JP2006012685A - Paste type manganese dry battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paste type manganese dry battery having high discharge characteristics and high storage characteristics by continuing corrosion resistance of a negative electrode can from the initial stage for a long time. <P>SOLUTION: An electrolyte in a paste layer in the paste type manganese dry battery contains 10 wt% or more ammonium chloride, and the paste layer contains bismuth equivalent to 0.0005-0.5 wt% of the electrolyte contained in the paste layer. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an anhydrous silver paste-type manganese dry battery, and more particularly to improvement of discharge characteristics and storage characteristics.

  Conventionally, in paste-type manganese batteries, 0.01 to 0.1% by weight of a mercury compound such as mercuric chloride is added to the paste layer in order to suppress self-discharge. By adding such a mercury compound, the zinc surface is amalgamated and the hydrogen overvoltage is maintained at a high level, so that corrosion of zinc can be prevented.

  However, awareness of environmental pollution on the earth is increasing day by day, and silver-free manganese paste batteries are also desired. As a means for improving the corrosion resistance of the negative electrode zinc can without using mercury, it has been proposed to add indium chloride into the glue layer (for example, Patent Document 1).

By the way, in order to improve the corrosion resistance of the negative electrode can, a zinc alloy containing 0.4% by weight of lead is usually used for the negative electrode can. Furthermore, if the amount of lead in the negative electrode can is reduced to less than 0.4% by weight as an environmental measure, a large amount of indium chloride is required to maintain the corrosion resistance of the negative electrode can. As a result, the negative electrode can surface is covered with an indium coating, whereby the internal resistance increases and the discharge characteristics deteriorate. Further, since a large amount of indium chloride is required, the cost increases.
JP-A-6-163019

  Therefore, in order to solve the above-mentioned conventional problems, the present invention maintains the corrosion resistance of the negative electrode can for a long period from the beginning without using mercury and lead, and has a paste type manganese having excellent discharge characteristics and storage characteristics. An object is to provide a dry battery.

  The paste-type manganese dry battery of the present invention comprises a positive electrode mixture containing manganese dioxide; a negative electrode can containing zinc; and a paste layer containing starch, a water-soluble paste, and an electrolyte that separates the positive electrode mixture and the negative electrode can. A paste-type manganese dry battery, wherein the electrolyte solution in the paste layer contains 10% by weight or more of ammonium chloride, and the paste layer is 0.0005 to 0.5% by weight of the electrolyte solution contained in the paste layer. % Bismuth.

The bismuth is preferably included as a bismuth compound.
The bismuth compound is preferably at least one selected from the group consisting of bismuth chloride and bismuth oxide.
It is preferable that the paste layer further contains indium chloride containing indium corresponding to 0.001 to 0.5% by weight of the electrolyte contained in the paste layer.
The negative electrode can is preferably made of zinc or a zinc alloy containing no lead.

  ADVANTAGE OF THE INVENTION According to this invention, the paste-type manganese dry battery which has the outstanding discharge characteristic and storage characteristic can be provided by maintaining the corrosion resistance of a negative electrode can over the long term from the beginning, without using mercury and lead.

  The present invention is characterized in that the adhesive layer, which is a separator that separates the positive electrode and the negative electrode in the paste-type manganese dry battery, contains bismuth. This glue layer consists of starch, a water-soluble glue, and an electrolyte solution. The electrolyte is an aqueous solution of zinc chloride and ammonium chloride. Bismuth is added to the glue layer as a bismuth compound. As the water-soluble paste, for example, polyethylene glycol alkylphenol is used.

  In this adhesive layer, the bismuth compound reacts with ammonium ions in the electrolytic solution and is considered to exist as an ammonium salt of bismuth. This ammonium salt quickly precipitates as metal bismuth by an electron exchange reaction with metal zinc on the zinc surface, and the hydrogen overvoltage on the zinc surface can be increased. Thus, the bismuth compound exhibits the effect of suppressing the corrosion of the zinc negative electrode can and suppressing self-discharge, like mercury.

The electrolyte solution in the glue layer contains 10% by weight or more of ammonium chloride, and the glue layer contains bismuth corresponding to 0.0005 to 0.5% by weight of the electrolyte solution contained in the glue layer. At this time, excellent discharge performance is obtained, and in particular, excellent discharge performance is obtained even after long-term storage, and storage characteristics are improved.
When the bismuth content exceeds 0.5% by weight, the internal resistance increases and the discharge performance decreases. On the other hand, if the bismuth content is less than 0.0005% by weight, the effect of the corrosion resistance of the negative electrode can becomes insufficient.

The bismuth compound is preferably at least one selected from the group consisting of bismuth chloride and bismuth oxide. The bismuth chloride include BiCl _3. Bi ₂ O ₃ is an example of the bismuth oxide.
In addition, when the concentration of ammonium chloride in the electrolytic solution is less than 10% by weight, bismuth is difficult to dissolve in the electrolytic solution, so the amount of bismuth deposited on the negative electrode can decreases, and the effect of improving the corrosion resistance of the negative electrode can by adding bismuth is effective. Get smaller.

It is preferable that the paste layer further contains indium chloride containing indium corresponding to 0.001 to 0.5% by weight of the electrolyte contained in the paste layer.
When only the bismuth compound is added to the glue layer, the voltage variation of the product is slightly larger than when mercury is added. However, when indium chloride is further added to the bismuth compound, the surface of the negative electrode can is made of indium or bismuth. Therefore, the voltage variation can be suppressed to the same level as when mercury is added.

The mechanism of suppressing voltage variation by adding indium is estimated as follows.
When an ammonium salt of bismuth is present in the electrolytic solution, metal bismuth is unevenly distributed on the surface of the zinc negative electrode can. Metal bismuth has a low ductility and low electronic conductivity. However, when bismuth and indium coexist, metal indium with high ductility and high electron conductivity is deposited together with bismuth, so the surface of the zinc negative electrode can be uniformly covered with both metals and stable corrosion resistance is obtained. It is done.

Examples of indium chloride include InCl, InCl ₃ , In ₂ Cl ₃ , In ₄ Cl ₇ , and In ₅ Cl ₉ . Similar effects can be obtained with other halides, and examples thereof include InBr ₃ , InF ₃ , and InI ₃ .
For the negative electrode can, a zinc alloy containing 4% by weight of lead is conventionally used for the purpose of improving the corrosion resistance of the negative electrode can, but even when lead is reduced or no lead is added in consideration of the environment. By using the paste layer, a negative electrode can excellent in corrosion resistance is obtained, and a paste-type manganese dry battery excellent in discharge characteristics and storage characteristics is obtained. That is, in the present invention, a paste-type manganese dry battery that does not use lead and mercury can be obtained, and a battery that is excellent in terms of environment can be configured.

Hereinafter, embodiments of the present invention will be described in detail.
<< Examples 1-4 and Comparative Examples 1-3 >>
Whether bismuth was dissolved in the electrolytic solution was examined by the following method.
Zinc chloride, ammonium chloride and water were mixed in the proportions shown in Table 1 to obtain an electrolytic solution. Bismuth was added to the electrolyte as BiCl ₃ or Bi ₂ O ₃ in an amount of 0.1% by weight with respect to the weight of the zinc plate, and then stirred. And the zinc plate was thrown into this electrolyte solution. After being left for 1 hour, the amount of bismuth deposited on the surface of the zinc plate was measured. The results are shown in Table 1.

It was found that in the electrolytic solution containing 10% by weight or more of ammonium chloride, 0.06% by weight or more was deposited when the bismuth was BiCl ₃ and 0.04% by weight or more when Bi ₂ O ₃ was used. On the other hand, when the concentration of ammonium chloride is less than 10% by weight, the amount of bismuth deposited is 0.01% by weight or less. Therefore, when the concentration of ammonium chloride is less than 10% by weight, bismuth is difficult to dissolve in the electrolytic solution. It was found that is difficult to deposit on the zinc plate.

  In Examples 1 to 3, bismuth was deposited almost completely on the zinc plate after being left for 24 hours and in Example 4 after being left for 96 hours. As a result, when an electrolytic solution having an ammonium chloride concentration of 10% by weight or more is used, bismuth is sufficiently dissolved in the electrolytic solution, and bismuth can be completely deposited on the zinc plate, effectively and effectively. Found the fact that bismuth can be used.

<< Examples 5 to 23 and Comparative Examples 4 to 7 >>
(1) Preparation of paste layer paste Zinc chloride, ammonium chloride, and water were mixed at a weight ratio of 10:20:70 to obtain an electrolytic solution. And this electrolyte solution, starch powder, and a water-soluble paste are mixed in the ratio of weight ratio 75: 24: 1, The compound of the ratio shown in Table 2 with respect to the amount of electrolyte solution is added to this mixture, A paste for paste layer was obtained. In Table 2, the addition amounts of InCl ₃ , BiCl ₃ , and Bi ₂ O ₃ are values converted into indium or bismuth amounts, respectively.

(2) Assembly of paste-type manganese dry battery A paste-type manganese dry battery was produced according to the following procedure. FIG. 1 is a front view showing a cross section of a part of the paste-type manganese battery of the present invention.
A zinc alloy containing 0.4% by weight of lead was molded into a bottomed cylindrical shape, and a negative electrode can 3 was obtained. After placing the bottom paper 5 on the inner bottom surface of the negative electrode can 3, the paste for paste layer was filled. Next, the positive electrode mixture 2 into which the carbon rod 1 obtained by sintering carbon powder in advance was inserted, and the paste layer 4 was arranged between the positive electrode mixture 2 and the negative electrode can 3. . Here, the positive electrode mixture 2 is a mixture of manganese dioxide as an active material, acetylene black as a conductive material, and an electrolytic solution composed of a 30 wt% aqueous solution of zinc chloride in a weight ratio of 50:10:40. Using.

A hole for inserting the carbon rod 1 was provided at the center of the sealing body 9 made of polyolefin resin. The carbon rod 1 was press-fitted into the hole of the sealing body 9, and the peripheral portion of the sealing body 9 was fitted to the opening end of the negative electrode can 3. And the positive electrode terminal 6 was made to fit on the upper part of the carbon rod 1 which is a collector of a positive electrode.
A resin tube 11 made of a heat-shrinkable resin film is provided on the outer periphery of the negative electrode can 3 to cover the upper surface of the outer peripheral portion of the sealing body 9 at its upper end and to be sealed at its lower end. The lower surface of the ring 13 was covered. A sealing plate 7 was disposed on the upper part of the sealing body 9.

The positive electrode terminal 6 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 1. A resin-made insulating ring 8 was disposed on the flat collar portion of the positive electrode terminal 6 and separated from the sealing plate 7. A bottom plate 10 also serving as a negative electrode terminal was disposed on the bottom surface of the negative electrode can 3, and a seal ring 13 was disposed on the outer surface side of the flat plate-like outer peripheral portion of the bottom plate 10.
An outer can 12 made of a cylindrical tin plate is placed outside the resin tube 11, its lower end is bent inward, its upper end is curled inward, and the tip of its upper end is a sealing plate 7 was crimped to the outer peripheral edge.

[Evaluation]
(A) Evaluation of initial characteristics The battery immediately after production was discharged with a load of 2.2Ω, and the discharge time was measured. At this time, the end voltage was 0.8V. The number of battery tests was five, and the average value at this time was defined as the discharge time in each battery. When the discharge time was 125 minutes or more, it was evaluated that the discharge characteristics were good.

(B) Evaluation of storage characteristics After measuring the battery voltage of the battery immediately after production, it was stored at room temperature for 12 months. The battery voltage was measured again for the battery after storage, and the decrease in battery voltage after storage relative to the initial stage was examined. The number of tests of the battery was 100, and the average value at this time was defined as the decrease in battery voltage in each battery. When the battery voltage drop was 45 mV or less, it was evaluated that the storage characteristics were good.
Moreover, the variation in battery voltage was determined for the battery after storage. The number of battery tests was 100, and the difference between the maximum value and the minimum value of the battery voltage was determined as variation.
These results are shown in Table 3.

(A) When a bismuth compound is added to the adhesive layer In Comparative Example 5, since the corrosion resistance of the negative electrode can was improved compared to Comparative Example 4, a decrease in battery voltage during storage was suppressed, and variations in battery voltage after storage were also observed. It has become smaller.
In Examples 5 to 13 in which a bismuth compound was added to the adhesive layer, the corrosion resistance of the negative electrode can was improved as compared with Comparative Example 5, and the decrease in battery voltage during storage was suppressed. In Examples 5 to 13, initial characteristics superior to those of Comparative Example 5 were obtained. In Comparative Example 7, since the bismuth content was large, the internal resistance increased and the discharge characteristics deteriorated. In Comparative Example 6, since the bismuth content was small, the corrosion resistance of the negative electrode can was insufficient, and the battery voltage decrease after storage increased.

(B) In the case where indium chloride is further added to the paste layer containing the bismuth compound In Examples 14 to 23, in which the indium chloride is further added to the bismuth compound in the paste layer, the corrosion resistance of the negative electrode can is improved, and during storage The decrease in battery voltage was suppressed. In Example 14, since the amount of indium chloride added was small, the effect of suppressing variation in battery voltage after storage was small. In Example 21, although the variation in battery voltage after storage was suppressed, the amount of indium chloride added was increased and the internal resistance increased, so the discharge characteristics deteriorated. In Examples 15 to 20, 22, and 23, initial discharge characteristics and storage characteristics were good, and variations in battery voltage after storage were also suppressed.

<< Examples 24-39 and Comparative Examples 8-9 >>
A paste-type manganese dry battery was prepared in the same manner as in Example 5 except that the lead content in the negative electrode can and the addition amount of bismuth chloride and indium chloride in the glue layer were changed as shown in Table 4. Initial properties and storage properties were evaluated. In Table 4, the added amounts of InCl ₃ and BiCl ₃ are values converted into indium or bismuth amounts, respectively. The results are shown in Table 5.

(C) When the amount of lead in the negative electrode can is reduced and a bismuth compound is added to the adhesive layer In Comparative Example 8, since the bismuth content is small, the corrosion resistance effect of the negative electrode can becomes insufficient, and the battery voltage after storage Decreased significantly. In Comparative Example 9, since the bismuth content was increased and the internal resistance was increased, the initial discharge characteristics were deteriorated.
On the other hand, in Examples 22 to 24 in which the amount of lead in the negative electrode can was reduced and Examples 27 to 32 not containing lead, good initial discharge characteristics and storage characteristics were obtained by adding a small amount of bismuth.

(D) When the amount of lead in the negative electrode can is reduced and indium chloride is further added to the paste layer containing the bismuth compound In Examples 34 to 38 that do not contain lead, the addition of a small amount of bismuth provides a good initial Discharge characteristics and storage characteristics were obtained, and at the same time, variation in battery voltage after storage was suppressed by the addition of indium chloride.

  In Example 33, since the amount of indium chloride added was small, the effect of suppressing variations in battery voltage after storage was small. In Example 39, the variation in battery voltage after storage was suppressed, but the amount of indium chloride added increased and the internal resistance increased, so the discharge characteristics deteriorated.

  As described above, the paste-type manganese dry battery of the present invention has excellent discharge characteristics and storage characteristics, and therefore can be applied to power supplies for high-performance small electronic devices and portable devices.

It is the front view which made a part of paste type manganese dry battery in the example of the present invention a section.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Carbon rod 2 Positive electrode mixture 3 Negative electrode can 4 Glue layer 5 Bottom paper 6 Positive electrode terminal 7 Sealing plate 8 Insulating ring 9 Sealing body 10 Bottom plate 11 Resin tube 12 Exterior can 13 Seal ring

Claims (5)

A paste-type manganese dry battery comprising a positive electrode mixture containing manganese dioxide; a negative electrode can containing zinc; and a paste layer containing starch, a water-soluble paste, and an electrolyte that separates the positive electrode mixture and the negative electrode can. ,
The electrolyte solution in the glue layer contains 10% by weight or more of ammonium chloride,
The paste-type manganese dry battery characterized in that the paste layer contains bismuth corresponding to 0.0005 to 0.5% by weight of the electrolyte contained in the paste layer.   The paste-type manganese dry battery according to claim 1, comprising the bismuth as a bismuth compound.   The paste-type manganese dry battery according to claim 2, wherein the bismuth compound is at least one selected from the group consisting of bismuth chloride and bismuth oxide.   The paste-type manganese dry battery according to claim 1, wherein the glue layer further contains indium chloride containing indium corresponding to 0.001 to 0.5% by weight of the electrolyte contained in the glue layer.   The paste-type manganese dry battery according to claim 1, wherein the negative electrode can is made of zinc or zinc alloy containing no lead.

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