Method of forming through the partition cell connectors formed by an extrusion-fusion technique

• US 4,046,062 A
• Filed: 04/15/1971
• Issued: 09/06/1977
• Est. Priority Date: 12/20/1968
• Status: Expired due to Term

• Current Assignee: General Motors Corporation (General Motors Company)
• Original Assignee: General Motors Corporation (General Motors Company)
• Inventors: Matter, Robert C.
• Primary Examiner(s): Lefevour, C. F.
• Application Number:
  US05/134,442
• Time in Patent Office: 2,336 Days
• Field of Search: 136/134, 136/79, 136/80, 136/81, 136/175, 136/176, 174/84, 219/86, 29/623.1
• US Class Current: 29/623.1
• CPC Class Codes: H01M 50/529 Intercell connections through partitions, e.g. in a battery casing
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y10T 29/49108 Electric battery cell making

Abstract

A method of forming a through-the-partition intercell connection between adjacent cell groups in a battery. Plate strap lugs are positioned on either side of an aperture in a partition between adjacent cells. The lugs are pressed tightly against the partition walls by opposing hold-down sleeves. Opposing extruder-electrodes move axially through the hold-down sleeves and extrude portions of each lug into the aperture. The aperture acts as an extrusion die. When extrusions contact one another inside the aperture, current is caused to flow through the extruder-electrode. The tips of the extrusions fuse and the balance softens. Extrusion of the soft material continues until the aperture is filled.

Claims

1. A method of making substantially liquid-tight intercell connections for lead-acid storage batteries of the type having (a) nonconductive partitions dividing the case of the battery into compartments, (b) apertures in the partitions connecting adjacent compartments, (c) cell groups in the compartments, (d) a plate connector strap on each cell group, and (e) upstanding lead or lead alloy lugs on the connector straps with the lugs facing each other on each side of the apertures, the lugs being thicker than a said partition and having face portions on their face sides adapted to fully engage the immediate surface areas of the partitions around the apertures and joint-forming portions circumscribed by said face portions and adapted by fusion to link one lug to the other through the apertures, said method comprising the steps of:

positioning the cell groups with their associated straps in the compartments so that the lugs of the straps overlay the apertures of the partitions with the face portions adjacent the immediate surface area around the apertures;

positioning tool means on the back sides of the lugs, the tool means for each lug including a clamp portion, a bore in the clamp portion and a conductive plunger movable in the bore, the bores and plungers for opposing lugs being aligned with a substantial area of their associated aperture;

actuating the tool means to cause the clamp portions to engage the lugs with a sufficient clamping force to seal off the apertures with the face portions of the lugs, the joint-forming portions being spaced from each other midway through the apertures and with the partitions defining apertures which are substantially free of lug material;

while maintaining the clamping force, squeezing the plungers with sufficient plunger pressure to cause the plungers to sink into the back sides of the lugs to a depth less than their thickness and short of the mouths of the apertures to extrude lead or lead alloy from the joint-forming portions of the lugs into the apertures to bridge the space therein and make contact between the lug extrusions approximately midway through the apertures;

while maintaining the pressure on the plungers and the force on the clamp portions, passing electrical current through the plungers and lug extrusions to fuse the lead or lead alloy in the apertures and to extrude more of the lugs into the apertures until voids therein fill completely with only fused lead or lead alloy which is forced out of the lugs, and, at the same time, seal against the leakage of fused lead or lead alloy from the apertures by the forcible engagement of the face portions of the lugs with the immediate surface areas around the apertures;

deenergizing the electrical current while continuing to maintain the clamping force and plunger pressure to keep the apertures filled during the solidification and cooling of the fused lead or lead alloy in the apertures into weld nuggets, whereby the cell groups are electrically joined by the lugs by liquid-tight, through-the-partition connections that were formed by the solidification of the weld nuggets under pressure.

2. A method of connecting battery plate units of adjacent cells through an aperture in a partition between adjacent cell chambers comprising the steps of:

assembling individual plate units for each adjacent cell and placing the units in the cell chambers of a battery case, the battery case having a partition between adjacent cells and the partition having an aperture, said plate units having projections from the battery straps thereof formed with substantially flat surfaces adapted to fit over and lie against the partition surrounding the aperture;

placing a pair of electrodes against the projections from the battery straps on each side of the partition in substantial alignment with the aperture therein;

applying sufficient force to the electrodes to cause them to move relatively toward each other to deform portions of the projections into contact with each other within the aperture;

after said contact is made applying sufficient electric current thereto to fuse the deformed portions of the projections together within the aperture, and concurrently therewith applying sufficient force to said electrodes to deform sufficiently more of the projections into the aperture to fill the aperture with projections material and maintain it under pressure therein;

clamping said flat surfaces of said projections against opposite sides of said partition sufficiently to provide a liquid seal surrounding the aperture during and following said filling; and

discontinuing said current application while maintainin said force application during cooling, whereby said fused and pressurized material is confined to said aperture during said filling and a liquidtight seal is effected both within and surrounding the aperture upon cooling and removal of the electrodes.

3. A method of making substantially liquid-tight intercell connections for lead-acid storage batteries of the type having (a) at least one nonconductive partition dividing the case of the battery into compartments, (b) an aperture in the partition connecting adjacent compartments, (c) cell groups in the compartments, (d) a plate connector strap on each cell group, and (e) upstanding lead or lead alloy lugs on the connector straps with the lugs facing each other on each side of the aperture, the lugs being thicker than a said partition and having face portions on their facing sides adapted to engage the immediate surface areas of the partitions around the apertures and joint-forming portions circumscribed by said face portions and adapted by fusion to link one lug to the other through the apertures, said method comprising the steps of:

positioning the cell groups with their associated straps in the compartments so that the straps'"'"' lugs overlay the aperture such that the face portions of the lugs are adjacent the immediate surface area around the aperture and the joint-forming portions are spaced from each other across a substantial portion of the aperture;

positioning tool means on the back sides of the lugs and in substantial axial alignment with the aperture between said lugs, said tool means including means for extruding said joint-forming portions from said lugs into the aperture therebetween prior to and during subsequent welding, and means for pressing said face portions tightly against said surface areas of the partition surrounding the aperture to seal off the aperture with said face portions during and following welding;

actuating said tool means with sufficient force to sink said extruding means into the back sides of the lugs to a depth less than their thickness and short of the mouths of the aperture to cold extrude lead or lead alloy from the joint-forming portions of the lugs into the aperture to bridge the space therein and make contact between the lug extrusions approximately midway through the aperture;

containing to apply force to said tool means while passing electrical current through the lug extrusions to fuse the lead or lead alloy in the aperture and to fill the aperture with additional lead or lead alloy further extruded from the lugs during current passage while at the same time preventing expulsion of lead or lead alloy from the aperture by said pressing means pressing the face portions of the lugs into sealing engagement with the immediate surface areas around the aperture;

deenergizing the electrical current while continuing to maintain the tool force to keep the aperture filled with lead or lead alloy, sealed therein and under pressure during solidification and cooling.

4. A method of connecting battery plate units of adjacent cells through an aperture in a partition between adjacent cell chambers comprising the steps of:

assembling individual plate units for each adjacent cell and placing the units in the cell chambers of a battery case, the battery case having a partition between adjacent cells and the partition having an aperture, said plate units having battery straps thereon and upstanding lugs on said straps, said lugs being formed with substantially flat surfaces adapted to fit over and lie against the partition surrounding the aperture;

placing a pair of electrodes against said lugs on each side of the partition in substantial alignment with the aperture therein;

applying sufficient force to the electrodes to cause them to move relatively toward each other to initially cold deform portions of the lugs into contact with each other within the aperture;

while applying sufficient electric current to fuse the deformed portions of the lugs and pressing said flat surfaces of said lugs into sealing engagement with the opposite sides of said partition surrounding the aperture, forcing said electrodes further together to join said portions and secondarily warm deform more of the lugs into the aperture sufficiently to fill the aperture with lug material under pressure; and

discontinuing said current application while maintaining said force application during cooling, whereby said fused and pressurized material is confined to said aperture during said secondary deformation and a liquid-tight seal is effected both within and surrounding the aperture upon cooling.