JP3056047B2 - Thermal stress relaxation pad for thermoelectric conversion element and thermoelectric conversion element - Google Patents
Thermal stress relaxation pad for thermoelectric conversion element and thermoelectric conversion elementInfo
- Publication number
- JP3056047B2 JP3056047B2 JP6339917A JP33991794A JP3056047B2 JP 3056047 B2 JP3056047 B2 JP 3056047B2 JP 6339917 A JP6339917 A JP 6339917A JP 33991794 A JP33991794 A JP 33991794A JP 3056047 B2 JP3056047 B2 JP 3056047B2
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- thermal stress
- thermoelectric conversion
- conversion element
- stress relaxation
- copper
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Description
【０００１】[0001]
【産業上の利用分野】本発明は、ゼーベック効果を利用
して熱エネルギーを直接電気エネルギーに変換する熱電
変換素子及びこの素子用の熱応力緩和パッドの改良に関
する。更に、詳細に述べれば、大規模なエネルギー変換
システムに大量に用いられる高出力の熱電変換素子に好
適な熱応力緩和パッドに関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoelectric conversion element for converting heat energy directly into electric energy by utilizing the Seebeck effect and to an improvement of a thermal stress relaxation pad for the element. More specifically, the present invention relates to a thermal stress relaxation pad suitable for a high-output thermoelectric conversion element used in large quantities in a large-scale energy conversion system.
【０００２】[0002]
【従来の技術】従来の熱電変換素子に用いられる熱応力
緩和パッドとしては、米国の宇宙用原子炉の熱電変換素
子用に開発されたものがある。これは、１インチ四方の
ニオブ（Ｎｂ）の板に直径数ミクロンのニオブのフィラ
メントを１千万本程度植え付けたものである。そして、
このパッドを使用した熱電変換素子は、図５のように、
シリコン−ゲルマニウム（ＳｉＧｅ）素子を熱電素子２
１とし、その両側にニオブのフィラメントによる熱応力
緩和パッド２２，２２を配置しているものである。な
お、この熱電変換素子の詳細構造は、高温側の加熱ダク
ト及び低温側の冷却ダクトにそれぞれ接触するサファイ
アからなる電気絶縁材２３，２３、その内側に配置され
る熱応力緩和パッド２２，２２、ガラスからなる電気絶
縁材２４，２４、タングステンからなる電極２５，２
５、そして更にその内側に配置され熱電素子２１と接触
するグラファイトからなる電極２６，２６とを有する構
造となっている。ここで、熱応力緩和パッド２２，２２
は、熱応力緩和及び熱伝導の両機能を果たしている。2. Description of the Related Art As a thermal stress relaxation pad used in a conventional thermoelectric conversion element, there is a pad developed for a thermoelectric conversion element of a space reactor in the United States. In this method, about 10 million niobium filaments having a diameter of several microns are planted on a 1-inch square niobium (Nb) plate. And
The thermoelectric conversion element using this pad is as shown in FIG.
A silicon-germanium (SiGe) element is replaced with a thermoelectric element 2
1, and thermal stress relaxation pads 22 and 22 made of niobium filaments are arranged on both sides. The detailed structure of the thermoelectric conversion element is as follows: an electrical insulating material 23, 23 made of sapphire that comes into contact with the heating duct on the high temperature side and the cooling duct on the low temperature side, respectively; Electrical insulating materials 24 and 24 made of glass, electrodes 25 and 2 made of tungsten
5, and further, electrodes 26 and 26 made of graphite which are arranged inside and are in contact with the thermoelectric element 21. Here, the thermal stress relaxation pads 22, 22
Performs both functions of thermal stress relaxation and heat conduction.
【０００３】[0003]
【発明が解決しようとする課題】しかしながら、従来の
ニオブのフィラメントによる熱応力緩和パッド２２，２
２は、非常に精細な構造で製造に時間とコストがかかっ
ている。また、熱応力に対し、直径数ミクロンのフィラ
メントでは十分対応できず、寿命は短いものとなってい
る。However, conventional thermal stress relaxation pads 22 and 2 made of niobium filaments are used.
No. 2 has a very fine structure and requires time and cost for manufacturing. Further, a filament having a diameter of several microns cannot sufficiently cope with thermal stress, and the life is short.
【０００４】本発明は、構造が簡単で熱応力への緩和力
が大きく、しかも寿命が長い熱電変換素子用熱応力緩和
パッド及び熱電変換素子を提供することを目的とする。An object of the present invention is to provide a thermal stress relaxation pad for a thermoelectric conversion element and a thermoelectric conversion element which have a simple structure, have a large relaxing power to thermal stress, and have a long life.
【０００５】[0005]
【課題を解決するための手段】かかる目的を達成するた
め、請求項１の発明は、電気絶縁材料と熱応力緩和材料
の組成割合を徐々に変化させた熱伝導性の傾斜機能材料
で熱電変換素子用熱応力緩和パッドを形成している。な
お、この明細書において述べる傾斜機能材料とは、複数
の材料から構成されその組成割合が徐々に変わる部分を
保有する部材を指すものとする。In order to achieve the above object, a first aspect of the present invention is a thermoelectrically functionally graded material in which the composition ratio of an electrically insulating material and a thermal stress relaxation material is gradually changed. A thermal stress relaxation pad for the device is formed. Note that the functionally graded material described in this specification refers to a member that is composed of a plurality of materials and has a portion whose composition ratio changes gradually.
【０００６】加えて、請求項２の発明は、請求項１記載
の熱電変換素子用熱応力緩和パッドにおいて、電気絶縁
材料として窒化珪素を、熱応力緩和材料としてパラジウ
ムまたは銅を使用している。According to a second aspect of the present invention, in the thermal stress relaxation pad for a thermoelectric conversion element according to the first aspect, silicon nitride is used as an electrical insulating material and palladium or copper is used as a thermal stress relaxing material.
【０００７】また、請求項３の発明は、熱電素子の電極
と熱源との間に、電気絶縁材料と熱応力緩和材料の組成
割合を徐々に変化させた熱伝導性の傾斜機能材料を挟ん
でいる。更に、請求項４の発明は、加熱ダクトと冷却ダ
クトの間に挟んで使用され、両ダクトからの熱応力を緩
和する熱応力緩和パッドを有する熱電変換素子におい
て、熱応力緩和パッドを電気絶縁材料と熱応力緩和材料
の組成割合を徐々に変化させた熱伝導性の傾斜機能材料
で構成している。加えて、請求項５の発明は、請求項３
または４記載の熱電変換素子において、電気絶縁材料と
して窒化珪素を、熱応力緩和材料としてパラジウムまた
は銅を使用している。According to a third aspect of the present invention, a thermally conductive functionally graded material in which the composition ratio of an electrically insulating material and a thermal stress relaxation material is gradually changed is sandwiched between an electrode of a thermoelectric element and a heat source. I have. Further, the invention according to claim 4 is a thermoelectric conversion element which is used between a heating duct and a cooling duct and has a thermal stress relaxation pad for relaxing thermal stress from both ducts. And a thermally conductive functionally graded material in which the composition ratio of the thermal stress relaxation material is gradually changed. In addition, the invention of claim 5 is based on claim 3
Alternatively, in the thermoelectric conversion element described in 4, the silicon nitride is used as an electrical insulating material, and palladium or copper is used as a thermal stress relaxing material.
【０００８】また、請求項６の発明は、請求項４記載の
熱電変換素子において、加熱ダクト側の熱応力緩和材料
としてパラジウムを、冷却ダクト側の熱応力緩和材料と
して銅を使用している。According to a sixth aspect of the present invention, in the thermoelectric conversion element according to the fourth aspect, palladium is used as the thermal stress relaxing material on the heating duct side and copper is used as the thermal stress relaxing material on the cooling duct side.
【０００９】[0009]
【作用】したがって、本発明の熱電変換素子用熱応力緩
和パッドは、電気絶縁材料と熱応力緩和材料の組成割合
が徐々に変化する傾斜機能材料となっているので、この
傾斜機能材料内を伝わる熱による応力は、特定部分に集
中せず分散する。Therefore, the thermal stress relaxation pad for a thermoelectric conversion element of the present invention is a functionally graded material in which the composition ratio of the electrically insulating material and the thermal stress mitigating material changes gradually, and is transmitted through this functionally graded material. The thermal stress is not concentrated on a specific portion but is dispersed.
【００１０】また、熱応力緩和材料として、熱伝導率が
大きいパラジウムまたは銅を使用しているので高い熱流
束を電極に伝えることができる。また、弾性定数の小さ
いパラジウムまたは銅を使用しているので、熱応力が小
さく、電気絶縁材料としての窒化珪素とのなじみが良
く、熱応力を充分緩和する。Further, since palladium or copper having a high thermal conductivity is used as the thermal stress relaxation material, a high heat flux can be transmitted to the electrode. Further, since palladium or copper having a small elastic constant is used, the thermal stress is small, and it is well compatible with silicon nitride as an electric insulating material, and the thermal stress is sufficiently reduced.
【００１１】更に、熱電素子の電極と熱源との間に傾斜
機能材料を挟んだ熱電変換素子や、加熱ダクトと冷却ダ
クトの間に挟んで使用される熱電変換素子においては、
一方の熱源の熱や加熱ダクト側の熱は、傾斜機能材料内
を伝わり一方の電極に伝わる。ここで、熱応力緩和材料
として、熱伝導率が大きいパラジウムまたは銅を使用す
ることにより高い熱流束を電極に伝えることができる。
また、弾性定数の小さいパラジウムまたは銅を使用する
ことにより、熱応力は少なくなり、電気絶縁材料として
の窒化珪素とのなじみが良いものとなり、熱応力を充分
緩和する。Further, in a thermoelectric conversion element in which a functionally graded material is interposed between an electrode of a thermoelectric element and a heat source, or in a thermoelectric conversion element used between a heating duct and a cooling duct,
The heat of one heat source and the heat on the heating duct side are transmitted through the functionally gradient material to one electrode. Here, high heat flux can be transmitted to the electrode by using palladium or copper having a large thermal conductivity as the thermal stress relaxation material.
Further, by using palladium or copper having a small elastic constant, the thermal stress is reduced, the compatibility with silicon nitride as an electrical insulating material is improved, and the thermal stress is sufficiently reduced.
【００１２】加えて、加熱ダクトと冷却ダクトの間に挟
んで使用される熱電変換素子においては、加熱ダクト側
の熱は、熱応力緩和材料として銅より融点の高いパラジ
ウムを使用した傾斜機能材料内を伝わり一方の電極に伝
わり、更に熱応力緩和材料として銅を使用した傾斜機能
材料内を伝わり他方の電極に伝わる。このようにして、
高温側に銅の融点より温度の高い熱源がきても対応する
ことができる。In addition, in a thermoelectric conversion element used between a heating duct and a cooling duct, heat on the side of the heating duct is transferred to a functionally graded material using palladium having a higher melting point than copper as a thermal stress relaxation material. To the other electrode, and further to the other electrode through the functionally gradient material using copper as a thermal stress relaxation material. In this way,
Even if a heat source whose temperature is higher than the melting point of copper comes to the high temperature side, it can be handled.
【００１３】[0013]
【実施例】以下、本発明の構成を図面に示す実施例に基
づいて詳細に説明する。DESCRIPTION OF THE PREFERRED EMBODIMENTS The construction of the present invention will be described below in detail with reference to the embodiments shown in the drawings.
【００１４】図１及び図２に本発明の熱電変換素子用熱
応力緩和パッド及び熱電変換素子の一実施例を示す。こ
の熱電変換素子１０は、宇宙用原子炉における直接発電
システムに使用されるものである。そして、この熱電変
換素子１０の主要構成は、シリコン−ゲルマニウム（Ｓ
ｉＧｅ）半導体素子を熱電素子１とし、その両側に本発
明による熱応力緩和パッド２ａ，２ｂを配置しているも
のである。FIGS. 1 and 2 show an embodiment of a thermal stress relaxation pad for a thermoelectric conversion element and a thermoelectric conversion element according to the present invention. This thermoelectric conversion element 10 is used for a direct power generation system in a space nuclear reactor. The main configuration of the thermoelectric conversion element 10 is silicon-germanium (S
iGe) A semiconductor element is a thermoelectric element 1, and thermal stress relaxation pads 2a and 2b according to the present invention are arranged on both sides thereof.
【００１５】この熱電変換素子１０の高温側の詳細構造
は、高温側の加熱ダクト（図示省略）に接触し熱伝導性
及び電気絶縁性を有するサファイアからなる電気絶縁材
３ａ、その内側に配置されるグラファイトからなる熱応
力緩和材４ａ、更にその内側に配置されるパラジウムと
窒化珪素からなる熱伝導性の傾斜機能材料２ａ及び熱電
素子１と接触するグラファイトからなる電極５ａとを有
する構造となっている。一方、低温側の詳細構造は、低
温側の冷却ダクト（図示省略）に接触するサファイアか
らなる電気絶縁材３ｂ、その内側に配置されるグラファ
イトからなる熱応力緩和材４ｂ、更にその内側に配置さ
れる銅と窒化珪素からなる熱伝導性の傾斜機能材料２ｂ
及び熱電素子１と接触するグラファイトからなる電極５
ｂとを有する構造となっている。なお、加熱ダクト面の
温度は約８４０℃程度で、冷却ダクト面の温度は約５３
０℃程度である。The detailed structure on the high-temperature side of the thermoelectric conversion element 10 is an electric insulating material 3a made of sapphire having thermal conductivity and electric insulation, which is in contact with a heating duct (not shown) on the high-temperature side, and is disposed inside thereof. Having a thermal stress relaxation material 4a made of graphite, a thermally functional gradient material 2a made of palladium and silicon nitride, and an electrode 5a made of graphite in contact with the thermoelectric element 1. I have. On the other hand, the detailed structure on the low-temperature side is composed of an electrical insulating material 3b made of sapphire in contact with a cooling duct (not shown) on the low-temperature side, a thermal stress relieving material 4b made of graphite disposed on the inside, and further disposed on the inside. Conductive functionally graded material 2b consisting of copper and silicon nitride
And electrode 5 made of graphite in contact with thermoelectric element 1
b. The temperature of the heating duct surface is about 840 ° C., and the temperature of the cooling duct surface is about 53 ° C.
It is about 0 ° C.
【００１６】ここで、加熱ダクト側の熱応力緩和材料と
してパラジウムを、冷却ダクト側の熱応力緩和材料とし
て銅を使用しているのは、次のとおりである。即ち、表
１のパラジウムと銅の物性値に示されるように、共に熱
伝導率が大きく弾性定数が小さい材料であることが熱応
力緩和材料として使用した理由である。そして、特に銅
は熱伝導率に対する弾性定数の比率が非常に小さく、高
い熱伝導性を維持しながら熱応力の緩和が可能な材料で
あり、非常に好ましいものである。しかしながら、銅の
融点はそれほど高くはない。このため、宇宙用原子炉等
高温側の使用温度が銅の融点を超えるものでは、銅を使
用できないので、銅は低温側のみに使用し、高温側には
銅についで性能の優れたパラジウムを使用したのであ
る。Here, the use of palladium as the thermal stress relaxing material on the heating duct side and copper as the thermal stress relaxing material on the cooling duct side is as follows. That is, as shown in the physical property values of palladium and copper in Table 1, the reason for using the material as a thermal stress relaxation material is that the material has a large thermal conductivity and a small elastic constant. In particular, copper is a very preferable material because it has a very small ratio of the elastic constant to the thermal conductivity and is capable of relaxing thermal stress while maintaining high thermal conductivity. However, the melting point of copper is not very high. Therefore, copper cannot be used if the operating temperature on the high-temperature side, such as a space reactor, exceeds the melting point of copper.Therefore, copper is used only on the low-temperature side, and palladium, which has excellent performance after copper, is used on the high-temperature side. I used it.
【００１７】[0017]
【表１】 [Table 1]
【００１８】また、熱応力緩和パッドとなる傾斜機能材
料２ａは、パラジウムの割合が多くなる側を熱応力緩和
材４ａ側に来るように配置され、一方、熱応力緩和パッ
ドとなる傾斜機能材料２ｂは、銅の割合が多くなる側を
熱応力緩和材４ｂ側に来るように配置されている。これ
は、電極５ａ，５ｂとの電気的な絶縁を考慮したためで
ある。また、熱応力の影響を考慮し、この熱電変換素子
１０の高温側の各部材の厚さを、低温側の各部材の厚さ
に比べ薄くしている。また、熱応力緩和パッドとなる傾
斜機能材料２ａ，２ｂは、熱応力緩和及び熱伝導の両機
能を果たしている。The functionally graded material 2a serving as a thermal stress relaxation pad is disposed so that the side where the proportion of palladium increases is closer to the thermal stress relaxation material 4a, while the functionally graded material 2b serving as a thermal stress relaxation pad is arranged. Are arranged such that the side where the proportion of copper is increased comes to the thermal stress relaxation material 4b side. This is because electrical insulation from the electrodes 5a and 5b is considered. Further, in consideration of the influence of thermal stress, the thickness of each member on the high temperature side of the thermoelectric conversion element 10 is made smaller than the thickness of each member on the low temperature side. In addition, the functionally gradient materials 2a and 2b serving as thermal stress relaxation pads fulfill both functions of thermal stress relaxation and heat conduction.
【００１９】なお、パラジウムと窒化珪素からなる熱伝
導性の傾斜機能材料２ａ及び銅と窒化珪素からなる熱伝
導性の傾斜機能材料２ｂの各製造は次のとおり行う。即
ち、パラジウム、銅及び窒化珪素はいずれも粉末が入手
可能であり、粉末冶金法により製造する。この製造方法
は、まず、２本のノズルから粉末を噴射する装置を使用
し、そのノズルの一方からパラジウムまたは銅を噴射
し、他方のノズルから窒化珪素を噴射し、両ノズルの噴
射比率を制御することにより組成割合を変化させたペレ
ット（粉末の塊）を作成する。次に、このペレットを炉
で焼結することにより傾斜機能材料２ａ，２ｂを得る。The production of the thermally conductive functionally gradient material 2a made of palladium and silicon nitride and the thermally conductive functionally gradient material 2b made of copper and silicon nitride are performed as follows. That is, powders of palladium, copper, and silicon nitride are all available, and are manufactured by powder metallurgy. This manufacturing method first uses a device that injects powder from two nozzles, injects palladium or copper from one of the nozzles, injects silicon nitride from the other nozzle, and controls the injection ratio of both nozzles Thus, pellets (lumps of powder) having different composition ratios are prepared. Next, the pellets are sintered in a furnace to obtain functionally gradient materials 2a and 2b.
【００２０】このようにして製造されるパラジウムと窒
化珪素からなる熱伝導性の傾斜機能材料２ａの構成及び
熱応力分布は、図２のとおりとなる。即ち、窒化珪素が
１００％となる電気絶縁材料部２ｄとパラジウムが１０
０％となる熱応力緩和材料部２ｅとの間に組成割合が変
化する傾斜組成部２ｃが配置される構造となる。そし
て、組成割合が変化する傾斜組成部２ｃの熱応力分布
は、窒化珪素材６とパラジウム材７を単に接合した場合
の接合面８の熱応力分布（図３参照）に比べ分散する。
窒化珪素は非常に硬い材料であるが、パラジウムと接合
させずに、このように組成割合を徐々に変化させた熱伝
導性の傾斜機能材料２ａとすることにより熱応力の緩和
が可能となる。この点は、銅と窒化珪素からなる熱伝導
性の傾斜機能材料２ｂにおいても同様である。The structure and thermal stress distribution of the thermally conductive functionally gradient material 2a made of palladium and silicon nitride manufactured as described above are as shown in FIG. That is, the electrical insulating material portion 2d in which silicon nitride is 100% and palladium are 10%.
A gradient composition portion 2c whose composition ratio changes is arranged between the thermal stress relaxation material portion 2e and 0%. The thermal stress distribution of the gradient composition portion 2c in which the composition ratio changes is more dispersed than the thermal stress distribution of the bonding surface 8 when the silicon nitride material 6 and the palladium material 7 are simply bonded (see FIG. 3).
Although silicon nitride is a very hard material, the thermal stress can be reduced by using the thermally conductive functionally graded material 2a whose composition ratio is gradually changed without joining with palladium. This applies to the thermally conductive functionally gradient material 2b made of copper and silicon nitride.
【００２１】なお、上述の実施例は、本発明の好適な実
施例の一例ではあるが、これに限定されるものではな
く、本発明の要旨を逸脱しない範囲において種々変形実
施可能である。例えば、本発明の用途としては、宇宙用
原子炉における直接発電システムの他に、自動車等のエ
ンジンや工場の炉等から排気される高温のガスに使用し
たり、工場や一般の原子炉等から排出される各種の高温
排熱水等に適用することができる。Although the above embodiment is an example of a preferred embodiment of the present invention, the present invention is not limited to this, and various modifications can be made without departing from the spirit of the present invention. For example, the application of the present invention is not only a direct power generation system in a space nuclear reactor, but also a high-temperature gas exhausted from an engine of a car or the like, a furnace of a factory, or the like from a plant or a general nuclear reactor. The present invention can be applied to various kinds of discharged high-temperature exhaust heat water.
【００２２】また、熱電素子１としては、熱エネルギー
を電力に変換することが可能なものであれば他のもので
も良い。例えば、ＳｉＧｅの他に、ＦｅＳｉ2、ＣｒＳ
ｉ2等の金属珪化物、ＮｉＯ等の金属酸化物、鉛−テル
ル（ＰｂＴｅ）やビスマス−テルル（ＢｉＴｅ）等のテ
ルル系の半導体等があり、使用温度領域等に応じて適宜
選択される。また、これらの物質をアモルファス状の薄
膜とすることも可能である。The thermoelectric element 1 may be any other element that can convert thermal energy into electric power. For example, in addition to SiGe, FeSi 2 , CrS
There are metal silicides such as i 2 , metal oxides such as NiO, tellurium-based semiconductors such as lead-tellurium (PbTe) and bismuth-tellurium (BiTe), etc., which are appropriately selected according to the operating temperature range and the like. Further, these substances can be made into an amorphous thin film.
【００２３】更に、熱伝導性の傾斜機能材料２ａ，２ｂ
を構成する電気絶縁材料としては、窒化珪素の他にアル
ミナ等各種の電気絶縁材料を採用できる。ただし、窒化
珪素や炭化珪素等の各種のセラミックは、熱伝導性が良
く、熱に対しての変形が少なくしかも電気絶縁性が優れ
ているため最も好ましい材料といえる。また、熱伝導性
の傾斜機能材料２ａ，２ｂを構成する熱応力緩和材料と
しては、パラジウムや銅の他、各種の金属材料を採用で
きるが、その中では、熱伝導率が大きく弾性定数の小さ
いもの、即ち熱伝導率に対する弾性定数の比率がより小
さいものがより好ましい。Further, the thermally conductive functionally gradient materials 2a, 2b
Various electrical insulating materials such as alumina can be employed as well as silicon nitride. However, various ceramics such as silicon nitride and silicon carbide are the most preferable materials because of their good thermal conductivity, little deformation to heat, and excellent electrical insulation. Further, as the thermal stress relieving material constituting the thermally conductive functionally gradient materials 2a and 2b, various metal materials can be adopted in addition to palladium and copper, but among them, the thermal conductivity is large and the elastic constant is small. Those having a smaller elastic modulus to thermal conductivity ratio are more preferred.
【００２４】また、電気絶縁材３ａ，３ｂとその内側に
配置される熱応力緩和材４ａ，４ｂを省き、熱伝導性の
傾斜機能材料２ａ，２ｂを最外部に来るようにしても良
い。その場合、図４に示すように、窒化珪素等の電気絶
縁物が１００％の電気絶縁材料部２ｄ，２ｄを両側に配
置し、その各内側に組成割合が変化する傾斜組成部２
ｃ，２ｃを、そして中央にパラジウムや銅等の熱応力緩
和材が１００％となる熱応力緩和材料部２ｅを設けるよ
うにすると両側に電気絶縁材が来て好ましいものとな
る。Alternatively, the electrical insulating materials 3a and 3b and the thermal stress relaxation materials 4a and 4b disposed inside the electrical insulating materials 3a and 3b may be omitted, and the thermally conductive functionally graded materials 2a and 2b may be located outside. In this case, as shown in FIG. 4, 100% electric insulating material such as silicon nitride is disposed on both sides of the electrically insulating material portions 2d, and the gradient composition portion 2 in which the composition ratio changes inside each of them.
It is preferable to provide c and 2c, and a thermal stress relaxation material portion 2e in which the thermal stress relaxation material such as palladium or copper is 100% at the center because electric insulating materials come on both sides.
【００２５】更に、実施例の熱電変換素子用熱応力緩和
パッドは、電気絶縁の関係で一端側が電気絶縁材料１０
０％で、他端側が熱応力緩和材料１００％でそれぞれ構
成されているが、必ずしも両端をそれぞれ１００％とす
る必要はない。例えば、熱応力緩和材料として電気的絶
縁性を有するものを採用すれば、電気絶縁材料が１００
％となる部分を設けなくても充分に電気絶縁が達成され
る。Further, the thermal stress relaxation pad for a thermoelectric conversion element according to the embodiment has one end on the side of an electric insulating material 10 for electric insulation.
0% and the other end side is made of 100% thermal stress relaxation material, respectively, but it is not always necessary to make both ends 100%. For example, if a material having electrical insulation properties is adopted as the thermal stress relaxation material, the electrical insulation material becomes 100%.
%, Electrical insulation is sufficiently achieved.
【００２６】[0026]
【発明の効果】以上の説明から明らかなように、本発明
の熱電変換素子用熱応力緩和パッド及び熱電変換素子
は、電気絶縁材料と熱応力緩和材料の組成割合が徐々に
変化する傾斜機能材料で熱応力緩和パッドを形成してい
るため、パッドが傾斜機能材料という一つの部材で構成
でき、しかもこの傾斜機能材料内を伝わる熱による応力
は、特定部分に集中せず分散する。この結果、構造が簡
単となり、熱応力の緩和力が高く、しかも寿命が長い熱
電変換素子用熱応力緩和パッド及び熱電変換素子とする
ことができる。As is clear from the above description, the thermal stress relaxation pad for a thermoelectric conversion element and the thermoelectric conversion element of the present invention are characterized by a functionally graded material in which the composition ratio of the electrically insulating material and the thermal stress relaxation material gradually changes. Since the thermal stress relaxation pad is formed by the above method, the pad can be constituted by one member of the functionally gradient material, and the stress due to the heat transmitted through the functionally gradient material is dispersed without being concentrated on a specific portion. As a result, the structure can be simplified, and the thermal stress relaxation pad for a thermoelectric conversion element and the thermoelectric conversion element having a long life can be obtained.
【００２７】加えて、熱応力緩和材料として、熱伝導率
が大きく弾性定数の小さいパラジウムまたは銅を使用
し、電気絶縁材料として、熱伝導性が良く、熱に対して
の変形が少なくしかも電気絶縁性が優れている窒化珪素
を使用しているので、発電効率の高い熱電変換素子とす
ることができる。In addition, palladium or copper having a large thermal conductivity and a small elastic constant is used as the thermal stress relaxation material, and the thermal insulating material has good thermal conductivity, is less deformed by heat, and is electrically insulating. Since silicon nitride having excellent properties is used, a thermoelectric conversion element having high power generation efficiency can be obtained.
【００２８】更に、加熱ダクト側の熱応力緩和材料とし
てパラジウムを、冷却ダクト側の熱応力緩和材料として
銅を使用しているので、宇宙用原子炉等高温側の使用温
度が銅の融点を超えるものにおいて、熱応力の緩和や寿
命の点で優れた熱電変換素子とすることができる。Further, since palladium is used as the thermal stress relaxing material on the heating duct side and copper is used as the thermal stress relaxing material on the cooling duct side, the operating temperature on the high temperature side such as a space reactor exceeds the melting point of copper. In this case, a thermoelectric conversion element excellent in terms of relaxation of thermal stress and life can be obtained.
【図１】本発明の熱電変換素子の実施例の断面図であ
る。FIG. 1 is a sectional view of an embodiment of a thermoelectric conversion element of the present invention.
【図２】本発明の熱電変換素子用熱応力緩和パッドの熱
応力分布を示す図である。FIG. 2 is a view showing a thermal stress distribution of a thermal stress relaxation pad for a thermoelectric conversion element of the present invention.
【図３】パラジウム材と窒化珪素材を接合したときの熱
応力分布を示す図である。FIG. 3 is a diagram showing a thermal stress distribution when a palladium material and a silicon nitride material are joined.
【図４】熱電変換素子用熱応力緩和パッドの他の実施例
の構造図である。FIG. 4 is a structural diagram of another embodiment of a thermal stress relaxation pad for a thermoelectric conversion element.
【図５】従来の熱電変換素子の断面図である。FIG. 5 is a cross-sectional view of a conventional thermoelectric conversion element.
１ 熱電素子 ２ａ，２ｂ 傾斜機能材料 ２ｃ 傾斜組成部 ２ｄ 電気絶縁材料部 ２ｅ 熱応力緩和材料部 ５ａ，５ｂ 電極 １０ 熱電変換素子 DESCRIPTION OF SYMBOLS 1 Thermoelectric element 2a, 2b Functionally graded material 2c Gradient composition part 2d Electrical insulating material part 2e Thermal stress relaxation material part 5a, 5b Electrode 10 Thermoelectric conversion element
Claims (6)
を徐々に変化させた熱伝導性の傾斜機能材料からなる熱
電変換素子用熱応力緩和パッド。1. A thermal stress relaxation pad for a thermoelectric conversion element comprising a thermally conductive functionally graded material in which the composition ratio of an electrically insulating material and a thermal stress relaxation material is gradually changed.
熱応力緩和材料としてパラジウムまたは銅を使用したこ
とを特徴とする請求項１記載の熱電変換素子用熱応力緩
和パッド。2. The thermal stress relaxation pad for a thermoelectric conversion element according to claim 1, wherein silicon nitride is used as said electrical insulating material, and palladium or copper is used as said thermal stress relaxing material.
材料と熱応力緩和材料の組成割合を徐々に変化させた熱
伝導性の傾斜機能材料を挟んだことを特徴とする熱電変
換素子。3. A thermoelectric conversion material characterized in that a thermally conductive functionally graded material in which a composition ratio of an electric insulating material and a thermal stress relaxation material is gradually changed is sandwiched between an electrode of a thermoelectric element and a heat source. element.
され、両ダクトからの熱応力を緩和する熱応力緩和パッ
ドを有する熱電変換素子において、前記熱応力緩和パッ
ドを電気絶縁材料と熱応力緩和材料の組成割合を徐々に
変化させた熱伝導性の傾斜機能材料で構成したことを特
徴とする熱電変換素子。4. A thermoelectric conversion element which is used between a heating duct and a cooling duct and has a thermal stress relaxation pad for relieving thermal stress from both ducts, wherein the thermal stress relaxation pad is connected to an electrically insulating material and a thermal stress. A thermoelectric conversion element comprising a thermally conductive functionally graded material in which a composition ratio of a relaxation material is gradually changed.
熱応力緩和材料としてパラジウムまたは銅を使用したこ
とを特徴とする請求項３または４記載の熱電変換素子。5. The thermoelectric conversion element according to claim 3, wherein silicon nitride is used as said electrical insulating material, and palladium or copper is used as said thermal stress relaxing material.
ジウムを、冷却ダクト側の熱応力緩和材料として銅を使
用したことを特徴とする請求項４記載の熱電変換素子。6. The thermoelectric conversion element according to claim 4, wherein palladium is used as the thermal stress relaxing material on the heating duct side and copper is used as the thermal stress relaxing material on the cooling duct side.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6339917A JP3056047B2 (en) | 1994-12-29 | 1994-12-29 | Thermal stress relaxation pad for thermoelectric conversion element and thermoelectric conversion element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6339917A JP3056047B2 (en) | 1994-12-29 | 1994-12-29 | Thermal stress relaxation pad for thermoelectric conversion element and thermoelectric conversion element |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08186295A JPH08186295A (en) | 1996-07-16 |
| JP3056047B2 true JP3056047B2 (en) | 2000-06-26 |
Family
ID=18331993
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6339917A Expired - Fee Related JP3056047B2 (en) | 1994-12-29 | 1994-12-29 | Thermal stress relaxation pad for thermoelectric conversion element and thermoelectric conversion element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3056047B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH10243670A (en) * | 1997-02-24 | 1998-09-11 | Central Res Inst Of Electric Power Ind | Thermoelectric transducing system |
| US20060005873A1 (en) * | 2004-07-06 | 2006-01-12 | Mitsuru Kambe | Thermoelectric conversion module |
| JP4810652B2 (en) * | 2004-10-18 | 2011-11-09 | 国立大学法人山口大学 | Thermoelectric conversion module |
-
1994
- 1994-12-29 JP JP6339917A patent/JP3056047B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH08186295A (en) | 1996-07-16 |
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