Metal working – Battery-grid making
Reexamination Certificate
1998-08-27
2001-06-12
Nuzzolillo, Maria (Department: 1745)
Metal working
Battery-grid making
C029S006100, C029S006200, C029S623100, C429S233000, C429S242000
Reexamination Certificate
active
06243932
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a manufacturing method of expanded grid used in a storage battery, and a manufacturing apparatus of expanded grid.
BACKGROUND OF THE INVENTION
Generally, an expanded grid used as the core of an electrode of a storage battery is manufactured in a step of forming parallel intermittent cuts in the width direction in a surface of a region excluding the central portion of a thin plate in a band form made of metal such as lead or lead alloy continuously in a zigzag form, and a step of expanding and developing the thin plate having cuts in the width direction. The expanded grid used widely as the grid for electrode plates of a lead acid storage battery is superior to the casting grid in the mass producibility, and is suited to the lead acid storage batteries of mass-produced automobiles. Recently, a higher performance is demanded in the batteries, and it is required to reduce the mesh size of the grid in order to enhance the current collecting effect of the grid.
However, in such an expanded grid, the width is developed by extending the cuts sequentially. As a result, the track distance at the outermost side of the band metal plate is longer than the track distance in the central portion. Accordingly, creases are formed when developing the thin plate having cuts in a flat plane, and the creases cause deflection, which yield periodic creases in the developed grid. Due to such creases, the width dimension of the grid becomes unstable. As a result, adjusting the manufacturing condition becomes a labor-intensive task. Furthermore, the dimensional precision of the electrode plate is not stable, and the quality fluctuations are significant. In addition, a local distortion occurs in the grid which is likely to promote grid corrosion. Such phenomenon occurrs more prominently in the grid with the smaller mesh size.
SUMMARY OF THE INVENTION
A manufacturing method for an expanded grid of the invention includes:
(a) a step of supplying a thin plate of band form from the longitudinal direction,
(b) a step of forming a plurality of intermittent cuts parallel to the edge in a first region, excluding a second region, of the thin plate of band form, and,
(c) a step of expanding and developing the cuts in the width direction,
while moving sequentially in the longitudinal direction the thin plate having the first region forming the plurality of cuts and the second region not having the cuts,
in which the outermost side portion of the first region moves a first track distance when expanding the cuts, the second region moves a second track distance, and the first track distance and the second track distance are nearly the same distance.
Preferably, the manufacturing method further includes:
(d) a step of bending the second region at a desired angle,
in which as the thin plate having the cuts and bent at the angle moves sequentially in the longitudinal direction, the cuts are expanded and developed in the width direction, so that the first track distance and the second track distance are nearly the same distance.
Preferably, the second region is a central portion of the thin plate of band form, the first region is both side portions of the central portion, and the central portion is bent at a position for terminating the expansion of the outermost side portion.
A manufacturing apparatus for an expanded grid of the invention includes:
(a) a processing means for forming a plurality of intermittent cuts parallel to the edge of a thin film of band form, in a first region, excluding a second region, of the thin plate of band form,
(b) developing means for expanding and developing the cuts in the width direction, while moving sequentially in the longitudinal direction the thin plate having the first region forming the plurality of cuts and the second region not having the cuts, and
setting means for setting a first track distance of outermost side portion of the first region moving when expanding the cut nearly at a same distance as second track distance of the second region.
Preferably, the setting means is a bending means for bending the second region at a predetermined angle.
Preferably, the second region is a central portion of the thin plate of a band form, the first region is both side portions of the central portion, and the central portion is bent at a position for terminating the expansion of the outermost side portion.
In this embodiment, the occurrence of creases due to plane distortion is prevented, and the width dimension of the grid is stabilized. These effects are enhanced. When manufacturing a grid with a smaller mesh size. The local stress concentration of the grid is alleviated. As a result, the quality of the electrode plate using such grid is enhanced. Hence, the battery using the grid of the invention presents an excellent life characteristic, and a stable performance having only small performance fluctuation width. Moreover, by using a grid with a smaller mesh size, the storage battery will achieve excellent charging and discharging characteristics.
REFERENCES:
patent: 3867200 (1975-02-01), Daniels, Jr.
patent: 4221032 (1980-09-01), Cousino et al.
patent: 4303747 (1981-12-01), Bender
patent: 0 682 378 (1995-11-01), None
patent: 2 200 069 (1988-07-01), None
European Search Report corresponding to application No. EP 98 30 6445 dated Dec. 14, 1998.
Iwamura Akira
Kashio Go
Dove Tracy
Matsushita Electric - Industrial Co., Ltd.
Nuzzolillo Maria
Ratner & Prestia
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