JP2004296959A

JP2004296959A - Thermoelectric element performance evaluating device and method for evaluating performance of thermoelectric element

Info

Publication number: JP2004296959A
Application number: JP2003089588A
Authority: JP
Inventors: Atsushi Murakami; 淳村上; Shigeru Watanabe; 滋渡辺
Original assignee: Citizen Watch Co Ltd
Current assignee: Citizen Watch Co Ltd
Priority date: 2003-03-28
Filing date: 2003-03-28
Publication date: 2004-10-21
Anticipated expiration: 2023-03-28
Also published as: JP4234475B2

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that it is impossible that a thermoelectric element is weighted and closely adhered to a temperature adjusting means, while an accurate maximum temperature difference is actually measured under conditions that an endothermic amount is zero. <P>SOLUTION: There are provided the temperature adjusting means, a heat flow measuring means, a heat flow control means, a weighting means and the thermoelectric element to be evaluated. A hot contact point of the thermoelectric element to be evaluated is connected to the temperature adjusting means so as to enable a thermal conduction, a cold contact point of the thermoelectric element to be evaluated is connected to one of the heat flow measuring means so as to enable the thermal conduction, the other of the heat flow measuring means is connected to the heat flow control means so as to enable the thermal conduction, the thermoelectric element to be evaluated is pressed to the temperature adjusting means at a constant weighting by the weighting means, and a heat flow of the heat flow measuring means is controlled to be zero by the heat flow control means. Thus, the accurate maximum temperature difference is actually measured under conditions that the endothermic amount is zero. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、ゼーベック効果を利用した熱電発電装置に用いる熱電素子、あるいはペルチェ効果を利用した熱電冷却装置に用いるペルチェ素子に関し、特に熱電素子あるいはペルチェ素子の性能評価装置の構造および評価方法に関する。
【０００２】
【従来の技術】
熱電素子は、熱エネルギーを電気エネルギーに、また電気エネルギーを熱エネルぎーに直接変換することができるデバイスである。
【０００３】
一般的な熱電素子の構造は、ほぼ同じ長さで柱状のｐ型熱電半導体およびｎ型熱電半導体の両端部で対にして熱電対を作り、その熱電対を複数個平面的に並べて、ｐ型熱電半導体とｎ型熱電半導体が交互に規則的になるように配置し、その熱電対を電気的に直列に接続する構造を有する。
【０００４】
熱電素子の両端の間に温度差を与えると、ゼーベック効果により電圧を発生する。また、熱電素子に直流電流を流すと、ペルチェ効果により一端で吸熱し、他端で放熱（発熱）する。
【０００５】
熱電素子はこのような可逆の効果を併せ持つデバイスであり、熱エネルギーと電気エネルギーの変換素子として様々な装置に応用されている。
【０００６】
熱電素子のゼーベック効果を利用することにより、熱エネルギーを電気エネルギーに直接変換することができるため、廃熱を利用して発電するような熱電発電装置は、熱エネルギーの有効な利用方法として注目をあびている。
【０００７】
また、熱電素子のペルチェ効果を利用することにより、熱電素子の吸熱する側に適当な熱源を熱伝導良好な状態で接続させれば、その熱源を冷やす熱電冷却装置として利用することができる。
【０００８】
また、熱電素子に流す電流を調節することにより、単に冷却するだけでなく、一定の温度に保つような温度調節装置としても利用することができる。
【０００９】
特に熱電冷却装置など、ペルチェ効果を利用した熱電素子のことを、その効果の名前からペルチェ素子と呼ぶこともあるが、本発明の説明においては、熱電素子と表記することにする。
【００１０】
上記熱電冷却装置は他の方式の冷却装置と異なり、コンプレッサーなどの機械部品を含まず、かつ小型化も可能なことから持ち運び可能なポータブル冷蔵庫や、集積回路やレーザー光源などの熱源に対する局所的な冷却装置または温度調節装置として利用されている。特に、光通信分野やＤＶＤピックアップなどに使われているレーザーダイオードは、高温になると壊れたり、性能が著しく劣化したりするため、特に光通信分野ではレーザーダイオードの冷却および一定温度に制御する温度調節は必須な技術であり、現在、熱電素子はこのような光通信分野において、一般的に利用されている。
【００１１】
ここで、熱電素子の従来の性能評価方法について説明する。熱電素子の熱電対を形成する一端である温接点を一定温度に保ち、冷接点から流入する熱量（吸熱量）をゼロに保つ状態で、直流電流を流し、その電流を徐々に大きくしていくと、熱電素子の熱電対を形成する他端である冷接点で吸熱し、温接点で放熱（発熱）し、温接点は一定温度に保たれ、冷接点は徐々に温度が下がり、両端の間の温度差が徐々に大きくなる。この効果をペルチェ効果という。
【００１２】
そして、ある電流で温度差が最大となり、それ以上電流を大きくすると温度差は徐々に小さくなる。この最大となった温度差を最大温度差という。この最大温度差は、熱電素子の性能を表す性能指数Ｚに比例することから、最大温度差は熱電素子の性能を表す指標となる。
【００１３】
また、熱電素子の温接点と冷接点の両端の温度差をゼロに保つようにして、電流を徐々に大きくした場合、冷接点から流入する熱量（吸熱量）は徐々に大きくなり、ある電流で最大となる。この熱量を最大吸熱量といい、上記の最大温度差と同様にこの最大吸熱量も熱電素子の性能を表す指標となる。
【００１４】
性能指数Ｚとは熱電素子の材料のゼーベック係数の２乗を熱電素子の材料の比抵抗と熱伝導率の各々で割ったもので、熱電素子の性能を表すのに最も重要な値である。しかし、この性能指数Ｚは熱電材料単体では測定することが可能であるが、熱電材料を加工して熱電素子に組み上げた場合には、直接測定することはとても困難である。
【００１５】
そして、熱電素子を組み上げる工程で、熱電材料のゼーベック係数や比抵抗や熱伝導率などが変わること、およびその他の要因なども含めて、熱電材料単体の性能指数Ｚから予想できる熱電素子の性能と、実際に作成した熱電素子の性能が異なることがしばしばある。そのため、熱電素子の実際の評価では最大温度差および最大吸熱量によって性能を判断する。
【００１６】
特に、最大温度差が分かれば、Ｚを逆算することができ、最大吸熱量もある程度の仮定による誤差は含まれるが計算することはできる。すなわち、最大温度差が分かれば、熱電素子の熱電性能が高いか低いか、すなわちゼーベック効果およびペルチェ効果の熱電性能が優れているかどうかを判断できる。
【００１７】
そのため、作成した熱電素子の性能評価は、通常最大温度差を測定することによって行う。
【００１８】
ここで、従来の熱電素子の最大温度差を測定する方法の例として、非特許文献１に開示された方法がある。この従来技術について図１１を用いて説明する。
【００１９】
まず、図１１に示すように温度調節装置１１４の上部に、性能を測定したいサンプルである評価対象熱電素子１０１を熱伝導性グリスを介して密着させる。
【００２０】
次に、断熱性材料からなる断熱部材１１０１を評価対象熱電素子１０１の上部に密着させ、加重部材１１０２を断熱部材１１０１の上に置く。
【００２１】
ここで、温度調節装置１１４は土台板１１３の上に固定されており、土台板１１３から垂直に上方に立てられた支持柱１１２とスライド部材１１０と固定部材１１１によって加重部材１１０２は上下に動くことができる。
【００２２】
加重部材１１０２は弾性変形可能な材料からなっており、断熱部材１１０１を下方に一定の力で押すことにより、評価対象熱電素子１０１を温度調節装置１１４に一定の加重を加えて密着させる。
【００２３】
温度調節装置１１４は、温度測定板１０３と温度調節熱電素子１０４と熱交換器１０６から成っている。
【００２４】
温度測定板１０３には評価対象熱電素子１０１と接する面近傍に温度センサーが埋め込まれており、評価対象熱電素子１０１の温接点の温度を測定し、その温度が一定になるように温度調節熱電素子１０４の電流を制御している。
【００２５】
また、断熱部材１１０１にも評価対象熱電素子１０１と接する面近傍に温度センサーが埋め込まれており、評価対象熱電素子１０１の冷接点の温度を測定している。
【００２６】
このようにセッティングされた状態で評価対象熱電素子１０１に電流を流して、評価対象熱電素子１０１の温接点と冷接点の両端に生じる温度差を測定する。
【００２７】
ここで、評価対象熱電素子１０１と温度調節装置１１４（温度測定板１０３）との接触面に熱伝導性グリスを介して一定の加重を加えるのは、評価対象熱電素子１０１の温接点を精密に一定温度に制御するために、評価対象熱電素子１０１と温度調節装置１１４（温度測定板１０３）との間の熱抵抗をできるだけ小さくし、かつ熱抵抗のばらつきを少なくする必要があるからである。
【００２８】
つまり、評価対象熱電素子１０１の温接点では、評価対象熱電素子１０１に流した電流で生じるジュール熱（電力）分の熱が温度調節装置１１４に流れ込むために、その間の熱抵抗が大きくなったり、ばらついたりすることによって、接触面を通過する熱（単位：Ｗ）と、接触面の熱抵抗（単位：℃／Ｗ）とを掛け合わせた温度差分だけ温接点の温度に測定誤差が生じてしまう。
【００２９】
面と面との接触部分において、熱伝導を良好に保つために熱伝導性グリスなどで面と面を密着させ、ある程度以上の加重をかけることにより、接触部分の熱抵抗を小さくできることは一般に知られている。
例えば、接触面では熱伝導性グリスを介して１０（ｋｇｆ／ｃｍ^２）以上の垂直な加重で密着させた場合の熱抵抗率は１ｃｍ℃／Ｗである、というように文献によって熱抵抗値が判明しているため、その接触面による温度差のロス分を正しく見積もることができる。もし、一定の加重で密着させない場合は接触面の熱抵抗を正しく見積もることができない。
そのために、一定の加重を加えて、熱抵抗をできるだけ小さく、かつ一定になるようにすることは熱電素子の評価をする上で必要不可欠である。
【００３０】
【非特許文献１】
シドレンコ（Ｓｉｄｏｒｅｎｋｏ），「熱伝素子の動的変形の実験的研究へのレーザドップラー流速計の応用（ＡＰＰＬＩＣＡＴＩＯＮＯＦＬＡＳＥＲＤＯＰＰＬＥＲＡＮＥＭＯＭＥＴＲＹＦＯＲＥＸＰＥＲＩＭＥＮＴＡＬＩＮＶＥＳＴＩＧＡＴＩＯＮＯＦＴＨＥＲＭＯＥＬＥＣＴＲＩＣＥＬＥＭＥＮＴＳＤＹＮＡＭＩＣＤＥＦＯＲＭＡＴＩＯＮ）」，第１４回国際熱電学会会報（ＰｒｏｃｅｅｄｉｎｇｓｏｆｔｈｅＸＩＶＩｎｔｅｒｎａｔｉｏｎａｌＣｏｎｆｅｒｅｎｃｅｏｎＴｈｅｒｍｏｅｌｅｃｔｒｉｃｓ），ロシア，物理技術研究所（Ｐｈｙｓｉｃａｌ−ＴｅｃｈｎｉｃａｌＩｎｓｔｉｔｕｔｅ），平成７年６月２７日，ｐ．３６６
【００３１】
【発明が解決しようとする課題】
しかしながら、温接点の熱抵抗を小さく一定にして温度差の測定精度を上げるために加重を加えるとき、上記のように従来技術では断熱部材および加重部材によって加重を加える方法で性能評価を行っている。ここで、断熱部材は断熱性材料からなるものであるが、当然ながら熱伝導率はゼロではなく、ある程度は熱を通してしまう。
【００３２】
そのため、この状態で最大温度差を測定すると、冷接点では断熱部材を通して外部から熱が流入してしまい、測定している冷接点はその熱の流入分だけ暖められてしまい、冷接点の温度が上昇してしまうため、測定された温度差は本来の最大温度差よりも小さくなってしまう。
【００３３】
すなわち、外部からの熱の流入によって本来の最大温度差を正確に測定することができないという問題があった。
【００３４】
そのため、従来の熱電素子の評価方法では正確な最大温度差を実際に測定することは不可能であった。このため、理論的な計算による最大温度差は予想できるが、実際に測定することによる熱電素子の品質の確認は非常に難しいという問題があった。
【００３５】
特に、小型の熱電素子の場合は加重をかけるために接する断熱部材の影響が顕著になるため測定誤差はより大きくなる傾向にある。
【００３６】
〔発明の目的〕
そこで、本発明の目的は上記の問題を解決して、熱電素子に加重を加えて、接触部分の熱抵抗を小さく一定にし、しかも熱電素子の冷接点における外部からの熱の流入をゼロにすることで、正確な最大温度差を測定することのできる熱電素子性能評価装置の構造およびその評価方法を提供することにある。
【００３７】
【課題を解決するための手段】
上記の課題を解決するために、本発明の熱電素子性能評価装置および熱電素子の性能評価方法においては、下記に記載する構成を採用する。
【００３８】
すなわち、本発明の熱電素子性能評価装置は、温度調節手段と、熱流測定手段と、熱流制御手段と、加重手段と、評価対象熱電素子を備え、評価対象熱電素子の温接点と温度調節手段とを熱伝導可能に接続し、評価対象熱電素子の冷接点と熱流測定手段の一方とを熱伝導可能に接続し、熱流測定手段の他方と熱流制御手段とを熱伝導可能に接続し、加重手段によって評価対象熱電素子と温度調節手段との接続部分に一定の加重が加わることを特徴とする。
調節手段との接続部分に一定の加重を与える熱電素子性能評価装置。
また、熱流測定手段が、評価対象熱電素子と同じ断面形状であることが好ましい。
また、熱流測定手段が、一様な熱伝導率の材質で一様な断面形状であり、断面のほぼ中央部で熱流が流れる方向に平行な線上の少なくとも２点以上の温度を測ることが好ましい。
また、熱流測定手段が、熱電素子と温度測定板とを有することがさらに好ましい。
また、評価対象熱電素子および熱流測定手段とが真空雰囲気内にあることがなおよい。
さらに、評価対象熱電素子と熱流測定手段との間に薄板状のヒーターを有することが望ましい。
また、本発明の熱電素子の性能評価方法は、温度調節手段によって評価対象熱電素子の温接点の温度を一定に保ち、熱流制御手段によって熱流測定手段の熱流をゼロに制御し、評価対象熱電素子の温接点および冷接点の２つの温度を測定することを特徴とする。
【００３９】
〔作用〕
本発明の熱電素子性能評価装置では、評価対象熱電素子に熱流測定手段を接続し、熱流測定手段を熱流制御手段に接続し、加重手段で評価対象熱電素子を温度調節手段に対して一定加重で押し付け、熱流制御手段によって熱流測定手段の熱流をゼロに制御することによって、評価対象熱電素子の温接点と温度調節手段との接触面の熱抵抗が小さく一定になり、かつ評価対象熱電素子の冷接点での外部からの熱の流入をゼロにすることができる。そのため、評価対象熱電素子の吸熱量がゼロである理想的な状態で正確な最大温度差を測定することができる。その結果、熱電素子の品質を実際に測定することによって確認することができるようになり、評価通りの性能の熱電素子をユーザーに提供することができる。
【００４０】
【発明の実施の形態】
以下、本発明の熱電素子性能評価装置の構成における最適な実施形態について図面を用いて説明する。
【００４１】
（第１の実施の形態）
図１〜図７を用いて本発明の第１の実施の形態における熱電素子性能評価装置の構造および評価方法について説明する。
【００４２】
図１は本発明の熱電素子性能評価装置の全体的な構成を示す構造図である。まず、土台板１１３の上部に温度調節装置１１４が固定されており、温度調節装置１１４の上部に性能を測定したいサンプルである評価対象熱電素子１０１の温接点を熱伝導性グリスを介して密着させる。
【００４３】
温度調節装置１１４は、具体的には温度測定板１０３と温度調節熱電素子１０４と熱交換器１０６から成っており、評価対象熱電素子１０１は温度測定板１０３に密着している。
【００４４】
温度測定板１０３は評価対象熱電素子１０１の温接点の温度を測定し、その温度が設定温度で一定になるように温度調節熱電素子１０４の電流を制御する。
【００４５】
そして、熱流制御装置１１５の下部に熱流測定器１０２を熱伝導良く接合し、評価対象熱電素子１０１の冷接点と熱流測定器１０２の下部を熱伝導良く密着させる。
【００４６】
熱流制御装置１１５は、具体的には熱流制御熱電素子１０５と熱交換器１０７とから成っており、熱流制御熱電素子１０５は熱流測定器１０２に熱伝導良く接合している。
【００４７】
さらに、熱流制御装置１１５と可動板１０９とは、弾性を有する加重バネ１０８を介して接合されており、可動板１０９はスライド部材１１０に接合されている。
【００４８】
ここで、温度調節装置１１４は土台板１１３の上に固定されており、土台板１１３から垂直に上方に立てられた支持柱１１２とスライド部材１１０と固定部材１１１によって、可動板１０９は上下に動くことができる。
【００４９】
可動板１０９が上下に動くことにより、可動板１０９と共に加重バネ１０８、熱流制御装置１１５は上下に動く。ここで、加重バネが一定距離縮むまで可動板１０９を押し下げることにより、熱流制御装置１１５、熱流測定器１０２、評価対象熱電素子１０１、温度調節装置１１４は上下方向に加重され、評価対象熱電素子１０１は温度調節装置１１４に一定の加重が加わり密着される。
【００５０】
そして、上記で説明した構造部材全ては真空チャンバー１１６内に入っており、上記で説明した構造部材をセッティングしたあとで、真空に引く。
【００５１】
ここで、本発明の特徴的な構造として、評価対象熱電素子１０１の温接点は温度調節装置１１４に一定の加重で密着しており、かつ評価対象熱電素子１０１の冷接点は熱流測定器１０２に密着している。
【００５２】
そして、熱流測定器１０２によって評価対象熱電素子１０１の冷接点に流入する熱流を測定し、同時に評価対象熱電素子１０１の冷接点の温度を測定し、さらに、熱流制御装置１１５によって熱流測定器１０２で測定した熱流をゼロにするように熱流制御熱電素子１０５の電流を制御する。
【００５３】
このようにセッティングされた状態で、評価対象熱電素子１０１に電流を流して、評価対象熱電素子１０１の温接点と冷接点の両端に生じる最大温度差を測定することによって、評価対象熱電素子１０１の冷接点から流入する熱流をゼロにした状態での正確な最大温度差を測定することができる。
【００５４】
上記の測定を真空チャンバー１１６内で行うことによって、評価対象熱電素子１０１の冷接点が結露することを防ぎ、さらに評価対象熱電素子１０１の温接点と冷接点の間の側面から出入りする熱を断熱することができるため、より最大温度差の測定精度が増す特徴を持っている。
【００５５】
図２は本発明の熱電素子性能評価装置における評価対象熱電素子１０１、温度調節熱電素子１０４、および熱流制御熱電素子１０５の代表的な構造を表した断面図である。ｐ型熱電半導体２０１とｎ型熱電半導体２０２を、交互に規則的になるように配置し、各々の熱電半導体の両端部分で配線電極２０３により配線し、複数のｐ型熱電半導体とｎ型熱電半導体が、交互に電気的に直列になるように接続する。
【００５６】
そして、直列に接続した両端の熱電半導体には電流を流すためのリード線をつなげる２つの引き出し電極２０４がそれぞれ接続されている。
また、配線電極２０３、引き出し電極２０４と熱伝導板２０５、２０６とはそれぞれ接合されており、一方が温接点、他方が冷接点となっている。電流を流す向きでどちらも温接点または冷接点になり得る。
【００５７】
熱電素子は、例えば図２で熱伝導板２０５側を冷接点となるように電流を流し、冷却する場合、冷接点で吸熱した熱量と熱電素子に流す電流によって生じるジュール熱を温接点となる熱伝導板２０６側に運ぶ。そのため、熱伝導板２０６側ではその熱を放熱可能な構造にしないと熱がたまって温度が上昇してしまう。そして、その影響で冷接点側の温度も上昇してしまう。
【００５８】
また熱伝導板２０５側を温接点になるようにして加熱する場合、つまりは逆に電流を流した場合は、熱伝導板２０６側が冷接点となり、熱伝導板２０６側で必要な熱を与える構造にて温度を保たないと、温度がさがってしまい、その影響で加熱したい熱伝導板２０５側の温度も下がってしまう。
【００５９】
つまり、熱電素子の一方を冷却したり、加熱したり、温度調節したりするためには、他方で十分に熱交換できるヒートシンクのようなものが必要不可欠である。
【００６０】
そのため、図１において、温度調節熱電素子１０４に熱交換器１０６を接合し、熱流制御熱電素子１０５に熱交換器１０７を接合している。
【００６１】
熱伝導板２０５，２０６としては、窒化アルミニウムやアルミナなどの熱伝導の良いセラミックスを用いる。
【００６２】
熱電材料としては、ｐ型熱電半導体２０１にはＢｉＴｅＳｂからなる合金を用い、またｎ型熱電半導体２０２にはＢｉＴｅＳｅからなる合金を用いている。しかし、熱電材料としてはこれに制限されるものではなく、他のＢｉＴｅ系、ＦｅＳｉ系など用途に応じて様々な熱電材料を用いることができる。
【００６３】
図３は温度調節装置１１４の斜視図である。熱交換器１０６の上部に温度調節熱電素子１０４を熱伝導良く接合し、温度調節熱電素子１０４の上部に温度測定板１０３を熱伝導良く接合する。
【００６４】
上記各構造部材の接合は、熱伝導性接着剤で固定するか、または熱伝導性グリスで密着させてビス止めなどで固定する。
【００６５】
温度測定板１０３は、評価対象熱電素子１０１と接する面近傍にサーミスターまたは白金測温抵抗体などの温度センサー３０１を埋め込み、評価対象熱電素子１０１の温接点の温度を測定し、温度センサー３０１の信号をフィードバックして、評価対象熱電素子１０１の温接点の温度が一定温度を保つように、温度調節熱電素子１０４に電流を投入するリード線３０２に流す電流を制御する。
【００６６】
温度調節熱電素子１０４の構造は、図２に示した一般的な熱電素子の構造と同じであり、評価対象熱電素子１０１よりもかなり大きい熱電素子を用いる。
【００６７】
熱交換器１０６は、密閉された空洞の内部を有し、その内部に水などの熱を運ぶことのできる液体を満たし、液体を外部から出し入れする循環路３０３を有し、外部でその液体の温度を一定に保つように循環させる。
【００６８】
このようにして、温度調節熱電素子１０４の温接点を介して熱交換器１０６に出入りする熱を外部に出し入れすることができ、評価対象熱電素子１０１の温接点の温度を精密に制御することができる。
【００６９】
このようなシステムの具体的な例としては、日本ブロアー（株）のＳＬ−１０ＷとＳＬ−ＣＰ１２０６の組み合わせなどが挙げられる。
【００７０】
熱交換器１０６は真空チャンバー１１６内に入れる構造上、構成しやすい水循環型としたが、真空チャンバー１１６の壁面に熱交換器１０６を設ける構造とすれば、フィンなど外気と熱交換する部分を真空チャンバー外に出すことができるため、空冷型でも可能となる。
【００７１】
図４は可動板１０９、加重バネ１０８、熱流制御装置１１５、および熱流測定器１０２の斜視図である。
【００７２】
図４に示すように、可動板１０９の下部に加重バネ１０８を接合し、加重バネ１０８の下部に熱熱交換器１０７を接合し、熱交換器１０７の下部に熱流制御熱電素子１０５を熱伝導良く接合し、熱流制御熱電素子１０５の下部に熱流測定器１０２を熱伝導良く接合する。
【００７３】
上記各構造部材の接合は、熱伝導性接着剤で固定するか、または熱伝導性グリスで密着させてビス止めなどで固定する。
【００７４】
図５は熱流測定器１０２の斜視図である。熱流測定器１０２は、一様な熱伝導率を有する材料からなっており、評価対象熱電素子１０１と同じ断面形状を持ち、その断面形状の中央部分で、かつ評価対象熱電素子１０１の冷接点と接する面近傍と熱流制御熱電素子１０５と接する面近傍とにサーミスターまたは白金測温抵抗体などの２つの温度センサー５０１、５０２を埋め込み、温度センサー５０１で評価対象熱電素子１０１の冷接点の温度を測定し、同時に温度センサー５０２で熱流制御熱電素子１０５と接する面近傍の温度を測定する。
【００７５】
そして、温度センサー５０１、５０２の信号をフィードバックして、温度センサー５０１、５０２の２つの温度が同じ温度になるように、熱流制御熱電素子１０５に電流を投入するリード線４０１に流す電流を制御する。
【００７６】
一般的な伝熱理論において、熱伝導率が一様であり、かつ断面形状が一様な部材の断面と垂直な方向に、ある距離離れた２点の温度が同じ場合、その断面を通過する熱流はゼロとなる。
【００７７】
したがって、上記のように温度センサー５０１、５０２の温度が同じ場合、熱流測定器を上下方向に移動する熱流はゼロとなる。
【００７８】
このとき、評価対象熱電素子１０１と熱流測定器１０２の断面形状が同じであれば、熱流が直線的に、かつ一様になるため、熱流測定の感度が向上する効果がある。
【００７９】
熱流制御熱電素子１０５の構造は、図２に示した一般的な熱電素子の構造と同じであり、温度調節熱電素子１０４と同様に評価対象熱電素子１０１よりもかなり大きい熱電素子を用いる。また、熱交換器１０７の構造も熱交換器１０６と同じ構造である。
【００８０】
そして、可動板１０９はスライド部材に接合されており、上下に水平に動かすことができ、可動板１０９と熱交換器１０７（熱流制御装置１１５）とは、平面的に配置した複数の同じ加重バネ１０８でつながっている。そのため、評価対象熱電素子１０１を温度測定板１０３と熱流測定器１０２とで挟み込んで密着させるときに、それぞれの接触面の平行度のバラツキを加重バネ１０８で吸収することができ、熱伝導良く密着させることができる。
【００８１】
また、加重バネ１０８の縮む長さを調節することで、加重量を任意に調節することが可能となる。
【００８２】
上記構造をとることにより、熱流測定器１０２の熱流をゼロにして、同時に評価対象熱電素子１０１を温度測定板１０３に一定の加重で密着させることができる。
【００８３】
また、図４に示した熱流制御熱電素子１０５は１段であるが、大きさの異なる熱電素子を２つ重ねた構造にすることによって、１段目の熱電素子で大まかな温度制御を行い、２段目の熱電素子で細かな温度制御を行うことにより、制御範囲が広がり、さらに熱流制御（温度調節）の精度を向上させることができる。
【００８４】
さらに、熱流測定器１０２を通過する熱流と温度センサー５０１、５０２の温度差とは比例するため、熱伝導率が正確に判明している材料で熱流測定器１０２を構成することによって、温度センサー５０１、５０２で測定した温度から熱流を計算できる。
【００８５】
この場合、評価対象熱電素子１０１の温接点と冷接点の両端に生じる温度差は、上記熱流が流入した分だけ最大温度差より小さくなる。したがって、熱流をゼロに制御しなくても、計算値によって評価は可能である。
【００８６】
図６は温度調節装置１１４の制御システムを説明した図である。熱交換器１０６は真空チャンバー外の恒温水循環装置６０７につながっている。熱交換器１０６の内部は上記で説明したように恒温水を導入および排出する循環路３０３があり、温度調節熱電素子１０４からの熱の流入、流出に対して迅速に反応し、恒温を保つ。
【００８７】
温度測定板１０３は、温度センサー３０１の信号を温度に変換する温度変換回路６０１につながっている。温度変換回路６０１は、温度調節熱電素子１０４の電流を制御する電流制御回路６０２につながっている。電流制御回路６０２は電源回路６０３およびその先の外部コンセント６０４につながっている。電流制御回路６０２は、そのリアルタイムの温度と設定温度とを表示する表示部、設定を変更するスイッチ等が集まるコンソール６０５につながっている。そして１つの制御装置６０６が形成されている。
【００８８】
電流制御回路６０２では、温度センサー３０１で測定した温度が設定温度になるように、温度センサー３０１で測定した温度をフィードバック制御（例えばＰＩＤ制御など）によって温度調節熱電素子１０４に流す電流を制御する。このような制御方法によって精度的には設定温度±０．１℃程度が実現できる。
【００８９】
図７は熱流制御装置１１５の制御システムを説明した図である。熱交換器１０７、循環路４０２，恒温水循環装置７０７の構造は図６で説明した熱交換器６０７の周辺構造と同じである。
【００９０】
熱流測定器１０２は、温度センサー５０１、５０２の信号を温度に変換する温度変換回路７０１につながっている。温度変換回路７０１は、熱流制御熱電素子１０５の電流を制御する電流制御回路７０２につながっている。電流制御回路７０２は電源回路７０３およびその先の外部コンセント７０４につながっている。電流制御回路７０２は、そのリアルタイムの温度と温度差を表示する表示部、設定を変更するスイッチ等が集まるコンソール７０５につながっている。そして１つの制御装置７０６が形成されている。
【００９１】
電流制御回路７０２では、温度センサー５０１、５０２で測定した温度が同じ温度になるように、つまり温度センサー５０１、５０２の温度差がゼロになるように、温度センサー５０１、５０２で測定した温度をフィードバック制御（例えばＰＩＤ制御など）によって熱流制御熱電素子１０５に流す電流を制御する。
【００９２】
本発明の特徴として、上記の手段を用いることによって、熱流測定器１０２を通過する熱流をゼロにするように制御することが可能となり、評価対象熱電素子１０１の温接点を温度測定板１０３に一定の加重で密着させ、かつ評価対象熱電素子１０１の冷接点の熱の流入流出をゼロにすることができ、そのときの評価対象熱電素子１０１の温接点と冷接点の温度（温度差）を測定して、最大温度差を精度良く正確に測定することが可能となる。
【００９３】
（第２の実施の形態）
次に、図８を用いて、本発明の第２の実施の形態における熱電素子性能評価装置の構造および評価方法について説明する。
【００９４】
図８は、第１の実施の形態において図５で構造を説明した熱流測定器１０２の別の構造である。図８に示すように、熱流測定器１０２として熱流測定熱電素子８０１の一方と温度測定板８０４を熱伝導性接着剤などで熱伝導良く接合し、熱流測定熱電素子８０１の他方と熱流制御熱電素子１０５とを熱伝導良く接合する。
【００９５】
温度測定板８０３の熱流測定熱電素子８０１と接合していない面近傍には、サーミスターまたは白金測温抵抗体などの温度センサー８０４を埋め込み、評価対象熱電素子１０１に熱伝導良く密着させて、評価対象熱電素子１０１の冷接点の温度を測定する。
【００９６】
第２の実施の形態の構造的な特徴は、熱流測定器１０２が図８に示す構造におきかわるだけで、他の部材の構造は第１の実施の形態と同じである。
【００９７】
熱流測定熱電素子８０１を通過する熱流と、熱流測定熱電素子８０１の冷接点と温接点の温度差とは比例し、熱流測定熱電素子８０１の冷接点と温接点の温度差と熱流測定熱電素子８０１が発生する電圧とは比例する。つまり、熱流測定熱電素子８０１を通過する熱流と熱流測定熱電素子８０１が発生する電圧とは比例することになる。つまり、熱流測定熱電素子８０１が発生する電圧をゼロにするように熱流制御熱電素子１０５の電流を制御することによって、熱流測定熱電素子８０１を通過する熱流をゼロにすることが可能となる。
【００９８】
図９は、第２の実施の形態における熱流制御装置１１５の制御システムを説明した図である。
【００９９】
熱流測定器１０２は、熱流測定熱電素子８０１のリード線８０２によって、熱流制御熱電素子１０５の電流を制御する電流制御回路９０２につながっている。また、熱流測定器１０２は、温度測定板８０３の温度センサー８０４の信号を温度に変換する温度変換回路９０１につながっている。温度変換回路９０１は、電流制御回路９０２につながっている。電流制御回路９０２は電源回路７０３およびその先の外部コンセント７０４につながっている。電流制御回路９０２は、そのリアルタイムの温度と電圧を表示する表示部、設定を変更するスイッチ等が集まるコンソール９０３につながっている。
【０１００】
電流制御回路９０２では、熱流測定熱電素子８０１で測定した電圧がゼロになるように、つまり熱流測定熱電素子８０１の温接点と冷接点の温度差がゼロになるように、熱流測定熱電素子８０１で測定した電圧をフィードバック制御（例えばＰＩＤ制御など）によって熱流制御熱電素子１０５に流す電流を制御する。
【０１０１】
図５に示す構造の熱流測定器１０２は、熱流を測定するのにサーミスターや白金測温抵抗体などの温度センサー５０１、５０２を使っているため、温度センサーの検出部分以外の封止材料やコーティング材料などが持つ熱容量の分だけ、温度を検出する応答速度が若干遅くなる可能性がある。
【０１０２】
ところが、図８に示す構造の熱流測定器１０２は、熱流測定熱電素子８０１の熱電材料のみを熱流が流れ、かつ熱電材料自体が温度差検出部分であるために、応答速度を遅くする無駄な熱容量を持たない。そのため、図８に示す構造の熱流測定器１０２は、図５に示す構造の熱流測定器１０２に比較して、熱流に対する応答速度を速くすることができるため、より測定精度が高くなるメリットを持つ。
【０１０３】
また、一般的に熱電素子は、対数と温度差を掛け合わせた値と発生する電圧とが比例するため、熱流測定熱電素子８０１の対数を多くすればするほど、検出される電圧が大きくなるため、対数を多くすることにより熱流を検出する電圧の感度が上がり、測定精度を大きく向上させることができ、より正確な最大温度差の測定が可能となる。
【０１０４】
（第３の実施の形態）
次に、図１０を用いて、本発明の第３の実施の形態における熱電素子性能測定装置の構造および評価方法について説明する。
【０１０５】
図１０に示すように第３の実施の形態の構造的な特徴は評価対象熱電素子１０１と熱流測定器１０２との間にヒーター１００１を挿入したことである。ここで、上記の第１の実施の形態および第２の実施の形態で説明した同じ方法で、熱流測定器１０２を通過する熱流をゼロに制御しながら、ヒーター１００１の熱量を測定することによって、評価対象熱電素子１０１の最大温度差だけでなく、最大温度差から仮定計算によって見積もっていた最大吸熱量をも実際に測定することが可能となる。
【０１０６】
上記第１の実施の形態、第２の実施の形態および第３の実施の形態において、熱流測定器１０２の温度センサー５０１、５０２、８０４の導線、および熱流測定熱電素子８０１のリード線８０２を通して、わずかではあるが熱が出入りしてしまう可能性がある。評価対象熱電素子１０１、および熱流測定器１０２が小さいサイズになるとそのわずかな熱でも影響を受けるようになり、大きな誤差の原因となることもある。その対策として、図示はしないが、熱流制御熱電素子１０５に上記リード線を接触させる構造をとることにより、リード線を通して出入りする熱はゼロにすることができ、小さいサイズの熱電素子の評価も高精度で行うことができる。
【０１０７】
また、第１の実施の形態、第２の実施の形態および第３の実施の形態において２つの熱交換器１０６、１０７を用いているが、大きな熱交換器であれば１つで代用することも可能である。その場合、測定範囲を広げるために熱流制御熱電素子１０５を２段の熱電素子にすることによって測定の余裕度が向上する。
【０１０８】
【発明の効果】
以上の説明で明らかなように、本発明の熱電素子性能評価装置は、評価対象熱電素子に熱流測定手段を接続し、熱流測定手段を熱流制御手段に接続し、加重手段で評価対象熱電素子を温度調節手段に対して一定加重で押し付け、熱流制御手段によって熱流測定手段の熱流をゼロに制御することによって、評価対象熱電素子の温接点と温度調節手段との接触面の熱抵抗を小さく一定にすることができ、かつ評価対象熱電素子の冷接点での外部からの熱の流入をゼロにすることができる。そのため、評価対象熱電素子の吸熱量がゼロである理想的な状態で正確な最大温度差を測定することができる。
【０１０９】
また、熱電素子を熱流測定手段として用いることにより、熱流に対する応答速度を速くすることができるため、より測定精度が高くなるメリットを持つ。
【０１１０】
そして、熱流測定手段から外側へ出るリード線を熱流制御手段に接続することにより、リード線を伝わって出入りする熱を遮断することができ、小型の熱電素子においても正確に測定することができる。
【０１１１】
さらに、評価対象熱電素子と熱流測定手段の間にヒーターを設けることで、その熱量を測定することによって、評価対象熱電素子の最大温度差だけでなく、最大吸熱量をも実際に測定することが可能となる。
【０１１２】
その結果、熱電素子の品質を実際に測定することによって確認することができるようになり、評価通りの性能の熱電素子をユーザーに提供することができる。
【図面の簡単な説明】
【図１】本発明の第１の実施の形態における熱電素子性能評価装置の全体的な構成を示す構造図である。
【図２】本発明の第１の実施の形態における熱電素子性能評価装置の熱電素子の断面図である。
【図３】本発明の第１の実施の形態における熱電素子性能評価装置の温度調節装置の斜視図である。
【図４】本発明の第１の実施の形態における熱電素子性能評価装置の可動板、加重バネ、熱流制御装置、および熱流測定器の斜視図である。
【図５】本発明の第１の実施の形態における熱電素子性能評価装置の熱流測定器の斜視図である。
【図６】本発明の第１の実施の形態における熱電素子性能評価装置の温度調節装置の制御システム図である。
【図７】本発明の第１の実施の形態における熱電素子性能評価装置の熱流制御装置の制御システム図である。
【図８】本発明の第２の実施の形態における熱電素子性能評価装置の熱流測定器の別の構造図である。
【図９】本発明の第２の実施の形態における熱電素子性能評価装置の、熱流制御装置の制御システム図である。
【図１０】本発明の第３の実施の形態における熱電素子性能評価装置の全体的な構成を示す構造図である。
【図１１】従来の熱電素子性能評価装置の全体的な構成を示す構造図である。
【符号の説明】
１０１評価対象熱電素子
１０２熱流測定器
１０３、８０３温度測定板
１０４温度調節熱電素子
１０５熱流制御熱電素子
１０６、１０７熱交換器
１０８加重バネ
１０９可動板
１１０スライド部材
１１１固定部材
１１２支持柱
１１３土台板
１１４温度調節装置
１１５熱流制御装置
１１６真空チャンバー
２０１ｐ型熱電半導体
２０２ｎ型熱電半導体
２０３配線電極
２０４引き出し電極
２０５２０６熱伝導体
３０１、５０１，５０２，８０４温度センサー
３０２、４０１リード線
３０３、４０２循環路
６０１、７０１、９０１温度変換回路
６０２、７０２，９０２電流制御回路
６０３、７０３電源回路
６０４、７０４外部コンセント
６０５、７０５、９０３コンソール
６０６、７０６制御装置
６０７、７０７恒温水循環装置
１００１ヒーター
１１０１断熱部材
１１０２加重部材[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a thermoelectric element used for a thermoelectric generator using the Seebeck effect, or a Peltier element used for a thermoelectric cooler using the Peltier effect, and particularly to a structure and an evaluation method of a thermoelectric element or a performance evaluation device for a Peltier element.
[0002]
[Prior art]
A thermoelectric element is a device that can directly convert thermal energy to electrical energy and electrical energy to thermal energy.
[0003]
The structure of a general thermoelectric element is such that a pair of thermocouples are formed at both ends of a columnar p-type thermoelectric semiconductor and an n-type thermoelectric semiconductor having substantially the same length, and a plurality of the thermocouples are arranged in a plane to form a p-type thermocouple. It has a structure in which thermoelectric semiconductors and n-type thermoelectric semiconductors are arranged alternately and regularly, and the thermocouples are electrically connected in series.
[0004]
When a temperature difference is applied between both ends of the thermoelectric element, a voltage is generated by the Seebeck effect. When a direct current is applied to the thermoelectric element, heat is absorbed at one end by the Peltier effect and heat is released (heated) at the other end.
[0005]
The thermoelectric element is a device having such a reversible effect, and is applied to various devices as a conversion element between thermal energy and electric energy.
[0006]
By utilizing the Seebeck effect of thermoelectric elements, thermal energy can be directly converted into electrical energy.Therefore, thermoelectric generators that generate electricity using waste heat have attracted attention as an effective method of using thermal energy. I'm afraid.
[0007]
Further, if a suitable heat source is connected to the heat absorbing side of the thermoelectric element with good heat conduction by utilizing the Peltier effect of the thermoelectric element, the thermoelectric element can be used as a thermoelectric cooling device for cooling the heat source.
[0008]
Further, by adjusting the current flowing through the thermoelectric element, it can be used not only for cooling but also as a temperature adjusting device for maintaining a constant temperature.
[0009]
In particular, a thermoelectric element utilizing the Peltier effect, such as a thermoelectric cooling device, may be referred to as a Peltier element from the name of the effect, but will be referred to as a thermoelectric element in the description of the present invention.
[0010]
Unlike other types of cooling devices, the thermoelectric cooling device does not include mechanical parts such as a compressor, and can be miniaturized, so that it can be carried around, and can be carried around in a portable refrigerator or a local heat source such as an integrated circuit or a laser light source. It is used as a cooling device or a temperature control device. In particular, laser diodes used in the optical communication field and DVD pickups can be broken or their performance degraded significantly at high temperatures. Is an indispensable technology, and at present, thermoelectric elements are generally used in such an optical communication field.
[0011]
Here, a conventional performance evaluation method of a thermoelectric element will be described. A DC current is applied and the current is gradually increased while keeping the hot junction, which is one end of the thermocouple of the thermoelectric element, at a constant temperature and keeping the amount of heat (heat absorption) from the cold junction at zero. And the cold junction at the other end, which forms the thermocouple of the thermoelectric element, absorbs heat, radiates heat at the hot junction (heats), the hot junction is kept at a constant temperature, the cold junction gradually decreases in temperature, and Temperature difference gradually increases. This effect is called the Peltier effect.
[0012]
Then, the temperature difference becomes maximum at a certain current, and when the current is further increased, the temperature difference gradually decreases. This maximum temperature difference is called the maximum temperature difference. Since the maximum temperature difference is proportional to the performance index Z indicating the performance of the thermoelectric element, the maximum temperature difference is an index indicating the performance of the thermoelectric element.
[0013]
If the current is gradually increased by keeping the temperature difference between both ends of the hot junction and the cold junction of the thermoelectric element at zero, the amount of heat (heat absorption) flowing from the cold junction gradually increases. Will be the largest. This heat amount is called a maximum heat absorption amount, and like the above-described maximum temperature difference, this maximum heat absorption amount is also an index indicating the performance of the thermoelectric element.
[0014]
The figure of merit Z is obtained by dividing the square of the Seebeck coefficient of the material of the thermoelectric element by each of the specific resistance and the thermal conductivity of the material of the thermoelectric element, and is the most important value for expressing the performance of the thermoelectric element. However, this figure of merit Z can be measured with a single thermoelectric material, but it is very difficult to directly measure the thermoelectric material when the thermoelectric material is processed and assembled into a thermoelectric element.
[0015]
Then, in the process of assembling the thermoelectric element, the Seebeck coefficient, specific resistance, thermal conductivity, etc. of the thermoelectric material are changed, and other factors, including the performance index of the thermoelectric element alone, which can be predicted from the performance index Z of the thermoelectric material alone Often, the performance of thermoelectric elements actually manufactured differs. Therefore, in the actual evaluation of the thermoelectric element, the performance is determined based on the maximum temperature difference and the maximum heat absorption.
[0016]
In particular, if the maximum temperature difference is known, Z can be calculated backward, and the maximum endothermic amount can be calculated although some errors are assumed. That is, if the maximum temperature difference is known, it can be determined whether the thermoelectric performance of the thermoelectric element is high or low, that is, whether the thermoelectric performance of the Seebeck effect and the Peltier effect is excellent.
[0017]
Therefore, the performance evaluation of the created thermoelectric element is usually performed by measuring the maximum temperature difference.
[0018]
Here, as an example of a conventional method for measuring the maximum temperature difference of a thermoelectric element, there is a method disclosed in Non-Patent Document 1. This conventional technique will be described with reference to FIG.
[0019]
First, as shown in FIG. 11, a thermoelectric element 101 to be evaluated, which is a sample whose performance is to be measured, is brought into close contact with the upper part of the temperature control device 114 via thermal conductive grease.
[0020]
Next, the heat insulating member 1101 made of a heat insulating material is brought into close contact with the upper portion of the thermoelectric element 101 to be evaluated, and the weight member 1102 is placed on the heat insulating member 1101.
[0021]
Here, the temperature control device 114 is fixed on the base plate 113, and the support member 112, the slide member 110, and the fixing member 111 erected vertically upward from the base plate 113 move the weight member 1102 up and down. Can be.
[0022]
The weight member 1102 is made of a material that can be elastically deformed, and presses the heat insulating member 1101 downward with a constant force to apply a constant weight to the thermoelectric element 101 to be evaluated and make it adhere to the temperature control device 114.
[0023]
The temperature control device 114 includes a temperature measurement plate 103, a temperature control thermoelectric element 104, and a heat exchanger 106.
[0024]
A temperature sensor is embedded in the temperature measurement plate 103 near the surface in contact with the thermoelectric element 101 to be evaluated, and the temperature of the hot junction of the thermoelectric element 101 to be evaluated is measured. 104 is controlled.
[0025]
A temperature sensor is also embedded in the heat insulating member 1101 in the vicinity of the surface in contact with the thermoelectric element 101 to be evaluated, and measures the temperature of the cold junction of the thermoelectric element 101 to be evaluated.
[0026]
In this state, a current is caused to flow through the thermoelectric element 101 to be evaluated, and a temperature difference generated at both ends of the hot junction and the cold junction of the thermoelectric element 101 to be evaluated is measured.
[0027]
Here, the reason why a constant weight is applied to the contact surface between the evaluation target thermoelectric element 101 and the temperature control device 114 (the temperature measurement plate 103) through the heat conductive grease is that the hot junction of the evaluation target thermoelectric element 101 is precisely placed. This is because, in order to control the temperature to be constant, it is necessary to minimize the thermal resistance between the thermoelectric element 101 to be evaluated and the temperature adjusting device 114 (the temperature measuring plate 103) and to reduce the variation in the thermal resistance.
[0028]
That is, at the hot junction of the thermoelectric element 101 to be evaluated, heat corresponding to Joule heat (electric power) generated by the current flowing through the thermoelectric element 101 to be evaluated flows into the temperature control device 114, so that the thermal resistance therebetween increases. Due to the variation, a measurement error occurs in the temperature of the hot junction by a temperature difference obtained by multiplying the heat (unit: W) passing through the contact surface by the thermal resistance (unit: ° C / W) of the contact surface. .
[0029]
It is generally known that the thermal resistance of the contact area can be reduced by applying a certain degree of weight to the surface and the surface in close contact with heat conductive grease in order to maintain good heat conduction at the contact area between the surfaces. Have been.
For example, at the contact surface, 10 (kgf / cm ² ) Since the thermal resistance is known from the literature such that the thermal resistance in the case of close contact with the above vertical load is 1 cm ° C / W, the loss of the temperature difference due to the contact surface is correctly estimated. be able to. If they are not brought into close contact with a certain load, the thermal resistance of the contact surface cannot be estimated correctly.
Therefore, it is indispensable to evaluate the thermoelectric element by applying a constant weight so that the thermal resistance is as small and constant as possible.
[0030]
[Non-patent document 1]
Sidorenko, "Application of Laser Doppler Anemometer to Experimental Study of Dynamic Deformation of Heat Transfer Element" Proceedings of the XIV International Conference on Thermoelectrics, Russia, Physical-Technical Institute, June 27, 1995, p. 366
[0031]
[Problems to be solved by the invention]
However, when the weight is applied to increase the accuracy of measuring the temperature difference by keeping the thermal resistance of the hot junction small and constant, the performance is evaluated by the method of applying the weight with the heat insulating member and the weight member in the related art as described above. . Here, the heat-insulating member is made of a heat-insulating material. However, the heat conductivity is, of course, not zero and the heat is transmitted to some extent.
[0032]
Therefore, when the maximum temperature difference is measured in this state, heat flows into the cold junction from the outside through the heat insulating member, and the cold junction being measured is heated by the amount of the heat flow, and the temperature of the cold junction becomes lower. As a result, the measured temperature difference becomes smaller than the original maximum temperature difference.
[0033]
That is, there is a problem that the original maximum temperature difference cannot be accurately measured due to the inflow of heat from the outside.
[0034]
Therefore, it is impossible to actually measure an accurate maximum temperature difference by the conventional thermoelectric element evaluation method. For this reason, the maximum temperature difference can be predicted by theoretical calculation, but it is very difficult to confirm the quality of the thermoelectric element by actually measuring it.
[0035]
In particular, in the case of a small-sized thermoelectric element, the influence of the heat insulating member in contact with the thermoelectric element for applying a load becomes remarkable, so that the measurement error tends to be larger.
[0036]
[Object of the invention]
Therefore, an object of the present invention is to solve the above-mentioned problem, apply a weight to the thermoelectric element, make the thermal resistance of the contact portion small and constant, and further, make the inflow of heat from the outside at the cold junction of the thermoelectric element zero. Accordingly, an object of the present invention is to provide a structure of a thermoelectric element performance evaluation device capable of accurately measuring a maximum temperature difference and a method for evaluating the same.
[0037]
[Means for Solving the Problems]
In order to solve the above-described problems, a thermoelectric element performance evaluation apparatus and a thermoelectric element performance evaluation method of the present invention employ the following configurations.
[0038]
That is, the thermoelectric element performance evaluation device of the present invention includes a temperature control unit, a heat flow measurement unit, a heat flow control unit, a weighting unit, and a thermoelectric element to be evaluated, and a hot junction and a temperature adjustment unit of the thermoelectric element to be evaluated. Are connected in a heat conductive manner, the cold junction of the evaluation target thermoelectric element and one of the heat flow measuring means are connected in a heat conductive manner, the other of the heat flow measuring means and the heat flow controlling means are connected in a heat conductive manner, Thus, a constant weight is applied to a connection portion between the thermoelectric element to be evaluated and the temperature adjusting means.
A thermoelectric element performance evaluation device for applying a constant weight to a connection portion with an adjusting means.
Further, it is preferable that the heat flow measuring means has the same cross-sectional shape as the thermoelectric element to be evaluated.
Further, it is preferable that the heat flow measuring means measures a temperature of at least two points on a line parallel to a direction in which the heat flow flows at a substantially central portion of the cross section with a material having a uniform thermal conductivity and a uniform sectional shape. .
More preferably, the heat flow measuring means has a thermoelectric element and a temperature measuring plate.
Further, it is more preferable that the thermoelectric element to be evaluated and the heat flow measuring means are in a vacuum atmosphere.
Further, it is desirable to have a thin plate heater between the thermoelectric element to be evaluated and the heat flow measuring means.
The method for evaluating the performance of a thermoelectric element according to the present invention includes the steps of: maintaining a constant temperature of a hot junction of the thermoelectric element to be evaluated by a temperature adjusting means; controlling a heat flow of the heat flow measuring means to zero by a heat flow control means; And measuring two temperatures of a hot junction and a cold junction.
[0039]
[Action]
In the thermoelectric element performance evaluation apparatus of the present invention, the heat flow measuring means is connected to the evaluation target thermoelectric element, the heat flow measurement means is connected to the heat flow control means, and the evaluation target thermoelectric element is weighted with respect to the temperature adjustment means by the weighting means. By controlling the heat flow of the heat flow measuring means to zero by the pressing and the heat flow control means, the thermal resistance of the contact surface between the hot junction of the thermoelectric element to be evaluated and the temperature adjusting means becomes small and constant, and the cooling of the thermoelectric element to be evaluated External heat inflow at the contacts can be reduced to zero. Therefore, it is possible to accurately measure the maximum temperature difference in an ideal state where the heat absorption amount of the evaluation target thermoelectric element is zero. As a result, the quality of the thermoelectric element can be confirmed by actually measuring it, and a thermoelectric element having performance as evaluated can be provided to the user.
[0040]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an optimal embodiment of the configuration of the thermoelectric element performance evaluation device of the present invention will be described with reference to the drawings.
[0041]
(First Embodiment)
The structure and evaluation method of the thermoelectric element performance evaluation device according to the first embodiment of the present invention will be described with reference to FIGS.
[0042]
FIG. 1 is a structural diagram showing the overall configuration of the thermoelectric element performance evaluation device of the present invention. First, the temperature control device 114 is fixed on the base plate 113, and the hot junction of the evaluation target thermoelectric element 101, which is a sample whose performance is to be measured, is closely attached to the upper portion of the temperature control device 114 via the thermal conductive grease. .
[0043]
The temperature control device 114 specifically includes a temperature measurement plate 103, a temperature control thermoelectric element 104, and a heat exchanger 106, and the evaluation target thermoelectric element 101 is in close contact with the temperature measurement plate 103.
[0044]
The temperature measuring plate 103 measures the temperature of the hot junction of the thermoelectric element 101 to be evaluated, and controls the current of the thermoelectric element 104 so that the temperature becomes constant at the set temperature.
[0045]
Then, the heat flow measuring device 102 is bonded to the lower portion of the heat flow control device 115 with good heat conductivity, and the cold junction of the thermoelectric element 101 to be evaluated and the lower portion of the heat flow measuring device 102 are closely contacted with good heat conductivity.
[0046]
The heat flow control device 115 specifically includes a heat flow control thermoelectric element 105 and a heat exchanger 107, and the heat flow control thermoelectric element 105 is joined to the heat flow measurement device 102 with good heat conduction.
[0047]
Further, the heat flow control device 115 and the movable plate 109 are joined via an elastic weight spring 108, and the movable plate 109 is joined to the slide member 110.
[0048]
Here, the temperature control device 114 is fixed on the base plate 113, and the movable plate 109 moves up and down by the support pillar 112, the slide member 110, and the fixing member 111 erected vertically upward from the base plate 113. be able to.
[0049]
When the movable plate 109 moves up and down, the weight spring 108 and the heat flow control device 115 move up and down together with the movable plate 109. Here, by pushing down the movable plate 109 until the weight spring is contracted by a certain distance, the heat flow control device 115, the heat flow measuring device 102, the evaluation target thermoelectric element 101, and the temperature adjustment device 114 are weighted in the vertical direction, and the evaluation target thermoelectric element 101 A constant weight is applied to the temperature control device 114 so that the temperature control device 114 is in close contact.
[0050]
Then, all the structural members described above are contained in the vacuum chamber 116, and after setting the structural members described above, a vacuum is drawn.
[0051]
Here, as a characteristic structure of the present invention, the hot junction of the thermoelectric element 101 to be evaluated is in close contact with the temperature control device 114 with a constant load, and the cold junction of the thermoelectric element 101 to be evaluated is connected to the heat flow measuring device 102. Adhering.
[0052]
Then, the heat flow flowing into the cold junction of the thermoelectric element 101 to be evaluated is measured by the heat flow measuring device 102, and the temperature of the cold junction of the thermoelectric element 101 to be evaluated is measured at the same time. The current of the heat flow control thermoelectric element 105 is controlled so that the measured heat flow becomes zero.
[0053]
In this setting, a current is passed through the thermoelectric element 101 to be evaluated, and the maximum temperature difference generated at both ends of the hot junction and the cold junction of the thermoelectric element 101 to be evaluated is measured. It is possible to measure an accurate maximum temperature difference when the heat flow flowing from the cold junction is zero.
[0054]
By performing the above measurement in the vacuum chamber 116, the cold junction of the thermoelectric element 101 to be evaluated is prevented from dew condensation, and the heat flowing in and out from the side surface between the hot junction and the cold junction of the thermoelectric element 101 to be evaluated is insulated. Therefore, there is a feature that the measurement accuracy of the maximum temperature difference is further increased.
[0055]
FIG. 2 is a cross-sectional view illustrating a representative structure of the thermoelectric element 101 to be evaluated, the temperature adjusting thermoelectric element 104, and the heat flow controlling thermoelectric element 105 in the thermoelectric element performance evaluation device of the present invention. P-type thermoelectric semiconductors 201 and n-type thermoelectric semiconductors 202 are arranged alternately and regularly, and are wired by wiring electrodes 203 at both ends of each thermoelectric semiconductor. Are connected alternately in electrical series.
[0056]
Two lead electrodes 204 for connecting a lead wire for flowing a current are connected to the thermoelectric semiconductors at both ends connected in series.
Further, the wiring electrode 203, the extraction electrode 204, and the heat conductive plates 205 and 206 are respectively joined, one of which is a hot junction and the other is a cold contact. Both can be hot or cold junctions in the direction of current flow.
[0057]
In the case of cooling the thermoelectric element, for example, an electric current is applied so that the heat conductive plate 205 side in FIG. 2 becomes a cold junction, and when cooling, the amount of heat absorbed by the cold junction and the Joule heat generated by the current flowing through the thermoelectric element become heat junction. It is carried to the conductive plate 206 side. Therefore, unless the heat conduction plate 206 has a structure capable of dissipating the heat, heat accumulates and the temperature rises. And the temperature of the cold junction side also rises due to the influence.
[0058]
Further, when the heat conduction plate 205 is heated so as to be a hot junction, that is, when an electric current is applied, the heat conduction plate 206 becomes a cold junction, and the heat conduction plate 206 provides necessary heat. If the temperature is not maintained, the temperature will drop, and the temperature on the side of the heat conductive plate 205 to be heated will also drop due to the effect.
[0059]
That is, in order to cool, heat, or adjust the temperature of one of the thermoelectric elements, a heat sink that can sufficiently exchange heat with the other is indispensable.
[0060]
Therefore, in FIG. 1, the heat exchanger 106 is joined to the temperature control thermoelectric element 104, and the heat exchanger 107 is joined to the heat flow control thermoelectric element 105.
[0061]
Ceramics having good heat conductivity, such as aluminum nitride and alumina, are used for the heat conductive plates 205 and 206.
[0062]
As the thermoelectric material, an alloy made of BiTeSb is used for the p-type thermoelectric semiconductor 201, and an alloy made of BiTeSe is used for the n-type thermoelectric semiconductor 202. However, the thermoelectric material is not limited to this, and various thermoelectric materials such as other BiTe-based materials and FeSi-based materials can be used depending on applications.
[0063]
FIG. 3 is a perspective view of the temperature control device 114. The temperature control thermoelectric element 104 is joined to the upper part of the heat exchanger 106 with good heat conduction, and the temperature measuring plate 103 is joined to the upper part of the temperature control thermoelectric element 104 with good heat conduction.
[0064]
Each of the structural members is fixed with a heat conductive adhesive or fixed with a heat conductive grease and screwed.
[0065]
The temperature measuring plate 103 embeds a temperature sensor 301 such as a thermistor or a platinum resistance thermometer near the surface in contact with the thermoelectric element 101 to be evaluated, measures the temperature of the hot junction of the thermoelectric element 101 to be evaluated, The signal is fed back to control the current flowing through the lead wire 302 for supplying the current to the temperature adjusting thermoelectric element 104 such that the temperature of the hot junction of the thermoelectric element 101 to be evaluated maintains a constant temperature.
[0066]
The structure of the temperature adjusting thermoelectric element 104 is the same as the structure of the general thermoelectric element shown in FIG. 2, and uses a thermoelectric element that is considerably larger than the thermoelectric element 101 to be evaluated.
[0067]
The heat exchanger 106 has an inside of a closed cavity, fills the inside with a liquid capable of carrying heat such as water, and has a circulation path 303 through which the liquid flows in and out. Circulate to keep the temperature constant.
[0068]
In this manner, heat that enters and exits the heat exchanger 106 via the hot junction of the temperature control thermoelectric element 104 can be taken in and out, and the temperature of the hot junction of the thermoelectric element 101 to be evaluated can be precisely controlled. it can.
[0069]
As a specific example of such a system, a combination of SL-10W and SL-CP1206 of Nippon Blower Co., Ltd. may be mentioned.
[0070]
The heat exchanger 106 is of a water circulation type that is easy to configure because of its structure in the vacuum chamber 116. However, if the heat exchanger 106 is provided on the wall surface of the vacuum chamber 116, the fins and other parts that exchange heat with the outside air can be vacuumed. Since it can be taken out of the chamber, an air-cooled type is also possible.
[0071]
FIG. 4 is a perspective view of the movable plate 109, the weight spring 108, the heat flow control device 115, and the heat flow measuring device 102.
[0072]
As shown in FIG. 4, a load spring 108 is joined to a lower portion of the movable plate 109, a heat heat exchanger 107 is joined to a lower portion of the load spring 108, and a heat flow control thermoelectric element 105 is connected to a lower portion of the heat exchanger 107 by heat conduction. The heat flow measuring device 102 is bonded to the lower portion of the heat flow controlling thermoelectric element 105 with good heat conduction.
[0073]
Each of the structural members is fixed with a heat conductive adhesive or fixed with a heat conductive grease and screwed.
[0074]
FIG. 5 is a perspective view of the heat flow measuring device 102. The heat flow measuring device 102 is made of a material having uniform thermal conductivity, has the same cross-sectional shape as the thermoelectric element 101 to be evaluated, and has a central portion of the cross-sectional shape, and a cold junction of the thermoelectric element 101 to be evaluated. Two temperature sensors 501 and 502 such as a thermistor or a platinum resistance temperature sensor are embedded in the vicinity of the contacting surface and the contacting surface of the heat flow control thermoelectric element 105, and the temperature of the cold junction of the thermoelectric element 101 to be evaluated is measured by the temperature sensor 501. At the same time, the temperature near the surface in contact with the heat flow control thermoelectric element 105 is measured by the temperature sensor 502.
[0075]
Then, the signals from the temperature sensors 501 and 502 are fed back to control the current flowing through the lead wire 401 for applying current to the heat flow control thermoelectric element 105 so that the two temperatures of the temperature sensors 501 and 502 become the same temperature. .
[0076]
In general heat transfer theory, if the temperature of two points separated by a certain distance in the direction perpendicular to the cross section of a member having uniform heat conductivity and uniform cross section is the same, the member passes through that cross section. Heat flow is zero.
[0077]
Therefore, when the temperatures of the temperature sensors 501 and 502 are the same as described above, the heat flow that moves the heat flow measuring device in the vertical direction becomes zero.
[0078]
At this time, if the cross-sectional shapes of the evaluation target thermoelectric element 101 and the heat flow measuring device 102 are the same, the heat flow becomes linear and uniform, and thus the effect of improving the sensitivity of the heat flow measurement is obtained.
[0079]
The structure of the heat flow controlling thermoelectric element 105 is the same as the structure of the general thermoelectric element shown in FIG. 2, and uses a thermoelectric element that is considerably larger than the thermoelectric element 101 to be evaluated, like the thermoelectric element 104. The structure of the heat exchanger 107 is the same as that of the heat exchanger 106.
[0080]
The movable plate 109 is joined to a slide member and can be moved horizontally up and down. The movable plate 109 and the heat exchanger 107 (heat flow control device 115) are a plurality of the same weighted springs arranged in a plane. Connected at 108. Therefore, when the thermoelectric element 101 to be evaluated is sandwiched between the temperature measurement plate 103 and the heat flow measuring device 102 and brought into close contact with each other, variations in the parallelism of the respective contact surfaces can be absorbed by the weighted spring 108, and the heat conduction can be achieved with good heat conduction. Can be done.
[0081]
In addition, by adjusting the contraction length of the weight spring 108, the weight can be arbitrarily adjusted.
[0082]
With the above structure, the heat flow of the heat flow measuring device 102 can be reduced to zero, and at the same time, the thermoelectric element 101 to be evaluated can be brought into close contact with the temperature measuring plate 103 with a constant load.
[0083]
Further, the heat flow control thermoelectric element 105 shown in FIG. 4 has one stage, but by adopting a structure in which two thermoelectric elements having different sizes are stacked, rough temperature control is performed by the first stage thermoelectric element, By performing fine temperature control with the second-stage thermoelectric element, the control range is expanded, and the accuracy of heat flow control (temperature adjustment) can be improved.
[0084]
Furthermore, since the heat flow passing through the heat flow measuring device 102 and the temperature difference between the temperature sensors 501 and 502 are proportional, the heat flow measuring device 102 is made of a material whose thermal conductivity is accurately known, so that the temperature sensor 501 is formed. , 502, the heat flow can be calculated.
[0085]
In this case, the temperature difference generated at both ends of the hot junction and the cold junction of the thermoelectric element 101 to be evaluated is smaller than the maximum temperature difference by the amount of the heat flow. Therefore, the evaluation can be made by the calculated value without controlling the heat flow to zero.
[0086]
FIG. 6 is a diagram illustrating a control system of the temperature control device 114. The heat exchanger 106 is connected to a constant temperature water circulation device 607 outside the vacuum chamber. As described above, the inside of the heat exchanger 106 has the circulation path 303 for introducing and discharging the constant temperature water, and quickly reacts to the inflow and outflow of heat from the temperature control thermoelectric element 104 to maintain the constant temperature.
[0087]
The temperature measurement plate 103 is connected to a temperature conversion circuit 601 that converts a signal of the temperature sensor 301 into a temperature. The temperature conversion circuit 601 is connected to a current control circuit 602 that controls the current of the thermostat 104. The current control circuit 602 is connected to a power supply circuit 603 and an external outlet 604 ahead of the power supply circuit 603. The current control circuit 602 is connected to a display unit that displays the real-time temperature and the set temperature, and a console 605 where switches for changing settings are collected. And one control device 606 is formed.
[0088]
The current control circuit 602 controls the current flowing through the temperature adjusting thermoelectric element 104 by feedback control (for example, PID control) of the temperature measured by the temperature sensor 301 so that the temperature measured by the temperature sensor 301 becomes the set temperature. With such a control method, a set temperature of about ± 0.1 ° C. can be realized with accuracy.
[0089]
FIG. 7 is a diagram illustrating a control system of the heat flow control device 115. The structure of the heat exchanger 107, the circulation path 402, and the constant temperature water circulation device 707 is the same as the peripheral structure of the heat exchanger 607 described in FIG.
[0090]
The heat flow measuring device 102 is connected to a temperature conversion circuit 701 that converts signals from the temperature sensors 501 and 502 into temperature. The temperature conversion circuit 701 is connected to a current control circuit 702 that controls the current of the heat flow control thermoelectric element 105. The current control circuit 702 is connected to a power supply circuit 703 and an external outlet 704 ahead of the power supply circuit 703. The current control circuit 702 is connected to a console 705 on which a display unit for displaying the real-time temperature and the temperature difference, a switch for changing a setting, and the like are collected. And one control device 706 is formed.
[0091]
The current control circuit 702 feeds back the temperatures measured by the temperature sensors 501 and 502 so that the temperatures measured by the temperature sensors 501 and 502 become the same, that is, the temperature difference between the temperature sensors 501 and 502 becomes zero. The current flowing through the heat flow control thermoelectric element 105 is controlled by control (for example, PID control).
[0092]
As a feature of the present invention, by using the above-described means, it is possible to control the heat flow passing through the heat flow measuring device 102 to be zero, and the hot junction of the thermoelectric element 101 to be evaluated is fixed to the temperature measuring plate 103. And the inflow and outflow of heat from the cold junction of the thermoelectric element 101 to be evaluated can be made zero, and the temperature (temperature difference) between the hot junction and the cold junction of the thermoelectric element 101 to be evaluated at that time is measured. Thus, the maximum temperature difference can be measured accurately and accurately.
[0093]
(Second embodiment)
Next, a structure and an evaluation method of the thermoelectric element performance evaluation device according to the second embodiment of the present invention will be described with reference to FIG.
[0094]
FIG. 8 shows another structure of the heat flow measuring device 102 whose structure has been described with reference to FIG. 5 in the first embodiment. As shown in FIG. 8, one of the heat flow measuring thermoelectric elements 801 and the temperature measuring plate 804 are joined with a heat conductive adhesive or the like as the heat flow measuring device 102 with good heat conductivity, and the other of the heat flow measuring thermoelectric elements 801 is connected to the heat flow controlling thermoelectric element. 105 with good thermal conductivity.
[0095]
A temperature sensor 804 such as a thermistor or a platinum resistance temperature detector is embedded near the surface of the temperature measurement plate 803 that is not joined to the heat flow measurement thermoelectric element 801, and is closely adhered to the thermoelectric element 101 to be evaluated. The temperature of the cold junction of the target thermoelectric element 101 is measured.
[0096]
The structural features of the second embodiment are the same as those of the first embodiment except that the heat flow measuring device 102 is replaced with the structure shown in FIG.
[0097]
The heat flow passing through the heat flow measurement thermoelectric element 801 is proportional to the temperature difference between the cold junction and the hot junction of the heat flow measurement thermoelectric element 801, and the temperature difference between the cold junction and the hot junction of the heat flow measurement thermoelectric element 801 and the heat flow measurement thermoelectric element 801. Is proportional to the voltage generated. That is, the heat flow passing through the heat flow measuring thermoelectric element 801 is proportional to the voltage generated by the heat flow measuring thermoelectric element 801. That is, by controlling the current of the heat flow control thermoelectric element 105 so that the voltage generated by the heat flow measurement thermoelectric element 801 becomes zero, the heat flow passing through the heat flow measurement thermoelectric element 801 can be made zero.
[0098]
FIG. 9 is a diagram illustrating a control system of the heat flow control device 115 according to the second embodiment.
[0099]
The heat flow measurement device 102 is connected to a current control circuit 902 that controls the current of the heat flow control thermoelectric element 105 by a lead wire 802 of the heat flow measurement thermoelectric element 801. Further, the heat flow measurement device 102 is connected to a temperature conversion circuit 901 that converts a signal of the temperature sensor 804 of the temperature measurement plate 803 into a temperature. The temperature conversion circuit 901 is connected to the current control circuit 902. The current control circuit 902 is connected to a power supply circuit 703 and an external outlet 704 ahead of the power supply circuit 703. The current control circuit 902 is connected to a display unit for displaying the real-time temperature and voltage, a console 903 for collecting switches for changing settings, and the like.
[0100]
In the current control circuit 902, the heat flow measurement thermoelectric element 801 is set so that the voltage measured by the heat flow measurement thermoelectric element 801 becomes zero, that is, the temperature difference between the hot junction and the cold junction of the heat flow measurement thermoelectric element 801 becomes zero. The current flowing through the heat flow control thermoelectric element 105 is controlled by feedback control (for example, PID control or the like) of the measured voltage.
[0101]
The heat flow measuring device 102 having the structure shown in FIG. 5 uses the temperature sensors 501 and 502 such as a thermistor and a platinum resistance temperature detector to measure the heat flow. There is a possibility that the response speed for detecting the temperature may be slightly reduced by the heat capacity of the coating material or the like.
[0102]
However, the heat flow measuring device 102 having the structure shown in FIG. 8 has a wasteful heat capacity that slows down the response speed because the heat flow flows only through the thermoelectric material of the heat flow measuring thermoelectric element 801 and the thermoelectric material itself is a temperature difference detecting portion. Do not have. Therefore, the heat flow measuring device 102 having the structure shown in FIG. 8 can increase the response speed to the heat flow as compared with the heat flow measuring device 102 having the structure shown in FIG. .
[0103]
Also, in general, a value obtained by multiplying a logarithm by a temperature difference is proportional to a generated voltage, so that as the logarithm of the heat flow measuring thermoelectric element 801 increases, the detected voltage increases. By increasing the logarithm, the sensitivity of the voltage for detecting the heat flow is increased, the measurement accuracy can be greatly improved, and the more accurate measurement of the maximum temperature difference becomes possible.
[0104]
(Third embodiment)
Next, a structure and an evaluation method of the thermoelectric element performance measuring device according to the third embodiment of the present invention will be described with reference to FIG.
[0105]
As shown in FIG. 10, a structural feature of the third embodiment is that a heater 1001 is inserted between a thermoelectric element 101 to be evaluated and a heat flow meter 102. Here, by controlling the amount of heat of the heater 1001 by controlling the heat flow passing through the heat flow measuring device 102 to zero by the same method described in the first embodiment and the second embodiment, It is possible to actually measure not only the maximum temperature difference of the evaluation target thermoelectric element 101 but also the maximum heat absorption amount estimated by the assumption calculation from the maximum temperature difference.
[0106]
In the first embodiment, the second embodiment, and the third embodiment, through the lead wires of the temperature sensors 501, 502, and 804 of the heat flow measuring device 102 and the lead wires 802 of the heat flow measuring thermoelectric element 801 A small amount of heat can come and go. When the thermoelectric element 101 to be evaluated and the heat flow measuring device 102 are small in size, even a small amount of heat is affected, which may cause a large error. As a countermeasure, although not shown, by adopting a structure in which the above-mentioned lead wire is brought into contact with the heat flow controlling thermoelectric element 105, heat entering and exiting through the lead wire can be reduced to zero, and the evaluation of a small-sized thermoelectric element is also high. Can be done with precision.
[0107]
In the first embodiment, the second embodiment and the third embodiment, two heat exchangers 106 and 107 are used. Is also possible. In this case, the measurement margin is improved by using two-stage thermoelectric elements for the heat flow control thermoelectric elements 105 in order to widen the measurement range.
[0108]
【The invention's effect】
As is clear from the above description, the thermoelectric element performance evaluation device of the present invention connects the heat flow measuring means to the evaluation target thermoelectric element, connects the heat flow measurement means to the heat flow control means, and applies the weighting means to the evaluation target thermoelectric element. The thermal resistance of the contact surface between the hot junction of the thermoelectric element to be evaluated and the temperature control means is kept small and constant by controlling the heat flow of the heat flow measurement means to zero by pressing against the temperature control means with a constant weight and controlling the heat flow of the heat flow measurement means to zero by the heat flow control means. And the inflow of heat from the outside at the cold junction of the thermoelectric element to be evaluated can be reduced to zero. Therefore, it is possible to accurately measure the maximum temperature difference in an ideal state where the heat absorption amount of the evaluation target thermoelectric element is zero.
[0109]
Further, by using the thermoelectric element as the heat flow measuring means, the response speed to the heat flow can be increased, and thus there is an advantage that the measurement accuracy is further improved.
[0110]
Then, by connecting the lead wire coming out of the heat flow measuring means to the heat flow control means, heat flowing in and out of the lead wire can be cut off, and accurate measurement can be performed even on a small thermoelectric element.
[0111]
Furthermore, by providing a heater between the thermoelectric element to be evaluated and the heat flow measuring means, by measuring the amount of heat, it is possible to actually measure not only the maximum temperature difference of the thermoelectric element to be evaluated but also the maximum heat absorption. It becomes possible.
[0112]
As a result, the quality of the thermoelectric element can be confirmed by actually measuring it, and a thermoelectric element having performance as evaluated can be provided to the user.
[Brief description of the drawings]
FIG. 1 is a structural diagram showing an overall configuration of a thermoelectric element performance evaluation device according to a first embodiment of the present invention.
FIG. 2 is a cross-sectional view of a thermoelectric element of the thermoelectric element performance evaluation device according to the first embodiment of the present invention.
FIG. 3 is a perspective view of a temperature control device of the thermoelectric element performance evaluation device according to the first embodiment of the present invention.
FIG. 4 is a perspective view of a movable plate, a weight spring, a heat flow control device, and a heat flow measuring device of the thermoelectric element performance evaluation device according to the first embodiment of the present invention.
FIG. 5 is a perspective view of a heat flow measuring device of the thermoelectric element performance evaluation device according to the first embodiment of the present invention.
FIG. 6 is a control system diagram of a temperature control device of the thermoelectric element performance evaluation device according to the first embodiment of the present invention.
FIG. 7 is a control system diagram of a heat flow control device of the thermoelectric element performance evaluation device according to the first embodiment of the present invention.
FIG. 8 is another structural diagram of a heat flow measuring device of the thermoelectric element performance evaluation device according to the second embodiment of the present invention.
FIG. 9 is a control system diagram of a heat flow control device of the thermoelectric element performance evaluation device according to the second embodiment of the present invention.
FIG. 10 is a structural diagram illustrating an overall configuration of a thermoelectric element performance evaluation device according to a third embodiment of the present invention.
FIG. 11 is a structural diagram showing an overall configuration of a conventional thermoelectric element performance evaluation device.
[Explanation of symbols]
101 Thermoelectric element to be evaluated
102 Heat flow meter
103, 803 Temperature measuring plate
104 Temperature control thermoelectric element
105 Heat flow control thermoelectric element
106, 107 heat exchanger
108 Weight spring
109 movable plate
110 slide member
111 fixing member
112 support column
113 Baseboard
114 Temperature controller
115 Heat flow control device
116 vacuum chamber
201 p-type thermoelectric semiconductor
202 n-type thermoelectric semiconductor
203 Wiring electrode
204 Leader electrode
205 206 Thermal conductor
301, 501, 502, 804 Temperature sensor
302, 401 Lead wire
303, 402 circulation path
601, 701, 901 Temperature conversion circuit
602, 702, 902 Current control circuit
603, 703 power supply circuit
604, 704 External outlet
605, 705, 903 console
606, 706 control device
607, 707 Constant temperature water circulation device
1001 heater
1101 Heat insulation member
1102 Weight member

Claims

Temperature control means, heat flow measurement means, heat flow control means, weighting means, and a thermoelectric element to be evaluated, and a hot junction of the thermoelectric element to be evaluated and the temperature adjustment means are connected so as to be capable of conducting heat, The cold junction of the thermoelectric element to be evaluated and one of the heat flow measuring means are connected so as to be able to conduct heat, the other of the heat flow measuring means is connected to the heat flow controlling means so as to be able to conduct heat, and the evaluation object is connected by the weighting means. A thermoelectric element performance evaluation device for applying a constant weight to a connection portion between the thermoelectric element and the temperature adjusting means.

The thermoelectric element performance evaluation device according to claim 1, wherein the heat flow measuring unit has the same cross-sectional shape as the thermoelectric element to be evaluated.

The heat flow measuring means has a uniform cross-sectional shape with a material having a uniform thermal conductivity, and measures temperatures of at least two points on a line parallel to a direction in which a heat flow flows at a substantially central portion of the cross section. The thermoelectric element performance evaluation device according to claim 1 or 2, wherein:

The thermoelectric element performance evaluation device according to claim 1, wherein the heat flow measuring means includes a thermoelectric element and a temperature measuring plate.

The thermoelectric element performance evaluation device according to any one of claims 1 to 4, wherein the evaluation target thermoelectric element and the heat flow measuring means are in a vacuum atmosphere.

The thermoelectric element performance evaluation device according to any one of claims 1 to 5, further comprising a thin plate heater between the evaluation target thermoelectric element and the heat flow measuring unit.

Temperature control means, heat flow measurement means, heat flow control means, weighting means, and a thermoelectric element to be evaluated, and a hot junction of the thermoelectric element to be evaluated and the temperature control means are connected so as to be able to conduct heat; The cold junction of the thermoelectric element to be evaluated and one of the heat flow measuring means are connected so as to be able to conduct heat, the other of the heat flow measuring means is connected to the heat flow controlling means so as to be able to conduct heat, and the evaluation object is connected by the weighting means. A structure for applying a constant weight to a connection portion between the thermoelectric element and the temperature control means, maintaining a constant temperature of a hot junction of the thermoelectric element to be evaluated by the temperature control means, and measuring the heat flow by the heat flow control means; A thermoelectric element performance evaluation method for evaluating the performance of a thermoelectric element by controlling a heat flow of a means and measuring two temperatures of a hot junction and a cold junction of the thermoelectric element to be evaluated.

The method for evaluating the performance of a thermoelectric element according to claim 7, wherein the heat flow control means is controlled so that the heat flow of the heat flow measurement means becomes zero.