JP2006164862A - Alkaline battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an alkaline battery which has excellent discharge characteristics on heavy load and light load. <P>SOLUTION: In an alkaline battery having a positive electrode containing manganese dioxide and graphite powder, the above-mentioned positive electrode contains at least one member selected from a group composed with titanium nitride (TiN) and cobalt sesquioxide (Co<SB>2</SB>O<SB>3</SB>) as an additive. An amount of the above-mentioned additive is preferably 0.05-5 parts by weight relative to 100 parts by weight of the manganese dioxide. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an alkaline battery including a positive electrode using manganese dioxide as an active material and an alkaline electrolyte.

  In recent years, applications of primary batteries such as alkaline manganese batteries have been expanded, and applications requiring high load discharge performance, such as digital still cameras, have increased. For such market needs, for example, as in Patent Document 1, anatase-type titanium oxide or a composite oxide mainly composed of titanium oxide is used as a positive electrode additive, thereby improving the reaction efficiency of the positive electrode. And a method for improving the heavy load discharge performance has been proposed.

Further, for example, as in Patent Document 2, as a positive electrode additive, a titanium silicon composite oxide represented by Ti _x Si _(1-x) O ₂ (where 0.5 ≦ x <1) or TiO (OH ) The use of ₂ has also been proposed as a method for suppressing the deterioration of light load discharge characteristics.
Japanese translation of PCT publication No. 8-510355 JP 2002-367614 A

  In the alkaline battery using the conventional positive electrode additive as described above, although the heavy load discharge characteristic is improved, there is a problem that the light load discharge characteristic is deteriorated. Since the alkaline battery is a general-purpose battery that is sometimes used at a low load such as a watch like a conventional manganese battery, it is very inconvenient that the light-load discharge characteristics deteriorate.

To solve the above problem, an alkaline battery of the present invention, the positive electrode of manganese dioxide as an active material, comprising a negative electrode and an alkaline electrolyte, wherein the positive electrode, a titanium nitride (TiN) and trioxide cobalt (Co ₂ O ₃ ) It contains at least one additive selected from the group consisting of:
Here, the positive electrode preferably contains 0.05 to 5 parts by weight of the additive per 100 parts by weight of manganese dioxide.

  Titanium nitride and dicobalt trioxide improve the conductivity in the positive electrode mixture, contribute to improving the permeability of the electrolytic solution, and reduce polarization during heavy load discharge. This improves not only the heavy load discharge characteristics but also the low load discharge characteristics.

  ADVANTAGE OF THE INVENTION According to this invention, the alkaline battery which was excellent in the heavy load discharge characteristic and also improved the light load discharge characteristic rather than the conventional alkaline battery can be provided.

The alkaline battery of the present invention includes a negative electrode, an alkaline electrolyte, and a positive electrode including manganese dioxide and graphite powder, and the positive electrode includes at least one selected from the group consisting of titanium nitride and dicobalt trioxide. It is characterized by that.
The negative electrode is preferably an alloy powder containing zinc as a main component and a gel zinc negative electrode formed by a gelling agent. However, any metal that shows a base potential in an aqueous alkaline solution and can be discharged and is stable and has other metals and organic or inorganic additives added to the metal for corrosion resistance and stability. May be.
The electrolytic solution is preferably an alkaline aqueous solution mainly composed of potassium hydroxide. Sodium hydroxide, lithium hydroxide, or calcium hydroxide may be included.

  The positive electrode active material is preferably made of manganese dioxide as a main component. For example, other metal peroxides such as nickel oxyhydroxide, metal oxides, or metal hydroxides may be contained in a small amount or as a main component. As the conductive agent for the positive electrode, it is preferable to use graphite powder. Other carbon-based conductive agents may be included.

It is preferable to interpose a nonwoven fabric such as an alkali-resistant synthetic resin as a separator between the positive electrode and the negative electrode. In addition, you may use what permeate | transmits electrolyte solution, such as a porous film.
Generally, a battery using a cylindrical case in which iron is plated is generally used as the battery exterior. However, the material may be a synthetic resin, and the shape is not specified.

  The positive electrode preferably contains 0.05 to 5 parts by weight of the additive per 100 parts by weight of manganese dioxide. If the addition amount is less than 0.05 parts by weight, the improvement of the heavy load and light load discharge characteristics is insufficient, and if it is more than 5 parts by weight, the filling amount of the positive electrode active material and the like decreases, resulting in a heavy load. Discharge and light load discharge characteristics deteriorate. This is because the additive particles are bulkier than manganese dioxide, which is the main active material, and therefore the total amount of the mixture is reduced in the positive electrode mixture formed to have a constant volume under a constant pressure. It is done. However, if the amount of the additive is in the range of 0.05 to 5 parts by weight per 100 parts by weight of manganese dioxide, the manganese dioxide particles and the additive particles are mixed well, so the filling amount of the positive electrode active material does not decrease. .

INDUSTRIAL APPLICABILITY The present invention can provide an alkaline battery that is excellent in heavy load discharge characteristics and has improved light load discharge characteristics over conventional alkaline batteries.
Embodiments of the present invention will be described below.

Embodiment 1
A zinc alloy containing 30 ppm of Al, 200 ppm of Bi, and 400 ppm of In and an electrolytic solution composed of 40 wt% KOH aqueous solution is mixed and stirred to produce gelled zinc. On the other hand, electrolytic manganese dioxide and graphite powder are mixed at a weight ratio of 9: 1, and 1 part by weight of TiN is further added per 100 parts by weight of manganese dioxide, followed by forming a positive electrode mixture. These negative electrode and positive electrode are combined with a separator made of a non-woven fabric of an alkaline electrolyte and a synthetic resin, and are placed in a positive electrode case and sealed to produce an alkaline battery.

Embodiment 2
Electrolytic manganese dioxide and graphite powder are mixed at a weight ratio of 9: 1, and 1 part by weight of Co ₂ O ₃ is further added per 100 parts by weight of manganese dioxide, followed by molding to prepare a positive electrode mixture. Otherwise, the alkaline battery is fabricated in the same manner as in the first embodiment.

Hereinafter, although the more concrete Example of this invention is described, this invention is not limited only to these.
FIG. 1 is a front view showing a cross section of a part of an alkaline battery produced in an example of the present invention. In FIG. 1, a positive electrode mixture 2, a separator 4, and a gelled negative electrode 3 formed in a short cylindrical pellet shape are accommodated in a battery case 1. As the battery case 1, a steel case having an inner surface plated with nickel can be used. On the inner surface of the battery case 1, a plurality of positive electrode mixtures 2 are accommodated in close contact. A separator 4 is disposed further inside the positive electrode mixture 2, and a gelled negative electrode 3 is further filled therein.

  The positive electrode mixture 2 was produced as follows. First, manganese dioxide, graphite, and an alkaline electrolyte were mixed at a weight ratio of 90: 10: 3, and the resulting mixture was sufficiently stirred and then compression-molded into flakes. Next, the flaky positive electrode mixture is pulverized to form a granular positive electrode mixture, which is classified by a sieve, and a 10-100 mesh one is pressure-formed into a hollow cylindrical shape to form a pellet-shaped positive electrode mixture 2 Got. Two of these positive electrode mixtures were inserted into the battery case 1, and the positive electrode mixture 2 was remolded by a pressure jig and brought into close contact with the inner wall of the battery case 1. For any positive electrode of the example, the molding pressure was produced under the same conditions, and the amount of the positive electrode mixture in each example was adjusted so that the height of the molded positive electrode mixture was the same.

  A bottomed cylindrical separator 4 was placed in the center of the positive electrode mixture 2 placed in the battery case 1 as described above, and a predetermined amount of alkaline electrolyte was injected into the separator 4. After a predetermined time, a gelled negative electrode 3 made of an alkaline electrolyte, a gelling agent, and a zinc alloy powder was filled into the separator 4.

  As the gelled negative electrode 3, a gel composed of 1 part by weight of sodium polyacrylate as a gelling agent, 33 parts by weight of a 40% by weight aqueous solution of potassium hydroxide and 66 parts by weight of zinc powder was used. Moreover, the separator 4 used the nonwoven fabric which mixed and mixed mainly the polyvinyl alcohol fiber and the rayon fiber.

  Subsequently, the negative electrode current collector 6 was inserted into the center of the gelled negative electrode 3. The negative electrode current collector 6 was integrated with a gasket 5 and a bottom plate 7 that also served as a negative electrode terminal. And the opening edge part of the battery case 1 was crimped to the peripheral part of the bottom plate 7 via the edge part of the gasket 5, and the opening part of the battery case 1 was sealed. Finally, the outer surface of the battery case 1 was covered with the exterior label 8 to obtain an alkaline battery.

Example 1
Manganese dioxide and graphite powder were mixed at a weight ratio of 9: 1, and 1.0 part by weight of TiN was added to 100 parts by weight of manganese dioxide to prepare a positive electrode mixture. Using this positive electrode mixture, an alkaline battery having the structure shown in FIG. 1 was produced.

Example 2
An alkaline battery was fabricated in the same manner as in Example 1 except that a positive electrode mixture to which Co ₂ O ₃ was added instead of TiN was used.

<< Comparative Example 1 >>
An alkaline battery was produced in the same manner as in Example 1 except that a mixture of manganese dioxide and graphite powder (weight ratio 9: 1) was used as the positive electrode mixture.

<< Comparative Example 2 >>
An alkaline battery was produced in the same manner as in Example 1 except that a positive electrode mixture in which anatase TiO ₂ was added instead of TiN was used.

<< Comparative Example 3 >>
An alkaline battery was produced in the same manner as in Example 1 except that a positive electrode mixture to which TiO (OH) ₂ was added instead of TiN was used.

<< Comparative Example 4 >>
An alkaline battery was fabricated in the same manner as in Example 1 except that a positive electrode mixture to which a titanium silicon composite oxide represented by Ti _0.95 Si _0.05 O ₂ was added instead of TiN was used.

  In order to evaluate the heavy load discharge characteristics of the battery, 10 batteries at the first time (immediately after fabrication and after standing for 1 week at room temperature) were continuously discharged at a load of 1Ω and a final voltage of 0.9 V, and the discharge time at that time was determined. The average value was measured. The result of the alkaline battery (Comparative Example 1) to which no additive was added was taken as 100 as a reference, and the heavy load discharge characteristics were expressed as an index. The light load discharge characteristics were obtained by continuously discharging at a load of 39Ω and a final voltage of 0.9 V, measuring the discharge time at that time, and obtaining the average value. These results are shown in Table 1.

From Table 1, the batteries of Examples 1 and 2 in which TiN or Co ₂ O ₃ was added to the positive electrode mixture had improved heavy load discharge characteristics as compared with the battery of Comparative Example 1 in which they were not added, The light load discharge characteristics are also higher than those of the batteries of Comparative Examples 1 to 4. On the other hand, the batteries of Comparative Examples 2 to 4 have improved strong and heavy load discharge characteristics as compared with Comparative Example 1, but the light load discharge characteristics are slightly reduced or substantially the same.
From the above results, it can be seen that according to the present invention, an alkaline battery excellent in heavy load discharge characteristics and light load discharge characteristics can be obtained.

  In the above example, the amount of additive added to the mixture of manganese dioxide and graphite powder (weight ratio 9: 1) was 1.0 part by weight per 100 parts by weight of manganese dioxide. Next, the test was performed by changing the amount of the additive within the range shown in Table 2. The results are shown in Table 2.

As can be seen from Table 2, the effect was obtained when any additive of the present invention was added in an amount of 0.05 to 5 parts by weight per 100 parts by weight of manganese dioxide. Further, TiN, although either the Co ₂ O ₃ only shows an embodiment of adding to the positive electrode, is also effective when used as a mixture of both of them, in which case the amount of both In the range of 0.05 to 5 parts by weight per 100 parts by weight of manganese dioxide.

  ADVANTAGE OF THE INVENTION According to this invention, the alkaline battery excellent in the heavy load discharge characteristic and the light load discharge characteristic can be provided. Therefore, the present invention is useful for alkaline primary batteries that meet market needs.

It is the front view which made a part of alkaline battery concerning the example of the present invention a section.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Battery case 2 Positive electrode mixture 3 Gel-like negative electrode 4 Separator 5 Gasket 6 Negative electrode current collector 7 Bottom plate 8 Exterior label

Claims (2)

  An alkaline battery comprising a positive electrode comprising manganese dioxide and graphite powder, a negative electrode, and an alkaline electrolyte, wherein the positive electrode contains at least one additive selected from the group consisting of titanium nitride and dicobalt trioxide. An alkaline battery characterized by that.   The alkaline battery according to claim 1, wherein the positive electrode contains 0.05 to 5 parts by weight of the additive per 100 parts by weight of manganese dioxide.

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