交指式背接觸電極矽晶太陽能電池之製程簡化研究與溫室氣體減量效益評估

Abstract

隨著世界經濟的快速發展，地球暖化的現象也越來越顯著，綠色能源開始受到大家的重視，而太陽照射到地球上的能量遠大於全人類對能源需求，因此太陽能發電是備受期待的能源。 交指式背接觸太陽電池（Interdigitated Back Contact, 簡稱IBC）的概念源自於1975年，其複雜結構需透過半導體黃光微影或離子佈植等高成本的製程才可完成，IBC雖可提高太陽能發電效率，但也因製造成本的大幅提高而難以量產。本研究使用現有的矽晶太陽能製造設備，在不導入微影或離子佈植等製程的條件下，以雷射與網印技術製備IBC矽晶太陽能電池，並討論射極層寬度對IBC太陽電池發電效率的影響。 實驗結果顯示，雷射開線的射極層線寬太窄或太寛，都會造成短路電流及開路電壓降低，而使效率降低。在適當的射極層線寬下串聯電阻較低，因而增加填充因子進而提高效率，最佳效率落在射極線層寬120μm時。若改採用網印製程取代雷射製程，則當射極層寬度越寬，轉換效率也增加。使用網印取代雷射製程可減少溫室氣體的排放達99.39%。

For the purpose to mitigate the global warming phenomena caused by the rapid economic development, the renewable energy is experiencing an increasing attention lately. And, solar energy is one of the most important candidates. In the past decades, the complicated structure makes the Interdigitated Back Contact silicon solar cell (IBC) hard to be mass produced eventhough it has a high conversion efficiency. Thus, this study tries to adopt an conventional and cost effective way to make IBC cell, and to investigate the impact of process conditions on IBC cell’s conversion efficiency. The experimental result reveals the insufficient and excessive fraction of emitter region defined by laser ablation leads to the decreasing of short circuit current and open circuit voltage, and thus cause the cell efficiency degradation. An adequate fraction of emitter region (4.7%, 120μm emitter width) can improve the fill factor and cell efficiency through diminishing the series resistance loss. For further power consumption and greenhouse gas emission lowering, screen printing was utilized to replace laser ablation to define the emitter region of IBC cell. It is found that the conversion efficiency is improved with the increased emitter width of the screen printed IBC cell. And 99.39% reduction of the greenhouse gas emissions has been achieved by screen printing as compared to the laser ablation method.