JPH0359950A - Organic solvent battery - Google Patents

Abstract

PURPOSE:To prevent a ceramic powder from dropping and lower the contact resistance between a cathode lead plate and a cathode active mass sheet by forming a conductive ceramic layer and sandwiching the layer between them by applying or dropping a solution added with a nonionic surfactant to which at least either titanium carbonate and/or titanium nitride is dispersed. CONSTITUTION:A conductive ceramic powder containing a titanium carbide and/or a titanium nitride powder is dispersed in ethanol to which poly (propylene glycol ethylene oxide adduct-based nonionic surfactant is added to give a paste. The paste is applied to the plane of a cathode lead plate 6 facing to a cathode active mass sheet 2 to form a conductive ceramic layer 8. The resulting conductive ceramic layer 8-bearing cathode lead plate 6 is placed in one of open planes of an insulating frame 5 while the plate 6 is brought into contact with the cathode active mass sheet 2. In this way, since the ceramic powder is prevented from dropping, sealing defects are prevented and an organic solvent battery having lowered inner resistance is obtained.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention provides a battery using an organic solvent as an electrolyte, in which the contact resistance between the positive electrode mixture sheet and the positive terminal plate is small, and the contact resistance is low during storage. The present invention also relates to an organic solvent battery in which internal resistance does not increase.

(Prior Art) In recent years, organic solvent batteries whose electrolyte is a solution of an electrolyte dissolved in an organic solvent such as propylene carbonate or 1,2-dimethoxyethane have been widely used in electronic devices.

In particular, as electronic devices such as electronic rate calculators, electronic wristwatches, and IC cards become smaller and thinner, extremely thin flat batteries with a thickness of 1 mm or less are required.

As shown in FIG. 2, this type of flat organic solvent battery consists of a positive electrode mixture sheet 12 made of a positive electrode active material, a conductive material, and an adhesive, and a negative electrode sheet 14 made of metallic lithium, which are laminated with a separator 13 interposed therebetween. The periphery of the power generation unit 11 is surrounded by an annular insulating frame 15 made of heat-weldable modified polyethylene, modified polypropylene, or ionomer resin, and one opening of this insulating rod 15 is connected to a positive terminal made of a thin stainless steel plate. The other open surface of the insulating frame 15 is closed with a negative electrode terminal plate (7) made of a thin stainless steel plate, and the positive electrode terminal plate 16 is brought into close contact with the positive electrode mixture sheet 12. The power generation unit) 11 is hermetically sealed with a thickness of 0.5
mm flat batteries have been developed.

In a flat organic solvent battery having such a structure, when placing the positive electrode mixture sheet 12 on the positive electrode terminal plate I6, titanium carbide, titanium carbide, Coating a conductive ceramic layer 18 such as nitride tinta has been used because it has superior battery discharge characteristics and storage characteristics.

(Problem to be Solved by the Invention) However, when forming the conductive ceramic layer on the positive electrode terminal plate, titanium carbide and titanium nitride powder were directly applied and formed, so the contact between the positive electrode mixture sheet and the positive electrode terminal plate was Although the resistance could be reduced, the ceramic powder on the positive terminal plate fell off and adhered to the sealing part of the insulating frame, resulting in short circuits and sealing failures.

For this purpose, conductive ceramic powder was dispersed in an alcoholic or aqueous solution containing a thickener such as polyacrylic acid, and this was applied onto the positive terminal plate to form a conductive ceramic layer, but the ceramic was not completely coated. When the thickener is increased to the point where it does not fall off, the contact resistance between the positive electrode mixture sheet and the positive terminal plate increases, causing problems such as deterioration of battery discharge characteristics.

An object of the present invention is to apply or drop a solution containing a nonionic surfactant in which at least one of titanium carbide and titanium nitride is dispersed between the contact surface of a positive electrode mixture sheet and a positive terminal plate to form a conductive ceramic material. By forming a layer, an organic solvent battery is provided in which the ceramic powder does not fall off and the contact resistance between the two can be reduced.

[Structure of the invention]

(Means for Solving the Problems) The present invention includes a power generation unit in which a positive electrode mixture sheet and a negative electrode sheet are stacked with a separator interposed therebetween, an annular insulating frame surrounding the periphery of the power generating unit, and an insulating frame. In a flat battery comprising a positive terminal plate that covers one opening surface and is in close contact with the positive electrode mixture sheet, and a negative electrode terminal plate that covers the other opening surface of the insulating frame and is in close contact with the negative electrode sheet. A nonionic surfactant-added solution in which at least one of titanium carbide or titanium nitride is dispersed is applied or dropped between the positive electrode terminal plate and the positive electrode mixture sheet to form and interpose a conductive ceramic layer. It is an organic solvent battery.

(Function) The present invention prevents ceramic powder from falling off by applying or dropping a solution containing a nonionic surfactant in which titanium carbide or titanium nitride is dispersed to form it on the inner surface of the positive terminal plate. It is possible to obtain an organic solvent battery that has no sealing defects and has reduced internal resistance.

(Point Example) FIG. 1 is a structural diagram of an example of a flat organic solvent battery of the present invention. In the figure, 1 is a power generation unit, and this power generation unit 1 is composed of a positive electrode mixture sheet 2 made of manganese dioxide, graphite, and polylatrafluoroethylene, and lithium perchlorate dissolved in propylene carbonate at a concentration of 1 moρ/g. A separator 3 made of a polypropylene nonwoven fabric impregnated with a non-aqueous electrolyte and a negative electrode sheet 4 made of metallic lithium are laminated in this order.

The periphery of this power generation unit 1 is surrounded by an annular insulating frame 5 made of modified polypropylene. Then, a positive electrode terminal plate 6 provided with a conductive ceramic layer 8 having a thickness of 10 μm is attached to one opening surface of the insulating frame 5.
is placed in contact with the positive electrode mixture sheet 2, and the negative electrode terminal plate 7 is placed in contact with the negative electrode sheet 4.
By thermally bonding the negative terminal plates 6, 7 and the insulating frame 5 at 200°C, the power generation unit 1 is sealed, and the thickness is 0.5 mm.
A flat battery with an outer diameter of 30 x 30 mm is formed.

The conductive ceramic layer 8 contains titanium carbide powder or titanium nitride powder. The titanium carbide powder is Tic-1 manufactured by Nihon Shinkinzoku ■, and has a particle size of 0.8 to 1.5.
The titanium nitride powder was TiN manufactured by Macro Co., Ltd. and had a particle size of 1.5 to 2.0 μm.

20 parts by weight of this conductive ceramic powder was dispersed in 80 parts by weight of Efnol containing 10 parts by weight of a polypropylene glycol ethylene oxide-added nonionic surfactant to form a paste. Coat the opposite side of the agent sheet 2 to a thickness of 10 ± 5 μm.
A conductive ceramic layer 8 was formed.

Table 1 shows the performance of the flat organic solvent battery of the present invention. Example 1 in the table is a flat battery using titanium carbide as the conductive ceramic powder, and Example 2 is a flat battery using nitrided conductive ceramic powder A total of 100 flat batteries were manufactured by dropping titanium on each battery.

In Comparative Example 1, 3 parts by weight of titanium carbide powder and 97 parts by weight of ethanol (3% by weight) were used as conductive ceramic powder.
The same flat type as the conventional one is made by dispersing the paste into a paste (containing polyacrylic acid) and applying this paste to the surface of the positive electrode terminal plate 16 facing the positive electrode mixture sheet 12 to form a conductive layer 18 with a thickness of 10±5 μm. It is an organic solvent battery. Furthermore, Comparative Example 2 is a flat organic solvent battery of the same type as Comparative Example 1 in which titanium nitride powder is used as the conductive ceramic powder.
．． A total of 100 conventional batteries were produced for each of the second conventional batteries.

Table 1 shows the impedance immediately after manufacture for each of 100 flat batteries manufactured under the above conditions, and the initial impedance of 1.5Ω.
Continuous sheet weight characteristics (2.5 V final voltage) and discharge capacity during 15Ω continuous discharge (2.5 V final voltage) after storage at 50° C. for 20 days are shown.

In addition, Example 3 of the present invention uses TiC/TiN solid solution powder as the conductive ceramic powder. In addition, in Comparative Examples 1 and 2, in which conductive ceramic powder was dispersed in ethanol, applied to the positive terminal plate, and dried, the powder fell off the positive terminal plate, contaminating the manufacturing process, and caused sealing defects and short circuits in the battery. .

The average particle size of the titanium carbide and titanium nitride powder used in the battery of the present invention is 0. A range of 1 to 5 μm is preferred. 0.1μ
If the average particle size is less than m, the influence of surface oxidation will appear, reducing the conductivity. On the other hand, if it exceeds 5 μm, the thickness of the conductive contact member formed on the terminal plate becomes thick, which is not preferable because it causes a decrease in the discharge capacity of the flat battery for this purpose.

Conductive ceramic powder is dispersed in a solution of a nonionic surfactant dissolved in water or an alcohol such as methanol or ethanol, and this paste is applied or dropped onto the surface of the positive electrode terminal plate that will be in contact with the positive electrode mixture sheet. put it into use. Note that the nonionic surfactant is preferably a polyethylene glycol type nonionic surfactant. Particularly preferred are higher alcohol ethylene oxide adducts, alkylphenol ethylene oxide adducts, fatty acid ethylene oxide adducts, and polypropylene glycol ethylene oxide adducts. If a paste is used in which conductive ceramics are dispersed in a solution containing the nonionic surfactant, the ceramic powder will not fall off even after coating and drying.

The conductive ceramic powder may contain at least one of titanium carbide and titanium nitride powder, and other conductive ceramics or high-purity graphite may be mixed therein.

Moreover, both TiC/TiN solid solution powder and mixed powder have some effects.

The thickness of the conductive ceramic layer is preferably 5 to 30 μm. If the thickness is less than 5 μm, contact with the positive electrode mixture sheet is insufficient. If it exceeds 30 μm, the volume occupied by the positive electrode mixture sheet will decrease, resulting in a significant decrease in discharge capacity.

In the titanium carbide powder and titanium nitride powder that are the mainstay of the present invention, performance deterioration due to an increase in internal resistance during battery storage due to impurities such as graphite has not been confirmed.

In addition, the specific conductivity of titanium carbide powder and titanium nitride powder is 1~
It is 10Ω-1cm-1 (green compact), suitable for electrical conductivity, and has excellent heat resistance and solvent resistance.

In addition, in the examples of the present invention, a polypropylene glycol ethylene oxide addition type was used as a nonionic surfactant, but polyethylene glycol type nonionic interfaces such as higher alcohol ethylene oxide adducts, alkylphenol ethylene oxide adducts, fatty acid ethylene oxide adducts, etc. Even when an activator is used, discharge characteristics equivalent to those of Examples 1 to 3 can be obtained.

Further, the present invention can also provide similar effects in a button type organic solvent battery.

〔Effect of the invention〕

As explained above, in the organic solvent battery of the present invention, a nonionic surfactant-added solution is applied or dropped as a dispersion medium to the contact surface between the positive electrode mixture sheet and the positive terminal plate to form a conductive ceramic layer. Therefore, a battery with excellent discharge performance and storage performance can be obtained.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of a first example of a flat organic solvent battery of the present invention, and FIG. 2 is a sectional view of a conventional comparative battery of the same type. 1... Power generation unit 2... Positive electrode mixture sheet 5... Insulating frame 6... Positive electrode terminal plate 8... Ceramic layer

Claims (1)

[Claims] In an organic solvent battery in which a positive electrode mixture sheet and a positive terminal plate are in contact with each other via a conductive ceramic layer, the conductive ceramic layer comprises a nonionic surfactant in which at least one of titanium carbide and titanium nitride is dispersed. An organic solvent battery characterized by being formed by coating or dropping an additive solution.