Hanwha Total said Monday it has increased its annual plastic production capacity to 140,000 metric tons as demand has spiked for plastic, the raw material for separators, one of the key components of lithium-ion batteries along with cathodes, anodes and electrolytes.

The expansion, which cost 40 billion won ($36.9 million), will allow the South Korean petrochemical company to produce 140,000 tons of ultrahigh-molecular-weight polyethylene (UHMWPE) at its plant in Daesan, South Chungcheong Province.

As the name suggests, UHMWPE is characterized by an extremely high molecular density and long molecular chains. Such properties offer a much greater tensile strength than typical polyethylene, making the UHMWPE a suitable raw materials for separators inside electric vehicle batteries.

Separators are basically thin elastic walls with tiny holes that divide cathodes from anodes. When batteries are charged and discharged, ions go back and forth between cathodes and anodes through these tiny holes. Separators prevent cathodes and anodes from reacting to each other and triggering short circuits or fires. In short, separators are what prevent batteries from exploding.

The UHMWPE has recently gained attention as demand for thinner but stronger separators has increased significantly, according to the company. The thinner the separators, the thicker the cathodes and anodes can become, increasing the energy capacity of batteries, which translates to a greater driving range for EVs.

By Kim Byung-wook (kbw@heraldcorp.com)