Non-aqueous electrolyte secondary cell with improved safety

• US 8,252,468 B2
• Filed: 07/11/2011
• Issued: 08/28/2012
• Est. Priority Date: 12/28/2007
• Status: Active Grant

• Current Assignee: Panasonic Energy (Shanghai) Co., Ltd. (Panasonic Holdings Corporation)
• Original Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Inventors: Takahashi, Kentaro
• Primary Examiner(s): Ridley, Basia
• Assistant Examiner(s): Leong, Jonathan G
• Application Number:
  US13/179,773
• Publication Number:
  US 20110269028A1
• Time in Patent Office: 414 Days
• Field of Search: 429122-347
• US Class Current: 429/343
• 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 10/4235 Safety or regulating additives or arrangements in electrodes, separators or electrolyte H01M10/4242 takes precedence
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A non-aqueous electrolyte secondary cell is provided having enhanced safety against overcharge and reduced self-discharge. The non-aqueous electrolyte secondary cell includes: a positive electrode having a positive electrode active material; a negative electrode having a negative electrode active material; and a non-aqueous electrolyte containing a non-aqueous solvent and electrolytic salt. The non-aqueous solvent contains 20 to 80 volume % tertiary carboxylic acid ester represented by Formula 2 at 25° C. and 1 atm. The non-aqueous electrolyte contains a halogenated benzene compound.

• • where R1 to R4 each denote a straight-chained or branched alkyl group having 4 or less carbon atoms and may be the same or different.

Claims

1. A non-aqueous electrolyte secondary cell comprising:

a positive electrode having a positive electrode active material;

a negative electrode having a negative electrode active material; and

a non-aqueous electrolyte containing a non-aqueous solvent and electrolytic salt, wherein;

the non-aqueous solvent contains 20 to 80 volume % tertiary carboxylic acid ester at 25°

C. and 1 atm;

the non-aqueous electrolyte contains at least one halogenated benzene compound selected from the group consisting of 3-fluoroanisole and 3,5-difluoroanisole;

the non-aqueous solvent further contains ethylene carbonate;

the tertiary carboxylic acid ester is methyl trimethylacetate and/or ethyl trimethylacetate; and

the content of the halogenated benzene compound is 0.2 to 4.5 mass parts out of 100 mass parts of a total mass of the non-aqueous solvent and the electrolytic salt.