JP2004241449A

JP2004241449A - Apparatus and method for evaluating performance of solar battery

Info

Publication number: JP2004241449A
Application number: JP2003026597A
Authority: JP
Inventors: Takeshi Yanagisawa; 武柳澤
Original assignee: National Institute of Advanced Industrial Science and Technology AIST
Current assignee: National Institute of Advanced Industrial Science and Technology AIST
Priority date: 2003-02-04
Filing date: 2003-02-04
Publication date: 2004-08-26
Anticipated expiration: 2023-02-04
Also published as: JP4625941B2

Abstract

<P>PROBLEM TO BE SOLVED: To make detectable characteristic unevenness and a local defect in an integrated type thin film solar battery. <P>SOLUTION: A stage for placing the integrated type thin film solar battery is installed in a dark box 2. A line structure light source 8 used also as a measuring electrode capable of illuminating in a line state the integrated type thin film solar battery is installed on the stage so as to realize a stepwise movement by a stepwise driver. The longitudinal direction of the line structure light source 8 is a direction for connecting in series the cells of the integrated type thin film solar battery. The line structure light source 8 is stepwisely sent from the end to the end of the photodetecting surface of the solar battery by the stepwise driver, and the current-voltage characteristics of the light illuminating part of the integrated type thin film solar battery is measured at each stopping position of the line structure light source 8. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【発明の属する技術分野】
【０００１】
本発明は、太陽電池の性能評価装置および性能評価方法に関し、特に太陽電池の局部の特性の測定を可能にし、かつ、面内の特性ばらつきを評価することのできる太陽電池の性能評価装置および性能評価方法に関するものである。
【０００２】
【従来の技術】
太陽電池は、結晶系と薄膜系とに大別される。結晶系では、ｐ型またはｎ型半導体基板（ウェハ）の表面にｎ型またはｐ型拡散層を形成し、基板表裏面に表面側電極と裏面電極とを形成することによって作製される。また、薄膜系太陽電池は、絶縁性基板上に裏面電極を形成しその上に、または、金属（ステンレス）基板上にｐ（またはｎ）型半導体層とｎ（またはｐ）型半導体層を成長させ、その上に表面電極を形成することによって作製される。
太陽電池ウェハは近年大面積化が図られているが、大面積化によって、均一な拡散や成膜が難しくなり、特性の面内均一化の維持が重要な課題となっている。また、膜厚および組成の不均一部分、ピンホール等が性能低下、経時的不安定要因になり易い。そこで、面内での拡散状況や成膜状態とそのばらつき程度を把握できるようにすることが求められている。
上記のようにして作製された太陽電池についての品質を評価する従来の方法は、電池全面に光を当て、発電性能を二端子から測定することによってなされ、平均性能として評価される。従って、従来の測定方法では電池内の局部の性能や面内での特性ばらつき程度を評価することはできない。しかし、太陽電池の局部情報を得たいというニーズは高く、これに対応して太陽電池受光面にレーザビームなどの光ビームを照射し電池面内の光電流分布を評価するレーザ光励起電流像（ＬＢＩＣ：ｌａｓｅｒｂｅａｍｉｎｄｕｃｅｄｃｕｒｒｅｎｔ）法が開発され（例えば、非特許文献１参照）、測定器もすでに市販されている。この方法は、太陽電極に二端子を取り付けた後に光ビーム照射して二端子を利用して回路短絡電流の面分布を測定するものである。
【０００３】
【非特許文献１】
ＳｃｏｔｔＡ．ＭｃＨｕｇｏｅｔａｌ．，Ａｐｐｌ．Ｐｈｙｓ．Ｌｅｔｔ．，Ｖｏｌ．７２，Ｎｏ．２６，２９Ｊｕｎｅ１９９８，ｐｐ．３４８２−３４８４
【０００４】
【発明が解決しようとする課題】
太陽電池の特性を評価する指標には、回路短絡電流（Ｉｓｃ）のみならず、回路開放電圧（Ｖｏｃ）、曲線因子（ＦＦ）、出力電力特性（Ｐ）、最大出力（Ｐｍａｘ）があり、これらの値およびそのばらつき（面内およびウェハ間）を知ることは、製品評価、工程管理の面で重要であるにも拘らず、上述したＬＢＩＣ法は回路短絡電流のみしか得られないため、新しい測定・評価方法が求められてきた。
本願発明の課題は、上述した従来技術の不備を解決することであって、その目的は、回路短絡電流のみならず、回路開放電圧、曲線因子、出力電力特性、最大出力等の局部値を知ることができるようにすることであり、これにより太陽電池の面内ばらつき、欠陥位置などの工程管理や経時的安定性について必要な情報を得ることができるようにしようとするものである。
【０００５】
【課題を解決するための手段】
上記の目的を達成するため、本発明によれば、スポット光照射手段と、前記スポット光照射手段を囲み先端部が太陽電池の光照射面と接触することができる第１の電極部とを有する第１の接触部材と、前記第１の電極部と同等の外形形状を有し概第１の電極部と対向して配備されその先端部が太陽電池の裏面側のスポット光の外周部と接触することのできる第２の電極部を有する第２の接触部材と、太陽電池を保持する太陽電池保持部材と、前記第１および前記第２の電源と接続されてスポット光下の太陽電池の回路短絡電流または回路開放電圧または電流−電圧特性を測定する測定部と、を有する太陽電池の性能評価装置、が提供される。
【０００６】
また、上記の目的を達成するため、本発明によれば、スポット光照射手段と、前記スポット光照射手段を囲み先端部が太陽電池の光照射面と接触することができる第１の電極部とを有する第１の接触部材と、太陽電池の裏面側または太陽電池の裏面電極と接触することのできる第２の電極部と、太陽電池を保持する太陽電池保持部材と、前記第１および前記第２の電源と接続されてスポット光下の太陽電池の回路短絡電流または回路開放電圧または電流−電圧特性を測定する測定部と、を有する太陽電池の性能評価装置、が提供される。
【０００７】
また、上記の目的を達成するため、本発明によれば、太陽電池の光照射面にスポット光を照射し、そのスポット光の外周部に電極を接触させスポット光下の太陽電池の回路短絡電流または回路開放電圧または電流−電圧特性を測定することを特徴とする太陽電池の性能評価方法、が提供される。
【０００８】
【発明の実施の形態】
次に、本発明の実施の形態について図面を参照して詳細に説明する。
図１は、本発明の第１の実施の形態を示す斜視図である。図１において、１は、太陽電池である被測定ウェハ、２は、装置本体が収容される遮光された暗ボックス、３はベース、４は、被測定ウェハを搬入・搬出するウェハ搬送台、５は、ウェハ搬送台４のガイドとなるガイドレール、６は、被測定ウェハ１を把持してＸ方向およびＹ方向に移動可能なウェハ保持手段、７は、ウェハ保持手段６のガイドとなる保持手段ガイド、８は、被測定ウェハ１に光を照射するとともにこれと接触して測定端子となる光源兼用測定電極、９は、被測定ウェハ１に裏面側から接触して測定端子となる対向測定電極、１０、１１は、それぞれ光源兼用測定電極８、対向測定電極９を保持して上下動する電極保持手段、１２は、電極保持手段１０、１１を駆動する測定電極駆動手段である。また、１３は、装置全体の動作をコントロールする制御部、１４は、暗ボックス内の雰囲気（温度、湿度）を調整する空調部である。
【０００９】
次に、図１に示される装置の概略の動作について説明する。被測定ウェハ１は、ウェハ搬送台４に載せられて暗ボックス２内に搬送されてくる。このとき、ウェハ保持手段６は、紙面手前側下方に位置している。ウェハ搬送台４が所定の位置に到着するとプッシャ（図示なし）が動作して被測定ウェハ１をウェハ保持手段６上に載置させる。ウェハ保持手段６は、被測定ウェハ１を把持して上昇した後水平方向に移動して、被測定ウェハ１の最初の測定点を測定電極８、９間に位置させる。このとき光源兼用測定電極８の光源は点灯状態にある。
【００１０】
図２は、このときの状態を示す斜視図である。被測定ウェハ１の位置決めが完了すると、光源兼用測定電極８が降下し、対向測定電極９が上昇して被測定ウェハ１を両電極間に挟み込む。そして、図中Ａにて示す、光照射スポット領域（電極接触部）の一つ（この場合は図の奥側左端のスポット領域）についての光−電気特性を測定する。すなわち、回路短絡電流、回路開放電圧、電流−電圧特性を測定する。ここで、被測定ウェハの裏面側には高不純物濃度拡散層または裏面電極が形成されているが、表面側には透明電極は形成されていなくてもよい。第１スポットについての測定が完了すると、光源兼用測定電極８が上昇、対向測定電極９が降下し、被測定ウェハ１が１ステップ矢印Ｂ方向に送られて被測定ウェハ１の次の光照射スポット領域Ａが測定電極８下に送られる。そして、そのスポット領域についての測定が行われる。以下同様にして、被測定ウェハ１が１ステップずつ矢印Ｂ方向に送られて各スポット領域ごと測定が行われる．Ｘ方向の１行分の測定が完了すると、被測定ウェハ１は矢印Ｃ方向に１ステップ送られる。そして、第２行目のスポット領域についての測定が順次行われる。このとき、被測定ウェハ１は矢印Ｂと反対方向に１ステップずつ送られる。このようにして、被測定ウェハ１の全面に渡る測定が行われる。なお、光照射スポット領域Ａは互いに接するようにするのが原則であるが、隣接する領域間に重複部が存在していてもよい。また、隣接する光照射スポット領域Ａ同士が乖離していてもよい（すなわち、測定が飛び飛びの領域について行われるようにしてもよい）。
図１に戻り、被測定ウェハ１について全領域の測定が完了すると、被測定ウェハ１は、ウェハ保持手段６に把持された状態でまず図の手前側に送られ次いで下方に搬送される。次に、ウェハ保持手段６による保持が解除され、プッシャ（図示なし）により、押圧されてウェハ搬送台上へ移される。そして、暗ボックス２外へ搬出される。
【００１１】
図３（ａ）、（ｂ）は、光源兼用測定電極８の底面図と断面図である。図３において、８１は、電極保持手段１０に把持される固定部、８２は、固定部８１から下方に延びる、四重に形成された絶縁材からなる絶縁円筒部、８３は、円筒状の電圧測定電極、８４は、円筒状の電流測定電極、８５は、ゴムなどの弾性絶縁材からなる絶縁リング、８６は、単色ＬＥＤまたは白色ＬＥＤである光源、８７は、絶縁円筒間に装着された、光源兼用測定電極８が被測定ウェハに接触した際に、電圧測定電極８３、電流測定電極８４、絶縁リング８５を下方へ押圧するばねである。電圧測定電極８３の内径は０．５〜５０ｍｍの範囲に設定される。
絶縁リング８５は、必ずしも設ける必要はなく省略可能である。この実施の形態では、光源兼用測定電極８内にＬＥＤを内蔵していたがこの構成に代え測定電極８の中空部に光ファイバを保持させ、任意点に配置された光源の光を光ファイバを介して被測定ウェハ上へ導くようにしてもよい。また、この実施の形態では、光源兼用測定電極８は円筒形状をしていたが、四角筒形状あるいは六角筒形状とすることもできる。
対向測定電極９は、光源兼用測定電極８から光源８６を除去した構成を有するものである。光源８６を除去した部分は、中空のままでもよいが充填物が充填されていてもよい。
【００１２】
図４は、図１に示される制御部１３の概略の構成を示すブロック図である。図４に示されるように、制御部１３には、中央処理部１３１を中心として、ウェハ搬入・搬出部１３２、ウェハ駆動部１３３、光源制御部１３４、測定電極駆動部１３５、測定部１３６、演算部１３７、判定・選別部１３８、記録部１３９が設けられる。ウェハ搬入・搬出部１３２は、中央処理部１３１の指示を受け、被測定ウェハの搬入・搬出およびその初期位置を制御する。ウェハ駆動部１３３は、被測定ウェハのＸ方向およびＹ方向のステップ送りを制御する。光源制御部１３４は、光源のオン・オフおよびその輝度を制御する。測定電極駆動部１３５は、測定電極の上下動を制御する。測定部１３６は、中央処理部１３１より被測定ウェハの測定スポットに測定電極が接触したことの信号を受けると被測定ウェハの１光照射スポット領域のＩ−Ｖ特性を測定する。中央処理部１３１は、測定部１３４より１スポット領域のＩ−Ｖ特性の測定が完了したことを示す信号を受け取ると測定電極駆動部１３５、演算部１３７へ向けてトリガー信号を発信する。演算部１３７は、測定部１３６の測定データを受け取りこれに基づいて最大出力ＰｍａｘとＦＦ値とを算出する。測定部１３６の測定データと演算部１３７の演算結果とは、判定・選別部１３８と記録部１３９とに伝達される。判定・選別部１３８は、被測定太陽電池の全面のデータを取得すると、その被測定太陽電池の良・不良の判別および不良発生個所の特定を行うと共に不良品が発生した場合には警告を発し、良品である場合にはその光−電気特性に応じてクラス分けを行う。警告が発せられると製造ラインへフィードバックがかけられる。
【００１３】
図５は、図１〜図４に示される本実施の形態に係る太陽電池の測定装置を用いた処理の流れの一例を示すフローチャートである。この例では、光源は１ウェハの全スポット領域を測定する間常時点灯されているものとされる。また、ウェハのステップ送り回数はＸ方向にＮ、Ｙ方向にＭ（測定されるスポット領域はＸ方向にＮ＋１、Ｙ方向にＭ＋１）であるものとする。太陽電池処理部Ａでは、ステップＳ１０１において、被測定ウェハが測定電極間に送られてきて位置決めされる。ステップＳ１０２において、ｍ＝０と設定され、ステップＳ１０３において、ｎ＝０と設定される。そして、ステップＳ１０４において、測定電極が被測定ウェハに接触し光−電気特性の測定が行われる。すなわち、光の照射されたスポット領域の電流−電圧特性が測定される。この測定が完了すると、ステップＳ１０５において、トリガー信号が発信され、測定電極が被測定ウェハから離れる。そして、ステップＳ１０６において、ｎがＮであるか否かがチェックされる。ｎがＮである場合には、ステップＳ１０７に至り、ｍがＭであるか否かがチェックされる。ｍがＭである場合には、ステップＳ１０８において、被測定ウェハは測定位置から外され、本装置外へ搬出される。
【００１４】
ステップＳ１０６において、ｎ＝Ｎではないと判定された場合には、ステップＳ１０９に至り、ｍが偶数であるか否かがチェックされる。ｍが偶数である場合には、ステップＳ１１０において、被測定ウェハはＸ方向に１ステップ送られ、ステップＳ１１１に至る。ステップＳ１０９において、ｍが偶数でないと判定された場合には、ステップＳ１１２において、被測定ウェハは−Ｘ方向に１ステップ送られ、ステップＳ１１１に至る。ステップＳ１１１において、ｎ＝ｎ＋１とした後、ステップＳ１０４へ戻る。
ステップＳ１０７において、ｍ＝Ｍではないと判定された場合には、ステップＳ１１３に至り、被測定ウェハをＹ方向に１ステップ送り、ステップＳ１１４において、ｍ＝ｍ＋１とした後、ステップＳ１０３へ戻る。
【００１５】
データ処理部Ｂでは、ウェハ処理部ＡのステップＳ１０１において、被測定ウェハの搬入が行われると、ステップＳ２０１において、ｐ＝０と設定し、ステップＳ２０２において、ｑ＝０と設定した後、ウェハ処理部Ａより、トリガー信号が発信されるのを待つ。ステップＳ２０３において、ウェハ処理部ＡのステップＳ１０５にて発信されたトリガー信号が受信されると、ステップＳ２０４に移り、ウェハ処理部ＡのステップＳ１０４にて得られた測定データを取り込む。そして、ステップＳ２０５において、取得した測定データに基づいて最大出力Ｐｍａｘを求め、ＦＦ値を算出する。次いで、ステップＳ２０６において、ｑがＮであるか否かがチェックされ、ｑがＮである場合には、ステップＳ２０７へ移り、ｐがＭであるか否かがチェックされ、ｐがＭである場合には、ステップＳ２０８において、測定の終了した被測定ウェハの測定結果、演算結果を取得して、当該被測定ウェハについて判定・選別を行う。すなわち、不良品は除外され、良品は特性に応じてクラス分けされる。不良品が発生した場合には、製造ラインに対してフィードバックが行われる（ステップＳ２０９）。
【００１６】
ステップＳ２０６において、ｑがＮではないと判定された場合には、ステップＳ２１０に移り、ｑ＝ｑ＋１とした後、トリガー信号の発信を待ち、ステップＳ２０３へ進む。
ステップＳ２０７において、ｐがＭではないと判定された場合には、ステップＳ２１１に移り、ｑ＝ｑ＋１とした後、ステップＳ２０２へ戻る。
【００１７】
上述した第１の実施の形態は、被測定ウェハ１をＸ−Ｙ方向へステップ移動させるものであったが、測定電極駆動手段１２をＸ−Ｙ平面上をステップ移動させることにより、測定電極８、９をＸ−Ｙ方向にステップ移動させるようにしてもよい。あるいは、被測定ウェハ１を例えばＸ方向へのみステップ移動させ測定電極８、９をＹ方向にステップ移動させるようにして、被測定ウェハと測定電極の双方をステップ移動させるようにしてもよい。
【００１８】
図６は、本発明の第２の実施の形態を示す要部斜視図である。図６において、図１に示した第１の実施の形態の部分と同等の機能を有する部材には同一の参照番号が付せられている。本実施の形態のおいては、被測定ウェハ１は、ＹおよびＺ方向に移動可能なウェハ保持手段６により垂直に保持される。また、光源兼用測定電極８を保持する電極保持手段１０と対向測定電極９を保持する電極保持手段１１とは、測定電極駆動手段１２により、左右方向に移動される。
本実施の形態の装置も第１の実施の形態装置と同様に動作し、第１の実施の形態装置と同様の効果を奏することができる。本実施の形態においても、測定電極側をＹおよびＺ方向にステップ移動可能に変更することも、測定電極と被測定ウェハの一方をＹ方向へステップ移動させ他方をＺ方向へステップ移動させるように変更することも可能である。
【００１９】
図７は、本発明の第３の実施の形態を示す斜視図である。図７において、図１に示した第１の実施の形態の部分と同等の機能を有する部材には同一の参照番号が付せられている。本実施の形態のおいては、被測定ウェハ１は、Ｙ方向およびＸ方向へステップ移動するＹ−Ｘテーブル１５上に固定される対向測定電極ステージ１６上に載置される。被測定ウェハ１と対向測定電極ステージ１６との間には、板状ないしマット状の対向測定電極（図示なし）が配置されており、被測定ウェハ１の裏面に形成された高不純物濃度層または裏面電極と接触している。光源兼用測定電極８は、電極保持手段１０により上下動されて、対向測定電極との間に被測定ウェハ１を挟み込んで測定を行う。
本実施の形態の装置においても、被測定ウェハを固定し測定電極側をＸおよびＹ方向にステップ移動できるようにしてもよい。また、測定電極と被測定ウェハの双方をステップ移動させるようにすることも可能である。
対向測定電極は以下のように変更することが可能である。すなわち、ポゴピンのように弾性的に接触することのできるピンを対向測定電極ステージ１６に複数本林立させて対向測定電極とする。以上は、被測定ウェハの全面に対向測定電極を接触させるものであったが、ウェハ裏面に裏面電極が形成されている場合や金属基板を用いた場合には、その裏面電極や金属基板と部分的に接触する対向測定電極を用いることができる。また、薄膜系太陽電池の場合には、基板上に形成された裏面電極の露出部と弾性的に接触するクリップ電極を対向測定電極とすることができる。
【００２０】
図８は、本発明の第４の実施の形態を示す要部斜視図である。本実施の形態の図１に示した第１の実施の形態と異なる点は、第１の実施の形態においては、光源兼用測定電極８と対向測定電極９とを１本ずつ設け、一光照射スポットごとに測定を行っているのに対し、本実施の形態においては、光源兼用測定電極８と対向測定電極９とはライン状に４本設けられている。そして、本実施の形態においては、四光照射スポットに対し一括して測定を行う。本実施の形態に拠れば、測定・評価の時間を短縮することができる。
【００２１】
図９は、本発明の第５の実施の形態を示す要部斜視図である。本実施の形態の図８に示した第４の実施の形態と異なる点は、第４の実施の形態においては、光源兼用測定電極８と対向測定電極９とが１列にライン状に連続して配置されていたのに対し、本実施の形態においては、光源兼用測定電極８と対向測定電極９とは２列に、かつ、各測定電極はＸ方向およびＹ方向に一光照射スポット分の間隔を隔てて配置されている点である。第４の実施の形態の場合のように、光源兼用測定電極８を連続して設けた場合には隣接光照射スポット間での干渉により測定精度が低下する恐れがあるので、本実施の形態のように各測定電極間を離すことが望ましい。本実施の形態においては、Ｘ方向およびＹ方向に１ステップ移動させた後には３ステップ移動させる必要がある。
【００２２】
図１０（ａ）は、本発明の第６の実施の形態を示す要部斜視図であり、図１０（ｂ）は、その要部平面図である。図８に示した第４の実施の形態では、光源兼用測定電極８、対向測定電極９がライン状に配置されていたが、本実施の形態においては、被測定ウェハ１の受光領域の全面をカバーできるように、マトリックス状に配置される。そして、光源兼用測定電極８と対向測定電極９とは、それぞれ上下動可能な箱型の電極保持手段１０、１１に保持されている。また、第４、第５の実施の形態では、測定は複数スポットに対して同時に行われていたが、本実施の形態においては、１スポットずつ行なわれる。すなわち、光源用電源１７および測定器１８が、走査回路１９を介して光源兼用測定電極８と対向測定電極９に順次接続され、光源の点灯とその光照射スポット領域の測定が順次行なわれる。
【００２３】
次に、本実施の形態の動作について説明する。被測定ウェハ１が、搬送手段（図示なし）により、図１０（ａ）に示されるように、電極保持手段１０、１１間に搬送されてきて位置決めされる。次に、電極保持手段１０、１１が駆動手段（図示なし）によりそれぞれ上昇、降下せしめられ、被測定ウェハ１が測定電極８、９間に挟持される。最初に、例えば、図１０（ｂ）の最上段左端の光源兼用測定電極８とその光源が走査回路１９を介して測定器１８、光源用電源１７に接続され、またその測定電極８に対向する位置にある対向測定電極９が走査回路１９を介して測定器１８に接続され、その位置の光源が点灯され、そのスポット領域の測定が行われる。第１のスポット領域の測定が完了すると、走査回路１９は、光源用電源１７、測定器１８の接続を最上段左端の右隣に位置する光源兼用測定電極８に切り換え、またその光源兼用測定電極８に対向する位置にある対向測定電極９に測定器１８が接続されて、第２のスポット領域の測定が行われる。以下同様にして、走査回路１９により、光源用電源１７、測定器１８の測定電極８、９への接続が順次切り換えられ、測定が繰り返される。被測定ウェハ１の受光領域全体の測定が完了すると、すなわち、すべての光源兼用測定電極８と対向測定電極９に対する走査回路１９による走査が完了すると、電極保持手段１０、１１が駆動手段（図示なし）によりそれぞれ降下、上昇せしめられ、被測定ウェハ１が搬送手段（図示なし）により、外部へ搬出される。
被測定ウェハ１の裏面に高不純物濃度層または裏面電極が形成されているとき、マトリックス状に配置された複数の対向測定電極を用いるのに代え、１枚の板状ないしマット状の対向測定電極を用いることができる。あるいは、ポゴピンのような弾性的に接触することのできるピンを林立させて対向測定電極とすることもできる。また、薄膜系太陽電池の場合には、基板上に形成された裏面電極の露出部と弾性的に接触する電極を対向測定電極とすることができる。
【００２４】
【実施例】
ガラス基板上にＭｏ裏面電極が形成された受光面が３６ｍｍ×２７ｍｍのＣＩＧＳ太陽電池を、図７に示す装置を用い、裏面電極をクリップ電極で挟んで回路短絡電流Ｉｓｃ、回路開放電圧ＶｏｃおよびＩ−Ｖ特性の測定を行った。スポット光径は３ｍｍで、Ｘ−Ｙ方向のステップ移動幅は３ｍｍであり、測定スポット数は１０８である。
測定結果を相対値にて図１１〜図１４に示す。図１１、図１２、図１３、図１４は、それぞれ回路短絡電流Ｉｓｃ、回路開放電圧Ｖｏｃ、最大出力電力Ｐｍａｘ、曲線因子ＦＦを示す図であって、各図の最上段は、Ｙ＝一定としてＸ方向に１２スポット測定した結果を示す折れ線グラフを９本集めたものであり、各図において、異なる折れ線グラフはそれぞれＹ方向位置の異なる位置での測定結果を示している。また、各図の中段は、最上段に示すデータを基に作成した面内分布を示すグラフである。
各図の上段の図より、面内のデータのばらつき程度が判定できる。たとえば、Ｐｍａｘの分布では面内において３％のばらつき幅があることが分かる。合否判定基準は分布の幅と製品の要求品質レベル等に基づいて設定し、合否判定する。不合格となった場合、不合格の主要因である評価パラメータおよび他の評価パラメータの解析から改善案情報を作成することができ、これを製造過程にフィードバックすることができる。また、各図の中段の図から、電池受光面の異常の位置および広がりを把握できる。
【００２５】
【発明の効果】
以上説明したように、本発明は、太陽電池受光面にスポット光を照射しスポット光照射部外周に測定電極を当接させて太陽電池の光−電気特性を測定するものであるので、太陽電池の局部的諸特性を測定することが可能になり、性能の内部均一性を評価することが可能になる。したがって、本発明によれば、太陽電池内部の局部劣化および異常の診断が可能になり、その情報を製造過程へフィードバックすることにより欠陥要素の除去された、経時変化の起こりにくい高品質の製品の供給が可能になる。
【図面の簡単な説明】
【図１】本発明の第１の実施の形態の概略の斜視図。
【図２】本発明の第１の実施の形態の要部斜視図。
【図３】本発明の評価装置において用いられる光源兼用測定電極の一例を示す底面図と断面図。
【図４】本発明の第１の実施の形態における制御部のブロック図。
【図５】本発明の第１の実施の形態における動作を示すフローチャート。
【図６】本発明の第２の実施の形態の要部斜視図。
【図７】本発明の第３の実施の形態の斜視図。
【図８】本発明の第４の実施の形態の要部斜視図。
【図９】本発明の第５の実施の形態の要部斜視図。
【図１０】本発明の第６の実施の形態の要部斜視図と要部平面図。
【図１１】本発明の一実施例でのＣＩＧＳ太陽電池回路短絡電流Ｉｓｃの面内スポット測定結果を示す折れ線グラフと相対面分布図。
【図１２】本発明の一実施例でのＣＩＧＳ太陽電池回路開放電圧Ｖｏｃの面内スポット測定結果を示す折れ線グラフと相対面分布図。
【図１３】本発明の一実施例でのＣＩＧＳ太陽電池最大出力電力Ｐｍａｘの面内スポット測定結果を示す折れ線グラフと相対面分布図。
【図１４】本発明の一実施例でのＣＩＧＳ太陽電池曲線因子ＦＦの面内スポット測定結果を示す折れ線グラフと相対面分布図。
【符号の説明】
１被測定ウェハ
２暗ボックス
３ベース
４ウェハ搬送台
５ガイドレール
６ウェハ保持手段
７保持手段ガイド
８光源兼用測定電極
８１固定部
８２絶縁円筒部
８３電圧測定電極
８４電流測定電極
８５絶縁リング
８６光源
８７ばね
９対向測定電極
１０、１１電極保持手段
１２測定電極駆動手段
１３制御部
１４空調部
１５Ｘ−Ｙテーブル
１６対向測定電極ステージTECHNICAL FIELD OF THE INVENTION
[0001]
The present invention relates to a solar cell performance evaluation device and a performance evaluation method, and more particularly to a solar cell performance evaluation device and performance capable of measuring local characteristics of a solar cell and capable of evaluating in-plane characteristic variations. It concerns the evaluation method.
[0002]
[Prior art]
Solar cells are broadly divided into crystalline and thin-film cells. In the case of a crystal system, an n-type or p-type diffusion layer is formed on the surface of a p-type or n-type semiconductor substrate (wafer), and a front-side electrode and a back-side electrode are formed on the front and back surfaces of the substrate. In a thin-film solar cell, a back electrode is formed on an insulating substrate, and a p (or n) type semiconductor layer and an n (or p) type semiconductor layer are grown thereon or on a metal (stainless) substrate. And a surface electrode is formed thereon.
In recent years, solar cell wafers have been increased in area, but with the increase in area, uniform diffusion and film formation have become difficult, and maintaining in-plane uniformity of characteristics has become an important issue. In addition, uneven portions and pinholes in the film thickness and composition are likely to cause performance degradation and temporal instability. Therefore, it is required to be able to grasp the state of diffusion and the state of film formation in the plane and the degree of variation thereof.
A conventional method for evaluating the quality of the solar cell manufactured as described above is performed by irradiating light to the entire surface of the cell and measuring the power generation performance from two terminals, and is evaluated as an average performance. Therefore, the conventional measurement method cannot evaluate the performance of a local part in a battery or the degree of characteristic variation in a plane. However, there is a high need to obtain local information of the solar cell, and in response to this, a laser beam excitation current image (LBIC) is used to irradiate a light beam such as a laser beam to the solar cell light receiving surface and evaluate the photocurrent distribution in the cell surface. : Laser beam induced current) method has been developed (for example, see Non-Patent Document 1), and measuring instruments are already commercially available. In this method, a light beam is irradiated after attaching two terminals to the solar electrode, and the surface distribution of the short circuit current is measured using the two terminals.
[0003]
[Non-patent document 1]
Scott A. McHugo et al. , Appl. Phys. Lett. , Vol. 72, No. 26, 29 June 1998, pp. 30-29. 3482-3484
[0004]
[Problems to be solved by the invention]
Indices for evaluating the characteristics of the solar cell include not only the circuit short-circuit current (Isc) but also the circuit open-circuit voltage (Voc), the fill factor (FF), the output power characteristic (P), and the maximum output (Pmax). Is important in product evaluation and process control, it is important to know the value of and its variance (in-plane and between wafers).・ Evaluation methods have been required.
An object of the present invention is to solve the above-mentioned deficiencies of the prior art. The purpose of the present invention is to know not only a short circuit current but also local values such as an open circuit voltage, a fill factor, an output power characteristic, and a maximum output. It is intended to obtain necessary information on process control such as in-plane variation of a solar cell and a defect position and stability over time.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, there is provided a spot light irradiating unit, and a first electrode unit which surrounds the spot light irradiating unit and whose leading end can contact a light irradiating surface of a solar cell. A first contact member, which has an outer shape equivalent to that of the first electrode portion, is provided so as to substantially face the first electrode portion, and has a tip portion in contact with an outer peripheral portion of spot light on the back surface side of the solar cell; A second contact member having a second electrode portion capable of being operated, a solar cell holding member for holding a solar cell, and a circuit of a solar cell under a spotlight connected to the first and second power sources A performance evaluation device for a solar cell, comprising: a measurement unit configured to measure a short-circuit current, an open circuit voltage, or a current-voltage characteristic.
[0006]
In order to achieve the above object, according to the present invention, a spot light irradiating unit, and a first electrode unit which surrounds the spot light irradiating unit and whose leading end can contact a light irradiating surface of a solar cell. A first contact member having: a second electrode portion capable of contacting the back surface side of the solar cell or the back surface electrode of the solar cell; a solar cell holding member holding the solar cell; And a measuring unit connected to the second power supply and measuring a short circuit current or an open circuit voltage or a current-voltage characteristic of the solar cell under the spotlight.
[0007]
Further, in order to achieve the above object, according to the present invention, a light irradiation surface of a solar cell is irradiated with a spot light, and an electrode is brought into contact with an outer peripheral portion of the spot light to cause a short circuit current of the solar cell under the spot light. Alternatively, there is provided a method for evaluating the performance of a solar cell, comprising measuring a circuit open-circuit voltage or a current-voltage characteristic.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a perspective view showing a first embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a wafer to be measured which is a solar cell, 2 denotes a light-shielded dark box in which an apparatus main body is housed, 3 denotes a base, 4 denotes a wafer carrier for loading / unloading the wafer to be measured, 5 Is a guide rail serving as a guide for the wafer transfer table 4; 6 is a wafer holding means capable of gripping the wafer 1 to be measured and moving in the X and Y directions; 7 is a holding means serving as a guide for the wafer holding means 6 A guide 8 irradiates the wafer 1 to be measured with light and makes contact with the light source and also serves as a measurement terminal. A counter electrode 8 comes in contact with the wafer 1 to be measured from the back side and becomes a measurement terminal. Reference numerals 10 and 11 denote electrode holding means for holding the measurement electrode 8 serving as a light source and the counter measurement electrode 9 and moving up and down, and reference numeral 12 denotes a measurement electrode driving means for driving the electrode holding means 10 and 11. Reference numeral 13 denotes a control unit that controls the operation of the entire apparatus, and reference numeral 14 denotes an air conditioning unit that adjusts the atmosphere (temperature and humidity) in the dark box.
[0009]
Next, a schematic operation of the apparatus shown in FIG. 1 will be described. The wafer 1 to be measured is placed on the wafer carrier 4 and carried into the dark box 2. At this time, the wafer holding means 6 is located below the front side of the drawing. When the wafer carrier 4 arrives at a predetermined position, a pusher (not shown) operates to place the wafer 1 to be measured on the wafer holding means 6. The wafer holding means 6 grips and rises the wafer 1 to be measured and moves in the horizontal direction to position the first measurement point of the wafer 1 to be measured between the measurement electrodes 8 and 9. At this time, the light source of the light source / measuring electrode 8 is in a lighting state.
[0010]
FIG. 2 is a perspective view showing the state at this time. When the positioning of the wafer 1 to be measured is completed, the measurement electrode 8 also serves as a light source, and the opposing measurement electrode 9 rises to sandwich the wafer 1 to be measured between the two electrodes. Then, the photo-electric characteristic of one of the light irradiation spot areas (electrode contact portions) (in this case, the spot area at the left end on the far side in the figure) indicated by A in the figure is measured. That is, the circuit short circuit current, circuit open voltage, and current-voltage characteristics are measured. Here, the high impurity concentration diffusion layer or the back electrode is formed on the back side of the wafer to be measured, but the transparent electrode may not be formed on the front side. When the measurement of the first spot is completed, the measurement electrode 8 also serves as a light source, the counter measurement electrode 9 descends, and the wafer 1 to be measured is sent in the direction of the arrow B for one step. The area A is sent below the measurement electrode 8. Then, the measurement for the spot area is performed. Similarly, the wafer 1 to be measured is sent one step at a time in the direction of arrow B, and the measurement is performed for each spot area. When the measurement for one row in the X direction is completed, the wafer under test 1 is moved one step in the direction of arrow C. Then, the measurement of the spot area on the second row is sequentially performed. At this time, the wafer 1 to be measured is sent one step at a time in the direction opposite to the arrow B. In this way, the measurement over the entire surface of the wafer 1 to be measured is performed. Note that the light irradiation spot areas A are basically in contact with each other, but overlapping portions may exist between adjacent areas. In addition, the adjacent light irradiation spot areas A may be separated from each other (that is, the measurement may be performed on intermittent areas).
Referring back to FIG. 1, when the measurement of the entire area of the wafer 1 to be measured is completed, the wafer 1 to be measured is first sent to the near side of the drawing while being held by the wafer holding means 6 and then transferred downward. Next, the holding by the wafer holding means 6 is released, and the wafer is pressed by a pusher (not shown) and transferred onto the wafer carrier. Then, it is carried out of the dark box 2.
[0011]
3A and 3B are a bottom view and a cross-sectional view of the measurement electrode 8 also serving as a light source. In FIG. 3, reference numeral 81 denotes a fixed portion gripped by the electrode holding means 10, 82 denotes an insulating cylindrical portion extending downward from the fixed portion 81 and made of a quadruple insulating material, and 83 denotes a cylindrical voltage. The measuring electrode, 84 is a cylindrical current measuring electrode, 85 is an insulating ring made of an elastic insulating material such as rubber, 86 is a light source that is a monochromatic LED or a white LED, 87 is mounted between insulating cylinders, A spring that presses the voltage measurement electrode 83, the current measurement electrode 84, and the insulating ring 85 downward when the light source / measurement electrode 8 contacts the wafer to be measured. The inner diameter of the voltage measuring electrode 83 is set in the range of 0.5 to 50 mm.
The insulating ring 85 need not always be provided, and can be omitted. In this embodiment, an LED is built in the light source / measurement electrode 8. However, instead of this configuration, the optical fiber is held in the hollow portion of the measurement electrode 8, and the light of the light source arranged at an arbitrary point is transmitted to the optical fiber. Alternatively, it may be guided to the wafer to be measured via the measurement target. Further, in this embodiment, the light source / measuring electrode 8 has a cylindrical shape, but may have a rectangular cylindrical shape or a hexagonal cylindrical shape.
The counter measurement electrode 9 has a configuration in which the light source 86 is removed from the light source / measurement electrode 8. The portion from which the light source 86 has been removed may remain hollow, but may be filled with a filler.
[0012]
FIG. 4 is a block diagram showing a schematic configuration of the control unit 13 shown in FIG. As shown in FIG. 4, the control unit 13 includes a central processing unit 131 as a center, a wafer loading / unloading unit 132, a wafer driving unit 133, a light source control unit 134, a measurement electrode driving unit 135, a measurement unit 136, an arithmetic unit. A unit 137, a determination / selection unit 138, and a recording unit 139 are provided. The wafer loading / unloading unit 132 receives instructions from the central processing unit 131 and controls loading / unloading of the wafer to be measured and its initial position. The wafer driving unit 133 controls the step feed of the wafer to be measured in the X and Y directions. The light source control unit 134 controls on / off of the light source and its brightness. The measurement electrode driving unit 135 controls the vertical movement of the measurement electrode. Upon receiving a signal from the central processing unit 131 indicating that the measurement electrode has come into contact with the measurement spot on the measurement target wafer, the measurement unit 136 measures the IV characteristics of the one light irradiation spot area of the measurement target wafer. When the central processing unit 131 receives a signal indicating that the measurement of the IV characteristic of one spot area is completed from the measurement unit 134, the central processing unit 131 transmits a trigger signal to the measurement electrode driving unit 135 and the calculation unit 137. The calculation unit 137 receives the measurement data of the measurement unit 136 and calculates the maximum output Pmax and the FF value based on the measurement data. The measurement data of the measurement unit 136 and the calculation result of the calculation unit 137 are transmitted to the determination / selection unit 138 and the recording unit 139. Upon acquiring the data of the entire surface of the measured solar cell, the determination / selection unit 138 determines whether the measured solar cell is good or defective, specifies the location where the failure has occurred, and issues a warning when a defective product occurs. If they are non-defective, they are classified according to their optical-electrical characteristics. When a warning is issued, feedback is given to the production line.
[0013]
FIG. 5 is a flowchart illustrating an example of a flow of processing using the solar cell measurement device according to the present embodiment illustrated in FIGS. 1 to 4. In this example, it is assumed that the light source is constantly turned on while measuring the entire spot area of one wafer. Also, the number of step feeds of the wafer is N in the X direction and M in the Y direction (the spot area to be measured is N + 1 in the X direction and M + 1 in the Y direction). In the solar cell processing section A, in step S101, the wafer to be measured is sent between the measurement electrodes and positioned. In step S102, m = 0 is set, and in step S103, n = 0 is set. Then, in step S104, the measurement electrode comes into contact with the wafer to be measured, and the optical-electrical characteristics are measured. That is, the current-voltage characteristics of the spot area irradiated with light are measured. When this measurement is completed, in step S105, a trigger signal is transmitted, and the measurement electrode is separated from the wafer to be measured. Then, in step S106, it is checked whether or not n is N. If n is N, the process proceeds to step S107, and it is checked whether m is M. If m is M, in step S108, the wafer to be measured is removed from the measurement position and carried out of the apparatus.
[0014]
If it is determined in step S106 that n is not equal to N, the process proceeds to step S109, and it is checked whether m is an even number. If m is an even number, in step S110, the wafer to be measured is sent one step in the X direction, and the process proceeds to step S111. If it is determined in step S109 that m is not an even number, in step S112, the wafer to be measured is sent one step in the −X direction, and the process proceeds to step S111. After n = n + 1 in step S111, the process returns to step S104.
If it is determined in step S107 that m = M is not satisfied, the process proceeds to step S113, in which the wafer to be measured is moved one step in the Y direction. In step S114, m = m + 1, and the process returns to step S103.
[0015]
In the data processing section B, when the wafer to be measured is loaded in step S101 of the wafer processing section A, p = 0 is set in step S201, and q = 0 in step S202. Wait for the trigger signal to be transmitted from the unit A. In step S203, when the trigger signal transmitted in step S105 of the wafer processing unit A is received, the process proceeds to step S204, and the measurement data obtained in step S104 of the wafer processing unit A is fetched. Then, in step S205, the maximum output Pmax is obtained based on the acquired measurement data, and the FF value is calculated. Next, in step S206, it is checked whether or not q is N. If q is N, the process proceeds to step S207, where it is checked whether or not p is M. If p is M In step S208, a measurement result and a calculation result of the measured wafer whose measurement has been completed are obtained, and the determination and sorting are performed on the measured wafer. That is, defective products are excluded, and good products are classified according to their characteristics. When a defective product occurs, feedback is performed on the production line (step S209).
[0016]
If it is determined in step S206 that q is not N, the process proceeds to step S210, where q = q + 1. After waiting for transmission of a trigger signal, the process proceeds to step S203.
If it is determined in step S207 that p is not M, the process proceeds to step S211 and sets q = q + 1, and then returns to step S202.
[0017]
In the above-described first embodiment, the measurement target wafer 1 is step-moved in the XY direction. However, the measurement electrode 8 is moved by step-moving the measurement electrode driving means 12 on the XY plane. , 9 may be moved stepwise in the XY directions. Alternatively, the wafer 1 to be measured may be step-moved only in the X direction, for example, and the measurement electrodes 8 and 9 may be step-moved in the Y direction, so that both the wafer to be measured and the measurement electrodes may be step-moved.
[0018]
FIG. 6 is a perspective view of a main part showing a second embodiment of the present invention. 6, members having the same functions as those of the first embodiment shown in FIG. 1 are given the same reference numerals. In the present embodiment, the wafer 1 to be measured is vertically held by wafer holding means 6 movable in the Y and Z directions. The electrode holding means 10 for holding the light source / measuring electrode 8 and the electrode holding means 11 for holding the counter measurement electrode 9 are moved in the left and right direction by the measurement electrode driving means 12.
The device of the present embodiment also operates in the same manner as the device of the first embodiment, and can achieve the same effects as those of the device of the first embodiment. Also in the present embodiment, the measurement electrode side can be changed to be step-movable in the Y and Z directions, or one of the measurement electrode and the wafer to be measured is step-moved in the Y direction and the other is step-moved in the Z direction. It can be changed.
[0019]
FIG. 7 is a perspective view showing a third embodiment of the present invention. 7, the members having the same functions as those of the first embodiment shown in FIG. 1 are given the same reference numerals. In the present embodiment, the wafer 1 to be measured is placed on an opposed measurement electrode stage 16 fixed on a YX table 15 that moves stepwise in the Y and X directions. A plate-like or mat-like counter measurement electrode (not shown) is arranged between the wafer 1 to be measured and the counter measurement electrode stage 16, and a high impurity concentration layer or a high impurity concentration layer formed on the back surface of the wafer 1 to be measured. It is in contact with the back electrode. The light source / measuring electrode 8 is moved up and down by the electrode holding means 10 to perform measurement with the wafer 1 to be measured sandwiched between the electrode and the opposing measuring electrode.
Also in the apparatus of the present embodiment, the wafer to be measured may be fixed so that the measurement electrode side can be step-moved in the X and Y directions. In addition, both the measurement electrode and the wafer to be measured can be moved stepwise.
The counter measurement electrode can be changed as follows. That is, a plurality of pins, such as pogo pins, that can elastically contact each other are erected on the opposing measurement electrode stage 16 to form opposing measurement electrodes. In the above description, the facing measurement electrode is brought into contact with the entire surface of the wafer to be measured. However, when a back electrode is formed on the back surface of the wafer or when a metal substrate is used, the back electrode or the metal substrate is partially used. An opposing measurement electrode that comes into direct contact can be used. In the case of a thin-film solar cell, a clip electrode that elastically contacts an exposed portion of a back electrode formed on a substrate can be used as a counter measurement electrode.
[0020]
FIG. 8 is a perspective view of a main part showing a fourth embodiment of the present invention. The difference of the present embodiment from the first embodiment shown in FIG. 1 is that in the first embodiment, one light source / measuring electrode 8 and one opposed measuring electrode 9 are provided, and one light irradiation is performed. While the measurement is performed for each spot, in the present embodiment, four measurement electrodes 8 serving as a light source and the opposite measurement electrode 9 are provided in a line. Then, in the present embodiment, the measurement is collectively performed on the four light irradiation spots. According to the present embodiment, the time for measurement and evaluation can be reduced.
[0021]
FIG. 9 is a perspective view of a main part showing a fifth embodiment of the present invention. The difference of this embodiment from the fourth embodiment shown in FIG. 8 is that, in the fourth embodiment, the light source / measuring electrode 8 and the opposing measuring electrode 9 are continuous in a line in a line. In the present embodiment, on the other hand, in the present embodiment, the light source / measuring electrode 8 and the opposing measuring electrode 9 are arranged in two rows, and each measuring electrode corresponds to one light irradiation spot in the X direction and the Y direction. This is a point that is arranged at intervals. As in the case of the fourth embodiment, when the measurement electrode 8 also serves as a light source, the measurement accuracy may be reduced due to interference between adjacent light irradiation spots. It is desirable to separate the measurement electrodes as described above. In the present embodiment, it is necessary to move three steps after moving one step in the X and Y directions.
[0022]
FIG. 10A is a perspective view of a main part showing a sixth embodiment of the present invention, and FIG. 10B is a plan view of the main part. In the fourth embodiment shown in FIG. 8, the light source / measuring electrode 8 and the opposing measuring electrode 9 are arranged in a line, but in the present embodiment, the entire light receiving area of the wafer 1 to be measured is covered. They are arranged in a matrix so that they can be covered. The measurement electrode 8 and the counter measurement electrode 9 are also held by box-shaped electrode holding means 10 and 11 which can move up and down, respectively. In the fourth and fifth embodiments, the measurement is performed on a plurality of spots at the same time, but in the present embodiment, the measurement is performed on each spot. That is, the power supply 17 for the light source and the measuring device 18 are sequentially connected to the measurement electrode 8 for the light source and the counter measurement electrode 9 via the scanning circuit 19, and the lighting of the light source and the measurement of the light irradiation spot area are sequentially performed.
[0023]
Next, the operation of the present embodiment will be described. As shown in FIG. 10A, the wafer 1 to be measured is transferred between the electrode holding units 10 and 11 and positioned by the transfer unit (not shown). Next, the electrode holding means 10 and 11 are respectively raised and lowered by the driving means (not shown), and the wafer 1 to be measured is sandwiched between the measurement electrodes 8 and 9. First, for example, the light source / measuring electrode 8 at the uppermost left end of FIG. 10B and its light source are connected to the measuring instrument 18 and the light source power supply 17 via the scanning circuit 19, and face the measuring electrode 8. The opposing measurement electrode 9 at the position is connected to the measuring device 18 via the scanning circuit 19, the light source at that position is turned on, and the spot area is measured. When the measurement of the first spot area is completed, the scanning circuit 19 switches the connection of the light source power supply 17 and the measuring device 18 to the light source / measurement electrode 8 located on the right side of the uppermost left end. The measuring device 18 is connected to the opposing measurement electrode 9 located at a position opposing the position 8, and the measurement of the second spot area is performed. Similarly, the connection to the light source power supply 17 and the connection of the measuring device 18 to the measuring electrodes 8 and 9 are sequentially switched by the scanning circuit 19 in the same manner, and the measurement is repeated. When the measurement of the entire light receiving region of the wafer 1 to be measured is completed, that is, when the scanning of the scanning circuit 19 for all the light source / measuring electrodes 8 and the opposing measuring electrodes 9 is completed, the electrode holding means 10 and 11 are driven by driving means (not shown). ), The wafer 1 to be measured is carried out, and the wafer 1 to be measured is carried out to the outside by carrying means (not shown).
When a high impurity concentration layer or a back electrode is formed on the back surface of the wafer 1 to be measured, a single plate-shaped or mat-shaped opposed measurement electrode is used instead of using a plurality of opposed measurement electrodes arranged in a matrix. Can be used. Alternatively, a pin that can be elastically contacted, such as a pogo pin, can be used as an opposing measurement electrode. In the case of a thin-film solar cell, an electrode that elastically contacts the exposed portion of the back electrode formed on the substrate can be used as the counter measurement electrode.
[0024]
【Example】
A CIGS solar cell having a Mo back electrode formed on a glass substrate and having a light-receiving surface of 36 mm × 27 mm, using the apparatus shown in FIG. 7, sandwiching the back electrode with a clip electrode, has a circuit short-circuit current Isc, and circuit open voltages Voc and Ic -V characteristics were measured. The spot light diameter is 3 mm, the step movement width in the XY directions is 3 mm, and the number of measurement spots is 108.
The measurement results are shown as relative values in FIGS. 11, 12, 13, and 14 are diagrams showing a circuit short-circuit current Isc, a circuit open-circuit voltage Voc, a maximum output power Pmax, and a fill factor FF, respectively. It is a collection of nine line graphs showing the results of 12 spot measurements in the X direction. In each figure, different line graphs show the measurement results at different positions in the Y direction. The middle part of each figure is a graph showing an in-plane distribution created based on the data shown in the uppermost part.
The degree of variation of the data in the plane can be determined from the upper diagram in each diagram. For example, it can be seen that the distribution of Pmax has a variation width of 3% in the plane. The acceptance / rejection criterion is set based on the width of the distribution and the required quality level of the product, and the acceptance / rejection is determined. In the case of rejection, improvement plan information can be created from the analysis of the evaluation parameters and other evaluation parameters that are the main causes of rejection, and this can be fed back to the manufacturing process. In addition, the position and spread of the abnormality on the light receiving surface of the battery can be grasped from the middle part of each figure.
[0025]
【The invention's effect】
As described above, the present invention is to measure the photo-electrical characteristics of the solar cell by irradiating the light receiving surface of the solar cell with the spot light and bringing the measurement electrode into contact with the outer periphery of the spot light irradiating section. Can be measured, and the internal uniformity of performance can be evaluated. Therefore, according to the present invention, it is possible to diagnose local deterioration and abnormality inside the solar cell, and feed back the information to the manufacturing process to remove defective elements and obtain a high-quality product that is unlikely to change with time. Supply becomes possible.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view of a first embodiment of the present invention.
FIG. 2 is a perspective view of a main part of the first embodiment of the present invention.
FIG. 3 is a bottom view and a cross-sectional view showing an example of a light source / measuring electrode used in the evaluation apparatus of the present invention.
FIG. 4 is a block diagram of a control unit according to the first embodiment of the present invention.
FIG. 5 is a flowchart showing an operation according to the first embodiment of the present invention.
FIG. 6 is a perspective view of a main part of a second embodiment of the present invention.
FIG. 7 is a perspective view of a third embodiment of the present invention.
FIG. 8 is a perspective view of a main part of a fourth embodiment of the present invention.
FIG. 9 is a perspective view of a main part according to a fifth embodiment of the present invention.
FIG. 10 is a perspective view of a main part and a plan view of a main part according to a sixth embodiment of the present invention.
FIG. 11 is a line graph and a relative plane distribution diagram showing in-plane spot measurement results of a CIGS solar cell circuit short-circuit current Isc in one embodiment of the present invention.
FIG. 12 is a line graph and a relative surface distribution diagram showing in-plane spot measurement results of the CIGS solar cell circuit open-circuit voltage Voc in one embodiment of the present invention.
FIG. 13 is a line graph and a relative surface distribution diagram showing in-plane spot measurement results of the CIGS solar cell maximum output power Pmax in one embodiment of the present invention.
FIG. 14 is a line graph and a relative surface distribution diagram showing in-plane spot measurement results of the CIGS solar cell fill factor FF in one embodiment of the present invention.
[Explanation of symbols]
1. Wafer to be measured
2 Dark box
3 base
4 Wafer carrier
5 Guide rail
6 Wafer holding means
7 Guide for holding means
8 Measurement electrode combined with light source
81 Fixed part
82 insulating cylinder
83 Voltage measurement electrode
84 Current measuring electrode
85 Insulation ring
86 light source
87 spring
9 Counter electrode
10, 11 electrode holding means
12 Measurement electrode driving means
13 Control unit
14 Air conditioning unit
15 XY table
16 Opposite measurement electrode stage

Claims

A first contact member having a spot light irradiation unit, a first electrode unit surrounding the spot light irradiation unit, and having a front end portion capable of contacting a light irradiation surface of the solar cell; and the first electrode unit. A second electrode portion having an equivalent outer shape and provided so as to face the first electrode portion and having a tip portion capable of contacting the back surface of the contact portion of the first electrode portion of the solar cell. A second contact member, a solar cell holding member for holding the solar cell, and a circuit short circuit current or a circuit open voltage or current of the solar cell under a spotlight connected to the first and second electrode portions. A solar cell performance evaluation device, comprising: a measurement unit for measuring voltage characteristics.

A first contact member having a spot light irradiating means, a first electrode section surrounding the spot light irradiating means and having a tip portion capable of contacting a light irradiating surface of the solar cell, and a back side of the solar cell or the sun. A second electrode portion capable of contacting the back electrode of the battery, a solar cell holding member for holding the solar cell, and a circuit of the solar cell connected to the first and second electrode portions and under a spotlight A performance evaluation device for a solar cell, comprising: a measurement unit configured to measure a short-circuit current, an open circuit voltage, or a current-voltage characteristic.

The solar cell performance evaluation device according to claim 1, wherein the second electrode unit includes a current measurement electrode and a voltage measurement electrode.

The solar cell performance evaluation device according to claim 1, wherein the second electrode portion has a cylindrical shape, and a contact portion thereof has a ring shape.

The said 2nd electrode part is a thing which contacts the back surface side or back surface side electrode of a solar cell entirely, at multiple points, or partly, The said 2nd electrode part. Solar cell performance evaluation device.

The solar cell performance evaluation device according to any one of claims 1 to 5, wherein the first electrode unit includes a current measurement electrode and a voltage measurement electrode.

The said 1st electrode part is making cylindrical shape, The said spot light irradiation means is arrange | positioned in a center hollow part, and the contact part with the solar cell has comprised the ring shape. 7. The performance evaluation device for a solar cell according to any one of claims 6 to 6.

The solar cell performance evaluation device according to any one of claims 1 to 7, wherein the spot light irradiating unit is an optical fiber having one end facing a light source, a single-color LED, or a white LED.

At least one of the first electrode and the solar cell holding member is movable stepwise, and the first electrode is relatively stepwise movable in the XY direction on the solar cell. The solar cell performance evaluation device according to any one of claims 1 to 8, wherein the light irradiation position is moved stepwise.

The solar cell performance evaluation device according to any one of claims 1 to 8, wherein a plurality of first contact members are provided, and a measurement unit is provided for each contact member.

The solar cell according to any one of claims 1 to 8, wherein a plurality of first contact members are provided, and a scanning circuit that switches a connection between the measurement unit and the first contact member is provided. Performance evaluation equipment.

The solar cell performance evaluation device according to claim 11, wherein light irradiation by the spot light irradiation means of the first contact member is sequentially switched by a scanning circuit.

13. The solar cell performance evaluation device according to claim 11, wherein a plurality of first contact members are provided so as to cover the entire light receiving region of the solar cell.

The solar cell performance evaluation device according to claim 1, wherein the solar cell is arranged in a dark place.

The solar cell performance evaluation device according to any one of claims 1 to 14, wherein an atmosphere in which the solar cell is arranged can be adjusted.

Irradiating the light irradiation surface of the solar cell with a spot light, contacting an electrode with the outer periphery of the spot light, and measuring a short circuit current or a circuit open voltage or a current-voltage characteristic of the solar cell under the spot light. Solar cell performance evaluation method.

The method according to claim 16, wherein the measurement is performed by a four-terminal measurement method.

The method for evaluating the performance of a solar cell according to claim 16 or 17, wherein the spot light is moved stepwise in the XY directions to measure in-plane characteristics of the solar cell.

Determining a variation width of a characteristic distribution on a solar cell surface with respect to a maximum power or a fill factor or a circuit short-circuit current or a circuit open voltage calculated from a measurement result, and performing a performance evaluation or a product quality screening based on the obtained width. Item 19. The performance evaluation method for a solar cell according to Item 18.

20. The method for evaluating the performance of a solar cell according to claim 16, wherein the measurement is performed in a state where the electrode on the light incident surface side of the solar cell is not formed.