Backweb, Ribs, and Overall Thickness

Separator backweb refers to the porous separating membrane. It is of uniform thickness and has a macroscopically uni- 

The lead-acid battery has a peculiarity the electrolyte sulfuric acid not only serves as ion conductor (as charge-transport medium), but it actively participates in the electrochemical reaction  

During charging at the positive electrode one additional water molecule is consumed per electron converted, which is regenerated during discharging. 

Porosity of a separator is defined as the ratio of void volume to apparent geometric volume. High porosity is desirable for unhindered ionic current flow. 

The pores of the separating membrane are to be most uniformly distributed and of minimum size to avoid deposition of metallic particles and thus electronic bridging. One distinguishes between macroporous and microporous separators, the latter having to show pore diameters below 1 micron (/im), i.e., below one-thousandth of a millimeter. Thus the risk of metal particle deposition and subsequent shorting is quite low, since active materials in storage batteries usually have particle diameters of several microns. 

Separator backweb refers to the porous separating membrane. It is of uniform thickness and has a macroscopically uniform pore distribution. Only in this way can an overall uniform current density be ensured during the operation of the storage battery, achieving a uniform charging and discharging of the electrodes and thus a maximum utilization of the electrode materials. 

In practice the desired electrolyte distribution is achieved by distance-maintaining ribs on the porous backweb this in addition has the advantage of maintaining 

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