化学还原制备晶硅太阳能电池背电极用银微粉

Preparation on Silver Micro-powders for Back Electrode of Crystalline Silicon Solar Cell by Chemical Reduction Method

采用化学还原制备晶硅太阳能电池背电极用银微粉,以聚乙烯醇(PVA)作分散剂,甲醛作为还原剂,氨水调节pH,通过扫描电镜、激光粒度仪等分析银微粉的形貌和粒径,研究还原温度、分散剂用量、还原剂加入硝酸银溶液的速率等工艺条件对银粉形貌和粒径的影响。结果表明,在硝酸银溶液浓度1 mol/L,甲醛溶液浓度1.2 mol/L,pH=3,还原温度为50℃,分散剂PVA添加量为硝酸银质量的1%,还原剂溶液加入速率为100 mL/min时,制备得到平均粒径0.89μm、振实密度5.42 g/cm^(3)、比表面积1.2 m^(2)/g的高分散性银微粉。按银微粉添加量为60%、玻璃粉添加量2%、有机载体为38%配制的背电极银浆,经烘干、烧结固化后测试背电极350℃焊接拉力4.3 N,450℃焊接拉力5.8 N,150℃恒温1 h的老化附着力为(2.5~3.0)N。

Chemical reduction method is adopted to prepare silver micro-powders for back electrode of crystalline silicon solar cell,polyvinyl alcohol(PVA)is taken as dispersing agent,formaldehyde is taken as reducing agent,ammonia is used to adjust pH value,the morphology and particle size of silver powder is analyzed by scanning electron microscope and laser particle analyzer,it is studied the effect of reduction temperature,dispersing agent dosage,the addition velocity of reducing agent that added into silver nitrate solution,and the other process conditions.Results show,when the concentration of silver nitrate solution is 1 mol/L,the concentration of formaldehyde solution is 1.2 mol/L,pH=3,the reduction temperature is 50℃,the addition amount of dispersing agent PVA is 1% of silver nitrate mass,the addition velocity of reduction solution is 100 ml/min,the prepared highly dispersible silver powder has the following parameters,the average particle size is 0.89μm,the tapping density is 5.42 g/cm^(3),the specific surface area is 1.2 m^(2)/g.The back electrode silver paste prepared by the following parameters that the addition amount of silver micro-powder is 60%,the addition amount of glass powder is 2%,the organic carrier is 38%,the back electrode was tested after drying and sintering cured,its bond pull is 4.3 N when the temperature is 350℃,its bond pull is 5.8 N when the temperature is 450℃,its aging adhesion is(2.5~3.0)N when the constant temperature is 150℃for 1 h.