LITHIUM SECONDARY BATTERY

• US 20110195319A1
• Filed: 02/09/2011
• Published: 08/11/2011
• Est. Priority Date: 02/09/2010
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: INOUE, Ryo, OKUMURA, Takefumi
• Granted Patent: US 8,642,217 B2
• Time in Patent Office: Days
• US Class Current: 429/338
• CPC Class Codes: H01M 10/0525 Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 10/0567 characterised by the additives
• CPC Class Codes: H01M 10/0569 characterised by the solvents
• CPC Class Codes: H01M 2300/0037 Mixture of solvents
• CPC Class Codes: H01M 4/505 of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
• CPC Class Codes: H01M 4/525 of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

The object of the present invention is to provide a lithium secondary battery which can suppress a deterioration for a period of high temperature storage at 50° C. or more.

The present invention relates to a lithium secondary battery comprising a positive electrode which can occlude and discharge lithium ion, a negative electrode which can occlude and discharge lithium ion, a separator which is disposed between the positive electrode and the negative electrode, and an electrolyte, wherein the electrolyte includes a compound within whose molecule a plurality of polymerizable functional groups are included.

Herein, the electrolyte can comprise a compound represented by the formula 3:

wherein each of Z₁ and Z₂ represents a polymerizable functional group including any one selected from the group consisting of allyl group, methallyl group, vinyl group, acryl group and methacryl group.

Claims

1. A lithium secondary battery comprising:

a positive electrode which can occlude and discharge lithium ion;

a negative electrode which can occlude and discharge lithium ion;

a separator which is disposed between said positive electrode and said negative electrode; and

an electrolyte,

wherein said electrolyte comprises a compound within whose molecule a plurality of polymerizable functional groups are included.

2. The lithium secondary battery in claim 1, characterized in that as a positive-electrode active material, said positive electrode comprises a lithium composite oxide represented by the composition formula:

Li_α

Mn_xM1_yM2_zO₂ wherein M1 is at least one selected from the group consisting of Co and Ni;

M2 is at least one selected from the group consisting of Co, Ni, Al, B, Fe, Mg and Cr;

x+y+z=1;

0<

α

<

1.2;

0.2≦

x≦

0.6;

0.2≦

y≦

0.4; and

0.05≦

z≦

0.4.

3. The lithium secondary battery in claim 1, characterized in that as a negative-electrode active material, said negative electrode comprises at least one selected from the group consisting of a carbonaceous material, an oxide including a IV-group element(s), and a nitride including a IV-group element(s).

4. The lithium secondary battery in claim 1, characterized in that as a solvent, said electrolyte comprises

a cyclic carbonate represented by the formula 1:

5. The lithium secondary battery in claim 1, characterized in that as a solvent, said electrolyte comprises dimethallyl carbonate.

6. The lithium secondary battery in claim 4, characterized in that the compound represented by said formula 3 is dimethallyl carbonate.

7. The lithium secondary battery in claim 5, characterized in that an additive amount of said dimethallyl carbonate is in the range of 0.1 to 2.0 vol. %.

8. The lithium secondary battery in claim 6, characterized in that an additive amount of said dimethallyl carbonate is in the range of 0.1 to 2.0 vol. %.