JPS6366029B2 - - Google Patents

Description

[Detailed description of the invention]

This invention relates to an improvement in the manufacturing method of a laminated dry battery.
The purpose is to improve storage performance. In general, a unit cell 7 in a stacked dry battery is constructed between a carbon-zinc bonded electrode 3, which has a carbon film 2 formed on one side of a zinc plate 1, and an anode mixture 4, as shown in FIG. A separator 5 is interposed, an electrolytic solution is added thereto, and the heat-shrinkable resin tube 6 is covered with the heat-shrinkable resin tube 6, and the heat-shrinkable resin tube 6 is heated to shrink. 5 and the carbon-zinc bonded electrode 3, as well as between these members and the heat-shrinkable resin tube 6. The laminated dry battery is manufactured by stacking such unit cells 7, applying pressure from above and shaping them into a block, and then immersing it in a bath of molten wax or other sealant to cover the surface of the block with the sealant. However, during the pressurization, the heat-shrinkable resin tubes on the top and bottom surfaces of the cell serve as packing, so the air in the anode mixture has no place to escape, and the separator is removed as shown in Figure 2. 5 and the heat-shrinkable resin tube 6,
Since the sealing material covers the outer surface of the battery in its original state, a large amount of air is trapped inside the battery, allowing it to be finished into a laminated dry cell battery. If a battery is manufactured with such a large amount of air still contained, corrosion due to oxidation of zinc will occur immediately after manufacture due to oxygen in the air, resulting in a decrease in battery performance. This is particularly true for laminated dry batteries that use zinc chloride as the main electrolyte, which has significantly superior initial characteristics compared to laminated dry cells that use ammonium chloride as the main electrolyte, but the following formula MnO ₂ +4Zn+ZnCl ₂ +8H ₂ O→1/2Mn ₂ O ₃・H ₂ O＋ZnCl ₂・4Z
A discharge reaction that consumes water, as shown _in tend to be attracted to the anode mixture, resulting in capacity deterioration and
As the water content in the glue layer decreases, the adhesion between the zinc and the glue layer decreases, making the zinc susceptible to corrosion. Corrosion of zinc is accelerated at the three-phase interface between the zinc surface (solid phase), electrolyte (liquid phase), and air (vapor phase), and as mentioned above, in laminated dry batteries with zinc chloride as the main electrolyte, Since the electrolyte on the zinc surface decreases during storage, if a large amount of air remains in the battery, the three-phase interface increases, and the battery performance deteriorates significantly due to zinc corrosion. This is much larger than a laminated dry cell battery that uses ammonium chloride as the main electrolyte, and may become unusable. This invention was made in light of the above circumstances, and a block obtained by stacking a required number of unit cells and forming them under pressure is left under reduced pressure to collect the contents of the unit cells present in the anode mixture, etc. After removing air and the air inside the cell existing between the resin tube and the separator, a sealant layer is formed on the surface of the block, and the sealant layer is surrounded by a heat-shrinkable resin tube. This is a stacked dry battery with improved storage stability that uses zinc chloride as the main electrolyte. In this invention, the degree of pressure reduction is determined in relation to the standing time and is not particularly limited, but
Usually 200mmHg or less is adopted. The time for leaving under reduced pressure varies depending on the degree of reduced pressure, the size of the unit cell, etc., and is not particularly limited, but is usually about 1 to 60 minutes. Since it is practically impossible to completely remove the air inside the unit cell, if the air inside the unit cell can be substantially removed, the objective can be achieved. In addition, the electrolyte composition has a zinc chloride concentration of 20% by weight or more.
35% by weight, an ammonium chloride concentration of 7% by weight or less is used, preferably a zinc chloride concentration of 20% by weight or less
35% by weight, ammonium chloride concentration between 2% and 5% by weight
Weight percentages are used. Next, the present invention will be explained in more detail with reference to Examples. Example 80% manganese dioxide and acetylene black:
15 (weight ratio) was moistened with 9 parts by weight of an electrolytic solution consisting of 23% by weight of zinc chloride, 5% by weight of ammonium chloride, and 72% by weight of water, and molded to prepare an anode mixture. Next, a carbon-zinc bonded electrode coated with an adhesive around the periphery of the carbon film is inserted into the heat-shrinkable polyvinyl chloride tube, and heated so that the heat-shrinkable tube is attached to the periphery of the carbon film of the carbon-zinc bonded electrode. The periphery of the rim was glued. Next, a separator with a glue layer formed on one side and the anode mixture were inserted onto the carbon-zinc bonded electrode, and 4.2 parts by weight of the electrolytic solution having the above composition was injected and absorbed into the separator, and then heated to absorb the heat. A unit cell was fabricated by shrinking the shrinkable tube. Next, six of these cells are stacked, a metal plate is brought into contact with the upper and lower ends, and a metal plate is pressed and shaped to form a block.
The cell was placed in a depressurized chamber adjusted to and maintained at Hg, and the air inside the cell was removed. This is immersed in a sealing material bath made of wax melted at 125°C to form a sealing material layer on the surface of the block, and the surrounding area is further covered with a heat-shrinkable polyvinyl chloride tube. A 006P type laminated dry battery was manufactured by attaching the terminal plate, inserting it into the outer can, and tightening the outer can. Next, the laminated dry battery A of the present invention according to the above embodiment, the laminated dry battery B manufactured by the conventional method without removing the air inside the block as described above, and the electrolyte were made of 28% by weight of ammonium chloride and 20% by weight of zinc chloride. A laminated dry battery C manufactured by changing to an ammonium chloride type consisting of 57% by weight and 57% water and without removing the air inside the block, and a battery using ammonium chloride as the main electrolyte like laminated dry battery C as an electrolyte. After removing the air from the block used, the battery characteristics of the manufactured laminated dry cell D were measured both initially and after storage at 45° C. for 3 months, and the results are shown in Table 1.

[Table] As shown in Table 1, the laminated dry batteries A made by the method of this invention are laminated dry batteries B and C made by the conventional method.
The battery characteristics are better both initially and after storage, compared to
Moreover, there is little deterioration in battery performance due to storage. Furthermore, the battery performance of the stacked dry battery A of the present invention is superior to that of the stacked dry battery D, which uses ammonium chloride as the main electrolyte and is manufactured by removing air from the block as in the present invention. As detailed above, this invention improves storage stability by leaving the block under reduced pressure to remove the air inside the block when producing a laminated dry battery using zinc chloride as the main electrolyte. be.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view showing an example of a unit cell, and Figure 2 is a cross-sectional view showing an example of a unit cell, and Figure 2 is a cross-sectional view of an example of a unit cell. FIG. FIG. 3 is a process flow diagram showing the manufacturing process of the present invention. 5...Separator, 6...Heat-shrinkable resin tube, 7...Battery.

Claims (1)

[Scope of Claims] 1. In manufacturing a laminated dry battery using zinc chloride as the main electrolyte, (a) stacking a required number of unit cells 7 using zinc chloride as the main electrolyte and forming a block by pressure forming; (b) A step of leaving the block in (A) under reduced pressure to remove the air inside each unit cell 7; (c) Forming a sealing material layer on the surface of the block in (B); (d) Forming a sealing material layer on the block in (C) above. A method for manufacturing a laminated dry cell battery that includes the step of enclosing the periphery of the sealing material layer with a heat-shrinkable resin tube.