Active material, nonaqueous electrolyte battery, battery pack and battery module
摘要
說明書
The composite oxide contained in the active material for a battery according to the first embodiment may be in the state of, for example, a particle. An average particle size of the composite oxide contained in the active material for a battery according to the first embodiment is not particularly limited, and may be varied depending on the desired battery characteristic.
It is preferable that the active material for a battery according to the first embodiment contains the composite oxide particles described above, and a conductive substance such as carbon with which the surface of the particles is covered. The active material for a battery according to such a preferable aspect can exhibit an improved quick charge-and-discharge performance. In the composite oxide described above, the lithium is inserted and extracted via a homogeneous solid state reaction, and thus the composite oxide has a nature in which the higher the lithium insertion amount, the higher the electrical conductivity. In such a composite oxide, the electrical conductivity is relatively reduced in a region where the lithium insertion amount is small. When the surface of the composite oxide particle is previously coated with a conductive substance such as carbon, accordingly, the high quick-charge-and-discharge performance can be obtained regardless of the lithium insertion amount.
Alternatively, the same effects as above can be obtained by coating the surface of the composite oxide particles with lithium titanate, which expresses electrical conductivity with the lithium insertion, instead of the conductive substance such as carbon. In addition, since lithium titanate with which the surface of the composite oxide particles is covered exhibit an insulation property by the extraction of lithium when the battery is internally short-circuited, the lithium titanate can exhibit excellent safety.
