摘要:
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 energy density, the high rate discharge performance and reliability when left at a high temperature can be enhanced.
摘要:
Enhancement of the storage property at a high temperature and discharge characteristics at a low temperature of a nonaqueous electrolyte secondary cell is intended. A negative electrode material which is prepared by covering the surface of a nucleus made of a graphite powder with a carbonaceous matter, the graphite powder having a specified plane interval, spectrum value, mean particle size, specific surface area, tapping density, and (110)/(004) X-ray peak intensity ratio, is used in the nonaqueous electrolyte secondary cell.
摘要:
Enhancement of the storage property at a high temperature and discharge characteristics at a low temperature of a nonaqueous electrolyte secondary cell is intended. A negative electrode material which is prepared by covering the surface of a nucleus made of a graphite powder with a carbonaceous matter, the graphite powder having a specified plane interval, spectrum value, mean particle size, specific surface area, tapping density, and (110)/(004) X-ray peak intensity ratio, is used in the nonaqueous electrolyte secondary cell.
摘要:
The present invention relates to a lithium ion secondary battery using as the negative active material thereof a carbon material that enables the absorption and release of lithium ions and has volume resistivity not exceeding 5.0×10−3 ohmcm, thereby preventing battery temperatures from increasing abruptly due to low volume resistivity of the carbon material even when short-circuiting takes place inside of the battery.
摘要:
The present invention relates to a nonaqueous electrolyte secondary battery, and more particularly to its separator, and it is an object thereof to prevent electrolyte leakage accident due to elevation of cell internal pressure even if the cell is exposed to high temperature without sacrificing the cell capacity. To achieve the object, by using the polyolefin group separator large in endothermic calorie per unit area by the heat of fusion in a temperature range of 70 to 150° C., and selecting appropriate graphite powder for negative electrode and organic solvent in nonaqueous electrolyte, the electrolyte leakage accident can be successfully eliminated by suppressing the reaction between the cell active substance and organic solvent, thereby suppressing elevation of cell internal pressure.
摘要:
A non-aqueous secondary battery having an electrode group comprising a portion of exposed metal foil electrically connected to the positive electrode collector and covering the entire outer surface of the electrode group. Separator material is sandwiched between the foil and the negative electrode, which is positioned outwardly of the positive electrode, and separator material is also positioned between the foil covering of the electrode group and a negative polarity cell container. The positioning of the metal foil is such that if the battery is crushed, the separator material on the outermost side of the metal foil or between the metal foil and the negative electrode is broken first, so that the metal foil short-circuits with the inner wall of the cell container or the negative electrode, respectively.
摘要:
A cell capable of preventing precipitation of lithium on a negative electrode plate in the final stage of a cycle life and achieving a superior cycling performance and high safety and reliability is provided. In a rechargeable secondary cell using a non-aqueous electrolyte, a positive electrode contains an active material and a conductive element, and Ketjenblack, a mixture of Ketjenblack and flake graphite or a mixture of Ketjenblack and acetylene black is employed as such conductive element.
摘要:
A non-aqueous secondary battery having an electrode group comprising a portion of exposed metal foil electrically connected to the positive electrode collector and covering the entire outer surface of the electrode group. Separator material is sandwiched between the foil and the negative electrode, which is positioned outwardly of the positive electrode, and separator material is also positioned between the foil covering of the electrode group and a negative polarity cell container. The positioning of the metal foil is such that if the battery is crushed, the separator material on the outermost side of the metal foil or between the metal foil and the negative electrode is broken first, so that the metal foil short-circuits with the inner wall of the cell container or the negative electrode, respectively.
摘要:
Electrodes of a chip coil are provided at no magnetic flux concentrated positions of a core of the chip coil. In other words, the chip coil has a configuration where: lead frames are provided at the center of the length of both brims of the core; conductive parts and the ends of a conductive wire are connected to internal electrodes, which are made of thin metal films and provided on both brims, respectively; and external electrodes are extended so as to protrude from the sides of a core drum. This reduces magnetic loss and prevents deterioration of characteristics and the Q value due to the electrodes.
摘要:
A scanning electron microscope includes a heater coil which is arranged around a sample, an electron beam which is radiated when the sample is heated, and a secondary electron generated from the sample which is attracted to a photo multiplier. In this electron microscope, a shield plate is provided having an extracting hole for extracting the secondary electron outside of the heat coil in such a manner that the extracting hole is aligned with a light axis of the electron beam. The shield plate is connected to a power source which supplies a variable voltage so that a desired voltage can be applied to the shield plate so as to shield thermal electrons.