JP2013125629A - Manganese dry battery - Google Patents

Abstract

A large amount of electrolyte that has moved from a positive electrode mixture during a discharge reaction is accumulated in the air chamber of the upper part of the battery, and when the amount of mobile electrolyte is larger than the volume of the air chamber, it is prevented from leaking outside the battery. And providing a manganese dry battery with improved leakage prevention.
A bottomed cylindrical negative electrode zinc can, a positive electrode mixture 1 containing manganese dioxide, carbon powder and an electrolyte contained in the negative electrode zinc can 4, the negative electrode zinc can 4 and the positive electrode mixture 1, In a manganese dry battery provided with a separator 3 disposed between and coated with a paste material, the paste material of the separator 3 contains a nonionic fluorine-containing surfactant having a hydrophobic group and a hydrophilic group. .
[Selection] Figure 1

Description

  The present invention relates to a manganese dry battery, and more particularly to a separator thereof.

  Conventionally, manganese dry batteries have been widely used as power sources for electronic devices such as portable devices and information devices, and portable electric lamps.

  Manganese batteries may cause a liquid leakage phenomenon in which the electrolyte leaks to the outside during storage or discharge reaction. As described below, the liquid leakage is roughly divided into three phenomena.

  The first liquid leakage phenomenon is a phenomenon in which a hole opens in the zinc can during battery storage, and the electrolyte leaks from the hole. When manganese dioxide is used as the positive electrode active material, especially naturally produced manganese dioxide containing a large amount of impurities, nickel, cobalt, copper, etc. eluted in the electrolyte react with the negative electrode zinc, causing corrosion while generating hydrogen gas. . When the corrosion reaction further proceeds, the zinc can has a hole, and the electrolyte leaks from the hole.

  The second liquid leakage phenomenon is a phenomenon in which a hole is opened in the zinc can during discharge (the zinc can is consumed), and the electrolyte leaks from the hole. The zinc can also serves as a container together with the negative electrode active material. Usually, the electric capacity of the negative electrode zinc is larger than the electric capacity of the positive electrode mixture. However, when the battery is discharged, the crystal grain boundary on the surface of the zinc can is the starting point of the reaction, and the reaction proceeds so as to expand from there. As a result, it is considered that holes are formed where the reaction of the zinc can is concentrated.

The third liquid leakage phenomenon is not a hole in the zinc can, but a large amount of electrolyte that has moved from the positive electrode mixture during discharge overflows to the outside of the battery. When the battery is discharged, the reacted Zn ²⁺ diffuses into the positive electrode mixture through the separator, but the diffusion is inhibited by the ZnCl ₂ · 4Zn (OH) ₂ generated as the reaction proceeds, and the Zn ²⁺ concentration in the vicinity of the negative electrode zinc Is significantly higher. As a result, the electrolyte solution in the positive electrode mixture moves due to the osmotic pressure, and a large amount of electrolyte solution accumulates in the air chamber portion above the battery. And leak.

  As a means for preventing the first liquid leakage phenomenon, a method of adding a surfactant to the positive electrode mixture has been proposed (see Patent Document 1). As means for preventing the second liquid leakage phenomenon, specific metal addition to a zinc can (see Patent Document 2) and control of the crystal grain size of zinc (see Patent Document 3) are disclosed.

JP-A-8-88010 JP 2008-171762 A JP 2008-198411 A

  However, the study on the technique for preventing the third liquid leakage phenomenon is short, and no effective solution has been found yet. In addition, due to the need for higher performance of batteries, this third liquid leakage phenomenon becomes prominent when the number of air chambers is reduced or the amount of electrolyte is increased, so the significance of finding effective solutions has increased. It was.

  Therefore, in the present invention, the third liquid leakage phenomenon is prevented, that is, not due to the opening of holes due to corrosion or wear of the zinc can, but a large amount of electrolyte moved from the positive electrode mixture during the discharge reaction is The object is to provide a manganese dry battery with improved leakage prevention by eliminating the phenomenon of leakage to the outside of the battery when the amount of mobile electrolyte increases compared to the volume of the air chamber. .

  To achieve the above object, the present invention provides a bottomed cylindrical negative electrode zinc can, a positive electrode mixture containing manganese dioxide, carbon powder, and electrolyte contained in the negative electrode zinc can, the negative electrode zinc can and the positive electrode In a manganese dry battery equipped with a separator disposed between the mixture and coated with a paste material, a nonionic fluorocarbon surfactant having a hydrophobic group and a hydrophilic group is added to the paste paste material of the separator. By doing so, the above object is achieved.

  According to the present invention, a large amount of the electrolyte that has moved from the positive electrode mixture during the discharge reaction is accumulated in the air chamber portion at the top of the battery, and leaks to the outside of the battery when the amount of the moving electrolyte increases compared to the air chamber volume. The effect of eliminating the phenomenon and improving prevention of liquid leakage is achieved.

It is the front view which showed a partial cross section of the single 1 type | mold manganese dry battery which concerns on this invention.

  The present invention provides a bottomed cylindrical negative electrode zinc can, a positive electrode mixture containing manganese dioxide, carbon powder, and electrolyte contained in the negative electrode zinc can, and disposed between the negative electrode zinc can and the positive electrode mixture. In the manganese dry battery including the separator coated with the paste material, the separator paste material includes a nonionic fluorocarbon surfactant having a hydrophobic group and a hydrophilic group. .

By adding a nonionic fluorocarbon surfactant to the separator paste, a large amount of electrolyte that moves as the discharge reaction proceeds can be prevented from concentrating in the vicinity of the negative electrode zinc. The amount of electrolyte accumulated in the portion is reduced, and the electrolyte is prevented from leaking out of the battery. Fluorocarbon-based hydrophobic groups generally have a lower free energy than hydrocarbon-based hydrophobic groups, so that they are excellent in water repellency and are effective in small amounts. Further, since the nonionic hydrophilic group does not inhibit the diffusion of Zn ²⁺ dissolved by the discharge reaction, it is possible to prevent the electrolytic solution from concentrating near the negative electrode zinc.

Specifically, the hydrophobic group of the nonionic fluorocarbon surfactant is a fluorocarbon group represented by the general formula: CF ₃ (CF ₂ ) _n CH ₂ —, and n is 1 or more and 10 or less. That's fine.

The hydrophilic group of the nonionic fluorocarbon surfactant is represented by a general formula: — (CH ₂ CH ₂ O) _m H, and m may be 1 or more and 50 or less.

The hydrophilic group of the nonionic fluorine-containing surfactant is represented by the general formula: — (CH ₂ CH ₂ CH ₂ O) _p H, and p may be 1 or more and 50 or less.

The hydrophilic group of the nonionic fluorine-containing surfactant is represented by the general formula: — (CH ₂ CH ₂ O) _m (CH ₂ CH ₂ CH ₂ O) _p H, and m + p is 2 or more and 50. It is good also as follows.

  The addition amount of the nonionic fluorocarbon surfactant is desirably in the range of 0.01 to 5.0% by mass with respect to the paste in the dry state. When the addition amount is 0.01% or more, it is easy to obtain a substantial effect, and when the addition amount is 5.0% by mass or more, it is difficult to obtain an increase in the effect corresponding to the increase in addition.

  Hereinafter, an embodiment of the manganese dry battery of the present invention will be described with reference to FIG. FIG. 1 is a front view, partly in section, of a single-type manganese dry battery (R20).

  A cylindrical positive electrode mixture 1 is accommodated in a bottomed cylindrical negative electrode zinc can 4. A separator 3 is disposed between the positive electrode mixture 1 and the negative electrode zinc can 4. The separator 3 is arranged so that the surface on which the paste material is applied faces the negative electrode zinc can 4. The separator 3 contains an electrolytic solution. As the electrolytic solution, for example, an aqueous solution containing zinc chloride is used. A positive electrode current collector 2 is inserted into the hollow portion of the positive electrode mixture 1.

  For the positive electrode mixture 1, for example, a mixture of powdered manganese dioxide, a carbon powder conductive agent such as acetylene black, and an electrolytic solution is used. The content of manganese dioxide in the positive electrode mixture 1 is preferably 40 to 60% by weight. The content of the carbon powder in the positive electrode mixture 1 is preferably 5 to 15% by weight.

  The resin-made gasket 5 has a cylindrical positive electrode current collector 2 inserted in a hole in the center thereof. In order to ensure hermeticity in the contact portion of the positive electrode current collector 2 with the hole of the gasket 5 and the contact portion between the groove on the lower surface of the outer peripheral portion of the gasket 5 and the open end of the negative electrode zinc can 4, A sealing agent such as polybutene is applied. A circular paper 9 having an opening is disposed on the positive electrode mixture 1, and the positive electrode current collector 2 is inserted into the opening of the paper 9.

  The opening of the negative electrode zinc can 4 is covered with a gasket 5 and a positive electrode terminal 11 made of a cap-shaped tin plate having a convex portion at the center portion and a flat plate-like flange portion around the convex portion. The top of the positive electrode current collector 2 is fitted with a concave portion formed inside the convex portion of the positive electrode terminal 11 and is electrically connected. A resin-made insulating ring 12 is disposed on the flat collar portion of the positive electrode terminal 11. In order to ensure insulation between the bottom of the positive electrode mixture 1 and the bottom of the negative electrode zinc can 4, a bottom paper 13 is provided between them. 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 tube 8 made of a heat-shrinkable resin is disposed on the outer periphery of the negative electrode zinc can 4, the upper end portion of the resin tube 8 covers the upper surface of the outer peripheral portion of the gasket 5, and the lower end portion of the resin tube 8 is the lower surface of the seal ring 7. Cover.

  A metal outer can 10 made of a cylindrical tin plate is disposed outside the resin tube 8, and its lower end is bent inward so as to cover the seal ring 7. Further, the manganese dry battery is hermetically sealed by curling the upper end of the metal outer can 10 inward and caulking the tip of the upper end to the positive electrode terminal 11 via the insulating ring 12.

Examples of the present invention will be described in detail below, but the present invention is not limited to these examples.
Example 1
On one side of kraft paper (thickness: 0.08 mm, PBD70 manufactured by Nippon Kogyo Paper Industries), a binder mainly composed of cross-linked starch (SELEX manufactured by NITTO Chemical Co., Ltd.) and vinyl acetate (Corporation manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) Neil), and a non-ionic fluorocarbon surfactant, a paste paste in which CF ₃ (CF ₂ ) ₅ CH ₂ (CH ₂ CH ₂ O) ₃₀ H was dispersed in water was applied and dried. A thing was used. As for the preparation of the paste material, the proportion of the paste material after drying is 86.5% by mass of the crosslinked starch, 13.0% by mass of the binder mainly composed of vinyl acetate, and 0.5% of the nonionic fluorocarbon surfactant. It was made to become mass%. Moreover, the amount of the paste material applied to the kraft paper was applied so that the paste material after drying was 40 g / m ² . Using the separator 3 described above, a single-type manganese dry battery (R20) of the present invention shown in FIG. 1 was produced and evaluated. In addition, it comprised so that the adhesive material of the separator 3 might closely_contact | adhere to the inner surface of the negative electrode zinc can 4. FIG.

Example 2
In the same manner as in Example 1, a separator was produced using CF ₃ (CF ₂ ) ₅ CH ₂ (CH ₂ CH ₂ CH ₂ O) ₃₀ H as a nonionic fluorocarbon surfactant. The production of the battery is the same as in Example 1.

Example 3
In the same production method as in Example 1, CF ₃ (CF ₂ ) ₅ CH ₂ (CH ₂ CH ₂ O) ₁₅ (CH ₂ CH ₂ CH ₂ O) ₁₅ H was used as a nonionic fluorocarbon surfactant. A separator was prepared using this method. The production of the battery is the same as in Example 1.

  The nonionic fluorocarbon surfactant used in this example is available from, for example, AGC Seimi Chemical Co., Ltd., and is manufactured and sold under a trade name such as Surflon S-386.

<Conventional example>
A separator was produced by the same production method as in Example 1 using the fluorosurfactant F (CF ₂ ) ₈ CH ₂ CH ₂ SO ₃ H used in Patent Document 1. The production of the battery is the same as in Example 1.

《Comparative example》
In the same production method as in Example 1, without adding a nonionic fluorocarbon surfactant, the proportion of the paste after drying was 87.0% by mass of cross-linked starch and a binder mainly composed of vinyl acetate. The separator was produced so that it might become 13.0 mass% of agents. The production of the battery is the same as in Example 1.

  In order to evaluate the phenomenon that a large amount of electrolyte moved from the positive electrode mixture during the discharge reaction is accumulated in the air chamber part at the top of the battery and leaks to the outside of the battery when the amount of mobile electrolyte increases compared to the air chamber volume. For each battery, 10 batteries were continuously discharged with a load of 2.2Ω, and the number of batteries in which electrolyte leakage occurred within 24 hours was examined. The results are shown in Table 1.

  As a result, the batteries of Examples 1 to 3 did not leak. The battery of the conventional example is not a nonionic fluorocarbon surfactant, and the battery of the comparative example has no addition of surfactant, so a large amount of electrolyte that moves from the positive electrode mixture as the discharge reaction progresses The effect of water repellency was not obtained and liquid leakage occurred. Thus, when the separator containing the fluorocarbon surfactant of the present invention is used, the liquid leakage phenomenon can be suppressed extremely effectively.

  The manganese dry battery of the present invention is suitably used as a power source for electronic devices such as portable devices and portable electric lights.

DESCRIPTION OF SYMBOLS 1 Positive electrode mixture 2 Positive electrode collector 3 Separator 4 Negative electrode zinc can 5 Gasket 6 Negative electrode terminal 7 Seal ring 8 Resin tube 9 Paperboard 10 Metal exterior can 11 Positive electrode terminal 12 Insulation ring 13 Bottom paper

Claims (6)

A bottomed cylindrical negative electrode zinc can,
A positive electrode mixture containing manganese dioxide, carbon powder, and an electrolytic solution housed in the negative electrode zinc can;
In a manganese dry battery provided with a separator disposed between the negative electrode zinc can and the positive electrode mixture and coated with a paste material, a nonionic fluorine carbide having a hydrophobic group and a hydrophilic group in the paste paste material of the separator Manganese battery containing an organic surfactant. 2. The nonionic fluorocarbon surfactant has a hydrophobic group represented by a general formula: CF ₃ (CF ₂ ) _n CH ₂ —, and n is 1 or more and 10 or less. The manganese dry battery described. 2. The nonionic fluorine-containing surfactant has a hydrophilic group represented by a general formula: — (CH ₂ CH ₂ O) _m H, and m is 1 or more and 50 or less. The manganese dry battery described. The nonionic fluorocarbon surfactant has a hydrophilic group represented by a general formula: — (CH ₂ CH ₂ CH ₂ O) _p H, and p is 1 or more and 50 or less. Item 2. A manganese dry battery according to item 1. In the nonionic fluorocarbon surfactant, the hydrophilic group is represented by the general formula: — (CH ₂ CH ₂ O) _m (CH ₂ CH ₂ CH ₂ O) _p H, and m + p is 2 or more and 50 or less. The manganese dry battery according to claim 1, wherein:   The manganese according to any one of claims 1 to 5, wherein the nonionic fluorocarbon surfactant is added in an amount of 0.01 to 5.0 mass% with respect to the dry paste. Dry cell.