JPS5954171A - Thin sealed storage battery - Google Patents

Abstract

PURPOSE:To enhance the liquid leakage resistance of a thin sealed storage battary by sealing the contact areas of each terminal lug and a case by means of an adhesive having rubber elasticity, and caulking said contact areas by means of a cylindrical metallic ring. CONSTITUTION:A positive terminal lug 5 and a negative terminal lug 6, respectively, are led outside from a positive and a negative plate 1 and 2 through the opening 7 of a case 4. The led out part 8 of each of the terminal lugs 5 and 6 is surrounded by the convex section of the case 4, the contact areas of the led out part 8 and the case 4 are sealed with an adhesive 9 and the convex sections are caulked with cylindrical metallic rings 10. In addition, the areas of the opening 7 other than the led out parts 8 are airtightly sealed through fusion by use of a heater, ultrasonic wave, laser or the like. As the adhesive 9 used to seal the spaces formed between the terminal lugs 5 and 6 and the case, 4 an electrolyte resistant material having rubber elasticity, for example, a synthetic rubber such as butyl rubber, nitrile rubber or butadiene-styrene rubber, an epoxy system adhesive or the like is employed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a thin sealed storage battery, and more particularly to a thin sealed storage battery that has excellent leakage resistance and a long service life.

[Prior art and its problems]

Generally, lead-acid batteries and alkaline batteries are often used as assembled batteries by connecting a plurality of single cells in series. In this case, when a plurality of cylindrical single cells are connected and housed in an outer container, there is a large amount of unfilled space in the container, and the volumetric efficiency of the storage battery as a whole becomes low. On the other hand, an assembled battery containing rectangular single cells has a high volumetric efficiency, and therefore can have a large discharge capacity.

However, even when prismatic cells are stored, as the assembled battery becomes smaller, the ratio of ineffective volume occupied by the cell container, partition plate, space for connecting the electrode plates, etc. increases, resulting in a decrease in volumetric efficiency. do.

Particularly when trying to obtain a small and thin assembled battery, the volumetric efficiency will drop significantly, making the production practically meaningless.

In order to solve these problems, sheets or plates of polymeric resin material are laminated with a separator containing an electrolyte in a bag-like container sealed by heat-sealing or gluing the periphery of the sheet or plate. A power generation element consisting of an anode plate and a cathode plate is housed,
A rectangular seal having a structure in which the electrode plate acts as a washer and the sheet or plate acts as an armrest to airtightly and liquid-tightly seal the opening of the bag-like container, and positive and negative terminals are arranged on the sides. A type battery has been proposed (Japanese Unexamined Patent Publication No. 14338/1983).

(See Japanese Patent Application Laid-open No. 14339/1983).

This type of battery does not require a strict and robust outer container or a complicated sealing mechanism, so the overall shape of the battery can be made thin and compact, making it possible to construct an assembled battery with high volumetric efficiency. can.

However, in order to lead out the terminal from the opening of the bag-like container and seal the terminal properly, the alkaline solution that is the electrolyte in the container must penetrate into the finer details. Due to its strong nature, force is required to press it strongly.

In this case, since the bag-like container is made of a polymer resin with low mechanical strength, this pressing force may cause damage.
In the end, this tends to lead to leakage of electrolyte from the battery.

Other methods for sealing the opening of the container include methods using various adhesives, but they generally have insufficient adhesion and are difficult to seal for a long time. As an exception, hot melt adhesives exhibit strong adhesion and provide good leakage resistance.

However, it has the disadvantage that leakage resistance decreases when used at high temperatures and large currents.

[Purpose of the invention]

The present invention provides a thin sealed storage battery that has excellent leakage resistance even when used at high temperatures and large currents and has a long service life by improving the drawbacks of the above-described method of sealing the opening. The purpose is to

[Summary of the invention]

In the thin sealed storage battery of the present invention, a power generation element consisting of an anode plate and a cathode plate stacked closely together via a separator containing an electrolytic solution is housed in a thermoplastic resin bag-like container. In a thin sealed storage battery, the terminal ears of the anode plate and the cathode plate are guided out of the container through an opening of the container, and the opening is sealed. The lead-out portion of the terminal ear portion is formed in a convex shape of the container, and the contact portion between the terminal ear portion and the container is sealed with an electrolyte-resistant adhesive having rubber elasticity. The container is characterized in that the convex portion of the container is caulked with a metal cylindrical ring, and the portions where the terminal ears and the container come into contact are sealed by heat sealing.

The thin sealed storage battery of the present invention will be explained with reference to the examples shown in FIGS. 1, 2, and 3. FIG. 1 is a partially cutaway view, and FIG. 2 is a longitudinal cross-sectional view taken along line AA' in FIG. FIG. 3 is an enlarged view of the metal cylindrical ring before caulking, with (a) being a front view and (b) being a side view.

In the figure, 1 is an anode plate, 2 is a cathode plate, and both are closely laminated with a separator 3 containing an electrolyte in between to form a power generation element as a whole.

This power generation element is housed in a bag-like container 4.

The container 4 is made of a tube, sheet, or plate (usually with a thickness of 0.1 to 0.1 mm) made of electrolyte-resistant and electrically insulating thermoplastic resin such as polyethylene, polyzorogylene, polyamide, polyvinyl chloride, fluororesin, and ABS resin. It is a rectangular bag made of 1.0 wg).

Reference numerals 5 and 6 denote an anode terminal ear and a cathode terminal ear, which are led out from the anode plate 1 and the cathode plate 2 through the opening 7 of the container 4, respectively. The lead-out portions 8 of the terminal ears 5 and 6 are formed in the container 4 in a convex shape, and the abutting portions are covered with adhesive 9.
The convex portion is caulked with a metal cylindrical ring 10. Further, the opening 7 other than the lead-out portion 8 is hermetically sealed by thermal fusion using means such as a heater, ultrasonic waves, or laser.

The adhesive 9 that seals the gaps (contact points) between the terminal ears 5 and 6 and the container 4 is made of an electrolyte-resistant material with rubber elasticity, and is airtight and liquid-resistant for both. Must be tightly bonded. Examples of such materials include, for example, comb-based adhesives and epoxy resins whose main components are synthetic rubbers such as butyl rubber, nitrile rubber, butadiene-styrene rubber, chloroprene rubber, urethane rubber, or copolymers containing these synthetic rubbers. Examples include adhesives.

The metal cylinder ff1lo for caulking the lead-out portion 8 preferably has an obtuse angle at its abutting portions 12 with the container 4 at both ends 11, and more preferably from 120 to 150 degrees. The material may be any metal that is plastically deformed by caulking and has the effect of squeezing the lead-out portion 8, such as copper, aluminum, iron, nickel, and alloys containing these metals as base materials. ! Furthermore, if necessary, these may be subjected to plating treatment.

The ratio of the length to the outer diameter of the metal cylindrical ring 10, that is, the length/
The outer diameter is preferably within the range of 0.2 to 0.8.

That is, if the ratio is less than 0.2, a sufficient caulking effect cannot be obtained, and the container 4 may be damaged, and even if the ratio is 0.8 or more, no further increase in the caulking effect can be obtained.
This is because, on the contrary, it reduces the volumetric efficiency of the battery.

[Embodiments of the invention]

Next, the present invention will be explained in more detail with reference to Examples, but the following Examples are not intended to limit the scope of the present invention in any way.

Nickel electrode as anode plate, cadmium electrode as cathode plate, polypropylene nonwoven fabric as separator, potassium hydroxide aqueous solution as electrolyte, thickness 0.15 as container
A thin sealed nickel-cadmium storage battery having the structure shown in FIGS. 1 and 2 was manufactured using a polyethylene sheet having a thickness of 1 mm.

The battery dimensions were 85 mm in forward direction, 65 mm in short side, and 4 mm in thickness. The terminal ears 5 and 6 were made of nickel plates with a width of 5 mm, and the lead-out portion 8 was sealed with a butyl synthetic rubber adhesive 9. Furthermore, the outer diameter is 10y+m, the length is 4mm, and the angle of the contact point 12 with the container 4 is 135° (Example 1) or 90° (
The lead-out portion 8 was caulked by the copper metal cylindrical ring 10 of Example 2).

For comparison, a battery (comparative example) was prepared in the same manner as above, except that the metal cylinder 3i110 was not used and crimping was not performed.

For each of the above 20 battery cans, the battery voltage is 1 at a discharge rate of 1c.
．． A charging/discharging cycle of discharging until Ov and then charging completely was repeated, and the leakage rate and discharge capacity maintenance rate at that time were measured. The results are shown in the table.

Table [Effects of the Invention] As is clear from the above results, the battery of the present invention has excellent leakage resistance, and therefore has a high discharge capacity retention rate and a long service life. This is because the contact area between the terminal ear and the container is sealed with a rubber-elastic adhesive and caulked with a metal cylindrical ring, so the sealed opening is protected from external mechanical damage. This is because it exhibits sufficient resistance to distortion and impact, and maintains a sealing effect over a long period of time.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway view showing an embodiment of a thin sealed storage battery according to the present invention, and FIG. 2 is a longitudinal cross-sectional view taken along line AA' in FIG. 1. FIG. 3 is an enlarged view of the metal cylindrical ring before caulking, where (a) is a front view and (b) is a side view. DESCRIPTION OF SYMBOLS 1... Anode plate, 2... Cathode plate, 3... Senorator, 4... Container, 5... Anode terminal ear part, 6... Cathode terminal ear part, 7... Opening portion, 8... Leading out portion, 9...
・Adhesive, 1o...metal cylindrical ring, 11...both ends,
12... Points of contact with the container at both ends.

Claims (1)

[Claims] 1. A power generation element consisting of an anode plate and a cathode plate stacked closely together via a center plate containing an electrolyte,
A structure in which the device is housed in a bag-like container made of thermoplastic resin, the terminal ears of the anode plate and the cathode plate are guided out of the container through an opening of the container, and the opening is sealed. In the thin sealed storage battery, the container is formed in a convex shape at the lead-out portion of the terminal ear, and the abutment area between the terminal ear and the container is covered with an electrolytic-resistant material having elasticity. In addition to sealing with a liquid adhesive, the convex portion of the container is caulked with a metal cylindrical ring, and
The thin sealed storage battery has a structure in which the portions where the terminal ears and the container do not come into contact are sealed by heat-sealing. 2. The thin sealed storage battery according to claim 1, wherein the angles of the portions of both ends of the metal cylindrical ring that contact the container are obtuse angles.