Method and apparatus for measuring battery capacity

A battery capacity, battery technology, applied in the measurement of electrical variables, measurement of electricity, measurement of current/voltage and other directions, can solve the problem that the measurement efficiency and related accuracy are difficult to achieve excellent, and achieve the effect of less time-consuming

Inactive Publication Date: 2001-07-25
KOREA KUMHO PETROCHEMICAL CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, related art methods using the relationship between battery capacity and impedance at a specific frequency or in a narrow frequency region are difficult to achieve excellent measurement efficiency and related accuracy.

Method used

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  • Method and apparatus for measuring battery capacity
  • Method and apparatus for measuring battery capacity

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0115] Embodiment 1 (comparative example)

[0116] Fabrication of a Fourier transform spectrometer designed to convert, through a 16-bit D / A converter and an electrostatic device (galvanostat), the superposition of multiple sine waves obtained by superimposing the lowest frequency of an odd number of times An input current signal is provided to a battery, and the digital current and voltage signals measured by a two-channel 16-bit A / D converter are sent to a computer, which calculates a complex impedance by using a digital discrete fast Fourier transform algorithm . Here, the pulse current measurement unit is used by storing the pulse input signal to a 16-bit A / D converter.

[0117] Table 1 lists the times required for different measurements of the capacity of a charged battery. In this embodiment, the real-time discharge method, the frequency sweep method performed by selecting a plurality of frequencies at constant intervals in the range of 5mHz to 20KHz, for example, 20, ...

Embodiment 2

[0125] A lithium ion battery (manufactured by Sony Corporation) having a specified capacity of 1300mAh was charged up to a voltage of 4.2V for one hour under room temperature and constant current conditions and fully charged at this voltage for 2.5 hours under constant voltage conditions, Impedance spectra were then measured in the frequency range from 5 mHz to 20 KHz using a Fourier transform impedance spectrometer as described in Example 1.

[0126] To obtain impedance spectra of the same battery under different discharge states, the battery was repeatedly discharged at 130 mAh for 10 hours under constant current conditions and these impedance spectra were continuously measured.

[0127] The impedance spectrum is used with the Figure 4 A composite nonlinear least squares fitting method of the impedance function corresponding to the transmission line equivalent circuit model shown in is fitted to calculate a model parameter, the pseudocapacitance C ps . Comparison of the m...

Embodiment 3

[0130] A lithium-ion battery with an unknown user history and a nominal capacity of 1300mAh was fully charged in the same manner as Example 2. The impedance spectrum is then measured to calculate a model parameter, the charge transfer resistance R et .

[0131]The cells were discharged at a rate of 5 hours at a constant current down to a final voltage of 2.7V at room temperature and the discharge capacity of each cell was calculated. The comparison of the discharge capacity shows the correlation between the model parameters and the discharge capacity, as Figure 8 shown.

[0132] The time required to measure the impedance spectrum for each cell and to calculate the model parameters by approximation does not exceed 420 seconds.

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Abstract

Provided with a method of measuring battery capacity using parameters obtained from a voltage response signal of a current waveform or an impedance spectrum generated thereof where the method includes the steps of: measuring voltage response signals based on a current waveform applied to a primary or secondary battery; obtaining parameters of an equivalent circuit composed of model parameters such as resistors, capacitors and transmission lines either directly from voltage response or after its conversion to frequency dependent impedance; 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.

Description

technical field [0001] The present invention relates to a method and apparatus for determining the capacity of an unknown battery by applying a current or voltage to a primary and secondary cell and by measuring and analyzing an output signal from the applied input signal. More particularly, it relates to a method and apparatus for measuring battery capacity by using parameters obtained from a battery-generated current waveform or a voltage response signal of an impedance spectrum, which method and apparatus provide a non-destructive measure of battery capacity Measurement, used to measure the unknown remaining capacity of a standardized battery product, or, in the case of manufacture, to grade the rated capacity of these batteries. Background technique [0002] Common methods used to measure battery capacity include the real-time discharge method, which is to measure the battery at a constant current I d Discharge time t for power consumption d . [0003] If the capacity...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/36
CPCG01R31/3662G01R31/3651G01R31/3634G01R31/367G01R31/389G01R31/387
Inventor 尹喆五叶夫根·巴苏科夫金钟炫
Owner KOREA KUMHO PETROCHEMICAL CO LTD
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