US 12,148,952 B2
Multilayer separator including polyolefin based substrate layer stacked with polyolefin resin layer and cellulose fibers based outer layer, and lithium ion battery including the same
Oussama El Baradai, Basel (CH); and Pascal Haering, Muttenz (CH)
Assigned to RENATA AG, Itingen (CH)
Filed by Renata AG, Itingen (CH)
Filed on Nov. 8, 2021, as Appl. No. 17/521,168.
Claims priority of application No. 20217473 (EP), filed on Dec. 29, 2020.
Prior Publication US 2022/0209363 A1, Jun. 30, 2022
Int. Cl. H01M 50/457 (2021.01); H01M 10/0525 (2010.01); H01M 50/403 (2021.01); H01M 50/417 (2021.01); H01M 50/429 (2021.01); H01M 50/44 (2021.01)
CPC H01M 50/457 (2021.01) [H01M 10/0525 (2013.01); H01M 50/403 (2021.01); H01M 50/417 (2021.01); H01M 50/4295 (2021.01); H01M 50/44 (2021.01)] 16 Claims
OG exemplary drawing
 
1. A multilayer separator (200) for a lithium-ion battery having a structure comprising at least:
a polyolefin based substrate layer (204) forming an inner layer of the multilayer separator (200);
a first resin layer (203) stacked on a first surface of the polyolefin based substrate layer (204) and a second resin layer (203) stacked on a second surface of the polyolefin based substrate layer (204), the resin layer (203) being formed from a polyolefin;
a first cellulose fibers based outer layer (202) stacked on a surface of the first resin layer (203), and a second cellulose fibers based outer layer (202) stacked on a surface of the second resin layer (203),
wherein said polyolefin based substrate layer (204) comprises polypropylene or a blend comprising polypropylene and polyethylene,
wherein the first polyolefin based resin layer (203) and the second polyolefin based resin layer (203) comprise at least one selected from the group consisting of polyethylene, and a blend comprising polypropylene and polyethylene,
wherein the first cellulose fibers based outer layer (202) and the second cellulose fibers based outer layer (202) comprise at least one selected from the group consisting of ethyl cellulose, methyl cellulose, hydroxypropyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl methyl cellulose, carboxymethyl cellulose, cellulose acetate, cellulose triacetate, cellulose acetate phthalate, nitrocellulose, cellulose acetate butylate, cellulose acetate propionate, ammonium thereof, and salt thereof,
wherein said polyolefin based substrate layer (204) comprises a random copolymer of ethylene and alpha-olefins selected from the group consisting of alpha-olefins having a polymerized alpha olefin content about 20% by weight,
wherein the polyolefin based substrate layer (204) has a melting point of 80 to 124° C. and each of the first resin layer (203) and the second resin layer (203) has a melting point of 130 to 160° C., and
wherein the polyolefin based substrate layer (204) has a thickness of 5 to 15 μm, each of the first resin layer (203) and the second resin layer (203) has a thickness of 12 to 75 μm and the cellulose fibers based outer layer (202) has a thickness of 1 to 5 μm.