JP2005044772A - Paste type positive electrode plate of lead-acid storage battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paste type positive electrode plate of a lead-acid storage battery not having red lead left independently in the paste. <P>SOLUTION: A paste material having a part 1 containing lead monoxide (PbO) as a main component and a part 2 containing red lead (Pb<SB>3</SB>O<SB>4</SB>) as a main component on the surface of a granular material 3 is used. The paste material can be obtained by baking the granular material containing lead monoxide as a main component. In this case, it is preferable that an average grain size is 10 μm or less, and that a degree of turning into red lead ranges between 50% and 95%. Thus, since lead monoxide and red lead are exposed on the grain surface structurally in a continuous state, reactivity with diluted sulfuric acid is heightened, combining force between the activator grains is strengthened, and fall-off of the activator is prevented. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a positive electrode plate for a paste-type lead-acid battery using a red lead.

  A conventional positive electrode plate for paste-type lead-acid batteries is made by kneading lead powder containing mainly lead and lead monoxide, dilute sulfuric acid, and water as main components, and filling this paste into the grid. It was manufactured with. The obtained paste type electrode plate was incorporated in a battery case, and dilute sulfuric acid was added to perform chemical charging.

In contrast to chemical charging by a conventional method, a technique for improving chemical conversion efficiency by mixing red lead in lead powder during kneading and kneading with dilute sulfuric acid is known (for example, see Patent Document 1). ).
Japanese Patent No. 2712520

  However, when a paste is made by mixing lead residue directly into lead powder, in practice, when lead monoxide and lead oxide are kneaded with water and dilute sulfuric acid, most of the dilute sulfuric acid reacts only with lead monoxide. To produce tribasic lead sulfate. Therefore, most of the red lead remains independently in the paste without reacting with sulfuric acid. The remaining red lead reacts with dilute sulfuric acid during chemical formation to produce lead sulfate and lead dioxide. Since the lead sulfate produced here is a very large crystal, it causes volume expansion during the formation, resulting in a decrease in the bonding force between the active material particles and a drop in the active material after the formation. There was a problem that led to

  An object of the present invention is to obtain a positive electrode plate for a paste-type lead storage battery that does not cause the red lead to remain in the paste independently.

The positive electrode plate for a paste-type lead-acid battery according to the present invention has a powder surface having a part mainly composed of lead monoxide (PbO) and a part mainly composed of lead (Pb ₃ O ₄ ). The paste raw material is used.

Moreover, the positive electrode plate for a paste type lead-acid battery according to the present invention is a fired product having a lead layer (Pb ₃ O ₄ ) layer on the surface layer by firing a powder mainly composed of lead monoxide (PbO). The paste raw material is a powder in which lead monoxide is exposed in a part of the surface layer.

  In this case, the average particle size of the fired product is preferably 10 μm or less.

  Moreover, it is preferable that the lead tanning degree is in the range of 50 to 95%.

  In the present invention, lead monoxide and lead oxide are exposed on the particle surface in a structurally connected state, so that the reactivity with dilute sulfuric acid is increased, the bonding force between the active material particles is enhanced, and the active material Dropout can be prevented.

  Hereinafter, the best mode for carrying out the present invention will be described based on examples in comparison with comparative examples.

First, lead dans having different lead tanning rates were prepared by changing the time with respect to lead powder mainly composed of lead monoxide. After that, the lead dans having a different rate of lead tanning is pulverized by a hammer mill method, and the portion 1 and lead tan (Pb ₃ O ₄ ) mainly composed of lead monoxide (PbO) are formed on the surface as shown in FIG. A powder 3 that is a paste raw material in which the main component 2 is present was prepared. In addition, although not shown in the figure, a part of the surface layer of the fired product having a lead layer (Pb ₃ O ₄ ) layer on the surface layer is scraped by firing a powder mainly composed of lead monoxide (PbO) to form a monoxide. A powder with exposed lead was prepared.

For the evaluation, the powders shown in Examples 1 to 6 and Comparative Examples 1 to 3 shown in Table 1 were used.

Next, each of these powders and 3 kg of lead powder with an oxidation degree of 75% are mixed, and then water and sulfuric acid having a specific gravity of 1.26 g / cm ³ are added and mixed, thereby preparing each positive electrode active material paste. did. The content of the red lead was 15% by mass with respect to the mixed powder. Each of these positive electrode active material pastes was filled into a grid used for a lead-acid battery D26 size for automobiles made of a lead-calcium alloy, and aged and dried to obtain a positive electrode plate.

Using these positive plates, a 2V single cell composed of seven positive plates / eight negative plates was prepared, and a sulfuric acid solution having a specific gravity of 1.24 g / cm ³ was poured into the 2 V single battery at a constant current of 22.5 A. The time was formed. First, FIG. 2 shows the chemical conversion efficiency (PbO ₂ conversion rate) when the degree of lead oxidation was changed. The chemical conversion efficiency was improved as the degree of lead oxidation was increased. However, when the content of red lead in the present invention was 15% by mass, no significant difference was found.

Table 2 shows the results of visual disassembly and removal of the active material from the lattice after partial disassembly after chemical conversion.

As shown in FIG. 1, the surface of the powder composed of red lead was treated so that a part 1 mainly composed of lead monoxide and a part 2 composed mainly of lead (Pb ₃ O ₄ ) were present. In some cases, no peeling or dropping off was observed with respect to the case where these treatments were not performed at all.

Next, using the 2V cell, 20A-1h discharge and 5A-5h charge are performed as one cycle at an ambient temperature of 40 ° C., and this is performed for 24 cycles, and then the battery voltage becomes 1.7V at 20A. The capacity was measured by charging the battery until it reached 50% of the initial capacity, and the test was performed with the lifetime as the point in time. The results are shown in Table 3.

  Regarding the life cycle, each of the single cells of Examples 1 to 6 exceeded that of Comparative Examples 1 to 3.

  Moreover, although it compared in Examples 1-6 of this invention, it became a tendency for cycling characteristics to fall conversely as the lead tanning degree was raised.

  In these cases, as shown in Table 1, the average particle size of the fired product is preferably 10 μm or less. Moreover, it is preferable that the lead tanning degree is in the range of 50 to 95%.

It is an expansion schematic of an example of the lead powder used by this invention. It is a comparison diagram of the chemical conversion efficiency when changing the red lead degree of Comparative Examples 1-3 and the Examples 1-6 of the present invention (PbO ₂ rate).

Explanation of symbols

1 Part mainly composed of lead monoxide (PbO) 2 Part mainly composed of lead (Pb ₃ O ₄ ) 3 Powder

Claims (4)

Paste type characterized by using a paste raw material in which a part mainly composed of lead monoxide (PbO) and a part mainly composed of lead (Pb ₃ O ₄ ) are present on the surface of the powder Positive electrode plate for lead acid battery. For a fired product having a lead layer (Pb ₃ O ₄ ) layer on the surface layer by firing a powder mainly composed of lead monoxide (PbO), a powder in which lead monoxide is exposed on a part of the surface layer is obtained. A positive electrode plate for a paste-type lead storage battery, characterized by using a paste raw material.   The positive electrode plate for a paste type lead-acid battery according to claim 2, wherein an average particle diameter of the fired product is 10 µm or less.   The positive electrode plate for a paste type lead-acid battery according to any one of claims 1 to 3, wherein the degree of lead tanning is in the range of 50 to 95%.

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