JP4234475B2

JP4234475B2 - Thermoelectric element performance evaluation apparatus and thermoelectric element performance evaluation method

Info

Publication number: JP4234475B2
Application number: JP2003089588A
Authority: JP
Inventors: 淳村上; 滋渡辺
Original assignee: Citizen Holdings Co Ltd; Citizen Watch Co Ltd
Current assignee: Citizen Holdings Co Ltd; Citizen Watch Co Ltd
Priority date: 2003-03-28
Filing date: 2003-03-28
Publication date: 2009-03-04
Anticipated expiration: 2023-03-28
Also published as: JP2004296959A

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／ｃｍ²）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（APPLICATION OF LASER DOPPLER ANEMOMETRY FOR EXPERIMENTAL INVESTIGATION OF THERMOELECTRIC ELEMENTS DYNAMIC DEFORMATION）」,第１４回国際熱電学会会報（Proceedings of the XIV International Conference on Thermoelectrics）,ロシア,物理技術研究所（Physical-Technical Institute）,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]
BACKGROUND OF THE INVENTION
The present invention relates to a thermoelectric element used in a thermoelectric generator using the Seebeck effect or a Peltier element used in a thermoelectric cooling apparatus using the Peltier effect, and more particularly to the structure and evaluation method of a thermoelectric element or a performance evaluation apparatus for a Peltier element.
[0002]
[Prior art]
A thermoelectric element is a device that can directly convert thermal energy into electrical energy and electrical energy into thermal energy.
[0003]
The structure of a general thermoelectric element is that a p-type thermoelectric semiconductor having a columnar p-type thermoelectric semiconductor and an n-type thermoelectric semiconductor are formed in pairs at substantially the same length, and a plurality of the thermocouples are arranged in a plane. 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. Further, when a direct current is passed through the thermoelectric element, the Peltier effect absorbs heat at one end and releases heat (heat generation) at the other end.
[0005]
The thermoelectric element is a device having such a reversible effect, and is applied to various apparatuses as a conversion element between heat energy and electric energy.
[0006]
By using the Seebeck effect of thermoelectric elements, thermal energy can be directly converted into electrical energy, so thermoelectric power generators that generate power using waste heat are attracting attention as an effective method of using thermal energy. I am scared.
[0007]
Further, by utilizing the Peltier effect of the thermoelectric element, if a suitable heat source is connected to the heat absorbing side of the thermoelectric element with good heat conduction, it can be used as a thermoelectric cooling device for cooling the heat source.
[0008]
In addition, by adjusting the current flowing through the thermoelectric element, it can be used not only for cooling but also as a temperature adjusting device that maintains a constant temperature.
[0009]
In particular, a thermoelectric element using the Peltier effect, such as a thermoelectric cooling device, may be referred to as a Peltier element from the name of the effect, but in the description of the present invention, it will be referred to as a thermoelectric element.
[0010]
Unlike other types of cooling devices, the thermoelectric cooling device does not include mechanical parts such as compressors and can be downsized, so it can be portable portable refrigerators, and can be locally applied to heat sources such as integrated circuits and laser light sources. It is used as a cooling device or a temperature control device. In particular, laser diodes used in the field of optical communications and DVD pickups are broken or their performance deteriorates significantly at high temperatures. Therefore, in the field of optical communications, the laser diode is cooled and temperature control is controlled to a constant temperature. Is an indispensable technique, and thermoelectric elements are generally used in the field of optical communication.
[0011]
Here, a conventional performance evaluation method for thermoelectric elements will be described. 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 flowing in from the cold junction (the amount of heat absorbed) to zero, a direct current is passed and the current is gradually increased. And the other end forming the thermocouple of the thermoelectric element absorbs heat, dissipates heat (heat generation) at the hot junction, the hot junction is kept at a constant temperature, the cold junction gradually decreases in temperature, The temperature difference gradually increases. This effect is called the Peltier effect.
[0012]
The temperature difference becomes maximum at a certain current, and when the current is increased further, the temperature difference gradually decreases. This maximum temperature difference is called the maximum temperature difference. Since this maximum temperature difference is proportional to the figure of merit Z representing the performance of the thermoelectric element, the maximum temperature difference is an index representing the performance of the thermoelectric element.
[0013]
In addition, when the current is gradually increased so that the temperature difference between the hot junction and the cold junction of the thermoelectric element is kept at zero, the amount of heat flowing in from the cold junction (the amount of heat absorbed) gradually increases. Maximum. This amount of heat is referred to as the maximum endothermic amount, and this maximum endothermic amount is an index representing the performance of the thermoelectric element in the same manner as the maximum temperature difference.
[0014]
The figure of merit Z is obtained by dividing the square of the Seebeck coefficient of the material of the thermoelectric element by 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 when the thermoelectric material is processed and assembled into a thermoelectric element.
[0015]
And, in the process of assembling the thermoelectric element, the thermoelectric element performance that can be predicted from the figure of merit Z of the thermoelectric material alone, including changes in the Seebeck coefficient, specific resistance, thermal conductivity, etc. of the thermoelectric material, and other factors Often, the performance of actually produced thermoelectric elements is different. Therefore, in the actual evaluation of the thermoelectric element, the performance is judged by the maximum temperature difference and the maximum heat absorption amount.
[0016]
In particular, if the maximum temperature difference is known, Z can be calculated backwards, and the maximum heat absorption amount can be calculated with some assumption errors included. 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]
For this reason, performance evaluation of the created thermoelectric element is usually performed by measuring the maximum temperature difference.
[0018]
Here, as an example of a method for measuring the maximum temperature difference of a conventional thermoelectric element, there is a method disclosed in Non-Patent Document 1. This prior art will be described with reference to FIG.
[0019]
First, as shown in FIG. 11, the thermoelectric element 101 to be evaluated, which is a sample whose performance is to be measured, is brought into close contact with the upper portion of the temperature control device 114 via thermally conductive grease.
[0020]
Next, a heat insulating member 1101 made of a heat insulating material is brought into close contact with the upper portion of the evaluation target thermoelectric element 101, 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 weight member 1102 moves up and down by the support column 112, the slide member 110, and the fixing member 111 that are vertically raised from the base plate 113. Can do.
[0022]
The weight member 1102 is made of a material that can be elastically deformed, and the thermoelectric element 101 to be evaluated is brought into close contact with the temperature adjustment device 114 by applying a certain load by pressing the heat insulating member 1101 downward with a constant force.
[0023]
The temperature adjustment device 114 includes a temperature measurement plate 103, a temperature adjustment thermoelectric element 104, and a heat exchanger 106.
[0024]
A temperature sensor is embedded in the temperature measurement plate 103 in the vicinity of the surface in contact with the evaluation target thermoelectric element 101, the temperature of the hot junction of the evaluation target thermoelectric element 101 is measured, and the temperature adjustment thermoelectric element is adjusted so that the temperature becomes constant. 104 current is controlled.
[0025]
Also, a temperature sensor is embedded in the heat insulating member 1101 in the vicinity of the surface in contact with the evaluation target thermoelectric element 101, and the temperature of the cold junction of the evaluation target thermoelectric element 101 is measured.
[0026]
In this state, a current is passed through the evaluation target thermoelectric element 101, and the temperature difference generated between the hot junction and the cold junction of the evaluation target thermoelectric element 101 is measured.
[0027]
Here, a constant load is applied to the contact surface between the evaluation target thermoelectric element 101 and the temperature control device 114 (temperature measurement plate 103) via the thermal conductive grease to precisely set the hot junction of the evaluation target thermoelectric element 101. This is because in order to control to a constant temperature, it is necessary to make the thermal resistance between the evaluation target thermoelectric element 101 and the temperature control device 114 (temperature measurement plate 103) as small as possible and to reduce the variation in thermal resistance.
[0028]
That is, at the hot junction of the evaluation target thermoelectric element 101, the heat for the Joule heat (electric power) generated by the current flowing through the evaluation target thermoelectric element 101 flows into the temperature control device 114. Variation causes a measurement error in the temperature of the hot junction by a temperature difference obtained by multiplying the heat passing through the contact surface (unit: W) and the thermal resistance of the contact surface (unit: ° C / W). .
[0029]
It is generally known that the thermal resistance of the contact area can be reduced by applying a certain amount of weight to the contact area between the surfaces, in order to maintain good heat conduction by bringing the surfaces into close contact with thermal conductive grease. It has been.
For example, the contact surface is 10 (kgf / cm through a thermally conductive grease. ² ) Since the thermal resistance value is known from the literature such that the thermal resistance when in 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 the contact is not made with a constant load, the thermal resistance of the contact surface cannot be estimated correctly.
Therefore, it is indispensable to apply a constant weight so as to make the thermal resistance as small and constant as possible in evaluating the thermoelectric element.
[0030]
[Non-Patent Document 1]
Sidorenko, “APPLICATION OF LASER DOPPLER ANEMOMETRY FOR EXPERIMENTAL INVESTIGATION OF THERMOELECTRIC ELEMENTS DYNAMIC DEFORMATION”, 14th International Thermoelectric Society Bulletin ( 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 applying a weight in order to increase the measurement accuracy of the temperature difference by keeping the thermal resistance of the hot junction small and constant, as described above, in the prior art, the performance evaluation is performed by the method of applying the weight by the heat insulating member and the weighting member. . Here, the heat insulating member is made of a heat insulating material. Naturally, the thermal conductivity is not zero, and heat is passed to some extent.
[0032]
Therefore, when the maximum temperature difference is measured in this state, heat flows in from the outside through the heat insulating member at the cold junction, and the cold junction being measured is warmed by the inflow of the heat. 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 has been impossible to actually measure the maximum temperature difference with the conventional thermoelectric element evaluation method. For this reason, although the maximum temperature difference by theoretical calculation can be predicted, there is a problem that it is very difficult to confirm the quality of the thermoelectric element by actual measurement.
[0035]
In particular, in the case of a small thermoelectric element, the influence of the heat insulating member that comes into contact with the load becomes significant, so that the measurement error tends to be larger.
[0036]
(Object of invention)
Therefore, the 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 make the inflow of heat from the outside at the cold junction of the thermoelectric element zero. Thus, an object of the present invention is to provide a structure of a thermoelectric device performance evaluation apparatus capable of measuring an accurate maximum temperature difference and an evaluation method thereof.
[0037]
[Means for Solving the Problems]
In order to solve the above-described problems, the thermoelectric element performance evaluation apparatus and the thermoelectric element performance evaluation method of the present invention employ the configurations described below.
[0038]
That is, the thermoelectric element performance evaluation apparatus of the present invention comprises a temperature adjusting means, a heat flow measuring means, a heat flow control means, a weighting means, and an evaluation target thermoelectric element, and a hot junction of the evaluation target thermoelectric element and a temperature adjusting 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 to be able to conduct heat, the other of the heat flow measuring means and the heat flow controlling means are connected to be able to conduct heat, and the weighting means Thus, a certain weight is applied to the connection portion between the thermoelectric element to be evaluated and the temperature adjusting means.
A thermoelectric device performance evaluation apparatus that applies a constant weight to a connection portion with the adjusting means.
Moreover, it is preferable that a heat flow measurement means is the same cross-sectional shape as a 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 the direction in which the heat flow flows at a substantially central portion of the cross section with a material having a uniform thermal conductivity. .
More preferably, the heat flow measuring means has a thermoelectric element and a temperature measuring plate.
Further, the evaluation target thermoelectric element and the heat flow measuring means are preferably in a vacuum atmosphere.
Furthermore, it is desirable to have a thin plate heater between the thermoelectric element to be evaluated and the heat flow measuring means.
In addition, the thermoelectric element performance evaluation method of the present invention maintains the temperature of the hot junction of the evaluation target thermoelectric element constant by the temperature adjustment means, and controls the heat flow of the heat flow measurement means to zero by the heat flow control means, It measures the two temperatures of the hot junction and the cold junction.
[0039]
[Action]
In the thermoelectric element performance evaluation apparatus of the present invention, the heat flow measurement 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 to the temperature adjustment means by the weighting means. By pressing and controlling the heat flow of the heat flow measuring means to zero by the heat flow control means, the thermal resistance of the contact surface between the hot junction of the evaluation target thermoelectric element and the temperature adjusting means becomes small and constant, and the evaluation target thermoelectric element is cooled. The inflow of heat from the outside at the contact can be made zero. Therefore, an accurate maximum temperature difference can be measured in an ideal state where the endothermic 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 the thermoelectric element having the performance as evaluated can be provided to the user.
[0040]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an optimal embodiment in the configuration of a thermoelectric element performance evaluation apparatus 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 apparatus 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 apparatus of the present invention. First, the temperature control device 114 is fixed to the upper part of the base plate 113, and the hot junction of the thermoelectric element 101 to be evaluated, which is a sample whose performance is to be measured, is adhered to the upper part of the temperature control device 114 through the heat conductive grease. .
[0043]
Specifically, the temperature adjustment device 114 includes a temperature measurement plate 103, a temperature adjustment 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 evaluation target thermoelectric element 101 and controls the current of the temperature adjusting thermoelectric element 104 so that the temperature becomes constant at the set temperature.
[0045]
Then, the heat flow measuring device 102 is joined to the lower portion of the heat flow control device 115 with good heat conduction, and the cold junction of the thermoelectric element 101 to be evaluated and the lower portion of the heat flow measuring device 102 are brought into close contact with good heat conduction.
[0046]
Specifically, the heat flow control device 115 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 measuring instrument 102 with good heat conduction.
[0047]
Further, the heat flow control device 115 and the movable plate 109 are joined via a weighted spring 108 having elasticity, and the movable plate 109 is joined to the slide member 110.
[0048]
Here, the temperature adjusting device 114 is fixed on the base plate 113, and the movable plate 109 moves up and down by the support column 112, the slide member 110, and the fixed member 111 that are vertically raised from the base plate 113. be able to.
[0049]
When the movable plate 109 moves up and down, the load spring 108 and the heat flow control device 115 move up and down together with the movable plate 109. Here, by depressing the movable plate 109 until the weighted spring contracts 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 load is applied to the temperature control device 114 so as to be in close contact.
[0050]
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 evaluation target thermoelectric element 101 is in close contact with the temperature adjusting device 114 with a certain load, and the cold junction of the evaluation target thermoelectric element 101 is connected to the heat flow measuring device 102. It is in close contact.
[0052]
Then, the heat flow measuring device 102 measures the heat flow flowing into the cold junction of the evaluation target thermoelectric element 101, and simultaneously measures the temperature of the cold junction of the evaluation target thermoelectric element 101, and the heat flow control device 115 The current of the heat flow control thermoelectric element 105 is controlled so that the measured heat flow becomes zero.
[0053]
In the state set in this way, by passing a current through the evaluation target thermoelectric element 101 and measuring the maximum temperature difference generated at both ends of the hot junction and the cold junction of the evaluation target thermoelectric element 101, It is possible to measure an accurate maximum temperature difference in a state where 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 evaluation target thermoelectric element 101 is prevented from dew condensation, and the heat entering and exiting from the side surface between the hot junction and the cold junction of the evaluation target thermoelectric element 101 is insulated. Therefore, the measurement accuracy of the maximum temperature difference is increased.
[0055]
FIG. 2 is a cross-sectional view showing typical structures of the evaluation target thermoelectric element 101, the temperature control thermoelectric element 104, and the heat flow control thermoelectric element 105 in the thermoelectric element performance evaluation apparatus of the present invention. The p-type thermoelectric semiconductor 201 and the n-type thermoelectric semiconductor 202 are arranged alternately and regularly, and are wired by wiring electrodes 203 at both ends of each thermoelectric semiconductor, and a plurality of p-type thermoelectric semiconductors and n-type thermoelectric semiconductors are arranged. Are alternately connected in series.
[0056]
The two lead electrodes 204 for connecting the lead wires for flowing 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 conducting plates 205 and 206 are bonded to each other, and one is a hot junction and the other is a cold junction. Both can be hot or cold junctions in the direction of current flow.
[0057]
For example, when the thermoelectric element is cooled by passing a current so that the heat conduction plate 205 side becomes a cold junction in FIG. 2, Joule heat generated by the amount of heat absorbed at the cold junction and the current flowing through the thermoelectric element becomes the heat that becomes the hot junction. Carry to the conductive plate 206 side. For this reason, unless the heat conduction plate 206 has a structure that can dissipate the heat, the heat accumulates and the temperature rises. As a result, the temperature on the cold junction side also rises.
[0058]
Further, when heating is performed so that the heat conduction plate 205 side becomes a hot junction, that is, when a current is passed, the heat conduction plate 206 side becomes a cold junction, and the heat conduction plate 206 side supplies necessary heat. If the temperature is not maintained at, the temperature decreases, and the temperature on the heat conduction plate 205 side to be heated also decreases due to the influence.
[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]
As the heat conductive plates 205 and 206, ceramics having good heat conductivity such as aluminum nitride and alumina are used.
[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 type and FeSi type can be used.
[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 measurement plate 103 is joined to the upper part of the temperature control thermoelectric element 104 with good heat conduction.
[0064]
The above-mentioned structural members are joined with a heat conductive adhesive, or with a heat conductive grease and fixed with screws or the like.
[0065]
The temperature measurement plate 103 embeds a temperature sensor 301 such as a thermistor or a platinum resistance temperature detector near the surface in contact with the evaluation target thermoelectric element 101, measures the temperature of the hot junction of the evaluation target thermoelectric element 101, and The signal is fed back to control the current flowing through the lead wire 302 that inputs current to the temperature adjusting thermoelectric element 104 so that the temperature of the hot junction of the evaluation target thermoelectric element 101 is kept constant.
[0066]
The structure of the temperature control thermoelectric element 104 is the same as that of the general thermoelectric element shown in FIG. 2, and a thermoelectric element that is considerably larger than the thermoelectric element 101 to be evaluated is used.
[0067]
The heat exchanger 106 has an inside of a hermetically sealed cavity, has a circulation path 303 that fills the inside with a liquid capable of carrying heat such as water, and takes in and out the liquid from the outside. Circulate to keep the temperature constant.
[0068]
In this way, the heat that enters and exits the heat exchanger 106 through 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]
A specific example of such a system is a combination of SL-10W and SL-CP1206 manufactured by Nippon Blower Co., Ltd.
[0070]
The heat exchanger 106 is 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 heat exchanger 106 and other parts that exchange heat with the outside air are 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 weighted spring 108 is joined to the lower part of the movable plate 109, a heat heat exchanger 107 is joined to the lower part of the weighted spring 108, and the heat flow control thermoelectric element 105 is thermally conducted to the lower part of the heat exchanger 107. The heat flow measuring device 102 is bonded to the lower part of the heat flow control thermoelectric element 105 with good heat conduction.
[0073]
The above-mentioned structural members are joined with a heat conductive adhesive, or with a heat conductive grease and fixed with screws or the like.
[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 a uniform thermal conductivity, has the same cross-sectional shape as the evaluation target thermoelectric element 101, and is a central portion of the cross-sectional shape and a cold junction of the evaluation target thermoelectric element 101. Two temperature sensors 501 and 502 such as a thermistor or a platinum resistance temperature detector are embedded in the vicinity of the surface in contact with and in the vicinity of the surface in contact with the heat flow control thermoelectric element 105, and the temperature sensor 501 determines the temperature of the cold junction of the evaluation target thermoelectric element 101. At the same time, the temperature sensor 502 measures the temperature near the surface in contact with the heat flow control thermoelectric element 105.
[0075]
Then, the signals from the temperature sensors 501 and 502 are fed back to control the current flowing through the lead wire 401 that inputs 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 at two points separated by a certain distance is the same in the direction perpendicular to the cross section of a member having uniform heat conductivity and uniform cross section, the cross section passes through the 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 is zero.
[0078]
At this time, if the cross-sectional shapes of the thermoelectric element 101 to be evaluated and the heat flow measuring device 102 are the same, the heat flow becomes linear and uniform, which has the effect of improving the sensitivity of the heat flow measurement.
[0079]
The structure of the heat flow control thermoelectric element 105 is the same as that of the general thermoelectric element shown in FIG. 2, and a thermoelectric element considerably larger than the evaluation target thermoelectric element 101 is used in the same manner as the temperature control 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 the 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, the variation in the parallelism of each contact surface can be absorbed by the weighted spring 108, and the heat conductivity is closely adhered. Can be made.
[0081]
Further, the weight can be arbitrarily adjusted by adjusting the length of the weight spring 108 to be contracted.
[0082]
By adopting the above structure, the heat flow of the heat flow measuring device 102 can be made 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]
In addition, although the heat flow control thermoelectric element 105 shown in FIG. 4 has a single stage, by making a structure in which two thermoelectric elements of different sizes are stacked, rough temperature control is performed with 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 is proportional to the temperature difference between the temperature sensors 501 and 502, the temperature sensor 501 is configured by configuring the heat flow measuring device 102 with a material whose heat conductivity is accurately known. , 502 can be used to calculate the heat flow.
[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 heat flow. Therefore, even if the heat flow is not controlled to zero, the evaluation can be performed based on the calculated value.
[0086]
FIG. 6 is a diagram for explaining 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. Inside the heat exchanger 106, there is a circulation path 303 for introducing and discharging constant temperature water as described above, and reacts quickly 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 from 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 temperature control thermoelectric element 104. The current control circuit 602 is connected to the power supply circuit 603 and the external outlet 604 ahead. The current control circuit 602 is connected to a console 605 in which a display unit for displaying the real-time temperature and the set temperature, a switch for changing settings, and the like are gathered. 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) 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 accurately realized.
[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 the signals of 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 the power supply circuit 703 and the external outlet 704 ahead. The current control circuit 702 is connected to a console 705 in which a display unit for displaying the real-time temperature and a temperature difference, a switch for changing settings, and the like are gathered. One control device 706 is formed.
[0091]
In the current control circuit 702, the temperature measured by the temperature sensors 501 and 502 is fed back so that the temperature measured by the temperature sensors 501 and 502 becomes the same temperature, 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 so that the heat flow passing through the heat flow measuring device 102 becomes zero, and the hot junction of the evaluation target thermoelectric element 101 is fixed to the temperature measuring plate 103. The heat inflow and outflow of the cold junction of the evaluation target thermoelectric element 101 can be made zero, and the temperature (temperature difference) between the hot junction and the cold junction of the evaluation target thermoelectric element 101 at that time is measured. Thus, the maximum temperature difference can be measured accurately and accurately.
[0093]
(Second Embodiment)
Next, the structure and evaluation method of the thermoelectric element performance evaluation apparatus 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, as the heat flow measuring device 102, 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 with good heat conduction, and the other heat flow measuring thermoelectric element 801 is heat flow controlled thermoelectric element. 105 is bonded with good thermal conductivity.
[0095]
A temperature sensor 804 such as a thermistor or a platinum resistance thermometer is embedded in the vicinity of the surface of the temperature measurement plate 803 that is not bonded to the heat flow measurement thermoelectric element 801, and evaluation is performed by closely contacting the evaluation target thermoelectric element 101 with good heat conduction. The temperature of the cold junction of the target thermoelectric element 101 is measured.
[0096]
The structural feature of the second embodiment is that the heat flow measuring device 102 is simply replaced with the structure shown in FIG. 8, and the structure of the other members is the same as that of the first embodiment.
[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 at which. That is, the heat flow passing through the heat flow measurement thermoelectric element 801 is proportional to the voltage generated by the heat flow measurement 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 is zero, the heat flow passing through the heat flow measurement thermoelectric element 801 can be zero.
[0098]
FIG. 9 is a diagram for explaining a control system of the heat flow control device 115 in the second embodiment.
[0099]
The heat flow measuring 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 measuring thermoelectric element 801. Further, the heat flow measuring device 102 is connected to a temperature conversion circuit 901 that converts a signal from 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 the power supply circuit 703 and the external outlet 704 ahead. The current control circuit 902 is connected to a console 903 in which a display unit for displaying the real-time temperature and voltage, a switch for changing settings, and the like are gathered.
[0100]
In the current control circuit 902, the heat flow measurement thermoelectric element 801 is configured 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).
[0101]
Since the heat flow measuring device 102 having the structure shown in FIG. 5 uses temperature sensors 501 and 502 such as a thermistor and a platinum resistance thermometer to measure the heat flow, a sealing material other than the detection portion of the temperature sensor, There is a possibility that the response speed for detecting the temperature is slightly slowed by the heat capacity of the coating material.
[0102]
However, in the heat flow measuring device 102 having the structure shown in FIG. 8, 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 detection part, and therefore, a wasteful heat capacity that slows the response speed. Does 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 compared to the heat flow measuring device 102 having the structure shown in FIG. .
[0103]
Further, in general, in a thermoelectric element, a value obtained by multiplying a logarithm and a temperature difference is proportional to a generated voltage. Therefore, as the logarithm of the heat flow measurement thermoelectric element 801 is increased, the detected voltage becomes larger. 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 maximum temperature difference can be measured more accurately.
[0104]
(Third embodiment)
Next, the structure and evaluation method of the thermoelectric element performance measuring apparatus according to the third embodiment of the present invention will be described with reference to FIG.
[0105]
As shown in FIG. 10, the structural feature of the third embodiment is that a heater 1001 is inserted between the thermoelectric element 101 to be evaluated and the heat flow measuring device 102. Here, by controlling the heat flow passing through the heat flow measuring device 102 to zero with the same method described in the first embodiment and the second embodiment above, by measuring the heat quantity of the heater 1001, In addition to the maximum temperature difference of the thermoelectric element 101 to be evaluated, it is possible to actually measure 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 802 of the temperature sensors 501, 502, and 804 of the heat flow meter 102 and the thermoelectric element 801, There is a slight possibility that heat will come in and out. If the thermoelectric element 101 to be evaluated and the heat flow measuring device 102 have a small size, even a slight amount of heat is affected, which may cause a large error. As a countermeasure, although not shown, by adopting a structure in which the lead wire is brought into contact with the heat flow control thermoelectric element 105, the heat entering and exiting through the lead wire can be made zero, and the evaluation of a small-sized thermoelectric element is also high. Can be done with precision.
[0107]
Further, in the first embodiment, the second embodiment, and the third embodiment, two heat exchangers 106 and 107 are used. If a large heat exchanger is used, one heat exchanger is used instead. Is also possible. In that case, the measurement margin is improved by making the heat flow control thermoelectric element 105 a two-stage thermoelectric element in order to widen the measurement range.
[0108]
【The invention's effect】
As apparent from the above description, the thermoelectric element performance evaluation apparatus of the present invention connects the heat flow measuring means to the evaluation target thermoelectric element, connects the heat flow measuring means to the heat flow control means, and uses the weighting means to change the evaluation target thermoelectric element. By pressing against the temperature adjusting means with a constant load and controlling the heat flow of the heat flow measuring means to zero by the heat flow controlling means, the thermal resistance of the contact surface between the hot junction of the thermoelectric element to be evaluated and the temperature adjusting means is made small and constant. And the inflow of heat from the outside at the cold junction of the thermoelectric element to be evaluated can be made zero. Therefore, an accurate maximum temperature difference can be measured in an ideal state where the endothermic 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, so that there is an advantage that the measurement accuracy is further improved.
[0110]
Then, by connecting the lead wire exiting from the heat flow measuring means to the heat flow control means, the heat entering and exiting the lead wire can be shut off, and even a small thermoelectric element can be measured accurately.
[0111]
Furthermore, by providing a heater between the evaluation target thermoelectric element 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 evaluation target thermoelectric element but also the maximum heat absorption amount. It becomes possible.
[0112]
As a result, the quality of the thermoelectric element can be confirmed by actually measuring it, and the thermoelectric element having the 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 apparatus 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 apparatus according to the first embodiment of the present invention.
FIG. 3 is a perspective view of a temperature adjustment 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 weighted spring, a heat flow control device, and a heat flow measuring device of the thermoelectric element performance evaluation apparatus 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 apparatus according to the first embodiment of the present invention.
FIG. 6 is a control system diagram of the temperature adjustment device of the thermoelectric element performance evaluation apparatus according to the first embodiment of the present invention.
FIG. 7 is a control system diagram of the 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 the heat flow measuring device of the thermoelectric element performance evaluation apparatus according to the second embodiment of the present invention.
FIG. 9 is a control system diagram of the 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 showing an overall configuration of a thermoelectric element performance evaluation apparatus 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 apparatus.
[Explanation of symbols]
101 Thermoelectric element to be evaluated
102 Heat flow meter
103, 803 Temperature measurement plate
104 Temperature control thermoelectric element
105 Heat Flow Control Thermoelectric Element
106,107 heat exchanger
108 Weighted spring
109 Movable plate
110 Slide member
111 Fixing member
112 Support pillar
113 base plate
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 Lead electrode
205 206 Thermal conductor
301, 501, 502, 804 Temperature sensor
302, 401 Lead wire
303, 402 circuit
601, 701, 901 Temperature conversion circuit
602, 702, 902 Current control circuit
603, 703 Power circuit
604, 704 External outlet
605, 705, 903 console
606, 706 control device
607,707 Constant temperature water circulation device
1001 Heater
1101 Thermal insulation member
1102 Weighted member

Claims

A temperature adjusting means, a heat flow measuring means, a heat flow control means, a weighting means, and an evaluation target thermoelectric element, and connecting the hot junction of the evaluation target thermoelectric element and the temperature adjustment means so as 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 and the heat flow controlling means are connected so as to be able to conduct heat, and the weighting means is used to evaluate the evaluation object. giving a load of constant connection portion between the temperature adjusting means and thermoelectric element, the heat flow thermoelectric device performance evaluation device that controls the heat flow control means so as to zero the heat flow through the measuring means.

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

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

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

The thermoelectric element performance evaluation apparatus according to any one of claims 1 to 4, wherein the thermoelectric element to be evaluated and the heat flow measuring unit are in a vacuum atmosphere.

The thermoelectric element performance evaluation apparatus 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.

A temperature adjusting means, a heat flow measuring means, a heat flow control means, a weighting means, and an evaluation target thermoelectric element, and connecting the hot junction of the evaluation target thermoelectric element and the temperature adjustment means so as 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 and the heat flow controlling means are connected so as to be able to conduct heat, and the weighting means is used to evaluate the evaluation object. A heat flow that has a structure that applies a constant load to the connection portion between the thermoelectric element and the temperature adjusting means, maintains the temperature of the hot junction of the thermoelectric element to be evaluated constant by the temperature adjusting means, and passes through the heat flow measuring means. The thermoelectric element performance evaluation method for evaluating the performance of the thermoelectric element by controlling the heat flow control means so as to make zero, and measuring two temperatures of the hot junction and the cold junction of the thermoelectric element to be evaluated.