Sep 2018, Mitsubishi Paper Mills Ltd released announcement, the company and Beijing National Energy Battery Technology Co. Ltd. reached technical cooperation agreement on NanoBaseX non-woven lithium-ion battery separators.
Information shows that, NanoBase X non-woven separator has many types, among, OZ-GX series, which uses non-woven and ceramic particles, separator thickness is 25μm, and can endure 470℃ high temperature.
ASIACHEM <China LIB Separator Annual Report 2018> research indicates that, non-woven material separator substrate materials normally use PET, fibrin, PI, PA, aramid fiber (PPTA) and polyurethane fiber etc. Non-woven material separators have advantages of thermo stability and high porosity etc. Besides, due to 3D pore structure of non-woven material, which can effectively avoid short circuit phenomenon caused by needling, and increase liquid retention rate. These characteristics of non-woven separators especially suit for applying to power LIB.
Yet, currently, non-woven material LIB separator application in power batteries still is still under pilot test production and small-scale trial production stage, which mainly because:
1) Non-woven material separator tensile strength is low (<80MPa), which caused it is hard to apply on high speed winding process, but only lamination process.
2) Non-woven material separator pore diameter is large (>100nm), quite large pore diameter brings quite good battery rate performance. However, it will also lead to quite large battery self discharge, high temperature and storage performance need to be further authentication.
3) Needs to change a lot current LIB production technology. No matter separator cutting, baking temperature or liquid injection volume, non-woven separator and LIB separator have quite large differences. Generally speaking, non-woven material separator water content is quite high, to some extents, it will influence battery performance, and even cause higher battery short circuit rate.
4) Currently, non-woven material separator price is much higher than polyolefin material separator.
ASIACHEM <China LIB Separator Annual Report 2018> information shows that, since 2010, the US DuPont announced that it has developed PI separator, global and China non-woven separator R&D and market progresses are as table shown below.
