CN-122025537-A - Battery cell, battery and electricity utilization device

CN122025537ACN 122025537 ACN122025537 ACN 122025537ACN-122025537-A

Abstract

The application relates to a battery cell, a battery and an electric device. The battery monomer comprises an electrode plate, the electrode plate comprises a current collector and a film layer arranged on at least one side of the current collector, the film layer comprises an active substance and a plurality of fluorinated polymers, the crystallinity of one fluorinated polymer in the plurality of fluorinated polymers is recorded as X c1 percent, the cold crystallization temperature is recorded as T c1 ℃, the crystallinity of the other fluorinated polymer in the plurality of fluorinated polymers is recorded as X c2 percent, the cold crystallization temperature is recorded as T c2 ℃, and the fluorinated polymers meet the requirements of 20 percent to less than or equal to (X c2 -X c1 )/X c1 ≤400%,30%≤(T c2 -T c1 )/T c1 <250 percent).

Inventors

LI BAIQING
Peng Shuangjuan
PENG LIN
JIN HAIZU
ZHAO FENGGANG
WU KAI

Assignees

宁德时代新能源科技股份有限公司

Dates

Publication Date: 20260512
Application Date: 20231103

Claims (12)

1. A battery cell comprises an electrode plate, wherein the electrode plate comprises a current collector and a film layer arranged on at least one side of the current collector, the film layer comprises an active substance and multiple fluorinated polymers, The crystallinity of one of the plurality of fluorinated polymers is recorded as X c1 percent, and the cold crystallization temperature is recorded as T c1 ℃; the crystallinity of another fluoropolymer of the plurality of fluoropolymers is noted as X c2 %, the cold crystallization temperature is noted as T c2 ℃, Wherein the plurality of fluorinated polymers satisfy that the X c2 -X c1 )/X c1 ≤400%,30%≤(T c2 -T c1 )/T c1 is less than or equal to 20 percent (less than 250 percent).
2. The battery cell according to claim 1, wherein, 40%≤(X c2 -X c1 )/X c1 <400%; Optionally, X c2 -X c1 is equal to or greater than 10, further optionally, 10 is equal to or greater than c2 -X c1 is equal to or less than 45, further optionally, 10 is equal to or greater than c2 -X c1 is equal to or greater than 40.
3. The battery cell of claim 2, wherein 0<X c1 ≤28, optionally 10≤X c1 ≤25; And/or 30≤X c2 ≤50; alternatively, the process may be carried out in a single-stage, X c2 is less than or equal to 35 and less than or equal to 50.
4. The battery cell according to any one of claim 1 to 3, wherein, 35% Or less (T c2 -T c1 )/T c1 <250%, alternatively 39% or less (T c2 -T c1 )/T c1 . Ltoreq.213%; Alternatively, T c2 -T c1 is greater than or equal to 25, further alternatively, T c2 -T c1 is greater than or equal to 25 and less than or equal to 100, and further alternatively, T c2 -T c1 is greater than or equal to 35 and less than or equal to 85.
5. The battery cell according to claim 4, wherein, 35< T c1 < 100, alternatively 40 < T c1 < 90; and/or 115≤T c2 ≤140; alternatively, the process may be carried out in a single-stage, T c2 is 125-135.
6. The battery cell according to any one of claims 1 to 5, wherein, One of the plurality of fluorinated polymers has a glass transition temperature T g1 ℃,-30≤T g1 of less than or equal to 40, and/or The glass transition temperature of another one of the plurality of fluorinated polymers is T g2 ℃,-30≤T g2 to or less than 40; Alternatively, the process may be carried out in a single-stage, Each of the plurality of fluoropolymers independently includes at least one of a compound represented by formula (AI) to a compound represented by formula (AIII), A compound of the formula (AI), The formula (AII), In the formula (AI) and the formula (AII), R 11 、R 12 、R 13 and R 14 each independently include a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, a substituted or unsubstituted C1-C3 alkyl group, or a substituted or unsubstituted C1-C3 alkoxy group, and at least one of R 11 、R 12 、R 13 and R 14 contains a fluorine atom; the compound of formula (AIII), In formula (AIII), R 15 comprises a single bond, substituted or unsubstituted C1-C3 alkyl; p is selected from positive integers of 1 to 3; n is a positive integer from 1000 to 30000.
7. The battery cell according to any one of claims 1 to 6, wherein, One of the plurality of fluoropolymers has a molecular weight of W 1 g/mol, The molecular weight of another fluoropolymer of the plurality of fluoropolymers is W 2 g/mol, The plurality of fluoropolymers satisfies 0<W 1/ W 2 <1; Alternatively, 2.0X10 5 ≤W 1 ≤1.0×10 6 ;5.0×10 5 ≤W 2 ≤1.2×10 6 .
8. The battery cell according to any one of claims 1 to 7, wherein the total mass content of the plurality of fluoropolymers is 5% or less, optionally 0.05% to 5%, based on the total mass of the film layer; Alternatively, the process may be carried out in a single-stage, The mass content of the first fluoropolymer is less than or equal to 4% based on the total mass of the film layer; Alternatively, the process may be carried out in a single-stage, The mass content of the second fluoropolymer is less than or equal to 4% based on the total mass of the film layer.
9. The battery cell according to any one of claims 1 to 8, wherein the electrode tab comprises a positive electrode tab comprising a positive electrode current collector and a positive electrode film layer disposed on at least one side of the positive electrode current collector, the positive electrode film layer comprising a positive electrode active material, a first fluoropolymer, and a second fluoropolymer; Alternatively, the process may be carried out in a single-stage, The mass content of the first fluoropolymer and the total mass content of the second fluoropolymer are 0.05% to 2.5% based on the total mass of the positive electrode film layer; Alternatively, the process may be carried out in a single-stage, The mass content of the first fluoropolymer is less than the mass content of the second fluoropolymer based on the total mass of the positive electrode film layer; Further alternatively, the method may comprise, in a further alternative, The mass content of the first fluorinated polymer is less than or equal to 2%, optionally 0.05 to 1% based on the total mass of the positive electrode film layer; Further alternatively, the method may comprise, in a further alternative, The mass content of the second fluorinated polymer is less than or equal to 2%, optionally 1-2%, optionally 1.2-2% based on the total mass of the positive electrode film layer; further alternatively, the positive electrode active material includes at least one of a lithium-containing phosphate compound and a layered structure positive electrode active material.
10. The battery cell of any one of claims 1 to 8, wherein the electrode tab comprises a negative electrode tab comprising a negative electrode current collector and a negative electrode film layer disposed on at least one side of the negative electrode current collector, the negative electrode film layer comprising a negative electrode active material, a first fluoropolymer, and a second fluoropolymer; Alternatively, the process may be carried out in a single-stage, The mass content of the first fluoropolymer and the total mass content of the second fluoropolymer are 0.05% to 5% based on the total mass of the negative electrode film layer; Alternatively, the process may be carried out in a single-stage, The mass content of the first fluorinated polymer is greater than the mass content of the second fluorinated polymer based on the total mass of the negative electrode film layer, or The mass content of the first fluorinated polymer is smaller than the mass content of the second fluorinated polymer based on the total mass of the negative electrode film layer Further alternatively, the method may comprise, in a further alternative, The mass content of the first fluorinated polymer is less than or equal to 4%, optionally 0.5 to 4%, optionally 2 to 4% based on the total mass of the negative electrode film layer; Alternatively, the process may be carried out in a single-stage, The mass content of the second fluorinated polymer is less than or equal to 4%, alternatively 0.4% to 2%, further alternatively 0.4% to 1%, based on the total mass of the negative electrode film layer; further alternatively, the negative electrode active material includes at least one of natural graphite, artificial graphite, soft carbon, hard carbon, a silicon-based material, a tin-based material, and lithium titanate.
11. A battery comprising the battery cell according to any one of claims 1 to 10.
12. An electrical device comprising the battery according to claim 11.

Description

Battery cell, battery and electricity utilization device The application is based on the application number 202311460439.8, the application date 2023, 11 and 03, and the application is a divisional application of the application named electrode plate, battery and electricity utilization device of New energy science and technology Co., ltd in the Ningde era. Technical Field The application relates to a battery cell, a battery and an electric device. Background The battery has characteristics of high capacity, long life, and the like, and thus is widely used in electronic devices such as mobile phones, notebook computers, battery cars, electric automobiles, electric airplanes, electric ships, electric toy automobiles, electric toy ships, electric toy airplanes, electric tools, and the like. As the battery application range increases, the requirements for battery performance become increasingly stringent. However, the cycle life and storage life of the battery are still poor, and further improvement is required. Disclosure of Invention The present application has been made in view of the above problems, and an object thereof is to provide a battery cell, a battery, and an electric device. In a first aspect, the application provides a battery cell comprising an electrode sheet comprising a current collector and a film layer disposed on at least one side of the current collector, the film layer comprising an active material and a plurality of fluorinated polymers, The crystallinity of one of the plurality of fluorinated polymers is recorded as X c1 percent, and the cold crystallization temperature is recorded as T c1 ℃; The crystallinity of another fluoropolymer of the plurality of fluoropolymers is noted as X c2%, the cold crystallization temperature is noted as T c2 ℃, Wherein, the multiple fluorinated polymers meet the requirement of 20 percent to less than or equal to (X c2-Xc1)/Xc1≤400%,30%≤(Tc2-Tc1)/Tc1 to less than 250 percent). Therefore, in the embodiment of the application, the crystallinity X c1% of the first fluorinated polymer is relatively smaller, the cold crystallization temperature T c1 ℃ is relatively lower, the flexibility of a molecular chain is higher, the first fluorinated polymer forms in-situ gel on the surface of active material particles, the solid-liquid interface performance is improved, the first fluorinated polymer and the second fluorinated polymer are similar in structure, compared with the first fluorinated polymer, the crystallinity X c2% of the second fluorinated polymer is relatively larger, the cold crystallization temperature T c2 ℃ is relatively higher, the higher the energy requirement for releasing the inter-molecular constraint is, the self cohesive energy density is better improved, the swelling deformation is reduced, and the binding force between active materials is improved. In some embodiments, 40% or less (X c2-Xc1)/Xc1 <400%; optionally X c2-Xc1. Gtoreq.10; further optionally 10. Ltoreq.X c2-Xc1. Ltoreq.45; further optionally 10. Ltoreq.X c2-Xc1. Ltoreq.40). Embodiments of the present application may further improve cycle performance and storage performance of the electrode sheet when applied to a battery cell by further selection of the crystallinity and cold crystallization temperature of the fluoropolymer. In some embodiments 0<X c1≤28; alternatively, the process may be carried out in a single-stage, X c1 is more than or equal to 10 and less than or equal to 25; X c1 is more than or equal to 10 less than or equal to 25. In some embodiments, 35% or less (T c2-Tc1)/Tc1 <250%; optionally, 39% or less (T c2-Tc1)/Tc1. Ltoreq.213%; optionally, T c2-Tc1. Gtoreq.25; further optionally, 25. Ltoreq.T c2-Tc1. Ltoreq.100; further optionally, 35. Ltoreq.T c2-Tc1. Ltoreq.85). In some embodiments, further optionally, 35< T c1≤100; alternatively, T c1 is 40-90; and/or 115≤T c2≤140; alternatively, 125≤T c2≤135. In some embodiments, one of the plurality of fluoropolymers has a glass transition temperature T g1℃,-30≤Tg1≤40. In some embodiments, another fluoropolymer of the plurality of fluoropolymers has a glass transition temperature T g2℃,-30≤Tg2≤40. In some embodiments, each of the plurality of fluoropolymers independently includes at least one of a compound represented by formula (AI) to a compound represented by formula (AIII), A compound of the formula (AI),The formula (AII), In the formula (AI) and the formula (AII), R 11、R12、R13 and R 14 each independently include a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, a substituted or unsubstituted C1-C3 alkyl group, or a substituted or unsubstituted C1-C3 alkoxy group, and at least one of R 11、R12、R13 and R 14 contains a fluorine atom; the compound of formula (AIII), In formula (AIII), R 15 comprises a single bond, substituted or unsubstituted C1-C3 alkyl; p is selected from positive integers of 1 to 3; n is a positive integer from 1000 to 30000. In some embodiments, one of the plurality of fluoropolymers has