JPH0384851A - Manufacture of tubular lithium battery - Google Patents

Abstract

PURPOSE:To prevent airtightness in a hermetically sealed portion of a tubular lithium battery from being lowered so as to increase the filling effective volume of a mix within the battery by fabricating a battery can which contains mix and a metal ring, using a punch comprising a core portion and a sleeve, and a die. CONSTITUTION:A molding punch 10 includes a core portion 10a having a diameter phi1, equal to or a little smaller than the inner diameter phi2 of tubular metal lithium 2, i.e., a negative electrode mix, and a sleeve portion 10b having a diameter phi3 equal to or a little smaller than the inner diameter of the upper face of a metal ring 8 after molding. A molding die 11 has an inner diameter phi5 equal to or a little larger than the outer diameter phi6 of a battery can 1. The battery can 1 is passed through the die while being pressurized by a press and is fabricated so that the outer diameter phi7 of its large diameter portion 1a is equal to the outer diameter phi6 of the other portion of the battery can. Thus the L-shaped metal ring 8 is firmly fixed by an inward fastening force exerted by the large diameter portion 1a of the battery can 1 and the molding punch 10. Thus airtightness of the battery is enhanced and the filling effective volume of the mix is increased.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a method for manufacturing a cylindrical lithium battery that is used as a power source for small electronic devices related to electronics, and particularly as a battery for weak discharge such as memory backup. be.

Conventional technology Organic electrolyte batteries that use metallic lithium as the negative electrode have a high energy density, excellent storage properties, and a wide operating temperature range, making them ideal for memory backup with current consumption of only a few μA for batteries, meters, computers, etc. It is becoming more and more commonly used as a power source.

The structure of such a lithium battery is such that the positive electrode is a positive electrode mixture crimped onto a current collector, and the positive electrode and negative electrode are formed into a sheet and are spirally wound through a separator. There is a so-called jelly roll structure. In this case, there is a disadvantage that the volume occupied by the separator applied to the wound body increases, and the effective volume for filling the positive and negative electrodes in the housing decreases.

On the other hand, there are so-called inside-out types in which a positive electrode mixture is pressure-bonded to the inside of a battery can, and a cylindrical negative electrode is inserted into the hollow part of the positive electrode through a separator, or the positional relationship between the positive and negative electrodes. A bobbin-type structure with a reversed structure has a high capacity and a simple structure.

However, in these inside-out type and bobbin type configurations, the positive and negative electrode mixture acts as a consumable electrode during discharge and long-term storage, and the positive electrode absorbs electrolyte and becomes soft. As a result, the button was pressed in the sealing area, causing a decrease in airtightness.

Problems to be Solved by the Invention For this purpose, the construction as shown in FIG. It was necessary to pressurize the negative electrode mixture to prevent a decrease in airtightness in the sealed airtight part. Therefore, the effective filling volume of the positive or negative electrode mixture in the battery was inevitably reduced by 90 minutes for the metal ring.

Means to solve problems The present invention solves the above-mentioned problems.

1. First, make the outside diameter of the opening part of the battery can that the battery sealing part comes into contact with larger than the outside diameter of other parts, insert the cylindrical positive or negative electrode mixture, and then insert the positive or negative electrode mixture into the top surface of the positive or negative electrode mixture. A metal ring with an angular cross section is inserted into the large diameter part of the battery can. Thereafter, the positive or negative electrode mixture is pressurized into the battery can through the cross-shaped metal ring using a mold. For this purpose, a manufacturing method is adopted in which the large-diameter portion of the battery can is molded to have the same outer diameter as the other portions of the battery can.

By adopting a manufacturing method that exceeds the above, the metal ring is firmly fixed to the battery can by force when tightened in the inner diameter direction, improving airtightness. Further, since the volume of the metal ring is smaller than that of the conventional ring, the effective volume for filling the mixture can be increased.

Example Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a cylindrical lithium battery having a bobbin type structure manufactured by the manufacturing method of the present invention. Reference numeral 1 denotes a cylindrical battery can with a cylindrical metal lithium 2 crimped onto its inner surface. 3 is a positive electrode mixture, which is a mixture of a metal oxide such as manganese dioxide, graphite as a conductive material, and a binder, and molded into a cylindrical shape.

Reference numeral 4 denotes a bottomed cylindrical separator made of a polyolefin resin film or a nonwoven fabric, and encloses the positive electrode mixture 3. Reference numeral 5 denotes a positive electrode current collector made of carbon or SUS material, which is inserted and buried in the center of the positive electrode mixture 3, and its upper surface is electrically conductively fixed to the inner bottom surface of the sealing plate 6. . The sealing plate 6 is made of nickel-plated iron or SUS material. 7 is the sealing plate 6
This is an insulating packing that is fitted around the periphery of the battery to prevent leakage of the built-in electrolyte and to insulate the positive and negative electrodes, and is made of polyethylene and polypropylene.

8 is a metal ring with an angular cross section.

Next, the manufacturing method of the present invention will be explained with reference to FIGS. 2 and 3. FIG. 3 is a diagram showing the state at the time of manufacture of the present invention, 10 is a punch for molding, and the core has a diameter φ1 that is equal to or slightly smaller than the inner diameter φ2 of the cylindrical metal lithium 2 of the negative electrode mixture. It has a sleeve portion 10b whose diameter φ3 is equal to or slightly smaller than the inner diameter of the upper surface of the metal ring after molding. The core moves while contacting the sleeve, and enters the mixture while covering the metal ring with the sleeve. 11 is a molding die whose inner diameter φ5 is equal to or slightly larger than the outer diameter φ6 of the battery can 1; A metal ring 8 having an angular cross section with an outer diameter equal to or slightly smaller than the inner diameter of the large diameter portion 1a of the battery can 1 is arranged on the top surface of the metal lithium 2. Pass it through a die under pressure using a press, and form it so that the outer diameter φ7 of the large diameter portion 1a is equal to the outer diameter φ6 of the other part of the battery can, as shown in FIGS. 2A and B. do. Through this molding process, the L-shaped metal ring 8 is formed into the large-diameter portion 1a of the battery can 1 and the punch 10 for molding.
The inward tightening is firmly fixed by force.

! In addition, the cylindrical metal lithium 2, which is the negative electrode mixture, is placed on the bottom surface 8a of the L-shaped metal ring 8 and the punch 1 for molding.
0, it is crimped into a cylindrical shape on the inner surface of the battery can in a predetermined shape.

Next, a bottomed cylindrical separator 4 is placed on the inner peripheral surface of the cylindrical metal lithium 2 . Insert the positive electrode mixture 3.

Thereafter, an insulating packing 7 fitted to the peripheral edge of the sealing plate 6 having the current collector 5 provided in the center thereof is fitted to the inner circumferential surface of the above-mentioned cross-shaped metal ring 8. Finally, the opening of the battery can 1 is bent inward using a mold to airtightly seal the opening of the battery can 1.

Diameter 17.5ff, height 34.0ffil, capacity 170
Constructs a 0mAh cylindrical lithium manganese dioxide battery,
A discharge test was conducted with a load resistance of soKΩ. Table 1 shows the results of comparing the actual discharge capacity with that of the conventional configuration. Table 2 shows a discharge test with a load resistance of 3oKQ at a temperature of 86℃ and 7
The number of leakages from the battery was investigated when the test was carried out in an atmosphere of 0°C.

These are the results of 5 tests each. .

As shown in Table 1, the test shows that the device of the present invention has an increased discharge capacity of 18% to 29% compared to the conventional configuration, and is superior to the conventional configuration in terms of leakage resistance. It is superior to .

Effects of the Invention According to the present invention, a cylindrical battery having a large discharge capacity and excellent leakage resistance can be obtained.

[Brief explanation of drawings]

Fig. 1 is a longitudinal cross-sectional view of the main parts of a battery manufactured by the manufacturing method according to the present invention, Fig. 2 is a longitudinal cross-sectional view of the main parts of the battery according to the molding method according to the present invention, illustrating before and after molding, and Fig. 3 is a longitudinal cross-sectional view of the main parts of a battery according to the present invention. FIG. 4 is a schematic cross-sectional view illustrating the state during manufacture, and FIG. 4 is a longitudinal cross-sectional view of the main parts of a battery manufactured by a conventional manufacturing method. 1...Battery can, 1a...Large diameter part, 2.
...Negative electrode mixture, 3...Positive electrode mixture, 4...
...Separator, 5...Current collector, 6...
...Sealing plate, completed...Insulation paved:) King. 8...1-shaped metal ring, 10...punch type, 10a...core, 10b...
Sleeve, 11...Dice type.

Claims (1)

[Claims] Insulating the opening of the battery can containing the power generation element 7
In the manufacturing method of a cylindrical battery in which the battery is sealed with a sealing plate 6 through A step of disposing a metal ring having an L-shaped cross section in the opening of the metal ring, and having a core portion 10a that is equal to or slightly smaller than the inner diameter of the cylindrical mixture, and after molding, the inner diameter of the upper surface of the metal ring is The mixture and the metal ring are prepared by using a punch die 10 comprising a sleeve 10b having an outer diameter equal to or slightly smaller than the outer diameter of the battery can, and a die die 11 having an inner diameter equal to or slightly smaller than the outer diameter of the battery can. a step of molding a battery can containing the battery can, and a step of pressurizing the enlarged diameter opening of the battery can inward to make the opening of the battery can equal to the outer diameter of the other part of the battery can. A method for manufacturing a cylindrical battery characterized by the following.