The present disclosure relates to a battery and a negative electrode for battery. In addition, the present disclosure relates to a battery pack using a battery, an electronic apparatus, an electric vehicle, an electricity storage apparatus, and an electric power system.
In recent years, with the spread of portable electronic information apparatuses such as mobile phones, video cameras, laptop personal computers, and the like, high performance, miniaturization, and reduction in weight of these apparatuses have been achieved. As a power source of the apparatus, a disposable primary battery or a reusable secondary battery is used, but demand for a nonaqueous electrolyte battery, particularly, a lithium ion secondary battery has increased because of its good overall balance of performance, size, weight, cost, and the like. In addition, as further high-performance, miniaturization, or the like of such an apparatus is progressively achieved, new high-energy density is desired even with respect to the nonaqueous electrolyte battery such as the lithium ion secondary battery.
In the secondary battery represented by the lithium ion secondary battery, a graphite material is widely used as a negative electrode active material, and because of demands for high capacity, among the graphite materials natural graphite having a large theoretical capacity or artificial graphite having the same form as the natural graphite may be used.
In Japanese Unexamined Patent Application Publication No. 8-180869, upon using fibrous carbon as the negative electrode active material, there is described a method of using an electrode for solving defects of structural anisotropy being strong due to the significantly high orientation, and a capacity does not increase due to different likelihood of intercalation depending on the direction. Specifically, a method in which a carbonaceous material having an average length not more than 5 mm that is obtainable from a carbon body having the orientation P of 70%≦P≦85% and a crystallite thickness Lc by X-ray diffraction of 13 Å≦Lc≦20 Å may be used to provide a secondary battery electrode is described. Thus, a secondary battery having a high capacity may be realized.
In Japanese Unexamined Patent Application Publication No. 2006-286427, there is described an electrode plate for nonaqueous electrolyte secondary battery that includes two or more electrode active material layers and one or more conductive layers in at least one surface of a collector, and has a laminated structure capable of charging and discharging which is constructed by alternately laminating the electrode active material layer and the conductive layer. In the electrode plate for the nonaqueous electrolyte secondary battery, each conductive layer is an ion permeable porous matter with voids, and is directly conducted with or indirectly conducted with the collector via the other conductive layer. Accordingly, the amount of active material per unit area of the electrode may be increased without decreasing output characteristics, and a weight energy density and a volume energy density of the electrode plate may be improved. Therefore, it is possible to reduce the number of collector and separator, thereby reducing material costs.
In Japanese Unexamined Patent Application Publication No. 2003-68301, there is described a method of using a negative electrode that includes a negative electrode mixture layer containing graphite particles whose average roundness is at least 0.93 as a negative electrode active material and the other graphite particles in order to solve a problem that load characteristics of the battery is deteriorated when using scale-like graphite particles. There is described a method of providing the nonaqueous electrolyte secondary battery having excellent load characteristics in which an orientation degree of the graphite particles by X-ray diffraction of the negative electrode mixture layer is at least 0.001.
In addition, in Japanese Unexamined Patent Application Publication No. 2009-238584, there is described a negative electrode using carbon particles having a roundness of a particle cross section of 0.6 to 0.9, an interlayer distance d (002) of graphite crystal found by X-ray diffraction measurement of 3.38 Å or less, and a crystallite size Lc (002) in a C-axis direction of 500 Å or more. In Japanese Unexamined Patent Application Publication No. 2009-238584, there is described a method of using, in the negative electrode, carbon particles in which a peak intensity ratio of a carbon 002 face and a carbon 110 face measured by the X-ray diffraction is 600 or less to thereby obtain a battery of high capacity and excellent cycle characteristics.
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