JPH08222192A - Battery - Google Patents

Abstract

PURPOSE: To provide a battery having a high capacity and excellent leakage resistance by providing no folded portion on the peripheral edge of a negative electrode cap, and making the radius of curvature of the tip portion of the negative electrode cap smaller than that of the outer periphery side portion. CONSTITUTION: Silver oxide and graphite serving as a conductive auxiliary are mixed at the weight ratio of 100:10, for example, to form a positive electrode mix, and it is pressurized and molded into a disk shape to form a positive electrode 1. A gelatinizer and an electrolyte are mixed with zinc serving as an active material into a paste to form a negative electrode 2. No folded portion is provided on the peripheral edge 5a of a negative electrode cap 5, and the radius of curvature of the inner periphery side portion 5b of the tip is set to 0.04mm, which is smaller than the radius of curvature of the outer periphery side portion 5c set to 0.25mm. Since no folded portion is provided on the peripheral edge of the negative electrode cap 5 of this battery, the internal volume is larger than that of the conventional battery, and the leakage resistance is better than that of the battery having the radius of curvature of the inner periphery side portion larger than that of the outer periphery side portion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat type battery called a button type battery or a coin type battery, which is used for a positive electrode can having a flat longitudinal section, and more particularly to a flat type battery having a high capacity and a leakage resistance. It relates to a battery having excellent properties.

[0002]

2. Description of the Related Art In recent years, with the development of electronic devices, portable devices have been further miniaturized.
A battery having a diameter of 5 mm or less and a thickness of 2 mm or less is mounted. However, in the battery container, the smaller the battery is, the larger the ratio in the entire battery is, which hinders the increase in the capacity of the battery.

The conventional battery will be described below.
Conventionally, a structure as shown in FIG. 3 has been adopted.

That is, the negative electrode cap 5 is provided with a folded-back portion 5d on the peripheral portion 5a (see, for example, Japanese Patent Laid-Open No. 57-57).
No. 154768). If such a structure is adopted, the reliability of the sealing is improved, but on the other hand, since the volume occupied by the sealing portion is large, the internal volume of the battery becomes small,
There is a problem that the capacity becomes small and the high capacity cannot be achieved.

Therefore, as shown in FIG. 4, the folded portion is not provided on the peripheral portion 5a of the negative electrode cap 5,
Attempts have been made to increase the capacity by reducing the volume occupied by the sealing portion and increasing the internal volume of the battery (for example, Japanese Patent Laid-Open No. 63-281368), but the negative electrode cap as shown in FIG. 5 has a folded-back portion 5d on the peripheral portion 5a.
There is a problem that the liquid leakage resistance is inferior to the battery having the structure provided with.

[0006]

SUMMARY OF THE INVENTION According to the present invention, the ratio of the volume occupied by the sealing portion to the volume of the entire battery possessed by the conventional battery is large, and as a result, the internal volume of the battery is reduced and the capacity is reduced. It is an object of the present invention to provide a battery having a high capacity and an excellent leakage resistance by solving the problem that the battery has a small size, and a proposal to solve the problem also causes a decrease in the leakage resistance.

[0007]

The structure of the present invention for solving the above problems will be described with reference to FIGS. 1 and 2 corresponding to the embodiment.
The object described above is achieved by not providing a folded portion in a and making the radius of curvature of the inner peripheral side portion 5b at the tip of the peripheral edge portion 5a of the negative electrode cap 5 smaller than the radius of curvature of the outer peripheral side portion 5c.

That is, the folded portion is not provided on the peripheral edge portion 5a of the negative electrode cap 5, the internal volume of the battery is increased, the capacity is increased, and the tip of the peripheral edge portion 5a of the negative electrode cap 5 is increased. By making the radius of curvature of the peripheral side portion 5b smaller than the radius of curvature of the outer peripheral side portion 5c, the opening end of the positive electrode can 4 is tightened inward at the time of sealing, so that the tip of the peripheral edge portion 5a of the negative electrode cap 5 and the annular shape. The tightness with the packing 6 is increased, and thereby the liquid leakage resistance is improved.

[0009]

Embodiments of the present invention will now be described with reference to the drawings. However, the present invention is not limited to the examples illustrated in the embodiments, and the materials and the like of the respective constituent members are not limited to those illustrated in the examples.

FIG. 1 is a vertical sectional view showing an embodiment of the battery of the present invention, and FIG. 2 is an enlarged view of a main part of FIG.

In the figure, 1 is a positive electrode, 2 is a negative electrode, 3 is a separator, and this separator 3 separates the positive electrode 1 and the negative electrode 2 from each other. Reference numeral 4 denotes a positive electrode can. The positive electrode can 4 has a flat vertical cross-section and a diameter larger than the depth. Reference numeral 5 denotes a negative electrode cap, and a peripheral portion 5a of the negative electrode cap 5 has no folded portion. 6
Is an annular packing.

The radius of curvature of the inner peripheral portion 5b at the tip of the peripheral edge portion 5a of the negative electrode cap 5 is smaller than the radius of curvature of the outer peripheral portion 5c, and the radius of curvature of the inner peripheral portion 5b is 0.01.
.About.0.06 mm is preferable, and the radius of curvature of the outer peripheral side portion 5c is preferably 0.1 to 0.3 mm.

Next, in the button type silver oxide battery having an outer diameter of 9.5 mm and a height of 2 mm, the discharge capacity and the leakage resistance of the battery A of the present invention and the batteries B and C of the present invention are shown. .

First, the material of each constituent member of the battery will be explained. The material is the same for all batteries A, B and C, and the positive electrode 1 contains silver oxide (Ag ₂ O) and graphite as a conductive auxiliary agent by weight. A positive electrode mixture prepared by mixing at a ratio of 100: 10 was pressure-molded into a disk shape, and the negative electrode 2 was made of zinc as an active material and was mixed with a gelling agent and an electrolytic solution in a paste form. It is a thing.

The separator 3 is formed by stacking a microporous polypropylene film, cellophane and vinylon-rayon mixed paper, and has a total thickness of 0.2 mm. The electrolytic solution is a 35 wt% potassium hydroxide aqueous solution saturated with zinc oxide. It will be.

The positive electrode can 4 is made of iron having a thickness of 0.25 mm, and the surface thereof is nickel-plated. The negative electrode cap 5 is made of a three-layer clad plate having a thickness of 0.22 mm of nickel layer / stainless steel plate / copper layer. , The copper layer is arranged inside the battery. The annular packing 6 is made of nylon 66.

The battery A of the present invention has the structure shown in FIGS. 1 and 2, in which the peripheral edge portion 5a of the negative electrode cap 5 is not provided with a folded-back portion, and the radius of curvature of the inner peripheral side portion 5b at its tip is 0.04 mm, the radius of curvature of the outer peripheral portion 5c is 0.2
The radius of curvature of the inner peripheral side portion 5b is smaller than that of the outer peripheral side portion 5c.

In the battery A of the present invention, since the peripheral portion 5a of the negative electrode cap 5 is not provided with the folded-back portion as described above, the internal volume of the battery is larger than that of the conventional battery, and the positive electrode 1 The diameter is 8.6 mm, and the amount of zinc in the negative electrode 2 is 60 mg.

The battery B outside the present invention is, as shown in FIG.
It has a conventional structure, and the peripheral portion 5 of the negative electrode cap 5 is formed.
A folded portion 5d is provided at a. As a result, in this battery B, the positive electrode 1 had a diameter of 7.3 mm and the negative electrode 2 had a zinc content of 45 mg.

The battery C has the structure shown in FIG. 4, and the folded portion is not provided on the peripheral edge portion 5a of the negative electrode cap 5, but the inner peripheral portion 5b at the tip of the peripheral edge portion 5a of the negative electrode cap 5 is formed. Has a radius of curvature of 0.25 mm, and the outer peripheral side portion 5c has a radius of curvature of 0.04 mm.
The radius of curvature of b is larger than the radius of curvature of the outer peripheral side portion 5c.

In this battery C, the negative electrode cap 5
Since there is no folded portion on the peripheral edge 5a of the
The internal volume is larger than that of the battery B, and similarly to the battery A of the present invention, the positive electrode 1 has a diameter of 8.6 mm and the negative electrode 2 has a zinc content of 60 mg.

The above batteries A, B and C were placed at 20 ° C. and 15 k
The discharge capacity was measured by continuously discharging at Ω. Table 1 shows the results.

However, Table 1 shows the discharge capacity of the battery A of the present invention as an index. The discharge capacity of the battery A of the present invention is 50 mAh.

The above batteries A, B and C are each 100
Each was stored for 60 days in an atmosphere of 60 ° C. and a relative humidity of 90%, and the presence or absence of liquid leakage was examined. The results are shown in Table 1 by the leakage rate.

[0025]

[Table 1]

As shown in Table 1, the battery A of the present invention had a larger discharge capacity than the battery B of the conventional structure, and the liquid leakage resistance was superior to the battery C of the present invention.

That is, although the battery B having the conventional structure has excellent leakage resistance, it has a small discharge capacity, and the battery C other than the present invention has a large discharge capacity, but has poor leakage resistance.

Although the silver oxide battery was described in Example 1, the present invention can be applied to any type of active material, and a battery using an aqueous electrolyte solution or a non-aqueous electrolyte can be used. The present invention can be applied to any type of electrolyte such as a battery using a liquid, and in any case, high capacity can be achieved and liquid leakage resistance can be kept good.

[0029]

As described above, according to the present invention, the peripheral portion of the negative electrode cap is not provided with a folded portion, and the radius of curvature of the inner peripheral side portion of the tip of the negative electrode cap is made smaller than the radius of curvature of the outer peripheral side portion. As a result, it was possible to provide a battery having high capacity and excellent liquid leakage resistance.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a battery of the present invention.

FIG. 2 is an enlarged view of a main part of the battery shown in FIG.

FIG. 3 is a vertical sectional view of a conventional battery.

FIG. 4 is a vertical cross-sectional view of a battery having a configuration different from that of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Positive electrode 2 Negative electrode 3 Separator 4 Positive electrode can 5 Negative electrode cap 5a Peripheral part 5b Inner peripheral part 5c Outer peripheral part 6 Annular packing

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Osamu Okamoto 1-88 1-Tora Tora, Ibaraki City, Osaka Prefecture Hitachi Maxell Co., Ltd.

Claims (1)

[Claims] 1. A positive electrode can (4) having a flat longitudinal section and a negative electrode cap (5) containing a positive electrode (1), a negative electrode (2), an electrolytic solution and a separator (3) in an annular packing (6). ), The battery having a structure constituted by crimping and sealing the negative electrode cap (5) does not have a folded-back portion on the peripheral edge portion (5a), and the tip of the peripheral edge portion (5a) of the negative electrode cap (5) is not provided. A battery having a radius of curvature of an inner peripheral side portion (5b) smaller than that of an outer peripheral side portion (5c).