Korea Kumho Petrochemical Co., Ltd.

Yevgen Barsukov

Jong Hyun Kim

Chul Oh Yoon

Jong-hyun Kim

Chul-Oh Yoon

Hyun-Kyung Sung

Jee-Hwan Jang

A method for selecting unit cells to make an optimal battery pack improves the performance of the battery pack with primary or secondary batteries connected to one another in series, in parallel, or in a combination of them. The method for selecting unit cells to make the optimal battery pack includes measuring the impedance spectrum of the individual unit cells in a predetermined frequency region, fitting the impedance spectrum to an equivalent circuit model composed of parameters including resistance and capacitance components, calculating total resistances from the fitted parameters, and making the battery pack with unit cells of a similar total resistance.

Method of grouping single cells of power sources to build optimal packs using parameters obtained by analysis of impedance spectrum

A method of measuring impedance is based on carrier function Laplace transform. The measurement includes detecting a response signal from a device under test, to which signal an excitation such as a pulse, interrupt or constant load is applied. Resulting data is fitted to a carrier function, selected so as to be capable of providing a good fit and for which an analytical Laplace transform is known, in order to obtain parameters of such function providing best fit. Obtained parameters are further substituted into the analytical expression of Laplace transform of carrier function which is used to calculate a frequency dependent impedance function in the Laplace domain. The resulting impedance function is used for calculating the impedance spectrum in a frequency domain and for calculating the measurement error of the frequency domain impedance spectrum using the standard deviations of the parameters, obtained during fitting of time-domain data.

Laplace transform impedance spectrometer and its measurement method

Provided with a method of measuring battery capacity by impedance spectrum analysis, which is to measure a characteristic impedance spectrum of primary and secondary batteries and determine the battery capacity the method including the steps of: (1) measuring the characteristic impedance spectrum of a battery in a predetermined frequency region; (2) determining a parameter from the measured impedance spectrum; (3) monitoring in advance the correlation between the determined parameter and the battery capacity measured by a real-time discharge technique; and (4) determining the battery capacity from the characteristic impedance spectrum of a battery having an unknown capacity based on the monitored correlation.

Method of and apparatus for measuring battery capacity by impedance spectrum analysis

A method and an apparatus for determining characteristic parameters of a charge storage device based on a wide frequency range of impedance measurement and a non-linear equivalent circuit model by which the parameters of the non-linear equivalent circuit model indicative of the characteristics of various charge storage devices such as a primary battery, secondary battery, capacitor, supercapacitor and fuel cell are determined, the method comprising the steps of: (1) measuring voltage and current characteristics in a process of charging/discharging of the charge storage device by applying a voltage/current at a predetermined discharge rate; (2) measuring impedance spectra at a predetermined range of frequency by measuring the current and voltage from both terminals of the charge storage device or from an electrical load directly connected to the charge storage device at a plurality of states of charge within the entire charge/discharge interval; and (3) obtaining the parameters of the non-linear equivalent circuit of the charge storage device from the charge or discharge characteristics measured in step (1) and the characteristic impedance spectrum in the predetermined range of frequency measured in step (2).

Method and apparatus for determining Characteristic parameters of a

A method of measuring battery capacity using a voltage response signal based on a pulse current, where the method includes the steps of: measuring a voltage response signal based on a pulse current signal applied to a primary or secondary battery; performing an approximation of the measured voltage response signal to an equivalent circuit model composed of resistors, capacitors and transmission lines to determine the model parameters; and determining the unknown battery capacity from the voltage response characteristics based on a correlation between the measured capacity and the model parameters, which correlation is previously determined by a real-time discharge method, thereby takes a shorter time than a real-time discharge method and delivering efficiency and reliability in determining model parameters of an equivalent circuit which are in close correlation with the charge/discharge condition of the battery.

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Taejeon, South Korea

Yevgen Barsukov