JP2010281587A - Electrochemical reaction measuring method and electrochemical reaction measuring instrument - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrochemical reaction measuring method enabling measurement considering an effect of a polarization state, and an electrochemical reaction measuring instrument. <P>SOLUTION: A response signal is acquired by being associated with a phase of a perturbation signal. Impedance is calculated using the response signal where the phase of the perturbation signal is within a predetermined range in the acquired response signal. For example, the impedance is calculated using the response signal during a period when the perturbation signal shows a positive or negative value. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electrochemical reaction measurement method and an electrochemical reaction measurement device that give a perturbation signal to an object to be measured and perform measurement related to an electrochemical reaction of the object to be measured based on a response signal generated by the perturbation signal.

  As a method for measuring the impedance of a fuel cell or other cell, a method is known in which a perturbation signal is given to the cell and the impedance is calculated based on the response signal at that time. In this method, power is generated at a certain operating point (output current Idc, output voltage Vdc), and an alternating current perturbation Iac of frequency f is superimposed to obtain the voltage response signal Vac, and impedance at frequency f is calculated. . Alternatively, the AC voltage perturbation Vac of the frequency f is superimposed at the operating point, the current response signal Iac is acquired, and the impedance at the frequency f is calculated.

JP 2007-250365 A

  On the other hand, the following chemical reaction formula (formula (1)) shows the balance of the reaction (polarization state) at the operating point (output current Idc, output voltage Vdc) at the time of impedance measurement.

  Here, the oxidation-reduction reaction of substance A is shown as a simple example, but in the state of polarization, the rightward reaction is more popular than the leftward reaction in this chemical reaction formula, and a rightward reaction occurs from the outside. It is the state that is observed.

  As described above, in the impedance measurement of the battery, the impedance measurement is performed in a state where a perturbation signal is further given to a system that is stable (reached to an equilibrium state) at a certain operating point (polarization state). For this reason, the response to the perturbation in the polarization direction may be different from the response to the perturbation in the direction opposite to the polarization. However, in the conventional impedance measurement, the impedance is calculated by combining both responses, and the battery response cannot be analyzed in detail in consideration of the influence of the polarization state.

  An object of the present invention is to provide an electrochemical reaction measurement method and an electrochemical reaction measurement apparatus that enable measurement in consideration of the influence of the polarization state.

The electrochemical reaction measuring method of the present invention is the electrochemical reaction measuring method in which a perturbation signal is given to an object to be measured, and the electrochemical reaction measurement method for measuring an electrochemical reaction of the object to be measured based on a response signal generated by the perturbation signal. Obtaining a signal in association with the phase of the perturbation signal, and calculating an impedance using a response signal having the phase within a predetermined range among the response signals obtained by the obtaining step. It is characterized by providing.
According to this electrochemical reaction measurement method, the impedance is calculated using a response signal whose phase is in a predetermined range among the acquired response signals, so that measurement in consideration of the influence of the polarization state is possible.

  In the calculating step, the impedance may be calculated using a response signal in a period in which the perturbation signal shows a positive or negative value.

In the calculating step, the impedance may be calculated using a response signal in a period in which the time derivative of the perturbation signal shows a positive or negative value.
The electrochemical reaction measurement device of the present invention is the electrochemical reaction measurement device that gives a perturbation signal to the object to be measured and performs measurement related to the electrochemical reaction of the object to be measured based on a response signal generated by the perturbation signal. Response signal acquisition means for acquiring a signal in association with the phase of the perturbation signal, and among the response signals acquired by the response signal acquisition means, the impedance is calculated using a response signal whose phase is in a predetermined range And an impedance calculating means.
According to this electrochemical reaction measuring device, since impedance is calculated using a response signal having a phase in a predetermined range among the acquired response signals, measurement considering the influence of the polarization state is possible.

  The impedance calculation means may calculate the impedance using a response signal during a period in which the perturbation signal shows a positive or negative value.

  The impedance calculation means may calculate the impedance using a response signal in a period in which the time derivative of the perturbation signal shows a positive or negative value.

  According to the electrochemical reaction measurement method of the present invention, the impedance is calculated using a response signal having a phase in a predetermined range among the acquired response signals, so that measurement in consideration of the influence of the polarization state is possible. .

  According to the electrochemical reaction measuring device of the present invention, the impedance is calculated using a response signal whose phase is in a predetermined range among the acquired response signals, so that measurement in consideration of the influence of the polarization state is possible. .

The block diagram which shows the structure of the measuring device for performing the electrochemical reaction measuring method by this invention. The flowchart which shows the procedure in the electrochemical reaction measuring method by this invention. The figure which shows the example which superimposed the current perturbation signal of the frequency f and the amplitude Iac on the electric current (Idc) in the operating point (Idc, Vdc). It is a figure which shows the division | segmentation method by the phase of a perturbation signal, (a) is a figure which illustrates the waveform of a perturbation signal and a response signal, (b) is an example which divides | segments the period into two periods according to the polarity of a perturbation signal. (C) is a figure which shows the example which isolate | separated the phase into four according to before and after the peak of a perturbation signal in addition to the polarity of a perturbation signal.

  Hereinafter, embodiments of the electrochemical reaction measurement method according to the present invention will be described.

  FIG. 1 is a block diagram showing a configuration of a measuring apparatus for performing an electrochemical reaction measuring method according to the present invention.

  As shown in FIG. 1, an electronic load 2 is connected to a fuel cell 1 as an object to be measured, and a predetermined operating point is given to the battery 1 via the electronic load 2, and an operating voltage or operation at the operating point is given. A perturbation signal (voltage perturbation signal or current perturbation signal) is superimposed on the current.

  As illustrated in FIG. 1, the measurement device 3 includes a response signal acquisition unit 31 that acquires a response signal in association with a phase of a perturbation signal, and a phase of a response signal acquired by the response signal acquisition unit 31 has a predetermined phase. Impedance calculation means 32 for calculating impedance using a response signal in the range. In addition, the measuring device 3 is provided with a load control unit 33 that controls the electronic load 2 and a display unit 34 that displays an impedance calculation result and the like in the impedance calculation means 32.

  Steps S1 to S9 in FIG. 2 are flowcharts showing the procedure of impedance measurement.

  In step S1 of FIG. 2, measurement conditions are set based on a user instruction. Here, the operating point (Idc or Vdc) for measurement, the frequency of the perturbation signal, and the amplitude of the perturbation signal are set.

  Next, in step S2, the electronic load 2 is controlled by the load control unit 33, so that power generation of the fuel cell 1 is started at the operating point set in step S1.

  Next, in step S3, the process waits for the power generation state of the fuel cell 1 to stabilize, and then proceeds to step S4.

  In step S4, the load control unit 33 controls the electronic load 2 so that the perturbation signal (voltage perturbation signal or current perturbation signal) corresponding to the measurement condition set in step S1 is changed to the voltage (Vdc) at the operating point. Superimpose on the current (Idc).

  FIG. 3 shows an example in which the current perturbation signal having the frequency f and the amplitude Iac is superimposed on the current (Idc) at the operating point (Idc, Vdc). In this case, a voltage response signal (Vac) for the current perturbation signal is acquired.

  Next, in step S5, the response signal acquisition unit 31 acquires the value of the current response signal at a predetermined timing, and acquires the polarity of the current perturbation signal from the load control unit 33.

  Next, in step S6, it is determined whether or not the polarity of the perturbation signal acquired in step S5 is positive. If the determination is affirmative, the process proceeds to step S7, and if the determination is negative, the process proceeds to step S8.

  In step S7, a positive mark is attached to the value of the response signal acquired in step S5, the value is stored, and the process proceeds to step S9. On the other hand, in step S8, a negative mark is attached to the value of the response signal acquired in step S5, the value is stored, and the process proceeds to step S9.

  In step S9, it is determined whether or not acquisition of all response signal values has been completed. If the determination is affirmative, the process ends. If the determination is negative, the process returns to step S5.

  As described above, in the procedure shown in FIG. 2, the acquired response signal is stored with a mark corresponding to the polarity of the current perturbation signal.

  In addition, what is necessary is just to increase the frequency | count of repetition of step S5-step S9, when improving the measurement precision of a response signal value. Moreover, what is necessary is just to perform the process of step S4-step S9 about each frequency, when switching the frequency of a perturbation signal.

  Steps S <b> 11 to S <b> 12 in FIG. 2 are flowcharts illustrating a processing procedure in the impedance calculation unit 32. This process is executed using the response signal values stored by the response signal value acquisition process (steps S1 to S9).

  In step S11 of FIG. 2, the response signal value stored with the response signal value acquisition process (steps S1 to S9) is extracted with a positive mark, and the impedance is calculated based on the extracted response signal value. calculate.

  Next, in step S12, the response signal value stored by the response signal value acquisition process (steps S1 to S9) is extracted with a negative mark, and the impedance is calculated based on the extracted response signal value. Calculate and finish the process.

  FIG. 4A is a diagram illustrating waveforms of the perturbation signal and the response signal.

  As shown in FIG. 4A, even when a sine wave is given as a perturbation signal, the response signal takes a waveform with distortion due to a loss of symmetry between positive and negative due to the influence of the polarization state in the fuel cell 1.

  As shown in FIG. 4B, in the above embodiment, the period is divided into two periods according to the polarity of the perturbation signal, and the impedance in each period is calculated. Positive and negative values can be calculated as corresponding values.

  FIG. 4C shows an example in which the phases (I to IV) are separated before and after the peak of the perturbation signal in addition to the polarity of the perturbation signal. In this case, the period of the perturbation signal is separated into four phases by the combination of the positive and negative values of the perturbation signal and the positive and negative values of the time derivative of the perturbation signal, and the impedance in each phase is calculated independently. It becomes possible.

  As described above, according to the electrochemical reaction measurement method of the present invention, the impedance is calculated using a response signal whose phase is in a predetermined range among the acquired response signals, so that the influence of the polarization state is considered. Measurement is possible. Thereby, it becomes possible to analyze the electrochemical behavior or the like in the object to be measured in more detail.

  The scope of application of the present invention is not limited to the above embodiment. The present invention is widely applied to an electrochemical reaction measuring method and an electrochemical reaction measuring device for applying a perturbation signal to an object to be measured and performing measurement related to an electrochemical reaction of the object to be measured based on a response signal generated by the perturbation signal. Can be applied.

31 Response signal acquisition means 32 Impedance calculation means

Claims (6)

In an electrochemical reaction measurement method for giving a perturbation signal to an object to be measured, and performing measurement related to an electrochemical reaction of the object to be measured based on a response signal generated by the perturbation signal,
Obtaining the response signal in association with the phase of the perturbation signal;
Of the response signals acquired by the acquiring step, calculating the impedance using a response signal whose phase is in a predetermined range;
An electrochemical reaction measuring method comprising: 2. The electrochemical reaction measuring method according to claim 1, wherein, in the calculating step, impedance is calculated using a response signal in a period in which the perturbation signal shows a positive or negative value. The electrochemical reaction measurement method according to claim 1 or 2, wherein, in the calculating step, the impedance is calculated using a response signal in a period in which a time derivative of the perturbation signal shows a positive or negative value. In an electrochemical reaction measuring device that gives a perturbation signal to an object to be measured and performs measurement related to an electrochemical reaction of the object to be measured based on a response signal generated by the perturbation signal.
Response signal acquisition means for acquiring the response signal in association with the phase of the perturbation signal;
Among the response signals acquired by the response signal acquisition means, impedance calculation means for calculating impedance using a response signal whose phase is in a predetermined range;
An electrochemical reaction measuring device comprising: 5. The electrochemical reaction measuring device according to claim 4, wherein the impedance calculating means calculates the impedance using a response signal during a period in which the perturbation signal shows a positive or negative value. 6. The electrochemical reaction measuring device according to claim 4 or 5, wherein the impedance calculating means calculates the impedance using a response signal in a period in which a time derivative of the perturbation signal shows a positive or negative value.

Images