KR200313039Y1 - Portable battery-pack non-destructive test system using AC impedance measurement technology and multi-channel measurement system which it use - Google Patents

Abstract

The present invention shortens the time required to measure the characteristics of the battery, increases the reliability of the measurement results, enables the analysis of measurement errors, and the configuration of the measurement system to simplify the multi-channel and miniaturization of measurement equipment. In addition, since the DC signal is measured and numerically processed in the process of acquiring the AC impedance spectrum, the structure of the actual measuring device is based on the DC device, so it can be easily combined with the existing DC charging / discharging test device. The precise analysis of these components provides useful information about the kinetic properties of the constituent materials, including data on the behavior of important kinetic properties such as surface reaction resistance, diffusion coefficient, electrolyte average resistance, and conductivity distribution resistance of the particles. This result is not only related to the mixed composition of materials, but also to the temperature characteristics, deterioration characteristics and reaction stability of the battery. Portable battery pack using AC impedance measurement technology that can provide useful information at the design stage of the battery cell by detecting the error of the circuit of the battery cell itself. A non-destructive evaluation device and a multi-channel measurement system using the same.

Description

Portable battery-pack non-destructive test system using AC impedance measurement technology and multi-channel measurement system which it use}

The present invention relates to a portable battery pack non-destructive evaluation device using the AC impedance measurement technology and a multi-channel measurement system using the same, and more specifically, the battery such as open circuit voltage, internal resistance, charge and discharge voltage, temperature characteristics of the battery It is for evaluating the intrinsic and nonlinear driving characteristics.It shortens the time required to measure the characteristics of the battery, increases the reliability of the measurement results, enables analysis of measurement errors, and makes the measurement system simple to measure. Multi-channel and miniaturization of the equipment is possible, and the measurement of DC signal is performed numerically in the process of acquiring the AC impedance spectrum, so the structure of the actual measuring device is based on the DC device. Can be combined, and the precise analysis of the characteristics of the battery etic) Data on the behavior of important kinetic properties such as surface reaction resistance, diffusion coefficient, electrolyte average resistance, and conductivity distribution resistance of the particles can be obtained. Rather, it will provide critical information about the temperature characteristics, deterioration characteristics, and reaction stability of the battery, so that it can be usefully used in the design stage of the battery.

In general, the driving characteristics of a battery are determined by the thermodynamic and kinetic properties of the constituent material and its composition, which generally exhibits non-linear behavior and thus is not easy to systematically evaluate.

In addition, since the battery production takes several hours in capacity evaluation and recharging by real-time discharge in the product sorting process, the investment cost for the multi-channel sorter occupies a substantial portion of the total facility investment required for battery manufacturing.

In addition, the AC characteristic frequency range of an electrochemical system including a storage battery generally ranges from several mHz to several tens of kHz, which is determined by a time constant of a kinetic process such as electrochemical reaction or diffusion at an interface.

By means of small voltage approximation, each electrochemical process can be explained from the characteristic factors of the circuit, such as the resistor and the capacitor, which constitute the impedance of the equivalent circuit in the frequency space. It can be determined by approximating the impedance spectrum experimentally obtained at the state of charge.

When the parameterization of the characteristic factor is carried out experimentally in each state of charge and discharge of the battery, and the electromotive force (open circuit voltage) of the battery in the steady state is measured, these results are numerical images representing the characteristics of the battery numerically. image) can be used for the precise analysis of the characteristic factors related to the driving characteristics of the battery and for the simulation of battery driving characteristics under any electrical load conditions.

Some characteristic factors of the nonlinear circuit model show interdependence on the state of charge and discharge of the battery, which can be used to predict the capacity of the battery.

Conventional impedance spectrum measurement method is to apply a periodic excitation signal of a constant frequency, and to measure the spectrum with a phase sensing device such as a frequency response analyzer (FRA), but the measurement method as described above is a signal generator and phase detector It is necessary to use expensive equipment such as an electronic device, and at least two cycles of signals are needed to eliminate the transient effects. In addition, when the spectrum of multiple frequencies is needed, the measurement is performed sequentially. There is a problem that becomes longer.

When using the measurement method of fast Fourier transform (FFT) the response signal using multiple superimposed sinusoids as an excitation signal, the time required for spectrum measurement for multiple frequencies is not included in the method using the frequency response analyzer. Shorter than

However, the fast Fourier transform method requires more than twice the measurement time of the lowest frequency period for the frequency domain to be measured, requires a complex signal generator and a large-capacity memory, and the applied perturbation signal is incoherent. Because of the superposition of these signals, impedance at a frequency corresponding to an odd multiple of the lowest frequency is obtained, thereby reducing the resolution of the impedance data in the low frequency region.

In addition, there is a method of using a pulse current instead of a plurality of superimposed sine waves, but in this case, the noise is too severe due to frequency aliasing and transient effects, which are not eliminated by repeated measurement and averaging method, and cause measurement error. There is a problem that it is difficult to determine the reliability or to set the confidence interval.

Accordingly, an object of the present invention is to solve the conventional problems as described above, and measures various electrochemical devices such as various electric circuits, linear devices, nonlinear devices, capacitors, primary cells, secondary batteries, fuel cells, and the like. A high quality wide impedance spectrum can be measured from the system targeted at the minimum time theoretically possible. Especially, the portable battery pack nondestructive evaluation using AC impedance measurement technology with high accuracy, fast measurement speed and simple measurement device An apparatus and a multichannel measurement system using the same are provided.

In addition, another object of the present invention is that the size of the memory required for the operation is small, the linearity of the specific system can be evaluated, and the confidence interval is set in the frequency domain measurement value in analyzing the quality of the measurement and the linearity of the measurement system. The present invention provides a portable battery pack nondestructive evaluation device using AC impedance measurement technology to obtain standard statistical means, and a multi-channel measurement system using the same.

1 is a block diagram of a non-destructive evaluation device for a portable battery pack using the alternating current impedance measurement technology according to the present invention.

Figure 2 is a block diagram of a multi-channel measurement system using a portable battery pack non-destructive evaluation device according to the present invention.

Explanation of symbols on the main parts of the drawings

1: processing device 2: output device

3: bandwidth controller 4: detection device

5: inverter 6: power amplifier

7: Remote control device 21: AC generator

22: attenuator 25: mixer

26: bias supply 27: slope limiter

41: voltage detector 46: current detector

51: voltage compensation DAC 51 ': current compensation DAC

52, 52 ': mixer 53, 53': amplifier

54, 54 ': low pass filter 55: voltage ADC

55 ': current ADC

Portable battery pack non-destructive evaluation device using the AC impedance measurement technology according to the present invention for achieving the above object, select the applied signal required for the measurement, and provides a voltage and current compensation signal according to the internal error of the system, A processing device that calculates data on driving characteristics of the battery by analyzing the measurement result signal, a detecting device which detects voltage and current output from the battery and removes a DC bias component and a noise component, and an applied signal selected by the processing device An output device for outputting a signal, a bandwidth controller for compensating for the signal detected by the detection device and limiting or blocking the bandwidth of the signal output from the output device, and amplifying the signal compensated by the controller to continuously apply constant voltage or constant current to the battery. A power amplifier to be applied by the detector and the detection device And asynchronous FIFO / gain and offset error compensator for compensating the compensation signal provided from the processing device to output the measured signal and outputting the measurement result signal to facilitate high-speed transmission of data and correct for gain and offset errors.

Hereinafter, with reference to the accompanying drawings a preferred embodiment of the present invention to be described in detail.

1 is a block diagram of a portable battery pack non-destructive evaluation device using the AC impedance measurement technology according to the present invention and a multi-channel measurement system using the same, which is applied to the storage battery B for measuring driving characteristics in the processing apparatus 1. The output of the applied signal output from the output device 2 is controlled by selecting the magnitude of the applied signal, for example, a sine signal, a pulse signal, a step signal, and the like.

At this time, the signal output from the processing device 1 is applied to the output device 2 via the asynchronous FIFO / gain and offset error corrector 8, and the asynchronous FIFO / gain and offset error corrector 8 is It facilitates high speed transmission and compensates for gain and offset errors.

By the control of the processing device 1, the AC generator 21 of the output device 2 generates an AC component of the applied signal, and the bias supply 26 generates a DC component of the applied signal.

At this time, the peak to peak (PP) voltage of the AC component generated by the AC generator 21 is in the unit of several tens of kHz and needs to be attenuated if necessary, and thus passes through the attenuator 22 for attenuating the PP voltage.

In addition, the DC component generated by the bias supply 26 is to set the virtual operating point of the battery B or to set the DC offset to '0', and to oscillate during the settling time. As a result, a slope limiter 27 is removed to remove this portion.

The AC component and the DC component passing through the attenuator 22 and the slope limiter 27 are synthesized by the adder 25 to output an application signal including the AC component and the DC component.

The application signal output from the adder 25 is input to the bandwidth controller 3, and the bandwidth controller 3 receives the detection signal of the voltage and current detected by the detection device 4 to compensate for the application signal. In order to ensure stable operation from overload, the bandwidth is limited or blocked.

The applied signal compensated by the bandwidth controller 3 is amplified by the power amplifier 6 for continuously applying the constant voltage or the constant current and is applied to the battery B. At this time, the voltage and the current of the battery B formed are detected. Detected by the voltage detector 41 and the current detector 46 of the device 4, the current detected by the current detector 46 is converted into a voltage in the current / voltage converter 47.

Here, the detection device 4 removes the DC bias voltage, the current component and the noise component to detect only an AC input.

The voltage and current detected by the detection device 4 are converted into a digital signal via the converter 5, and then through the asynchronous FIFO / gain and offset error corrector 8 '. The processing apparatus 1 calculates driving characteristic data of the storage battery B based on the application signal and the detection signal.

The processing apparatus 1 approximates the digital voltage and current with a fast Fourier transform or Laplace transform median function, generates an impedance spectrum, and analyzes and stores the calculation result.

Here, the high speed processing is possible by the asynchronous FIFO / gain and offset error corrector 8 (8 '), so that the measurement range can be sufficiently extended.

In addition, the converter 5 receives voltage and current compensation data according to an error (noise, attenuation, etc.) in the system from the processor 1, and performs a DC bias voltage compensation digital to analog converter (DAC) 51. And a DC bias current compensation DAC 51 'to an analog signal, and the converted voltage and current compensation data are detected by the detection device 4 and the adder 52 ( 52 ').

At this time, a compensation signal for the measurement error and leakage is output from the gain and offset error compensators 56 and 56 'and input to the DC bias voltage compensation DAC 51 and the DC bias current compensation DAC 51'.

The synthesized signal from the adders 52 and 52 'is amplified by the amplifiers 53 and 53' and then filtered by the low pass filters 54 and 54 'to remove high frequency components. The signal is converted into a digital signal from a voltage ADC (Analog to Digital Converter) 55 and a current ADC 55 'and input to the processing apparatus 1.

In addition, the application signal applied from the processing device 1, the compensation signal and the data calculation method according to the measurement result, etc. can be stored in the processing device 1, and a separate output device is provided with various input signals and The analysis result can be displayed and the desired one can be selected by the remote control device 7 as necessary.

2 is a block diagram of a multi-channel measurement system using a portable battery pack non-destructive evaluation device according to the present invention, the multi-measurement device 9 for measuring a plurality of batteries (B) is an output device (2), bandwidth controller (3), a plurality of single modules (M) consisting of a detection device (4), a converter (5) and a power amplifier (6) is mounted, and the data received from the asynchronous FIFO / gain and offset error corrector (8) And a switching device 91 which transmits to the single module M, respectively, and transmits the output signal of each single module M to the asynchronous FIFO / gain and offset error corrector 8 '.

Measure the characteristic impedance spectra of primary and secondary batteries in a wide frequency range from low frequency in the uHz band to high frequency in the MHz band, and measure the measured characteristic impedance spectrum in an equivalent circuit composed of model constants such as resistance, storage battery and transmission line. By approximating the value of the model constant, the capacity of the battery is measured by characteristic impedance spectrum analysis of a battery having an unknown battery capacity based on the correlation between the capacity of the battery previously investigated by the real time discharge method and the model constant.

Compared to the real-time discharge method, the measurement time is shorter and the model constant of the equivalent circuit having a precise correlation with the state of charge and discharge is used.In this case, the correlation between the internal impedance value of the battery and the battery capacity is used as a chemical used as the active material of the battery. Since it is determined by the impedance response characteristics of the material, the efficiency and reliability of determining the model constant by analyzing the impedance spectrum of a wide frequency range is excellent, and it is possible to check the failure of the cell itself by detecting an error in the circuit of the battery cell itself. Do.

Although the present invention has been described with respect to the measurement of the impedance of the storage battery (B), it is applicable to all electrochemical devices, various modifications are possible within the scope without departing from the basic concept according to the needs of those skilled in the art.

As described above, according to the present invention, the Laplace transform method (CFLT) using a carrier function has excellent measurement accuracy and a measurement time of 1 / F of the FFT without using a signal generator used in a multi-wave FFT. Since it is shortened to 2 and the numerical process is performed by measuring the DC signal in the process of acquiring the AC impedance spectrum, the structure of the actual measuring device is based on the DC device and can be easily combined with the existing DC charge / discharge test device.

In addition, the detailed analysis of the battery's characteristic factors can provide useful information on the kinetic properties of the constituent materials, which can be used to determine the behavior of important kinetic properties such as surface response resistance, diffusion coefficient, electrolyte average resistance, and conductivity distribution resistance. The results will provide critical information on the temperature, degradation, and reaction stability of the battery as well as the mixed composition of materials. It is possible to check whether there is a failure and to be useful in the design stage of the actual battery.

Claims (6)

In the apparatus for measuring the drive characteristics of the storage battery (B), A processing device 1 for selecting an applied signal required for measurement, providing a voltage and current compensation signal according to an internal error of the system, and analyzing the measurement result signal accordingly to calculate data on driving characteristics of the storage battery B; , A detection device 4 for detecting a voltage and a current output from the storage battery B to remove a DC bias component and a noise component; An output device 2 for outputting an application signal selected by the processing device 1; A bandwidth controller 3 which compensates the signal detected by the detection device 4 to the signal output from the output device 2 and limits or cuts off the bandwidth; A power amplifier 6 for amplifying the signal compensated by the controller 3 to continuously apply a constant voltage or a constant current to the storage battery B; A converter 5 for compensating the compensation signal provided from the processing device 1 to the signal detected by the detection device 4 and outputting a measurement result signal; Portable battery pack non-destructive evaluation device using AC impedance measurement technology, characterized by consisting of an asynchronous FIFO / gain and offset error corrector (8) (8 ') that facilitates high-speed data transfer and corrects gain and offset errors. The method of claim 1, Portable battery using the AC impedance measurement technology, characterized in that it comprises a remote control device 7 for remotely controlling the applied signal selected from the processing device 1, the compensation signal and the measurement result signal to be supplied Pack nondestructive evaluation device. The method according to claim 1 or 2, The output device 2, An alternator 21 for generating an alternating current component of the application signal selected by the processing apparatus 1; An attenuator 22 that attenuates the signal generated by the alternator 21; A bias supply 26 for outputting a DC component of the application signal selected by the processing apparatus 1, A slope limiter 27 for removing an initial oscillation component of a DC component applied from the bias supply 26 and Portable battery pack non-destructive evaluation device using the AC impedance measurement technology, characterized in that composed of a mixer (25) for combining the output signal of the attenuator (22) and the output signal of the slope limiter (27). The method according to claim 1 or 2, The converter 5, A gain and offset error corrector (56) (56 ') for outputting a compensation signal for measurement error and leakage, A DC bias voltage compensation DAC 51 for converting the voltage compensation signal provided from the gain and offset error corrector 56 and the processing apparatus 1 into analog; A DC bias current compensation DAC 51 'for converting the current compensation signal provided by the gain and offset error corrector 56' and the processing apparatus 1 into analog; Adders 52 and 52 'for combining the compensation signal converted by the DC bias voltage compensation DAC 51 and the DC bias current compensation DAC 51' and the voltage signal detected by the detection device 4; Amplifiers 53 and 53 'for amplifying the signals output from the adders 52 and 52', Low pass filters 54 and 54 'for filtering signals of the amplifiers 53 and 53', A voltage ADC 54 for converting the signal filtered by the low pass filter 54 into a digital signal; Portable battery pack non-destructive evaluation device using an alternating current impedance measurement technology, characterized in that the current ADC (54 ') for converting the signal filtered by the low-pass filter (54') to digital. In the system for measuring the drive characteristics of the storage battery (B), A processing device 1 for selecting an applied signal required for measurement, providing a voltage and current compensation signal according to an internal error of the system, and analyzing the measurement result signal accordingly to calculate data on driving characteristics of the storage battery B; , Asynchronous FIFO / Gain and Offset Error Compensator (8) (8 ') that facilitates high-speed data transfer and compensates for gain and offset errors. The asynchronous FIFO / gain and offset error corrector is equipped with a single module (M) composed of an output device (2), a bandwidth controller (3), a detection device (4), a converter (5) and a power amplifier (6). To the switching device 91 which transmits the data received at (8) to the single module M, respectively, and transmits the output signal of each single module M to the asynchronous FIFO / gain and offset error corrector 8 '. Multi-channel measurement system using a portable battery pack non-destructive evaluation device using the AC impedance measurement technology, characterized in that the multi-measuring device (9) made. The method of claim 5, Portable battery using the AC impedance measurement technology, characterized in that it comprises a remote control device 7 for remotely controlling the applied signal selected from the processing device 1, the compensation signal and the measurement result signal to be supplied Multichannel Measurement System Using Pack Nondestructive Evaluation System.