Grid production

The production of automotive batteries includes three techniques of grid production:
  • method of gravity casting with flame shield;
  • expansion of lead-calcium strip;
  • Punching line, new method of grid production by cold-stamping, which includes process of continuous preparation of lead alloys.
The method of gravity casting with flame shield is used for positive grids of low-antimonous alloy with increased content of tin for hybrid batteries of heavy group. The production equipment is made by Wirtz, USA.
 
The advantages of such technology are high mechanical durability of the grid, stability of the battery for deep discharges and overcharges, as well as low water consumption and self-discharge. These features are very important for batteries operating in the hard conditions of
exploitation.
 
The method of expansion of lead-calcium strip is used for production of positive and negative grids of light group as well as negative grids for heavy group batteries. Such strip comes as the result of repeated rolling on the strip line machine of Italian firm SOVEMA, which consist of:
  • two 15-ton melting tanks, one of which works as a mixer for lead alloy. The second tank is intermediary, it ensures the continuous work of the system;
  • unit for casting of the slab with asymmetric crystallization;
  • unit for delivery of liquid alloy into the casting unit;
  • rolling unit with seven rolling mills;
  • unit for trimming strap edges;
  • unit for trimming strap edges;
  • unit for winding the strap into rolls;
  • unit for delivering of rolls to the special palette for transportation.
For production of the strip the plant uses the lead-calcium alloy of its own preparation.
 
The advantages of this technology allow production of a very thin grid, and that makes possible to increase the number of plates in the battery. And the more plates in the battery - the better starting performance of the battery.
 
A new method of positive grid production, a Punching Line, is used on both production plants. Such method includes continuous preparation of lead alloy with specific chemical composition, further symmetrical crystallization of wide-strip slab. The other stages of this method include multistage deep rolling, immediate stamping of the shunt and winding of continuous grid on drums.
 
The above-mentioned method gives considerable increase in corrosion and mechanical durability and lowers the consumption of lead alloy.
 
The casting of lead-calcium strip with symmetrical crystallization and rolling, with further cold punching of shunts is made on a special automated system.