JPH11185772A - Manganese dry battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a low load discharge characteristic and a pulse discharge characteristic in the time of the low load discharging of a manganese dry battery. SOLUTION: The discharge characteristic can be improved by adding and mixing a titanate in at least one of a positive electrode mixture 1 of a manganese dry battery and glue of a separator 4. Preferably, the titanate is alkaline- earth metal salt, and the additive quantity is set to be 0.2-0.6 pts.wt. to electrolytic manganese dioxide or powdered synthetic manganese dioxide 100 pts.wt. that are a positive electrode active material, or to the glue 100 pts.wt. of the separator 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in pulse discharge characteristics of a manganese dry battery at light load and medium load discharge.

[0002]

2. Description of the Related Art In a manganese dry battery, manganese dioxide is used as a positive electrode active material, a zinc alloy is used as a negative electrode active material, and a zinc chloride-containing solution is used as an electrolytic solution. In addition, there has been a problem that the internal resistance of the battery rises and the pulse discharge characteristics in which pulse discharge is superimposed deteriorate. This is particularly remarkable in batteries in which mercury is not added for the purpose of eliminating pollution from dry batteries. Such deterioration in pulse characteristics during light load / medium load discharge has been extremely disadvantageous when used for applications such as pagers.

[0003] In order to solve this problem, conventionally, the amount of electrolyte in the positive electrode mixture has been increased, the amount of graphite as a conductive agent has been increased, or the type of paste for the separator has been changed. Was.

[0004] As manganese dioxide as a positive electrode active substance, electrolytic manganese dioxide or chemically synthesized manganese dioxide powder adjusted to a predetermined pH by neutralization using an alkaline aqueous solution of a sodium salt or ammonium salt is used. . Acetylene black was added as a conductive material to the electrolytic manganese dioxide or the chemically synthesized manganese dioxide powder, and an electrolytic solution was further added, followed by stirring and mixing to prepare a positive electrode mixture.

[0005]

However, increasing the amount of the electrolytic solution or the amount of the conductive agent decreases the amount of the manganese dioxide in the positive electrode mixture, resulting in a decrease in the discharge capacity. Leads to a decline. In addition, when the glue of the separator is changed, there is a disadvantage that characteristics such as heavy load discharge are deteriorated even if increase in internal resistance during light load / medium load discharge can be suppressed.

When the above electrolytic manganese dioxide or chemically synthesized manganese dioxide powder is used, the difference in pH affects the battery voltage, and in order to reduce this, a small amount of zinc oxide is added at the time of mixing the positive electrode mixture. Has been added.
However, the addition of zinc oxide has some effect on battery voltage control.However, if the added amount exceeds an appropriate amount, the battery performance will be adversely affected, such as a drop in battery voltage during discharge and an increase in battery internal resistance. Therefore, it is difficult to control the addition amount of zinc oxide corresponding to the pH of electrolytic manganese dioxide or chemically synthesized manganese dioxide. In particular, in the case of a dry mercury manganese dry battery, when it is used in an application in which pulse discharge is superimposed during a discharge from a light load to a medium load, there is a problem that the internal resistance increases from the middle of the discharge.

SUMMARY OF THE INVENTION The present invention has been made to solve such a conventional problem. A manganese dry battery which suppresses an increase in internal resistance during light load / medium load discharge and has a small decrease in pulse discharge characteristics, especially mercury An object is to provide a manganese dry battery without any additives.

[0008]

That is, the present invention provides a positive electrode mixture using manganese dioxide as a positive electrode active material, a zinc negative electrode, and a separator made of kraft paper coated with an adhesive layer.
In a manganese dry battery using the invention, at least one of the positive electrode mixture and the paste layer contains a titanate.

As the titanate, an alkaline earth metal salt such as a magnesium salt, a calcium salt, a barium salt and a strontium salt is preferable. The addition amount of titanate is preferably 0.2 to 0.6 parts by weight with respect to 100 parts by weight of electrolytic manganese dioxide or chemically synthesized manganese dioxide powder or 100 parts by weight of paste.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings. [Examples 1 to 5] (Preparation of positive electrode mixture) Electrolytic manganese dioxide or chemically synthesized manganese dioxide powder was washed with water and then neutralized with an aqueous solution of sodium carbonate. The pH of this manganese dioxide powder is J
It was 4.2 when measured according to IS K1467. To 100 parts by weight of this manganese dioxide powder, 0.1 parts by weight, 0.2 parts by weight, 0.4 parts by weight, 0.6 parts by weight and 0.7 parts by weight of magnesium titanate powder were added, and each was uniformly mixed. The mixture was stirred and mixed so as to be dispersed.

Using these mixtures as a positive electrode active material, a zinc can as a negative electrode active material, and a zinc chloride-based electrolyte, an R6 type anhydrous silver manganese dry battery shown in FIG. 1 was produced. In the figure, 1 is a positive electrode mixture, 2 is a carbon rod as a positive electrode current collector, 3 is a zinc can, 4 is a separator, 5 is a sealing plate, 6 is a sealing agent,
7 is a metal outer cylinder. The positive electrode mixture 1 is composed of the above mixture, acetylene black, and an electrolytic solution (ZnCl ₂ : 26 wt%,
NH ₄ Cl: 1.5 wt%) and zinc oxide in a weight ratio of 55: 8: 36: 0.4.

Comparative Example 1 Instead of the above magnesium titanate powder, magnesium aluminate (MgAl
R6 type anhydrous silver manganese dry battery was manufactured in the same manner as in Examples 1 to 5, except that ₂ O ₄ ) was mixed in an amount of 0.4 part by weight with respect to 100 parts by weight of the manganese dioxide powder.

Comparative Example 2 Example 1 was repeated except that manganese dioxide powder not mixed with magnesium titanate powder was used.
In the same manner as in Nos. To 5, R6 type anhydrous silver manganese dry batteries were produced.

With respect to each of the R6 type batteries manufactured as described above, light load discharge characteristics and pulse discharge characteristics during light load discharge were examined. The results are shown in Tables 1 and 2.
The light load discharge characteristics are as follows. For each of the 20 batteries, a continuous discharge of 1.2 kΩ load resistance is performed in an atmosphere of a temperature of 20 ° C., a duration up to a final voltage of 0.9 V, and a terminal voltage of 1.5 V, 1.3 V, The internal resistance of the battery was measured at 1.1 V and 0.9 V. Table 1 shows the average values.

The pulse discharge characteristics during light load discharge are as follows:
A continuous discharge of 1.2 kΩ load resistance was performed for each of the 20 batteries in an atmosphere at a temperature of 20 ° C.
A pulse discharge of 5 Ω for 60 seconds is superimposed once a day, and a duration up to a final voltage of 0.9 V and a terminal voltage of 1.5 V,
The internal resistance of the battery at 1.3 V, 1.1 V and 0.9 V was measured. The average values are shown in Table 2.

[0016]

[Table 1]

[0017]

[Table 2]

As is clear from Tables 1 and 2, the batteries of the examples of the present invention show almost no increase in internal resistance from the middle stage of discharge (1.3 V). This means that the terminal voltage drop is small. Further, it can be seen that the increase in internal resistance from the middle stage of discharge (1.3 V) when a 5Ω pulse discharge is superimposed is extremely small as compared with the battery of the comparative example.

Among the above embodiments, the effects of the present invention are smaller in the fourth and fifth embodiments than in the other embodiments.
Therefore, it is understood that the addition amount of magnesium titanate is preferably 0.2 to 0.6 parts by weight based on 100 parts by weight of the manganese dioxide powder.

Further, in the above embodiment, an example of light load discharge of 1.2 kΩ discharge for an R6 type battery was shown. However, the battery of the present invention is also applicable to heavy load discharge having a lower load resistance. It was found that the battery exhibited better discharge performance than the battery.

[Examples 6 to 12] (Preparation of positive electrode mixture) In the same manner as in Examples 1 to 5, electrolytic manganese dioxide or chemically synthesized manganese dioxide 100 was prepared.
0.0 parts by weight of magnesium titanate based on parts by weight,
A positive electrode mixture containing 0.2 parts by weight and 0.3 parts by weight was prepared.

(Preparation of Separator) A separator consisting of 100 parts by weight of a paste (composed of corn starch starch and polyvinyl alcohol; weight ratio of 10: 1) and 116 parts by weight of water was mixed with 0.0 part by weight of magnesium titanate powder. 0.1 part by weight, 0.2 part by weight, 0.3 part by weight, 0.1 part by weight.
4 parts by weight, 0.6 parts by weight, and 0.7 parts by weight were added and mixed and stirred. The mixture was applied to one surface of kraft paper so as to have an adhesive of 22 g / m ² and dried. .

(Production of Battery) Using the R6 type anhydrous silver manganese dry battery shown in FIG. 1 and the above-mentioned positive electrode mixture and separator, batteries of Examples 6 to 12 and Comparative Example 3 shown in Table 3 were produced. .

In place of the above magnesium titanate powder, magnesium aluminate (MgAl ₂ O ₄ ) which can be expected to have the same effect as magnesium titanate is used.
The R6 type anhydrous silver manganese dry battery of Comparative Example 4 shown in Table 3 was produced by incorporating the composition in a separator.

(Evaluation of Battery) R6 manufactured as described above
With respect to the battery, light load discharge characteristics and pulse discharge characteristics during light load discharge were examined, and the results are shown in Tables 4 and 5. The light load discharge characteristics are as follows. For each of the 20 batteries, a continuous discharge of a 1.2 kΩ load resistance is performed in an atmosphere at a temperature of 20 ° C., a duration up to a voltage of 0.9 V throughout and a terminal voltage of 1.5 V, 1.3 V, The internal resistance of the battery was measured at 1.1 V and 0.9 V. The average value is shown in Table 4. The pulse discharge characteristics at the time of light load discharge were as follows.
Perform a continuous discharge of 2kΩ load resistance,
A pulse discharge of 5Ω for 60 seconds is superimposed, and a duration up to a final voltage of 0.9 V and a terminal voltage of 1.5 V, 1.3 V are applied.
V, 1.1 V and 0.9 V were measured for battery internal resistance. The average value is shown in Table 5.

[0026]

[Table 3]

[0027]

[Table 4]

[0028]

[Table 5]

As is clear from Tables 4 and 5, in the batteries of the examples of the present invention, the internal resistance hardly increased from the middle stage of discharge (1.3 V), which means that the terminal voltage decreased little. I do. Further, when a 5Ω pulse discharge is superimposed, the rise of the internal resistance from the middle stage of the discharge (1.3V) is as follows.
It turns out that it is extremely small compared with the comparative battery. As described above, by including a titanate in at least one of the positive electrode mixture and the paste layer of the separator as in the present invention, it is possible to obtain extremely excellent discharge performance as compared with a conventional battery.

Although an example of light load discharge of 1.2 kΩ discharge for an R6 type battery has been described above, the battery of the present invention is also superior to a conventional battery for heavy load discharge with a lower load resistance. It showed that it showed discharge performance.

In the above embodiment, magnesium titanate (MgTiO ₃ ) was used as the titanate.
Calcium titanate (CaTiO ₃ ), barium titanate (BaTiO ₃ ), strontium titanate (SrT
iO ₃ ) is also effective.

[0032]

As described above, the present invention provides a light-load discharge characteristic and a light-load discharge property by using at least one of a positive electrode mixture of a manganese dry battery and a paste of a separator to which titanate is added. The pulse discharge characteristics at the time of discharge could be improved, and a manganese dry battery having excellent discharge characteristics could be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view of an R6-type manganese dry battery according to an embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Positive electrode mixture, 2 ... Carbon rod, 3 ... Zinc can, 4 ... Separator, 5 ... Sealing plate, 6 ... Sealing agent, 7 ... Metal outer cylinder.

Claims (5)

[Claims] In a manganese dry battery using a positive electrode mixture using manganese dioxide as a positive electrode active material, a zinc negative electrode, and a kraft paper separator coated with a paste layer, at least one of the positive electrode mixture and the paste layer is provided. A manganese dry battery characterized in that it contains titanate. 2. The manganese dry battery according to claim 1, wherein the titanate is an alkaline earth metal salt powder. 3. The manganese dry battery according to claim 1, wherein the manganese dioxide is electrolytic manganese dioxide neutralized with an alkaline aqueous solution or chemically synthesized manganese dioxide. 4. The manganese according to claim 1, wherein the amount of titanate contained in the positive electrode mixture is 0.2 to 0.6 parts by weight based on 100 parts by weight of the manganese dioxide powder in the positive electrode mixture. Dry batteries. 5. The manganese dry battery according to claim 1, wherein the amount of titanate contained in the paste layer is 0.2 to 0.6 parts by weight based on 100 parts by weight of the paste.