Alloy for battery grids

Abstract

A grid for a battery having a current collection lug and a plurality of wires is made by a method that includes forming the grid utilizing a punching operation. The grid is formed of an alloy including calcium in an amount of about 0.05 percent by weight to about 0.08 percent by weight, tin in an amount of about 1.2 percent by weight to about 1.8 percent by weight, and bismuth in an amount of less than about 0.04 percent by weight. The balance of the alloy comprises lead.

What is claimed is:  
     
         1 . A grid for a battery having a current collection lug and a plurality of wires, the grid made by a method comprising: 
 forming the grid utilizing a punching operation;    wherein the grid is formed of an alloy comprising: 
 calcium in an amount of about 0.05 percent by weight to about 0.08 percent by weight;  
 tin in an amount of about 1.2 percent by weight to about 1.8 percent by weight; and  
 bismuth in an amount of less than about 0.04 percent by weight;  
 wherein the balance of the alloy comprises lead;  
   whereby the bismuth is provided in an amount sufficient to enhance the hardness stability of the alloy.    
     
     
         2 . The grid of  claim 1  wherein the calcium is in an amount of about 0.05 percent by weight to about 0.0725 percent by weight.  
     
     
         3 . The grid of  claim 1  wherein the calcium is in an amount of about 0.055 percent by weight to about 0.07 percent by weight.  
     
     
         4 . The grid of  claim 3  wherein the calcium is in an amount of about 0.06 percent by weight to about 0.07 percent by weight.  
     
     
         5 . The grid of  claim 1  wherein the tin is in an amount of about 1.2 percent by weight to about 1.65 percent by weight.  
     
     
         6 . The grid of  claim 1  wherein the ratio of the calcium to the tin is greater than about 12 to 1.  
     
     
         7 . The grid of  claim 1  wherein the alloy further comprises silver as an impurity element.  
     
     
         8 . The grid of  claim 1  wherein the alloy further comprises silver in an amount of about 0.0005 percent by weight to about 0.02 percent by weight.  
     
     
         9 . The grid of  claim 1  wherein the alloy further comprises silver in an amount of about 0.001 percent by weight to about 0.005 percent by weight.  
     
     
         10 . The grid of  claim 1  wherein the bismuth is in an amount of about 0.0005 percent by weight to about 0.0225 percent by weight.  
     
     
         11 . The grid of  claim 10  wherein the bismuth is in an amount of about 0.001 percent by weight to about 0.0190 percent by weight.  
     
     
         12 . The grid of  claim 11  wherein the bismuth is in an amount of greater than about 0.0115 percent by weight.  
     
     
         13 . The grid of  claim 1  wherein the bismuth is in an amount of about 0.0115 percent by weight to about 0.0165 percent by weight.  
     
     
         14 . The grid of  claim 1  further comprising forming a slab from the alloy prior to the step of forming the grid.  
     
     
         15 . The grid of  claim 14  further comprising rolling the slab to decrease its thickness before the step of forming the grid utilizing a punching operation.  
     
     
         16 . The grid of  claim 15  wherein the step of rolling the slab to decrease its thickness comprises decreasing the thickness of the slab to about 10 percent of the original thickness of the slab.  
     
     
         17 . The grid of  claim 14  wherein the step of forming the slab comprises casting the slab.  
     
     
         18 . A grid for a battery having a lug for collecting current and a plurality of wires, the grid manufactured by a method comprising: 
 providing a slab of grid alloy;    rolling the slab to decrease the thickness of the slab; and    punching the slab after the rolling step to form the grid;    wherein the grid alloy comprises: 
 calcium in an amount of about 0.05 percent by weight to about 0.08 percent by weight;  
 tin in an amount of about 1.2 percent by weight to about 1.8 percent by weight; and  
 bismuth in an amount of greater than about 0.0115 percent by weight;  
 wherein the balance of the alloy comprises lead.  
   
     
     
         19 . The grid of  claim 18  wherein the tin is in an amount less than about 1.5 percent by weight.  
     
     
         20 . The grid of  claim 18  wherein the grid alloy comprises silver in an amount of about 0.0005 percent by weight to about 0.02 percent by weight.  
     
     
         21 . The grid of  claim 18  wherein the grid alloy comprises silver in an amount of about 0.001 percent by weight to about 0.015 percent by weight.  
     
     
         22 . The grid of  claim 18  wherein the grid alloy comprises silver in an amount of about 0.001 percent by weight to about 0.005 percent by weight.  
     
     
         23 . The grid of  claim 18  wherein the grid alloy comprises silver as an impurity element.  
     
     
         24 . The grid of  claim 18  wherein the bismuth is in an amount of less than about 0.0275 percent by weight.  
     
     
         25 . The grid of  claim 21  wherein the bismuth is in an amount of less than about 0.0225 percent by weight.  
     
     
         26 . The grid of  claim 25  wherein the bismuth is in an amount of less than about 0.019 percent by weight.  
     
     
         27 . The grid of  claim 26  wherein the bismuth is in an amount of about 0.015 percent by weight to about 0.0165 percent by weight.  
     
     
         28 . The grid of  claim 18  wherein the bismuth is in an amount of less than about 0.04 percent by weight.  
     
     
         29 . The grid of  claim 18  wherein the step of providing a slab of grid alloy comprises casting the slab from the grid alloy.  
     
     
         30 . A method of producing a grid for a battery having a lug for collecting current and a plurality of wires, the method comprising: 
 providing a slab of grid alloy;    decreasing the thickness of the slab; and    punching the slab to form the grid after the step of decreasing the thickness of the slab;    wherein the grid alloy consists essentially of: 
 calcium in an amount of about 0.05 percent by weight to about 0.08 percent by weight;  
 tin in an amount of about 1.2 percent by weight to about 1.8 percent by weight; and  
 bismuth in an amount of less than about 0.04 percent by weight;  
 wherein the balance of the grid alloy comprises lead.  
   
     
     
         31 . The method of  claim 30  wherein the calcium is in an amount of about 0.055 percent by weight to about 0.07 percent by weight.  
     
     
         32 . The method of  claim 31  wherein the calcium is in an amount of about 0.06 percent by weight to about 0.07 percent by weight.  
     
     
         33 . The method of  claim 30  wherein the tin is in an amount of about 1.2 percent by weight to about 1.65 percent by weight.  
     
     
         34 . The method of  claim 30  wherein the ratio of calcium to tin is greater than about 12 to 1.  
     
     
         35 . The method of  claim 30  wherein the grid alloy includes silver as an impurity.  
     
     
         36 . The method of  claim 30  wherein the bismuth is in an amount of about 0.0005 percent by weight to about 0.0225 percent by weight.  
     
     
         37 . The method of  claim 36  wherein the bismuth is in an amount of about 0.001 percent by weight to about 0.0190 percent by weight.  
     
     
         38 . The method of  claim 30  wherein the step of forming the slab comprises casting the slab.  
     
     
         39 . The method of  claim 38  further comprising rolling the slab to decrease its thickness before the step of forming the grid utilizing a punching operation.  
     
     
         40 . The method of  claim 39  wherein the step of rolling the slab to decrease its thickness comprises decreasing the thickness of the slab to about 10 percent of the original thickness of the slab.