SECONDARY BATTERY CAPACITY MEASUREMENT SYSTEM AND SECONDARY BATTERY CAPACITY MEASUREMENT METHOD

摘要

A system for measuring secondary battery capacity includes a data converter, an SOC computer and a maximum capacity computer. The data converter determines a partial differential characteristic curve of capacity-to-voltage differential for the voltage, wherein the partial differential characteristic curve represents a characteristic of the capacity-to-voltage differential based on a history data set of voltage and current values measured in a time marching mode. The SOC computer computes difference between the partial differential characteristic curve and a referential differential curve which represents a referential characteristic of the capacity-to-voltage differential and matches the partial characteristic curve to the referential differential curve by decreasing the difference in order to estimate SOC. The maximum capacity computer estimates a maximum capacity value based on the partial differential characteristic curve and the referential differential curve. The referential differential curve is established with a complex of a first characteristic differential curve and a second characteristic differential curve derived from a positive electrode material and a negative electrode material, respectively.