can be seen that the battery A of the embodiment has a performance that is excellent in heavy load discharge with a small impedance rise and a large discharge capacity as compared with the battery B of the comparative example.
In this embodiment, aluminum powder was used as the positive electrode current collector 2A.
Titanium, nickel, platinum, tantalum, or alloys such as stainless steel and Inconel, as well as graphites, carbons, and conductive polymers can be used. Also, the filling area occupied by the conductive powder in the positive electrode pellet,
Preferably, the area is at least の of the area of the pellet in contact with the positive electrode can.

Incidentally, the powder described herein includes a short fiber. As a positive electrode active material, a mixture of manganese dioxide and graphite and PTFE was compression-molded and used as a positive electrode pellet.In addition, transition metal oxides such as vanadium pentoxide, chalcogen compounds, and further, these oxides were used. It is possible to use a complex compound of a chalcogen compound and lithium.

Although the nickel-plated stainless steel is used for the positive electrode can 5, a laminated steel material of aluminum, aluminum and stainless steel, nickel or the like can also be used.

As the electrolyte, for example, an electrolyte obtained by dissolving a lithium salt in an organic solvent is used. Here, the organic solvent is not particularly limited, but for example, propylene carbonate, ethylene carbonate, diethyl carbonate, 1,2-dimethoxyethane, 1,2-diethoxyethane, γ-butyrolactone, tetrahydrofuran, 3-dioxolan, 4-methyl-1,3-
A single solvent such as dioxolan, diethyl ether, sulfolane, methylsulfolane, acetonitrile, propionitrile and the like, or a mixture of two or more solvents can be used. Conventionally known electrolytes can be used, such as LiClO ₄ , Li
AsF ₆ , LiPF ₆ , LiBF ₄ , LiB (C
_{6 H 5) 4, LiCl,} LiBr, CH 3 SO 3 Li,
CF ₃ SO ₃ Li and the like.

[0017]

As described above, the present invention provides a coin-type non-aqueous electrolyte battery using a nickel-plated stainless steel as a positive electrode outer can,
As a positive electrode current collector, a powder made of graphite or carbon is interposed between the cathode outer can and the positive electrode pellet in a form in which a powder made of graphite or carbon is integrally molded with the positive electrode pellet, and a powder made of graphite or carbon is added to the positive electrode pellet. The filling area occupied by the positive electrode can and the positive electrode inside the battery can be improved by improving the electrical contact between the positive electrode can and the positive electrode pellet inside the battery by making the area more than 1/2 of the area of the positive electrode pellet in contact with the positive electrode can. Type non-aqueous electrolyte battery can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a coin-type non-aqueous electrolyte battery according to the present invention.

FIG. 2 is a characteristic diagram showing discharge curves and impedance characteristics of a battery A to which the present invention is applied and a conventional battery B;

FIG. 3 is a cross-sectional view showing a conventional coin-type non-aqueous electrolyte battery.

[Explanation of symbols]

1 Metal lithium, 2 Positive electrode pellet, 2A Positive current collector, 3 Sebalator, 4 Negative electrode can, 5 Positive outer can, 6 Seal gasket seal

Claims (1)

(57) [Claims] 1. A positive electrode outer can made of nickel-plated stainless steel and a positive electrode current collector made of graphite or carbon.
That the powder was in the positive electrode pellet and shape of integrally molded is interposed between the positive electrode outer can and the positive electrode pellets, and the Seikyokupe
Powder made of the above graphites and carbons into the let
The positive electrode having a filling area occupied by a body and in contact with the positive electrode outer can
A coin-type non-aqueous electrolyte battery, wherein the area of the pellet is not less than 1/2 of the area of the pellet .