Chinaplas 2013: Bi-oriented films enter lithium ion battery field; low cost promised

Increasing demand for lithium ion batteries (LiB) coupled with pressures to reduce battery cost could open up a significant new market for biaxially oriented (BO) films based on a new low-cost process. Germany's Brückner (Siegsdorf) says it has developed technology for BO-polyethylene (PE)-based battery separator film (BSF) that is up to around 75% more cost-effective compared with existing processes. Three machines employing the new process are already on order for delivery in 2014.

Brückner's Evapore BOPE process for BSF entails extrusion of a film containing a "plasticizer" that evaporates out of the extruded film without the need for heating to form the porous structure required. The BSF thus produced is 14-25 µm thick with a porosity of 35-55% and a pore size of <80 nm.

Target production cost for the Evapore process is $0.30-0.40 per square meter versus around $1 for existing dry processes and $1.40 for current wet process processes. Brückner is initially targeting the 3C market (communication, computer, consumer) with BOPE film manufactured using its "semi-wet" process....

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