Welding intercell connections by induction heating

In a storage battery having a plurality of electrically insulating vertical partitions, the method of the invention comprises sandwiching each partition, successively, between a pair of terminals of lead or other easily fusible material of the so-called "tombstone" type, that is, of "L" shape in which the vertical or riser portion of one terminal has a horizontal pin which extends through a hole in the partition and through a hole in the riser portion of the other terminal. An insulating sheet and induction coil are placed against the end of the pin by a fusing apparatus which is provided with a pair of arms which are pivotally operated by a fluid cylinder, one arm carrying the above-mentioned coil and insulating sheet and the other acting as a pusher. The terminal pairs and partition are squeezed together by said arms and thereafter induction current is applied to the coil to fuse the perimetrical portion of the pin and surrounding surface of the hole of the other terminal so as to fill the void therebetween and form a solid intercell connection.

This invention relates to an apparatus and method for intercell fusion of 
lead/acid storage batteries and, more particularly, to 
"through-the-partition" type intercell construction, with "pin and ring" 
style lead intercell connectors. 
BACKGROUND OF THE INVENTION 
1. Prior Art 
In one method, known as "over-the-partition hand burning" (riser 
construction), vertical lead risers from cell elements which sandwich an 
intervening rubber or plastic partition are melted over the partition and 
fused manually, using a gas torch. A metal or ceramic mold is used to 
contain the molten lead. The fused, cooled lead forms the intercell 
connection. 
In another method, known as "through-the-partition hand burning", (pin and 
ring construction), a lead pin extends horizontally from the lead 
tombstone of the positive strap of one cell element, through a round 
orifice in the intervening rubber or plastic partition, and into a 
horizontal round orifice (ring) in the lead tombstone of the negative 
strap of the element in the adjacent cell. The positive pin and negative 
ring are melted and fused manually, using a gas torch. A metal or ceramic 
mold is used to contain the molten lead. The fused, cooled lead forms the 
intercell connection. 
In still another method, known as "intercell resistance welding" (flat 
tombstone construction), vertical flat lead tombstones from the straps of 
elements in adjacent cells are positioned over a round orifice in the 
intervening rubber or plastic partition. Electrodes deform the tombstones 
until they make contact within the orifice in the partition. Current is 
then applied across the two tombstones; internal and contact resistance 
creates heat to melt and fuse the tombstones within the orifice in the 
partition. The fused, cooled lead forms the intercell connection. 
In still another method, known as "over-the-partition induction heated 
intercell fusion" (riser construction), vertical lead risers from cell 
elements adjacent to an intervening rubber or plastic partition are melted 
and fused using induction heat. A mold is used to contain the molted lead. 
The fused, cooled lead forms the intercell connection. 
2. Outstanding Disadvantages of the Prior Art 
Over-the-partition hand burning, and through-the-partition hand burning, 
are manual operations, thus they are relatively slow and yield intercell 
connections of inconsistent and unreliable quality. 
Intercell resistance welding has been automated and is relatively fast, but 
it produces intercell connections of inconsistent and unreliable quality. 
Over-the-partition hand burning and over-the-partition induction heated 
intercell fusion, share the disadvantage of the epoxy-sealed covering 
method used. This covering process has proven difficult to control and 
auotomate. 
3. Preceding Patents Noted 
The subject process, through-the-partition pin and ring induction heated 
intercell fusion differs markedly from previously patented processes as 
described below. 
U.S. Pat. No. 3,544,754, granted Dec. 1, 1970, to Buttke et al. and related 
patents refer to a method and apparatus for fusing lead/acid battery 
intercell terminals using "extrusion fusion" and resistance welding. Vital 
to this proces is the principle of extruding lead through an orifice in 
the battery container partition. Since, in the process of the present 
invention detailed here, no external pressure is supplied to extrude the 
lead, and since induction heating (not resistance welding) is utilized, 
U.S. Pat. No. 3,544,754 does not apply. 
U.S. Pat. No. 3,589,948, granted June 29, 1971 to Adams refers to various 
techniques, including induction heating, used to fuse intercell 
connections (with flat tombstones) through an orifice in battery container 
partitions. This patent specifies the use of a "mold" to "contain" the 
molten lead. Since the process of the present invention detailed here uses 
lead intercell terminals molded into male and female configuration (not 
flat), and since molds are not used to contain the molten lead, U.S. Pat. 
No. 3,589,948 does not apply. 
U.S. Pat. No. 4,501,943, granted Feb. 1985, to Lund, and U.S. Pat. No. 
4,523,068, granted June 11, 1985 to Lund, et al., refer to a method and 
apparatus for fusing external battery top terminal posts. These patents 
specify the use of a "concentric mold" to contain the molten lead. Since 
the process of the present invention detailed here refers to fusion of 
intercell connectors inside the battery, not external top terminal posts, 
and because molds are not used to contain the molten lead, U.S. Pat. Nos. 
4,501,943 and 4,523,068 do not apply. 
U.S. Pat. No. 3,336,164, granted Aug. 15, 1967 to Miller, and related 
patents, refer to method and apparatus for fusing internal intercell 
connections with pin and ring construction using manual gas torch 
"burning". Since the present invention detailed here, 
through-the-partition pin and ring induction heated intercell fusion, 
employs induction heating (not manual gas torch "burning"), U.S. Pat. No. 
3,336,164 does not apply. 
SUMMARY OF THE INVENTION 
An object of the invention is to overcome the above-named disadvantages by 
providing induction heat to be used to produce intercell connections of 
uniformly high quality in lead/acid storage batteries with 
"through-the-partition" type construction using "pin and ring" lead 
intercell connectors. 
Another object of the present invention is to automatically, rapidly and 
reliably fuse the series electrical connections between adjacent cell 
elements in a lead/acid storage battery, constructed with "pin and ring" 
"through-the-partition" type intercell connections to achieve high 
production rates of 3 to 4 batteries per minute--or, in smaller 
semi-automatic devices 1 to 2 batteries per minute.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring more particularly to FIG. 1, it shows a fusion device comprising 
flat terminals 1 and 2 of copper or other suitable electrical conducting 
material, having sandwiched therebetween an electrical insulator 3. This 
assembly is clamped together by a plurality of bolts 4, electrically 
insulated from the terminals by insulator rings 5. Metal tubes 6, one on 
each side of the fusion device, which are of copper or other electrical 
conducting material, are connected at their lower ends, by clamps 6a or 
hoses 7,7 which are, in turn, connected to electrical conducting tubes 8,8 
whose lower terminals are integrally connected to the ends of a tubular 
induction coil 9 of electrical conducting material, such as copper. The 
coil 9 preferably has two or more turns which are fitted into a 
correspondingly shaped opening in refractory insulator 10, shown in an 
exploded view for clarity of illustration. 
In assembly, the sides of insulator 10 are slid into flanged supports 11,11 
and bolts 12,12 are inserted through holes 11a and thereafter tightened so 
that coil 9 will be supported directly opposite a metal plate 18 having a 
bulged portion 19, both of which are supported opposite the lower end of a 
lever 17,17 pivotally mounted on the pivot 18. A mica strip 13 is provided 
on one side of insulator 10. 
Flange 20,20 has an insulator 21 therebetween which is bolted by means of 
bolts 22 to the pivot block 21. Likewise, flanges 24,24 are separated by 
insulator 25 for insulating the supporting arm 26 to which one end of a 
fluid cylinder 27 is connected. The other end of this cylinder is 
connected pivotally by a pin 28 to lever 17,17. 
In operation, in response to the well-known sliding operation of the piston 
(not shown) in cylinder 27, by selective introduction of a suitable fluid, 
such as air or liquid, or either one side or an opposite side of the 
piston, the lever 17,17 can move either counterclockwise or clockwise so 
as to selectively push the plate 18 and bulge 19 either towards or away 
from coil 9. 
It will be understood that a suitable liquid, such as water, will flow 
through the tubular conduits 6, 7, 8 and 9 to cool coil 9. 
Such coil 9 is energized by high frequency alternating current to provide 
induction heating to any inductive object(s) between it and the plate 18. 
The device shown in FIG. 1 may be used to fuse intercell connections such 
as described hereinafter. 
FIG. 2 and FIG 3 show a pair of tombstones 30,31 having straps 30a and 31a, 
respectively, which are of lead or other suitable material, which can be 
melted under relatively low heat. Partition 32, of polypropylene or other 
suitable electrically insulating material, is provided with a hole 32a 
through which extends the male portion (pin) 31b of tombstone 31. Said 
male pin 31b also extends through the female ring 30b in the adjacent 
tombstone 30. 
More specifically, an induction coil 9, such as shown in FIG. 1, may be 
applied alongside one of the tombstones, such as 30, preferably concentric 
with the pin 31b and ring 30b, so as to provide a heat zone at the 
external surface portions of the pin 31b and ring 30b. The device shown in 
FIG. 1 may be applied so as to tightly hold together tombstones 30,31 and 
apply induction heat through coil 9. This will avoid the necessity of 
using a surrounding mold since the unmelted sides of the tombstones 30,31 
and mica strip 13 dam the molten lead. 
In operation, after the A.C. induction current, of the order of 450 KHZ 
(K-hertz), or other value, is applied to coil turns 9, and at the same 
time as the tombstones and mica strip 13 are being squeezed by two arms of 
the welder, then, upon application of induction A.C. current, lead of the 
tombstones will melt in the vicinity of the external surface portions of 
the pin 31b and ring 30b. After fusing and cooling, this melt of pin 31b 
and ring 30b forms a rugged, high quality intercell connection. 
Thus it will be seen that we have provided an efficient, rapid, quick and 
consistently reliable method and apparatus for joining together pin and 
ring style lead intercell connectors by "through-the partition" 
inter-connection which lends itself to mass production methods. 
While we have illustrated and described a single specific embodiment of our 
invention, it will be understood that this is by way of illustration only 
and that various changes and modifications may be contemplated in our 
invention within the scope of the following claims.