JPS58106767A - Manufacture of button-type alkaline battery - Google Patents

Abstract

PURPOSE:To increase the weighing accuracy of an amalgamated zinc, and prevent any scattering of sodium polyacrylate, which might be caused when electrolyte is poured during battery assembly, by forming sodium polyacrylate into a sheet before it is inserted into a negative can. CONSTITUTION:After a weighed amount of an amalgamated zinc powder 3 is packed into a negative can 2, an electrolyte 4 is poured into the can 2, and a weighed amount of a sodium polyacrylate sheet 5 is inserted into the negative can 2. On the other hand, after a positive mixture 8 is inserted into a positive can 7, a separator 9 and an electrolyte-absorbing body 8 are placed over the mixture 8. After that, the positive can 7 is reversed and attached to the negative can 2 so as to seal the battery, thereby constituting a button-type alkaline battery. At this point, the sheet 5 dissolves into the electrolyte 4, and is mixed with the amalgamated zinc 3 to form a negative agent 6. By the means mentioned above, the variation of the weighed values of the above sodium polyacrylate 5 and the above amalgamated zinc 3 is reduced, and the performance of the battery is improved.

Description

[Detailed Description of the Invention] The present invention relates to a method for manufacturing a button-type alkaline battery. is being done a lot.

However, because the difference in specificity between sodium polyacrylate and glazed zinc is large, it is difficult to obtain a homogeneous mixture of glazed zinc powder and sodium polyacrylate. Not only do the ratios vary, causing fluctuations in the active material's optical properties, but also the sodium polyacrylate absorbs moisture, making it difficult to measure accurately.
The weight A1 itself also begins to fluctuate.

Therefore, it may be possible to weigh both separately, but although this improves the accuracy of weighing frozen zinc, it is not always recommended because the sodium polyacrylate may scatter due to static electricity and the sodium polyacrylate may absorb water. This is not desirable〇Also, as long as powdered sodium polyacrylate is used for polishing, when the negative electrode can is filled and electrolyte is injected from above, the sodium polyacrylate will be exposed to the outside due to the pressure at the time of injection. This problem caused by sodium polyacrylate scattering to the outside when the electrolyte is injected becomes more obvious as the battery becomes thinner, and becomes a major hindrance when manufacturing thinner batteries. Become.

This book was created in view of such circumstances.
By forming a sheet of sodium polyacrylate, punching it out, and inserting it into the negative electrode can, the accuracy of weighing the sodium polyacrylate and zinc oxide is increased, and the scattering of the sodium polyacrylate sheet is prevented when the electrolyte is injected. It is.

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

A negative electrode can (2) with an annular gasket (1) fitted to the folded edge part is filled with frozen zinc powder (3), then an electrolyte (4) is injected, and then sodium polyacrylate (
Insert a sheet (5) of cross-linked sodium polyacrylate (see Figure 1) Separately, insert a positive electrode mixture (8) containing manganese dioxide as an active material into the positive electrode can (7), and - The product of the Kfl porous polypropylene film and cellophane layer on the positive electrode mixture (8)
A separator (9) made of MLFf and an electrolyte absorber (7) made of vinylon-rayon mixed paper are placed thereon, and the positive electrode can (7) in this state is turned upside down to form the negative electrode can (2) K. Once fitted, the opening peripheral wall of the positive electrode can (7) is tightened inward and curved, and its inner peripheral surface is covered with an annular gasket (1).
A stain pond was manufactured by press-fitting and sealing the battery.0 Figure 2 shows a cross section of the battery manufactured as described above.
0 However, in FIG. 2, which is shown upside down from the manufacturing process, (6) means that the sodium polyacrylate sheet (5) is dissolved in the electrolytic solution (4) K,
It is a negative electrode material formed by mixing with zinc hydrate (3).

Note that (b) is a stainless steel annular pedestal fixed to the peripheral edge of the positive electrode mixture (8) during pressure molding of the positive electrode mixture (8).

In the present invention, the sodium polyacrylate sheet is preferably inserted into the negative electrode can after filling the electrolyte as described above, but is not limited to this case. After that, the electrolyte may be injected, or the sodium polyacrylate sheet inserted into the negative electrode can may be inserted before filling with frozen zinc. Because it mixes with zinc chloride,
Compared to when it is mixed with zinc hydride in powder form, there is no particular deterioration in electrical performance. The addition cap for sodium polyacrylate may be about 0.5 to 5 parts per 100 parts (parts by weight, hereinafter the same) of zinc hydride, as in the case of using a powdered product.

The following Table 1 shows a comparison of the weighing accuracy between the case of weighing according to the present invention and the case of weighing according to the conventional method.

In the case of the present invention, only zinc hydrate powder is weighed, and in the case of the conventional method, a mixed powder in which 1 part of sodium polyacrylate powder is added to 100 parts of frozen zinc powder is weighed. Table 1 As shown in Table 1, in the method of the present invention, only the frozen zinc is weighed as a powder, so the weighing value is less uneven. According to the method of the present invention, sodium polyacrylate is weighed in the form of a sheet, so there is very little variation in the weighed values, and of course there is no scattering of sodium polyacrylate when the electrolyte is injected.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view schematically showing a state in which a shibori sodium acrylate sheet is inserted into a negative electrode can by the method of the present invention;
FIG. 2 is a sectional view of a button-type alkaline battery manufactured by the method of the present invention. (2)...Anode can, (5)...Sodium polyacrylate sheet Patent applicant: Hitachi Maxell, Ltd.

Claims (1)

[Claims] 1. A method for producing a button-type alkaline battery, which comprises inserting a sheet of sodium polyacrylate as a gelling agent into a negative electrode can.