Accumulator plate sheath - made of polyester fibre mat with over sixty five per-cent porosity in bag shape

The Parent Patent No.2610116 described an electrode plate for accumulators, enclosed in a sheath, consisting of an oxygen-and acid-resistant plastic material with a porosity of at least 65% by fine perforations of up to 0.1 mm diameter. As a perforated plastic foil has not an adequate strength, it is now suggested to use a fibre mat of polyester threads which is made into a pocket by sewing or welding. The fibre mat can have a percentage of glass fibres, and holes of 0.06-0.1 mm dia. give it a minimum porosity of 70-75%. This can be made at low cost and is specially suitable for positive plates which are possibly short-circuited by anode slime.