KR101690427B1

KR101690427B1 - Seebeck coefficient and electrical resistance measurement system

Info

Publication number: KR101690427B1
Application number: KR1020150131434A
Authority: KR
Inventors: 조성래; 반 쾅 웬; 안 투안 둥
Original assignee: 울산대학교 산학협력단
Priority date: 2015-09-17
Filing date: 2015-09-17
Publication date: 2016-12-27

Abstract

The present invention relates to an apparatus for measuring a Seebeck coefficient and an electrical resistance, and more particularly to an apparatus for measuring a Seebeck coefficient and an electrical resistance of a thermoelectric material in a temperature range of 77K to 1300K.

Description

{Seebeck coefficient and electrical resistance measurement system}

The Seebeck effect is a phenomenon in which an electromotive force is generated when a temperature difference is applied to both ends of a thermoelectric material. In the case of n-type semiconductors, when the temperature difference between both ends occurs, the electrons at the high temperature end have higher kinetic energy than the electrons at the low temperature end. By this thermal driving force, the electrons in the high-temperature stage are diffused to the low-temperature end in order to lower the energy. As the electrons move from the high temperature end to the low temperature end, the high temperature end is charged to (+) and the low temperature end is charged to (-), and a potential difference is generated between both ends. In this state, an electromotive force is generated to return the electrons back to the high-temperature end, and the carrier moves until the thermal driving force and the electromotive force become equal. This electromotive force is proportional to the temperature difference across the device. On the other hand, in the case of the p-type semiconductor, since the holes are the main carriers, the direction of the electromotive force is opposite to that of the n-type. A Seebeck coefficient is used to evaluate the properties of the thermoelectric material, and the Seebeck coefficient can be defined by the following equation.

[Equation 1]

S =? V /? T

That is, it can be seen that the Seebeck coefficient S is proportional to the change of the voltage V and inversely proportional to the change of the temperature T. Therefore, as a method for measuring the Seebeck coefficient of a thermoelectric material, a method of measuring a temperature and a voltage of a pair of points having different distances from the heating source by heating one side of the thermoelectric material is common .

However, existing Seebeck coefficient measurement devices are classified into devices for measurement at room temperature and high temperature and devices for measurement at low temperature.

It is an object of the present invention to provide a device capable of measuring the heat transfer coefficient of a thermoelectric material and its electrical resistance even in a high temperature range as well as a low temperature range.

In order to achieve the above object, the present invention provides a vacuum chamber comprising: a vacuum chamber having a sealed inner space and capable of forming a vacuum or high-pressure gas atmosphere in the inner space; A first space formed in the inner space of the vacuum chamber, a first space formed in the inner space of the vacuum chamber, an outer tube communicating with the outer tube so as to be larger in size than the inner tube, A cooling chamber having two spaces; A cooling medium inlet pipe installed to be connected to the second space of the cooling chamber and into which the cooling medium flows; A cooling medium discharge pipe installed to be connected to the second space of the cooling chamber and through which the cooling medium is discharged from the cooling chamber; A first metal block installed in a first space of the cooling chamber; A second metal block installed in a first space of the cooling chamber and spaced apart from the first metal block; A first heater installed in the first metal block or the second metal block and forming a temperature gradient; A second heater installed in the first space of the cooling chamber so as to surround the first metal block and the second metal block; A sample holder installed in the first space of the cooling chamber and on the top of the metal block, for supporting the sample; A first probe formed on the first metal block; A second probe formed on the second metal block; A third probe formed between the first metal block and the second metal block; A fourth probe formed between the first metal block and the second metal block and spaced apart from the third probe; And a first thermocouple and a second thermocouple installed in the first metal block and the second metal block for measuring a temperature gradient, respectively.

The apparatus for measuring a Seebeck coefficient and electrical resistance according to the present invention is characterized by being able to measure a Seebeck coefficient and an electrical resistance of a thermoelectric material in a temperature range of 77K to 1300K.

In the present invention, the cooling medium may be liquid nitrogen, high pressure gas, or water.

In the present invention, the outlet of the cooling medium inlet pipe and the inlet of the cooling medium outlet pipe may respectively be disposed at the upper end of the second space.

In the present invention, the second heater may be a hollow cylindrical cylinder heater.

In order to measure the electrical resistance in the present invention, the first probe and the second probe among the first probe, the second probe, the third probe and the fourth probe apply a current, and the remaining third probe and the fourth probe apply a voltage Can be measured.

In order to measure the Seebeck coefficient in the present invention, the first thermocouple and the second thermocouple measure the temperature gradient of the sample, and the first probe and the second probe can measure the voltage.

In the present invention, the first thermocouple and the second thermocouple may be serially connected to the same electrode to measure the temperature gradient.

In the present invention, the third probe and the fourth probe are vertically movable.

The apparatus according to the present invention comprises: a lifting plate for supporting a third probe and a fourth probe, respectively; And a lifting / lowering screw for screwing the lifting steel plate and lifting the lifting steel plate by rotation.

An apparatus according to the present invention includes: a first support installed at a lower portion of a vacuum chamber; A sealing member sealing between the vacuum chamber and the first support; A first engaging member for engaging the vacuum chamber and the first support; A vacuum pump connected to the vacuum chamber; A heater, a probe, and a multi-pin connected to the thermocouple.

The apparatus according to the present invention comprises: a second support block installed at a lower portion of the first metal block and the second metal block in the first space of the cooling chamber; An insulator provided between the first metal block and the second metal block and the second support; A second engaging member for engaging the cooling chamber and the second support; A third thermocouple and a fourth thermocouple installed in the second heater and the second support, respectively; A first cap which is openably and closably installed at an upper end of the cooling chamber; And a second cap which is openably and closably provided on an upper end of the second support.

An apparatus according to the present invention includes: a guide member installed on an upper portion of a second support; A guide member provided between the second cap and the sample holder and having a guide hole into which the upper end of the guide member is inserted, and may further include a compression member for compressing the sample holder.

The apparatus according to the present invention is provided with a cooling chamber and a cylinder heater, so that it is possible to measure a Seebeck coefficient and an electrical resistance of a thermoelectric material in a low-temperature range as well as a high-temperature range.

1 is a cross-sectional view showing the overall configuration of a device for measuring a Seebeck coefficient and an electric resistance according to the present invention.
FIG. 2 is a cross-sectional view showing internal components installed inside a cooling chamber of a Seebeck coefficient and electric resistance measuring apparatus according to the present invention.
FIG. 3 is a cross-sectional view illustrating internal components installed inside a cooling chamber of a device for measuring the electrical resistance and the Seebeck coefficient according to the present invention.
4 is a top plan view of internal components installed inside the cooling chamber of the device for measuring the electrical resistance and the Seebeck coefficient according to the present invention.
5 is a graph of the temperature change versus voltage change measured in accordance with the present invention.
Figure 6 is a graph of current versus voltage measured in accordance with the present invention.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a cross-sectional view showing an overall configuration of a device for measuring a Seebeck coefficient and an electrical resistance according to the present invention, and FIG. 2 is a cross-sectional view showing internal components installed inside a cooling chamber of a Seebeck coefficient and electric resistance measuring apparatus according to the present invention FIG. 3 is a cross-sectional view showing internal components installed inside the cooling chamber of the apparatus for measuring the electrical resistance and the Seebeck coefficient according to the present invention, and FIG. 4 is a cross- Fig. 5 is a plan view of the internal parts installed inside.

1 to 4, the apparatus for measuring a Seebeck coefficient and electrical resistance according to the present invention includes a first support 10, a multi-fin 11, a vacuum chamber 20, an internal space 21, 22, the sealing member 23, the vacuum pump 24, the cooling chamber 30, the first cap 31, the first space 32, the inner tube 33, the second space 34, The cooling medium inlet pipe 36, the cooling medium outlet pipe 37, the second support member 40, the second coupling member 41, the third thermocouple 42, the second cap 43, the second heater 50, the fourth thermocouple 51, the first metal block 60, the second metal block 61, the first heater 62, the insulator 63, the first probe 70, the second probe 71 A third probe 72, a fourth probe 73, a lift plate 74, a lift control screw 75, a sample holder 80, a sample 81, a first thermocouple 82, (83), a compression member (90), a guide member (91), and the like. All parts are suitable for low temperature and high temperature ranges and can be made of stable materials.

The first support 10 is installed at a lower portion of the vacuum chamber 20 to support the vacuum chamber 20. The first support 10 may be composed of a top plate and a plurality of legs supporting the top plate.

The multi-fin 11 is installed on the first support 10 and connected to the heaters 50, 62, the probes 70, 71, 72, 73 and the thermocouples 42, 51, 82, And connects them to the outside.

The vacuum chamber 20 is installed above the first support 10 and has a sealed inner space 21. Vacuum formation is possible in the inner space 21. On the other hand, some materials may be evaporated due to the high temperature measurement, and an inert gas atmosphere having a high pressure inside the vacuum chamber 20 may be formed for increasing the evaporation temperature or for other purposes. When a vacuum is formed in the vacuum chamber 20, the cooling efficiency can be improved and the cooling rate can be increased.

The first coupling member 22 serves to couple the first support 10 to the vacuum chamber 20, and for example, a screw coupling member or the like can be used.

The sealing member 23 serves to seal the first support 10 and the vacuum chamber 20, and rubber o-rings, for example, can be used.

The vacuum pump 24 may be connected to the vacuum chamber 20 to form a vacuum in the inner space 21 of the vacuum chamber 20.

The cooling chamber 30 is installed in the inner space 21 of the vacuum chamber 20 and includes a first cap 31, a first space 32, an inner cylinder 33, a second space 34, an outer cylinder 35 And the like.

The first cap 31 may be installed at the top of the cooling chamber 30 to be openable and closable. The first cap 31 may also function to prevent heat radiation to the outside.

The first space 32 is an inner space of the inner cylinder 33 formed inside the inner cylinder 33 and can be sealed by the first cap 31.

The inner tube 33 may be formed, for example, in a cylindrical shape. The upper portion of the inner cylinder 33 can be opened and closed by the first cap 31. [

The outer tube 35 is larger in diameter (diameter) than the inner tube 33 and can be connected to be sealed with the inner tube 33. The outer tube 35 may be formed, for example, in a cylindrical shape.

The second space 34 can receive the cooling medium as a sealed space formed between the inner cylinder 33 and the outer cylinder 35.

A hole for connecting a wire or the like to the outside may be formed in the lower center of the inner tube 33 and the outer tube 35, and the hole may be sealed by the second support 40.

The cooling medium inlet pipe 36 is installed so as to be connected to the second space 34 of the cooling chamber 20 through the cooling chamber 30 so that the cooling medium can be introduced into the cooling chamber 30.

The cooling medium discharge pipe 37 is installed to be connected to the second space 34 of the cooling chamber 20 through the cooling chamber 30 through which the cooling medium can be discharged from the cooling chamber 30. [

The outlet of the cooling medium inlet pipe 36 and the inlet of the cooling medium outlet pipe 37 may be arranged at the upper end of the second space 34 respectively as shown in Figure 1 so that the cooling medium flows into the cooling chamber 30 ), So that the cooling efficiency can be improved. If the heights of the outlet of the cooling medium inlet pipe 36 and the inlet of the cooling medium outlet pipe 37 are low, the cooling medium can escape without staying in the cooling chamber 30 for a short time.

As the cooling medium, liquid nitrogen, high-pressure gas, water or the like can be used, and liquid nitrogen can be preferably used. When water is used, it can be measured from room temperature to high temperature, and when liquid nitrogen is used, it can be measured to a cryogenic temperature of about 77K. When heated to a high temperature, liquid nitrogen can be removed in advance.

In the present invention, by using the cooling chamber 30 and using liquid nitrogen as the cooling medium, the Seebeck coefficient and electrical resistance can be measured up to a cryogenic temperature of about 77K.

The second support platform 40 may be installed in the first space 32 of the cooling chamber 30 and may comprise a plurality of bridges connecting the upper and lower plates and the two plates as illustrated in the figure.

The second engaging member 41 serves to engage the cooling chamber 30 and the second support 40. For example, a screw coupling member or the like may be used.

The third thermocouple 42 may be inserted into the leg of the second support 40 and measure the ambient temperature. The temperature measured by the third thermocouple 42 may be used as the reference temperature.

The second cap 43 may be installed at the upper end of the second support 40 to be openable and closable. Metal blocks 60 and 61 and a sample 81 may be installed in a closed space formed by the second support platform 40 and the second cap 43.

The second heater 50 is installed in the first space 32 of the cooling chamber 30 and is installed so as to surround the first metal block 60 and the second metal block 61 and the sample 81. The second heater 50 may preferably be a hollow cylindrical cylinder heater. By constituting the second heater 50 with the cylinder heater, it is possible to uniformly heat the metal blocks 60 and 61 and the sample 81 to reduce the measurement error and improve the accuracy, The Seebeck coefficient and electrical resistance can be measured up to a high temperature of about 1300K. The second heater 50 may be used to raise the ambient temperature.

In order to adjust the ambient temperature, a PID (Proportional Integral Derivative) temperature controller connected to the second heater 50 and the cooling chamber 30 may be installed. Heating and cooling of the sample 81 can be simultaneously performed by the second heater 50 and the cooling chamber 30, and the entire sample temperature can be easily controlled by the PID temperature controller.

The fourth thermocouple 51 can be installed in the second heater 50 and can measure the ambient temperature and the temperature of the second heater 50 and the like.

The first metal block 60 may be installed in the first space 32 of the cooling chamber 30 and may be installed on the second support 40.

The second metal block 61 is installed in the first space 32 of the cooling chamber 30 and is spaced apart from the first metal block 60 by a predetermined distance, .

Each of the first and second metal blocks 60 and 61 has a first thermocouple 82 and a second thermocouple 83 for measuring the temperature gradients of the two metal blocks 60 and 61 and / Can be installed. The first thermocouple 82 and the second thermocouple 83 may be installed in the first metal block 60 and the second metal block 61 respectively and may be connected in series to the same electrode for measuring the temperature gradient . The first thermocouple to the fourth thermocouple can be stably connected to the support 40 to provide an accurate value of the temperature in the low temperature range and the high temperature range.

To measure the Seebeck coefficient, the first thermocouple 82 and the second thermocouple 83 measure the temperature gradient of the sample, and the first probe 70 and the second probe 71 can measure the voltage.

The first heater 62 may be installed in the first metal block 60 or the second metal block 61 to form a temperature gradient in the metal blocks 60 and 61 and / The first heater 62 may be designed to have a sufficiently large resistance while minimizing the size and thermal radiation to the outside, and may be inserted into the metal block. The first heater 62 may be shielded with a metal foil or the like to block heat radiation.

The insulator 63 is provided between the second support base 40 and the metal blocks 60 and 61 to insulate them from each other. The insulator 63 may be formed in a plate shape.

The first probe 70 may be formed on the first metal block 60 and the second probe 71 may be formed on the second metal block 61.

The third probe 72 may be installed between the first metal block 60 and the second metal block 61.

The fourth probe 73 may be disposed between the first metal block 60 and the second metal block 61 and spaced apart from the third probe 72 by a predetermined distance.

As described above, in the present invention, the electric resistance can be measured using a linear four-point probe and a Van der Pauw method. Specifically, the first probe 70 and the second probe 71 of the first probe 70, the second probe 71, the third probe 72 and the fourth probe 73 apply a current, The remaining third probe 72 and the fourth probe 73 measure the voltage, and the electric resistance can be obtained from the current and the voltage.

The conventional two-probe structure has a problem in that contact resistance is generated according to the contact strength, but in the case of the four-probe structure, there is an advantage that the contact resistance can be removed.

The ohmmeter can be used to check the ohmic contact first, and then verify the current and voltage. The ammeter can be connected in series, and the voltmeter can be connected in parallel.

Only the first probe 70 and the second probe 71 may be used while the third probe 72 and the fourth probe 73 may not be used. Four probes are available for electrical resistance measurement.

It is possible to easily change from the four probe structure to the two probe structure by separating the central probes 72 and 73 or changing the external contact.

The third probe 72 and the fourth probe 73 are vertically movable by the lifting plate 74 and the lifting and adjusting screw 75 so that the probes 72 and 73 and the sample 81 Contact and the like can be ensured, and they may not be affected by the high temperature.

The lifting plate 74 is coupled to the third probe 72 and the fourth probe 73 and supports the lifting plate 74 and the fourth lifting plate 74, respectively, and can be lifted up and down by the lifting and lowering adjusting screw 75.

The lift adjusting screw 75 is screwed with the lift plate 74 and can lift and lift the lift plate 74 by rotation. That is, the lift plate 74 can be raised and lowered in the vertical direction by turning the lift adjusting screw 75. The elevating and lowering adjusting screws 75 may be provided on the lifting plate 74 as a plurality of bolts 75a and 75b.

The sample holder 80 is installed on the first space 32 of the cooling chamber 30 and the metal blocks 60 and 61 and serves to support the sample 81. The sample holder 80 may be made of an insulator.

A sample 81 is placed on top of the metal blocks 60 and 61 and can be supported by the sample holder 80. The sample 81 can be assembled and installed very easily due to the horizontal geometry of the measuring device.

The compression member 90 is provided between the second cap 43 and the sample holder 80 and serves to compress the sample holder 80 to improve the contact between the metal blocks 60 and 61 and the sample 81 do. The compression member 90 can be engaged with the guide member 91, and a guide hole through which the upper end of the guide member 91 is inserted can be provided at the lower portion.

The guide member 91 may be engaged with the compression member 90 to guide the guide member 91. The guide member 91 may be provided on the second support 40 and may have a long bar shape and may be installed on the lift plate 74 as a plurality of pieces 91a and 91b.

Further, a plurality of voltmeters (not shown) can be used to measure the thermoelectric voltage and the temperature gradient between two points of the sample 81, and a computer (not shown) can be used to control each component and display, Not shown) can be used.

Figure 5 is a graph of the temperature change versus voltage change measured using the apparatus according to the present invention, showing the thermoelectric voltage as a function of the temperature gradient measured at 533K, where the slope is the Seebeck coefficient. The slope is a nearly complete straight line, indicating that the measurement error is very small.

Figure 6 is a graph of current versus voltage measured using an apparatus in accordance with the present invention showing the voltage as a function of the current measured at 300K where the slope is the electrical resistance.

The device according to the present invention is capable of measuring the Seebeck coefficient and electrical resistance in the low and high temperature ranges, measuring the thickness and bulk of the sample in a variety of sizes and shapes, which is simple to operate, easy to change the sample, Lt; / RTI >

The device according to the present invention can be applied to a semiconductor material and can be applied to, for example, a coolant of a sheet in a vehicle, a coolant of a water purifier, a semiconductor field, and the like. In addition, although the conventional apparatus is installed horizontally, the apparatus of the present invention is vertically installable. In addition, the existing equipment was expensive more than 100 million won, but the device of the present invention can be manufactured to 10 million yen or less.

The present invention relates to a vacuum cleaner and a method of manufacturing the vacuum cleaner, and more particularly, to a vacuum cleaner comprising a vacuum cleaner, a vacuum cleaner, and a vacuum cleaner. A first space 33 a inner tube 34 a second space 35 an outer tube 36 a cooling medium inlet tube 37 a cooling medium outlet tube 40 a second support member 41 a second coupling member 42 a third thermocouple A first heater and a second heater are arranged in parallel to each other so that the first and second probes are connected in parallel to each other. A second probe, 72: a third probe, 73: a fourth probe, 74: a lift plate, 75: a lift adjustment screw, 80: a sample holder, 81: a sample, 82: a first thermocouple, 83: a second thermocouple, 90 : Compression member, 91: guide member

Claims

A vacuum chamber having a sealed inner space and capable of forming a vacuum or high-pressure gas atmosphere in the inner space;
A first space formed inside the inner cylinder of the vacuum chamber, a first space formed inside the inner cylinder, an outer cylinder connected to the outer cylinder so as to be larger in size than the inner cylinder and sealed so as to pass through, A cooling chamber having two spaces;
A cooling medium inlet pipe installed to be connected to the second space of the cooling chamber and into which the cooling medium flows;
A cooling medium discharge pipe installed to be connected to the second space of the cooling chamber and through which the cooling medium is discharged from the cooling chamber;
A first metal block installed in a first space of the cooling chamber;
A second metal block installed in a first space of the cooling chamber and spaced apart from the first metal block;
A first heater installed in the first metal block or the second metal block and forming a temperature gradient;
A second heater installed in the first space of the cooling chamber so as to surround the first metal block and the second metal block;
A sample holder installed in the first space of the cooling chamber and on the top of the metal block, for supporting the sample;
A first probe formed on the first metal block;
A second probe formed on the second metal block;
A third probe formed between the first metal block and the second metal block;
A fourth probe formed between the first metal block and the second metal block and spaced apart from the third probe;
And a first thermocouple and a second thermocouple installed in each of the first metal block and the second metal block to measure a temperature gradient.

The method according to claim 1,
Wherein the anti-shear coefficient and the electric resistance of the thermoelectric material can be measured in a temperature range of 77K to 1300K.

The method according to claim 1,
Wherein the cooling medium is liquid nitrogen, high pressure gas, or water.

The method according to claim 1,
Wherein the outlet of the cooling medium inlet pipe and the inlet of the cooling medium outlet pipe are disposed at the upper end of the second space, respectively.

The method according to claim 1,
And the second heater is a hollow cylinder-shaped cylinder heater.

The method according to claim 1,
Wherein a first probe and a second probe among the first probe, the second probe, the third probe and the fourth probe apply a current, and the remaining third probe and the fourth probe measure a voltage. Resistance measuring device.

The method according to claim 1,
Wherein the first thermocouple and the second thermocouple measure the temperature gradient of the sample and the first probe and the second probe measure the voltage.

The method according to claim 1,
Wherein the first thermocouple and the second thermocouple are serially connected to the same electrode for measuring the temperature gradient.

The method according to claim 1,
Wherein the third probe and the fourth probe are movable in the vertical direction.

10. The method of claim 9,
A lift plate for supporting the third probe and the fourth probe, respectively; And an elevating and lowering screw for screwing the elevating plate and lifting the elevating plate by rotation.

The method according to claim 1,
A first support provided at a lower portion of the vacuum chamber;
A sealing member sealing between the vacuum chamber and the first support;
A first engaging member for engaging the vacuum chamber and the first support;
A vacuum pump connected to the vacuum chamber;
And a plurality of fins provided on the first support and connected to the respective heaters, the probe, and the thermocouple.

The method according to claim 1,
A second support installed at a lower portion of the first metal block and the second metal block in the first space of the cooling chamber;
An insulator provided between the first metal block and the second metal block and the second support;
A second engaging member for engaging the cooling chamber and the second support;
A third thermocouple and a fourth thermocouple installed in the second heater and the second support, respectively;
A first cap which is openably and closably installed at an upper end of the cooling chamber;
And a second cap that is openably and closably provided on an upper end of the second support.

13. The method of claim 12,
A guide member provided on an upper portion of the second support;
And a guide member which is provided between the second cap and the sample holder and into which the upper end of the guide member is inserted, further comprising a compression member for compressing the sample holder.