Nonaqueous electrolyte secondary battery and method for manufacturing negative electrode of the same
US6455199B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 22, 1999 |
| Grant date | Sep 24, 2002 |
| Priority date | — |
| Expiry date | Feb 22, 2019 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T29/49108
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
Graphite powder for a negative electrode in prior arts, which allows lithium ions to repeat intercalation and deintercalation reversibly by charge and discharge, has failed to attain a specific capacity close to the theoretical capacity of 372 mAh per 1 g. Also, there was a problem in storage property at a high temperature when it is attempted to improve the high rate charge and discharge characteristics. An object of the present invention is to solve these problems. In the process of pulverizing flaky graphite particles of which plane interval (d002) of (002) plane is 3.350 to 3.360 angstroms, and crystallite size (Lc) in the C-axis direction is at least 1000 angstroms or more, the graphite particles are chamfered into disk- or tablet-like form, which are then sifted, so as to obtain a graphite powder, of which mean particle size is defined within the range of 10 to 30 microns, mean thickness of thinnest portion is defined to be 3 to 9 microns, and X-ray diffraction peak intensity ratio of (110)/(004) by a wide angle X-ray diffraction method is defined to be 0.015 or more. By using this powder, the conventional problems are solved in a favorable balance, and, while achieving high …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.