Nonaqueous electrolyte secondary battery

Patent metadata

Field	Value
Publication number	US-9660262-B2
Application number	US-201314427135-A
Country	US
Kind code	B2
Filing date	Sep 9, 2013
Priority date	Sep 11, 2012
Publication date	May 23, 2017
Grant date	May 23, 2017

Abstract

A positive electrode for a nonaqueous electrolyte secondary battery according to the present invention includes particles A of a lamellar type lithium transition metal oxide and particles B of a spinel type lithium transition metal oxide, as a positive active material, at a ratio within the range of A:B=20:80 to 80:20 (weight ratio), in which a particle size distribution of the positive active material has a peak based on the particles A and a peak based on the particles B within the range of 1 to 50 μm. In the integrated distribution curve of the particle diameter, a particle diameter A(D50) at a degree of accumulation of the particles A of 50% and a particle diameter B(D50) at a degree of accumulation of the particles B of 50% satisfy the following expression (1), and a particle diameter A(D95) at a degree of accumulation of the particles A of 95% and a particle diameter B(D5) at a degree of accumulation of the particles B of 5% satisfy the following expression (2):

B ( D 50)− A ( D 50)≧5 μm  Expression (1)

B ( D 5)> A ( D 95)  Expression (2).

First claim

The invention claimed is:

1. A nonaqueous electrolyte secondary battery, comprising particles A of a lamellar type lithium transition metal oxide and particles B of a spinel type lithium transition metal oxide, as a positive active material, at a ratio within the range of A:B=20:80 to 80:20 (weight ratio), wherein
a particle size distribution of the positive active material has a peak based on the particles A and a peak based on the particles B within the range of 1 to 50 μm,
in a particle size distribution in terms of volume, a particle diameter A(D50) at a degree of accumulation of the particles A of 50% and a particle diameter B(D50) at a degree of accumulation of the particles B of 50% satisfy the following expression (1), and a particle diameter A(D95) at a degree of accumulation of the particles A of 95% and a particle diameter B(D5) at a degree of accumulation of the particles B of 5% satisfy the following expression (2):
B ( D 50)− A ( D 50)≧5 μm  Expression (1)

B ( D 5)> A ( D 95)  Expression (2),

the particle diameter A(D50) at a degree of accumulation of the particles A of 50% is less than 5 μm, and
the lamellar type lithium transition metal oxide is a lithium transition metal oxide represented by a general formula LiNi x Mn y Co z Q a O 2 (Q denotes at least one element selected from the group consisting of group 2 to group 15 elements in the Periodic Table of the Elements, and x+y+z+a=1, x>0, y>0, z>0 and 0.1≧a>0).

2. A nonaqueous electrolyte secondary battery, comprising particles A of a lamellar type lithium transition metal oxide and particles B of a spinel type lithium transition metal oxide, as a positive active material, at a ratio within the range of A:B=20:80 to 80:20 (weight ratio), wherein
a particle size distribution of the positive active material has a peak based on the particles A and a peak based on the particles B within the range of 1 to 50 μm,
in a particle size distribution in terms of volume, a particle diameter A(D50) at a degree of accumulation of the particles A of 50% and a particle diameter B(D50) at a degree of accumulation of the particles B of 50% satisfy the following expression (3):
B ( D 50)/ A ( D 50)>4  Expression (3),

the particle diameter A(D50) at a degree of accumulation of the particles A of 50% is less than 5 μm, and
the lamellar type lithium transition metal oxide is a lithium transition metal oxide represented by a general formula LiNi x Mn y Co z Q a O 2 (Q denotes at least one element selected from the group consisting of group 2 to group 15 elements in the Periodic Table of the Elements, and x+y+z+a=1, x>0, y>0, z>0 and 0.1≧a>0).

3. The nonaqueous electrolyte secondary battery according to claim 1 , wherein each of a half-value width of the peak based on the particles A and a half-value width of the peak based on the particles B is 20 μm or less.

4. The nonaqueous electrolyte secondary battery according to claim 1 , wherein a minimum particle diameter of the particles B is larger than a maximum particle diameter of the particles A.

5. The nonaqueous electrolyte secondary battery according to claim 1 , wherein the x in the general formula is within the range of 0.5≧x.

6. The nonaqueous electrolyte secondary battery according to claim 1 , comprising the particles A of a lamellar type lithium transition metal oxide and the particles B of a spinel type lithium transition metal oxide, as the positive active material, at a ratio within the range of A: B=20:80 to 50:50 (weight ratio).

7. The nonaqueous electrolyte secondary battery according to claim 1 , comprising a separator, wherein the separator is provided with an inorganic compound on a positive electrode side surface.

8. The nonaqueous electrolyte secondary battery according to claim 2 , wherein each of a half-value width of the peak based on the particles A and a half-value width of the peak based on the particles B is 20 μm or less.

9. The nonaqueous electrolyte secondary battery according to claim 2 , wherein a minimum particle diameter of the particles B is larger than a maximum particle diameter of the particles A.

10. The nonaqueous electrolyte secondary battery according to claim 2 , wherein the x in the general formula is within the range of 0.5≧x.

11. The nonaqueous electrolyte secondary battery according to claim 2 , comprising the particles A of a lamellar type lithium transition metal oxide and the particles B of a spinel type lithium transition metal oxide, as the positive active material, at a ratio within the range of A: B=20:80 to 50:50 (weight ratio).

12. The nonaqueous electrolyte secondary battery according to claim 2 , comprising a separator, wherein the separator is provided with an inorganic compound on a positive electrode side surface.

Assignees

• Gs Yuasa Int Ltd

Inventors

• Uebo Yasushi
• Anami Keisuke

Classifications

• 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

• H01M2004/021

  Physical characteristics, e.g. porosity, surface area · CPC title

• H01M4/131 Primary

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

• H01M4/505

  of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy · CPC title

• H01M10/052

  Li-accumulators · CPC title