Search

CN-122003743-A - Nonaqueous electrolyte secondary battery and electrode using the same

CN122003743ACN 122003743 ACN122003743 ACN 122003743ACN-122003743-A

Abstract

A nonaqueous electrolyte secondary battery comprising a1 st electrode, a 2 nd electrode, a nonaqueous electrolyte, and a separator interposed between the 1 st electrode and the 2 nd electrode, wherein the 1 st electrode comprises a1 st current collector and a1 st active material layer supported on the 1 st current collector, the 1 st active material layer comprises a1 st active material, a binder, and an additive, the additive is a polymer material having a melting point or a thermal decomposition temperature of 200 ℃ or more and 500 ℃ or less, the polymer material forms a plurality of island-like regions in a cross section of the 1 st active material layer and is dispersed, and when the 1 st active material layer is heated from 25 ℃ to 400 ℃ or more, the area of the island-like regions in the cross section of the 1 st active material layer is enlarged to 4 times or more.

Inventors

  • NAKAYAMA TAKAHITO
  • SATO MAHO
  • NISHINO HAJIME

Assignees

  • 松下知识产权经营株式会社

Dates

Publication Date
20260508
Application Date
20241011
Priority Date
20231013

Claims (12)

  1. 1. A nonaqueous electrolyte secondary battery comprising a1 st electrode, a 2 nd electrode, a nonaqueous electrolyte, and a separator interposed between the 1 st electrode and the 2 nd electrode, The 1 st electrode comprises a1 st current collector and a1 st active material layer supported on the 1 st current collector, The 1 st active material layer contains a1 st active material, a binder and additives, The additive is a polymeric material having a melting point or thermal decomposition temperature of 200 ℃ or more and 500 ℃ or less, In the cross section of the 1 st active material layer, the polymer material forms a plurality of island-like regions and is dispersed, When the temperature of the 1 st active material layer is raised from 25 ℃ to 400 ℃ or higher, the area of the island-like region in the cross section of the 1 st active material layer is enlarged to 4 times or higher.
  2. 2. The nonaqueous electrolyte secondary battery according to claim 1, wherein an aspect ratio DL/DW of particles of the polymer material is 1.5 or less, DL is a length DL of a major axis defining a maximum diameter, and DW is a length DW of a minor axis perpendicular to the major axis at a midpoint of the major axis.
  3. 3. The nonaqueous electrolyte secondary battery according to claim 1, the polymer material having a linear structure.
  4. 4. The nonaqueous electrolyte secondary battery according to claim 1, wherein a ratio η100/η1 between a complex viscosity η1 at an angular frequency of 1 rad/sec and a complex viscosity η100 at an angular frequency of 100 rad/sec at 350 ℃ of the polymer material is 5 or less.
  5. 5. The nonaqueous electrolyte secondary battery according to claim 1, wherein the polymer material has a main chain containing a phenylene group and a thioether group.
  6. 6. The nonaqueous electrolyte secondary battery according to claim 5, wherein the main chain has a repeating structure represented by the following formula, Wherein n is an arbitrary integer.
  7. 7. The nonaqueous electrolyte secondary battery according to claim 6, wherein the polymer material contains polyphenylene sulfide.
  8. 8. The nonaqueous electrolyte secondary battery according to claim 1, wherein the polymer material contains chlorine ions in a mass ratio of 10ppm or more and 1000ppm or less.
  9. 9. The nonaqueous electrolyte secondary battery according to claim 1, wherein a content of the polymer material contained in the 1 st active material layer is 0.01 mass% or more and 5 mass% or less.
  10. 10. The nonaqueous electrolyte secondary battery according to claim 1, wherein the 1 st active material contains at least 1 selected from a carbon material and a silicon-containing material.
  11. 11. The nonaqueous electrolyte secondary battery according to claim 1, wherein the 1 st active material contains a lithium-containing transition metal oxide, The lithium-containing transition metal oxide contains a lithium nickel oxide containing lithium and Ni and having a layered rock salt type crystal structure, The proportion of Ni in the metal elements other than Li contained in the lithium nickel oxide is 50 at% or more.
  12. 12. An electrode for a secondary battery comprising a1 st collector and a1 st active material layer supported on the 1 st collector, The 1 st active material layer contains a1 st active material, a binder and additives, The additive is a polymeric material having a melting point or thermal decomposition temperature of 200 ℃ or more and 500 ℃ or less, In the cross section of the 1 st active material layer, the polymer material forms a plurality of island-like regions and is dispersed, When the temperature of the 1 st active material layer is raised from 25 ℃ to 400 ℃ or higher, the area of the island-like region in the cross section of the 1 st active material layer is enlarged to 4 times or higher.

Description

Nonaqueous electrolyte secondary battery and electrode using the same Cross reference to related applications The present disclosure claims priority from japanese patent office, japanese patent application No. 2023-177851, 10/13, based on the benefit of priority, the entire contents of the above patent application being incorporated by reference into the present specification. Technical Field The present disclosure relates to a nonaqueous electrolyte secondary battery and an electrode using the same. Background Patent document 1 proposes a nonaqueous electrolyte battery including a positive electrode mixture layer, a negative electrode including a negative electrode mixture layer, and a nonaqueous electrolyte, wherein a polymer obtained by polymerizing at least one monomer molecule having a unit structure of-C 6H4-SO2-、-C6H4-S-、-C6H4 -O-is added to the positive electrode mixture layer and/or the negative electrode mixture layer, and the positive electrode mixture layer contains a positive electrode active material and the negative electrode mixture layer contains a negative electrode active material. Patent document 2 proposes a negative electrode for a lithium secondary battery, which is characterized by comprising a lithium metal layer and a protective layer having a multilayer structure formed on the lithium metal layer, wherein the protective layer comprises a1 st protective layer comprising a carbon nanotube-ion conductive polymer composite material and a 2 nd protective layer comprising a carbon nanotube-conductive polymer composite material. Prior art literature Patent literature Patent document 1 Japanese patent laid-open publication No. 2003-007303 Patent document 2 Japanese patent application laid-open No. 2019-506715 Disclosure of Invention The invention aims to solve the problems The higher the energy density of the secondary battery, the higher the safety is required. Among them, it is important to reduce heat generation caused by internal short circuits. When an internal short circuit occurs in a battery, even if the short circuit portion is small, the separator melts due to joule heat caused by a short circuit current, and a larger short circuit portion is formed. When the short-circuit portion is enlarged and the short-circuit current is increased, the battery temperature increases with acceleration. The higher the energy density of the secondary battery, the more joule heat caused by the short-circuit current increases. Means for solving the problems An aspect of the present invention relates to a nonaqueous electrolyte secondary battery including a 1 st electrode, a 2 nd electrode, a nonaqueous electrolyte, and a separator interposed between the 1 st electrode and the 2 nd electrode, wherein the 1 st electrode includes a 1 st current collector and a 1 st active material layer supported on the 1 st current collector, the 1 st active material layer contains a 1 st active material, a binder, and an additive, the additive is a polymer material having a melting point or a thermal decomposition temperature of 200 ℃ or more and 500 ℃ or less, the polymer material forms a plurality of island-like regions in a cross section of the 1 st active material layer and is dispersed, and when the 1 st active material layer is heated from 25 ℃ to 400 ℃ or more, an area of the island-like regions in the cross section of the 1 st active material layer is enlarged to 4 times or more. Another aspect of the present invention relates to an electrode for a secondary battery, comprising a1 st collector and a1 st active material layer supported on the 1 st collector, wherein the 1 st active material layer contains a1 st active material, a binder, and an additive, and the additive is a polymer material having a melting point or a thermal decomposition temperature of 200 ℃ or more and 500 ℃ or less, wherein the polymer material forms and disperses a plurality of island-like regions in a cross section of the 1 st active material layer, and when the 1 st active material layer is heated from 25 ℃ to 400 ℃ or more, an area of the island-like regions in the cross section of the 1 st active material layer is enlarged by 4 times or more. Effects of the invention According to the present invention, both high safety and good battery performance can be achieved. Although the novel features of the invention are set forth in the appended claims, other objects and features of the invention will be apparent from the following detailed description of the invention when taken in conjunction with the accompanying drawings, in which both the nature and construction of the invention will be more clearly understood. Drawings Fig. 1 is a longitudinal sectional view schematically showing the internal structure of a secondary battery according to an embodiment of the present disclosure. Detailed Description Embodiments of the present disclosure are illustrated below, but the present disclosure is not limited by the examples illustrated below