JPH0216549B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to the improvement of dry batteries, and an object of the present invention is to provide a dry battery with improved sealing performance and excellent storage performance. As shown in Fig. 3, the conventional top sealing structure of a dry cell is an opening of a zinc can 1 into which power generating elements such as a separator 2, a bottom paper, an anode mixture 4, an electrolyte, a top cover paper 5, and a carbon rod 6 are inserted. The zinc can 1 is sealed with a synthetic resin sealing body 7 having a through hole in the center through which a carbon rod passes, and the heat-shrinkable resin tube 8 is heat-shrinked to form a zinc can 1.
The outer peripheral part of the carbon rod 6 is covered, and the upper end thereof is extended to the upper part of the sealing body 7.The anode terminal plate 12 is fitted onto the head of the carbon rod 6, and the anode terminal plate 12 is attached to the heat-shrinkable resin tube 8. an insulating ring 13 is placed on the outer peripheral edge of the anode terminal plate 12,
The upper end of the metal outer can 14 is bent inward and the outer peripheral edge of the anode terminal plate 12 is inserted through the insulating ring 13.
It has a structure in which the upper end of a heat-shrinkable resin tube 8 extending above the sealing body 7 and the sealing body 7 are tightened downward. However, since the upper end of the heat-shrinkable resin tube 8 and the sealing body 7 are made of resin, the sealing performance is relatively good. The sealing performance is not necessarily good, and therefore, air leaks from the outside between the insulating ring 13 and the anode terminal plate 12 and between the anode terminal plate 12 and the upper end of the heat-shrinkable resin tube 8 during storage. The problem is that zinc flows into the battery through the gap between the sealing body 7 and the carbon rod 6, and corrodes the zinc can 1, causing an increase in internal resistance, a decrease in short-circuit current, and a decrease in open-circuit voltage. There is. Therefore, the upper side of the through hole of the sealing body 7 is formed into a tapered shape, and a groove 15 having a rectangular cross section is formed on the contact surface between the carbon rod 6 and the upper part of the sealing body 7. There have been proposals to fill the sealing material 16 such as crystalline wax to improve the sealing between the sealing body 7 and the carbon rod 6 and to prevent air from flowing into the battery. As a result, sufficient results have not always been achieved. In view of such circumstances, the present invention provides a swelling agent capable of swelling the upper end of the heat-shrinkable resin tube between the upper end of the heat-shrinkable resin tube extending above the sealing body and the anode terminal plate. by interposing a sealing material containing (Increasing the volume of the upper end of the heat-shrinkable resin tube by absorbing the swelling agent in the sealant into the upper end) improves the sealing performance between the anode terminal plate and the upper end of the heat-shrinkable resin tube. This makes it possible to obtain a dry battery with high storage capacity and good storage properties. FIG. 1 is a partial sectional view showing an example of a dry cell according to the present invention, and FIG. 2 is an enlarged view of the upper sealed part of the dry cell shown in FIG. 3 and 3 are inserted so that the glue layer side of the separator 2 is in contact with the inner surface of the zinc can 1, and the anode mixture 4 that has been wetted and molded with electrolyte is placed in the hollow part of the separator 2, and the remaining electrolyte is injected. The upper end of the separator 2 is folded inward along the upper surface of the anode mixture 4, and a top cover paper 5 having a through hole in the center is placed on top of it. Press the zinc can 1, the separator 2, the anode mixture 4, the top cover paper 5, etc. into tight contact, press the carbon rod 6 into the center of the anode mixture 4 through the hole in the top cover paper 5, and then close the zinc can. The upper end of the opening of 1 is bent inward, and a polyethylene sealing body 7 having a through hole in the center through which the carbon rod passes is fitted onto the carbon rod 6, and the lower surface of the outer periphery is bent at the bent part of the opening of the zinc can. After sealing the opening of the zinc can 1 by contacting the zinc can 1 with
is attached, and the heat-shrinkable resin tube 8 is heated and heat-shrinked to cover the outer periphery of the zinc can 1, and the upper end of the heat-shrinkable resin tube 8 is extended to the top of the sealing body 7. , and the lower end of the heat-shrinkable resin tube 8 extends to the lower part of the resin ring 10, and then the upper end of the heat-shrinkable resin tube 8 extends to the upper part of the sealing body 7 as shown in FIG. A sealing material 11 containing a swelling agent that swells the upper end of the heat-shrinkable resin tube 8 is applied to the upper part of the heat-shrinkable resin tube 8 and the upper part of the sealing body 7, and then the anode terminal plate 12 is fitted onto the head of the carbon rod 6. Then, the anode terminal plate 12 is brought into contact with the upper end of the heat-shrinkable resin tube 8 via the sealing material 11, the insulating ring 13 is placed on the outer peripheral edge of the anode terminal plate 12, and the metal exterior can The upper end of the heat-shrinkable resin tube 8 is bent inward to extend through the insulating ring 13 to the outer peripheral edge of the anode terminal plate 12 and the upper part of the sealing body 7 .
It is made by tightening the material downward and sealing it. As the heat-shrinkable resin tube, one made of vinyl chloride resin is usually used, and in other cases, one made of polypropylene is used. When the heat-shrinkable resin tube is made of vinyl chloride resin, chloroform, methyl acetate, ethyl acetate, benzene, etc. are used as the swelling agent to swell the upper end of the heat-shrinkable resin tube. When the polypropylene resin tube is made of polypropylene, aromatic hydrocarbons such as benzene, xylene, and toluene are used under slight heating conditions. In addition, when using these swelling agents, it is necessary to select one that does not destroy the sealing body. Examples of base materials for the sealant include paraffin wax, microcrystalline wax, a mixture of paraffin wax and microcrystalline wax with polybutene, petrolatum or petrolatum, and aliphatic hydrocarbons with a higher melting point than these. A mixture of petrolatum and petrolatum, petrolatum or petrolatum with polyethylene added, etc. are used. The ratio of these bases and swelling agents is usually selected to be in the range of 3:7 to 7:3 by weight. In addition to the function of swelling the upper end of the heat-shrinkable resin tube extending above the sealing body, the sealing material containing such a swelling agent has the function of swelling the upper end of the anode terminal plate and the heat-shrinkable resin tube and the sealing body. The original function of the sealant is to fill the gap between the anode terminal plate and the upper end of the heat-shrinkable resin tube and the sealant to prevent air from entering the battery. Therefore, the heat-shrinkable resin tube may be interposed between the upper part of the sealing body and the anode terminal plate where it is not arranged. As shown in the figure, in order to swell the upper end of the heat-shrinkable resin tube extending above the sealing body and improve the sealing between the upper end of the heat-shrinkable resin tube and the anode terminal plate, It is best to interpose a sealing material containing a swelling agent between the upper end of the heat-shrinkable resin tube extending above the sealing body and the anode terminal plate from the beginning. Since the sealing material has fluidity, instead of it, a sealing material containing a swelling agent is interposed between the anode terminal plate and the upper part of the sealing body, where the heat-shrinkable resin tube is not placed at the beginning. Over time, the sealing material containing the swelling agent flows between the upper end of the heat-shrinkable resin tube extending above the sealing body and the anode terminal plate, and the sealing material containing the swelling agent flows into the upper part of the sealing body. The heat-shrinkable resin tube may be interposed between the upper end of the heat-shrinkable resin tube and the anode terminal plate. However, in this case, it may take some time for the upper end of the heat-shrinkable resin tube to swell, or the degree of swelling may be small, so that the effect is only slightly reduced. Table 1 below shows the open circuit voltage and short circuit current of dry cell A of the present invention and conventional dry cell B after initial storage and after storage at 20° C. for 6 months.

[Table] All batteries used zinc chloride type electrolyte.
This is a SUM-1 type dry battery, and the sealing body is made of polyethylene, and the heat-shrinkable resin tube is made of vinyl chloride resin. For dry battery A, a mixture of microcrystalline wax and benzene at a weight ratio of 5:5 was used as a sealant, and this sealant containing a swelling agent was heated and extended to the top of the sealant. It was applied to the upper part of the upper end of the heat-shrinkable vinyl chloride resin tube, and also applied to the upper part of the sealing body where the heat-shrinkable vinyl chloride resin tube was not placed, and assembled as shown in Figures 1 and 2. Dry battery B is assembled by pouring microcrystalline wax into a groove having a rectangular cross section formed between the sealing body and the anode terminal plate and between the carbon rod and the upper part of the sealing body. As shown in Table 1, there was no particularly large difference observed between the dry batteries A and B at the beginning, but after storage, the dry batteries A and B of this invention
Compared to conventional dry battery B, both open circuit voltage and short circuit current were larger, and storage performance was excellent. In addition, in the embodiments etc., a case has been described in which a sealing material layer for sealing the opening of the zinc can 1 is not provided on the top cover paper 5, but the present invention is not limited to this. The present invention is applicable not only to those provided with a sealing material layer but also to those with some changes and modifications within the scope of the spirit of the present invention. As detailed above, the present invention contains a swelling agent capable of swelling the upper end of the heat-shrinkable resin tube between the upper end of the heat-shrinkable resin tube extending above the sealing body and the anode terminal plate. The upper end of the heat-shrinkable resin tube extending to the upper part of the sealing body is swollen with a sealant interposed therebetween to improve the sealing performance between the anode terminal plate and the upper end of the heat-shrinkable resin tube. The present invention provides a dry battery with good performance.

[Brief explanation of drawings]

FIG. 1 is a partial sectional view showing an example of a dry battery of the present invention, FIG. 2 is an enlarged view of the main part of FIG. 1, and FIG. 3 is a sectional view showing a part of a conventional dry battery. 1... Zinc can, 6... Carbon rod, 7... Sealing body,
8... Heat-shrinkable resin tube, 11... Sealing material containing swelling agent, 12... Anode terminal plate, 13...
Insulation ring, 14...metal exterior can.

Claims (1)

[Claims] 1. The opening of the zinc can containing the power generation element is sealed with a synthetic resin sealing body, the heat-shrinkable resin tube is heat-shrinked to cover the outer periphery of the zinc can, and the upper end is covered with the sealing body. The carbon rod is extended to the top, the anode terminal plate is fitted onto the head of the carbon rod, the anode terminal plate is brought into contact with the upper end of the heat-shrinkable resin tube, and the insulating ring is placed on the outer periphery of the anode terminal plate. Then, the upper end of the metal exterior can is bent inward, and the outer peripheral edge of the anode terminal plate, the upper end of the heat-shrinkable resin tube extending to the top of the sealing body, and the sealing body are inserted downward through the insulating ring. In dry batteries manufactured through a process of tightening, a swelling agent is provided between the upper end of the heat-shrinkable resin tube extending above the sealing body and the anode terminal plate to swell the upper end of the heat-shrinkable resin tube. A dry battery characterized by interposing a sealing material containing.