JP2000100424A - Lead-acid battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lead-acid battery preventing deterioration in charge acceptance and capacitance drop due to the insufficient charging, even at the time of increasing the amount of lignin for preventing early deterioration in a high rate charging and discharging even when repeating a charging and discharging cycle. SOLUTION: The amount of ligninadded to a negative electrode active material is set at 0.3 wt.%-1.0 wt.%, and an area of a grid of a battery grid body used for a negative electrode is set not more than 20 mm2. Here, an expanded grid body manufactured from a band-like material of lead or a lead alloy is preferably used as the battery grid body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cycle-use lead storage battery, and more particularly to an improvement of a negative electrode.

[0002]

2. Description of the Related Art In recent years, the use of lead-acid batteries has been expanding in various ways, and among them, lead-acid batteries have come to be used for applications requiring high output, such as those for electric vehicles. Therefore, improvement of high output performance, which has not been regarded as important in conventional applications and for electric vehicles such as electric tricycles and golf carts, is indispensable.

[0003] Regarding high output performance, the conventional lead-acid battery has a problem that the high-rate discharge characteristics are deteriorated early if charge / discharge cycles are repeated. This is considered to be caused by the negative electrode active material shrinking due to charge / discharge and a decrease in surface area. To prevent this, it has been proposed to add an organic expander such as lignin.

However, when lignin is added to improve the high rate discharge characteristics during the cycle life, more lignin is adsorbed on the surface of the negative electrode active material, and the reactivity decreases.
As a result, there has been a problem that the charge acceptability is reduced and the battery capacity is reduced due to insufficient charging.

To solve this problem, the amount of carbon added to the negative electrode active material must be optimized (Japanese Patent Laid-Open No. 9-21333).
No. 6) and adding tin metal to the negative electrode active material (Japanese Patent Application Laid-Open No. 5-89873) to supplement the charge acceptability.

[0006]

However, in order to suppress a decrease in charge acceptability, a new additive is introduced,
When the amount of the additive is increased, the amount of the negative electrode active material per volume is reduced, so that the battery capacity is rather reduced and the cycle life is shortened. In addition, the fluidity of the active material paste changes, causing problems such as difficulty in filling and short-circuiting due to dissimilar metals.

An object of the present invention is to solve such a conventional problem and to provide a lead-acid battery having excellent high-rate discharge characteristics and excellent life characteristics without deteriorating charge acceptability. It is assumed that.

[0008]

According to the present invention, in order to achieve the above object, the lignin in the negative electrode active material is reduced from 0.3% by weight to 1.0% by weight, and the grid area of the negative electrode grid is reduced to 20 mm. ² or less. With this configuration, high-rate discharge characteristics in cycle life are improved, and the current collecting property is improved without changing the type and amount of additives other than lignin, thereby suppressing a decrease in charge acceptability. Is what you do.

[0009]

Embodiments of the present invention will be described below.

For manufacturing an electrode plate, a strip-shaped sheet made of a rolled lead alloy is used.
A method was used in which a paste-like active material was continuously applied to an expanded lattice body which forms a cut in the material and develops an expanded grid. In the expanding method, a reciprocating method was used in which the mold cutter was moved up and down to make a cut in the belt-shaped sheet and developed at the same time. Conventional grid square area (150
Several types of lattices having a squared area smaller than mm ² ) were produced. For comparison, a conventional grid having a squared area was also prepared at the same time.

An amount of lignin shown in Table 1 and lead powder, barium sulfate, water and sulfuric acid are kneaded to prepare a paste-like active material, which is coated with the same weight of the active material and ripened. After drying, a negative electrode plate was obtained. A group was formed using these electrode plates, and the rated 12V60 of Examples 1 to 3 and Comparative Examples 1 to 5 were used.
An Ah battery was produced.

[0012]

[Table 1]

These lead-acid batteries were evaluated at 25 ° C. by a 1/3 CA discharge cycle life test. In this cycle life test, a constant current of 1/3 CA was applied to a discharge depth of 80%, and 2.5 CA was performed every 50 cycles.
At a constant current of 8.4 V to confirm the change in capacity. Charging was performed by two-stage constant current charging. In the second-stage constant current charging, the battery is charged up to 14.4 V with the first-stage charging current (0.2 CA), and then charged with the second-stage charging current (0.05 CA).
It is a method of charging for hours.

FIG. 1 shows the results of a 1/3 CA discharge cycle life test. It can be seen that the battery containing 0.3% by weight or more of lignin is about 1.2 to 2 times as large as the battery containing 0.2% by weight of Comparative Example 1.

Although the capacity decreases as the amount of lignin increases, the charge acceptability deteriorates.
The batteries of Examples 1 to 3 with m ² exceeded the target value. However, the battery of Comparative Example 2 containing 1.2% by weight of lignin could not meet the target value, and the life was shortened due to insufficient charging. In addition, 0.3% by weight of lignin
In Comparative Examples 3 to 5, the battery capacity was higher as the grid area was smaller, but even in Comparative Example 3 with a grid area of 50 mm ² , the peak capacity target value was not reached.

From the above results, even in a battery in which the amount of lignin is increased in order to obtain excellent high-rate discharge characteristics during charge / discharge cycles, the current collecting performance is improved by setting the grid area of the negative electrode grid to 20 mm ² or less. To reduce the decline in charge acceptability,
Battery capacity can be secured.

In this embodiment, the lattice body is formed by the reciprocating expand method. However, the lattice body is formed by a multi-layered disk-shaped cutter, and a slit is formed in the band-like sheet by a mold, and the other steps are performed. To expand to the specified width
The same effect can be obtained for a lattice body using the Tali expand method. In addition, effects can be obtained even when a conventional casting grid is used, and the present invention does not limit the grid body manufacturing method.

Although the present invention is effective also in a vented lead storage battery, it has an exothermic reaction such as an oxygen absorption cycle at the time of charging, and has a small amount of electrolytic solution and a small heat capacity, so that the temperature of the sealed lead easily increases. The effect is more remarkable in storage batteries.

[0019]

As is apparent from the above description, the lead storage battery according to the present invention can realize a higher rate discharge characteristic during the cycle life than the conventional one without lowering the charge acceptability.

[Brief description of the drawings]

FIG. 1 is a diagram showing a comparison result of discharge cycle life characteristics at 1 / 3C.

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Claims (2)

[Claims] 1. A lead characterized in that the amount of lignin added to the negative electrode active material is 0.3% by weight to 1.0% by weight, and the grid used for the negative electrode has a grid area of 20 mm ² or less. Storage battery. 2. A lead-like or lead-alloy band-shaped sheet is formed on a battery grid.
2. The lead-acid battery according to claim 1, wherein an expanded lattice processed from a metal material is used.