阅读说明：本技术 碱性干电池 (Alkaline dry cell ) 是由 樟本靖幸 高桥康文 福井厚史 于 2018-10-11 设计创作，主要内容包括：碱性干电池具备：正极；负极；配置于正极与负极之间的分隔件；和,包含于正极、负极和分隔件中的碱性电解液。负极含有：包含锌的负极活性物质、和添加剂。添加剂包含选自由马来酸、马来酸酐和马来酸盐组成的组中的至少1种。(The alkaline dry battery comprises: a positive electrode; a negative electrode; a separator disposed between the positive electrode and the negative electrode; and an alkaline electrolyte contained in the positive electrode, the negative electrode, and the separator. The negative electrode contains: a negative active material including zinc, and an additive. The additive comprises at least 1 selected from the group consisting of maleic acid, maleic anhydride and a maleate salt.)

1. An alkaline dry battery comprising: a positive electrode; a negative electrode; a separator disposed between the positive electrode and the negative electrode; and an alkaline electrolyte contained in the positive electrode, the negative electrode, and the separator,

the negative electrode contains: a negative electrode active material containing zinc, and an additive,

the additive comprises at least 1 selected from the group consisting of maleic acid, maleic anhydride and a maleate salt.

2. The alkaline dry battery according to claim 1, wherein the amount of the additive contained in the negative electrode is 0.2 parts by mass or more and 4 parts by mass or less with respect to 100 parts by mass of the electrolyte contained in the negative electrode.

3. The alkaline dry battery according to claim 1 or 2, wherein the additive contains maleic anhydride.

4. The alkaline dry battery according to any one of claims 1 to 3, wherein the positive electrode contains the additive.

Technical Field

The present invention relates to an improvement in a negative electrode of an alkaline dry battery.

Background

Alkaline dry batteries (alkaline manganese dry batteries) have a larger capacity than manganese dry batteries and are widely used because they can draw a large current. The alkaline dry battery comprises: a positive electrode; a negative electrode; a separator disposed between the positive electrode and the negative electrode; and an alkaline electrolyte contained in the positive electrode, the negative electrode, and the separator. The negative electrode contains a negative electrode active material containing zinc.

However, when a plurality of alkaline dry batteries are connected in series and used in an apparatus, 1 of the alkaline dry batteries may be connected by mistake with the positive and negative being reversed and charged. In addition, an alkaline dry battery as a primary battery may be erroneously loaded in a charger for a secondary battery and charged.

When an alkaline dry battery is charged by erroneous use, hydrogen gas is generated in the battery, and the internal pressure of the battery rises. When the amount of hydrogen gas generated increases and the internal pressure of the battery reaches a predetermined value, the safety valve operates to release the hydrogen gas inside the battery to the outside. At this time, the hydrogen gas is released to the outside and the alkaline electrolyte leaks to the outside, and the alkaline electrolyte leaking to the outside may cause a failure of the apparatus.

In order to suppress leakage of alkaline electrolyte to the outside when an alkaline dry battery is charged by erroneous use, patent document 1 proposes the following: zinc oxide is added to the alkaline electrolyte.

Disclosure of Invention

When charging continues due to erroneous use of the alkaline dry battery, the precipitation of zinc by reduction of zinc ions in the electrolyte of the negative electrode proceeds, and the amount of zinc ions in the electrolyte decreases. When the zinc ions in the electrolyte are reduced, the resistance to the precipitation reaction of zinc is greatly increased, the negative electrode potential is rapidly reduced, and the hydrogen production potential can be reached at an early stage. As a result, the amount of hydrogen generated increases, and the hydrogen is released to the outside by the operation of the safety valve, and the alkaline electrolyte leaks to the outside.

One aspect of the present disclosure relates to an alkaline dry battery including: a positive electrode; a negative electrode; a separator disposed between the positive electrode and the negative electrode; and an alkaline electrolyte solution contained in the positive electrode, the negative electrode, and the separator, wherein the negative electrode contains: a negative electrode active material containing zinc, and an additive containing at least 1 selected from the group consisting of maleic acid, maleic anhydride, and a maleate salt.

According to the present disclosure, when the alkaline dry battery is charged due to erroneous use, the alkaline electrolyte can be prevented from leaking to the outside of the battery.

Drawings

Fig. 1 is a front view of an alkaline dry battery in accordance with an embodiment of the present invention, partially in section.

Detailed Description

An alkaline dry battery according to an embodiment of the present invention includes: a positive electrode; a negative electrode; a separator disposed between the positive electrode and the negative electrode; and an alkaline electrolyte (hereinafter, simply referred to as an electrolyte) contained in the positive electrode, the negative electrode, and the separator. The negative electrode contains a negative electrode active material containing zinc, and an additive. The additive comprises at least 1 selected from the group consisting of maleic acid, maleic anhydride and a maleate salt.

When the alkaline dry battery is charged by wrong use, zinc ions (Zn) contained in the electrolyte in the negative electrode²⁺) The reaction is reduced to cause precipitation of zinc on the surface of the negative electrode active material. Therefore, the potential of the negative electrode was maintained at about-1.4V (vs. Hg/HgO), which is the reduction potential of zinc ions. When the alkaline dry battery is further charged, the zinc ions in the electrolyte decrease, the resistance to the above-described precipitation reaction of zinc increases, and the negative electrode potential decreases to-1.7V (vs. The zinc ion in the electrolyte is represented by a zinc complex ion: zn (OH)₄ ^2-Exist in the form of (1).

On the other hand, when the amount of zinc ions in the electrolyte is small by including the additive in the negative electrode, the precipitation reaction of zinc is promoted, and the negative electrode potential can be delayed from reaching the hydrogen generation potential. Thus, when the alkaline dry battery is charged by erroneous use, the generation of hydrogen in the battery and the leakage of the electrolyte to the outside of the battery can be suppressed.

When the negative electrode potential is lowered by charging, the additive is reductively decomposed on the surface of the negative electrode active material, and it is presumed that a coating (SEI) is formed on the surface of the negative electrode active material. The mechanism by which the precipitation reaction of zinc is promoted when the additive is contained in the negative electrode is not clear, but it is presumed that: the coating film is one of factors that affect the precipitation reaction of zinc on the surface of the negative electrode active material.

The zinc ions contained in the electrolytic solution include, for example, a part of zinc contained in the negative electrode active material eluted in the electrolytic solution. By adding zinc oxide to the electrolyte, the amount of zinc ions contained in the electrolyte can be easily increased. The concentration of zinc oxide in the electrolyte is, for example, 1 to 5 mass%.

The additive comprises at least 1 selected from the group consisting of maleic acid, maleic anhydride and a maleate salt. A portion of the maleic acid and salts thereof may be present in the form of anions upon ionization. A portion of the maleic anhydride may be present in the form of maleic acid by hydrolysis with water in the electrolyte. Examples of the maleate salt include alkali metal salts, alkaline earth metal salts, onium salts, and ammonium salts of maleic acid. Examples of the alkali metal salt include sodium salt and potassium salt. Examples of the alkaline earth metal salt include a magnesium salt and a calcium salt.

The additive preferably contains maleic anhydride from the viewpoint of suppressing hydrogen generation when the alkaline dry battery is charged by erroneous use.

The amount of the additive contained in the negative electrode is preferably 0.2 parts by mass or more and 4 parts by mass or less with respect to 100 parts by mass of the electrolyte contained in the negative electrode. When the amount of the additive contained in the negative electrode is 0.2 parts by mass or more relative to 100 parts by mass of the electrolyte solution contained in the negative electrode, the effect of the additive on suppressing hydrogen generation can be sufficiently obtained. When the amount of the additive contained in the negative electrode is 4 parts by mass or less with respect to 100 parts by mass of the electrolyte solution contained in the negative electrode, the filling amount of the negative electrode active material can be sufficiently secured. The amount of the additive contained in the negative electrode is more preferably 1 part by mass or more and 2 parts by mass or less with respect to 100 parts by mass of the electrolyte solution contained in the negative electrode.

The positive electrode may also contain the above-described additives. The additive added to the negative electrode is substantially retained in the negative electrode, and a very small portion of the additive contained in the electrolyte in the negative electrode can migrate into the electrolyte in the positive electrode.

The negative electrode may further contain a surfactant or an aromatic compound for adjusting viscosity or the like. Examples of the surfactant include polyoxyalkylene group-containing compounds and phosphoric acid esters, and among them, phosphoric acid esters and alkali metal salts thereof are preferable. The aromatic compound is preferably terephthalic acid.

The alkaline dry battery according to one embodiment of the present invention includes a cylindrical battery, a coin battery, and the like.

The alkaline dry battery of the present embodiment will be described in detail below with reference to the drawings. The present invention is not limited to the following embodiments. Further, the present invention can be modified as appropriate within a range not departing from the scope of the present invention. Further, the present invention can be combined with other embodiments.

Fig. 1 is a front view of an alkaline dry battery according to an embodiment of the present invention, with a cross-sectional view taken along a half-cut. Fig. 1 shows an example of a cylindrical battery having an inside-out type structure. As shown in fig. 1, the alkaline dry battery includes: a hollow cylindrical positive electrode 2; a gel-like negative electrode 3 disposed in the hollow portion of the positive electrode 2; a separator 4 disposed therebetween; and an electrolyte (not shown) contained in the bottomed cylindrical battery case 1 having a positive electrode terminal as well. An aqueous alkali solution is used for the electrolyte.

The positive electrode 2 is disposed in contact with the inner wall of the battery case 1. The positive electrode 2 includes manganese dioxide and an electrolyte. A separator 4 is interposed between the hollow portions of the positive electrodes 2, and the gel-like negative electrode 3 is filled therein. The negative electrode 3 generally contains an electrolyte and a gelling agent in addition to the negative electrode active material containing zinc and the above-described additives.

The separator 4 is a bottomed cylindrical shape and contains an electrolytic solution. The separator 4 is composed of a cylindrical separator 4a and a base paper 4 b. The separator 4a is disposed along the inner surface of the hollow portion of the positive electrode 2, and separates the positive electrode 2 from the negative electrode 3. Thus, the separator disposed between the positive electrode and the negative electrode is a cylindrical separator 4 a. The base paper 4b is disposed at the bottom of the hollow portion of the positive electrode 2, and separates the negative electrode 3 from the battery case 1.

The opening of the battery case 1 is sealed by a sealing unit 9. The sealing unit 9 is composed of a gasket 5, a negative electrode terminal plate 7 serving as a negative electrode terminal, and a negative electrode current collector 6. The negative electrode current collector 6 is inserted into the negative electrode 3. The negative electrode current collector 6 has a nail-like shape having a head portion and a body portion, the body portion is inserted into a through hole provided in the central cylindrical portion of the gasket 5, and the head portion of the negative electrode current collector 6 is welded to a flat portion in the central portion of the negative electrode terminal plate 7. The opening end of the battery case 1 is fitted to the flange of the peripheral edge of the negative electrode terminal plate 7 via the outer peripheral end of the gasket 5. The outer surface of the battery case 1 is covered with an exterior label 8.

The alkaline dry battery will be described in detail below.

(cathode)

Examples of the negative electrode active material include zinc and zinc alloy. The zinc alloy may include at least one selected from the group consisting of indium, bismuth, and aluminum from the viewpoint of corrosion resistance. The zinc alloy contains 0.01 to 0.1 mass% of indium and 0.003 to 0.02 mass% of bismuth, for example. The content of aluminum in the zinc alloy is, for example, 0.001 to 0.03 mass%. From the viewpoint of corrosion resistance, the content of elements other than zinc in the zinc alloy is preferably 0.025 to 0.08 mass%.

The negative electrode active material is usually used in a powdery form. The average particle diameter (D50) of the negative electrode active material powder is, for example, 100 to 200 μm, preferably 110 to 160 μm, from the viewpoint of the filling property of the negative electrode and the diffusibility of the electrolyte in the negative electrode. In the present specification, the average particle diameter (D50) refers to a median particle diameter in a volume-based particle size distribution. The average particle diameter can be determined, for example, by a laser diffraction/scattering particle distribution measuring apparatus.

The negative electrode can be obtained, for example, by mixing negative electrode active material particles containing zinc, the above-described additive, a gelling agent, and an electrolytic solution.

As the gelling agent, known gelling agents used in the field of alkaline dry batteries can be used without particular limitation, and for example, water-absorbent polymers and the like can be used. Examples of such gelling agents include polyacrylic acid and sodium polyacrylate.

The amount of the gelling agent added is, for example, 0.5 to 2.5 parts by mass per 100 parts by mass of the negative electrode active material.

A surfactant or an aromatic compound may be added to the negative electrode for adjusting viscosity or the like. The surfactants and aromatic compounds exemplified above can be used. From the viewpoint of dispersing the surfactant and the aromatic compound more uniformly in the negative electrode, it is preferable to add the surfactant and the aromatic compound in advance to the electrolyte solution used in the production of the negative electrode.

In order to improve corrosion resistance, a compound containing a metal having a high hydrogen overvoltage, such as indium or bismuth, may be added to the negative electrode as appropriate. In order to suppress the growth of dendrites such as zinc oxide, a small amount of silicic acid compound such as silicic acid or its potassium salt may be added to the negative electrode as appropriate.

(negative electrode collector)

Examples of the material of the negative electrode current collector inserted into the gel-like negative electrode include a metal, an alloy, and the like. The negative electrode current collector preferably contains copper, and may be made of an alloy containing copper and zinc, such as brass. The negative electrode current collector may be subjected to plating treatment such as tin plating, if necessary.

(Positive electrode)

The positive electrode usually contains a conductive agent and an electrolyte in addition to manganese dioxide as a positive electrode active material. The positive electrode may further contain a binder as necessary.

As manganese dioxide, electrolytic manganese dioxide is preferred. The crystal structure of manganese dioxide includes α -type, β -type, γ -type, η -type, λ -type, and ramsdellite-type.

Manganese dioxide is used in the form of powder. The average particle diameter (D50) of manganese dioxide is, for example, 25 to 60 μm, from the viewpoint of easily ensuring the filling property of the positive electrode and the diffusibility of the electrolyte in the positive electrode.

From the viewpoint of formability and suppression of expansion of the positive electrode, the BET specific surface area of manganese dioxide may be, for example, 20 to 50m²(ii) a range of/g. The BET specific surface area is obtained by measuring and calculating the surface area using the BET formula, which is a theoretical formula of adsorption of the monolayer. The BET specific surface area can be measured, for example, by a specific surface area measuring apparatus based on a nitrogen adsorption method.

Examples of the conductive agent include carbon black such as acetylene black, and conductive carbon materials such as graphite. As the graphite, natural graphite, artificial graphite, or the like can be used. The conductive agent may be in the form of a fiber or the like, but is preferably in the form of a powder. The average particle diameter (D50) of the conductive agent is, for example, 3 to 20 μm.

The content of the conductive agent in the positive electrode is, for example, 3 to 10 parts by mass, preferably 5 to 9 parts by mass, based on 100 parts by mass of manganese dioxide.

Silver or Ag may be added to the positive electrode in order to absorb hydrogen generated in the alkaline dry battery when the battery is charged by wrong use₂O、AgO、Ag₂O₃、AgNiO₂And the like.

The positive electrode can be obtained, for example, as follows: the positive electrode material mixture is obtained by pressing a positive electrode material mixture containing a positive electrode active material, a conductive agent, an alkaline electrolyte, and a binder as needed into a pellet form. The positive electrode mixture may be once formed into a sheet or a pellet, classified as necessary, and then press-molded into a pellet form.

After the pellets are contained in the battery case, secondary pressurization can be performed by a predetermined tool so as to be in close contact with the inner wall of the battery case.

(spacer)

Examples of the material of the separator include cellulose and polyvinyl alcohol. The separator may be a nonwoven fabric mainly composed of fibers of the above-mentioned materials, or may be a microporous film such as cellophane or polyolefin film. Nonwoven fabrics may also be used in combination with the microporous film. Examples of the nonwoven fabric include a nonwoven fabric obtained by blending mainly cellulose fibers and polyvinyl alcohol fibers, and a nonwoven fabric obtained by blending mainly rayon fibers and polyvinyl alcohol fibers.

In fig. 1, a cylindrical separator 4 with a bottom is configured by using a cylindrical separator 4a and a base paper 4 b. The separator having a bottomed cylindrical shape is not limited to this, and a separator having a known shape used in the field of alkaline dry batteries may be used. The separator may be formed of 1 sheet, and a plurality of sheets may be stacked as long as the sheet constituting the separator is thin. The cylindrical separator may be formed by winding a thin sheet a plurality of times.

The thickness of the separator is, for example, 200 to 300 μm. The separator preferably has the above thickness as a whole, and a plurality of sheets may be stacked to have the above thickness as long as the sheet constituting the separator is thin.

(electrolyte)

The electrolyte is contained in the positive electrode, the negative electrode, and the separator. As the electrolytic solution, for example, an alkaline aqueous solution containing potassium hydroxide is used. The concentration of potassium hydroxide in the electrolyte is preferably 30 to 50 mass%. The electrolyte may further contain zinc oxide. The concentration of zinc oxide in the electrolyte is, for example, 1 to 5 mass%.

(pad)

Examples of the material of the gasket include polyamide, polyethylene, polypropylene, and the like. The gasket can be obtained by injection molding the above-described material into a predetermined shape, for example. The material of the gasket is preferably 6, 10-nylon, 6, 12-nylon, or polypropylene, from the viewpoint of easy permeation of hydrogen. The gasket generally has a thin portion for explosion prevention. In order to increase the hydrogen permeability, the thin wall portion is preferably provided in an annular shape. The gasket 5 of fig. 1 has an annular thin portion 5 a.

(Battery case)

For example, a metal case having a bottomed cylindrical shape is used as the battery case. For example, a nickel-plated steel sheet is used for the metal case. In order to improve the adhesion between the positive electrode and the battery case, it is preferable to use a battery case in which the inner surface of the metal case is covered with a carbon coating film.