JP2003057121A - Method for measuring thermoelectromotive force of thermoelectric material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the influence of a voltage resulting from a thermocouple in measuring the thermoelectromotive force of a thermoelectric material using the thermocouple. SOLUTION: A heater 11 on the low-temperature side of a thermoelectric material 10 and a heater 12 on the high-temperature side hereof are used to measure a thermoelectromotive force while eliminating a difference of temperature between the heaters 11 and 12, thereby measuring a voltage resulting from the thermocouple derived from the heaters 11 and 12. The voltage derived from the thermocouple is subtracted from an actually measured apparent electromotive force to accurately measure a thermoelectromotive force derived from the thermoelectric material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for measuring thermoelectromotive force of a thermoelectric material using a thermocouple, and in particular, by eliminating the influence of the electromotive force derived from the thermocouple, The present invention relates to a technique for accurately measuring electric power.

[0002]

2. Description of the Related Art Conventionally, a thermoelectric material has been evaluated for its performance by obtaining a Seebeck coefficient from the measured thermoelectromotive force and by using the Seebeck coefficient. Such thermoelectromotive force is
A thermocouple is contacted with each of the low temperature side and high temperature side of the thermoelectric material with a temperature difference, and along with the temperature measurement of the thermocouple, the electromotive force measured by interposing a voltmeter between both thermocouples is used. It is considered as an electromotive force.

[0003]

The thermoelectromotive force of the thermoelectric material is measured by using two thermocouples in the above-mentioned manner. In such measurement, the thermoelectromotive force between the same materials of both thermocouples is measured. It is premised that it does not generate electromotive force. Therefore, the electromotive force between both thermocouples contacting the low temperature side contact portion and the high temperature side contact portion of the thermoelectric material has been used as it is as the thermoelectromotive force.

The present inventor has encountered a case in which the Seebeck coefficient evaluation stage of a thermoelectric material gives a result which is far from the expected value expected from the initially measured thermoelectromotive force. In order to pursue the cause, a calibration experiment was performed using a standard sample (chromel constantan). as a result,
It was found that the measured electromotive force was abnormal.

The thermoelectromotive force of the thermoelectric material was measured very stably, and seemingly reasonable data were obtained. At that stage, no abnormality was noticed. As shown in FIG. 8, the thermoelectromotive force is measured by applying a temperature difference to the inside of the thermoelectric material 1 as a sample by the heater 2 installed in the lower electrode portion of the thermoelectric material 1 and contacting the thermocouple 3. The electromotive force between the low temperature side contact part of the thermoelectric material 1 and the high temperature side contact part of the thermoelectric material 1 with which the thermocouple 4 is contacted is measured by the voltmeter 5 interposed between both thermocouples 3 and 4. did. The electromotive force measured by diverting the thermocouples 3 and 4 for temperature measurement in this manner was used as the thermoelectromotive force of the thermoelectric material 1.

In such measurement, it is premised that the characteristics of the same kind of material of the alumel chromel thermocouple used as the lead wires 3a, 4a for measuring the electromotive force are equivalent. However, it was found that the above-mentioned trouble occurred this time because there was a difference in the characteristics of the lead wires 3a and 4a of the alumel chromel thermocouple which were considered to be equivalent.

That is, since there is a difference in characteristics between the pair of lead wires 3a and 4a, a voltage that causes noise is generated between the lead wires 3a and 4a and is added to the original thermoelectromotive force of the thermoelectric material 1 as a bias. It was considered that this was a phenomenon that occurred.

The measurement of the thermoelectromotive force of the conventional thermoelectric material has been performed without considering the influence of the electromotive force derived from the thermocouple itself.

Since the thermoelectromotive force in the thermoelectric material is an extremely small voltage on the order of μV, the influence of the voltage generated from the above-mentioned deviation of the equivalence of the lead wires in the thermocouple is extremely large. This will have a significant impact on the evaluation of thermoelectric materials. The noise voltage derived from such a thermocouple greatly exceeds the error range in thermoelectromotive force measurement of thermoelectric materials. Furthermore, the seriousness of such a problem is that the anomaly cannot be clearly confirmed at the stage of measuring the electromotive force.

An object of the present invention is to obtain an accurate thermoelectromotive force in the measurement of thermoelectromotive force of a thermoelectric material by eliminating the influence of a voltage which becomes noise due to the thermocouple itself used for the measurement. Is to

[0011]

Among the inventions disclosed in the present application, a brief description will be given to the outline of typical ones.
It is as follows.

That is, the present invention is a measuring system in which thermocouples are respectively brought into contact with the high temperature side and the low temperature side of thermoelectric materials having different temperatures, and the electromotive force between the high temperature side contact portion and the low temperature side contact portion is set. Is a thermoelectromotive force measuring method of a thermoelectric material for determining the thermoelectromotive force of the thermoelectric material by measuring the thermoelectric power by removing from the electromotive force a noise voltage derived from the thermocouple that becomes noise generated by the thermocouple itself. It is characterized in that the thermoelectromotive force of the material is obtained.

The noise voltage derived from the thermocouple is measured by the measuring system together with the measurement of the electromotive force between the high temperature side contact portion and the low temperature side contact portion. The noise voltage derived from the thermocouple is a measurement of electromotive force between the high temperature side contact portion and the low temperature side contact portion of the thermoelectric material with a temperature difference, and the high temperature side contact portion of the thermoelectric material and the It is characterized in that it is obtained by generating a state where there is no temperature difference with the low temperature side contact portion at least once and measuring the electromotive force in that state.

Alternatively, the measurement of the electromotive force between the high temperature side contact portion and the low temperature side contact portion of the thermoelectric material is exchanged with a state in which the high temperature side contact portion and the low temperature side contact portion are exchanged with each other. Between the high temperature side contact part and the low temperature side contact part of the thermoelectric material by determining the arithmetic mean value of the electromotive force in the exchanged state and the electromotive force in the non-exchanged state. The noise voltage derived from the thermocouple may be excluded from the electromotive force of 1.

The thermoelectromotive force measuring method for such a thermoelectric material may be carried out using an electromotive force measuring system having the following configuration. For example, by installing a thermoelectric material in between, a plurality of heat sources that generate a temperature difference in the thermoelectric material, a high temperature side thermocouple that contacts the high temperature side of the thermoelectric material and measures the temperature of the high temperature side contact portion, A low temperature side thermocouple that contacts the low temperature side of the thermoelectric material to measure the temperature of the low temperature side contact portion, a temperature control unit that controls the temperature of the plurality of heat sources with a temperature control program by a computer, and the high temperature side thermocouple With the low temperature side thermocouple, electromotive force measuring means for measuring the electromotive force between the high temperature side contact portion and the low temperature side contact portion to the thermoelectric material,
Based on a plurality of measured electromotive force measured by the electromotive force measuring means under different measurement conditions, by the correction program by the computer, the thermocouple-derived noise voltage generated by the thermocouple itself is removed from the electromotive force, etc. An electromotive force measurement system having a thermocouple-derived noise voltage correction means for correction can be used.

In such an electromotive force measuring system, for example, a noise voltage derived from a thermocouple based on the thermocouple is excluded based on a plurality of measured electromotive forces measured by the electromotive force measuring means under different measurement conditions. Is a state in which the temperature of the high temperature side heat source and the low temperature side heat source of the plurality of heat sources is reversed by the temperature control means to change the measurement condition, and the temperature of the high temperature side and the low temperature side of the thermoelectric material is reversed. Then, the electromotive force before the reversal and the electromotive force after the reversal can be arithmetically averaged.

Alternatively, based on the plurality of measured electromotive forces measured by the electromotive force measuring means under different measurement conditions, the temperatures of the high temperature side heat source and the low temperature side heat source among the plurality of heat sources are controlled by the temperature control means. By setting the same temperature to eliminate the temperature difference provided in the thermoelectric material, from the electromotive force measured with the temperature difference provided in the thermoelectric material, subtract the value measured in the state where the temperature difference is eliminated It can also be done by.

As a method of accurately measuring the thermoelectromotive force of the thermoelectric material, in addition to the above configuration, for example, a temperature measuring system and an electromotive force measuring system are provided as separate systems from the beginning, and in the electromotive force measuring system, The influence of noise voltage derived from a thermocouple may be eliminated by using a material that is more thermochemically stable than before.

That is, by providing a dedicated lead wire for electromotive force measurement separately from that for temperature measurement, the thermocouples to be brought into contact with each other at the low temperature side contact portion and the high temperature side contact portion are provided separately from the thermocouple. The influence of noise voltage may be eliminated from the electromotive force generated between the high temperature side contact portion and the low temperature side contact portion of the thermoelectric material. The lead wire for thermoelectromotive force measurement is, for example, Ag, Pt, Au,
It may be formed by using a thermally and chemically stable material such as Cu.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings.

(Embodiment 1) In the present embodiment, a thermocouple-derived voltage derived from a thermocouple used for measuring a thermoelectromotive force of a thermoelectric material is measured by an electromotive force measuring system of the thermoelectric material, and A method for accurately measuring the thermoelectromotive force derived from the thermoelectric material by calibrating by removing the voltage derived from the thermocouple as noise will be described.

In a system for measuring the thermoelectromotive force of a thermoelectric material using a thermocouple, to be precise, the thermoelectric material-derived thermoelectromotive force V1 which is the original thermoelectromotive force derived from the thermoelectric material and the thermoelectric material are measured. The electromotive force V as the sum of the addition of the thermocouple-derived noise voltage V2 derived from the thermocouple itself used in the above is measured.

In measuring the electromotive force of a conventional thermoelectric material,
Thermocouple-derived noise voltage V2 generated by the thermocouple itself
The measurement is performed on the assumption that ≈0, and the electromotive force obtained by adding V1 and V2 (hereinafter, this added electromotive force may be referred to as apparent electromotive force V) is directly the thermoelectromotive force V1 derived from the thermoelectric material. It was considered to be.

However, the present inventor has confirmed that the assumption that V2≈0 may not be satisfied in some cases, and by subtracting the noise voltage V2 derived from the thermocouple from the apparent electromotive force V, the thermoelectric material-derived thermal induction is generated. Electric power (= thermoelectromotive force) V1
It was found that V-V2 was accurately obtained.

Regarding the measurement of the noise voltage V2 derived from the thermocouple, considering that the thermoelectromotive force of the thermoelectric material itself is an extremely small voltage, the noise voltage V2 derived from the thermocouple is taken into consideration.
The measurement conditions of 2 and the apparent electromotive force V are required to be the same as much as possible, and it is required to eliminate the minute noise due to the difference of the measurement conditions as much as possible.

Therefore, considering both measurements under the same conditions as much as possible, the thermoelectromotive force measurement system of the thermoelectric material and the measurement system of the noise voltage V2 derived from the thermocouple should not be physically independent. The present inventor considered that it is not preferable, and that it is preferable to be able to measure the noise voltage derived from the thermocouple in the thermoelectromotive force measurement system of the thermoelectric material. The present inventor has devised a method capable of measuring an apparent electromotive force V and a thermocouple-derived noise voltage V2 in the same measurement system, and arrived at the present invention.

The thermoelectromotive force measuring method for such a thermoelectric material is carried out by constructing a measuring system as shown in FIG. The thermoelectric material 10 to be measured can be heated by bringing its upper end side and lower end side into contact with the heaters 11 and 12 independently. In the state shown in FIG. 1A, the upper end side where the heater 11 is provided is set to the low temperature TL and the lower end side is set to the high temperature TH.

In addition, the thermoelectric material 10 is provided with a pair of thermocouples 21 and 22, the thermocouple 21 is brought into contact with the low temperature side of the thermoelectric material 10, and the thermocouple 22 is brought into contact with the high temperature side thereof. A voltmeter 30 is interposed between both thermocouples 21 and 22. The temperature of the low temperature side of the thermoelectric material 10 is measured by the thermocouple 21, and the temperature of the high temperature side is measured by the thermocouple 22, and the voltmeter 30 interposed between the thermocouples 21 and 22 also makes contact with the low temperature side contact portion. The apparent electromotive force V of the thermoelectric material 10 in the state where a temperature difference is provided between the high temperature side contact portion is measured.

The electromotive force measured in the state shown in FIG. 1A is an apparent electromotive force V (= V1 + V) obtained by adding the thermoelectromotive force V1 derived from the thermoelectric material and the noise voltage V2 derived from the thermocouple.
2).

On the other hand, in the measurement system shown in FIG. 1 (A), as shown in FIG. 1 (B), the temperature of the heaters 11 and 12 is controlled so that the heaters 11 and 12 are kept at the same temperature.
That is, when the isothermal TE is set, a state in which there is no temperature difference occurs in the thermoelectric material 10. When the electromotive force is measured by the voltmeter 30 in this state, the thermoelectric material-derived thermoelectromotive force V1 based on the temperature difference of the thermoelectric material 10 becomes V1 = 0, and the measured apparent electromotive force V is the thermocouple-derived noise voltage V2. It should be.

Therefore, in the same measurement system, as shown in FIG.
By forming the state shown in FIG. 1 and the state shown in FIG. 1B, the apparent electromotive force V and the noise voltage V2 derived from the thermocouple are collectively measured under the same measurement conditions in the same measurement system. The thermoelectromotive force V1 derived from the thermoelectric material can be accurately determined as V-V2 based on both measured values.

For example, such a measurement system includes heaters 11 and 1
The temperature control of 2 and the temperature at each temperature in the thermocouple and the apparent electromotive force V may be measured by a control program preset by a computer. The apparent electromotive force V is measured and stored by the computer when there is a temperature difference between the heaters 11 and 12, and it is also apparent that the temperature difference between the heaters 11 and 12 is not controlled by controlling the temperature of the heaters 11 and 12. Of the electromotive force V (= noise voltage V2 derived from the thermocouple) is stored, and when the electromotive force V2 derived from the thermocouple is subtracted from the apparent electromotive force V at the time of output, it is derived from the thermoelectric material 10. The thermoelectromotive force can be measured with high accuracy.

When measuring the noise voltage V2 derived from the thermocouple, a temperature difference is not provided between the heaters 11 and 12, but the heaters 11 and 12 are not provided with such a temperature difference.
Is the high temperature T of the heater 12 on the high temperature side.
It may be set so as to match H, or the temperature of the high temperature side heater 12 may be set to the low temperature TL of the low temperature side heater 11.
May be adjusted to. Furthermore, the heater 11,
The isothermal set temperature of 12 is the high temperature TH,
Alternatively, a temperature other than the low temperature TL, for example, a temperature between TH and TL, a temperature higher than TH, or a temperature lower than TL may be set.

The effectiveness of the thermoelectromotive force measuring method of the thermoelectric material described in the present embodiment was verified by the following experiments.

In the experiment, the thermoelectric material 1 having the structure shown in FIG.
As 0, a standard sample chromel constantan whose thermoelectromotive force value was already known was used. Heaters 11 and 12
By applying a temperature difference of 4 ° C. to the standard sample, the apparent electromotive force V at each temperature measured in that state is shown in FIG.
Value 110. In FIG. 2, the vertical axis represents the electromotive force (μv) and the horizontal axis represents the sample temperature (° C.).

In addition, the apparent electromotive force (= noise voltage V2 derived from thermocouple) when the temperature difference between the heaters 11 and 12 was set to 0 was indicated by a value 120. The thermoelectric material-derived thermoelectromotive force V1 (marked by black squares) obtained by calibrating the noise voltage V2 derived from the thermocouple is shown as a value V-V2 from V and V2 measured in this way as a value 130.

A value 1 indicating the thermoelectromotive force V1 of the thermoelectric material.
No. 30 showed a good agreement with the thermoelectromotive force of the standard sample described in the literature (the value shown by the dotted dotted line). However, the value 110 indicating the apparent electromotive force V without considering the noise voltage V2 derived from the thermocouple is 800 ° C. higher than the value 130.
Then, the electromotive force was measured as high as about 70 μv, and it was confirmed that a large measurement error occurred due to the noise voltage V2.

From this, it was confirmed that the method for measuring the thermoelectromotive force of the thermoelectric material proposed in the first embodiment can be effectively used for accurate measurement of the electromotive force of the thermoelectric material.

(Embodiment 2) In the thermoelectromotive force measuring method of the thermoelectric material of the present embodiment, the voltage derived from the thermocouple is positive, that is, positive, by exchanging the high temperature side condition and the low temperature side condition of the thermoelectric material. , And minus are reversed, the apparent electromotive force V of both the exchanged state and the state before the exchange is measured, and the arithmetic mean of the apparent electromotive force V measured in each state is obtained. The noise voltage V2 derived from the thermocouple contained in the apparent electromotive force V measured in each state can be canceled out by calculation by arithmetically averaging the apparent electromotive forces in the different states. This is a method for obtaining the thermoelectromotive force derived from the material with high accuracy.

Also in this embodiment, the measurement is performed using the measurement system having the structure shown in FIG. That is, in such a measurement system, the temperature controllable heater 11 and the temperature controllable heater 12 are provided on the upper end side of the thermoelectric material 10 and the temperature controllable heater 12 on the lower end side of the thermoelectric material 10. It is configured so that it can be set to the high temperature side. The heaters 11 and 12 are arranged so that they can be interchanged.

The electromotive force of the thermoelectric material measured by the measuring system shown in FIG. 3A is V as described in the first embodiment.
(Apparent electromotive force) = V1 (thermoelectromotive force derived from thermoelectric material) +
It becomes V2 (noise voltage derived from thermocouple).

Therefore, if the contact positions of the heaters 11 and 12 on the thermoelectric material 10 are exchanged without changing the setting conditions of the thermocouples 11 and 12 for the thermoelectric material 10 shown in FIG. As shown in B),
The upper and lower heaters 11 and 12 are exchanged by rotating them as shown by arrows in FIG. In this way, the low temperature side of the thermoelectric material 10 is set to the high temperature TH and the high temperature side is set to the low temperature TL. In this way, the thermoelectric material 10 and the thermocouples 21, 2
Thermoelectric material 1 without changing the measurement environment with 2
The apparent electromotive force V measured in the state where the high temperature side and the low temperature side of 0 are exchanged should be V = V1-V2 when the thermoelectric material-derived thermoelectromotive force V1 and the thermocouple-derived electromotive force V2 are set. is there.

Then, by calculating the arithmetic mean of the apparent electromotive force V measured in the state of FIG. 3A and the electromotive force V measured in the state of FIG. 3B. , The noise voltage V2 derived from the thermocouple is canceled out, and an accurate thermoelectromotive force V1 derived from the thermoelectric material can be obtained. That is,
From the expression {(V1 + V2) + (V1-V2)} / 2,
The arithmetic mean should be calculated. In (V1 + V2) of this equation, the apparent electromotive force measured in FIG.
The apparent electromotive force measured in FIG. 3B may be substituted in 2) to perform the calculation.

For example, such a measuring system includes a heater 11,
12 temperature control, temperature at each temperature in thermocouple,
The electromotive force V may be measured by a control program preset by a computer. That is,
By the computer, the heaters 11 and 12 shown in FIG.
The apparent electromotive force V measured in the state is stored, and then the apparent electromotive force is stored in a state where the heaters 11 and 12 are exchanged as shown in FIG. 3B, and the apparent electromotive force is stored in the computer. The electromotive force may be output in a state where the noise voltage V2 derived from the thermocouple is canceled by performing calculation by an arithmetic mean calculation formula programmed in advance as the noise voltage correction unit derived from the thermocouple.

In the above description, the case where the arithmetic mean of one measurement is obtained is explained, but naturally,
The arithmetic mean of a plurality of measurements may be obtained.

The effectiveness of the thermoelectromotive force measuring method for the thermoelectric material described above was verified by the following experiments.

In the experiment, the thermoelectric material 1 having the structure shown in FIG.
As 0, a standard sample chromel constantan whose thermoelectromotive force value was already known was used. Heaters 11 and 12
By applying a temperature difference of 4 ° C. to the standard sample, the apparent electromotive force V at each temperature measured in that state is shown in FIG.
The values 210 and 220 are shown. The values 210 and 220 are
The measured values correspond to the respective configurations shown in FIGS. 3 (A) and 3 (B).

In addition, the thermoelectric material-derived electromotive force V1 obtained by taking the arithmetic mean of the apparent electromotive forces V shown by the values 210 and 220, respectively, is shown by the value 230 (marked by ■).

A value of 2 indicating the thermoelectromotive force V1 of the thermoelectric material.
No. 30 showed a good agreement with the thermoelectromotive force (value indicated by the broken line) of the standard sample described in the literature. However, the values 210 and 220 indicating the apparent electromotive force V not considering the noise voltage V2 derived from the thermocouple are 80
It was confirmed that a large measurement error occurred due to the noise voltage V2 of about ± 70 μv at 0 ° C.

From this, it was confirmed that the method for measuring the thermoelectromotive force of the thermoelectric material proposed in the second embodiment can be effectively used for accurate electromotive force measurement of the thermoelectric material.

In the measuring method described in the second embodiment, the measurement can be performed with the configuration in which the contact positions of the heaters 11 and 12 are exchanged as described above, but the temperature control of the configuration described in the first embodiment can be performed. It is also possible to use a measurement system provided with the configured heaters 11 and 12.

That is, in the state shown in FIG. 1 (A), the apparent electromotive force V is measured as described above. After that, heater 1
By controlling the temperatures 1 and 12, as shown in FIG.
The heater 11 on the low temperature side is set to the high temperature TH, and the heater 12 on the high temperature side is set to the low temperature TL. The apparent electromotive force V is measured in a state where the temperature settings of the respective heaters 11 and 12 have been changed and the low temperature side and the high temperature side of the thermoelectric material 10 have been interchanged. By obtaining the arithmetic mean of the two types of apparent electromotive force V in the state of FIG. 1 (A) and the state of FIG. 5 (A) thus measured, the thermoelectromotive force derived from the thermoelectric material is calculated as described above. V1 may be obtained with high accuracy.

Furthermore, without changing the heaters 11 and 12 or changing the temperature of the heaters 11 and 12, the setting condition of the thermoelectric material 10 and the heaters 11 and 12 is shown in FIG.
Even when the contact positions of the thermocouples 21 and 22 with respect to the thermoelectric material 10 are switched while maintaining the state shown in (A), the electromotive force can be measured using the arithmetic mean described in the second embodiment.

That is, the thermocouple 21 that was in contact with the high temperature side of the thermoelectric material 10 and the thermocouple 22 that was in contact with the low temperature side of the thermoelectric material 10 were replaced with each other, and as shown in FIG. Alternatively, the pair 21 may be replaced with the high temperature side and the thermocouple 22 may be replaced with the low temperature side for the measurement.

The apparent electromotive force V in the configuration shown in FIG.
Of the thermocouple 2 as shown in FIG. 5 (B).
Replace the contact position of the thermoelectric material 10 of 1 and 22,
The apparent electromotive force V in the replaced state is measured.
If the arithmetic mean of the apparent electromotive forces is calculated, the noise voltage 2 from the thermocouple included in the apparent electromotive forces is 2
Are canceled out, and the thermoelectromotive force V1 derived from the thermoelectric material can be obtained with high accuracy.

Further, in obtaining the accurate thermoelectromotive force V1 derived from the thermoelectric material by using the arithmetic mean in each of the states shown in FIGS. 1 (A) and 5 (A),
The heater 11 may be heated from the TL side to the TH side, and the heater 12 may be cooled in parallel from the high temperature TH to the low temperature TL in parallel.
Nos. 1 and 12 should generate a state where the temperatures are the same between the low temperature TL and the high temperature TH. Therefore, by measuring the apparent electromotive force at this isothermal point, the thermocouple-derived electromotive force V2 can be measured as described in the first embodiment.

(Embodiment 3) In the method for measuring thermoelectromotive force of a thermoelectric material of the present embodiment, a system for measuring electromotive force is added to the thermocouple in addition to the temperature measuring system for the thermocouple.
This is a method for obtaining an accurate thermoelectromotive force derived from a thermoelectric material in a state where the influence of noise voltage derived from a thermocouple is excluded.

This method may be carried out by using the measuring system having the structure shown in FIG. In the measurement system, the thermoelectric material 10 is in contact with the low temperature heat source 13 at the upper end side and the high temperature heat source 14 at the lower end side. In this way, a pair of thermocouples 23 and 24 are provided on the high temperature side and the low temperature side of the thermoelectric material 10 having a temperature difference inside, and the temperature on the low temperature side is controlled by the thermocouple 23. It can be measured by the thermocouple 24.

The thermocouples 23, 24 have the thermoelectric material 10
A lead wire 25 made of a thermochemically stable material for thermoelectromotive force measurement is provided so as to contact the low temperature side contact portion and the high temperature side contact portion. A voltmeter 30 is interposed between the dedicated lead wires 25 for thermoelectromotive force measurement provided on both thermocouples 23 and 24, and the electromotive force of the thermoelectric material 10 is influenced by the thermocouples 23 and 24. It can be measured without.

The material of the lead wire 25 is, for example, A
It may be formed using a thermally and chemically stable material such as g, Pt, Au, and Cu. By providing the thermocouple electromotive force measurement lead wires 25 to the thermocouples 23 and 24, respectively, unlike the first and second embodiments, the thermocouple in a state in which the influence of the thermocouple-derived electromotive force is eliminated from the beginning. The thermoelectromotive force of the material can be measured.

The effectiveness of the thermoelectromotive force measuring method for the thermoelectric material based on the third embodiment described above was verified by the following experiments.

In the experiment, the thermoelectric material 1 having the structure shown in FIG.
As 0, a standard sample chromel constantan whose thermoelectromotive force value was already known was used. Heaters 13 and 14
A temperature difference of 4 ° C. was applied to the above standard sample, and the state of the electromotive force measured at each temperature with the lead wire 25 dedicated for thermoelectromotive force measurement in that state is shown by the value 310 (marked by ■) in FIG. . The value 300 shows a good agreement with the thermoelectromotive force (the value indicated by the broken line) of the standard sample described in the literature, and the method for measuring the thermoelectromotive force of the thermoelectric material proposed in the third embodiment is accurate. It was confirmed that it can be effectively used for measuring electromotive force of thermoelectric materials.

The present invention is not limited to the above-mentioned embodiments, but may be modified as necessary without departing from the scope of the invention.

For example, in the above description, the method of measuring the noise voltage derived from the thermocouple or canceling it by replacing the heater or the thermocouple has been described.
The low temperature side and the high temperature side of the thermoelectric material may be interchanged by rotating the thermoelectric material itself in the state where the thermocouple is provided.

[0065]

EFFECTS OF THE INVENTION According to the present invention, in measuring the electromotive force of a thermoelectric material, it is possible to eliminate the influence of noise voltage derived from a thermocouple. Can be measured.

[Brief description of drawings]

FIG. 1A is an explanatory view of relevant parts showing a state of an electromotive force measuring system of a thermoelectric material in a state where a temperature difference is applied, in relation to the measuring method shown in the first embodiment of the present invention; FIG. 4 is an explanatory view of a main part of the electromotive force measurement system shown in (A) in a state in which a temperature difference between thermoelectric materials is eliminated.

FIG. 2 is a diagram showing the effectiveness of the electromotive force measurement method described in the first embodiment.

FIG. 3A is an explanatory view of a main part of an electromotive force measuring system of a thermoelectric material in a state in which a temperature difference is provided, regarding a measuring method shown in a second embodiment of the present invention, and FIG. It is a principal part explanatory view of the electromotive force measurement system shown to (A) in the state which replaced the heater of the side and low temperature side.

FIG. 4 is a diagram showing the effectiveness of the electromotive force measurement method shown in the second embodiment.

5 (A) and 5 (B) are principal part explanatory views showing a modified example of the electromotive force measurement system.

FIG. 6 relates to a measuring method according to a third embodiment of the present invention,
It is a principal part explanatory drawing of the electromotive force measurement system which shows the structure which provided the lead wire for thermoelectromotive force measurement separately in the thermocouple for temperature measurement.

FIG. 7 is a diagram showing the effectiveness of the electromotive force measurement method shown in the third embodiment.

FIG. 8 is an explanatory diagram showing the configuration of a conventional thermoelectromotive force measuring system for thermoelectric materials.

[Explanation of symbols]

1 Thermoelectric material 2 heater 3 thermocouple 3a lead wire 4 thermocouple 4a lead wire 5 Voltmeter 10 thermoelectric materials 11 heater 12 heater 13 heater 14 heater 21 thermocouple 22 thermocouple 23 thermocouple 24 thermocouple 25 lead wire 30 voltmeter 110 value 120 values 130 values 210 value 220 value 230 value 310 value TE isothermal TH high temperature TL low temperature V Apparent electromotive force V1 Thermoelectric power derived from thermoelectric material V2 noise voltage

Claims (5)

[Claims] 1. An electromotive force between a high temperature side contact portion and a low temperature side contact portion is measured by a measuring system in which thermocouples are brought into contact with the high temperature side and the low temperature side of a thermoelectric material having a temperature difference. A thermoelectromotive force measuring method of a thermoelectric material for obtaining a thermoelectromotive force of the thermoelectric material, wherein a thermovoltage of the thermoelectric material is generated by removing from the electromotive force a noise voltage derived from the thermocouple which becomes noise generated by the thermocouple itself. A method for measuring a thermoelectromotive force of a thermoelectric material, characterized by obtaining electric power. 2. The thermoelectromotive force measuring method for a thermoelectric material according to claim 1, wherein a noise voltage derived from the thermocouple is generated between the high temperature side contact portion and the low temperature side contact portion in the measurement system. A method for measuring a thermoelectromotive force of a thermoelectric material, characterized by measuring the electric power as well as measuring the electric power. 3. The method for measuring thermoelectromotive force of a thermoelectric material according to claim 1 or 2, wherein the noise voltage derived from the thermocouple has a temperature difference between the high temperature side contact portion and the low temperature side contact portion of the thermoelectric material. In the measurement of the electromotive force between the thermoelectric material and the high temperature side contact portion of the thermoelectric material, a state without a temperature difference between the high temperature side contact portion and the low temperature side contact portion is generated at least once, and the electromotive force is maintained in that state. A method for measuring a thermoelectromotive force of a thermoelectric material, which is obtained by measuring 4. The thermoelectromotive force measuring method for a thermoelectric material according to claim 1, wherein the electromotive force between the high temperature side contact portion and the low temperature side contact portion of the thermoelectric material is measured by the high temperature side. The contact portion and the low temperature side contact portion are exchanged with each other and with no exchange, and by calculating an arithmetic mean value of electromotive force in the exchanged state and electromotive force in the non-exchanged state, A thermoelectromotive force measuring method for a thermoelectric material, wherein noise voltage derived from the thermocouple is removed from electromotive force between the high temperature side contact portion and the low temperature side contact portion of the thermoelectric material. 5. The method for measuring thermoelectromotive force of a thermoelectric material according to claim 1, wherein a lead wire for measuring electromotive force is attached to each of the thermocouples to be brought into contact with each of the low temperature side contact portion and the high temperature side contact portion. By providing separately from the one for measurement,
A thermoelectromotive force measuring method for a thermoelectric material, wherein the noise voltage derived from the thermocouple is excluded from the electromotive force generated between the high temperature side contact portion and the low temperature side contact portion of the thermoelectric material.