Grid/spine casting

In Europe, and less commonly in the United States, many of the heavy-duty battery positive plates are made in porous tubular sheaths. The grid is cast or injection-molded of lead, with long-flnned spines attached to a header bar and a connection lug. Individual woven fiberglass plastic sheaths or a multitube gauntlet are placed on the spines. These plates are filled wifh powder or with a slurried paste until the tubes are full. A plastic cap plugs the open sheath ends and becomes the bottom of the plate (Fig. 23.15). 

Spine and grid casting. This process is carried out by automatic casting machines. The spines are cast under high pressure. 

This effect of antimony sustains the use of Ph—(5—10) wt% Sb alloys for casting grids and spines for the positive plates of traction batteries intended for deep discharge cycling duties. The performance characteristics of such batteries are more stable despite the higher water loss and hence the need for maintenance. 

The German company HADI Maschinenbau GmbH has developed high pressure-casting machines for casting spine grids from Pb—1.8 wt% Sb alloys. These grids have reduced substantially the need for maintenance of both traction and stationary batteries. 

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