Grids manufacture

Liquid to grids is usually supplied by spray nozzles, and thess may plug. As with other distributors, adequate measures are required to prevent plugging, and the grid manufacturer must be supplied with good data on the fouling potential of the service. 

The first grid alloys used were lead alloys with 11% antimony content called hard lead . These alloys were replaced with low-antimony lead alloys with additions of Sn, As and Ag. Later, battery grid manufacturers switched to lead—calcium and lead—calcium—tin alloys. 

At the end of the century, new methods of plate grid manufacture were introduced, parallel to casting. These include the expanding metal grid process and, more recently, the die-cut technology. 

A disadvantage of these alloys is their softness. So they cannot be manufactured by the conventional casting process, because they could not be handled in the usual equipment, like pasting machines. Rather they depend on continuous processes that combine grid manufacture with pasting. 

Other continuous grid manufacturing processes. The cross section of a lead-coated copper grid is shown in Figure 6.16. 

Ease of grid manufacture Good Pair Pair Pair to good Pair Good... 

Ease of grid manufacture Eair to good Good (aluminum) Good Good Conductivity... 

Another method of grid manufacture is via mechanical treatment of a strip or slab of lead alloy. The traditional procedures (Plant6-type plate) have been either to cut grooves into a thick lead plate, thereby increasing its surface area, or to crimp and roll up lead strips into rosettes which are inserted into round holes in a cast plate. The resultant plates are formed electrolytically into positives in the classic Plante and Manchester designs (Fig. 23.13). 

Antimony was originaUy chosen as an alloying element because it imparted hardness to the grids, which allowed them to withstand the intense mechanical stresses associated with chemical reactions within the battery itself and with difficult physical conditions, including vibrations and shocks related to on-the-road use. However, since the late 1970s calcium has been increasingly used in place of antimony in lead-alloy grid manufacture, due both to its beneficial impact on battery life, and because it permits low or zero maintenance battery operation. ... 

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