光伏發電(dian)是利(li)用(yong)半導體界面的(de)(de)光生伏特效(xiao)應而將光能直接轉變(bian)為電(dian)能的(de)(de)一種技術。主要由太陽電(dian)池板(組件)、控制器(qi)(qi)和逆(ni)變(bian)器(qi)(qi)三大部(bu)分組成,主要部(bu)件由電(dian)子元器(qi)(qi)件構成。太陽能電(dian)池經過串聯后(hou)進行(xing)封裝(zhuang)保護可(ke)形成大面積的(de)(de)太陽電(dian)池組件,再配合上功率控制器(qi)(qi)等(deng)部(bu)件就形成了(le)光伏發電(dian)裝(zhuang)置。
光(guang)伏(fu)發電(dian)(dian)(dian)(dian)的主要原(yuan)理(li)是半(ban)導體(ti)的光(guang)電(dian)(dian)(dian)(dian)效應。光(guang)子(zi)(zi)(zi)(zi)(zi)照(zhao)射到金屬(shu)(shu)上時,它的能量可以被金屬(shu)(shu)中(zhong)(zhong)某個(ge)電(dian)(dian)(dian)(dian)子(zi)(zi)(zi)(zi)(zi)全部(bu)吸收(shou),電(dian)(dian)(dian)(dian)子(zi)(zi)(zi)(zi)(zi)吸收(shou)的能量足夠大(da),能克服金屬(shu)(shu)內部(bu)引力做功,離開金屬(shu)(shu)表面(mian)逃逸出(chu)來,成(cheng)(cheng)為(wei)光(guang)電(dian)(dian)(dian)(dian)子(zi)(zi)(zi)(zi)(zi)。硅原(yuan)子(zi)(zi)(zi)(zi)(zi)有4個(ge)外(wai)層電(dian)(dian)(dian)(dian)子(zi)(zi)(zi)(zi)(zi),如果在純硅中(zhong)(zhong)摻(chan)(chan)入有5個(ge)外(wai)層電(dian)(dian)(dian)(dian)子(zi)(zi)(zi)(zi)(zi)的原(yuan)子(zi)(zi)(zi)(zi)(zi)如磷原(yuan)子(zi)(zi)(zi)(zi)(zi),就(jiu)成(cheng)(cheng)為(wei)N型(xing)半(ban)導體(ti);若在純硅中(zhong)(zhong)摻(chan)(chan)入有3個(ge)外(wai)層電(dian)(dian)(dian)(dian)子(zi)(zi)(zi)(zi)(zi)的原(yuan)子(zi)(zi)(zi)(zi)(zi)如硼原(yuan)子(zi)(zi)(zi)(zi)(zi),形成(cheng)(cheng)P型(xing)半(ban)導體(ti)。當P型(xing)和N型(xing)結合在一起時,接觸面(mian)就(jiu)會形成(cheng)(cheng)電(dian)(dian)(dian)(dian)勢(shi)差,成(cheng)(cheng)為(wei)太陽(yang)能電(dian)(dian)(dian)(dian)池。當太陽(yang)光(guang)照(zhao)射到P-N結后,空穴由P極(ji)區(qu)往N極(ji)區(qu)移動(dong),電(dian)(dian)(dian)(dian)子(zi)(zi)(zi)(zi)(zi)由N極(ji)區(qu)向P極(ji)區(qu)移動(dong),形成(cheng)(cheng)電(dian)(dian)(dian)(dian)流。
光(guang)(guang)電(dian)效應就(jiu)是光(guang)(guang)照使不均勻(yun)半導體或半導體與金(jin)屬結合的(de)不同部位(wei)之(zhi)間產生(sheng)電(dian)位(wei)差(cha)的(de)現象。它首先(xian)是由光(guang)(guang)子(zi)(光(guang)(guang)波)轉(zhuan)(zhuan)化(hua)(hua)為電(dian)子(zi)、光(guang)(guang)能(neng)量轉(zhuan)(zhuan)化(hua)(hua)為電(dian)能(neng)量的(de)過程(cheng);其次(ci),是形成電(dian)壓過程(cheng)。
多晶硅經過鑄錠、破錠、切(qie)片(pian)等程序(xu)后(hou),制(zhi)作(zuo)成(cheng)(cheng)待加(jia)工(gong)的(de)硅片(pian)。在硅片(pian)上摻雜和(he)擴散微量的(de)硼(peng)、磷等,就形成(cheng)(cheng)P-N結(jie)。然后(hou)采用(yong)絲(si)網印(yin)刷,將(jiang)精配(pei)好的(de)銀(yin)漿印(yin)在硅片(pian)上做成(cheng)(cheng)柵線,經過燒結(jie),同時制(zhi)成(cheng)(cheng)背電(dian)(dian)(dian)極,并在有(you)柵線的(de)面(mian)涂一層(ceng)防反射涂層(ceng),電(dian)(dian)(dian)池(chi)片(pian)就至此制(zhi)成(cheng)(cheng)。電(dian)(dian)(dian)池(chi)片(pian)排(pai)列(lie)組(zu)(zu)(zu)合成(cheng)(cheng)電(dian)(dian)(dian)池(chi)組(zu)(zu)(zu)件(jian),就組(zu)(zu)(zu)成(cheng)(cheng)了大(da)的(de)電(dian)(dian)(dian)路板。一般在組(zu)(zu)(zu)件(jian)四周包鋁(lv)框,正(zheng)面(mian)覆(fu)蓋玻(bo)璃,反面(mian)安(an)裝(zhuang)電(dian)(dian)(dian)極。有(you)了電(dian)(dian)(dian)池(chi)組(zu)(zu)(zu)件(jian)和(he)其他(ta)輔(fu)助設備,就可以(yi)組(zu)(zu)(zu)成(cheng)(cheng)發(fa)電(dian)(dian)(dian)系統(tong)。為了將(jiang)直流電(dian)(dian)(dian)轉化交流電(dian)(dian)(dian),需要安(an)裝(zhuang)電(dian)(dian)(dian)流轉換(huan)器。發(fa)電(dian)(dian)(dian)后(hou)可用(yong)蓄電(dian)(dian)(dian)池(chi)存儲,也可輸入公共電(dian)(dian)(dian)網。發(fa)電(dian)(dian)(dian)系統(tong)成(cheng)(cheng)本中,電(dian)(dian)(dian)池(chi)組(zu)(zu)(zu)件(jian)約(yue)占50%,電(dian)(dian)(dian)流轉換(huan)器、安(an)裝(zhuang)費(fei)、其他(ta)輔(fu)助部件(jian)以(yi)及其他(ta)費(fei)用(yong)占另外50%。
無論(lun)從世(shi)界(jie)還是(shi)從中國(guo)來看(kan),常規能(neng)源(yuan)(yuan)(yuan)都是(shi)很有限的。中國(guo)的一次能(neng)源(yuan)(yuan)(yuan)儲(chu)量(liang)遠遠低于(yu)世(shi)界(jie)的平均水平,大約只有世(shi)界(jie)總儲(chu)量(liang)的10%。太陽(yang)能(neng)是(shi)人(ren)類取之不盡(jin)用之不竭的可(ke)再生能(neng)源(yuan)(yuan)(yuan),具有充分的清潔(jie)性(xing)、絕對的安全性(xing)、相對的廣泛性(xing)、確實的長壽(shou)命和(he)免維護性(xing)、資源(yuan)(yuan)(yuan)的充足性(xing)及潛在的經濟性(xing)等優點,在能(neng)源(yuan)(yuan)(yuan)戰略中具有重(zhong)要地位。