Battery

The process used to manufacture lead acid batteries is referred to as the “Cast On Strap” or COS process. There are many different brands of machinery for the Cast On Strap process. They are TBS, Farmer and Mac/Dynacast.

The basic principles of manufacture are the same no matter which type of cast-on-strap equipment is used. The plates are stacked manually into the envelope and group assembling machines, then the automated process begins. The plates move quickly along a conveyor as they are sorted for final alignment. Sensors will stop the process if any plates are double-stacked or misaligned.

As they move along, the plates are individually brushed clean. Then they are enveloped to the exact size to fit their particular battery case. These enveloped plates now enter a chamber where the edges are joined ultrasonically and sealed to the plates. Enveloped (positive) and un-enveloped (negative) plates are then stacked together alternately. Then they are grouped and re-stacked to align them for the next process. The lugs on each plate are mechanically aligned for proper positioning before the casting operation. Six groups of plates are "picked and placed" in the COS (cast-on-strap) jig box for casting. Each group is a cell and each cell contains 2.1 volts, which equals 12.6 volts or a "12 volt battery." The lugs are automatically aligned and simultaneously brushed with flux to prepare them for the casting process.

The lead is fed through enclosed pipes at a temperature of 450° - 550°C, and poured into the mold block which is maintained at a temperature of 150° - 200°C. A pump in the mold block fills the mold cavity with lead. The design of the mold allows excess lead to quickly drain off, leaving the desired cast level. Then special water ring circuit cools the casting and an injection system frees it from the mold. This entire procedure is monitored and controlled electronically. The strap connections will now provide a series circuit between the lead plates. The battery is then unloaded, cased, and sealed.

Lead-free alternatives are not a real consideration at this time due to cost considerations. Most of the lead-acid battery is encased in plastic and batteries are fully recyclable. Compliance with environmental regulations, therefore, is not difficult.

Fry provides the automobile industry with the 981 series, maxflow RD series and the Accusol N/H 1 fluxes. There are several variations of the 981 series to allow for climate differences which effect evaporation rates and spattering potential. 981 RBW and 981 RBWX are aqueous based version used for standard evaporation. 981 RBS and 981 RBA are solvent and alcohol based which offer faster evaporation rates. The Maxflow RD 100 and RD 200 are rosin-based fluxes which are designed for processes where the lugs will sit for an extended period of time after fluxing and before the casting process. The new Accusol N/H1 is a new “halide free” COS flux. This flux is designed for facilities wanting to eliminate halides in their processes.