JPS5882465A - Manufacture of alkaline battery - Google Patents

Abstract

PURPOSE:To prevent a winding core from breaking a separator bottom part through owing to the friction between an inside wall of the positive pole black mix and the separator as well as to improve manufacturing process of a battery and quality thereof by adding the process, wherein the part of a lower part of separator base paper, which is to bend inwardly, is moisted with water or a water solution of polyvinyl alcohol for getting a habit thereto. CONSTITUTION:A polyvinylalcohol binder in unwoven cloth is dissolved by means water as a solvent by being given water to the lower part of the wound separator base paper and further by the phenomena such as the evaporation of a solvent by the pressure and heat given by a metal mold 10 together with solidification of polyvinylalcohol accompanying thereto, the part to be bent inwardly gets habit thereto. Next, the separator lower end part 2a thus bent is give firm adheyence while being melted through the heated metal mold 11 to assume the stabilized shape of a bottomed cylinder. Accordingly the formation of the separator bottom part is firm so as to get stabilization at the time of mechanical assembly. The same effect can also be gained by using a water solution of polyvinyl-alcohol in place of water.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a cylindrical alkaline battery, and aims to improve the manufacturing process and quality of the battery.

Conventionally, the manufacturing method for this type of battery separator is as follows:
A separator base paper made of synthetic paper such as vinylon is cut into rectangular shapes of a certain size, and a winding core is used to rotate the cut separator base paper, and a winding guide that faces the winding core and has an arc-shaped notch in a part. The lower end of the rolled separator base paper is brought into contact with a mold having a special shape, and the separator base paper is inserted in between and rolled into multiple layers in a cylindrical shape using a winding core. A method was adopted in which the separator was bent to form a cylindrical separator with a bottom.

However, this method has the following drawbacks.

In other words, when forming the separator bottom, the lower end of the separator is bent inward using a mold with a special shape, thereby suppressing the unfolding and restoring properties of the separator bottom, resulting in mechanical timing discrepancies, etc. This may cause variations in the suppression of the bottom part, and when the separator is inserted into the positive electrode mixture hollow part in the next process, it may be caused by friction between the inner wall of the positive electrode gap and the separator.
The winding core sometimes broke through the bottom of the separator, causing problems in machine operation.

In addition, in such a battery, after the battery is constructed, the positive electrode mixture powder and the gelled negative electrode tend to migrate to the counter electrode, causing an internal short circuit.

The present invention relates to a method for manufacturing an alkaline battery that eliminates the above-mentioned conventional drawbacks, and will be described in detail below with reference to Examples.

Fig. 1 is an explanatory diagram of cutting a roll-wound band separator to a predetermined length and then winding it into a cylindrical shape. In the figure, 1 is a woven or non-woven fabric made of synthetic fibers such as vinylon with polyvinyl alcohol as a binder. This is a separator base paper, which is stacked in two layers to form separator 2. This separator 2 has a plurality of vertical lines 4 formed therein at regular intervals by a roller 3, and is then fed by a feed roller 5 and cut into rectangular pieces of a predetermined length by a rotary cutter 6. After this, the winding core 7 is inserted between the winding core 7 and a winding guide 8 which faces the winding core and has a circular arc notch in a portion thereof, and is wound in a multilayered state by the winding core. The lower end portion 2 of the separator shown in FIG. 2A is wound in multiple layers around the winding core 7.
A is in contact with the periphery of the disc-shaped felt 9 containing water as shown in the opening of Figure 2, and 5 to 10 mg of water is applied to 3 to 4 mm of the lower end, and the mold has a special shape as shown in c. 10 and performs a rotational circumferential movement, it is sequentially bent inward and shaped into a bottomed shape. Furthermore, this bent bottom part is brought into contact with a heating mold 11 kept at a temperature of 360° C. as shown in FIG. It is inserted into the hollow part of the positive electrode mixture 13 (FIG. 2). In the next step, the disc-shaped bottom paper 14 is drawn into a tap shape using a hollow drawing die and inserted into the inner bottom of the -C separator to form a complete bottomed 1-ring-shaped separator. Next, a gel-like negative electrode 16 mainly made of lead is filled into the separator, the positive electrode case 12 is closed with a gasket 18 having a negative electrode bottom plate 16 and a current collector 17, and a positive electrode terminal 19 is placed at the outer bottom of the positive electrode case.
are brought into contact with each other, covered with a heat-shrinkable resin tube 2o, insulating rings 21 are placed on both the upper and lower ends, and the outer end 22 is sealed to complete a cylindrical alkaline battery.

By applying water to the lower end of the separator base paper wound in this manner, the polyvinyl alcohol binder in the nonwoven fabric is dissolved in water as a solvent, and furthermore, by applying pressure and heat by the mold 10, the polyvinyl alcohol binder is dissolved in the solvent. Due to the phenomenon of evaporation of polyvinyl alcohol and the accompanying assimilation of polyvinyl alcohol, the inwardly bent portions become curly. Next, the folded lower end portion 2a of the separator is firmly fused by a heating mold 11 to form a stable bottomed cylindrical shape.

Therefore, since the formation of the separator bottom is strong, the above-described break-through of the separator bottom by the winding core when inserting the separator into the positive electrode mixture hollow part can be eliminated, and stability during mechanical assembly can be achieved.

Further, the same effect can be obtained by using an aqueous solution of polyvinyl alcohol instead of water. Here, the strength of the separator bottom depends on the amount of heat required to evaporate water, which is a solvent, ie, the product of the heating mold temperature and the time in contact with it, and the amount of solvent. Furthermore, by moistening the folded portion with water or a polyvinyl alcohol/aqueous solution, the so-called "stiffness" of the paper itself is weakened, making it easier to bend the paper inward.

Table 1 shows the number of cases in which the bottom of the separator was pierced by the winding core when the separator was inserted into the positive electrode mixture hollow part in the separator according to the present invention and the separator CB according to the conventional method.

In addition, Table 2 shows the electrical characteristics of a battery according to the present invention [A] and a battery using a conventional method using a separator (B) manufactured under JIS name LR6 (the samples are for each type). 60 pieces').

Table 1 Table 2 As shown in Table 1, in the separator made by the conventional method, the bottom of the separator often breaks through, and as is clear from Table 2, the battery made by the method of the present invention and the battery using the conventional separator It can be seen that they have the same characteristics. In this manner, the present invention can supply batteries with stable quality.

[Brief explanation of drawings]

Figure 1 is a perspective view of the process from transporting and cutting the separator base paper to winding it into a cylindrical shape. 1 is a half-cut sectional view of a battery according to the present invention. 1... Separator base paper, 2... Senokureta made by stacking two layers of separator base paper, 3...
The reinforcing material is a roller, 4... vertical strip, 6... mono to a predetermined length; a rotary cutter for cutting the lathe, 7...
... Winding core, 8... Winding guide, 9.
... Disc-shaped felt containing water, 10...
・Mold, 11...Heating mold, 12...
Positive electrode case, 13... Anode mixture, 14...
... Dish-shaped bottom paper, 15 ... Gel cathode, 18 ...
...Sealing gasket 0 Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
figure

Claims (1)

[Claims] The process of cutting separator base paper made of synthetic fiber nonwoven fabric using polyvinyl alcohol as a binder into squares, winding the cut separator base paper in a multilayer state, and folding the lower end of the separator base paper inward. a process of moistening and shaping with water or an aqueous polyvinyl alcohol solution, a process of sealing the lower end of the shaped separator 6 with a heated mold to form a bottomed cylindrical separator, and a step of forming a cylindrical positive electrode. A method for producing an alkaline battery, comprising the steps of inserting the bottomed cylindrical separator into the hollow part of the agent, and then filling the separator with a gelled negative electrode.