JPH0745272A - Manganese dry battery - Google Patents

Abstract

PURPOSE:To attain low public pollution by controlling Ni, Co and Cr to a specific limit amount or less, of impurities contained in a positive electrode compound, and containing bismuth of specific amount or more in a negative electrode zinc alloy, so as to suppress corrosion of the negative electrode alloy. CONSTITUTION:A positive electrode compound 1 is prepared by using manganese dioxide as an active material mixed with pulverized carbon, electrolyte, etc. As this compound 1, a sum of contents of Ni, Co, Cr, contained as impurities, is set to 0.25wt.% or less relating to the weight of manganese dioxide which is a positive electrode active material. A zinc alloy negative electrode 2 contains bismuth of amount exceeding 0.01wt.%. In this way, corrosion resistance of the negative electrode containing no lead is improved.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a manganese dry battery,
More specifically, in a manganese dry battery using manganese dioxide as the positive electrode active material and a zinc alloy as the negative electrode, even if lead is not added to the zinc alloy, it has the same resistance to corrosion as a lead-added zinc alloy, and a low resistance. Pollution-related manganese dry battery.

[0002]

2. Description of the Related Art Zinc alloy has been used for a long time as a negative electrode can that also functions as a metal container for manganese dry batteries. The negative electrode can has an amount of more than 0.005% by weight, typically 0.1 to 0.5% by weight, for the purpose of imparting corrosion resistance to corrosion by the electrolyte solution or the positive electrode active material which is the content thereof. Zinc alloys with the addition of lead have been used.

As described above, the lead contained in the negative electrode can is harmful to the human body although it is a trace amount, and as the amount of distribution and consumption increases, the lead is mixed with industrial waste and household waste and discarded. It has become necessary to prevent environmental pollution caused by

As a countermeasure, it is strongly desired to use a zinc alloy containing no lead in a negative electrode can of a manganese dry battery. However, when evaluated as a negative electrode material for manganese dry batteries, a negative electrode can that does not contain lead is more susceptible to corrosion by the electrolyte solution and positive electrode mixture in the battery than a lead-added negative electrode can, and battery performance after long-term storage Was significantly inferior, especially in the case of batteries using natural manganese dioxide.

[0005]

DISCLOSURE OF THE INVENTION The present invention solves the problem of corrosion of such a lead-free negative electrode can, and in particular, even when natural manganese dioxide is used, the performance of the battery is deteriorated after long-term use. It is an object of the present invention to provide a low-pollution manganese dry battery that prevents the above and exhibits a performance comparable to that of a battery using a lead-added negative electrode can.

[0006]

As a result of repeated studies to solve the above-mentioned problems, the inventors of the present invention have found that such corrosion of the negative electrode alloy is particularly remarkable among impurities contained in the positive electrode mixture. The inventors have found that this can be suppressed by controlling the abundances of nickel, cobalt, and copper to be below a specific limit and by containing bismuth in excess of a specific amount in the negative electrode zinc alloy, and have completed the present invention.

That is, the manganese dry battery of the present invention is
In a manganese dry battery including (1) a positive electrode mixture containing manganese dioxide as a positive electrode active material, (2) a zinc alloy negative electrode and (3) a separator, the contents of nickel, cobalt and copper in the positive electrode mixture of (1). Of 0.25% by weight or less based on the amount of manganese dioxide in the mixture;
The zinc alloy negative electrode of (2) is characterized by containing more than 0.01% by weight of bismuth.

The positive electrode mixture (1) used in the present invention is
Manganese dioxide is used as an active material, and is prepared by mixing finely powdered carbon and an electrolytic solution. A feature of the present invention is that the total content of nickel, cobalt and copper contained as impurities in the positive electrode mixture is the amount of manganese dioxide which is the positive electrode active material contained in the positive electrode mixture as an element. To 0.25% by weight or less, preferably 0.15% by weight or less. This impurity is mainly derived from manganese dioxide as a raw material, and is present in the positive electrode mixture in the form of oxide, chloride, hydroxide, etc., but it may be present in the form of other compounds. Is the total abundance as an element. Further, as individual elements, nickel is preferably 0.10 wt% or less, cobalt is 0.10 wt% or less, and copper is 0.05 wt% with respect to manganese dioxide. When the total content of these elements in the positive electrode mixture exceeds 0.25% by weight with respect to manganese dioxide, corrosion of the zinc alloy negative electrode and accompanying generation of hydrogen gas are large.

As manganese dioxide, any one of natural manganese dioxide, electrolytic manganese dioxide, and chemically synthesized manganese dioxide can be used, but it is economically easily available, but with respect to a zinc alloy negative electrode to which lead is not added. The effect of the present invention is particularly remarkable in natural manganese dioxide, which is highly corrosive.

The second feature of the present invention is that the amount of the zinc alloy negative electrode of (2) exceeds 0.01% by weight, preferably 0.05.
The content of bismuth is about 0.8% by weight, whereby the nickel in the positive electrode mixture of the above (1),
Along with suppressing the contents of cobalt and copper to be equal to or less than a specific amount, the corrosion resistance of the negative electrode containing no lead can be improved. When the amount of bismuth in the zinc alloy negative electrode is 0.01% by weight or less, satisfactory results cannot be obtained unless lead is contained in the zinc alloy negative electrode, and corrosion of the negative electrode and accompanying generation of hydrogen gas are large. Further, even if added in excess of 0.8% by weight, an effect commensurate with the added amount cannot be expected. Such a zinc alloy negative electrode is used in the shape of, for example, a negative electrode can.

In the separator (3), the positive electrode mixture (1) and the zinc alloy negative electrode (2) do not come into direct contact with each other,
It is interposed between (1) and (2). Kraft paper is generally used as the base material. If necessary, a sizing agent containing polyvinyl alcohol, starch and / or starch derivative may be applied to the surface.

In the present invention, in addition to the above-mentioned amount of impurities in the positive electrode mixture in (1) and the amount of bismuth in the zinc alloy in (2), the bismuth compound is added to the surface of the separator in (3). The presence of the cationic surfactant and / or the cationic surfactant can further improve the effect of suppressing the corrosion of the negative electrode. Such a bismuth compound and /
Alternatively, the cationic surfactant may be added to the sizing agent as a component of the sizing agent described above, and the sizing agent may be applied to the separator substrate, or may be separately impregnated or applied as an aqueous solution to the separator substrate. Alternatively, it may be sprayed and applied.

Examples of the bismuth compound existing on the surface of such a separator include bismuth oxide, bismuth hydroxide, bismuth chloride, bismuth oxychloride, bismuth fluoride, bismuth sulfide, bismuth sulfate and bismuth nitrate. preferable. The amount of bismuth compound present on the surface of the separator, in terms of the effect of suppressing the corrosion of the negative electrode is preferably in the range of ^{0.02~0.6mg / cm 2, 0.05~0.2mg / cm} 2 and more preferable. 0.0
If it is less than 2 mg / cm ² , the corrosion inhibition effect due to the presence of the bismuth compound is not significantly improved, and if it exceeds 0.6 mg / cm ² ,
Although it has the effect of suppressing corrosion, it causes an increase in the internal resistance of the battery.

Examples of the cationic surfactant include quaternary ammonium salt type, pyridinium salt type, imidazoline quaternary salt type, isoquinolinium salt type, amine salt type and quaternary phosphonium salt type. The salt form is preferred. Examples of the quaternary ammonium salt-type cationic surfactant include dodecyltrimethylammonium chloride, tetradecyltrimethylammonium chloride, hexadecyltrimethylammonium chloride, octadecyltrimethylammonium chloride and behenyltrimethylammonium chloride, and mixtures thereof, such as natural fats and oils. Monoalkyl system having one long chain alkyl group such as beef tallow alkyltrimethylammonium chloride and coconut oil alkyltrimethylammonium chloride; tetradecylbenzyldimethylammonium chloride, octadecylbenzyldimethylammonium chloride, tallow alkylbenzyldimethylammonium chloride, palm Oil such as alkylbenzyldimethylammonium chloride A monoalkylbenzyl system having a chain alkyl group and one benzyl group; having two long chain alkyl groups or long chain alkenyl groups such as didodecyldimethylammonium chloride, distearyldimethylammonium chloride, dioleyldimethylammonium chloride A dialkyl type is illustrated, a monoalkyl type or a monoalkyl benzyl type is preferable, and a monoalkyl type is particularly preferable.

The amount of the cationic surfactant present on the surface of the separator depends on the effect of suppressing the corrosion of the negative electrode.
The range of 005-0.1 mg / cm ² is preferable, and 0.005-
0.02 mg / cm ² is more preferred. If it is less than 0.005 mg / cm ² , the corrosion inhibitory effect due to the presence of the cationic surfactant is not significantly improved, and if it exceeds 0.1 mg / cm ² , there is a corrosion inhibitory effect, but voltage deterioration and heavy load discharge It may cause deterioration of battery performance.

The coexistence of the bismuth compound and the cationic surfactant on the surface of the separator exhibits a more remarkable corrosion inhibiting effect than the case where each of them is present alone.

[0017]

INDUSTRIAL APPLICABILITY According to the present invention, a zinc alloy negative electrode containing no lead that pollutes the environment exhibits the same corrosion inhibition effect as in the case of using a conventional lead-added zinc alloy negative electrode, and therefore has the same performance, particularly It is possible to obtain a low-pollution manganese dry battery having an equivalent service life.

[0018]

EXAMPLES The present invention will be described below with reference to examples and comparative examples. In these examples, parts represent parts by weight. The invention should not be limited by these examples.

Examples 1 to 21 Preparation of Positive Electrode Mixture 60 parts of natural manganese dioxide and 10 parts of acetylene black were mixed well, and an electrolytic solution 49 which was an aqueous solution containing 25% by weight of zinc chloride and 2% by weight of ammonium chloride was mixed. A part was added and mixed uniformly to prepare a positive electrode mixture. The contents of nickel, cobalt and copper in the manganese dioxide used were as shown in Table 1 as a result of the high frequency inductively coupled plasma optical emission analysis. The acetylene black, zinc chloride and ammonium chloride used here did not contain these metal elements to the extent that they would affect the contents of nickel, cobalt and copper in the positive electrode mixture.

Preparation of Negative Electrode Can On the other hand, the amount of bismuth shown in Table 1 was added to an electrorefined zinc metal having a purity of 99.99% by weight or more and melted to obtain an alloy sample. This alloy was rolled and punched to obtain zinc alloy pellets. A mixture of flake graphite and boric acid was used as a lubricant, and the pellets were subjected to R
Processed into a 20-inch negative electrode can.

Preparation of Separator A separator using kraft paper as a base material was prepared as follows. That is, a paste paste made of an aqueous solution of polyvinyl alcohol, starch, and polyoxyethylene (15) nonylphenyl ether was prepared, and, in addition to Example 12, the amounts of bismuth oxide and / or that described in Table 1 were used. Bismuth oxide and / or octadecyltrimethylammonium chloride in an amount such that octadecyltrimethylammonium chloride was applied to kraft paper was blended into this and uniformly mixed to obtain a paste sample. The paste sample was applied to kraft paper and dried to prepare a separator.

Preparation of Manganese Dry Battery Using the positive electrode mixture 1, the negative electrode can 2 and the separator 3 obtained as described above, a carbon rod 4, a sealing body 5 and a positive electrode terminal plate which are usually used in a manganese dry battery of this kind are used. 6, the negative electrode terminal plate 7, the insulating tube 8 and the outer can 9 are used.
The R20 type manganese dry battery shown in was produced. Evaluations A, B and C were performed using these dry batteries.

Evaluation A: 300Ω continuous discharge (n = 3) The battery produced as described above was stored at 20 ° C. for 90 days, and then continuously discharged at 300 ° C. in a thermostat at 20 ° C.
The duration until reaching 9V was measured. Moreover, the maximum value of the internal resistance during the discharge was also measured.

Evaluation B: 2Ω continuous discharge (n = 3) The battery prepared as described above was heated to 2Ω in a constant temperature bath at 20 ° C.
It was continuously discharged, and the duration until reaching 0.9 V was measured.

Evaluation C: Amount of gas generated after 2Ω continuous discharge (n = 3) The battery after the continuous discharge of evaluation B was placed in an inverted graduated cylinder filled with liquid paraffin and hermetically sealed at 20 ° C.
Was stored at a constant temperature for 15 days, and the gas generated from the battery was accumulated in the upper part of the cylinder. The amount of accumulated gas was measured by the scale of a graduated cylinder.

Evaluation Results The results of the above evaluations A, B and C are summarized in Table 1.

[0027]

[Table 1]

[0028]

[Table 2]

Comparative Examples 1 to 4 Manganese dry batteries were prepared in the same manner as in Examples 1 to 21, except that natural manganese dioxide having a total content of nickel, cobalt and copper exceeding the range of the present invention was used as manganese dioxide. Was prepared and evaluated in the same manner. Table 2 shows the contents of nickel, cobalt and copper in manganese dioxide, the content of bismuth in the zinc alloy negative electrode, the amounts of the bismuth compound and the cationic surfactant on the surface of the separator, and the evaluation results.

[0030]

[Table 3]

As is clear from this result, nickel,
The manganese dry battery using the positive electrode mixture whose total content of cobalt and copper exceeds the range of the present invention is inferior in the result of the continuous discharge test of 300Ω or 2Ω to the manganese dry battery of the present invention.

Comparative Examples 5 to 8 A conventional lead-containing zinc alloy containing 0.17% by weight of lead was used as a negative electrode can, and nickel was used as manganese dioxide.
The total content of cobalt and copper is within the range of the present invention (Comparative Example 5) or exceeds the range (Comparative Examples 6 to 8) using natural manganese dioxide, and the bismuth compound and the cation are used as the sizing agent applied to the separator. Manganese dry batteries were prepared and evaluated in the same manner as in Examples 1 to 21, except that the surfactant was not added. Table 3 shows the contents of nickel, cobalt and copper in manganese dioxide, the content of bismuth in the zinc alloy negative electrode, and the evaluation results.

[0033]

[Table 4]

Comparing the evaluation results shown in Table 1 with the results shown in Table 3, the manganese dry battery of the present invention shows that the lead-containing zinc alloy is used in the negative electrode can even though the negative electrode can does not contain lead. It can be seen that it has the same discharge characteristics as the conventional manganese dry battery used as.

[Brief description of drawings]

FIG. 1 is a sectional view of a manganese dry battery.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Positive electrode mixture 2 Negative electrode can 3 Separator 4 Carbon rod 5 Sealing body 6 Positive electrode terminal plate 7 Negative electrode terminal plate 8 Insulating tube 9 Exterior can

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kojiro Miyasaka 3-4-10 Minami-Shinagawa, Shinagawa-ku, Tokyo Inside Toshiba Battery Co., Ltd.

Claims (3)

[Claims] 1. A manganese dry battery comprising (1) a positive electrode mixture containing manganese dioxide as a positive electrode active material, (2) a zinc alloy negative electrode and (3) a separator, wherein nickel and cobalt in the positive electrode mixture of (1). And the total content of copper is 0.25% by weight or less with respect to the amount of manganese dioxide in the mixture; (2) the zinc alloy negative electrode contains more than 0.01% by weight of bismuth. Manganese dry battery characterized by. 2. The manganese dry battery according to claim 1, wherein the bismuth compound is present on the surface of the separator of (3). 3. The manganese dry battery according to claim 1, wherein a cationic surfactant is present on the surface of the separator of (3).