Abstract: A glass fiber separator material is disclosed. The separator is composed of a mass of intermeshed glass fibers substantially all of which have a fiber diameter not greater than about 20 &mgr;m, and at least 5 percent w/w of which have a fiber diameter less than 1 &mgr;m, and, distributed through the glass fibers, and from 0.2 percent w/w to 20 percent w/w of cellulose fibrils. The fibrils are from a slurry having a Canadian freeness sufficiently low that the separator material has a tensile strength greater than an otherwise identical separator where glass fibers having an average diameter greater than 1 &mgr;m replace the cellulose fibrils.

Abstract: A multi-layer sheet useful as a separator (10) in a lead acid battery is disclosed. The sheet comprises at least a first layer (12) and a second layer (14) and having been produced by the method consisting of the steps of forming the first layer (12) by depositing a first, substantially binder free furnish consisting essentially of glass fibers onto the wire (36) of a paper making machine (30) and forming the second layer (14) by depositing a second, substantially binder free furnish consisting essentially of glass fibers and silica powder or another suitable silicate powder onto the first layer (12) on the wire (36) of the paper making machine (30). The silica or silicate powder has a particle size and being present in the second layer (14) in an amount such that, if the second substantially binder free furnish was deposited directly on the wire (36) of the paper making machine (30) a significant portion of the silica or silicate powder would pass through the wire (36).

Abstract: A substantially binder-free glass fiber separator, especially for valve regulated ("sealed") lead acid batteries is disclosed. The separator has a reduced thickness and temporarily inhibited resiliency. A substantially binder-free glass fiber web having a given thickness is wetted with a controlled amount of liquid and compressed to a substantially reduced thickness and the liquid suppresses the natural resiliency of the glass fiber separator so that it will have a substantially reduced thickness when the compression is released. The amount of liquid required to suppress the resiliency of the glass fiber separator is substantially less than the minimum amount of the portion of electrolyte which would be carried in the separator in a finished cell.

Abstract: A substantially binder-free glass fiber separator, especially for valve regulated ("sealed") lead acid batteries is disclosed. The separator has a reduced thickness and temporarily inhibited resiliency. A substantially binder-free glass fiber web having a given thickness is wetted with a controlled amount of liquid and compressed to a substantially reduced thickness and the liquid suppresses the natural resiliency of the glass fiber separator so that it will have a substantially reduced thickness when the compression is released. The amount of liquid required to suppress the resiliency of the glass fiber separator is substantially less than the minimum amount of the portion of electrolyte which would be carried in the separator in a finished cell.