NON-AQUEOUS ELECTROLYTE SECONDARY CELL AND ITS CHARGING METHOD

摘要

A non-aqueous electrolyte secondary cell is characterized in that the negative plate is made chiefly of composite particles of which at least part of the core particles containing at least one kind among tin, silicon, and zinc as a constituent element are coated with a solid solution or an intermetallic compound consisting of the constituent element constituting the core particles and at least one element selected from the group consisting of Group 2 elements of the periodic table except the constituent element, transition elements, Group 12 elements, Group 13 elements, and Group 14 elements except carbon and in that the content of lithium in the core particles of the composite particles lies in the range from 50 element% to 90 element% of the theoretical limit of the lithium content. The secondary cell is further characterized in that it is charged with, first, a constant current and then with a low voltage after the voltage reaches a preset voltage, and the current density in charging is controlled. Therefore, the non-aqueous electrolyte secondary cell has a high energy density, and excellent cycle life characteristics.