KR800001519B1 - Polar plate of alkaline storage cell - Google Patents

Abstract

A composition of anode compound contains mainly MnO2 and AgO, HgO or these mixt. at the rate of 1 or 50 wt. % of an Mn O2. Fig.l is a cross section of small cell using anode compound of this invention. Externals of cell(11) and (12) are made up of cold strip. Anode compound(13) which is thickness of 1.1 mm forms on anode externals (12) under pressure. Zinc-cathode(14) which is a diameter of 7.15 mm, thickness of 1,0mm and weight of 200 mg, is established. An electrolyte absorbent (15) obtained from polypropylene is a diameter of 7.5 mm and a separator (16) obtained from cellophane is a diameter of 10.8 mm.

Description

Cathode Mixture Composition of Alkaline Manganese Battery

1 is a cross-sectional view of a battery produced using the cathode mixture of the present invention.

2 is a discharge curve of a battery produced using the positive electrode mixture of the present invention.

3 is a change in discharge time of the battery according to the positive electrode mixture composition.

The present invention relates to a positive electrode mixture composition of an alkaline manganese battery. In more detail, the present invention relates to a composition of a high-performance alkaline manganese active material for high-performance alkaline manganese batteries, in which an anode adsorbent of an alkali manganese battery composed of manganese dioxide and a carbon mixture is added and mixed with silver oxide (II) or mercury oxide (II). .

Conventionally, as a positive electrode mixture of an alkaline manganese battery, a mixture of electrolytic manganese dioxide or a manganese dioxide produced by a chemical method, a conductor such as graphite, and a binder such as carboxy methyl cellulose is used. However, alkaline manganese batteries using manganese dioxide as a bimodal active material have a large voltage drop during discharging, and when used as small batteries, their utility is low. It has a flaw. These shortcomings are a major limitation in using alkaline manganese batteries as power sources for cameras, wristwatches, electronic calculators and hearing aids.

In order to solve the shortcomings of the conventional alkaline manganese batteries, the increase in the resistance of the positive electrode mixture during discharge is alleviated, thereby reducing the voltage drop caused by the discharge, and at the same time, reducing the amount of carbon added to the inert material or the electrical conductor, thereby reducing the active material of the battery. There is a method of increasing the amount of and increasing the public battery capacity by adding a high energy active material. In addition, the utility of manganese dioxide can be increased by the secondary reaction between the additives described above and manganese dioxide during discharge. It is well known to add a small amount of low manganese oxides, i.e., Mn ₂ O ₃ or Mn ₃ O _4, to the cathode mixture of an expensive silver oxide battery or a mercury oxide battery to improve the performance of the battery and to improve it for use. U.S. Patent No. 3,600,231 and Japanese Patent Laid-Open No. 51-121,736. However, there is no known positive electrode mixture for alkaline manganese batteries, which has a performance comparable to that of expensive silver oxide or mercury oxide batteries by adding a small amount of active material of alkaline batteries as an active material of an inexpensive alkaline manganese battery cathode mixture.

In the present invention, by using manganese dioxide as a main component of the positive electrode mixture, adding silver oxide (II), mercury oxide (II), or a mixture thereof within 50% of the weight of manganese dioxide to alleviate voltage increase during discharge, and improve the utility of manganese dioxide as an active material. It is intended to provide a positive electrode mixture composition of an alkaline manganese cell which has excellent battery performance and a large battery capacity by increasing its proximity to%.

When described in detail through the drawings showing the performance of the battery and the previous cell using the positive electrode mixture of the present invention as an active material.

1 is a cross-sectional view of a small battery fabricated using the positive electrode mixture of the present invention, (11) and (12) is a battery appearance molded from a cold-rolled steel sheet, the positive electrode mixture (13) to the positive electrode appearance (12) Was pressurized to 1.1 mm, and a zinc anode 14 having a diameter of 7.15 mm, a thickness of 1.0 mm and a weight of 200 mg was installed, and a polypropylene electrolyte absorbent 15 having a diameter of 7.5 mm, and a cellophane with a diameter of 10.8 mm. Installed separator 16.

Battery shells 11 and 12 were sealed under pressure with an insulator 17 therebetween. 0.13 ml of 40% potassium hydroxide aqueous solution was used as the electrolyte of this battery and injected into the absorber 15 before sealing it under pressure, and this electrolyte was consequently filled in the angular space of FIG. The final cell is 11.5 mm in diameter and 4.2 mm in height.

2 is a discharge curve showing the voltage change with the discharge time of the battery using the positive electrode mixture and the control positive electrode mixture of the present invention. Here, the discharge is a continuous discharge at room temperature by the load resistance of 4700Ω, the discharge curve (A) is a 90% by weight electrolytic manganese dioxide and 10% by weight graphite mixture, which is a common positive electrode mixture composition of the conventional alkaline manganese battery A positive electrode mixture was used for (b) 80 wt% electrolytic manganese dioxide, 10 wt% graphite and 10 wt% mercury oxide (II), and (c) 54 wt% electrolytic manganese dioxide, 10 wt% graphite and 36% by weight of mercury (II) oxide, (D) used 80% by weight manganese dioxide, 10% by weight graphite and 10% by weight silver oxide (II) as the positive electrode mixture.

The thickness of these positive electrode mixtures was 1.1 mm as described above, and the amount required was as shown in the examples.

It can be seen from FIG. 2 that the battery using the positive electrode mixture according to the present invention has significantly improved the voltage drop and discharge duration during discharge compared with the conventional battery using the positive electrode mixture.

3 shows the ratio of the discharge time between the battery using the positive electrode mixture of the present invention and the conventional alkaline manganese battery according to the content of mercury oxide (II) in the positive electrode mixture, wherein 90% by weight manganese dioxide and 10% by weight graphite mixture are shown. When the discharge time of the used battery was 1, the discharge time according to the content of mercury oxide (II) was shown. At this time, the amount of graphite was fixed at 10% by weight. The curve (a) is the result of the discharge time up to 1.2 volts when discharged at room temperature for 8 hours at 2200Ω load resistance daily.The curve (b) is the ratio of the discharge time to 0.90 volts after continuous discharge at 4700Ω. .

The positive electrode mixture of the present invention improves the electrode forming conditions and low battery capacity of the conventional alkaline manganese battery in addition to the above-described improvement of the discharge characteristics. Alkaline manganese batteries generally have a low electrical conductivity between the used manganese dioxide, so that about 10% by weight of a conductor, for example, graphite or acetylene black, is mixed to make a positive electrode mixture, and silver oxide (II) and mercury oxide (II) are electrochemically Since the phosphorus reaction product is silver or mercury, which is in a state of extremely high electrical conductivity, a battery containing them as a main component can reduce the amount of conductors such as carbon by 2 to 3%. It is about 50% larger than manganese batteries. In addition, high battery capacity of a mercury oxide battery or a silver oxide battery is related to the high density of silver oxide (II) or mercury oxide (II).

Therefore, the capacity of the battery is increased by adding silver oxide (II) or mercury oxide (II), which have a high density and high electrical conductivity of the electrochemical product, to the positive electrode mixture of the alkaline manganese battery, and further, the capacity of the battery is reduced by lowering the amount of carbon. You can increase it.

When mercury (II) is used, the pressure during electrode formation can be about 1/2 of that of manganese dioxide. The pressure for forming the electrode can be lowered by adding silver (II) oxide or mercury (II) oxide to manganese dioxide.

The increase in the electrochemical efficiency of the positive electrode mixture according to the present invention can be explained that the silver or mercury in the metallic state generated during the discharge process is due to the increase in the electrical conductivity of the positive electrode mixture.

As shown in Table 1, it can be seen that a battery using a mixture of manganese dioxide and graphite to which 40% potassium hydroxide aqueous solution was added has superior discharge characteristics than the case where no potassium hydroxide aqueous solution is added to the positive electrode mixture. It is believed that the increase in the electrical conductivity during discharge is a factor to alleviate the severe voltage drop caused by the discharge of conventional alkaline manganese batteries. However, the increase in electrical conductivity is not seen as the sole reason for increasing the electrochemical effectiveness of the positive electrode mixture according to the present invention, and the complex interaction between manganese dioxide and silver oxide (II) or mercury oxide (II) or their electrochemical reaction products It is considered that it is also caused by the reaction.

Table 1 shows the same volume of battery within the experimental error range, namely 11.5mm diameter and 4.2mm high battery (Figure 1), using a typical cathode mixture according to the present invention, given by continuous discharge at a resistance of 4700Ω. The discharge time up to the voltage was shown.

TABLE 1

Relationship between Voltage and Discharge Time during Continuous Discharge at 4700Ω Resistance by Cathode Mixture Composition

The composition of the optimum positive electrode mixture according to the present invention differs depending on the price of silver oxide (II) or mercury oxide (II), the performance of the desired battery, the use of the battery, and the like.

If the desired cell needs to be discharged with a high current at a constant voltage, for example, a battery for a purpose such as a camera flash, the content of mercury oxide (II) or silver oxide (II) in the positive electrode mixture is increased and a low current discharge is required. In the case of a battery, its content can be lowered to a few%. As an additive, mercury sulfate (II) can be used instead of mercury oxide (II). Since mercury sulfate in the positive electrode mixture reacts with the electrolyte of the battery to produce mercury oxide (II), the addition of mercury sulfate (II) has the same effect as the addition of mercury oxide (II).

The positive electrode mixture of the present invention is a composition containing manganese dioxide as a main component, containing carbon, and containing silver (II) oxide or mercury oxide (II), and a small amount of organic compound such as polystyrene as a binder depending on the battery manufacturing process, the use of the battery, and the like. Or a composition to which potassium hydroxide solution is added. In addition, the positive electrode mixture of the present invention can be applied to a battery of any size other than the small button type shown in FIG.

The present invention will be described in detail with reference to the following examples, and specific discharge test results are as described above with reference to FIGS. 2, 3, and 1. Percentages herein refer to weight ratios unless otherwise noted.

Example 1

5 g of graphite was added to 45 g of international sample manganese dioxide # 2, mixed for 5 hours in a ball mill, and then 330 mg were taken. The anode was formed into pellets having a diameter of 10.83 mm at a pressure of about 4000 lbs. It is put in an external appearance and press-contacted at the pressure of about 5,000 pounds, and the battery shown in FIG. 1 is manufactured using each battery component and electrolyte solution mentioned above.

After 1 week at room temperature, these cells are discharged to 220 volts, 470 Ω, 1100 Ω, 2200 Ω and 4700 Ω to 0.9 volts, respectively.

The actual battery capacity calculated is from 31mAH (220Ω) to 50mAH (4700Ω).

Example 2

40% potassium hydroxide aqueous solution was added to 9% by the weight ratio of the total positive electrode mixture to the positive electrode mixture of Example 1 and mixed and weighed about 360mg each to prepare a battery and discharge test as in Example 1 The capacity of was 47 mAH to 66 mAH.

Example 3

A battery was prepared in the same manner as in Example 1 using 85% of manganese dioxide, 10% graphite, and 5% mercury (II) oxide as a positive electrode mixture, and 350 mg of the battery was prepared in the same manner as in Example 1, and the battery capacity was 36.3 mAH to 66.3 mAH It was.

Example 4

80% manganese dioxide, 10% graphite and 10% mercury oxide (II) were prepared as a positive electrode mixture, and 370 mg of the battery was produced and discharged in the same manner as in Example 1, and the battery capacity was 61 mAH to 88 mAH.

Example 5

In the same manner as in Examples 1, 3 and 4, 18% mercury oxide (II) was used. The capacity of the battery using 430 mg of positive mix was from 52.3 mAH to 108 mAH.

Example 6

36% mercury (II) oxide was used in the same manner as in Examples 1, 3, 4 and b. The capacity of the battery using 500 mg of positive mix was from 75 mAH to 128 mAH.

Example 7

The capacity of the battery using 350 mg of 80% manganese dioxide, 10% silver (II) oxide and 10% graphite as the cathode mixture was from 44 mAH to 84 mAH.

Example 8

The capacity of the battery using 850 mg of 97% mercury oxide (II) and 3% graphite as the positive electrode mixture was 117 mAH to 120 mAH.

Claims (1)

A positive electrode mixture composition of an alkaline manganese battery comprising manganese dioxide as a main component, and silver (II) oxide, mercury oxide (II), or a mixture thereof added in an amount of 1 to 50% by weight of manganese dioxide to form a cathode active material.

Images