Nonaqueous electrolyte secondary battery

Patent metadata

Field	Value
Publication number	US-2023055772-A1
Application number	US-202217979108-A
Country	US
Kind code	A1
Filing date	Nov 2, 2022
Priority date	Apr 9, 2019
Publication date	Feb 23, 2023
Grant date	—

Abstract

A nonaqueous electrolyte secondary battery includes a positive electrode including a positive electrode collector, a positive electrode active material layer on part of the surface of the positive electrode collector, and an insulating layer on another part of the surface of the positive electrode collector; a negative electrode including a negative electrode collector; and a negative electrode active material layer on part of the surface of the negative electrode collector; a separator that insulates the positive and negative electrodes; and a nonaqueous electrolyte. A width of the negative electrode active material layer is wider than the positive electrode active material layer. The insulating layer protrudes from the negative electrode active material layer; and exhibits a thermal shrinkage factor of 13% or less in a direction parallel to the surface of a square insulating layer sample having a side length of 5 cm and heated at 150° C. for 1 hour.

First claim

What is claimed is:

1 . A nonaqueous electrolyte secondary battery, comprising:
a positive electrode; a negative electrode; a separator that insulates the positive electrode and the negative electrode; and a nonaqueous electrolyte, wherein the positive electrode includes:
a positive electrode collector;
a positive electrode active material layer containing a positive electrode active material and provided on part of the surface of the positive electrode collector; and
an insulating layer provided on another part of the surface of the positive electrode collector, so as to be adjacent to the positive electrode active material layer;
the negative electrode includes:
a negative electrode collector; and
a negative electrode active material layer containing a negative electrode active material and provided on part of the surface of the negative electrode collector;
a width of the negative electrode active material layer is wider than a width of the positive electrode active material layer, and the insulating layer contains an inorganic filler and a binder; protrudes outward in a width direction from the negative electrode active material layer; and is configure to exhibit a value of 13% or less of a thermal shrinkage factor in a direction parallel to the surface of an evaluation sample of an insulating layer formed to a square shape having a length of each side of 5 cm and heated at 150° C. for 1 hour.

2 . The nonaqueous electrolyte secondary battery according to claim 1 , wherein the inorganic filler contains plate-shaped particles.

3 . The nonaqueous electrolyte secondary battery according to claim 2 , wherein the inorganic filler contains plate-shaped particles having an average aspect ratio of 3 or higher.

4 . The nonaqueous electrolyte secondary battery according to claim 1 , wherein the inorganic filler is at least either one of boehmite powder and alumina powder.

5 . The nonaqueous electrolyte secondary battery according to claim 1 , wherein, in the insulating layer, the proportion of the binder relative to the total of the inorganic filler and the binder is lower than 30 mass %.

6 . The nonaqueous electrolyte secondary battery according to claim 1 , wherein the average thickness of the insulating layer is 10 μm or less.

Assignees

• Toyota Motor Co Ltd

Inventors

• Yamada Takanobu
• Kaneko Tetsuya

Classifications

• H01M2300/0025

  Organic electrolyte · CPC title

• Y02E60/10

  Energy storage using batteries · CPC title

• H01M4/62

  Selection of inactive substances as ingredients for active masses, e.g. binders, fillers · CPC title

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• H01M10/0587

  of accumulators having only wound construction elements, i.e. wound positive electrodes, wound negative electrodes and wound separators · CPC title