相對于鎳鎘電池,碲化鎘電池在其使用壽命內(nèi)(不考慮回收),對鎘的使用效率要比鎳鎘電池高至少2500倍。(若考慮回收,則每千瓦時的耗鎘量將大大減少)
如果一只2號電池能被充放電1000次,在它的使用壽命中,每克鎘將產(chǎn)生0.31千瓦時的電量,比碲化鎘薄膜太陽能電池少了2500倍(碲化鎘薄膜太陽能電池為每克鎘770千瓦時)。因此,碲化鎘薄膜太陽能電池中鎘的使用價值將遠遠大于任何市場產(chǎn)品中鎘的使用價值。
參考文獻:
Leclanche. "The rechargeable batteries".. Accessed January 6, 2003.
Morrow, H. (1998). "The importance on recycling to life cycle analysis of nickel cadmium batteries." Proceedings of the 8th International Nickel Cadmium Battery Conference, Prague, Czech Republic, September 21-22, 1998.
Steatite Group, The. "A comprehensive range of industry-proven NiCd batteries." Accessed January 6, 2003.
鎘是鋅,鉛和銅礦的副產(chǎn)物。其主要礦石(ZnS)中僅含有0.25%的鎘。每年都有大量的鋅被提煉出來,因此大量的副產(chǎn)品鎘也被提煉出來(不管有多少鎘被用于制造薄膜太陽能電池)。這些鎘能被很好的用于生產(chǎn)薄膜太陽能電池或者其他產(chǎn)品,或直接被排入人類的生存環(huán)境。當市場不接收這些被提煉出來的鎘時,可以存放起來以備將來使用或者被視為危險廢物而遭到填埋。
參考文獻:
Morrow, H. (17 January 2003). Personal communication. The International Cadmium Association.
Plachy, J. (2001). U.S. Geological Survey Minerals Yearbook, Chapter 17: Cadmium.
United States Geological Survey (USGS). Table 6: U.S. statistics for zinc. (Excel 27 KB). Accessed January 6, 2003.
生產(chǎn)大規(guī)模碲化鎘薄膜太陽能電池所需要的鎘占全美國對鎘消耗的3%還不到。在未來若干年內(nèi),用少于1/3現(xiàn)有鎘產(chǎn)量的鎘來生產(chǎn)碲化鎘薄膜太陽能電池就能改變我們的供電結(jié)構(gòu)(用的大部分電將產(chǎn)自綠色環(huán)保的薄膜太陽能電池)。目前,市面上大部分的鎘被用于生產(chǎn)鎳鎘電池(~65%),17%的鎘用于生產(chǎn)油漆,10%的鎘用于生產(chǎn)塑料,5%的鎘用于電鍍,2%的鎘用于電焊。
用大大少于目前在其它行業(yè)所消耗的鎘量來制造薄膜太陽能電池就能改變目前全球的供電結(jié)構(gòu),這樣既不會影響鎘的總提煉量,又能有效的防止鎘最終被當作危險廢物而填埋掉,還能大大減少二氧化碳和其它物質(zhì)的排放。
參考文獻:
Anderson, B. A. (2000). Materials availability for large-scale thin film photovoltaics. Progress in Photovoltaics, 8, pp. 61-76.
Cadmium Market Update Analysis and Outlook. (1995). Roskill Information Services Ltd., London, UK.
碲化鎘的軟化點是1041℃,從1050℃開始蒸發(fā),而火焰的溫度為800℃-1000℃,不足以使碲化鎘蒸發(fā)。碲化鎘確實會在500℃以上升華,但這一現(xiàn)象只在2.5torr(0.003atm)的氣壓下發(fā)生。硫化鎘的熔點高達1750℃,要使其在800℃升華得將氣壓調(diào)到0.1torr。美國布魯克海文國家實驗室和德國的GSF學院曾做過實驗驗證了碲化鎘薄膜太陽能電池在火災或者意外破碎時不會釋放出碲化鎘。
參考文獻:
Drysdale, D. (1985). An Introduction to Fire Dynamics, pp. 329-330, Wiley, NY.
Moskowitz, P; Fthenakis, V. (1990). Toxic materials released from photovoltaic modules during fires; health risks, Solar Cells, 29, pp. 63-71.
Thumm, W.; Finke, A.; Nuemeier, B.; Beck, B.; Kettrup, A.; Steinberger, H.; Moskowitz, P. (1994). "Environmental and health aspects of CIS-module production, use, and disposal." Presented at the First World Conference on Photovoltaic Energy Conversion, Waikoloa, Hawaii, 5-9 December 1994.
Steinberger, H. (1997). HSE for CdTe and CIS thin film module operation, IEA expert workshop "Environmental aspects of PV power systems," May 23, 1997, Report No. 97072, Niewlaar E. and Alsema E. (ed.), Utrecht University, The Netherlands.
Patterson, M.; Turner, A.; Sadeghi, M.; Marshall, R. (1994). "HSE aspects of the production and use of CdTe thin film modules." Presented at the 12th European PV Solar Energy Conference, Amsterdam.
有毒化合物進入體內(nèi)只有達到一定劑量時才會影響我們的健康。碲化鎘薄膜太陽能電池若能影響人們的健康的唯一可能是其攝入了含碲化鎘的碎片,微?;蛘叻蹓m。而碲化鎘和硫化鎘層穩(wěn)定的被封存于兩塊玻璃中間(用EVA封存),除非薄膜太陽能電池被磨成細末,否則電池本身不可能產(chǎn)生微粒。另外,碲化鎘在常壓下也不會蒸發(fā),因此使用碲化鎘薄膜太陽能電池不可能產(chǎn)生碲化鎘粉塵。
參考文獻:
Bohland, J.; Dapkus, T.; Kamm, K.; Smigielski, K. (1998). "Photovoltaics as hazardous materials: the recycling solution." Proceedings of the 2nd IEEE World Photovoltaic Specialists Conference, pp. 716-719.
Fthenakis V. (2002). "Could CdTe PV modules pollute the environment?" Aug. 2002, Brookhaven National Laboratory, Upton, NY 11973.
Fthenakis, V.; Eberspacher, C.; Moskowitz, P. (1996). "Recycling strategies to enhance the commercial viability of photovoltaics." Progress in Photovoltaics, 4, pp. 447-456. Fthenakis, V.; Gonsiorawski, R. (1999). Lead-free solder technology from ASE Americas, Workshop Report BNL-67536, Oct. 19, 1999, Brookhaven National Laboratory, Upton, NY 11973.
Steinberger, H. (1997). HSE for CdTe and CIS thin film module operation, IEA expert workshop. "Environmental aspects of PV power systems." May 23, 1997, Report No. 97072, Niewlaar E. and Alsema E. (ed.), Utrecht University, The Netherlands.