| 摘要 |
PURPOSE:To improve the performance stored after being overcharged by heat- treating at 170$ or above a current collector formed with an Sn layer or a Pb-Sn layer on the surface by dip brazing. CONSTITUTION:A Pb-Ca alloy current collector is immersed in a fused Sn or Pb-Sn alloy bath, an Sn or Pb-Sn alloy layer is formed on the surface, then it is heat-treated at 170 deg. or above for the preset time. As a result, Sn is diffused in a current collector alloy matrix to prevent the collapse of the alloy layer, and an Sn-rich current collector which is effective for the overdischarge shelf performance can be obtained. The diffusion of Sn into the current collector alloy depends on the heat treatment temperature, the collapse of the current collector surface alloy layer can be suppressed as the diffusion of Sn proceeds toward the inside of the alloy layer. The performance stored after being discharged can be thereby improved. |
