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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
First Claim
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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.

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