Method for evaluating capacity of secondary battery using mathematical calculation of specific resistance components of equivalent circuit model fitted from impedance spectrum
AssigneeKorea Kumho Petrochemical Co., Ltd.
InventorsDong-Hwan Kim, Sang-Hyo Ryu, Hyung-Song Lee
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Abstract
The present invention relates to a method for evaluating an initial capacity of secondary batteries and, more specifically, to a method for evaluating an initial capacity of secondary batteries that involves mathematical operation of specific internal resistance components obtained from an equivalent circuit model of an impedance spectrum measured for a short time period instead of using direct discharge characteristics, thereby allowing selection of batteries having a different initial discharge characteristic.
Claims13
A method for evaluating a capacity of at least one secondary battery, the method comprising:
- (a) preparing the at least one secondary battery to at least one of partially charged to a voltage less than a full charge voltage and partially discharged to a voltage less than the full charge voltage;
- (b) measuring an impedance spectrum for the prepared battery;
- (c) mathematically operating specific internal resistance components obtained from an equivalent circuit model fitted from the impedance spectrum measured;
- and
- (d) comparing the mathematical operation value of the resistance components with an initial discharge capacity graph to evaluate an initial discharge capacity of a unknown battery of the same group.
Dependencies are inferred from the claim text.