JP2005116361A - Negative electrode can and manganese dry cell using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a negative electrode can which has can-forming processability, mechanical strength, and corrosion resistance without containing lead, but equal to or larger than processability when it contains lead. <P>SOLUTION: The negative electrode can for a manganese dry cell is made of a zinc alloy which does not contain lead and contains indium 0.01-0.5 wt%, and contains at least one kind selected from a group of niobium and beryllium 0.001-0.5 wt%. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a manganese battery, particularly a negative electrode can made of a zinc alloy not containing lead.

Conventionally, in a negative electrode can in a manganese dry battery, lead has been added to zinc in order to increase the workability and mechanical strength of zinc used as a material and to further improve the corrosion resistance.
However, in recent years, in order to prevent environmental pollution caused by dry batteries after use, various studies have been made in the direction of not using harmful substances such as mercury, cadmium, and lead for members constituting the batteries.

For example, in Patent Document 1, as a material constituting the negative electrode can, a zinc alloy containing 0.05 to 0.5% by weight of indium and 0.001 to 0.05% by weight of at least one of aluminum and gallium It has been proposed to use
However, when indium is added to zinc, the corrosion resistance of zinc is improved, but there is a problem that the mechanical strength after the can is lowered. Further, when aluminum or gallium is added to zinc, the mechanical strength after the can is improved, but there is a problem that the corrosion resistance and workability of zinc are not good.
JP-A-6-196156

  In order to solve the above problems, the present invention provides a negative electrode can which does not contain lead and has a can processability, mechanical strength, and corrosion resistance equivalent to or higher than that of conventional lead. The purpose is to do. Moreover, it aims at providing an environmentally friendly manganese dry battery by using this negative electrode can.

The negative electrode can for manganese dry batteries of the present invention does not contain lead, contains 0.01 to 0.5% by weight of indium, and contains at least one selected from the group consisting of niobium and beryllium in an amount of 0.001 to 0.00. It consists of a zinc alloy containing 5% by weight.
The present invention also relates to a manganese dry battery using the above negative electrode can.

  ADVANTAGE OF THE INVENTION According to this invention, the negative electrode can which does not contain lead but has the workability, mechanical strength, and corrosion resistance equivalent or more than the case where the conventional lead is contained can be provided. Moreover, an environmentally friendly manganese dry battery can be provided by using this negative electrode can.

The present invention does not contain lead, contains 0.01 to 0.5% by weight of indium, and contains 0.001 to 0.5% by weight of at least one selected from the group consisting of niobium and beryllium. The present invention relates to a negative electrode can for manganese dry batteries made of an alloy.
At this time, the negative electrode can which does not contain lead and has can processability, mechanical strength, and corrosion resistance with respect to the electrolytic solution equivalent to or higher than the case of containing lead can be obtained.

Since indium, niobium and beryllium have a large hydrogen overvoltage, the hydrogen overvoltage on the zinc surface is increased, the generation of hydrogen gas in the negative electrode can is suppressed, and the corrosion resistance to the electrolyte is improved.
Moreover, since said niobium and beryllium have the effect which improves the ductility and hardness of pure zinc, the can processability of a negative electrode can and the mechanical strength after a can improve.

However, when the content of indium is less than 0.01% by weight, the effect of containing indium becomes insufficient. On the other hand, when the content exceeds 0.5% by weight, the mechanical strength decreases. In particular, the indium content is more preferably 0.05 to 0.15% by weight.
On the other hand, when the total content of one or both of niobium and beryllium is less than 0.001% by weight, the effect of niobium and beryllium becomes insufficient. On the other hand, when the content exceeds 0.5% by weight, durability against the electrolytic solution is lowered.

Moreover, in the manganese dry battery using this negative electrode can, since harmful lead is not contained in the negative electrode can, environmental pollution can be suppressed.
Hereinafter, embodiments of the present invention will be described in detail.

<< Examples 1-12 and Comparative Examples 1-14 >>
(I) Production of negative electrode can Using a low-frequency induction furnace, 99.99% by weight of zinc was melted at about 500 ° C., and a predetermined amount of elements shown in Table 1 were added thereto, respectively, Obtained. And while cooling these zinc alloy molten metal, it rolled into the plate shape of predetermined thickness, and obtained the alloy plate, respectively. These alloy plates were punched with a press to obtain round or hexagonal pieces having a predetermined size. Using these small pieces, R20 and R6 size negative electrode cans for bottomed cylindrical single-unit and single-unit manganese batteries were obtained by impact molding.

(Ii) Preparation of positive electrode mixture Manganese dioxide, conductive carbon black, and an electrolytic solution containing 30 parts by weight of zinc chloride and 70 parts by weight of water are mixed at a weight ratio of 50:10:40 and molded to form a positive electrode. A mixture was obtained.

(Iii) Assembly of Manganese Battery Using the R6 size negative electrode can obtained above, an AA manganese battery having the configuration shown in FIG.
The cylindrical positive electrode mixture 1 was accommodated in the negative electrode can 4 obtained above through the separator 3. A carbon rod 2 in which carbon powder was hardened was inserted into the central portion of the positive electrode mixture.

The sealing body 5 was made of a polyolefin-based resin and provided with a hole for inserting the carbon rod 2 in the center. The paper 9 was obtained by punching a paperboard into an annular shape having a center hole, and was placed on the top of the positive electrode mixture 1. The upper part of the carbon rod 2 penetrating the sealing body 5 and the central hole of the paper 9 was brought into contact with the positive electrode terminal 11 so as to act as a positive electrode current collector.
A resin tube 8 made of a heat-shrinkable resin film is provided on the outer periphery of the negative electrode can 4 to cover the upper surface of the outer periphery of the sealing body 5 at its upper end and to be sealed at its lower end. The lower surface of the ring 7 was covered.

  The positive electrode terminal 11 made of a tin plate was provided with a shape having a cap-shaped central portion and a flat plate-shaped flange portion that covers the upper end portion of the carbon rod 2. An insulating ring 12 made of resin was disposed on the flat collar portion of the positive electrode terminal 11. A bottom paper 13 was provided between the bottom of the positive electrode mixture 1 and the negative electrode can 4 in order to ensure insulation. A seal ring 7 is disposed on the outer surface side of the flat plate-like outer peripheral portion of the negative electrode terminal 6.

A metal outer can 10 made of a cylindrical tin plate is placed outside the resin tube 8, its lower end is bent inward, its upper end is curled inward, and the tip of its upper end is insulated with an insulating ring 12 was contacted. In this way, the insulating ring 12, the flat collar of the positive terminal 11, the upper end of the resin tube 8, the outer periphery of the sealing body 5, the open end of the negative electrode can 4, and the lower end of the resin tube 8, The seal ring 7 and the negative electrode terminal 6 were each fixed at a predetermined position.
Each negative electrode can and manganese dry battery obtained above were evaluated as follows.

[Evaluation]
(1) Mechanical strength of negative electrode can As shown in FIG. 2, a bottomed cylindrical R20 size negative electrode can 14 was placed on a V block 15. And the conical pressure terminal 16 was pressed on the outer surface of 10 mm from the opening part of the negative electrode can 14. The amount of change when the point pressed by the pressure terminal 16 moved and the force applied to this point were recorded with a recorder. Since the R20 size negative electrode can 14 shows a substantially constant value at about 4 mm, the force applied to the measurement point at the time of 4 mm transition is defined as the mechanical strength of the negative electrode can 14 for convenience.

(2) Corrosion resistance of the negative electrode can In order to evaluate the corrosion resistance of the negative electrode can to the electrolyte, the amount of hydrogen gas generated when an R20 size negative electrode can cut into a constant weight was immersed in an electrolyte at 45 ° C. I investigated. Note that an aqueous solution containing 30% by weight of zinc chloride was used as the electrolytic solution.

(3) Discharge performance of manganese dry batteries Cycles in which batteries were initially stored at 45 ° C for 3 months, discharged at 1.8Ω load for 15 seconds in an environment of 20 ± 2 ° C, and then stopped for 45 seconds. Was repeated until the closed circuit voltage reached 0.9V. And discharge performance was evaluated by the number of cycles at this time.

Table 2 shows the evaluation results of Comparative Examples 3 to 8 in which a zinc alloy containing indium was used for the negative electrode can as shown in Table 1 when indium was added . In addition, the result of the comparative example 1 in case zinc contains 0.4 weight% of lead as a conventional product, and the comparative example 2 in the case of only zinc is also shown.

When indium was contained in an amount of 0.01% by weight or more, the mechanical strength of the negative electrode can was improved to some extent. In addition, the amount of hydrogen gas generated was greatly reduced, and the corrosion resistance to the electrolyte was improved. However, when the content exceeded 0.5% by weight, the mechanical strength decreased. From this, it was found that the content of indium is preferably 0.01 to 0.5% by weight.
However, sufficient mechanical strength and corrosion resistance could not be obtained only by containing indium as compared with the conventional negative electrode can of Comparative Example 1. In addition, in a battery using a zinc alloy containing indium in such a range for a negative electrode can, the discharge characteristics after storage at 45 ° C. for 3 months were large, and sufficient storage characteristics could not be obtained.

  From the above, it was found that the content of indium is preferably 0.01 to 0.5% by weight. However, when the content of indium is fixed at 0.1% by weight and niobium or beryllium is further added. Was examined.

When niobium is further added to indium Table 3 shows the evaluation results of Examples 1 to 4 and Comparative Examples 9 and 10 in which a zinc alloy containing indium and niobium was used for the negative electrode can as shown in Table 1.

The higher the niobium content, the better the mechanical strength of the negative electrode can. The amount of hydrogen gas generated in the negative electrode can was almost the same as that in Comparative Example 1. However, in Comparative Example 10 where the niobium content was 1.0% by weight, the amount of hydrogen gas generated increased. Further, as the battery characteristics, when the niobium content was 0.5% by weight or less, the storage characteristics improved as the content increased. However, in Comparative Example 10 having a content of 1.0% by weight, the storage characteristics deteriorated. In Comparative Example 9 in which the niobium content was 0.0005% by weight, the negative electrode can had low mechanical strength, a large amount of hydrogen gas was generated, and the storage characteristics of the battery deteriorated.
From Table 3, it was found that in Examples 1 to 4 containing 0.001 to 0.5% by weight of niobium, mechanical strength and corrosion resistance superior to those of the conventional product of Comparative Example 1 were obtained.

Table 4 shows the evaluation results of Examples 5 to 8 and Comparative Examples 11 and 12 in which a zinc alloy containing indium and beryllium was used for the negative electrode can as shown in Table 1 when beryllium was further added to indium.

The higher the beryllium content, the better the mechanical strength of the negative electrode can. The amount of hydrogen gas generated in the negative electrode can was almost the same as that in Comparative Example 1. However, in Comparative Example 12 in which the beryllium content was 1.0% by weight, the hydrogen gas generation amount increased. Further, as the battery characteristics, when the content of beryllium is 0.5% by weight or less, the storage characteristics improved as the content increased, but in Comparative Example 12 having a content of 1.0% by weight, the storage characteristics were improved. Became worse. In Comparative Example 11 in which the beryllium content was 0.0005% by weight, the negative electrode can had low mechanical strength, a large amount of hydrogen gas was generated, and the storage characteristics of the battery deteriorated.
From Table 4, it was found that in Examples 5 to 8 containing 0.001 to 0.5% by weight of beryllium, mechanical strength and corrosion resistance superior to the conventional product of Comparative Example 1 were obtained.

When niobium and beryllium were further added to indium, as shown in Table 1, a zinc alloy containing 0.1% by weight of indium and further containing niobium and beryllium at a weight ratio of 1: 1 was used for the negative electrode can. Table 5 shows the evaluation results of Examples 9 to 12 and Comparative Examples 13 and 14.

  The higher the content of niobium and beryllium, the better the mechanical strength of the negative electrode can. The amount of hydrogen gas generated in the negative electrode can was almost the same as that in Comparative Example 1. However, in Comparative Example 14 where the total content of niobium and beryllium was 1.0% by weight, the amount of hydrogen gas generated increased. In addition, as for battery characteristics, when the total content of niobium and beryllium is 0.5% by weight or less, the storage characteristics improved as the content increased, but the total content of niobium and beryllium was 1. In Comparative Example 14 of 0% by weight, the storage characteristics deteriorated. In Comparative Example 13 in which the total content of niobium and beryllium was 0.0005% by weight, the mechanical strength of the negative electrode can was low, the amount of hydrogen gas generated was large, and the storage characteristics of the battery deteriorated.

From Table 5, it was found that in Examples 9 to 12 containing 0.001 to 0.5% by weight of niobium and beryllium in total, mechanical strength and corrosion resistance superior to the conventional product of Comparative Example 1 were obtained. .
In the above, the addition effect of niobium and beryllium is shown in the case of containing 0.1% by weight of indium, but the same effect is obtained when the indium content is in the range of 0.01 to 0.5% by weight. can get.

  As described above, the negative electrode can for manganese dry battery of the present invention does not contain lead, and has mechanical strength, can processability, and corrosion resistance equal to or higher than that of a conventional negative electrode can containing lead. It can be applied to manganese dry batteries that do not use harmful substances such as lead.

It is the front view which made a part of manganese dry battery of the present invention a section. It is a figure which shows the measuring method of the mechanical strength of a negative electrode can.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Positive electrode mixture 2 Carbon rod 3 Separator 4, 14 Negative electrode can 5 Sealing body 6 Negative electrode terminal 7 Seal ring 8 Resin tube 9 Paperboard 10 Metal armored can 11 Positive electrode terminal 12 Insulation ring 13 Bottom paper 15 V block 16 Pressure terminal

Claims (2)

  Manganese made of zinc alloy not containing lead, containing 0.01 to 0.5% by weight of indium, and containing 0.001 to 0.5% by weight of at least one selected from the group consisting of niobium and beryllium Negative electrode can for dry batteries.   A manganese dry battery using the negative electrode can for manganese dry battery according to claim 1.

Images