JP2003234515A - Thermoelectric module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermoelectric module that can be easily manufactured, can reduce thermal resistance between an electrode or a thermoelement, and an external heat-exchanging member, can improve heat efficiency, can arrange the thermoelectric element with high density, and can improve thermoelectric characteristics to external dimensions. <P>SOLUTION: In a thermoelectric module 20 where thermoelectric elements Ep and En are directly connected, an insulating material is flame-sprayed to the contact surface with an external heat exchanging member to form coating 21. Additionally, in a thermoelectric module 50, an insulating material is flame- sprayed to the opposite surfaces of the adjacent thermoelectric elements Ep and En to form coating 51. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a thermoelectric module in which a plurality of thermoelectric elements are electrically connected.

[0002]

2. Description of the Related Art For example, a thermoelectric module as shown in FIG. 6 is adopted as a heating / cooling means in a semiconductor manufacturing facility, a temperature adjusting device for a laser diode for optical communication, or a power generating means in a thermoelectric generator.

In this thermoelectric module A, a large number of thermoelectric elements (P type thermoelectric elements) Ep and thermoelectric elements (N type thermoelectric elements) En are alternately dispersed and arranged, and adjacent thermoelectric elements E are arranged.
The p and the thermoelectric element En are electrically connected to each other via electrode plates D, D ... Which are made of Cu (copper) which is a highly conductive material.

The thermoelectric elements Ep, En, ... Are arranged with a gap or insulated so that they do not come into electrical contact with adjacent thermoelectric elements outside the desired electrical connection. It is housed in a thermoelectric element holder that is made of a material and can partition adjacent thermoelectric elements.

The electrode plates D, D ... Are brazed to the thermoelectric elements Ep, En by solder F, and an external heat exchange member (not shown) on the opposite side of the thermoelectric elements. On the contact surface with the ceramic plate materials B, B for electrical insulation between the thermoelectric elements and electrodes and the external heat exchange member.
It is brazed with a brazing material or solder C.

On each of the thermoelectric elements Ep and En, a diffusion prevention layer (intermediate layer) G is formed by Ni (nickel) plating or the like for the purpose of preventing the diffusion of the solder component into the thermoelectric elements.

Here, the above-mentioned electrode plates D, D ...
Needless to say, it also functions as a bonded body that electrically connects the adjacent thermoelectric elements Ep and En to each other and mechanically connects the adjacent thermoelectric elements Ep and En to each other.

Further, in the thermoelectric module in which the insulating materials B, B ... Are not joined to the electrode plates D, D ... As described above, an insulating material such as a ceramic plate material or a mica foil is used as described above. It is used in a state of being sandwiched between the electrode plates D, D ... And the external heat exchange member.

[0009]

By the way, in the above-mentioned conventional thermoelectric module A, when a ceramic plate material is used as the insulating material, since the ceramic material is brittle, it is necessary to increase the thickness of the plate material in order to give it strength. is there. For example, when inexpensive and highly insulating, thermally conductive, and highly heat-resistant alumina ceramics are used by being joined to the electrodes of the thermoelectric module, or when being used between the electrodes of the thermoelectric module and the external heat exchange member, Usually, the thickness of the alumina ceramic plate material needs to be 0.5 mm or more in consideration of its strength.

However, if the thickness of the alumina ceramics is large, the thermal resistance of the insulating material portion between the thermoelectric module or the electrodes of the thermoelectric module and the external heat exchange member becomes high, and therefore the thermoelectric element and the external heat exchange member. It is not preferable because the heat transfer property between and is lowered.

On the other hand, although mica can be formed thinner than alumina ceramics, its thermal conductivity is much lower than the effect of reducing its thickness, and its thermal conductivity is poor.

In order to braze the ceramic plate to the electrodes of the thermoelectric module with solder or brazing material,
It is necessary to perform a step of previously performing metallization treatment of an electrode pattern on the surface of the ceramic plate. Further, when the ceramic plate is joined to the thermoelectric module, since the linear expansion coefficient of the ceramic is smaller than that of Cu or the like of the electrode member, a large thermal stress is generated inside the thermoelectric module according to the temperature change depending on the thickness of the ceramic plate. Therefore, it is necessary to take mitigation measures.

Further, the linear expansion coefficient of the electrode is different from that of the insulating material. Therefore, when an insulating material such as a ceramic plate is used by sandwiching it between the electrode of the thermoelectric module and the external heat exchange member, different deformation occurs between the electrode and the insulating material due to temperature change, and the insulating material The heat contact area with the material is reduced, and the heat transfer property is reduced.

The present invention has been made in view of the above circumstances, and is a thermoelectric module in which an insulating material is joined to a thermoelectric element, which can be easily manufactured and handled, and the workability of various operations can be improved. Moreover, it is possible to provide a thermoelectric module that reduces thermal resistance of an insulating portion between the thermoelectric element and an external heat exchange member and improves thermal contact between the thermoelectric element and an insulating material to improve thermal efficiency. The purpose of 1.

Further, the thermoelectric module preferably has high thermoelectric characteristics. One of the methods for improving the thermoelectric properties is to arrange the thermoelectric elements at a high density so that the contact area between the thermoelectric elements and the electrodes is as large as possible. However, if the thermoelectric elements are arranged at a high density, there is a risk that adjacent thermoelectric elements will contact each other. Since securing insulation between thermoelectric elements is prioritized over improving thermoelectric characteristics, an appropriate gap is provided between each thermoelectric element, or a holder with an appropriate thickness allows each thermoelectric element to It is partitioned. Therefore, the thermoelectric characteristics of the thermoelectric module have a limit according to the external dimensions.

The present invention has been made in view of the above circumstances, and it is a second object of the present invention to provide a thermoelectric module in which thermoelectric elements can be arranged at high density and thermoelectric characteristics with respect to external dimensions can be improved. The purpose of.

[0017]

[Means and Effects for Solving the Problems] Then, the first
The invention is a thermoelectric module in which a plurality of thermoelectric elements are electrically connected to each other, wherein at least a part of the thermoelectric elements has a film formed by thermal spraying of an insulating material.

A second invention is characterized in that, in the first invention, a surface of the thermoelectric element facing the external heat exchange member has a film formed by thermal spraying of an insulating material.

According to the first and second aspects of the invention, the thermoelectric module has adjacent thermoelectric elements connected to each other and the insulating material is joined to the contact surface with the external heat exchange member. It is possible to obtain a thermoelectric module that can be easily manufactured by directly bonding the insulating material and the thermoelectric module by thermal spraying without performing the above. Further, since the thermoelectric element and the insulating material are integrated, the thermoelectric module and the insulating material can be easily handled, and a thermoelectric module that can improve workability of various operations can be obtained.
Furthermore, since a film of an insulating material having a desired thickness can be formed by thermal spraying, reducing the thickness of the insulating material can reduce the thermal resistance of the insulating material portion between the external heat exchange member and
Further, since the thermoelectric element and the insulating film are directly joined, the thermal contact between the thermoelectric element and the insulating material is improved, and these can improve the heat transfer between the thermoelectric element and the external thermoelectric exchange member. You can get the module. Also, since a film of an insulating material having a desired thickness can be obtained,
By selecting an appropriate thickness, the thermal stress generated inside the thermoelectric module due to temperature changes can be suppressed to a minimum. Therefore, it is possible to obtain a thermoelectric module in which damage due to thermal stress is prevented and heat resistance and durability are improved.

A third invention is characterized in that, in the first invention, a surface of the thermoelectric element facing the adjacent thermoelectric element has a film formed by thermal spraying of an insulating material.

According to the first and third aspects of the invention, since the coating film of the insulating material is formed on the opposing surfaces of the adjacent thermoelectric elements, even if a plurality of thermoelectric elements are arranged without providing a gap portion, the thermoelectric elements can be arranged. Can be prevented from making electrical contact with each other outside the desired electrical connection part, which makes it easy to manufacture without making a thermoelectric element holder, and allows the thermoelectric element modules to be arranged in high density. It is possible to obtain a thermoelectric module capable of improving thermoelectric characteristics with respect to dimensions.

[0022]

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

The present invention focuses on the ease of thermal spraying and the usefulness of a coating formed by thermal spraying. Therefore, a technique as a reference of the present invention will be described as a first embodiment.

[Reference Technology] FIG. 1 shows a thermoelectric module according to a first embodiment of the present invention.
In No. 0, a large number of thermoelectric elements (P-type thermoelectric elements) Ep and thermoelectric elements (N-type thermoelectric elements) En are alternately dispersed and arranged, and adjacent thermoelectric elements Ep and thermoelectric elements En are arranged in the electrode plate 1.
1 electrically and mechanically connected to each other.

Each of the thermoelectric elements Ep and En is plated with Ni (nickel) for the purpose of preventing diffusion of the components of the solder 12 for joining the thermoelectric element and the electrode plate 11 into the thermoelectric element. The diffusion prevention layer 14 is formed.

Incidentally, the thermoelectric element Ep (P-type thermoelectric element)
Is an Sb-Te (antimony-tellurium) -based thermoelectric element. Further, the thermoelectric element En (N-type thermoelectric element) is Bi-
It is a Te (bismuth-tellurium) -based thermoelectric element.

Each of the electrode plates 11 is made of Cu (copper), and an insulating material is sprayed on the contact surface side of each of the electrode plates 11 with the external heat exchange member (not shown). The film 13 is formed.

As the insulating material forming the insulating film 13, a material having high thermal conductivity such as alumina ceramics is preferable.

Incidentally, the insulating material film 13 formed by thermal spraying can be thinly formed to a thickness of about 0.05 (mm). Is the minimum thickness necessary to be satisfied as. However, as a matter of course, the insulating material film 13 is
From the viewpoint of insulation, it is necessary to form the thermoelectric elements Ep and En to a thickness that can withstand the maximum voltage applied or generated.

Therefore, in this embodiment, the thermoelectric element Ep,
Even when the maximum voltage is applied to En or generated, the above-mentioned insulating material is sprayed so that the film 13 has a thickness that functions as an insulating material.

As described above, the thickness of the insulating material film 13 can be changed according to the voltage value. (1) The insulating material is provided on the upper surface of the electrode plate 11 (contact surface with the external heat exchange member). In the case of a single ceramic plate, the point that the film is formed by thermal spraying and (2) the film 13 of the insulating material by thermal spraying is formed integrally with the electrode plate 11 and supported by the electrode. The mechanical strength is also greatly improved compared to the above, and as a result, the film is thinned to the thickness corresponding to the withstand voltage.

Therefore, for example, the maximum voltage value V of the applied or generated voltage is set to V1 (V) and V2 (V), and the thickness t of the film of the insulating material corresponding to each voltage value is 0.1. (Mm) and 0.2 (mm), in the present embodiment, in the thermoelectric module in which the voltage value V is V1 (V), the thickness t of the film of the insulating material formed by thermal spraying is used. It can be set to 0.1 (mm), while it can be set to 0.2 (mm) in the thermoelectric module used when the voltage value V is V2 (V).

On the other hand, in the case of the above-mentioned prior art, since a single ceramic plate is used, from the viewpoint of insulation, for example, in the thermoelectric module used at a voltage value V of V1 (V), 0.1 is used. (Mm) thickness ceramic plate, and in the case of a thermoelectric module used at a voltage value V of V2 (V), even if the ceramic plate thickness of 0.2 (mm) is good, the mechanical strength From the viewpoint (because the material is fragile), it was necessary to use a ceramic plate having a thickness of 0.5 (mm) or more.

In the above embodiment, the high temperature side and the low temperature side of the thermoelectric module (upper side and lower side in FIG. 1).
Although the coating 13 of the insulating material is formed on any of the electrode plates 11 of the above, the present invention is not limited to this.
The insulating material film 13 may be formed only on either the high temperature side or the low temperature side (the same applies to the second to fourth embodiments described later).

As described above, according to this embodiment,
Since it is possible to form the film 13 of the insulating material having a desired thickness (thinner compared to the conventional one) according to the voltage value in the thermoelectric module 10, the electrode plate 11 of the thermoelectric module 10 and the external heat exchange member. It is possible to reduce the thermal resistance of the insulating material portion between and, and to improve the heat conductivity between the thermoelectric element and the external heat exchange member.

Since the electrode plate 11 and the insulating material film 13 are integrated, the electrode plate 11 and the insulating material film 13 are integrated.
It is possible to improve the thermal contact between the thermoelectric element and the external heat exchanging member.

Furthermore, since the coating 13 of the insulating material integrated with the electrode plate 11 is formed by spraying the insulating material, the "step of subjecting ceramics to metallizing treatment" as in the prior art is performed. The thermoelectric module can be easily manufactured (improvement of working efficiency) without having to be incorporated in the process of manufacturing the thermoelectric module.

The present invention is based on the above-mentioned thermoelectric element material,
It is not limited to the diffusion prevention layer material, the method for forming the diffusion prevention layer, the electrode material, the method for joining the electrode and the thermoelectric element or the diffusion prevention layer, and the like. For example, a layer of a material having a linear expansion coefficient intermediate between those of the electrode plate 11 and the insulating material film 13 is provided. Then, the film 13 of the insulating material is applied to the electrode plate 11.
It is possible to suppress the thermal stress generated in the thermoelectric module due to the temperature change, as compared with the case where the thermal stress is directly formed. (The same applies to the second to fourth embodiments described later).

The technique of spraying an insulating material onto the electrodes of a thermoelectric module is described in "Thermoelectric Conversion Symposium 2000 (TEC2
000) Proceedings (Thermoelectric conversion research group), pp. 50-51 "
It is described in.

[Second Embodiment] FIG. 2 is a schematic side view showing a second embodiment of the thermoelectric module according to the present invention.

In FIG. 2, the thermoelectric module 20 is
A large number of thermoelectric elements (P-type thermoelectric elements) Ep and thermoelectric elements (N-type thermoelectric elements) En are alternately dispersed and arranged, and
Adjacent thermoelectric elements Ep and En are directly electrically connected to each other.

The thermoelectric element Ep (P type thermoelectric element) and the thermoelectric element En (N type thermoelectric element) are respectively the above-mentioned first
The thermoelectric element is the same as that in the above embodiment, but the present invention is not limited to this.

By the way, the thermoelectric elements Ep and En are directly bonded to each other as follows, for example. First, P on the mold
A certain amount of the thermoelectric element material powder is put in such a manner that the surface becomes flat. On top of that, a certain amount of N-type thermoelectric element material powder is put so that the surface becomes flat. This is alternately and repeatedly laminated, and when the desired number of layers is obtained, the whole is directly hot pressed and sintered. The laminate of the P-type thermoelectric element material and the N-type thermoelectric element material thus produced is cut according to the width and height of the thermoelectric element portion in the thermoelectric module. Finally, the cutouts 22 are provided alternately in the P-type thermoelectric material portion and the N-type thermoelectric material portion of the laminated body. In this way, the L-type P-type thermoelectric element and the N-type thermoelectric element are joined together.

Further, each of the thermoelectric elements Ep and En is formed in an L shape, but the present invention is not limited to this, and adjacent thermoelectric elements Ep and En are electrically connected to each other. External heat exchange member (not shown)
The shape thereof does not matter as long as it is formed so as to sufficiently secure a surface that is thermally connected to and.

Also in the second embodiment, the contact surface side of the thermoelectric elements Ep, En with the external heat exchange member is insulated by spraying an insulating material, as in the case of the first embodiment. A material film 21 is formed. As the insulating material forming the film 21 of the insulating material, a material having high thermal conductivity such as alumina ceramics is preferable.

In the structure of such a thermoelectric module 20, only the film 21 of the insulating material is interposed between the thermoelectric elements Ep and En and the external heat exchange member, and in the case of the first embodiment described above. No electrodes are interposed. For this reason,
The distance between the thermoelectric elements Ep and En and the external heat exchange member is shorter than that in the case of the first embodiment.

In the second embodiment described above, the coating 21 of the insulating material is formed on both the thermoelectric elements Ep and En on the high temperature side and the low temperature side (the upper side and the lower side in FIG. 2) of the thermoelectric module. However, the present invention is not limited to this, and the insulating material film 21 may be formed only on either the high temperature side or the low temperature side, as described above. According to the second embodiment, since no electrode is interposed between the thermoelectric element and the external heat exchange member, the thermoelectric elements Ep, En and the external heat exchange member are different from each other as compared with the case of the first embodiment. The distance between them can be shortened. Therefore, in the second embodiment, the following operational effects are exhibited.

That is, as compared with the case of the first embodiment, the thermoelectric element E of the thermoelectric module 20 is further enhanced.
The thermal resistance between p and En and the external heat exchange member can be reduced, and the heat transfer between the thermoelectric element and the external heat exchange member can be improved.

Further, since the insulating material film 21 integrated with the thermoelectric module 20 is formed by spraying the insulating material, a step of metallizing the ceramics as in the prior art is incorporated into the manufacturing step of the thermoelectric module. There is no need, and the thermoelectric module can be easily manufactured (work efficiency can be improved).

Furthermore, since the insulating material between the thermoelectric element and the external heat exchange member and the thermoelectric module are integrated, the thermoelectric module and the insulating material can be easily handled and the workability of various operations can be improved. A thermoelectric module can be obtained.

[Third Embodiment] FIG. 3 is a side view showing a thermoelectric module according to a third embodiment of the present invention.

The thermoelectric module 30 shown in FIG.
In the configuration of the thermoelectric module 10 of the first embodiment shown in (1), the coating 31 is added. Also,
The coating 31 may be added to the configuration of the thermoelectric module 20 of the second embodiment. Note that, in FIG. 3, parts having the same functions as those of the constituent elements shown in FIG. 1 are designated by the same reference numerals.

The coating film 31 is formed on the upper surface of the coating film 13 formed by thermal spraying of the insulating material, that is, on the contact surface side with the external heat exchange member (not shown) on the side opposite to the thermoelectric element, and as a base for brazing. It is formed by spraying the material (material that is easy to braze). The film 31 formed by this thermal spraying is brazed to the external heat exchange member. Note that copper (C
u), nickel (Ni) and the like.

Here, the brazing includes brazing at a high temperature exceeding 450 ° C. and soldering at a low temperature below 450 ° C.

As described above, according to the third embodiment, the same operational effect as that of the above-described first embodiment can be obtained.

Further, in the third embodiment, the coating 31 formed by spraying a material as a base for brazing on the upper surface of the coating 13 of the insulating material formed by thermal spraying and the external heat exchange member. The first by brazing
The thermal contact between the film 31 and the external heat exchange member, that is, the thermal contact between the film 13 of the insulating material and the external heat exchange member can be further improved as compared with the case of the embodiment. .

As in the case of the insulating material film 13,
The insulating material film 31 may be formed only on either the high temperature side or the low temperature side of the thermoelectric module.

[Fourth Embodiment] FIG. 4 is a side view showing a thermoelectric module according to a fourth embodiment of the present invention.

The thermoelectric module 40 shown in FIG.
In the configuration of the thermoelectric module 10 of the first embodiment shown in, the coating 41 is added. In the configuration of the thermoelectric module 20 of the second embodiment,
You may make it the structure which added the film 41. Note that, in FIG. 4, parts that perform the same functions as the components shown in FIG. 1 are given the same reference numerals.

The coating film 41 is formed on the upper surface of the coating film 13 formed by thermal spraying of the insulating material, that is, on the contact surface side with the external heat exchange member (not shown) on the side opposite to the thermoelectric element, and further, the insulating material, that is, the coating film 13. It is formed by thermal spraying a material for thermal stress relaxation having a larger linear expansion coefficient. In addition,
Copper (Cu), nickel (N
i), aluminum (Al), etc. are considered.

As described above, according to the fourth embodiment, the same operational effect as that of the above-described first embodiment can be obtained.

In the fourth embodiment, the linear expansion coefficient of the insulating material is relatively smaller than that of the electrode material and the like. Therefore, the insulating material warps due to the thermal expansion and thermal contraction of the electrode material, and a large thermal stress is likely to occur. However, by spraying the thermal stress relaxation material on the upper surface of the insulating film 13 generated by thermal spraying, the thermal stress generated inside the thermoelectric module due to temperature change can be suppressed, and damage due to thermal stress can be prevented in advance. The heat resistance and durability of the thermoelectric module can be improved.

By the way, in the above-mentioned third and fourth embodiments, for many thermoelectric elements Ep and En,
The adjacent thermoelectric element Ep and thermoelectric element En are electrically and mechanically connected to each other by using the electrode plate 11, but the present invention is not limited to this, and the above-described second
As in the case of the above embodiment, adjacent thermoelectric elements Ep and En may be directly and electrically connected to each other.

That is, in the third embodiment, the film 31 is formed on the insulating material film 21, and in the fourth embodiment, the film 41 is formed on the insulating material film 21. .

When the adjacent thermoelectric elements Ep and En are electrically connected directly to each other as described above, in the above-described third and fourth embodiments,
In addition to the respective operational effects, the operational effects similar to those of the above-described second embodiment are exhibited.

[Fifth Embodiment] FIG. 5 is a schematic side view showing a fifth embodiment of a thermoelectric module according to the present invention.

The thermoelectric module 50 shown in FIG.
In the configuration of the conventional thermoelectric module A shown in (1), the thermoelectric elements Ep and En further have a film 51 of an insulating material. Note that, in FIG. 5, parts having the same functions as those of the components shown in FIG. 6 are denoted by the same reference numerals.

The insulating material film 51 is formed by spraying an insulating material on the surface of the thermoelectric element which is not to be electrically connected to the electrode before the step of joining the thermoelectric element and the electrode. When the insulating material is sprayed on the thermoelectric element, a masking process or the like is performed in advance on the electrical connection portion with the electrode of the thermoelectric element to prevent the insulating material from adhering.

The insulating material film formed by thermal spraying can be formed as thin as about 0.05 mm. If a film with the minimum thickness that can form a film by thermal spraying and can withstand the voltage applied to or generated by the thermoelectric element is formed, the thermoelectric element adjacent to the thermoelectric element formed with the insulating material film will be insulated. Even if the material parts come into contact with each other, they are not electrically connected. Therefore, a plurality of thermoelectric elements can be arranged at high density in the thermoelectric module, and the thermoelectric characteristics with respect to the external dimensions can be improved. The insulating material sprayed on the thermoelectric element is preferably a material having low thermal conductivity such as zirconia ceramics so that the loss of the heat flow transmitted through the portion can be suppressed and a temperature difference can be efficiently provided in the thermoelectric element portion.

As described above, according to the fifth embodiment, it is possible to provide a thermoelectric module in which a plurality of thermoelectric elements can be arranged in high density in the thermoelectric module and which improves the thermoelectric characteristics with respect to the outer dimensions. .

In the fifth embodiment described above, the insulation between the thermoelectric element and the external heat exchange member is based on the structure of the conventional thermoelectric module, but the present invention is not limited to this. Alternatively, the configuration may be the same as that of any one of the first to fourth embodiments described above. In that case, the same effect as that of the embodiment can be obtained at the same time.

[Brief description of drawings]

FIG. 1 is a side conceptual view showing a first embodiment of a thermoelectric module according to the present invention.

FIG. 2 is a side view conceptual diagram showing a second embodiment of a thermoelectric module according to the present invention.

FIG. 3 is a side conceptual view showing a third embodiment of a thermoelectric module according to the present invention.

FIG. 4 is a side conceptual view showing a fourth embodiment of a thermoelectric module according to the present invention.

FIG. 5 is a side conceptual view showing a fifth embodiment of a thermoelectric module according to the present invention.

FIG. 6 is a side view conceptual diagram showing a conventional thermoelectric module.

[Explanation of symbols]

10, 20, 30, 40, 50, A thermoelectric module, 11, D electrode plate, 12, F solder 13,21,51 insulation film, 14, G diffusion prevention layer, 31,41 film, Ep, En thermoelectric element C Solder or brazing material B Ceramics plate

Claims (3)

[Claims] 1. A thermoelectric module comprising a plurality of thermoelectric elements electrically connected to each other, wherein at least a part of the thermoelectric elements has a film formed by thermal spraying of an insulating material. module. 2. The thermoelectric module according to claim 1, wherein a surface of the thermoelectric element facing the external heat exchange member has a film formed by thermal spraying of an insulating material. 3. The thermoelectric module according to claim 1, wherein a surface of the thermoelectric element facing the adjacent thermoelectric element has a film formed by thermal spraying of an insulating material.