Ⅲ-V族化合物聚光型太陽能電池之 特性衰退研究分析

Study on the Electrical Characteristics Degradation of III-V Compound Concentration Solar Cells

葉宇能(Yu-Neng Ye)

指導教授 ： 溫武義

中原大學/工學院/電子工程研究所/碩士(2009年)

https://doi.org/10.6840/cycu200901102

摘要

高聚光型高效率太陽能發電(High Concentration Photovoltaic, HCPV)系統的工作原理係主要以III-V族化合物半導體材料製成的高效率多接面太陽能電池，配合聚光系統將太陽光匯聚於太陽能電池上。
就理論而言，太陽能電池使用壽命可長達三十至四十年。但在實際應用上，因處於戶外環境，長期曝露於大氣之中，受各種氣候因子的影響導致太陽能電池除了高倍率聚光熱效應所造成的損害之外，外在環境也是造成太陽能電池老化衰退的重要因素之一。
本研究主要利用模擬環境因素的方式來加速太陽能電池老化衰退，目的在探討其特性衰退現象、機制及原因，藉以了解太陽能電池長期工作之可靠度。我們依據IEC-62108 (edtion1.0)之測試條件，針對太陽能電池接收器(solar receiver)及三接面(triple junction)太陽能電池進行溫度衝擊(thermal cycle test)及電流衝擊(current attack) 進行測試，測試溫度為-40度至80度，外加電流為1.7A，藉由電流-電壓特性、暗電流以及外部量子效率等量測，分析其衰退機制，再由電流-電壓特性量測結果，計算串聯電阻(series resistance)，並探討串聯電阻對於太陽能電池之影響。
由實驗結果得知，經由溫度衝擊測試後，太陽能電池各項重要參數，如短路電流、開路電壓、填充因子、轉換效率等皆產生衰退現象，而暗電流及串聯電阻則有增加之趨勢；推測原因為太陽能電池結構層氧化，以及各層結構材料間之熱應力不平均所造成。
特別是暗電流與串聯電阻增加乃導致短路電流下降為太陽能電池特性衰退之主要因素。

關鍵字

聚光型 ； 太陽能電池 ； 衰退

並列摘要

The High Concentration PhotoVoltaic (HCPV) system is mainly based on high-efficiency III-V compound multi-junction solar cell, which concentrates the sunlight illuminated on top of the solar cell and produces an efficient and economical energy conversion process.
Theoretically, the solar cell can be expected to be used for 30 - 40 years. However, in actual operation, the HCPV system is built in the open air, and receives a long-term exposure in the atmosphere environment. Each kind of climatic factors will influence the extension of use for the HCPV system. Beside the climatic factors, the thermal effects under high light concentration condition also play an important role in the ageing of solar cell.
The purpose of this study is to examine the degradation mechanism of solar cell during its aging time by simulating the climatic effects, which accelerate the ageing of solar cell. The thermal cycle and current attack tests were conducted on solar receivers and triple-junction solar cells based on the IEC 62108(edtion1.0). The thermal cycle treatment was performed from -40℃ to 80℃ with a current attack of 1.7 A. The degradation mechanism was discussed by analyzing the results obtained from the current-voltage (I-V) measurement, dark-current measurement and external quantum efficiency measurement. In addition, the effect of series resistance evaluated from I-V measurement was also analyzed.
Conclusively, the parameters of Isc, Voc, Pmax, fill factor and efficiency, etc, all deteriorate, and also the dark-current and series resistance increase with increasing thermal cycle times. The degradation of solar cell under thermal cycle test is considered to be mainly ascribed to the reduction of Isc, resulting from the increase of dark current and series resistance, which might be due to the oxidation of solar cell and non-uniform thermal stress occurred between different layer materials of the solar cell structure.

並列關鍵字

concentration ； solar cell ； degradation

參考文獻

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