微透鏡陣列製作全天太陽能電池

Solar Cells with Micro-lens Array for All Day Photovoltaic Conversion

張心豪

指導教授 ： 葉哲良

國立清華大學/工學院/微機電工程研究所/碩士(2006年)

摘要

如何有效提升太陽能電池光電轉換效能，一直是此領域最重要的課題之一。本論文提出在太陽能電池表面製作透光高分子微透鏡陣列（Micro-lens Array, MLA），利用特定光學性質之高分子薄膜以增加光學吸收效能，以及利用MLA降低斜角入射光反射率和增加電池表面二次反射的方式，使太陽能電池在各種不同入射光角度都能有不錯的轉換效能。
利用體型微加工（Bulk Micro-machining）製作MLA，以電鑄方式得到金屬母模，在此金屬母模上旋塗高分子薄膜來大量製作高透光性MLA，最後再將此膜黏貼於太陽能電池表面。
製作出來的MLA太陽能電池各角度之光電轉換效果比既有的太陽能電池較佳，且隨著角度增加，相對增加量也跟著提升。在僅考慮直接入射光的影響下，加裝MLA薄膜在晴空狀況下可使太陽能電池由7.78kW-hr提升至7.92kW-hr，整體效能增加1.8%；有雲狀態下可由2.83kW-hr提升至2.90kW-hr，整體效能增加2.3%。。顯示在光強度不強的天氣狀況下反而更能凸顯MLA之特性。若再加上未列入考慮但卻實際情況不容忽略之大量散射光，提升之發電量是相當驚人的。

關鍵字

微透鏡陣列 ； 太陽電池 ； 入射角度 ； 高分子

並列摘要

The efficiency enhancement of photovoltaic (PV) is one of the most important issues in solar cells. This research proposed an optical design, polymer micro-lens array (MLA) with high transmission, to enhance the optical absorption of PV. MLA decreases the reflection of light at oblique angles and increases the second reflection at the interface between MLA and PV. MLA will enhance the efficiency of PV at any oblique angle.
The surface profile of MLA was designed and metal mold was fabricated using bulk micro-machining followed by electroplating. A high transmission polymer was spun on the metal mold to replicate a MLA thin film. Finally, thin film MLA was attached on PV surface.
The efficiency of PV with MLA film at any incident angle was measured to be better than that without MLA film. The enhancement is more significant at lager oblique angle. Neglect the diffuse irradiation, annual energy of sunny day was estimated to increase from 7.78kW-hr to 7.92kW-hr, i.e. a 1.8% increase. The annual energy of cloudy day was estimated to have a 2.3% increase, from 2.83kW-hr to 2.90kW-hr. It shows that the higher potential of MLA reeals on a cloudy ady. Considering the diffuse irradiation on actual case, out door situation, an increase rate will be higher than the above numbers can be expected.

並列關鍵字

micro-lens array ； photovoltaic ； angle of incident ； polymer

參考文獻

[1] “Report of German Advisory Council on Global Change (WBGU)”, 2003.

[3] Wissenschaftspark Gelsenkirchen, http://www.wipage.de/

[6] A. A. M. Sayigh, “Solar Energy Engineering,” Chapter 3.

[11] R. D. McConnell, J. Thompson, “A Hybrid Solar Concentrator for the Electrolytic Production of Hydrogen,” NREL Report, 2005.

[12] A. Goetzberger, C. Hebling, H. W. Schock. “Photovoltaic Materials, History, Status and Outlook,” Materials Science and Engineering, Vol. 40, pp. 1–46, 2003.