Note: Descriptions are shown in the official language in which they were submitted.
1 60BA-262
DESCRIPTION
BATTERY WITH IMPROVED TERMINAL STR~CTURE
. _ _
AND ~ETHOn OF MANUFACTURE
. ____
Technical Field
The present invention relates to the structure and
method of manufacture of batteries and particularly
concerns a battery having an improved terminal geome-try
and a method of manufacturing such a battery.
Background Art
For a number of years, nickel-cadmium and other types
of batteries have been manufac-tured by winding on an arbor
a sandwich of a positive plate, a negative plate and
separator materials, to produce a battery core. For some
battery types, the positive and negative plates are axially
offset relative to one another so that the edge of a plate
of one polarity projects from one end of the core and
the edge of a pla-te of the opposi-te polari-ty projects
from the o-ther end of the core. Percussive welding
procedures have been used to attach terminal tabs to the
opposite ends of such battery cores, after which the core
and tab assembly have been inserted into a surrounding
metal container. Then~ by inserting a welding electrode
through a bore left in the center of the core upon its
removal from the winding arbor, the terminal tab at the
bottom of the core has been welded to the bo-ttom of -the
container~ The terminal -tab at the top of the core has
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~9 ~ ~ 60-BA-262
subsequently been connected to an appropriate cover
assembly in the familair manner~
Although this method of manufac-ture produces
batteries which are quite suitable for their intended
applications, the method has typically required a
considerable amount of manual labor to complete the
~inding of the cores~ the attaching of the -terminal tabs
and the inserting of the assembled core and tabs into the
battery container. A need has existed for some time to
simplify the structure of -the batteries to facilitate
automatic manufacture and assembly of their component parts.
Disclosure of the Invention
An object of the present invention is to provide an
improved battery of the type comprising a container
surrounding a spiral wound core.
A further object of the present invention is to provide
an improved terrninal tab for use in such a battery, the tab
being configured so as to eliminate the need to weld the
tab to the battery container.
Still another object of the present invention is to
pxovide an improved, simplified method of manufacturing
such a battery.
These objects of the invention are given only by way
of example. Thus, other desirable objectives and advantages
inherently achieved by the disclosed invention may occur
or become apparent to those skilled in the art. Nonetheless,
the scope of the invention is to be limited only by the
appended claims.
The improved terminal tab according to the invention
is particularly suited for use in batteries of the type
comprising a cylindrical container surrounding a spiral
wound core having a cylindrical side wall and opposite ends.
A terminal tab is attached to each end of the core to provide
electrical connec:tions to other parts of the battery. The
terminal tab comprises an electrically conductive base
portion adapted on one side thereof -to be attached to an end
60BA-262
-- 3
of the core. An elongated tab member extends outwardly
from the other side of this ba~e portion and is adapted
to be bent back along the base portion, around the
circumferential edge or corner of the core and into contact
with the side wall of the core. Operatively associated
with the base portion and the tab member is a means for
minimizing compression by the tab member of this edge of
corner~ Absent this means, insertion of the core and
terminal tab into the battery container could cause the
bent tab member to compress the edge or corner of the
core sufficiently to result in a short circuit between the
positive and negative plates of the core. In the assembled
battery, the tab member is captured between the battery
container and the side wall of the core, thus ensuring
sufficient electrical contact.
In the preferred embodiment of the invention, the means
for minimizing compression of the edge or corner of the
comprises at least one protrusion on the base portion, this
protrusion extending outwardly from the base portion in
position to contact the tab member when the tab member is
bent back along the base portion. As a result, a space is
maintained between the tab member and the edge or corner
of the core so that unwanted compression is minimized.
Although it is preferred to provide this protrusion on the
base portion, it may also be provided on the tab member.
Also, the functlon of the protrusion may be provided by a
separate spacer positioned between the tab member and -the
portion.
The method according to the invention concerns
assembling an electrical bat-tery of the type comprising
a container surrounding a spiral wound core having a
cylindrical side wall and opposite ends. At least one
electrically conductive terminal tab is provided which
comprises a base portion adapted to be attached on one
side thereof to an end of the core, an elongated tab
member extending outwardly from the other side of the base
60BA-262
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portion and means operatively associated with the base
portion for minimizing compression by the tab member
of the edge or corner of the core. This terminal tab is
attached to an end of the core so that electrical contact
is made with at least one plate of a single polarity.
Then/ the tab member is bent back along the base portion
and into contact with the means for minimizing compression
and the side wall of the coil The coil and terminal tab
assembly is then inserted into the battery container so
that the outer end of the tab member is captured between
the container anA the side wall of the core and com-
pression of the edge of the core is minimized.
Descrip-tion of the Drawings
Figure 1 shows a perspective view of a type of prior
art terminal tab.
Figure 2 shows an elevation of a spiral wound battery
core to which a terminal tab of the type shown in Figure
1 has been attached.
Figure 3 shows an elevation section view of a
battery comprising a core and terminal tabs of the type
shown in Figure 2.
Figure 4 shows a perspective view of a terminal tab
according to the present invention.
Figure 5 shows a section view taken along lines 5-5
of Figure 4.
Figure 6 shows an elevation view of a spiral
wound battery core to which a pair of terminal -tabs
according to the invention have been attached.
Figure 7 shows an enlarged view of -the bottom end
of the core illustrated in Figure 6.
Figure 8 shows an elevation section view of a
battery embodying the core and terminal tabs illustra-ted
in Figure 6.
Bes-t Mode for Carrying Out the Invention
The following is a detailed description of the preferred
embodiment of the invention, reference being made to the
60BA-~62
-- 5
drawing in which like reference numerals identify like
elements of structure in each of the several E'igures.
Figure 1 shows a perspective view of a terminal
tab 10 of a type known in the prior art. A more or less
U shaped base portion 12 includes a pair of parallel leg
portions 14, 16 having a transverse space therebetween.
This space is chosen so that leg portions 14, 16 will
straddle the central bore B left in the ba-ttery core
following its removal from the winding arbor. (See
Figure 7, for example) Leg portions 14, 16 extend from
a rectangular base portion 18 and include a pair of down-
wardly extending contact edges 20, 22 which engage the
coiled edge of the battery plate when the terminal tab is
precussion welded to the wound core. An integral tab member
24 extends outwardly from edge 26 of base portion 18 and has
essentially parallel side edges 28 and an ou-ter end 30.
Typically, such a terminal tab 10 is made from nickel or
nickel~plated steel and is s-tamped from thin sheet stock.
Figure 2 shows a spiral wound battery core 32 of
conventional type. Such cores are made by assembling a
sandwich of a postive plate, a negative plate and separator
materials; axially offsetting the plates so that a plate
of one polarity extends from ore side of the sandwich and
a plate of the opposite polarity extends from the other
side of the sandwich; and then winding the sandwich on an
arbor to produce a spiral core. A length of -tape 34 can be
used to keep core 32 :Erom unwinding prior -to insertion in
the battery container. A posi-tive terminal tab 36, of
essentially the same geometry as that shown in Figure 1,
is percussion welded to the positive end of -the battery
and a terminal tab 10 is percussion welded to the negative
end. Tab 24 is then bent to a position essentially
parallel to the end of the core. Thereafter, the assemblied
core is inserted into a cylindrical metal con-tainer 38
of the type shown in Figure 3. To ensure aood electrical
contact between terminal tab 10 and the bottom of container
6OBA-262
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38, a welding el.ectrode is passed through the central
bore of the core and in-to contact with tab 24. When a
further electrode contacts the outside of container 38, a
welding current may be passed through tab 24 to comple-te
the connection. Assembl.y of the battery is completed
by inserting an insulator assembly 40 and a cover and
seal assembly 42, the latter of which makes contact with
terminal tab 36 as shown in Figure 3. Electrolyte is
added prior to closing the cell.
The improved battery terminal tab illustrated in
Figures 4 and 5 permits simplified assembly of a battery
by eliminating the need to weld the tab member 24 to
container 38. Since access through the central bore B of
the battery core is no longer required, a smaller winding
arbor can be used so that somewhat longer positive and
negative plates may be used to provide more active area.
In the terminal tab illustrated in Figures 4 and 5, body
portion is provided with an extension 44 which extends
away from the openiny between leg portions 14, 16. On
the outer surface of extension 44 r an elongated, centrally
located protrusion 46 is formed. r~hen the terminal tab
is made from 0.007 - 0.008 inch nickel sheet, protrusion
46 preferably has an overall height h of approximately
0.010 inch, an overall length ~- of approximately 0.250
inch and a transverse width w of approximately 0.040 inch.
Different shapes or more than one protrusion also may be
provided~ The function of protrusion 46 is to minimize
compressi.on by tan member 24 of the circumferential edge
or corner of bat-tery core 32 when the core is inserted
into container 38 and the outer end of tab member 24 is
captured between the container and the side wall of the
core. Although it is preferred that protrusion 46 be
provided on extension 44 of body portion 18, it is also
~ithin the scope of the invention to provide the protrusion
on the lower portion of tab member 24 or to provide a
separate spacer element to be posi-ti,oned between tab
L7t ~ ~ ~
60BA-262
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member 24 and body portion 18 when tab memher 24 is bent
back along body portion 18~
As shown in Figures 6 and 7, the improved terminal
tab illustrated in Figures 4 and 5 is atiached to -the
lower end of core 32 by percussion welding, after which
tab member 24 is bent back along base portion 18 into
contact with protrusion 46, around the edge or corner of
core 32 and into contact with the side wall of core 32.
If desired, two of such terminal -tabs may be attached to
one or both ends of the core. Preferahly, tab member
24 is posi~ioned so that it contacts the side wall of core
32 at the overlap region 48 when the negative plate extends
beyond the positive plate to contact the previous turn of
negative plate. Thus, should any compression of the
circumferential edge of core 32 occur, it will cause a
portion of the negative pla-te to contact another portion of
the negative plate and will not result in short circui-ting.
Preferahly, the outer edge 50 of the terminal tab is
positioned with a radial clearance r from the circumference
of core 32, this clearance being on more than approximately
5% of the diameter of core 32.
When the spiral wound core illustrated in Figures 6 and
7 is inserted into a battery container as shown in Figure 8,
tab member 24 is captured between container 38 and the side
wall of core 32, as illustrated~ Movement of the core into
container 38 tends to pull tab member 24 into contact with
the circumferential edge or corner of core 32; however,
the presence of protrusion 46 on the terminal tab minimizes
compression by tab member 24 of the circumferential edge
3~ of the core.
