JPH08138657A - Manufacturing method of electrode plate for lead-acid battery - Google Patents

Abstract

(57) [Abstract] [Purpose] A thin active material layer can be formed on the surface of a thin support, and 3PbO / PbSO ₄ and P can be formed.
It is intended to provide an electrode plate for a lead storage battery which is excellent in reactivity and bondability due to generation of bO.H ₂ O and the like. [Structure] A step of preparing a slurry containing lead powder and water as main components without adding sulfuric acid, a step of applying the slurry to a support, and a step of bringing the support applied with the slurry into contact with dilute sulfuric acid. And a step of aging the support coated with the slurry in air after being brought into contact with dilute sulfuric acid.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead acid battery, and more particularly to its electrode plate, and more particularly to a method of manufacturing an electrode plate capable of thinly coating an active material on a support.

[0002]

2. Description of the Related Art In recent years, lead acid batteries have been under development for a high output battery, and the electrode plates are made thinner to increase the number of electrode plates to be housed in the battery, or the holes provided in the current collector are reduced. You can improve the current collection efficiency by reducing the diameter and fine pore distribution.
In addition, studies have been conducted to make the long electrode plates spiral to increase the contact area between the electrode plates. In order to realize such a battery, it is necessary to form a thin active material layer of 500 to 100 μm or less on the electrode plate.

Conventionally, an electrode plate for a lead storage battery is prepared by mixing lead oxide, lead powder containing lead as a main component and an active material, dilute sulfuric acid, water, etc., and kneading them to obtain an active material paste. A support such as a cast grid body or an expanded grid body having a thickness of 1.5 to 2 mm was filled with the paste, which was then aged and dried in an atmosphere of an appropriate temperature and humidity to obtain an electrode plate.

In this process, lead oxide (Pb
O) and dilute sulfuric acid (H ₂ SO ₄ ) react to produce tribasic lead sulfate (3PbO · PbSO ₄ ) and form chemical compound based on this to obtain highly reactive lead dioxide (PbO ₂ ).
Lead (Pb) reacts with oxygen and moisture during aging to produce Pb
Generate O · H ₂ O to increase the binding force between active materials, had gained appropriate porosity electrode plate by further growth of these crystals.

[0005]

However, when an active material paste prepared by a conventional method is applied to the surface of a thin support to obtain a thin electrode plate, the addition of sulfuric acid causes the formation of lead sulfate. The generation of the active material paste particles causes agglomeration, and since a large number of coarse coagulated masses are present, the paste cannot be thinly applied to the surface of the support, which causes a problem that the application work is difficult.

The present invention is intended to solve such a problem, and it is possible to form a thin active material layer on the surface of a thin support and to obtain 3PbO.PbSO ₄ and PbO.
-Provides an electrode plate for a lead storage battery, which is excellent in reactivity and bondability due to generation of H ₂ O and the like.

[0007]

In order to solve the above-mentioned problems, a method of manufacturing an electrode plate for a lead storage battery according to the present invention is a slurry of a lead compound containing lead powder and water as main components without adding sulfuric acid. And a step of applying the slurry to a support, a step of immersing the support applied with the slurry in dilute sulfuric acid, and taking out the support applied with the slurry from dilute sulfuric acid. And aging in air.

[0008]

In the present invention, since lead powder, which is an active material, and water are mixed as main components without adding sulfuric acid, solidified lumps are not generated due to the production of lead sulfate, and the mixed state of these is the active material particles. Is suspended in water and becomes a slurry state. Therefore, when the slurry of the active material is applied to the support made of a thin porous body having pores, it is easy to form a thin layer of the active material on the support, and the porosity can be appropriately maintained. it can.

Then, after applying the slurry to the support,
Since this support is immersed in dilute sulfuric acid, the lead oxide in the lead powder changes to lead sulfate, the active material layer begins to harden, and the binding force between the active materials increases.

Thereafter, the support is heated to, for example, a temperature of 40.degree.
Since it is aged in air at 80 ° C and humidity of 80% to 100%, tribasic lead sulfate can be produced by the reaction of lead oxide and dilute sulfuric acid, and the reactivity of lead dioxide during battery charge and discharge. Can be increased.

At this time, the bond strength between the active materials can be further increased by the oxidation of the unoxidized lead. Therefore, in the present invention, the lead powder, which is the active material, can be thinly applied to the support in a slurry state, and thereafter the support is immersed in dilute sulfuric acid and further aged in the air. It is possible to obtain highly reactive lead dioxide by increasing the bond strength between substances and forming tribasic lead sulfate.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a method of manufacturing the lead-acid battery electrode plate of the present invention. In FIG. 1, 1 is lead powder, 2 is an additive such as acid-resistant conductive material, sizing agent, resin cut fiber, etc., 3 is water, 4 is a process of mixing these to prepare a slurry, and 5 is a support. Step of applying the slurry, 6 is a drying step, 7 is a step of immersing the support on which the slurry is applied in dilute sulfuric acid, and 8 is a step of aging the support taken out from the dilute sulfuric acid in the air. Is.

Here, as the lead powder, a lead powder having an oxidation degree of 50% to 90% was used. Also, the water content is 10% to the weight of the lead powder.
It was added at a rate of 100%. And 40 for lead powder
The positive electrode plate obtained by the above process is added to the positive electrode plate A, which is effective for promoting chemical conversion of the positive electrode plate (Pb).
₃ O ₄ ) was mixed with 20% by weight of lead powder, and 40% by weight of water was added, and the positive electrode plate obtained by the above process was used as the positive electrode plate B. The positive electrode plate added with 5% by weight was designated as positive electrode plate C.

As a support, 0.3 mm × 0.3
An expanded porous body made of lead alloy and having a rhombic hole portion of 0.2 mm and a thickness of 0.2 mm was used, and the slurry was applied at a thickness of 100 mg / cm ² and a thickness of 180 μm as shown in FIG. 3 (A).

As described above, according to the manufacturing method of the present invention, a thin electrode plate can be manufactured. Then, the support coated with the slurry was immersed in dilute sulfuric acid having a specific gravity of 1.4 for 30 seconds. Then, the support taken out from the diluted sulfuric acid was heated to a temperature of 40
It was aged for several hours to several tens of hours in an atmosphere of 80 ° C to 80 ° C and humidity of 80% to 100%.

On the other hand, the negative electrode plate was prepared by using a slurry in which 5% by weight of carbon powder, 2 to 4% by weight of lignin sulfonate and 40% by weight of water were added to lead powder.

Then, each of the positive electrode plates A, B and C was combined with the negative electrode plate to prepare a lead storage battery of 2V25 mAh, and these were prepared into batteries A, B and C of the present invention.

Then, the change in discharge voltage when these batteries were formed in diluted sulfuric acid having a specific gravity of 1.20 and discharged at a current density of 25 mA / cm ² was examined. The result is shown in FIG.

As shown in FIG. 4, the battery A showed good discharge characteristics, but the battery B using the positive electrode plate containing lead tin, which has good chargeability during formation, and the carbon powder as the conductive particles. The discharge voltage and the discharge time of the battery C using the positive electrode plate added with were higher than those of the battery A.

On the other hand, as shown in FIG. 2, a step 10 of mixing lead powder 1, an additive 2, water 3, and dilute sulfuric acid 9 to knead the paste, and applying the paste to a support. Process 1
An attempt was made to obtain a polar plate by applying a paste to a support made of a lead alloy expanded porous body having a thickness of 0.2 mm by a conventional manufacturing method consisting of 1, a drying step 6, and an aging step 8. However, due to the formation of lead sulfate, a large number of coarse aggregates of paste particles were generated, and the paste could not be successfully applied onto the support.

Then, a battery D was prepared by using a positive electrode plate in which 5% by weight of silica powder and 1% by weight of a starch sizing agent were further added to the positive electrode plate B, and the batteries A, B and D were used for charge / discharge cycles. A life test was conducted.

This test was carried out at a current density of 25 mA / cm ² by charging 125% of the previous discharge amount and discharging 20% of the complete discharge amount.

The results are shown in FIG. As shown in FIG. 5, although the battery A showed good cycle characteristics, the battery B,
In D, the capacity after the lapse of cycles was higher.

Next, the relationship between the specific gravity of dilute sulfuric acid in the dipping process of the support coated with the slurry in dilute sulfuric acid and the dipping time of the electrode plate was investigated.

The results are shown in FIG. Where T1, T
Nos. 2, T3, T4, and T5 have immersion times in dilute sulfuric acid of 30 seconds, 1 minute, 5 minutes, 10 minutes, and 60 minutes, respectively.

As can be seen from FIG. 6, as the specific gravity of dilute sulfuric acid increased, the active material utilization rate of the electrode plate improved even when the dipping time in dilute sulfuric acid was shortened.

In this embodiment, the support coated with the slurry was immersed in dilute sulfuric acid, but a dilute sulfuric acid treatment may be performed by applying a shower or spray of dilute sulfuric acid to this support.

Further, the additive added to the lead powder may be calcium oxide particles for maintaining good porosity of the electrode plate, lignin and its derivative, barium sulfate, etc. added to the negative electrode, in addition to the present embodiment. good.

Further, although the expanded porous body is used as the support in this embodiment, other supports such as punching metal having a thin plate provided with openings as shown in FIG. 3B may be used. good.

[0031]

INDUSTRIAL APPLICABILITY As described above, in the present invention, a slurry is prepared by using lead powder which is an active material and water as main components, and this slurry is applied to a support. A thin layer can be formed, and high output of the battery can be achieved.

Further, the support coated with the slurry is dipped in dilute sulfuric acid, and then the support is aged in air to form tribasic lead sulfate for obtaining highly reactive lead dioxide. It is possible to promote the production of lead oxide which enhances the bonding force between the active materials.

[Brief description of drawings]

FIG. 1 is a diagram showing a manufacturing process of an electrode plate for a lead storage battery of the present invention.

FIG. 2 is a diagram showing a manufacturing process of a conventional electrode plate for a lead storage battery.

FIG. 3A is a side view of the electrode plate of the present invention using an expanded porous body. FIG. 3B is a side view of the electrode plate of the present invention using a punching metal.

FIG. 4 is a diagram showing discharge characteristics of the lead acid battery of the present invention.

FIG. 5 is a diagram showing charge / discharge cycle characteristics of the lead acid battery of the present invention.

FIG. 6 is a graph showing the relationship between the immersion time of the electrode plate of the present invention in diluted sulfuric acid and the specific gravity of diluted sulfuric acid.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lead powder 2 Additive 3 Water 4 Slurry adjusting step 5 Slurry applying step 6 Drying step 7 Immersion step 8 Aging step 9 Dilute sulfuric acid 10 Paste kneading step 11 Paste applying step

Claims (4)

[Claims] 1. A step of preparing a slurry of a lead compound containing lead powder and water as main components without adding sulfuric acid, a step of applying the slurry to a support, and a step of applying the slurry to the support. A process for producing an electrode plate for a lead storage battery, which comprises a step of contacting with dilute sulfuric acid and a step of aging the support coated with the slurry in air after contacting with dilute sulfuric acid. 2. The method for producing an electrode plate for a lead storage battery according to claim 1, wherein the slurry contains red lead. 3. The method for producing an electrode plate for a lead storage battery according to claim 1, wherein the slurry contains acid resistant conductive particles. 4. The method for producing a lead-acid battery electrode plate according to claim 1, wherein the concentration of the dilute sulfuric acid is 1.20 or more.