Cylindrical battery with spirally wounded electrode assembly

摘要

The battery has an electrode group configured by rolling up two sheet electrodes (7, 9) of opposite polarity in spiral fashion with a separator (8) interposed therebetween. At least one of the electrodes (7, 9) comprises a porous metal substrate having a higher porosity layer and a lower porosity layer which has a considerably smaller thickness than that of the higher porosity layer, and an active material substantially fills the spaces of the higher porosity layer. The cylindrical battery has a high utilization rate and a high discharge capacity rate.