# US 8,785,015 B2 · Additives for non-aqueous electrolyte and secondary battery using the same

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- Number: US 8,785,015 B2
- Document ID: US8785015B2
- Status: Granted
- Kind: B2
- Application number: 12/600,070
- Filed: 2008-05-15
- Published: 2010-11-25
- Granted: 2014-07-22
- Earliest claimed: 2007-05-15
- Assignees: LG Chem, Ltd.
- Applicants: Mi Young Son; Jeong-Ju Cho; Hochun Lee; Joomi Jeon; Sunghoon Yu
- Inventors: Mi Young Son; Jeong-Ju Cho; Hochun Lee; Joomi Jeon; Sunghoon Yu
- Web page: https://patentgrep.com/patent/US8785015B2

## CPC

- H01M 10/0567: characterised by the additives
- H01M 10/052: Li-accumulators
- H01M 10/4235: {Safety or regulating additives or arrangements in electrodes, separators or electrolyte (H01M10/4242 takes precedence)}
- H01M 10/44: Methods for charging or discharging (circuits for charging H02J7/00)
- H01M 10/48: Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte (constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569)
- H01M 10/486: {for measuring temperature}
- H01M 50/30: Arrangements for facilitating escape of gases
- Y02E 60/10: Energy storage using batteries
- Y02T 10/70: Energy storage systems for electromobility, e.g. batteries
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

Disclosed are an electrolyte for a secondary battery, and a secondary battery including the same, the electrolyte including an electrolyte salt; an electrolyte solvent; and a compound generating heat through oxidation at voltages higher than drive voltage of a cathode, wherein the compound can decompose or evaporate electrolyte components by oxidation heat, thereby causing gas generation. Also, the compound is included in an internal pressure increase accelerant for a battery. Upon overcharge, since a compound subjected to oxidation at voltages higher than normal drive voltage of a cathode generates heat, electrolyte components can be decomposed or evaporated, thereby generating gas by the oxidation heat. Accordingly, it is possible to operate a safety means of a battery, without using an internal pressure increasing material directly generating gas through oxidation at overcharge voltage as the electrolyte additive, and thus to improve the overcharge safety of a secondary battery.

## Claims

### Claim 1

An electrolyte for a secondary battery comprising: (a) an electrolyte salt; (b) an electrolyte solvent comprising fluoroethylene carbonate, propylene carbonate and dimethyl carbonate; and (c) a compound generating heat through oxidation at voltages higher than drive voltage of a cathode,
wherein the compound is 5,6,7,8-tetrafluorobenzo-1,4-dioxane, and
wherein the compound decomposes or evaporates electrolyte components by oxidation heat, thereby causing generation of gas.

### Claim 2 (depends on 1)

The electrolyte of claim 1, wherein an amount of the heat generated by the oxidation of the compound (c) is equal to or more than a range where the electrolyte components are decomposed or evaporated, and is less than a range where structural breakdown of a cathode active material is caused.

### Claim 3 (depends on 1)

The electrolyte of claim 1, wherein the compound (c) is a compound subjected to a reversible redox shuttle reaction.

### Claim 4 (depends on 3)

The electrolyte of claim 3, wherein the compound subjected to the reversible redox shuttle reaction generates heat at both oxidation and reduction.

### Claim 5 (depends on 1)

The electrolyte of claim 1, wherein a content of the compound (c) is within a range of 0.05 to 5 parts by weight, based on 100 parts by weight of the electrolyte.

### Claim 6 (depends on 1)

A secondary battery comprising a cathode; an anode; and the electrolyte of claim 1.

### Claim 7 (depends on 6)

The secondary battery of claim 6, wherein charge voltage is up to 4.35V.

### Claim 8 (depends on 6)

The secondary battery of claim 6, which is a lithium secondary battery.

### Claim 9 (depends on 1)

The electrolyte of claim 1, wherein a content of the compound (c) is within a range of 0.1 to 3 parts by weight, based on 100 parts by weight of the electrolyte.