JP2009081286A

JP2009081286A - Thermoelectric conversion module

Info

Publication number: JP2009081286A
Application number: JP2007249695A
Authority: JP
Inventors: Takushi Kita; 拓志木太; Kazuo Ebisumori; 一雄戎森
Original assignee: Aisin Seiki Co Ltd; Toyota Motor Corp
Current assignee: Toyota Motor Corp; Aisin Corp
Priority date: 2007-09-26
Filing date: 2007-09-26
Publication date: 2009-04-16

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermoelectric conversion module which prevents the breakage of a thermoelectric conversion element caused by a thermal stress. <P>SOLUTION: The thermoelectric conversion module 200 includes a pair of electrodes 13 and 14, and one or more thermoelectric conversion elements disposed between the pair of electrodes 13 and 14. At least one of the thermoelectric conversion elements comprises two or more thermoelectric conversion element split pieces that are not fixed to each other at an interface but are stacked in a current channel direction. The height (L) and the width (W) of the thermoelectric conversion element split piece satisfy the relation represented by expression (1), where σ<SB>TE</SB>denotes rupture strength, α denotes linear expansion coefficient, E denotes elastic modulus, T<SB>H</SB>denotes the high-temperature side temperature of the thermoelectric conversion element split piece, T<SB>R</SB>denotes the initial temperature of the thermoelectric conversion element split piece, and T<SB>C</SB>denotes the low-temperature side temperature of the thermoelectric conversion element split piece. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

本発明は、温度差による熱応力を緩和することが可能な熱電変換素子を有する熱電変換モジュールに関する。 The present invention relates to a thermoelectric conversion module having a thermoelectric conversion element capable of relieving thermal stress due to a temperature difference.

熱電変換は、熱と電気とが互いに変換される現象であり、モーターなどの動力を介在させることなく熱と電気が直に変換されることから、この現象を利用した熱電変換素子の開発は、近年省エネルギーの観点から注目を集めている。
熱電変換素子の１種である発電素子は、固体の両端に温度差を与えた際起電力が生じるゼーベック効果を利用したものであり、ごみ焼却場や発電所から生じる廃熱や地熱等の熱エネルギーから電力を直接取り出せる点で、産業全体のエネルギー利用効率を高める役割を果たしている。
また、他の熱電変換素子の１種である加熱・冷却素子は、固体の両端に電位差を与えた際温度差が生じるペルチエ効果を利用したものであり、騒音や振動を生じることなく加熱又は冷却が可能であることから、家庭用の電子機器に用いられている。 Thermoelectric conversion is a phenomenon in which heat and electricity are converted into each other, and since heat and electricity are directly converted without the power of a motor or the like, the development of thermoelectric conversion elements using this phenomenon is In recent years, it has attracted attention from the viewpoint of energy saving.
A power generation element, which is a type of thermoelectric conversion element, uses the Seebeck effect, which generates an electromotive force when a temperature difference is applied to both ends of a solid. Heat generated from waste incinerators and power plants, such as waste heat and geothermal heat It plays the role of improving the energy utilization efficiency of the entire industry in that power can be extracted directly from energy.
In addition, the heating / cooling element, which is one type of other thermoelectric conversion elements, utilizes the Peltier effect that generates a temperature difference when a potential difference is applied to both ends of a solid, and can be heated or cooled without causing noise or vibration. Therefore, it is used for household electronic devices.

熱電変換素子にはその用途から、高い導電率、大きな熱起電力、低い熱伝導率の３つを併せ持つ材料、すなわち、電気はよく通すが熱は伝えない材料を用いることが好ましい。その観点から、通常熱電変換素子には良導体と絶縁体の中間の性質を持つ半導体が用いられる。 For the thermoelectric conversion element, it is preferable to use a material having three of high conductivity, large thermoelectromotive force, and low thermal conductivity, that is, a material that conducts electricity well but does not transmit heat because of its use. From this point of view, a semiconductor having an intermediate property between a good conductor and an insulator is usually used for the thermoelectric conversion element.

実用的には、ｐ型熱電変換素子及びｎ型熱電変換素子を交互に配置し、直列に配線することによって、発電出力又は加熱・冷却出力の増大を図る。図１は一般的な熱電変換モジュールの層構成を模式的に示した図である。図１に示すように、熱電変換モジュール１００は、升目状に交互に配置されたｐ型熱電変換素子１又はｎ型熱電変換素子２を、一対の電極３によって挟持し、さらに当該挟持物を電極３の両側から基板４で挟持したものから成る。この時前記電極３をそれぞれ対応する熱電変換素子に接合することで、全ての熱電変換素子が電気的に直列に配線され、端の電極５から導線を引き電源又は電源を必要とする機器に接続することができる。
発電装置として用いる場合は、２枚の前記基板４に温度差をかけることにより、各素子に起電力が生じ、電流が流れる。加熱・冷却装置として用いる場合は、２枚の端の電極５に電位差を与えることにより、各素子の両端で温度差が生じ、その結果２枚の基板４の温度差に作用し、加熱又は冷却が可能になる。
前記端の電極５を延長し、他の熱電変換モジュールと接続することで、発電出力又は加熱若しくは冷却出力を増加させることもできる。 Practically, p-type thermoelectric conversion elements and n-type thermoelectric conversion elements are alternately arranged and wired in series to increase the power generation output or heating / cooling output. FIG. 1 is a diagram schematically showing a layer structure of a general thermoelectric conversion module. As shown in FIG. 1, the thermoelectric conversion module 100 sandwiches p-type thermoelectric conversion elements 1 or n-type thermoelectric conversion elements 2 that are alternately arranged in a grid shape by a pair of electrodes 3, and further the sandwiched objects are electroded. 3 is sandwiched between the substrates 4 from both sides. At this time, by joining the electrodes 3 to the corresponding thermoelectric conversion elements, all the thermoelectric conversion elements are electrically wired in series, and a lead wire is drawn from the electrode 5 at the end and connected to a device that requires a power source or a power source. can do.
When used as a power generation device, an electromotive force is generated in each element by applying a temperature difference between the two substrates 4, and a current flows. When used as a heating / cooling device, a temperature difference is generated at both ends of each element by applying a potential difference to the electrodes 5 at the two ends. As a result, the temperature difference between the two substrates 4 acts on the heating or cooling. Is possible.
The power generation output or heating or cooling output can be increased by extending the electrode 5 at the end and connecting it to another thermoelectric conversion module.

発電素子として各素子にかける温度差は、通常５０〜８００℃、及び加熱・冷却素子として各素子にかかる温度差は、通常２０〜８０℃にも達する。かかる温度差による熱伸縮から生じる熱電変換素子の破壊は致命的な問題である。この問題を解決するために、例えば、特許文献１においては、熱電変換素子を複数部分（より具体的には、高温側と低温側の２つ）に分割し、その合わせ面がスライドすることを可能にすることにより、温度差による熱伸縮差を吸収させる構造を提案している。 The temperature difference applied to each element as a power generating element is usually 50 to 800 ° C., and the temperature difference applied to each element as a heating / cooling element usually reaches 20 to 80 ° C. The destruction of the thermoelectric conversion element resulting from thermal expansion and contraction due to such a temperature difference is a fatal problem. In order to solve this problem, for example, in Patent Document 1, the thermoelectric conversion element is divided into a plurality of parts (more specifically, two on the high temperature side and the low temperature side), and the mating surface slides. By making it possible, the structure which absorbs the thermal expansion-contraction difference by a temperature difference is proposed.

実開平３−１１２９５５号公報Japanese Utility Model Publication No. 3-112955

しかし、特許文献１においては、熱電変換素子に付与される温度差による熱応力は分割によって緩和されるが、熱電変換素子を分割した個々の熱電変換素子分割片自体に付与される温度差による熱応力は考慮されていない。したがって、熱電変換素子全体としては熱伸縮差を吸収させることができたとしても、個々の熱電変換素子分割片が熱応力によって破壊され、その結果熱電変換素子として機能できなくなるということがあり得る。 However, in Patent Document 1, the thermal stress due to the temperature difference applied to the thermoelectric conversion element is alleviated by the division, but the heat due to the temperature difference applied to the individual thermoelectric conversion element divided pieces itself obtained by dividing the thermoelectric conversion element. Stress is not considered. Therefore, even if the thermoelectric conversion element as a whole can absorb the thermal expansion / contraction difference, the individual thermoelectric conversion element divided pieces may be destroyed by thermal stress, and as a result, the thermoelectric conversion element cannot function.

上記のように、熱電変換素子の熱応力による破壊を防ぐには、熱電変換素子自体の設計に更なる改善が必要であった。本発明は、熱電変換素子分割片の寸法を規定することによって、個々の熱電変換素子自体に付与される温度差による熱応力の緩和を図ることを目的とする。 As described above, in order to prevent destruction of the thermoelectric conversion element due to thermal stress, further improvements have been required in the design of the thermoelectric conversion element itself. An object of the present invention is to alleviate thermal stress due to a temperature difference applied to each thermoelectric conversion element itself by defining the dimensions of the thermoelectric conversion element divided pieces.

本発明の熱電変換モジュールは、一対の電極と、該一対の電極間に設けられた熱電変換素子を具備し、少なくとも１つの前記熱電変換素子が、２片以上の熱電変換素子分割片同士が界面において固着せずに電流流路方向に積み重なることで構成されており、且つ、前記熱電変換素子分割片の高さ（Ｌ）と当該熱電変換素子分割片の幅（Ｗ）とが、下記式（１）の関係を満たすことを特徴とする。 The thermoelectric conversion module of the present invention comprises a pair of electrodes and a thermoelectric conversion element provided between the pair of electrodes, and at least one of the thermoelectric conversion elements is an interface between two or more pieces of thermoelectric conversion elements. And the height (L) of the thermoelectric conversion element divided pieces and the width (W) of the thermoelectric conversion element divided pieces are expressed by the following formula ( The relationship 1) is satisfied.

（ただし、上記式（１）中、σ_ＴＥは破壊強度、αは線膨張係数、Ｅは弾性率、Ｔ_Ｈは前記熱電変換素子分割片の高温側温度、Ｔ_Ｒは前記熱電変換素子分割片の初期温度、Ｔ_Ｃは前記熱電変換素子分割片の低温側温度を示す。） (However, in the above formula (1), sigma _TE is breaking strength, alpha linear expansion coefficient, E is the elastic modulus, T _H is a high temperature-side temperature of the thermoelectric conversion elements divided pieces, T _R is the thermoelectric conversion elements divided piece initial temperature of, T _C denotes a lower side temperature of the thermoelectric conversion elements divided pieces.)

このような構成の熱電変換モジュールは、熱電変換素子の寸法を上記式（１）のように規定することによって、個々の熱電変換素子分割片自体に付与される温度差による熱応力を緩和することができ、それにより熱電変換素子自体の破壊を防止することができる。 The thermoelectric conversion module having such a configuration alleviates thermal stress due to a temperature difference applied to each segment of the thermoelectric conversion element itself by defining the dimensions of the thermoelectric conversion element as in the above formula (1). Thereby, destruction of the thermoelectric conversion element itself can be prevented.

本発明の熱電変換モジュールは、同じ前記熱電変換素子に含まれる前記熱電変換素子分割片のうち、少なくとも１つの当該熱電変換素子分割片の前記幅（Ｗ）が、他の前記熱電変換素子分割片の前記幅（Ｗ）よりも小さいことが好ましい。 In the thermoelectric conversion module of the present invention, among the thermoelectric conversion element divided pieces included in the same thermoelectric conversion element, the width (W) of at least one of the thermoelectric conversion element divided pieces is the other thermoelectric conversion element divided piece. Is preferably smaller than the width (W).

このような構成の熱電変換モジュールは、前記熱電変換素子分割片の前記幅（Ｗ）を小さくするのに伴って、上記式（１）より前記熱電変換素子分割片の前記高さ（Ｌ）を小さくすることができ、その結果熱電変換モジュール全体の高さを低くすることができるので、個々の前記熱電変換素子分割片自体に付与される温度差による熱応力を緩和しながら熱電変換モジュールの占有体積を小さくすることができる。 In the thermoelectric conversion module having such a configuration, as the width (W) of the thermoelectric conversion element segment is reduced, the height (L) of the thermoelectric conversion element segment is calculated from the above formula (1). As a result, the overall height of the thermoelectric conversion module can be reduced, so that the thermoelectric conversion module occupies while relaxing the thermal stress due to the temperature difference applied to each of the thermoelectric conversion element segment pieces itself. The volume can be reduced.

本発明によれば、熱電変換素子の寸法を上記式（１）のように規定することによって、個々の熱電変換素子分割片自体に付与される温度差による熱応力を緩和することができ、熱電変換素子自体の破壊を防止することができる。 According to the present invention, by defining the dimensions of the thermoelectric conversion elements as in the above formula (1), the thermal stress due to the temperature difference applied to each thermoelectric conversion element segment itself can be alleviated, and the thermoelectric conversion element is reduced. The destruction of the conversion element itself can be prevented.

本発明の熱電変換モジュールは、一対の電極と、該一対の電極間に設けられた熱電変換素子を具備し、少なくとも１つの前記熱電変換素子が、２片以上の熱電変換素子分割片同士が界面において固着せずに電流流路方向に積み重なることで構成されており、且つ、前記熱電変換素子分割片の高さ（Ｌ）と当該熱電変換素子分割片の幅（Ｗ）とが、下記式（１）の関係を満たすことを特徴とする。 The thermoelectric conversion module of the present invention includes a pair of electrodes and a thermoelectric conversion element provided between the pair of electrodes, and at least one of the thermoelectric conversion elements is an interface between two or more pieces of thermoelectric conversion element segments. And the height (L) of the thermoelectric conversion element divided pieces and the width (W) of the thermoelectric conversion element divided pieces are expressed by the following formula ( The relationship 1) is satisfied.

ここでいう「高さ」とは、電流流路方向に略平行方向の長さのことをいう。また、ここでいう「幅」とは、電流流路方向に略垂直方向の長さのことをいう。 Here, “height” refers to a length in a direction substantially parallel to the current flow path direction. Further, the “width” here means a length in a direction substantially perpendicular to the current flow path direction.

ここでいう「初期温度」とは、前記熱電変換素子を発電素子として用いる場合には温度差を付与する前の素子の温度のことを、前記熱電変換素子を加熱・冷却素子として用いる場合には素子の両端に電圧を付与することで温度差が生じる前の素子の温度のことを、それぞれ示す。 “Initial temperature” as used herein refers to the temperature of the element before providing a temperature difference when the thermoelectric conversion element is used as a power generation element, and when the thermoelectric conversion element is used as a heating / cooling element. The temperature of the element before the temperature difference is generated by applying a voltage to both ends of the element is shown.

また、上記「前記熱電変換素子分割片の高さ（Ｌ）と当該熱電変換素子分割片の幅（Ｗ）とが、下記式（１）の関係を満たす」とは、多分割片を積み重ねた熱電変換素子全体の高さ及び幅に関しては、上記式（１）の関係を満たさず、多分割片を積み重ねた熱電変換素子を構成する全ての熱電変換素子分割片の高さ及び幅が、個々に上記式（１）の関係を満たすということである。 In addition, the above-mentioned “the height (L) of the thermoelectric conversion element divided pieces and the width (W) of the thermoelectric conversion element divided pieces satisfy the relationship of the following formula (1)” means that the multi-divided pieces are stacked. Regarding the height and width of the whole thermoelectric conversion element, the height and width of all the thermoelectric conversion element divided pieces constituting the thermoelectric conversion element in which the multi-division pieces are stacked without satisfying the relationship of the above formula (1) are individually In other words, the relationship of the above formula (1) is satisfied.

前記熱電変換素子は、実用的にはｐ型熱電変換素子及びｎ型熱電変換素子を交互に並べて用いる。 As the thermoelectric conversion element, a p-type thermoelectric conversion element and an n-type thermoelectric conversion element are practically used alternately.

ここでいうｐ型熱電変換素子とは、ペルチエ効果を利用した加熱・冷却素子においては、当該素子に流れる電流の上流で冷却され、電流の下流で加熱されるものをいう。また、ゼーベック効果を利用した発電素子においては、当該素子の冷却された低温側から加熱された高温側に向かって電流が流れるものをいう。
具体的には、テルル化ビスマス（Ｂｉ_２Ｔｅ_３）とテルル化アンチモン（Ｓｂ_２Ｔｅ_３）との固溶体に代表されるビスマステルル系材料、ＰｂＴｅに代表される鉛テルル系材料、コバルト酸化物に代表される金属酸化物系材料、Ｓｉ_０．８Ｇｅ_０．２に代表されるシリコンゲルマニウム系材料、コバルトとアンチモンの合金を含むスクッテルダイド化合物系材料、金属ケイ化物であるシリサイド化合物系材料、Ｂａ_８Ｇａ_１８−ｘＧｅ_２８＋ｘ（０≦ｘ≦２）に代表されるクラスレート化合物系材料が挙げられる。この内、鉛やテルル、アンチモン等の毒性の高い金属を含まず、且つ、コバルトのような高価な希少金属を含まないという点で、クラスレート化合物系材料を用いるのが好ましい。 The p-type thermoelectric conversion element here refers to a heating / cooling element using the Peltier effect that is cooled upstream of the current flowing through the element and heated downstream of the current. Moreover, in the electric power generation element using the Seebeck effect, it means that a current flows from the cooled low temperature side of the element toward the heated high temperature side.
Specifically, a bismuth tellurium-based material typified by a solid solution of bismuth telluride (Bi ₂ Te ₃ ) and antimony telluride (Sb ₂ Te ₃ ), a lead tellurium-based material typified by PbTe, a cobalt oxide Representative metal oxide materials, silicon germanium materials typified by Si _0.8 Ge _0.2 , skutterudide compound materials including alloys of cobalt and antimony, silicide compound materials that are metal silicides, Ba ₈ A clathrate compound-based material represented by Ga _18-x Ge _{28 + x} (0 ≦ x ≦ 2) can be given. Of these, the clathrate compound-based material is preferably used in that it does not contain a highly toxic metal such as lead, tellurium, and antimony and does not contain an expensive rare metal such as cobalt.

ここでいうｎ型熱電変換素子とは、ペルチエ効果を利用した加熱・冷却素子においては、当該素子に流れる電流の上流で加熱され、電流の下流で冷却されるものをいう。また、ゼーベック効果を利用した発電素子においては、当該素子の加熱された高温側から冷却された低温側に向かって電流が流れるものをいう。
具体的には、テルル化ビスマス（Ｂｉ_２Ｔｅ_３）とセレン化ビスマス（Ｂｉ_２Ｓｅ_３）との固溶体に代表されるビスマステルル系材料、ＰｂＴｅに代表される鉛テルル系材料、コバルト酸化物に代表される金属酸化物系材料、Ｓｉ_０．８Ｇｅ_０．２に代表されるシリコンゲルマニウム系材料、コバルトとアンチモンの合金を含むスクッテルダイド化合物系材料、金属ケイ化物であるシリサイド化合物系材料、Ｂａ_８Ｇａ_１８−ｘＧｅ_２８＋ｘ（２≦ｘ≦４）に代表されるクラスレート化合物系材料が挙げられる。この内、鉛やテルル、アンチモン等の毒性の高い金属を含まず、且つ、コバルトのような高価な希少金属を含まないという点で、クラスレート化合物系材料を用いるのが好ましい。 The n-type thermoelectric conversion element here refers to a heating / cooling element using the Peltier effect that is heated upstream of the current flowing through the element and cooled downstream of the current. Moreover, in the electric power generation element using the Seebeck effect, the current flows from the heated high temperature side of the element toward the cooled low temperature side.
Specifically, a bismuth tellurium-based material typified by a solid solution of bismuth telluride (Bi ₂ Te ₃ ) and bismuth selenide (Bi ₂ Se ₃ ), a lead tellurium-based material typified by PbTe, a cobalt oxide Representative metal oxide materials, silicon germanium materials typified by Si _0.8 Ge _0.2 , skutterudide compound materials including alloys of cobalt and antimony, silicide compound materials that are metal silicides, Ba ₈ A clathrate compound-based material represented by Ga _18-x Ge _{28 + x} (2 ≦ x ≦ 4) can be given. Of these, the clathrate compound-based material is preferably used in that it does not contain a highly toxic metal such as lead, tellurium, and antimony and does not contain an expensive rare metal such as cobalt.

ここでいう電極とは、熱電変換素子を直列に配列することで熱電変換素子間の電子の授受を補助するものである。なお、後述のように基板と熱電変換素子との熱のやり取りを妨げてはならないことから、熱抵抗が小さく良導体であることが要求され、銅、アルミニウム、ニッケル、金、タングステン等またこれらの合金を用いることができる。この中では、特に良導体として優れている銅を用いるのが好ましい。
また、熱電変換素子と拡散接合ができるように、電極内にチタンを混合したチタン‐銅電極を用いることもできる。 An electrode here is what assists transfer of the electron between thermoelectric conversion elements by arranging a thermoelectric conversion element in series. As will be described later, since heat exchange between the substrate and the thermoelectric conversion element must not be hindered, it is required to have a low thermal resistance and a good conductor, such as copper, aluminum, nickel, gold, tungsten, and alloys thereof. Can be used. Among these, it is preferable to use copper which is particularly excellent as a good conductor.
In addition, a titanium-copper electrode in which titanium is mixed in the electrode can be used so that diffusion bonding with the thermoelectric conversion element can be performed.

ここでいう基板とは、電極を通じて熱電変換素子と熱の授受を行うものである。熱抵抗が小さく絶縁体であること、耐振動及び衝撃性に優れること等が要求されることから、材質としてはアルミナ、ムライト、シリコンカーバイド、アルミナイトライド、シリコンナイトライドのうち少なくとも１種からなる焼結体を例示できる。特に、アルミナイトライド又はアルミナから成るセラミクスを用いるのが好ましい。
また、メタライズ電極付き基板を用いることで、はんだ付けによって素子と基板とを直接接合することができる。メタライズ電極付き基板とは、予め基板の所定の位置にメタライズ電極が薄く塗布されたものである。メタライズ電極の厚さ及び素材は、導電性とはんだ付けによる接合性とを鑑みて、５〜１００μｍの銅電極であるのが好ましい。 The substrate here refers to a substrate that transfers heat to and from the thermoelectric conversion element through electrodes. Since it is required to have a small thermal resistance, an insulator, and excellent vibration resistance and impact resistance, the material is at least one of alumina, mullite, silicon carbide, aluminum nitride, and silicon nitride. A sintered body can be exemplified. In particular, it is preferable to use ceramics made of aluminum nitride or alumina.
Further, by using the substrate with metallized electrodes, the element and the substrate can be directly joined by soldering. A substrate with a metallized electrode is one in which a metallized electrode is thinly applied to a predetermined position of the substrate in advance. The thickness and material of the metallized electrode is preferably a copper electrode of 5 to 100 μm in view of conductivity and solderability.

上記「２片以上の熱電変換素子分割片同士が界面において固着せずに電流流路方向に積み重なることで構成されており」とは、必ずしも前記分割片同士の界面が、電流流路方向に全て垂直であるということを意味しない。図２は、２片の熱電変換素子分割片と電流流路方向とを示した断面模式図である。図２（ａ）及び（ｂ）には、電流流路方向６と、電流流路方向上流の熱電変換素子分割片７及び電流流路方向下流の熱電変換素子分割片８を示している。図２（ａ）に示すように、前記分割片７及び前記分割片８の界面が、前記方向６に垂直であってもよいし、また、図２（ｂ）に示すように、前記界面が前記方向６に垂直でなく、斜めになっていてもよい。ただし、本発明から外れる例を示す図８に示すように、２つの熱電変換素子分割片９の界面が、電流流路方向６と平行であることはないものとする。
さらに、熱電変換素子分割片同士は接合されず、互いに押し付け合うことによって電気的な導通を取る。なおこの際、熱電変換素子分割片同士の界面にはすべりやすく電気的導通を妨げない材料、例えばグラファイト、金、銅を塗布することで、熱電変換素子分割片にかかる熱応力をより緩和することができる。 The above “constituted by stacking two or more pieces of thermoelectric conversion element pieces in the direction of the current flow path without sticking at the interface” means that the interface between the divided pieces is not necessarily in the direction of the current flow path. It does not mean that it is vertical. FIG. 2 is a schematic cross-sectional view showing two pieces of thermoelectric conversion element division pieces and a current flow path direction. 2A and 2B show a current flow path direction 6, a thermoelectric conversion element segment piece 7 upstream of the current flow path direction, and a thermoelectric conversion element segment piece 8 downstream of the current flow path direction. As shown in FIG. 2 (a), the interface between the divided piece 7 and the divided piece 8 may be perpendicular to the direction 6, and as shown in FIG. Instead of being perpendicular to the direction 6, it may be slanted. However, as shown in FIG. 8 showing an example outside the present invention, the interface between the two thermoelectric conversion element segment pieces 9 is not parallel to the current flow path direction 6.
Further, the thermoelectric conversion element divided pieces are not joined to each other, and are brought into electrical conduction by being pressed against each other. At this time, the thermal stress applied to the thermoelectric conversion element divided pieces can be further alleviated by applying a material that does not interfere with electrical conduction, such as graphite, gold, and copper, at the interface between the thermoelectric conversion element divided pieces. Can do.

以下、図面を参照しながら本発明について詳しく説明する。図３は本発明の熱電変換モジュールの典型例の断面模式図である。本発明の熱電変換モジュール２００は、ｐ型熱電変換素子１５及びｎ型熱電変換素子１６と、前記素子１５又は前記素子１６を挟持し且つ接合した一対の電極１３及び１４と、当該電極１３及び１４を挟持し且つ接合した一対の基板１１及び１２を有する。さらに、前記素子１５及び前記素子１６は、それぞれｐ型熱電変換素子分割片１５ａ及び１５ｂ、ｎ型熱電変換素子分割片１６ａ及び１６ｂの２片ずつが固着せずに電流流路方向に積み重なることで構成されている。
前記電極１４を延長することにより他の熱電変換素子を追加して配線することも可能で、その場合には、前記電極１４、前記ｐ型熱電変換素子１５、前記電極１３、前記ｎ型熱電変換素子１６、前記電極１４の順の繰り返し単位によって前記ｐ型熱電変換素子１５及び前記ｎ型熱電変換素子１６が交互且つ直列に配線されるようにする。 Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 3 is a schematic cross-sectional view of a typical example of the thermoelectric conversion module of the present invention. The thermoelectric conversion module 200 of the present invention includes a p-type thermoelectric conversion element 15 and an n-type thermoelectric conversion element 16, a pair of electrodes 13 and 14 sandwiching and joining the element 15 or the element 16, and the electrodes 13 and 14 A pair of substrates 11 and 12 are sandwiched and joined. Further, the element 15 and the element 16 are stacked in the direction of the current flow path without the two pieces of the p-type thermoelectric conversion element divided pieces 15a and 15b and the n-type thermoelectric conversion element divided pieces 16a and 16b being fixed to each other. It is configured.
It is also possible to add another thermoelectric conversion element by extending the electrode 14, and in this case, the electrode 14, the p-type thermoelectric conversion element 15, the electrode 13, the n-type thermoelectric conversion The p-type thermoelectric conversion element 15 and the n-type thermoelectric conversion element 16 are arranged alternately and in series by the repeating unit in the order of the element 16 and the electrode 14.

さらに、前記ｐ型熱電変換素子分割片１５ａ及び１５ｂ並びに前記ｎ型熱電変換素子分割片１６ａ及び１６ｂは、図に示すような高さＬ_１〜Ｌ_４、及び幅Ｗ_１〜Ｗ_２をそれぞれ有している。なお、Ｌ_１＋Ｌ_２＝Ｌ_３＋Ｌ_４であり、また、Ｗ_１、Ｗ_２の値は互いに独立である。
図３に示す各前記分割片の各長さの組（Ｌ_１，Ｗ_１）、（Ｌ_２，Ｗ_１）、（Ｌ_３，Ｗ_２）、（Ｌ_４，Ｗ_２）は、それぞれ上記式（１）に示す高さ方向の長さ（Ｌ）と幅方向の長さ（Ｗ）の関係を満たす。 Further, the p-type thermoelectric conversion element divided pieces 15a and 15b and the n-type thermoelectric conversion element divided pieces 16a and 16b have heights L _{1 to} L ₄ and widths W _{1 to} W ₂ as shown in the figure, respectively. is doing. Note that L ₁ + L ₂ = L ₃ + L ₄ , and the values of W ₁ and W ₂ are independent of each other.
Each set of lengths (L ₁ , W ₁ ), (L ₂ , W ₁ ), (L ₃ , W ₂ ), (L ₄ , W ₂ ) shown in FIG. The relationship between the length (L) in the height direction and the length (W) in the width direction shown in (1) is satisfied.

式（１）は、「熱電変換システム設計のための解析」（小川吉彦著、森北出版、１９９８年発行）ｐ．１０３〜１０４の記載を参考に導き出すことができる。図４は、温度差による方形構造物の変形についての説明図である。
図４に示すように、高さＬ、幅Ｗの方形の構造物２１（奥行きは省略）が始めに一様温度Ｔ_Ｒであったとする。次に、前記構造物２１の上部が温度Ｔ_Ｃに冷却され、且つ、前記構造物２１の下部が温度Ｔ_Ｈに加熱されることで、変形した構造物２２になったとする。このとき、変化した面は半径Ｒ_Ｈの円断面の一部となるが、その中心でなす角度θは十分小さいとする。 Equation (1) is “Analysis for Thermoelectric Conversion System Design” (by Yoshihiko Ogawa, Morikita Publishing, 1998) p. The description of 103-104 can be derived with reference. FIG. 4 is an explanatory view of the deformation of the rectangular structure due to the temperature difference.
As shown in FIG. 4, the height L, a structure 21 of the rectangular width W (depth shown) is assumed to be uniform temperature T _R at the beginning. Next, an upper portion of the structure 21 is cooled to a temperature T _C, and the lower part of the structure 21 by being heated to a temperature T _H, and became a structure 22 that is deformed. At this time, the changed surface becomes a part of a circular cross section having the radius _RH , but the angle θ formed at the center is sufficiently small.

図４に示す、温度Ｔ_Ｈに加熱された面（以下、高温側面と呼ぶ）の加熱後の幅Ｗ_Ｈと幅変化δＷ_Ｈは、
Ｗ_Ｈ＝Ｗ＋ δＷ_Ｈ・・・式（２）
と表される。また、温度変化に対応して長さが変化する割合を示す線膨張係数αを用いると、幅変化δＷ_Ｈ、幅Ｗ、温度Ｔ_Ｈ及び初期温度Ｔ_Ｒの関係は、式（３）のように記述できる。
δＷ_Ｈ＝ αＷ（Ｔ_Ｈ−Ｔ_Ｒ）・・・式（３） 4, the heated surface (hereinafter, hot side hereinafter) to a temperature T _H width W _H and width change .delta.W _H after heating is
W _H = W + δW _H Formula (2)
It is expressed. Moreover, the use of linear expansion coefficient indicating a rate of change in length in response to temperature change alpha, the relationship between the width variation .delta.W _H, width W, the temperature T _H and the initial temperature T _R, the equation (3) Can be described in
_{_{_{δW H = αW (T H -T}}} R) ··· (3)

図４に示す、温度Ｔ_Ｃに冷却された面（以下、低温側面と呼ぶ）の冷却後の幅Ｗ_Ｃと幅変化δＷ_Ｃは、
Ｗ_Ｃ＝Ｗ − δＷ_Ｃ・・・式（４）
と表される。また、温度変化に対応して長さが変化する割合を示す線膨張係数αを用いると、幅変化δＷ_Ｃ、幅Ｗ、温度Ｔ_Ｃ及び初期温度Ｔ_Ｒの関係は、式（５）のように記述できる。
δＷ_Ｃ＝ αＷ（Ｔ_Ｒ−Ｔ_Ｃ）・・・式（５） 4, a surface that is cooled to a temperature T _C (hereinafter, low-temperature side is referred to as) the width W _C and width change .delta.W _C after cooling of,
W _C = W−δW _C Formula (4)
It is expressed. Moreover, the use of the linear expansion coefficient α indicating the ratio of length to correspond to the temperature change varies, the relationship between the width variation .delta.W _C, the width W, the temperature T _C and the initial temperature T _R, the equation (5) Can be described in
δW _C = αW (T _R −T _C ) (5)

さらに、角度θは十分小さいとの仮定より、以下に示す式（６）が成立する。式（６）の式変形により式（７）が得られる。 Furthermore, from the assumption that the angle θ is sufficiently small, the following equation (6) is established. Expression (7) is obtained by the expression modification of Expression (6).

式（２）乃至（５）及び式（７）を用いることで、図４に示す高さ変化ΔＬ_Ｈは、式（８）のように表すことができる。 By using Expressions (2) to (5) and Expression (7), the height change ΔL _H shown in FIG. 4 can be expressed as Expression (8).

また、弾性率Ｅを用いると、高さ変化ΔＬ_Ｈ、高さＬ、破壊強度σの関係は、式（９）のように記述できる。
σ ＝Ｅ（ΔＬ_Ｈ／Ｌ）・・・式（９）
したがって、式（９）に式（８）を代入して、以下に示す式（１０）を得る。 When the elastic modulus E is used, the relationship between the height change ΔL _H , the height L, and the fracture strength σ can be described as in Expression (9).
σ = E (ΔL _H / L) (9)
Therefore, the following formula (10) is obtained by substituting the formula (8) into the formula (9).

一方、前記構造物２１及び２２を、熱変形前後の熱電変換素子分割片と見立てた際に、熱電変換素子分割片の破壊強度をσ_ＴＥとすると、熱電変換素子分割片が自身の熱応力で破壊されないためには「σ＜σ_ＴＥ」でなければならない。したがって式（１０）を用いることにより、以下に示す通り式（１）が求められた。 On the other hand, when the structures 21 and 22 are regarded as thermoelectric conversion element divided pieces before and after thermal deformation, assuming that the fracture strength of the thermoelectric conversion element divided pieces is σ _TE , the thermoelectric conversion element divided pieces are caused by their own thermal stress. In order not to be destroyed, “σ <σ _TE ” must be satisfied. Therefore, by using equation (10), equation (1) was obtained as shown below.

なお、破壊強度σ_ＴＥは、４点曲げ試験により求めることができる。線膨張係数αは、ＴＭＡ８１４０（理学電気（株））を用いて、ＴＭＡ法により求めることができる。弾性率Ｅは、パルス法により求めることができる。前記熱電変換素子分割片の高温側温度Ｔ_Ｈと初期温度Ｔ_Ｒの温度差（Ｔ_Ｈ−Ｔ_Ｒ）、及び高温側温度Ｔ_Ｈと低温側温度Ｔ_Ｃの温度差（Ｔ_Ｈ−Ｔ_Ｃ）は、熱電対による直接計測により求めることができる。 The fracture strength σ _TE can be obtained by a four-point bending test. The linear expansion coefficient α can be obtained by the TMA method using TMA8140 (Rigaku Corporation). The elastic modulus E can be obtained by a pulse method. The temperature difference between the upper temperature _{T H} and the initial temperature _{T R} of the thermoelectric conversion elements divided pieces _(T H _-T R), and the high temperature-side temperature _{T H} and the temperature difference between the cold side temperature _{T C _(T} H _-T _C) Can be obtained by direct measurement with a thermocouple.

また、図３においては前記ｐ型熱電変換素子１５及び前記ｎ型熱電変換素子１６のいずれも２つの熱電変換素子分割片が積み重なることで構成されているが、前記素子１５及び前記素子１６のいずれか１つが、熱電変換素子分割片が積み重なることで構成されていてもよい。また、３つ以上の熱電変換素子分割片が積み重なることで構成されていてもよいし、さらには、前記素子１５及び前記素子１６とで積み重なる熱電変換素子分割片の数が異なっていてもよい。なお、一般的な設計においては、すべての前記素子１５及び前記素子１６の高さ（すなわち、すべての前記素子１５又は前記素子１６を構成する熱電変換素子分割片の高さの和）を等しくする必要がある。仮に１つの素子の高さが他の素子の高さと異なるとすると、基板によるすべての素子の挟持を正しく行うことができなくなってしまい、基板と各素子との熱の授受が不完全になり、その結果発電出力又は加熱若しくは冷却出力の極端な減少を招いてしまうことになる。 In FIG. 3, each of the p-type thermoelectric conversion element 15 and the n-type thermoelectric conversion element 16 is configured by stacking two thermoelectric conversion element divided pieces. One of them may be configured by stacking thermoelectric conversion element division pieces. Moreover, you may be comprised by stacking three or more thermoelectric conversion element division | segmentation pieces, Furthermore, the number of the thermoelectric conversion element division | segmentation pieces stacked by the said element 15 and the said element 16 may differ. In a general design, the heights of all the elements 15 and 16 (that is, the sum of the heights of the thermoelectric conversion element divided pieces constituting all the elements 15 or 16) are made equal. There is a need. If the height of one element is different from the height of the other elements, it becomes impossible to correctly hold all the elements by the substrate, and heat transfer between the substrate and each element becomes incomplete, As a result, the power generation output or the heating or cooling output is drastically reduced.

さらに、図５に示すように、熱電変換素子分割片同士の界面が電流流路方向に斜めになっている場合は、最も短い高さＬに関してのみ考慮すればよい。この理由としては、上記式（１）を考慮すると、式（１）中のＬが最も小さい時において、式（１）の条件が最も厳しくなるからであり、Ｌの最小値が式（１）を満たせば、熱電変換素子分割片中のいかなる高さＬも式（１）を満たすからである。したがって、図５においては、熱電変換素子分割片１５ａ、１５ｂ、１６ａ及び１６ｂに関する各長さの組（Ｌ_７，Ｗ_３）、（Ｌ_６，Ｗ_３）、（Ｌ_９，Ｗ_４）、（Ｌ_１２，Ｗ_４）が、それぞれ上記式（１）に示す高さ（Ｌ）と幅（Ｗ）の関係を満たしていればよく、高さＬ_５、Ｌ_８、Ｌ_１０、Ｌ_１１に関しては考慮しなくてよい。 Furthermore, as shown in FIG. 5, when the interface between the thermoelectric conversion element divided pieces is slanted in the direction of the current flow path, only the shortest height L needs to be considered. The reason for this is that when the above formula (1) is taken into consideration, the condition of the formula (1) becomes most severe when L in the formula (1) is the smallest, and the minimum value of L is the formula (1). This is because any height L in the thermoelectric conversion element segment satisfies the formula (1). Therefore, in FIG. 5, the sets of lengths (L ₇ , W ₃ ), (L ₆ , W ₃ ), (L ₉ , W ₄ ), (L) for the thermoelectric conversion element segment pieces 15 a, 15 b, 16 a and 16 b ( L ₁₂ , W ₄ ) need only satisfy the relationship between the height (L) and the width (W) shown in the above formula (1), and the heights L ₅ , L ₈ , L ₁₀ , and L ₁₁ There is no need to consider.

図６は本発明の熱電変換モジュールの変形例の断面模式図である。本発明の熱電変換モジュール３００は、ｐ型熱電変換素子３５及びｎ型熱電変換素子３６と、前記素子３５又は前記素子３６を挟持し且つ接合した一対の電極３３及び３４と、当該電極３３及び３４を挟持し且つ接合した一対の基板３１及び３２を有する。さらに、前記素子３６は、ｎ型熱電変換素子分割片３６ａ及び３６ｂの２片が固着せずに電流流路方向に積み重なることで構成されている。
前記電極３４を延長することにより他の熱電変換素子を追加して配線することも可能で、その場合には、前記電極３４、前記ｐ型熱電変換素子３５、前記電極３３、前記ｎ型熱電変換素子３６、前記電極３４の順の繰り返し単位によって前記ｐ型熱電変換素子３５及び前記ｎ型熱電変換素子３６が交互且つ直列に配線されるようにする。 FIG. 6 is a schematic cross-sectional view of a modification of the thermoelectric conversion module of the present invention. The thermoelectric conversion module 300 of the present invention includes a p-type thermoelectric conversion element 35 and an n-type thermoelectric conversion element 36, a pair of electrodes 33 and 34 that sandwich and join the element 35 or the element 36, and the electrodes 33 and 34. A pair of substrates 31 and 32 are sandwiched and joined. Furthermore, the element 36 is configured by stacking the n-type thermoelectric conversion element split pieces 36a and 36b in the direction of the current flow path without being fixed.
It is possible to add another thermoelectric conversion element by extending the electrode 34, and in this case, the electrode 34, the p-type thermoelectric conversion element 35, the electrode 33, the n-type thermoelectric conversion. The p-type thermoelectric conversion element 35 and the n-type thermoelectric conversion element 36 are arranged alternately and in series by the repeating unit in the order of the element 36 and the electrode 34.

さらに、前記ｐ型熱電変換素子３５並びに前記ｎ型熱電変換素子分割片３６ａ及び３６ｂは、図に示すような高さＬ_１３〜Ｌ_１５、幅Ｗ_５〜Ｗ_７をそれぞれ有しており、Ｗ_６＞Ｗ_７である。なお、Ｌ_１３＝Ｌ_１４＋Ｌ_１５である。
さらに、図６に示す各前記分割片の各長さの組（Ｌ_１３，Ｗ_５）、（Ｌ_１４，Ｗ_６）、（Ｌ_１５，Ｗ_７）は、それぞれ上記式（１）に示す高さ（Ｌ）と幅（Ｗ）の関係を満たす。 Further, the p-type thermoelectric conversion element 35 and the n-type thermoelectric conversion elements divided pieces 36a and 36b has a height _L 13 _{~L 15} as shown in FIG, the width _W 5 to _W-7, respectively, W _6> is a _{W 7.} Note that L ₁₃ = L ₁₄ + L ₁₅ .
Furthermore, each length set (L ₁₃ , W ₅ ), (L ₁₄ , W ₆ ), (L ₁₅ , W ₇ ) of each of the divided pieces shown in FIG. Satisfies the relationship between length (L) and width (W).

上記式（１）によって寸法を規定され、且つ、２片以上の幅（Ｗ）が等しい熱電素子分割片から構成されている熱電変換素子を用いる際、高さ（Ｌ）と幅（Ｗ）の関係が既に上記式（１）によって規定されていることから、自由に高さ（Ｌ）を変更することは難しい。しかし、図６に示すように、同じ前記素子３６に含まれる前記分割片３６ｂの前記幅Ｗ_７が、他の前記分割片３６ａの前記幅Ｗ_６よりも小さいという構成を採用することにより、前記幅Ｗ_７を小さくするのに伴って、上記式（１）より前記分割片３６ｂの前記高さＬ_１５を小さく抑えることができ、前記素子３６の高さを抑えることができる。それに伴って、熱電変換モジュール全体の高さを低くすることができる。 When using a thermoelectric conversion element that is defined by the above formula (1) and is composed of two or more pieces of thermoelectric element divided pieces having the same width (W), the height (L) and width (W) Since the relationship is already defined by the above formula (1), it is difficult to freely change the height (L). However, as shown in FIG. 6, by the width W ₇ of the divided piece 36b included in the same said element 36, a construction is adopted smaller than the width W ₆ of the other of the split pieces 36a, wherein As the width W ₇ is reduced, the height L ₁₅ of the segment 36b can be reduced from the above equation (1), and the height of the element 36 can be reduced. In connection with it, the height of the whole thermoelectric conversion module can be made low.

このような構成の熱電変換モジュールは、熱電変換素子分割片の高さ（Ｌ）と幅（Ｗ）を上記式（１）のように規定することによって、個々の熱電変換素子分割片自体に付与される温度差による熱応力を緩和することができ、熱電変換素子分割片が固着せずに電流流路方向に積み重なることで構成されている熱電変換素子自体の破壊を防止することができる。
また、このような構成の熱電変換モジュールは、前記幅（Ｗ）を小さくするのに伴って、上記式（１）より前記熱電変換素子分割片の高さ（Ｌ）を小さく抑えることができることから、結果的に熱電変換モジュール全体の高さを低くすることができ、個々の前記熱電変換素子分割片自体に付与される温度差による熱応力を緩和しながら熱電変換モジュールの占有体積を小さく抑えることができる。 The thermoelectric conversion module having such a configuration is provided to each thermoelectric conversion element divided piece itself by defining the height (L) and width (W) of the thermoelectric conversion element divided piece as shown in the above formula (1). The thermal stress due to the temperature difference can be alleviated, and the thermoelectric conversion element itself configured by stacking the thermoelectric conversion element segment pieces in the direction of the current flow path without sticking can be prevented.
Moreover, since the thermoelectric conversion module of such a structure can suppress the height (L) of the said thermoelectric conversion element division | segmentation piece small from said Formula (1) as the said width | variety (W) is made small. As a result, the overall height of the thermoelectric conversion module can be reduced, and the occupied volume of the thermoelectric conversion module can be kept small while alleviating the thermal stress due to the temperature difference applied to each of the thermoelectric conversion element segment pieces themselves. Can do.

図７に本発明の実施例１乃至４及び比較例の熱電変換モジュールの一部である、ｐ型熱電変換素子、ｎ型熱電変換素子及び電極の構成を示した。なお、図中白い四辺形がｐ型熱電変換素子又はｐ型熱電変換素子分割片であり、それと対をなす黒い四辺形がｎ型熱電変換素子又はｎ型熱電変換素子分割片である。また、縦縞の四辺形が、前記ｐ型熱電変換素子及び前記ｎ型熱電変換素子をつなぐ電極を表している。 FIG. 7 shows a configuration of a p-type thermoelectric conversion element, an n-type thermoelectric conversion element, and electrodes, which are a part of the thermoelectric conversion modules of Examples 1 to 4 and the comparative example of the present invention. In the figure, the white quadrilateral is the p-type thermoelectric conversion element or the p-type thermoelectric conversion element divided piece, and the black quadrilateral paired with it is the n-type thermoelectric conversion element or the n-type thermoelectric conversion element divided piece. In addition, a vertically striped quadrilateral represents an electrode connecting the p-type thermoelectric conversion element and the n-type thermoelectric conversion element.

［実施例１］
図７（ａ）に示す実施例１は、典型例（図３）を反映したものであり、ｐ型熱電変換素子にはＢａ_８Ｇａ_１８Ｇｅ_２８、ｎ型熱電変換素子にはＢａ_８Ｇａ_１６Ｇｅ_３０を用いた。Ｂａ_８Ｇａ_１８Ｇｅ_２８の破壊強度σ_ＴＥは１１０ＭＰａ、線膨張係数αは１４×１０^−６、弾性率Ｅは９０ＧＰａ、及びＢａ_８Ｇａ_１６Ｇｅ_３０の破壊強度σ_ＴＥは１１０ＭＰａ、線膨張係数αは１４×１０^−６、弾性率Ｅは９０ＧＰａであり、前記ｐ型熱電変換素子及び前記ｎ型熱電変換素子ともに、高温側面から数えて１つ目の熱電変換素子分割片の高温側温度Ｔ_Ｈ、低温側温度Ｔ_Ｃ、初期温度Ｔ_Ｒが（Ｔ_Ｈ，Ｔ_Ｃ，Ｔ_Ｒ）＝（６００℃，５３０℃，２０℃）であり、高温側面から数えて２つ目の熱電変換素子分割片の前記Ｔ_Ｈ、前記Ｔ_Ｃ、前記Ｔ_Ｒが（Ｔ_Ｈ，Ｔ_Ｃ，Ｔ_Ｒ）＝（５３０℃，１００℃，２０℃）であることから、ｐ型熱電変換素子及びｎ型熱電変換素子ともに、高温側面から数えて１つ目の熱電変換素子分割片の高さＬと幅Ｗは（Ｌ，Ｗ）＝（１．２７ｍｍ，４．０ｍｍ）であり、高温側面から数えて２つ目の熱電変換素子分割片の高さＬと幅Ｗは（Ｌ，Ｗ）＝（３．２ｍｍ，４．０ｍｍ）である。 [Example 1]
Example 1 shown in FIG. 7A reflects a typical example (FIG. 3), and Ba ₈ Ga ₁₈ Ge _{28 is used for} a p-type thermoelectric conversion element, and Ba ₈ Ga ₁₆ is used for an n-type thermoelectric conversion element. Ge ₃₀ was used. The breaking strength σ _TE of Ba ₈ Ga ₁₈ Ge ₂₈ is 110 MPa, the linear expansion coefficient α is 14 × 10 ⁻⁶ , the elastic modulus E is 90 GPa, and the breaking strength σ _TE of Ba ₈ Ga ₁₆ Ge ₃₀ is 110 MPa, the linear expansion coefficient α. Is 14 × 10 ⁻⁶ , and the elastic modulus E is 90 GPa. Both the p-type thermoelectric conversion element and the n-type thermoelectric conversion element have a high temperature side temperature T _H of the first thermoelectric conversion element divided piece counted from the high temperature side surface. The low temperature side temperature T _C and the initial temperature T _R are ( _TH , T _C , T _R ) = (600 ° C., 530 ° C., 20 ° C.), and the second thermoelectric conversion element divided piece counting from the high temperature side Since the T _H , T _C , and T _R of ( _TH , T _C , T _R ) = (530 ° C., 100 ° C., 20 ° C.), the p-type thermoelectric conversion element and the n-type thermoelectric conversion element Both are the first thermoelectrics counted from the high temperature side The height L and the width W of the conversion element divided piece are (L, W) = (1.27 mm, 4.0 mm), and the height L and the width of the second thermoelectric conversion element division piece counted from the high temperature side surface. W is (L, W) = (3.2 mm, 4.0 mm).

［実施例２］
図７（ｂ）に示す実施例２は、典型例（図３）を反映したものであるが、ｐ型熱電変換素子及びｎ型熱電変換素子はそれぞれ３つの熱電変換素子分割片が積み重なることで構成されている。上記同様ｐ型熱電変換素子にはＢａ_８Ｇａ_１８Ｇｅ_２８、ｎ型熱電変換素子にはＢａ_８Ｇａ_１６Ｇｅ_３０を用いた。前記ｐ型熱電変換素子及び前記ｎ型熱電変換素子ともに、高温側面から数えて１つ目の熱電変換素子分割片の高温側温度Ｔ_Ｈ、低温側温度Ｔ_Ｃ、初期温度Ｔ_Ｒが（Ｔ_Ｈ，Ｔ_Ｃ，Ｔ_Ｒ）＝（６００℃，５３０℃，２０℃）であり、高温側面から数えて２つ目の熱電変換素子分割片の前記Ｔ_Ｈ、前記Ｔ_Ｃ、前記Ｔ_Ｒが（Ｔ_Ｈ，Ｔ_Ｃ，Ｔ_Ｒ）＝（５３０℃，４６０℃，２０℃）であり、高温側面から数えて３つ目の熱電変換素子分割片の前記Ｔ_Ｈ、前記Ｔ_Ｃ、前記Ｔ_Ｒが（Ｔ_Ｈ，Ｔ_Ｃ，Ｔ_Ｒ）＝（４６０℃，１００℃，２０℃）であることから、ｐ型熱電変換素子及びｎ型熱電変換素子ともに、高温側面から数えて１つ目の熱電変換素子分割片の高さＬと幅Ｗは（Ｌ，Ｗ）＝（１．３ｍｍ，４．０ｍｍ）であり、高温側面から数えて２つ目の熱電変換素子分割片の高さＬと幅Ｗは（Ｌ，Ｗ）＝（１．３ｍｍ，４．０ｍｍ）であり、高温側面から数えて３つ目の熱電変換素子分割片の高さＬと幅Ｗは（Ｌ，Ｗ）＝（２．９ｍｍ，４．０ｍｍ）である。 [Example 2]
Example 2 shown in FIG. 7 (b) reflects the typical example (FIG. 3). However, each of the p-type thermoelectric conversion element and the n-type thermoelectric conversion element is formed by stacking three thermoelectric conversion element divided pieces. It is configured. Similarly to the above, Ba ₈ Ga ₁₈ Ge _{28 was used for} the p-type thermoelectric conversion element, and Ba ₈ Ga ₁₆ Ge ₃₀ was used for the n-type thermoelectric conversion element. Both the p-type thermoelectric conversion elements and the n-type thermoelectric conversion elements, high-temperature side temperature T _H of counting from hot side first thermoelectric conversion element divided _piece, lower side temperature T _C, the initial temperature T _R is (T _H , T _C , T _R ) = (600 ° C., 530 ° C., 20 ° C.), and the T _H , T _C , and T _R of the second thermoelectric conversion element divided piece counted from the high temperature side are (T _{_{_{H, T C, T R)}}} = (530 ℃, 460 ℃, a 20 ° C.), the _{T H} of the third thermoelectric conversion elements divided pieces counted from hot side, wherein _{T C,} wherein _{T R} is ( Since T _H , T _C , T _R ) = (460 ° C., 100 ° C., 20 ° C.), the p-type thermoelectric conversion element and the n-type thermoelectric conversion element are the first thermoelectric conversion elements counted from the high-temperature side. The height L and width W of the split pieces are (L, W) = (1.3 mm, 4.0 mm). The height L and width W of the second thermoelectric conversion element division piece are (L, W) = (1.3 mm, 4.0 mm), and the third thermoelectric conversion element division is counted from the high-temperature side. The height L and width W of the piece are (L, W) = (2.9 mm, 4.0 mm).

［実施例３］
図７（ｃ）に示す実施例３は、典型例を反映し、図５に示したように熱電変換素子分割片同士の界面が電流流路方向に垂直でなく斜めになっている。上記同様ｐ型熱電変換素子にはＢａ_８Ｇａ_１８Ｇｅ_２８、ｎ型熱電変換素子にはＢａ_８Ｇａ_１６Ｇｅ_３０を用いた。前記ｐ型熱電変換素子及び前記ｎ型熱電変換素子ともに、高温側面から数えて１つ目の熱電変換素子分割片の高温側温度Ｔ_Ｈ、低温側温度Ｔ_Ｃ、初期温度Ｔ_Ｒが（Ｔ_Ｈ，Ｔ_Ｃ，Ｔ_Ｒ）＝（６００℃，５３０℃，２０℃）であり、高温側面から数えて２つ目の熱電変換素子分割片の前記Ｔ_Ｈ、前記Ｔ_Ｃ、前記Ｔ_Ｒが（Ｔ_Ｈ，Ｔ_Ｃ，Ｔ_Ｒ）＝（５３０℃，１００℃，２０℃）であることから、ｐ型熱電変換素子及びｎ型熱電変換素子ともに、高温側面から数えて１つ目の熱電変換素子分割片の考慮すべき高さＬと幅Ｗは（Ｌ，Ｗ）＝（１．３ｍｍ，４．０ｍｍ）であり、高温側面から数えて２つ目の熱電変換素子分割片の考慮すべき高さＬと幅Ｗは（Ｌ，Ｗ）＝（３．２ｍｍ，４．０ｍｍ）である。 [Example 3]
Example 3 shown in FIG. 7C reflects a typical example, and as shown in FIG. 5, the interface between the thermoelectric conversion element divided pieces is not perpendicular to the current flow path direction but is slanted. Similarly to the above, Ba ₈ Ga ₁₈ Ge _{28 was used for} the p-type thermoelectric conversion element, and Ba ₈ Ga ₁₆ Ge ₃₀ was used for the n-type thermoelectric conversion element. Both the p-type thermoelectric conversion elements and the n-type thermoelectric conversion elements, high-temperature side temperature T _H of counting from hot side first thermoelectric conversion element divided _piece, lower side temperature T _C, the initial temperature T _R is (T _H , T _C , T _R ) = (600 ° C., 530 ° C., 20 ° C.), and the T _H , T _C , and T _R of the second thermoelectric conversion element divided piece counted from the high temperature side are (T _{Since H 1} , T _C , T _R ) = (530 ° C., 100 ° C., 20 ° C.), both the p-type thermoelectric conversion element and the n-type thermoelectric conversion element are divided from the first thermoelectric conversion element counted from the high temperature side. The height L and width W to be considered of the piece are (L, W) = (1.3 mm, 4.0 mm), and the height to be considered of the second thermoelectric conversion element divided piece counted from the high temperature side surface. L and width W are (L, W) = (3.2 mm, 4.0 mm).

［実施例４］
図７（ｄ）に示す実施例４は、変形例（図６）を反映したものであり、ｎ型熱電変換素子は２片の熱電変換素子分割片から構成されるのに対し、ｐ型熱電変換素子は１片の素子のみから成る。また、上記同様ｐ型熱電変換素子にはＢａ_８Ｇａ_１８Ｇｅ_２８、ｎ型熱電変換素子にはＢａ_８Ｇａ_１６Ｇｅ_３０を用いた。前記ｐ型熱電変換素子の高温側温度Ｔ_Ｈ、低温側温度Ｔ_Ｃ、初期温度Ｔ_Ｒが（Ｔ_Ｈ，Ｔ_Ｃ，Ｔ_Ｒ）＝（６００℃，１００℃，２０℃）であり、ｎ型熱電変換素子を構成する高温側面から数えて１つ目の熱電変換素子分割片の前記Ｔ_Ｈ、前記Ｔ_Ｃ、初期温度Ｔ_Ｒが（Ｔ_Ｈ，Ｔ_Ｃ，Ｔ_Ｒ）＝（６００℃，５３０℃，２０℃）であり、高温側面から数えて２つ目の熱電変換素子分割片の前記Ｔ_Ｈ、前記Ｔ_Ｃ、前記Ｔ_Ｒが（Ｔ_Ｈ，Ｔ_Ｃ，Ｔ_Ｒ）＝（５３０℃，１００℃，２０℃）であることから、ｐ型熱電変換素子の高さＬと幅Ｗは（Ｌ，Ｗ）＝（４．０ｍｍ，４．０ｍｍ）であり、ｎ型熱電変換素子を構成する高温側面から数えて１つ目の熱電変換素子分割片の高さＬと幅Ｗは（Ｌ，Ｗ）＝（１．２７ｍｍ，４．０ｍｍ）であり、高温側面から数えて２つ目の熱電変換素子分割片の高さＬと幅Ｗは（Ｌ，Ｗ）＝（２．７ｍｍ，３．４ｍｍ）である。 [Example 4]
Example 4 shown in FIG. 7 (d) reflects the modification (FIG. 6). The n-type thermoelectric conversion element is composed of two pieces of thermoelectric conversion element divided pieces, whereas the p-type thermoelectric element. The conversion element consists of only one piece of element. Further, similarly to the above p-type thermoelectric conversion elements in _Ba 8 _Ga 18 _{Ge 28,} n-type thermoelectric conversion element using the _Ba 8 _Ga 16 _{Ge 30.} The p-type thermoelectric conversion element has a high temperature side temperature T _H , a low temperature side temperature T _C , and an initial temperature T _R (T _H , T _C , T _R ) = (600 ° C., 100 ° C., 20 ° C.), and n-type The T _H , T _C , and initial temperature T _R of the first thermoelectric conversion element divided piece counting from the high temperature side constituting the thermoelectric conversion element are (T _H , T _C , T _R ) = (600 ° C., 530). ° C., a 20 ° C.), the _{T H} of counting from hot side the second thermoelectric conversion element divided pieces, the _{T C,} wherein _{T R} is _{_{_{(T H, T C, T}}} R) = (530 ℃, (100 ° C., 20 ° C.), the height L and width W of the p-type thermoelectric conversion element are (L, W) = (4.0 mm, 4.0 mm), which constitutes the n-type thermoelectric conversion element. The height L and width W of the first thermoelectric conversion element segment counted from the high temperature side are (L, W) = (1.27 mm, 4.0 mm). Ri, height L and width W of the second thermoelectric conversion element split pieces counted from the high temperature side is (L, W) = (2.7mm, 3.4mm).

［比較例］
図７（ｅ）に示す比較例は、従来通り、ｐ型熱電変換素子及びｎ型熱電変換素子のどちらも１片の素子のみから成るものを用いた。また、上記同様ｐ型熱電変換素子にはＢａ_８Ｇａ_１８Ｇｅ_２８、ｎ型熱電変換素子にはＢａ_８Ｇａ_１６Ｇｅ_３０を用いた。前記ｐ型熱電変換素子及び前記ｎ型熱電変換素子ともに、高温側温度Ｔ_Ｈ、低温側温度Ｔ_Ｃ、初期温度Ｔ_Ｒが（Ｔ_Ｈ，Ｔ_Ｃ，Ｔ_Ｒ）＝（６００℃，１００℃，２０℃）であり、ｐ型熱電変換素子及びｎ型熱電変換素子ともに、高さＬと幅Ｗは（Ｌ，Ｗ）＝（３．４ｍｍ，４．０ｍｍ）である。 [Comparative example]
In the comparative example shown in FIG. 7 (e), a p-type thermoelectric conversion element and an n-type thermoelectric conversion element each composed of only one piece were used as in the past. Further, similarly to the above p-type thermoelectric conversion elements in _Ba 8 _Ga 18 _{Ge 28,} n-type thermoelectric conversion element using the _Ba 8 _Ga 16 _{Ge 30.} In both the p-type thermoelectric conversion element and the n-type thermoelectric conversion element, the high temperature side temperature T _H , the low temperature side temperature T _C , and the initial temperature T _R are ( _TH , T _C , T _R ) = (600 ° C., 100 ° C., And the height L and the width W are (L, W) = (3.4 mm, 4.0 mm) for both the p-type thermoelectric conversion element and the n-type thermoelectric conversion element.

なお、実施例１乃至４及び比較例の全てにおいて、以下の共通する条件を用いた。すなわち、高温側電極にはＴｉ_２Ｃｕ_３を用い、拡散接合により熱電変換素子と接合した。低温側電極には銅を用い、低温側電極と接する熱電変換素子の部位にはＡｕメッキ、Ｎｉメッキ、Ａｕメッキの順にメッキを施した後、はんだ付けにより低温側電極と接合した。熱電変換素子を構成する熱電変換素子分割片同士は接合せず、互いに押し付け合い、さらに熱電変換素子分割片同士の界面にすべりやすく電気的導通を妨げない材料である銅を塗布することで電気的な導通を取った。さらに、一対の窒化アルミを基板として、電極の両側から挟持し、熱電変換モジュールを作製した。 In all of Examples 1 to 4 and the comparative example, the following common conditions were used. That is, Ti ₂ Cu ₃ was used for the high temperature side electrode and joined to the thermoelectric conversion element by diffusion bonding. Copper was used for the low temperature side electrode, and the portion of the thermoelectric conversion element in contact with the low temperature side electrode was plated in the order of Au plating, Ni plating, and Au plating, and then joined to the low temperature side electrode by soldering. The thermoelectric conversion element segment pieces constituting the thermoelectric conversion element are not bonded to each other, pressed against each other, and further applied by applying copper, which is a material that is easy to slide on the interface between the thermoelectric conversion element segment pieces and does not hinder electrical conduction. Took a good continuity. Further, a thermoelectric conversion module was fabricated by sandwiching a pair of aluminum nitride from both sides of the electrode as a substrate.

一般的な熱電変換モジュールの層構成を模式的に示した図である。It is the figure which showed typically the layer structure of the general thermoelectric conversion module. ２片の熱電変換素子分割片と電流流路方向とを示した断面模式図である。It is the cross-sectional schematic diagram which showed the 2 piece thermoelectric conversion element division | segmentation piece and the electric current flow path direction. 本発明の熱電変換モジュールの典型例の断面模式図である。It is a cross-sectional schematic diagram of the typical example of the thermoelectric conversion module of this invention. 温度差による方形構造物の変形についての説明図である。It is explanatory drawing about a deformation | transformation of the square structure by a temperature difference. 熱電変換素子分割片同士の界面が電流流路方向に斜めになっている場合を示した断面模式図である。It is the cross-sectional schematic diagram which showed the case where the interface of thermoelectric conversion element division | segmentation pieces is slanting in the direction of a current flow path. 本発明の熱電変換モジュールの変形例の断面模式図である。It is a cross-sectional schematic diagram of the modification of the thermoelectric conversion module of this invention. 本発明の実施例１乃至４及び比較例の熱電変換モジュールの一部である、ｐ型熱電変換素子、ｎ型熱電変換素子及び電極の構成を示した図である。It is the figure which showed the structure of the p-type thermoelectric conversion element, n-type thermoelectric conversion element, and electrode which are some thermoelectric conversion modules of Examples 1-4 of this invention, and a comparative example. 本発明から外れる例を示す図であり、２つの熱電変換素子分割片の界面が、電流流路方向と平行であることを示す図である。It is a figure which shows the example which deviates from this invention, and is a figure which shows that the interface of two thermoelectric conversion element division | segmentation pieces is parallel to a current flow path direction.

符号の説明Explanation of symbols

１…ｐ型熱電変換素子
２…ｎ型熱電変換素子
３…電極
４…基板
５…端の電極
６…電流流路方向
７…電流流路方向上流の熱電変換素子分割片
８…電流流路方向下流の熱電変換素子分割片
９…熱電変換素子分割片
１１、１２…基板
１３、１４…電極
１５…ｐ型熱電変換素子
１５ａ、１５ｂ…ｐ型熱電変換素子分割片
１６…ｎ型熱電変換素子
１６ａ、１６ｂ…ｎ型熱電変換素子分割片
２１…方形の構造物
２２…変形した構造物
３１、３２…基板
３３、３４…電極
３５…ｐ型熱電変換素子
３６…ｎ型熱電変換素子
３６ａ、３６ｂ…ｎ型熱電変換素子分割片
１００…熱電変換モジュール
２００…熱電変換モジュール
３００…熱電変換モジュール DESCRIPTION OF SYMBOLS 1 ... p-type thermoelectric conversion element 2 ... n-type thermoelectric conversion element 3 ... Electrode 4 ... Board | substrate 5 ... End electrode 6 ... Current flow path direction 7 ... Thermoelectric conversion element division | segmentation piece 8 upstream of a current flow path direction ... Current flow path direction Downstream thermoelectric conversion element division piece 9 ... thermoelectric conversion element division piece 11, 12 ... substrate 13, 14 ... electrode 15 ... p-type thermoelectric conversion element 15a, 15b ... p-type thermoelectric conversion element division piece 16 ... n-type thermoelectric conversion element 16a , 16b ... n-type thermoelectric conversion element segment 21 ... rectangular structure 22 ... deformed structure 31, 32 ... substrate 33, 34 ... electrode 35 ... p-type thermoelectric conversion element 36 ... n-type thermoelectric conversion element 36a, 36b ... n-type thermoelectric conversion element segment 100 ... thermoelectric conversion module 200 ... thermoelectric conversion module 300 ... thermoelectric conversion module

Claims

一対の電極と、該一対の電極間に設けられた熱電変換素子を具備し、
少なくとも１つの前記熱電変換素子が、２片以上の熱電変換素子分割片同士が界面において固着せずに電流流路方向に積み重なることで構成されており、且つ、
前記熱電変換素子分割片の高さ（Ｌ）と当該熱電変換素子分割片の幅（Ｗ）とが、下記式（１）の関係を満たすことを特徴とする、熱電変換モジュール。

（ただし、上記式（１）中、σ_ＴＥは破壊強度、αは線膨張係数、Ｅは弾性率、Ｔ_Ｈは前記熱電変換素子分割片の高温側温度、Ｔ_Ｒは前記熱電変換素子分割片の初期温度、Ｔ_Ｃは前記熱電変換素子分割片の低温側温度を示す。） Comprising a pair of electrodes and a thermoelectric conversion element provided between the pair of electrodes;
At least one of the thermoelectric conversion elements is constituted by stacking two or more pieces of thermoelectric conversion element pieces in the direction of the current flow path without being fixed at the interface, and
The thermoelectric conversion module, wherein a height (L) of the thermoelectric conversion element divided piece and a width (W) of the thermoelectric conversion element divided piece satisfy the relationship of the following formula (1).

(However, in the above formula (1), sigma _TE is breaking strength, alpha linear expansion coefficient, E is the elastic modulus, T _H is a high temperature-side temperature of the thermoelectric conversion elements divided pieces, T _R is the thermoelectric conversion elements divided piece initial temperature of, T _C denotes a lower side temperature of the thermoelectric conversion elements divided pieces.)

同じ前記熱電変換素子に含まれる前記熱電変換素子分割片のうち、少なくとも１つの当該熱電変換素子分割片の前記幅（Ｗ）が、他の前記熱電変換素子分割片の前記幅（Ｗ）よりも小さい、請求項１に記載の熱電変換モジュール。 Among the thermoelectric conversion element divided pieces included in the same thermoelectric conversion element, the width (W) of at least one of the thermoelectric conversion element divided pieces is larger than the width (W) of the other thermoelectric conversion element divided pieces. The thermoelectric conversion module according to claim 1, which is small.