CN-122000616-A - Separator for rechargeable lithium battery and rechargeable lithium battery including the same

Abstract

A separator for a rechargeable lithium battery and a rechargeable lithium battery including the same are provided. The separator comprises one or more fibrous layers, wherein at least one of the fibrous layers comprises a fibrous network of fibers comprising a first copolymer, or at least one of the fibrous layers comprises a network of core-shell fibers comprising a first copolymer. The first copolymer includes a copolymer of a monomer mixture including a first structural unit including a unit derived from an aromatic-based unsaturated monomer, a second structural unit derived from a (meth) acrylic monomer including an alkyl group having 4 or more carbon atoms in the main chain in an ester moiety, and a third structural unit derived from a monomer including a sulfonic acid group.

Inventors

• JU ZIYAN
• XU DONGWAN
• Jin Jiaren
• Pu Enzhen
• An Huican

Assignees

• 三星SDI株式会社

Dates

Publication Date

20260508

Application Date

20251107

Priority Date

20241107

Claims (19)

1. 1. A separator for a rechargeable lithium battery, the separator comprising: one or more of the fiber layers, Wherein at least one of the one or more fibrous layers comprises a fibrous network of fibers comprising a first copolymer, or At least one of the one or more fiber layers comprises a network of core-shell fibers comprising a first copolymer, The first copolymer includes a copolymer of a monomer mixture including a first structural unit including a unit derived from an aromatic-based unsaturated monomer, a second structural unit derived from a (meth) acrylic monomer including an alkyl group having 4 or more carbon atoms in the main chain in an ester moiety, and a third structural unit derived from a monomer including a sulfonic acid group, and The first structural unit, the second structural unit, and the third structural unit are included in a range of 5mol% to 80mol%, a range of 10mol% to 60mol%, and a range of 5mol% to 80mol%, respectively, with respect to 100mol% of the copolymer.
2. 2. The separator of claim 1, wherein the first copolymer comprises a binder.
3. 3. The separator of claim 1, wherein the first copolymer has a glass transition temperature in the range of 60 ℃ to 80 ℃.
4. 4. The separator according to claim 1, wherein a sum of contents of the first structural unit, the second structural unit, and the third structural unit in the copolymer is 95mol% or more.
5. 5. The separator according to claim 1, wherein the unit derived from the aromatic-based unsaturated monomer is represented by chemical formula 1, Chemical formula 1: ; In the chemical formula 1, the chemical formula is shown in the drawing, R 1 and R 2 each independently comprise hydrogen or a substituted or unsubstituted C1 to C5 alkyl group, and Ar comprises a substituted or unsubstituted monocyclic or polycyclic C6 to C20 aryl group, The second structural unit is represented by chemical formula 4, Chemical formula 4: ; in the chemical formula 4, the chemical formula is shown in the drawing, R 7 and R 8 each independently comprise hydrogen or methyl, L 2 comprises a substituted or unsubstituted, linear or branched, C4 to C30 alkyl group, and The third structural unit is represented by any one of chemical formula 5, chemical formula 6, and chemical formula 7: Chemical formula 5: ; chemical formula 6: ; Chemical formula 7: ; in the chemical formulas 5 to 7, R 9 、R 10 、R 11 、R 12 、R 13 and R 14 each independently comprise hydrogen or C1 to C3 alkyl, Each of L 3 、L 5 and L 7 independently includes-C (=o) -, -C (=o) O-, -OC (=o) -, -O-, or-C (=o) NH-, L 4 、L 6 and L 8 each independently comprise a substituted or unsubstituted C1 to C10 alkylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, a substituted or unsubstituted C6 to C20 arylene group, or a substituted or unsubstituted C3 to C20 heterocyclyl group, and A. b, c, d, e and f are each independently integers in the range of 0 to 2, and In the chemical formula 6, the chemical formula is shown in the drawing, M comprises an alkali metal.
6. 6. The separator of claim 1, wherein the first structural unit further comprises a unit derived from a (meth) acrylic monomer comprising an alkyl group having 1 to 3 carbon atoms in the backbone in an ester moiety.
7. 7. The separator according to claim 6, wherein the unit derived from the (meth) acrylic monomer is a unit represented by chemical formula 3: Chemical formula 3: ; In the chemical formula 3, the chemical formula is shown in the drawing, R 5 and R 6 each independently comprise hydrogen or methyl, L 1 comprises a substituted or unsubstituted, linear or branched C1 to C3 alkyl group.
8. 8. The separator of claim 1, wherein the separator comprises a multi-layer separator comprising the one or more fibrous layers.
9. 9. The separator of claim 8, wherein the multilayer separator comprises one or more fibrous layers or two or more fibrous layers, a fibrous layer comprising a fibrous network comprising fibers of the first copolymer.
10. 10. The separator of claim 9, wherein the multilayer separator further comprises one or more fibrous layers or two or more fibrous layers, the fibrous layers comprising a fibrous network comprising fibers of one or more types of second copolymers.
11. 11. The separator of claim 8, wherein the multilayer separator comprises one or more fiber layers or two or more fiber layers, a fiber layer comprising a network of core-shell fibers, and the first copolymer is included in a core or shell of the core-shell fibers.
12. 12. The separator of claim 11, wherein the core-shell fiber further comprises a second copolymer.
13. 13. The separator of claim 11, wherein the multilayer separator further comprises one or more types of fiber layers comprising a network of fibers comprising the first copolymer and fiber layers comprising a network of fibers comprising one or more types of second copolymer.
14. 14. The separator of claim 8, wherein the multilayer separator comprises one or more fibrous layers or two or more fibrous layers, a fibrous layer comprising a network of fibers comprising a mixture of the first and second copolymers.
15. 15. The separator of claim 14, wherein the multilayer separator further comprises one or more types of fiber layers comprising a network of fibers comprising the first copolymer and fiber layers comprising a network of fibers comprising one or more types of second copolymer.
16. 16. The separator of claim 10, wherein the second copolymer comprises any one or more of polyacrylonitrile, polyaniline, polypyrrole, melamine, polyurea, polyvinyl chloride, polyvinyl alcohol, polyethylene oxide, polymethyl methacrylate, polyacrylic acid, polylactic acid, polyimide, polyamideimide, polyaramid, polybenzimidazole, polypropylene, resorcinol-formaldehyde resin, melamine-formaldehyde resin, asphalt, sucrose, glucose, cellulose, and polyvinylidene fluoride.
17. 17. The separator of claim 1, wherein the separator does not have a porous substrate.
18. 18. The separator of claim 1, wherein the separator has a thickness of 8 μιη or less.
19. 19. A rechargeable lithium battery, the rechargeable lithium battery comprising: A positive electrode; a negative electrode, and The separator of claim 1, located between the positive electrode and the negative electrode.

Description

Separator for rechargeable lithium battery and rechargeable lithium battery including the same The present application claims priority from korean patent application No. 10-2024-0157090, filed on the korean intellectual property office at 11/7 of 2024, the entire disclosure of which is incorporated herein by reference. Technical Field The present disclosure relates to a separator for a rechargeable battery and a rechargeable battery including the same. Background As the presence of electronic devices using batteries, such as mobile phones, notebook computers, electric vehicles, and the like, increases, the demand for secondary batteries having high energy density and high capacity is increasing. Therefore, it may be advantageous to improve the performance of rechargeable lithium batteries. The rechargeable lithium battery includes a positive electrode and a negative electrode including an active material capable of intercalating and deintercalating lithium ions, and generates electric energy through oxidation and reduction reactions when lithium ions are deintercalated from the positive electrode and intercalated into the negative electrode and deintercalated from the negative electrode and intercalated into the positive electrode. Disclosure of Invention The present disclosure describes a separator for a rechargeable battery that lacks a porous substrate and provides desirable or improved heat resistance, low film resistance, and high adhesion. The present disclosure also describes a rechargeable battery including a separator for the rechargeable battery. One aspect of the present disclosure includes a separator for a rechargeable battery. A separator for a rechargeable battery includes one or more fibrous layers, wherein at least one of the one or more fibrous layers includes a fibrous network of fibers comprising a first copolymer, or at least one of the one or more fibrous layers includes a network of core-shell fibers comprising a first copolymer. The first copolymer includes a copolymer including a first structural unit including a unit derived from an aromatic-based unsaturated monomer, a second structural unit derived from a (meth) acrylic monomer including an alkyl group having 4 or more carbon atoms in the main chain in an ester moiety, and a third structural unit derived from a monomer including a sulfonic acid group. Here, the first structural unit, the second structural unit, and the third structural unit are included in the range of about 5mol% to about 80mol%, the range of about 10mol% to about 60mol%, and the range of about 5mol% to about 80mol%, respectively, with respect to 100mol% of the copolymer. Another aspect of the present disclosure includes a rechargeable battery. The rechargeable battery includes a positive electrode, a negative electrode, and a separator for the rechargeable battery between the positive electrode and the negative electrode. Since the separator for the rechargeable battery does not have a porous substrate, the overhang portion of the separator does not shrink when the battery is exposed to heat, thereby reducing or preventing short circuits and improving the reliability of the battery. The separator for a rechargeable battery according to one example embodiment may improve the capacity, safety, and life of the battery by providing desired or improved heat resistance, high adhesion, and low film resistance. Drawings The above and other objects, features and advantages of the present disclosure will become more apparent to those of ordinary skill in the art by describing in detail exemplary embodiments thereof with reference to the attached drawings, in which: Fig. 1 to 4 are cross-sectional views schematically illustrating a rechargeable lithium battery according to an example embodiment; fig. 5 to 9 are cross-sectional views schematically illustrating a separator for a rechargeable battery according to one example embodiment. Detailed Description Hereinafter, example embodiments of the present disclosure are described in detail. However, the embodiments are presented as examples and the disclosure is not limited thereto, and the disclosure is limited only by the scope of the appended claims. When an element such as a layer, film, region, or plate is described as being disposed "on" another element, it is intended to include not only the element being "directly on" the other element, but also other elements being present therebetween, unless otherwise specified herein. Singular may also include plural unless otherwise indicated herein. In addition, unless otherwise indicated, the term "a or B" may mean "including a, including B, or including a and B". In this specification, "combination thereof" may refer to a mixture, stack, compound, copolymer, alloy, blend or reaction product of components. Unless otherwise defined herein, "particle size D50" refers to the size of particles in the particle size distribution having a cumulative volume of 50% by volume. Particle s