JP2005353427A - Manufacturing method of paste form active material for positive electrode - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a paste form active material for a positive electrode, capable of reducing a charge amount in chemical conversion and capable of manufacturing a long-lifetime lead-acid battery. <P>SOLUTION: Slurry, formed by agitating red lead and diluted sulfuric acid and by cooling it to 70°C or below, is manufactured in advance. Water is added to lead powder and cut fibers to knead them, and a kneaded substance is thereby manufactured. Then, the manufactured slurry is added to the kneaded substance made, by adding water to the lead powder and the cut fibers and by kneading them, and they are kneaded at a temperature below 70°C in a reduced-pressure state, to manufacture this pasty active material for a positive electrode. In this way, the pasty active material for a positive electrode manufactured like that is put in a collector made of a lead-calcium-tin alloy manufactured by a casting method to manufacture a paste-type positive electrode plate by aging and drying it. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing a paste-like active material for a positive electrode used for producing a lead storage battery.

  Lead-acid batteries are widely used in automobiles, uninterruptible power supplies, and the like because they have the feature of being inexpensive and highly reliable. In recent years, there is an increasing demand for cost reduction and longer life of lead-acid batteries used in these.

  For these lead-acid batteries, a paste-type positive electrode plate produced by applying a paste-like active material to a lead-calcium-tin alloy current collector or a lead-antimony-tin alloy current collector is generally used. Has been used. In order to reduce the cost of the paste-type positive electrode plate, a method of reducing the charge amount at the time of chemical conversion by adding red lead to the paste-like active material is effective.

  Conventionally, as shown in FIG. 2, lead powder and synthetic resin fiber (for example, cut fiber) are added to lead powder mainly composed of lead monoxide and mixed, and then dilute sulfuric acid is added to atmospheric pressure. The paste-like active material for positive electrode was manufactured by kneading (see, for example, Patent Document 1).

JP 2004-55417 A

  However, the use of a paste-type positive electrode plate produced by adding lead to the paste active material for the positive electrode has a problem in that the life of the lead storage battery is shortened although the amount of charge during chemical conversion can be reduced. It was. When this manufacturing method is used for a liquid lead-acid battery such as an automobile battery, there is a problem that its life is likely to be further shortened.

  The objective of this invention is providing the manufacturing method of the paste-form active material for positive electrodes which can manufacture a long-life lead storage battery while adding the amount of lead and reducing the charge amount at the time of chemical conversion.

  In order to solve the above problems, in the present invention, a slurry is prepared by adding red lead to dilute sulfuric acid and stirring it. Then, a slurry prepared in advance is added to a mixture of lead powder and a synthetic resin fiber (for example, cut fiber) and water is kneaded. To manufacture.

  That is, the invention of claim 1 is a method for producing a positive electrode paste-like active material for filling a lead alloy current collector to produce a paste-type positive electrode plate, wherein the positive electrode paste-like active material is used. The substance contains lead powder, synthetic resin fiber, red lead, dilute sulfuric acid and water, and the positive paste active material is added to the dilute sulfuric acid and stirred to prepare a slurry. In addition, the water is added to the mixture of the lead powder and the synthetic resin fiber to knead to prepare a kneaded product, and the slurry is added to the kneaded product and kneaded in a reduced pressure state to produce. It is characterized by being.

  The invention of claim 2 is characterized in that, in the invention of claim 1, the slurry is kneaded in addition to the kneaded material after being cooled to 70 ° C. or less.

  The invention of claim 3 is the invention of claim 1 or claim 2, wherein the kneaded product and the slurry are kneaded in a reduced pressure state at a pressure of 50 to 100 hPa as the pressure in the kneading container at the time of kneading. It is characterized by that.

  As an effect of the present invention, it is possible to provide a method for producing a paste-like active material for a positive electrode that can reduce the amount of charge at the time of chemical conversion and can produce a long-life lead-acid battery.

1. Production of Paste Active Material for Positive Electrode and Paste Type Positive Electrode Plate In the following, an example of production of a paste active material for positive electrode and a paste type positive electrode plate and a conventional comparative example will be described in detail with reference to FIGS. do.

(Example)
As an example according to the present invention, a paste-like active material for positive electrode was produced by the method shown in FIG. That is, as shown in FIG. 1, dilute sulfuric acid with a specific gravity of 1.260 is added to 132 liters, 159 kg of red lead is added with stirring, and then cooled to 70 ° C. or lower. Make it. Here, in this embodiment, as shown in FIG. 1, two agitators were used, and the slurry was cooled for about 40 minutes while being cooled with water, so that a slurry of 70 ° C. or less was obtained. That is, the stirrer is also provided with a cooling device. It should be noted that when stirring with dilute sulfuric acid, compared with the case where dilute sulfuric acid is added with dilute sulfuric acid, stirring can be carried out without difficulty. Can be improved.

  In the present invention, a kneading apparatus capable of reducing the pressure in the container during kneading is used. In other words, in a kneading machine that can be depressurized, 900 kg of lead powder mainly composed of lead monoxide and 1.6 kg of synthetic resin fiber-cut fiber are mixed under normal pressure, and 113 liters of water is added. Kneaded to prepare a kneaded product. Here, since the kneading is performed only with water and not the kneading with dilute sulfuric acid as conventionally used, it is possible to easily prevent corrosion of piping equipment used and the handling thereof.

  And the said slurry cooled to 70 degrees C or less is added to the kneaded material with lead powder, a cut fiber, and water, and the pressure in a kneading container is 50- at the temperature of 70 degrees C or less, ie, the temperature of 40-70 degreeC. A paste-form active material for a positive electrode was prepared by kneading in a reduced pressure state of 400 hPa.

  Thereafter, the prepared paste-like active material for positive electrode is filled into a lead-calcium-tin alloy current collector manufactured by a casting method by a conventional method, and aged and dried to manufacture a paste-type positive electrode plate. .

(Comparative example)
As a comparative example, a pasty active material for positive electrode was prepared by the conventional method shown in FIG. That is, as shown in FIG. 2, 900 kg of lead powder containing lead monoxide as a main component, 1.6 kg of cut fiber, and 159 kg of red lead are mixed in a kneader to produce a mixture.

  Then, dilute sulfuric acid with a specific gravity of 1.260 added to 132 liters and 113 liters of water was added to the mixture and kneaded at atmospheric pressure to prepare a paste-like active material for a positive electrode.

Thereafter, the prepared paste-like active material for positive electrode is filled into a current collector made of lead-calcium-tin alloy manufactured by a casting method by a conventional method, and aged and dried to manufacture a paste-type positive electrode plate.
2. Manufacture and life test of control valve type lead acid battery Two types of paste type positive electrode plates produced by the above-mentioned method and three types of paste type negative electrode plates that have been used in the past are made of glass fiber retainers. The electrode plates are assembled by welding and assembled into an ABS battery case, and a dilute sulfuric acid electrolyte having a specific gravity of 1.21 (20 ° C.) is injected. Thereafter, the battery was formed under the conditions of a charge amount of 250%, a formation time of 88 hours, and an ambient temperature of 60 ° C., to produce a 30 Ah-2V control valve type lead storage battery.

  The produced control valve type lead-acid battery is discharged at 60 A (25 ° C., discharge end voltage: 1.6 V), and the initial discharge capacity is measured to confirm that there is no abnormality. And this control valve type lead acid battery is charged at a constant voltage in a constant temperature and humidity chamber of 60 ° C. and 30% humidity (2.275 V / cell, limited current 3 A), taken out every 32 days, cooled, and initially The discharge capacity test was conducted under the same conditions as in FIG. And the time when the discharge capacity fell below 70% of the initial value was judged as the life.

  Table 1 shows the results of a life test on the control valve type lead storage batteries of the above-described Examples and Comparative Examples. From Table 1, it can be seen that the valve-regulated lead-acid battery according to the present invention has a long life. Although the detailed reason is unknown, if the method for producing a positive electrode paste-like active material according to the present invention is used, the dispersibility of the red lead is improved and sufficient defoaming can be performed during kneading in a reduced pressure state. For this reason, the adhesion to the current collector is improved, and good tetrabasic lead sulfate is obtained in the aging / drying process, and it is considered that charging is easily performed in the subsequent chemical conversion process. .

  Although the detailed reason is unknown, the slurry produced by stirring dilute sulfuric acid and red lead is 70 ° C. or lower as described above, more preferably lead powder, after cooling to 60 ° C. or lower. When added to a mixture of cut fiber and water, it was found that the control valve type lead-acid battery is stable and more preferable.

  Therefore, as shown in FIG. 1, since a sufficient amount of cooling time is required for the production of the slurry produced by stirring dilute sulfuric acid and red lead, the slurry is produced alternately by using two or more slurry production apparatuses. (In FIG. 1, it was clearly indicated as slurry 1 and slurry 2). And workability | operativity can be improved if the stirring apparatus is cooled beforehand by means, such as water cooling, and it pumps out alternately using a pump suitably and uses it.

  Especially in summer when the ambient temperature is high, slurry is manufactured in advance by a plurality of slurry manufacturing processes, cooled to 70 ° C. or lower, more preferably 60 ° C. or lower, and alternately using pumps or the like as appropriate. The method of supplying is effective. In addition, since the slurry of dilute sulfuric acid and red lead according to the present invention has a low viscosity, it can be easily transported over a long distance using a normal pump.

  In addition, as the pressure in the kneading container at the time of kneading the positive electrode paste-like active material kneaded in a reduced pressure state, in addition to being more preferable in terms of the life of the control valve type lead-acid battery, It was found that there was no problem in workability. The reason for this is considered to be that the positive electrode paste-like active material can be sufficiently degassed during kneading in a reduced pressure state.

  The positive electrode paste-like active material according to the production method according to the present invention is not limited to the production of the control valve type lead acid battery as described above, and can be used in the same manner for the production of the liquid type lead acid battery. .

It is the schematic of the manufacturing process of the paste-form active material for positive electrodes concerning this invention. It is the schematic of the manufacturing process of the conventional paste-form active material for positive electrodes.

Claims (3)

A method for producing a positive electrode paste active material for filling a lead alloy current collector to produce a paste type positive electrode plate,
The positive electrode paste-like active material contains lead powder, synthetic resin fiber, red lead, dilute sulfuric acid and water,
The positive electrode paste-like active material is prepared by adding the red lead to the dilute sulfuric acid and stirring to prepare a slurry, and adding the water to the mixture of the lead powder and the synthetic resin fiber and kneading. A method for producing a paste-like active material for a positive electrode, wherein the product is prepared by adding the slurry to the kneaded product and kneading the mixture in a reduced pressure state. 2. The method for producing a paste-like active material for a positive electrode according to claim 1, wherein the slurry is cooled to 70 ° C. or less and then kneaded in addition to the kneaded product. The paste-like active for a positive electrode according to claim 1 or 2, wherein the kneaded product and the slurry are kneaded in a reduced pressure state at a pressure of 50 to 100 hPa as the pressure in the kneading container when kneaded. A method for producing a substance.

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