Lithium ion secondary battery

Patent metadata

Field	Value
Publication number	US-10923770-B2
Application number	US-201716465428-A
Country	US
Kind code	B2
Filing date	Nov 30, 2017
Priority date	Dec 2, 2016
Publication date	Feb 16, 2021
Grant date	Feb 16, 2021

Abstract

A purpose of one embodiment of the present invention is to provide a lithium ion secondary battery that has improved life-span characteristics. The first lithium ion secondary battery of the present invention comprises an electrolyte solution comprising a sulfone compound, a fluorinated ether compound and LiN(FSO 2 ) 2 , and a negative electrode comprising a silicon material, wherein a content of LiN(FSO 2 ) 2 in the electrolyte solution is more than 5 weight % and 20 weight % or less.

First claim

The invention claimed is:

1. A lithium ion secondary battery comprising an electrolyte solution comprising a sulfone compound represented by formula (1), a fluorinated ether compound represented by formula (2) and LiN(FSO 2 ) 2 , and a negative electrode comprising a silicon material, wherein a content of LiN(FSO 2 ) 2 in the electrolyte solution is more than 5 weight % and 20 weight % or less,
R 1 ″—SO 2 —R 2 ″  (1)

wherein R 1 ″ and R 2 ″ are each independently a substituted or unsubstituted alkyl group or alkylene group, and in the case of the alkylene group, R 1 ″ and R 2 ″ are bonded via a single bond or a double bond to form a ring,
R 1 —O—R 2   (2)

wherein R 1 and R 2 are each independently an alkyl group, and at least one of R 1 and R 2 is a fluorine-containing alkyl group.

2. The lithium ion secondary battery according to claim 1 , wherein the electrolyte solution comprises LiPF 6 .

3. The lithium ion secondary battery according to claim 2 , wherein a ratio of LiN(FSO 2 ) 2 with respect to a total amount of LiPF 6 and LiN(FSO 2 ) 2 is 10 mol % or more and 90 mol % or less.

4. The lithium ion secondary battery according to claim 1 , wherein the lithium ion secondary battery comprises a positive electrode comprising a layered lithium oxide represented by formula (3) or formula (4),
Li y Ni 1-x M x O 2   (3)

wherein 0≤x≤0.8, 0<y≤1.2 and M is at least one element selected from the group consisting of Co, Al, Mn, Fe, Ti and B,
Li(Li x M 1-x-z Mn z )O 2   (4)

wherein 0.1≤x<0.3, 0.33≤z≤0.8, and M is at least one of Fe, Co, Ni, Ti, Al and Mg.

5. The lithium ion secondary battery according to claim 1 , wherein a content of the fluorinated ether compound in the electrolyte solution is 20 weight % or more and 80 weight % or less.

6. The lithium ion secondary battery according to claim 1 , wherein a content of the sulfone compound in the electrolyte solution is 15 weight % or more and 70 weight % or less.

7. The lithium ion secondary battery according to claim 1 , wherein the silicon material is an alloy comprising silicon or a silicon oxide.

8. The lithium ion secondary battery according to claim 1 , wherein the sulfone compound is at least one selected from sulfolane, 3-methylsulfolane, dimethyl sulfone, ethyl methyl sulfone, diethyl sulfone, methyl isopropyl sulfone, and ethyl isopropyl sulfone.

9. A vehicle equipped with the lithium ion secondary battery according to claim 1 .

10. A method for manufacturing a lithium ion secondary battery, comprising the steps of:
fabricating an electrode element by stacking a positive electrode and a negative electrode via a separator, and
encapsulating the electrode element and an electrolyte solution into an outer package,
wherein the electrolyte solution comprises a sulfone compound represented by formula (1), a fluorinated ether compound represented by formula (2) and LiN(FSO 2 ) 2 , wherein a content of LiN(FSO 2 ) 2 in the electrolyte solution is more than 5 weight % and 20 weight % or less, and the negative electrode comprises a silicon material,
R 1 ″—SO 2 —R 2 ″  (1)

wherein R 1 ″ and R 2 ″ are each independently a substituted or unsubstituted alkyl group or alkylene group, and in the case of the alkylene group, R 1 ″ and R 2 ″ are bonded via a single bond or a double bond to form a ring,
R 1 —O—R 2   (2)

wherein R 1 and R 2 are each independently an alkyl group, and at least one of R 1 and R 2 is a fluorine-containing alkyl group.

Assignees

• Nec Corp

Inventors

• Noguchi Takehiro
• Hasegawa Takuya
• Kawasaki Daisuke
• Shimanuki Ikiko

Classifications

• Y02E60/10

  Energy storage using batteries · CPC title

• H01M4/134

  Electrodes based on metals, Si or alloys · CPC title

• H01M10/0569 Primary

  characterised by the solvents · CPC title

• H01M4/386 Primary

  Silicon or alloys based on silicon · CPC title

• H01M10/0568

  characterised by the solutes · CPC title