JP2002110172A - Lead acid battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a positive electrode plate from breaking through a separator due to growth and a broken bending main frame touching a negative electrode plate from short-circuiting while using a battery. SOLUTION: The present invention is a lead acid battery characterized in that the positive electrode plate makes use of an expanded metal grating 11 and characterized in that the expanded metal grating 11 is cut at an outside corner 4a and inside corner 4b of the main frames 3a and 3b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead storage battery, and more particularly to an expanded grid used as a current collector for a positive electrode plate.

[0002]

2. Description of the Related Art A lead storage battery used as a power supply is:
Usually, it is a monoblock battery in which a plurality of cells (unit cells) are assembled and integrated. This monoblock battery generally has a rectangular parallelepiped resin container formed by partitioning the inside into a plurality of cell chambers, a group of electrodes disposed in each of the cell chambers, and an upper opening of the container. And a closing lid. The electrode group is formed by laminating a plurality of positive plates and negative plates with a separator holding an electrolyte interposed therebetween, and ears of the plurality of positive plates are integrally connected by a positive electrode strap, and a plurality of negative plates are formed. Are integrally connected by a negative electrode strap. A positive electrode pole is provided so as to protrude from the positive electrode strap toward the opening of the lid, and a negative electrode pole is provided so as to protrude from the negative electrode strap toward the opening of the cover. .

[0003] In such a monoblock battery, a cast product has conventionally been used for a lattice body. In recent years, however, in order to improve productivity, a sheet made of lead or a lead alloy is processed into a lattice shape by an expander. The use of expanded lattices has increased.

[0004] Such an expanded lattice body has ribs at the top and bottom or left and right, and a mesh-like lattice portion is formed between the ribs. To produce this lattice, the sheet is cut and stretched. For this reason, the corners of the ribs are formed substantially at right angles. In general, a lead storage battery is corroded during use, and so-called growth occurs in which a grid of a positive electrode plate extends outward of the electrode group. At this time, particularly the corners of the grid of the positive electrode plate are easily stretched. Moreover, in the expanded lattice body, since the ribs have a substantially right angle, the extended portion is easily sharpened. As a result, as shown in FIG. If the separator 1 comes in contact with the strap 2 or the separator 1 is a packaging separator, it breaks through the separator and comes into contact with the side of the negative electrode plate to cause a short circuit. Further, even when the packaging separator is not used, there is a problem of causing a short circuit as described above.

[0005] In order to solve such a problem, for example, as disclosed in Japanese Utility Model Laid-Open No. 55-158575, the upper part of the rib near the counter electrode strap is inclined to prevent a short circuit with the counter electrode strap. ing. Alternatively, JP-A-9-63
As disclosed in Japanese Patent No. 591, a method has been devised such that the corners 4a of the outer peripheral portions of the ribs 3a and 3b are cut out so that both ends of the ribs 3a and 4b are hard to contact the adjacent negative electrodes. (See Fig. 4)

[0006]

However, even in a battery using a lattice body having such a shape, as the growth progresses during use of the battery, the inner corners 4b of the ribs 3a and 3b also extend outward, so that the packaging is not performed. There has been a problem that the separator pierces or bends and reaches the negative electrode to cause a short circuit, resulting in a short life.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a long-life lead-acid battery.

[0008]

According to the present invention, not only the outer corners 4a but also the inner corners 4b of the ribs 3a and 3b of the expanded lattice body 11 of the lead-acid battery are cut off to solve the above-mentioned problems. It is characterized by the following. Note that these corners 4a, 4
It is not always necessary to cut out all of b, but it is preferable that the corners 4a and 4b of the upper rib 3a that are farther from the ear 7 are cut off.

[0009]

Embodiments of the present invention will be described below.

As shown in FIG. 1, the expanded lattice body for a positive electrode plate according to the present invention is made of a square lead alloy sheet, and has ribs 3a and 3b at the top and bottom, and a mesh-like lattice portion 6 between them. The upper rib 3a has an ear 7 protruding upward from one position of an upper side 8, and the upper side 8 is gradually tapered from the middle toward one end (the right end in the figure).
The two ribs 3a and 3b are cut at two corners at both ends to form inclined portions 9 and 10. This slope 9,10
Does not necessarily have to be inclined, and may have a rounded shape, for example.

A positive electrode plate is produced by subjecting such a lattice body to ordinary kneading, drying and aging steps. This positive electrode plate is wrapped with a packaging separator, and a plurality of conventional negative electrode plates which are not wrapped with the packaging separator are alternately arranged, and the electrode plates having the same polarity are connected to each other by a strap having a pole at an upper portion to form a pole group.
This electrode group is housed in a cell chamber in a battery case, the pole is fitted into the opening of the lid, and the lid and the battery case are welded or bonded to produce the lead storage battery of the present invention.

In the present embodiment, the positive electrode plate is wrapped with the wrapping separator, but a flat separator may be used.

Further, the present invention relates to the shape of the positive electrode grid body, and the shape of the negative electrode grid body is not particularly limited, and the type of the battery is controlled valve type or liquid type. Not limited.

[0014]

Embodiments of the present invention will be described below.

An expanded lattice body 11 according to the present invention shown in FIG. 1 and made of a Pb—Ca—Sn based alloy, and a Pb—C
A positive electrode plate was prepared by using a conventional expanded lattice body made of an a-Sn-based alloy as shown in FIG. 4 as a current collector of a positive electrode, through kneading, drying and aging processes. At this time, in order to process the expanded lattice body into the shape shown in FIG. 1, for example, the corners of the ribs are cut out to form inclined portions 9 and 10 by punching at the time of a node press.

Next, a control valve type lead-acid battery A having a rated capacity of 12 A and a rated capacity of 60 Ah (three-hour rate capacity) was prepared using the former positive electrode plate. Also, using the latter positive electrode plate, the same voltage as the battery A,
A control valve type lead storage battery B having the same capacity was produced. These two types of batteries A and B have the same configuration as the conventional battery except that the shape of the lattice used for the positive electrode is different.

Using the two types of batteries A and B, a life performance evaluation test was performed.

The cycle test condition during the life test is 1 / 3C
The battery was discharged at a current corresponding to A to 48 Ah, charged at a current corresponding to 0.5 CA to 2.4 V / cell, and then charged to a current of 0.05 CA to 110% of the discharge capacity. The ambient temperature was 25 ± 2 ° C.

Every 50 cycles during the cycle test,
A capacity test was conducted to discharge to 1.65 V / cell at a current equivalent to 1/3 CA. The result is shown in FIG. After the capacity test, the battery was charged to a current of 0.5 CA up to 2.4 V / cell, and then charged at a current of 0.05 CA to 110% of the discharge capacity.
Ambient temperature is the same as during the cycle test.

As shown in FIG. 2, the life of the conventional battery B was 450 cycles, but the life of the battery A according to the present invention was extended to 550 cycles.

Further, when 450 cycles of these two types of batteries A and B had elapsed, one battery was removed and dismantled, and the state of the lattice was observed. As a result, in the battery B, the growth was confirmed in the portion of the lattice body far from the ear, and
3a was not in contact with the strap part, but the upper rib 3a
Of the negative electrode broke the separator, and a short-circuit occurred with the side of the negative electrode plate. On the other hand, in the battery A, although the lattice was grown, the separator was not damaged and no short circuit occurred.

The present invention relates to the shape of the grid of the electrode plate, and in the embodiment, the Pb-Ca-Sn-based alloy has been described. Similarly, the effects of the present invention can be obtained, and the invention is not limited to the Pb-Ca-Sn-based alloy.

[0023]

As described above, according to the present invention, since the corners of the ribs of the expanded lattice constituting the positive electrode plate are cut off, the separator is damaged even if the ribs are extended during use of the battery. This prevents the battery from being short-circuited or wrapping around the side portion of the separator and short-circuited by contact with the counter electrode, thereby providing a long-life lead-acid battery.

[Brief description of the drawings]

FIG. 1 is a plan view showing an embodiment of a lattice body according to the present invention.

FIG. 2 is a graph showing the life performance of the battery of the present invention and a conventional battery.

FIG. 3 is a plan view showing an embodiment of a grid of a conventional battery.

FIG. 4 is an explanatory view showing a state where a lattice body of a conventional battery has grown.

[Explanation of symbols]

 3a Upper rib 3b Lower rib 4a Outer corner 4b Inner corner 11 Grid

Claims (1)

[Claims] 1. An expanded grid 1 as a current collector of a positive electrode plate.
In the lead-acid battery using No. 1, the lattice body 11 is
A lead storage battery characterized in that an outer corner 4a and an inner corner 4b of 3a and 3b are cut off.