Composite current collector and methods therefor

Abstract

Contemplated bipolar lead acid batteries include a bipole assembly with a monolithic or composite current collector that is in contact with the PAM. Especially preferred current collectors have a substrate formed from pure lead and grid formed from a lead alloy, wherein the interface between the grid and substrate is formed via electroforming and/or resistance welding. Particularly preferred batteries are configured as deep cycle batteries and have a low ratio between the surface area of the grid and the weight of the PAM.

1 . A bipole assembly for use in a bipolar lead acid battery, comprising:
 a welded or monolithic composite current collector that comprises a conductive substrate formed from a first metal composition and an electroformed grid structure;   wherein the electroformed grid structure is conductively coupled to a first side of the substrate and formed from a second metal composition, and wherein the first and second metal composition are not the same.   
     
     
         2 . The bipole assembly of  claim 1  wherein the first metal composition is pure lead and wherein the second metal composition is a lead alloy. 
     
     
         3 . The bipole assembly of  claim 2  wherein the lead alloy comprises an alkaline earth metal, an alkaline metal, or tin. 
     
     
         4 . The bipole assembly of  claim 1  further comprising a non-conductive grid coupled to the substrate on a second side of the substrate that is opposite the first side, and further comprising a negative active material (NAM) contacting the non-conductive grid and the second side of the substrate. 
     
     
         5 . The bipole assembly of  claim 4  wherein the negative active material (NAM) is in-tank formed negative active material (NAM). 
     
     
         6 . The bipole assembly of  claim 1  further comprising a positive active material (PAM) contacting the electroformed or resistance welded grid structure and the first side of the substrate. 
     
     
         7 . The bipole assembly of  claim 6  wherein the positive active material (PAM) is in-tank formed positive active material (PAM). 
     
     
         8 . The bipole assembly of  claim 7  wherein the grid structure has a surface area S grid  and wherein the PAM has a weight W PAM , and wherein the ratio of W PAM  to S grid  is between 0.65-1.1 g/cm 2 . 
     
     
         9 . The bipole assembly of  claim 7  wherein the grid structure has a surface area S grid  and wherein the PAM has a weight W PAM , and wherein the ratio of W PAM  to S grid  is between 0.8-1.0 g/cm 2 . 
     
     
         10 . The bipole assembly of  claim 1  wherein the substrate is configured as a composite substrate in which a non-conductive polymer carrier is coupled to the substrate opposite the first side, wherein the polymer carrier has a plurality of openings that allow formation of a conductive path between the substrate and another conductive material located on an opposite side of the carrier. 
     
     
         11 . A bipolar lead acid battery comprising the bipole assembly of  claim 1 . 
     
     
         12 . The bipolar lead acid battery of  claim 11  wherein the battery is configured as a valve regulated lead acid battery. 
     
     
         13 . The bipolar lead acid battery of  claim 11  wherein the battery is configured as a deep cycle battery. 
     
     
         14 . A method of forming a bipole assembly for a bipolar lead acid battery, comprising a step of resistance welding a lead alloy grid structure onto a lead substrate, or gradually building a lead alloy grid structure onto a lead substrate, or gradually forming a lead substrate onto a lead alloy grid structure to thereby form a composite or monolithic current collector structure. 
     
     
         15 . The method of  claim 14  wherein the step of gradually building is selected from the group consisting of electroforming, electroplating, vapor depositing, redox depositing. 
     
     
         16 . The method of  claim 14  wherein the lead alloy comprises an alkaline earth metal, an alkaline metal, or tin. 
     
     
         17 . The method of  claim 14  further comprising a step of coupling to the lead alloy grid structure and the first side of the substrate a positive active material (PAM). 
     
     
         18 . The method of  claim 16  wherein the lead alloy grid structure has a surface area S grid  and wherein the PAM has a weight W PAM , and wherein the ratio of W PAM  to S grid  is between 0.65-1.1 g/cm 2 . 
     
     
         19 . The method of  claim 16  wherein the lead alloy grid structure has a surface area S grid  and wherein the PAM has a weight W PAM , and wherein the ratio of W PAM  to S grid  is between 0.8-1.0 g/cm 2 . 
     
     
         20 . The method of  claim 14  further comprising a step of coupling a non-conductive grid to the lead substrate on a side of the substrate that is opposite the side onto which the grid structure is formed, and further in-tank forming a negative active material (NAM) onto the non-conductive grid and the opposite side. 
     
     
         21 . The method of  claim 14  wherein the lead substrate is configured as a composite substrate in which a non-conductive polymer carrier is coupled to the lead substrate opposite the side onto which the grid structure is formed, wherein the polymer carrier has a plurality of openings that allow formation of a conductive path between the lead substrate and another conductive material located on the opposite side of the carrier.