Casting grids

Grid casting. Lead alloys are used for casting the positive and negative grids, as well as for small structural components (e.g., post straps, coimectors, terminal posts). Highly automated and efficient casting machines are used. 

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

The use of grids cast from the above multi-component alloys did reduce the need for battery maintenance but did not eliminate it altogether. So the battery industry chose two basic approaches to achieve the goal set by the automobile industry, i.e., to devise maintenance-free... 

The above results indicate clearly that, through the introduction of small amounts of alloying additives (Sn, As, Se, Cu and S) and a simple thermal treatment, grids cast from Pb—1.5 wt% Sb alloy may acquire a hardness level that meets fully the requirements of the battery industry. 

In an attempt to improve the properties of Pb—low Sb—Sn alloys and increase the productivity of the grid-casting process, different additives to these alloys have been tested. Selenium has proved to be one of the most efficient additives. Alloys with the composition Pb—3.0 wt% Sb—1.3 (or 1.5) wt% Sn—0.05 wt% Se have been in British Naval and British Rail use for over 20 years with very good results [29]. 

Effect of aluminium on the loss of calcium in grid casting [36]. 

Besides the requirements for adequate electrical, mechanical and corrosion properties of the grids, the grid pattern should allow easy casting with no defects. The process of double-grid casting provides high productivity and has therefore been widely adopted in the battery industry. 

Cathodic thermopassivation vs. number of charge/discharge cycles. Grids cast from Pb—6 wt%... 

Positive grid corrosion can be caused by the grid alloy, grid casting conditions, and active material composition. Shedding of positive active material can be caused by battery construction, active material structure, battery cycles, DOD, and charge... 

Initially most lead antimony grids were produced from a eutectic alloy of 11% antimony, which has a single freezing point at 273°C, making grid casting relatively simple. Antimony as an alloying elanent was very expensive and battery... 

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