Patent ID: 11929458
Assignee: LG CHEM, LTD.
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H  Y | IPC H

Claim 13:
14. A separator for an electrochemical device comprising:
a porous substrate and a coating layer formed on at least one surface of the porous substrate,
wherein the coating layer comprises a binder resin and inorganic particles at a weight ratio of 30:70-60:40;
the binder resin comprises 90 wt % or more of a vinylidene fluoride homopolymer or a copolymer of vinylidene fluoride with another copolymerizable monomer based on 100 wt % of the binder resin, and the vinylidene fluoride homopolymer or the copolymer of vinylidene fluoride with another copolymerizable monomer has a weight average molecular weight of 400,000 or less and a melting point of 140° C. or less;
the separator shows a difference in air permeation time less than 40% as determined according to Formula 1;
and the coating layer includes nodes containing the inorganic particles and the binder resin covering at least a part of surfaces of the inorganic particles, and filaments formed from the binder resin of the nodes in a thread-like shape, wherein at least one of the filaments is extended from each of the nodes, and the filaments are arranged in such a manner that they connect one of the nodes with another one of the nodes:

difference in air permeation time (%)={(air permeation time of separator−air permeation of porous substrate)/air permeation time of porous substrate}×100.  [Formula 1]