本发明公开了一种制备高温高延伸率动力电池用电解铜箔的方法及其添加剂，首先,将高纯铜线加热溶解生成硫酸铜电解液；其次，将制得的硫酸铜电解液过滤后进入高位槽,往高位槽中加入添加剂，然后进行电解生箔；最后，将制得的铜箔通过防氧化液处理。添加剂包括晶粒细化剂，晶粒细化剂为聚乙烯亚胺衍生物、醇硫基丙烷磺酸钠、聚乙二醇和乙撑硫脲的水溶液。本发明通过在电解铜箔过程中添加特制的添加剂，制得的铜箔具有非常好的室温及高温高延伸率，而这种电解铜箔可以防止铜箔在活性物质涂布后进行轧辊压延等压平工序中发生龟裂，在进行过充电特性试验中，可承受住过充电时的发热所引起的膨胀应力,铜箔不会产生龟裂。

The invention discloses a method for preparing electrolytic copper foil for high temperature and high elongation power battery and an additive thereof. First, the high–purity copper wire is heated and dissolved to produce copper sulfate electrolyte; the prepared copper sulfate electrolyte is filtered into a high–level bath, and additives are added into the high–level bath, and then the raw copper foil is electrolyzed. Additives include a grain refiner, which is an aqueous solution of a polyethylenimine derivative, sodium alkenyl propane sulfonate, Polyethylene glycol, and ethylenethiourea. By adding special additive in the process of electrolytic copper foil, the prepared copper foil has excellent room temperature and high temperature elongation, this kind of electrolytic copper foil can prevent copper foil from cracking in roll calendering process after coating with active material, and can withstand the expansion stress caused by heating during overcharging, copper foil does not crack.