To provide a method of using a lithium secondary battery which is improved in low temperature characteristics of the lithium secondary battery with an iron lithium phosphate compound in a positive electrode and graphite in a negative electrode.
The lithium secondary battery 10 includes a positive electrode sheet 13 formed by forming a positive electrode active material 12 on a collector 11, a negative electrode sheet 18 with a negative electrode active material 17 formed on a surface of a collector 14, and nonaqueous electrolyte liquid 20 filling a gap between the positive electrode sheet 13 and the negative electrode sheet 18. In the lithium secondary battery, an iron lithium phosphate compound is included in the positive electrode active material 12, and graphite and amorphous carbon (for example, graphitized carbon) are included in the negative electrode active material 17. A ratio of amorphous carbon to a total weight of amorphous carbon and graphite is in a range of 20 to 50 wt.%. The lithium secondary battery 10 is used in a predetermined low temperature range so that a usage capacity to a reference capacity which is a battery capacity at 20°C is 70% or more.
COPYRIGHT: (C)2011,JPO&INPIT
Takeshi Sasaki
Osamu Hibida
Mamoru Mizutani
Hiroyuki Nakano
Hiroshi Sawada
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| JP2009032575A |
| WO2009117869A1 |