Separator (electricity)

A separator in electrochemical elements such as the electrolytic and the galvanic cells has physically and electrically disconnect the object, a cathode and anode, i.e., the negative and positive electrodes in the accumulator cells, and primary cells. However, the separator must be permeable to which effect the conversion of the stored chemical energy into electrical energy for the ions. The materials are mainly microporous plastics and nonwovens made ​​of fiberglass or polyethylene used.

Task and structure

The separator has the function of a barrier, the two electrodes electrically insulated from each other to prevent internal short circuits. At the same time, however, the separator must be permeable to ions, so that the electrochemical reactions can take place in the cell.

A separator must be thin so that the internal resistance is very low and a high packing density can be achieved. Only such a good performance and high capacity are possible. Other important functions of the separator is to absorb the electrolyte and to ensure the gas exchange in the closed cells. While in the past, inter alia, fabric and paper were used are mostly very fine-pored materials in use, such as non-woven fabrics and membranes nowadays.

As the separator can be used in injection molded plastic webs also a simple design, if the only concern is to keep the electrodes at a certain distance.

A special form of the separator is the tube pocket. It is made of two layers of woven or non-woven fabric, the first impregnated with a resin, then sewn together and brought into a particular tube shape. These tubes are filled with active material and then used in lead-acid batteries as electrodes.

For different systems, different chemical separators must be used. Their composition depends on the electrolyte, they are exposed to during the course of the lifespan. Another criterion for the Separatorauswahl is the price. Separators which need to be stable over many charge - discharge cycles or a number of years and are manufactured from higher quality materials than those which are used in short-lived primary cells.

Separators for rechargeable or secondary elements

Separators for non-rechargeable or primary cells

Other possible applications

Batteries are exposed to high temperatures, requiring temperature-resistant materials such as heat-resistant polymers, or in some cases asbestos.

For separators in fuel cells see there.