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CN-122000626-A - Separator and electrochemical device including the same

CN122000626ACN 122000626 ACN122000626 ACN 122000626ACN-122000626-A

Abstract

The present invention relates to a separator comprising a substrate, an inorganic particle layer formed on at least either side of the substrate, and an adhesive layer formed on at least one of the inorganic particle layers, wherein when an adhesive force between a probe and a surface of the separator measured at a temperature x DEG C of a sample stage using a probe of an atomic force microscope having a spring constant of 40N/m, an average radius of 8nm, and a scanning speed of 0.5Hz is set to Fx, F40 is 1nN to 30nN, the separator satisfies the following formula 1.[ formula 1] F75/F40 is not less than 5.

Inventors

  • Jin Dongzai
  • Yin Zhemin
  • ZHANG DONGYI
  • LI CHUNBAO

Assignees

  • SK新技术株式会社
  • 爱思开高新信息电子材料株式会社

Dates

Publication Date
20260508
Application Date
20251021
Priority Date
20241107

Claims (20)

  1. 1. A separator includes a substrate, an inorganic particle layer formed on at least either side of the substrate, and an adhesive layer formed on at least one of the inorganic particle layers, Wherein when an adhesive force between a probe of an Atomic Force Microscope (AFM) having a spring constant of 40N/m, an average radius of 8nm and a scanning speed of 0.5Hz measured at a temperature x DEG C of a sample stage and a surface of a diaphragm is set to Fx, F40 is 1nN to 30nN, The separator satisfies the following formula 1, [ 1] F75/F40≥5。
  2. 2. The separator of claim 1, wherein the adhesive layer comprises a particulate polymer adhesive.
  3. 3. The separator of claim 1, wherein the adhesive layer comprises an acrylic-based polymeric adhesive.
  4. 4. The separator of claim 2, wherein the particulate polymer binder is a core-shell structure.
  5. 5. The separator of claim 4, wherein the polymer contained in the core of the particulate polymer binder has a glass transition temperature of 30 ℃ to 70 ℃.
  6. 6. The separator of claim 4, wherein the glass transition temperature of the polymer contained in the shell of the particulate polymer binder is 70 ℃ to 110 ℃.
  7. 7. The separator according to claim 4, wherein the glass transition temperature Tg of the polymer contained in the core, c and the glass transition temperature Tg of the polymer contained in the shell of the particulate polymer binder, s satisfy the following formula 2, [ 2] 50°C≤(Tg,c+Tg,s)/2≤90°C。
  8. 8. The separator of claim 1, wherein the adhesive layer comprises: Copolymers of repeating units derived from acrylic monomers, and Copolymers composed of repeating units derived from acrylic monomers and styrene.
  9. 9. The separator of claim 1, wherein the adhesive layer comprises a particulate acrylic-based polymer adhesive having an average particle size D50 of 400nm to 800 nm.
  10. 10. The separator of claim 1, wherein the F75 is 40nN to 300nN.
  11. 11. The separator of claim 1, wherein formula 1 satisfies F75/F40 ≡10.
  12. 12. The separator according to claim 1, wherein the adhesive layer comprises a particulate acrylic-based polymer adhesive comprising a repeating unit derived from a compound represented by the following chemical formula 1, [ Chemical formula 1] In the chemical formula 1 described above, a compound having the formula, R 1 is hydrogen or C 1-10 alkyl; R 2 is hydrogen or C 1-20 hydrocarbyl.
  13. 13. The separator of claim 1, wherein the inorganic particle layer comprises inorganic particles and a polymeric binder.
  14. 14. The separator according to claim 1, wherein the inorganic particle layer comprises inorganic particles having an average particle diameter D50 of 100nm to 1500 nm.
  15. 15. The separator according to claim 1, wherein the inorganic particle layer comprises first inorganic particles having an average particle diameter D50 of 100nm to 500nm and second inorganic particles having an average particle diameter D50 of 500nm to 1500 nm.
  16. 16. The separator of claim 1, wherein the inorganic particle layer comprises inorganic particles and a polymeric binder, the weight ratio of the inorganic particles to the polymeric binder being from 90:10 to 99:1.
  17. 17. The separator of claim 1, wherein the inorganic particle layer has a thickness of 0.5 to 3.0 μm.
  18. 18. The separator of claim 1, wherein the adhesive layer has a thickness of 0.05 μιη to 2.0 μιη.
  19. 19. An electrochemical device comprising a separator comprising a substrate, an inorganic particle layer formed on at least either side of the substrate, and an adhesive layer formed on at least one of the inorganic particle layers, Wherein when an adhesive force between a probe of an Atomic Force Microscope (AFM) having a spring constant of 40N/m, an average radius of 8nm and a scanning speed of 0.5Hz measured at a temperature x DEG C of a sample stage and a surface of a diaphragm is set to Fx, F40 is 1nN to 30nN, The separator satisfies the following formula 1, [ 1] F75/F40≥5。
  20. 20. An electrochemical device comprising a separator comprising a substrate, an inorganic particle layer formed on at least either side of the substrate, and an adhesive layer formed on at least one of the inorganic particle layers, Wherein when the number of cycles at which the internal resistance value of the electrochemical device increases by 30% from the initial resistance before the start of the charge-discharge cycle is set to C, C is 300 or more, Wherein the charge and discharge is performed as 1 cycle of 0.5C charge from 2.5V to 4.2V and 0.5C discharge from 4.2V to 2.5V after the electrochemical device is discharged to 2.5V.

Description

Separator and electrochemical device including the same Technical Field The present invention relates to a separator and an electrochemical device including the same. Background In recent years, attention to electrochemical devices and energy storage technologies thereof for use in mobile phones, notebook computers, electric vehicles, and the like is increasing dramatically. In particular, a separator, which is one of the main components determining the characteristics of a secondary battery as an electrochemical device, is actively studied. The separator is immersed in the electrolyte and functions as an ion channel, thus greatly affecting the physical properties of the secondary battery. In this regard, there is known a method of improving the thermal resistance performance of a separator by mixing and coating inorganic particles of high thermal resistance with a binder on a porous substrate, and a technique of sufficiently improving the internal resistance performance while securing the adhesion between the separator and an electrode is being developed and studied. Disclosure of Invention First, the technical problem to be solved It is an object of one embodiment to provide a separator in which the surface adhesion of the separator measured using a probe of an atomic force microscope (Atomic Force Microscope, AFM) with adjustable temperature is achieved as an adhesion within a prescribed range. It is an object of another embodiment to provide an electrochemical device including the separator. (II) technical scheme One embodiment provides a separator comprising a substrate, an inorganic particle layer formed on at least either side of the substrate, and an adhesive layer formed on at least one of the inorganic particle layers, wherein when an adhesive force between a probe and a surface of the separator measured at a temperature x DEG C of a sample stage using a probe of an atomic force microscope having a spring constant of 40N/m, an average radius of 8nm, and a scanning speed of 0.5Hz is set to Fx, F40 is 1nN to 30nN, the separator satisfies the following formula 1. [ 1] F75/F40≥5 In one embodiment, the adhesive layer may comprise a particulate polymer adhesive. In one embodiment, the adhesive layer may comprise an acrylic-based polymer adhesive. In one embodiment, the particulate polymer binder may be a core-shell structure. In one embodiment, the glass transition temperature of the polymer contained in the core of the particulate polymer binder may be 30 ℃ to 70 ℃, and/or the glass transition temperature of the polymer contained in the shell of the particulate polymer binder may be 70 ℃ to 110 ℃. In one embodiment, the glass transition temperature (Tg, c) of the polymer contained in the core and the glass transition temperature (Tg, s) of the polymer contained in the shell of the particulate polymer binder may satisfy the following formula 2. [ 2] 50°C≤(Tg,c+Tg,s)/2≤90°C In one embodiment, the adhesive layer may comprise a copolymer composed of repeating units derived from an acrylic-based monomer, and a copolymer composed of repeating units derived from an acrylic-based monomer and styrene. In one embodiment, the adhesive layer may comprise a particulate polymer adhesive or a particulate acrylic-based polymer adhesive having an average particle diameter (D50) of 400nm to 800 nm. In one embodiment, the F75 may be 40nN to 300nN. In one embodiment, formula 1 may satisfy F75/F40≥10. In one embodiment, the adhesive layer may include a particle-type polymer adhesive or a particle-type acrylic-based polymer adhesive including a repeating unit derived from a compound represented by chemical formula 1 below. [ Chemical formula 1] In the chemical formula 1, R 1 is hydrogen or C 1-10 alkyl, and R 2 is hydrogen or C 1-20 alkyl. In one embodiment, the inorganic particle layer may include inorganic particles and a polymer binder. In one embodiment, the inorganic particle layer may include inorganic particles having an average particle diameter (D50) of 100nm to 1500 nm. In one embodiment, the inorganic particle layer may include first inorganic particles having an average particle diameter (D50) of 100nm to 500nm and second inorganic particles having an average particle diameter (D50) of 500nm to 1500 nm. In one embodiment, the inorganic particle layer may include inorganic particles and a polymer binder, and in this case, the weight ratio of the inorganic particles to the polymer binder may be 90:10 to 99:1. In one embodiment, the inorganic particle layer may have a thickness of 0.5 μm to 3.0 μm. In one embodiment, the adhesive layer may have a thickness of 0.05 μm to 2.0 μm. Another embodiment provides an electrochemical device including a separator including a substrate, an inorganic particle layer formed on at least either side of the substrate, and an adhesive layer formed on at least one of the inorganic particle layers, wherein when an adhesive force between a probe of an Atomic Force Microscope (AFM) havin