Nonaqueous electrolyte secondary battery

Patent metadata

Field	Value
Publication number	US-2018013136-A1
Application number	US-201515521117-A
Country	US
Kind code	A1
Filing date	Oct 22, 2015
Priority date	Oct 22, 2014
Publication date	Jan 11, 2018
Grant date	—

Abstract

A nonaqueous electrolyte secondary battery includes a positive electrode, a nonaqueous electrolytic solution, and a negative electrode. The negative electrode includes a negative electrode current collector and a negative electrode active material layer which is formed on the negative electrode current collector. The negative electrode active material layer has a first region and a second region. The first region is a region formed on a surface of the negative electrode current collector and contains lithium titanium composite oxide as a major component. The second region is a region including a surface of the negative electrode active material layer and contains lithium titanium composite oxide as a major component and further contains silicon oxide.

First claim

What is claimed is:

1 . A nonaqueous electrolyte secondary battery characterized by comprising:
a positive electrode; a nonaqueous electrolytic solution; and a negative electrode, the negative electrode including a negative electrode current collector and a negative electrode active material layer which is formed on the negative electrode current collector, the negative electrode active material layer having a first region and a second region, the first region being a region formed on a surface of the negative electrode current collector and contains lithium titanium composite oxide as a major component, and the second region being a region including a surface of the negative electrode active material layer and contains lithium titanium composite oxide as a major component and further contains silicon oxide, wherein a content of silicon oxide in the first region and M 2 SiO satisfy the following relationship:
M 1 SiO <M 2 SiO
wherein M 1 SiO represents the content of silicon oxide in the first region in terms of mass %.

2 . The nonaqueous electrolyte secondary battery according to claim 1 , wherein
a ratio of an average thickness of the second region to an average thickness of the negative electrode active material layer is 1% to 50%.

3 . The nonaqueous electrolyte secondary battery according to claim 1 , wherein
a content of lithium titanium composite oxide in the second region and a content of silicon oxide in the second region satisfy the following relationship:
1 M 2 SiO /( M 2 LTO +M 2 SiO )×100≦7

wherein M 2 LTO represents the content of lithium titanium composite oxide in the second region in terms of mass %, and M SiO represents the content of silicon oxide in the second region in terms of mass %.

4 . The nonaqueous electrolyte secondary battery according to claim 1 , wherein
a mass per unit area of the negative electrode active material layer in the first region is 30 mg/cm 2 to 50 mg/cm 2 .

5 . The nonaqueous electrolyte secondary battery according to claim 1 , wherein
an overall density of the negative electrode active material layer is 2 g/cm 3 to 3 g/cm 3 .

6 . The nonaqueous electrolyte secondary battery according to claim 1 , wherein
the first region contains silicon oxide.

7 . The nonaqueous electrolyte secondary battery according to claim 1 , characterized in that
the content of silicon oxide in the first region is zero.

Assignees

• Toyota Motor Co Ltd

Inventors

• Mizuno Tomoyuki

Classifications

• H01M4/131 Primary

  Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx · CPC title

• H01M4/485

  of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy (H01M4/505, H01M4/525 take precedence) · 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

• H01M4/366

  as layered products · CPC title