U.S. patent number RE36,734 [Application Number 08/787,661] was granted by the patent office on 2000-06-13 for battery plates having rounded lower corners.
This patent grant is currently assigned to Johnson Controls Technology Company. Invention is credited to Richard R.W. Binder, Daniel J. Cantillon, Jeffrey J. Schneider.
United States Patent |
RE36,734 |
Binder , et al. |
June 13, 2000 |
Battery plates having rounded lower corners
Abstract
A process for cutting a moving strip to form a series of plates,
such as battery plates, includes the initial step of transporting
the strip past a rotary divider including a cutter having radial
blades configured to cut the strip into the plates. The cutter
further has a set of blades for cutting individual pieces from the
strip, which pieces are not part of the plates. As the cutter
blades cut the strip to form the plates and pieces, a vacuum system
applies suction to draw the pieces cut from the strip inwardly into
the cutter through holes in the cutter, and then out of the cutter.
The holes are each located adjacent each one of the corresponding
blades and are shaped and positioned to permit the cut-away piece
to pass through. In a preferred embodiment, the vacuum system
includes a pair of vacuum manifolds that apply suction at opposite
ends of the cylindrical cutter. An apparatus for carrying out the
foregoing process accordingly includes a rotary divider as
described above provided with a vacuum system. Battery plates made
according to the foregoing process are improved in that the two
lower corners have a rounded shape lacking a sharp edge which tends
to tear an adjacent separator. Such a plate may be inserted bottom
end first into a separator envelope to form a plate element for use
in a lead-acid battery.
Inventors: |
Binder; Richard R.W. (Menomonee
Falls, WI), Cantillon; Daniel J. (Sussex, WI), Schneider;
Jeffrey J. (Waukesha, WI) |
Assignee: |
Johnson Controls Technology
Company (Plymouth, MI)
|
Family
ID: |
25426887 |
Appl.
No.: |
08/787,661 |
Filed: |
January 23, 1997 |
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
Reissue of: |
909247 |
Jul 6, 1992 |
05384217 |
Jan 24, 1995 |
|
|
Current U.S.
Class: |
429/225; 429/211;
429/234; 429/246 |
Current CPC
Class: |
H01M
4/82 (20130101); H01M 4/16 (20130101); H01M
4/73 (20130101); H01M 4/20 (20130101); Y10T
83/658 (20150401); Y10T 83/483 (20150401); Y10T
83/207 (20150401); Y10T 83/222 (20150401); Y02E
60/10 (20130101) |
Current International
Class: |
H01M
4/73 (20060101); H01M 4/64 (20060101); H01M
4/16 (20060101); H01M 4/20 (20060101); H01M
4/72 (20060101); H01M 4/82 (20060101); H01M
004/72 (); H01M 002/18 (); H01M 004/73 (); H01M
002/14 (); H01M 004/18 (); H01M 002/02 () |
Field of
Search: |
;429/225,234 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Higel; Floyd D.
Attorney, Agent or Firm: Quarles & Brady LLP
Claims
We claim:
1. In a battery plate for use in a lead-acid battery, the plate
comprising a conductive grid covered with an active lead material,
the grid comprising a generally rectangular outer frame having a
pair of sides, a top and a bottom spanned by grid elements forming
a mesh, the frame having a pair of upper corners, a pair of lower
corners, and an electrically conductive tab extending from a
location on the top of the frame between the two upper corners, the
improvement which comprises:
the plate has been formed by expanding a strip of lead alloy, and
the two upper corners are square and the two lower corners have a
rounded shape lacking a sharp edge which would tend to cut an
adjacent separator element, and the sides of the frame are
substantially straight and free of projections.
2. A plate element for use in a lead-acid battery, comprising:
a separator envelope joined along its sides and bottom end and
having an open upper end; and
a battery plate comprising a conductive grid formed by expanding a
strip of lead alloy and having an active lead material applied
thereto, which plate is inserted into the separator envelope bottom
end first, wherein the grid comprises a generally rectangular outer
frame having a pair of sides, a top and a bottom spanned by grid
elements forming a mesh, the frame having a pair of upper corners
and a pair of lower corners, with an electrically
conductive tab extending from a location on the top of the frame,
the plate being substantially completely inserted into and covered
by the envelope except for the tab, which extends out of the open
upper end of the envelope, and the two lower corners of the plate
have a rounded shape lacking a sharp edge which would tend to cut
the separator envelope.
3. The plate of claim 1, wherein the tab extends from a location
between and spaced from the two upper corners.
4. The plate element of claim 2, wherein the upper corners of the
frame are square.
5. The plate element of claim 4, wherein the sides of the frame are
substantially straight and free of projections.
6. The plate element of claim 2, wherein the separator envelope has
substantially the same shape as the frame and is sealed along its
bottom and sides so that the frame fits closely therein with the
tab projecting out of the open upper end of the separator
envelope.
7. The plate element of claim 6, wherein the separator envelope
consists essentially of polyethylene.
8. The plate element of claim 7, wherein the separator envelope
consists essentially of a single piece of polyethylene folded in
half along a bottom edge thereof and crimped along its sides.
9. The plate element of claim 4, wherein the tab extends from a
location between and spaced from the two upper corners. .Iadd.
10. A battery plate for use in a lead-acid battery, the plate
comprising:
a conductive grid formed by expanding a strip of lead alloy and
covered with an active lead material, the grid having a generally
rectangular shape including a top and a bottom and sides, the top
and bottom being spanned by grid elements formed a mesh and the
sides being substantially straight and free of projections, the
grid having a pair of substantially square upper corners formed in
the top, and a pair of rounded lower corners formed in the bottom,
and a conductive tab extending from a location on the top between
the two upper corners. .Iaddend..Iadd.11. A battery plate for use
in a lead-acid battery, the plate comprising:
a conductive grid formed by expanding a strip of lead alloy and
covered with an active lead material, the grid having a generally
rectangular shape including a top and a bottom and sides, the top
and bottom being spanned by grid elements forming a mesh and the
sides being open cut mesh and substantially straight and free of
projections, the grid having a pair of substantially square upper
corners formed in the top, and a pair of rounded lower corners
formed in the bottom, and a conductive tab extending from a
location on the top between the two upper corners.
.Iaddend..Iadd.12. A battery plate for use in a lead-acid battery,
the plate comprising:
a conductive grid formed by expanding a strip of lead alloy and
covered with an active lead material, the grid having a generally
rectangular shape including a top and a bottom, the top and bottom
being spanned by grid elements forming a mesh, the grid having a
pair of substantially square upper corners formed in the top, and a
pair of rounded lower corners formed in the bottom, and a
conductive tab extending from a location on the top between the two
upper corners, and
a separator substantially completely enveloping the plate except
for the tab which extends from an open portion of the separator,
the separator being sealed at least along side portions thereof so
that the plate fits closely therein. .Iaddend.
Description
TECHNICAL FIELD
The present invention relates to the manufacture of plates from a
moving strip by cutting the strip, particularly to the manufacture
of battery plates for use in lead-acid batteries.
BACKGROUND OF THE INVENTION
A plate for a lead-acid battery is conventionally made by applying
a battery paste to a conductive support such as a lead alloy grid.
The paste is made from lead oxide, sulfuric acid and water. The
lead oxide reacts with the sulfuric acid to form mono-, tri- or
tetrabasic lead sulfate(s). Dry additives such as fiber and
expander may be added. The mixture is then dried and water is
re-added to form a paste of the desired consistency. The paste is
applied to the lead grid, and the pasted plates are then
flash-dried and cured at an elevated temperature and humidity to
oxidize free lead and adjust the crystal structure of the plate.
After curing, the plates are assembled into batteries and
electrochemically formed by passage of current to convert the lead
sulfate or basic lead sulfate(s) to lead dioxide, thereby forming
the active lead material.
The lead alloy grid is made in a multistage process in which molten
lead alloy is cast to form a strip. The strip is expanded to form
mesh elements for grids, and the paste is then applied. Liner
papers are applied to the surfaces of freshly pasted plates during
the pasting operation to facilitate handling and stacking.
Individual plates are formed by passing the pasted strip through a
rotary divider that cuts the outlines of the individual plates on
the moving strip. To ensure proper registration for cutting, the
strip is formed during expansion with a series of regularly spaced
central recesses that are engaged by lugs of a drive roller
associated with the divider. The cut plates are then flattened,
flash-dried, and stacked for later use in lead-acid battery
manufacture.
The battery grids each take the form of a generally rectangular
frame supporting a mesh of grid elements onto which the paste is
applied. The frame has a pair of upper corners and a pair of lower
corners, and an electrically conductive tab extending from a
location between the two upper corners. In one common battery
design, every other plate in the battery stack is inserted into an
envelope made of a separator material such as submicro
polyethylene. The sides of the envelope act as separators between
the plate in the envelope and the two adjoining plates in the
battery stack.
In assembling a battery of this kind, it is necessary to insert the
battery plate bottom-first into the open end of the envelope so
that the conductive tab at the top of the plate extends out of the
envelope. However, the bottom corners on the battery plates are
sharp, and will snag and tear the separator material between the
positive and negative plates, causing an electrical short within
the battery and reducing battery life. Bending or vibration of the
plate disposed in the envelope during assembly or use can also
cause tearing, and the problem is not confined to envelope-style
separators.
Use of battery plates with rounded bottom corners would eliminate
the snag and tearing of separators, but no practical process has
been proposed for producing rounded corners on such battery plates.
In particular, any process wherein the rotary divider cuts off
corners results in small pieces of trim (scrap) that are severed
from the strip. These pieces, if left on the strip after cutting,
can come loose and cause cutting die failure on the divider and can
lead to battery failure if the pieces are carried over and
inadvertently incorporated into the finished battery. The present
invention addresses these problems by providing a system for
cutting the rounded corners and then removing the pieces during
continuous plate manufacture.
SUMMARY OF THE INVENTION
A process for cutting a moving strip to form a series of plates,
such as battery plates, initially involves transporting the strip
past a divider having a rotary cutter with a first set of blades
extending radially therefrom configured to cut the strip into the
plates, and a second set of radial blades for cutting individual
pieces from the strip. As the blades cut the strip to form the
plates and pieces, a vacuum system applies suction to draw the
pieces cut from the strip inwardly into the cutter through holes in
the cutter, and then out of the cutter. The holes are each located
adjacent one of the corresponding cutter blades of the second set
and are shaped and positioned to permit the cut-away piece to pass
through. In a preferred embodiment, the vacuum system includes a
pair of vacuum manifolds that apply suction at opposite ends of the
cylindrical cutter.
An apparatus for carrying out the foregoing process accordingly
includes a rotary divider having a cylindrical cutter configured to
cut the strip into the plates, including a second set of blades for
cutting individual pieces from the strip as described above, and a
vacuum system that applies suction to draw the pieces cut from the
strip inwardly into the cutter through the holes in the cutter, and
then out of the cutter.
According to a further aspect of the invention, a conventional
battery plate as described above is improved in that the two lower
corners have a rounded shape lacking a sharp edge which would tend
to tear an adjacent separator. Such a plate may be inserted bottom
end first into a separator envelope to form a plate element for use
in a lead-acid battery.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be described with reference to the accompanying
drawings, wherein like numerals denote like elements, and:
FIG. 1 is a schematic diagram of an overall process for making
battery plates in which the process of the invention is included,
with the shape of the strip at each stage shown below;
FIG. 2 is a schematic diagram of a vacuum system used with a
divider according to the invention;
FIG. 3 is a schematic side view of the divider and flattener
apparatus used in the process of FIG. 1;
FIG. 4 is a perspective view of a divider apparatus according to
the invention;
FIG. 5 is a partial perspective view of the cylindrical cutter
shown in FIG. 4;
FIG. 6 is partial front view, partly in section, of the left end of
the divider shown in FIG. 4; and
FIG. 7 is a front view of a battery plate element according to the
invention, with the concealed portion of the plate shown in
phantom.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Referring to FIG. 1, the process according to the invention is
shown in relation to the other steps conventionally used in a
continuous process for making lead-acid battery plates. The known
process for making such plates includes an initial step 21 of
melting hog lead in a furnace, followed by a step 22 of feeding
molten lead alloy to a strip caster. Trim from the caster is
recycled to the furnace. The strip is coiled (23) on a winder, and
coils of lead alloy strip are stored for later use.
To form a battery grid, the coil is unwound (24) and the free end
is fed through an expander that cuts, slits and stretches (25) the
strip to form a mesh-like pattern of grid elements. See, for
example, the expanders described in U.S. Pat. Nos. 4,315,356 and
4,291,443 assigned to Cominco Ltd., the contents of which are
incorporated herein by reference. Trim from the expander is
recycled to the furnace. The expanded strip is then pasted (26) by
a conventional paster, and then fed to the divider according to the
invention, wherein the strip is cut (27). Plates cut from the strip
are then flattened (28), then passed on a conveyer through an oven
for flash-drying (29), and then stacked (30) for later use. Flash
drying is performed using an open gas flame or an oven, for
example, as a 10-15 second drying of the plates in a conventional
blast drying oven at 260.degree. C. (500.degree. F.).
A shown in FIG. 2, a rotary divider 31 used in the cutting step has
a vacuum system 32 associated therewith. Divider 31 cuts the moving
strip into plates and, at the same time, cuts rounded corners as
explained in detail below. Each pair of corners cut results in a
small, roughly triangular piece of trim (scrap metal.) Vacuum
system 32 includes a cyclone blower 33 connected to a cyclone 34 by
a conduit 35. Cyclone 34 is in turn connected to a pair of
manifolds 36 disposed at opposite ends of divider 31 through a pair
of hoses or pipes 37. The trimmed pieces from divider 31 enter
manifolds 37 and pass through hoses 37 into cyclone 34. The pieces
then fall out of the bottom of cyclone 34 into a barrel 38. The
contents of barrel 38 may be periodically recycled to a
smelter.
Referring now to FIGS. 3 and 4, the divider 31 is located
immediately ahead of a flattener 39. A pasted strip 41 has a series
of regularly spaced holes 42 which are engaged by lugs or dogs 43
of an optional first drive roller 44. Roller 44 may comprise a
series of spaced, coaxial disks of equal diameter that receive
strip 41 from the paster, with lugs 43 being on the center disk.
Strip 41 then moves over several spaced, parallel support rails 46
into a nip 47 between a second drive roller 48 and a cylindrical
cutter 49.
Cutter 49 simultaneously cuts strip 41 into two rows of battery
plates 41A having rounded outside (bottom) corners 51. A
freely-rotatable rotary brush 52, for example, a 2-inch diameter
nylon brush, contacts the cylindrical outer surface of cutter 49
tangentially, preferably from end to end, cleaning it and aiding in
forcing the trim pieces into the interior of cutter 49. All of
rolls 44, 48 and 49 are driven by a suitable drive system 53 such
as an electric motor provided with a gear linkage (not shown) that
ensures that rolls 44, 48 and 49 rotate together at the same
speed.
Flattener 39 includes pair of upper and lower conveyer belts 56, 57
wound over a series of spaced pairs of upper and lower rollers 58,
59 and spaced apart by a distance approximately equal to the plate
thickness, e.g., 0.04 inch. The plates 41A are fed between belts
56, 57. The action of rollers 58, 59 flattens out any raised edges
which may have formed during cutting. Rollers 58, 59 have an
associated drive system but need not be biased to exert extra
pressure on plates 41A.
FIGS. 4 to 6 illustrate the divider 31 in detail. Rotary cutter 49,
which is preferably a cylindrical drum, has a plurality of cutter
blades 61 projecting radially from its cylindrical surface in a
repetitive pattern that forms two offset rows of plates 41A. Blades
61 include lengthwise blades 61A that form the sides of each plate
41A, central transverse blades 61B for forming the tab on each
plate, and rounded blades 61C for forming the rounded lower corners
of each plate. Blades 61B alternate with a row of central recesses
62 that mate with lugs 43 of drive roller 48, and blades 61B
alternately face in opposite directions to produce two rows of
plates 41A from a single strip as shown. Blades 61A extend from one
end of a blade 61B alternately in offset positions towards each end
of the roll, at which point each blade splits into a pair of
curved, symmetrical blades 61C. Each pair of blades 61C cuts off a
roughly triangular piece from strip 41 to form a pair of rounded
corners 51.
Rotary cutter 49 has a pair of axles 63 projecting from its ends
rotatably supported by a pair of bearings 64; drive roller (cutting
anvil) 48 is similarly supported. Cutter 49 further has a pair of
annular recesses 65 in each end. Each recess 65 communicates with a
series of spaced radial holes 66 each formed adjacent to and
outwardly of an associated pair of cutter blades 61C. Holes 66 are
large than the pieces trimmed by the blades 61C.
The vacuum manifolds 36 are mounted in contact with the rotating
ends of cutter 49 covering each recess 65. Each manifold comprises
a pair of mating sections 36A, 36B which are secured together by
any appropriate means, such as screws or other fasteners, on
opposite sides of each axle 63. Sections 36A, 36B have semicircular
cutaway portions which form a manifold chamber 65A in communication
with recess 65. An outlet opening 65B in one section 36B allows
cut-away corner pieces 67 to pass through a manifold extension 70
having a gradually reduced width, and then into hose 37, which is
coupled to extension 70. For purposes of removing corner pieces 67
from lead-acid SLI battery plates of conventional size, a minimum
vacuum of about 9 inches of water is needed. If the process line is
operating at a speed higher than about 100-130 feet/minute, a
stronger vacuum may be needed.
In operation, cutter 49 rotates to continuously cut plates 41A as
described above. Triangular trim pieces 67 are cut away from strip
41 by rounded blades 61C. These pieces 67 are drawn inwardly
through holes 66 by the suction applied by vacuum system 32 through
manifolds 36. If the suction is not sufficient to make each piece
67 fall in, brush 52 contacts pieces 67 and presses them inwardly
in combination with the force of the suction. Pieces 67 enter
annular recess 65 and the associated manifold 36, after which they
travel to barrel 38 via manifold chamber 65A, outlet 65B, manifold
extension 70, hose 37 and cyclone 34, as described above.
FIG. 7 illustrates a plate element 71 according to the invention
including a pasted plate 41A having rounded bottom corners 51,
square top corners 72, and a conductive tab 73 extending from
between the top corners 72. The grid itself includes a generally
rectangular outer frame 74 and a mesh of grid elements 75 (see FIG.
1) spanning frame 74 which are covered by the battery paste. Many
different grid designs are well-known in the art. Each plate 41A is
disposed in a conventional submicro polyethylene separator envelope
76. Envelope 76 is formed from a single piece of material which is
folded in half and secured at the edges, for example, with crimped
edges 77. During insertion or re-insertion of plate 41A into
envelope 76, such as during the strap forming operation, rounded
corners 51 prevent tearing of envelope 76.
It will be understood that the foregoing description is of
preferred exemplary embodiments of the invention, and that the
invention is not limited to the specific forms shown. For example,
the process and apparatus according to the invention could be used
to manufacture virtually any type of plate, and are not limited to
the manufacture of battery plates. The holes, blades and recesses
of the cutter could be rearranged to cut away small pieces at
locations other than the bottom corners as disclosed. These and
other modifications may be made in the design and arrangement of
the elements without departing from the scope of the invention as
expressed in the appended claims.
* * * * *