Lithium ion battery

Patent metadata

Field	Value
Publication number	US-9923239-B2
Application number	US-201214118288-A
Country	US
Kind code	B2
Filing date	May 15, 2012
Priority date	Jul 14, 2011
Publication date	Mar 20, 2018
Grant date	Mar 20, 2018

Abstract

The purpose of the present invention is to provide a lithium-ion battery that exhibits excellent long-term life properties, does not suffer from rapid capacity degradation, and exhibits excellent charging/discharging characteristics in low-temperature environments. The present invention is directed to a lithium ion battery comprising: a negative electrode which comprises a negative electrode active material containing at least one of a graphite and an amorphous carbon, conductive additives containing a graphite, and a binder; a nonaqueous electrolyte solution; and a positive electrode containing a positive electrode active material capable of occluding and releasing lithium. The negative electrode active material has a spherical or massive shape, the conductive additives have a platy shape, and a part of an edge surface of the conductive additives contacts a surface of the negative electrode active material. The nonaqueous electrolyte solution contains a solvent, and an additive which reductively decomposes at a voltage lower than a reduction voltage of the solvent.

First claim

The invention claimed is:

1. A lithium ion battery comprising:
a negative electrode including a negative electrode active material containing at least one of a graphite and an amorphous carbon, a conductive additive, and a binder;
a nonaqueous electrolyte solution; and
a positive electrode including a positive electrode active material capable of occluding and releasing lithium,
wherein the negative electrode active material has a particulate shape;
the conductive additive comprises a platy graphite with a Raman peak intensity ratio I G /I D of 6-12, wherein the I G is an intensity of a peak in a G band near 1,580 cm −1 to 1,600 cm −1 corresponding to the in-plane vibration mode and the I D is an intensity of a peak in a D band near 1360 cm −1 derived from in-plane defects, and a thickness of 0.05 μm or larger and less than 0.1 μm,
at least a part of an edge surface of the conductive additive contacts with a surface of the negative electrode active material, and
the nonaqueous electrolyte solution contains a solvent, and an additive which reductively decomposes at a voltage lower than a reduction voltage of the solvent.

2. The lithium ion battery according to claim 1 , wherein the nonaqueous electrolyte solution comprises a cyclic sulfonate ester or a chain sulfonate ester including two sulfonyl groups, as the additive.

3. The lithium ion battery according to claim 1 , wherein the nonaqueous electrolyte solution comprises a cyclic sulfonate ester including two sulfonyl groups and being represented by the following formula (1), as the additive:

wherein in the formula (1), Q represents an oxygen atom, a methylene group or a single bond; A represents a substituted or unsubstituted alkylene group having 1 to 5 carbon atoms, a carbonyl group, a sulfinyl group, a substituted or unsubstituted fluoroalkylene group having 1 to 6 carbon atoms, or a divalent group having 2 to 6 carbon atoms to which an alkylene unit or a fluoroalkylene unit is bonded through an ether bond; and B represents a substituted or unsubstituted alkylene group, a substituted or unsubstituted fluoroalkylene group or an oxygen atom.

4. The lithium ion battery according to claim 1 , wherein the nonaqueous electrolyte solution comprises a chain sulfonate ester including two sulfonyl groups and being represented by the following formula (2), as the additive:

wherein in the formula (2), X represents an alkylene group having 1 to 6 carbon atoms; and R represents an alkyl group having 1 to 6 carbon atoms, and two Rs may be the same group or different groups.

5. The lithium ion battery according to claim 1 , wherein D 50s /D 50a , being a ratio of an average particle diameter D 50s of the negative electrode active material to an average particle diameter D 50a of the conductive additive, is 3 or higher and 10 or lower.

6. The lithium ion battery according to claim 1 , wherein a content of the conductive additive in a negative electrode mixture of the negative electrode is 2.0 mass % or higher and 10 mass % or lower.

7. The lithium ion battery according to claim 4 , wherein the chain sulfonate represented by the formula (2) is represented by the following formula (3):

8. The lithium ion battery according to claim 1 , wherein a specific surface area of the conductive additive is 10 m 2 /g or larger and 40 m 2 /g or smaller.

9. The lithium ion battery according to claim 1 , wherein the positive electrode active material comprises manganese spinel (LiMn 2 O 4 ).

10. The lithium ion battery according to claim 1 , wherein the positive electrode active material comprises a carbon black.

Assignees

• Azami Takeshi
• Nec Energy Devices Ltd

Inventors

• Azami Takeshi

Classifications

• H01M4/621

  Binders · CPC title

• H01M4/587

  for inserting or intercalating light metals · CPC title

• H01M4/625

  Carbon or graphite · CPC title

• Y02T10/7011

  Cross-Sectional Technologies · mapped topic

• H01M4/133

  Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx · CPC title