Battery separator for a storage battery

Abstract

A battery separator for a lead acid (storage) battery is made from a thermoplastic sheet material. The sheet material has a central region flanked by peripheral regions. The central region includes a plurality of longitudinally extending ribs that are integrally formed from the sheet material. The peripheral regions are free of ribs and may include a densified structure. Also disclosed are a method of producing the foregoing separator, an envelope separator made from the sheet material, and a method of making the envelope separator.

We claim: 
     
         1 . A battery separator for a lead acid battery comprising:
 a thermoplastic sheet with a planar back web and a longitudinal central region between peripheral regions;   a plurality of longitudinal main ribs on at least one side the thermoplastic sheet, the main ribs are spaced apart and integrally formed with the thermoplastic sheet; and,   a plurality of transverse ribs on at least the other side the thermoplastic sheet.   
     
     
         2 . The battery separator according to  claim 1  wherein in the central region the sheet between the main ribs has a thickness of 0.05 to 0.35 mm. 
     
     
         3 . The battery separator according to  claim 1  wherein the sheet material is formed into an envelope. 
     
     
         4 . The battery separator according to  claim 3  wherein overlapping edges of the envelope are mechanically sealed to one another. 
     
     
         5 . A lead acid battery comprising the battery separator of  claim 1 . 
     
     
         6 . A lead acid battery comprising the battery separator of  claim 3 . 
     
     
         7 . The battery separator according to  claim 1  having a plurality of transverse ribs on both sides of the thermoplastic sheet. 
     
     
         8 . The battery separator according to  claim 1  having a plurality of transverse ribs on only the other side of the thermoplastic sheet from said longitudinal main ribs. 
     
     
         9 . A battery separator for a lead acid battery comprising:
 a thermoplastic sheet with a planar back web and a longitudinal central region between peripheral regions;   a plurality of longitudinal main ribs on at least one side the thermoplastic sheet, the main ribs are spaced apart and integrally formed with the thermoplastic sheet;   a plurality of transverse ribs on at least the other side the thermoplastic sheet, the transverse ribs are integrally formed with the thermoplastic sheet.   
     
     
         10 . The battery separator according to  claim 9  wherein the plurality of transverse ribs are only on the other side of the thermoplastic sheet from the main ribs. 
     
     
         11 . The battery separator according to  claim 9  wherein the plurality of transverse ribs are on both sides of the thermoplastic sheet. 
     
     
         12 . The battery separator according to  claim 9  wherein the sheet material is formed into an envelope. 
     
     
         13 . The battery separator according to  claim 12  wherein overlapping edges of the envelope are mechanically sealed to one another. 
     
     
         14 . A lead acid battery comprising the battery separator of  claim 9 . 
     
     
         15 . A lead acid battery comprising the battery separator of  claim 12 . 
     
     
         16 . An envelope battery separator for a lead acid battery comprising:
 a thermoplastic sheet with a planar back web and a longitudinal central region between peripheral regions;   a plurality of longitudinal main ribs on at least one side the thermoplastic sheet, the main ribs are spaced apart and integrally formed with the thermoplastic sheet;   a plurality of transverse ribs on at least the other side of the thermoplastic sheet, the transverse ribs are integrally formed with the thermoplastic sheet; and,   wherein the sheet material is formed into an envelope.   
     
     
         17 . The battery separator according to  claim 16  wherein overlapping edges of the envelope are mechanically sealed to one another. 
     
     
         18 . The battery separator according to  claim 16  wherein the plurality of transverse ribs are only on the other side of the thermoplastic sheet from the main ribs. 
     
     
         19 . The battery separator according to  claim 16  wherein the plurality of transverse ribs are on both sides of the thermoplastic sheet. 
     
     
         20 . A lead acid battery comprising the battery separator of  claim 16 .