Mainly depends on the cost control, the battery shrapnel materials such as iron and manganese steel, followed by phosphor copper and stainless steel, and the superior material layer is beryllium copper. The advantages are that the battery electrode has excellent conductivity and does not rust, followed by sublimation of appearance, first choice of materials, electroplating process, convenient welding and no chip falling. The author suggests that choosing the same layer of materials, phosphorus and copper, can not only save cost, but also control quality.