SECONDARY BATTERY, LAYER-BUILT SECONDARY BATTERY AND BATTERY PACK

摘要

A secondary battery (4) comprises current collecting electrodes (21, 23), a region touching the positive electrode (28) or the negative electrode (26) out of the current collecting electrodes (21, 23), a terminal portion formed in the current collecting electrodes (21, 23) and not touching the positive electrode or the negative electrode, and a joint for connection with a conductive member. Cross-sectional area of a terminal portion constituting a first current passage between the joint and a first portion closest to the joint in the contact region is set smaller than the cross-sectional area of a terminal portion constituting a second current passage between the joint and a second portion located in a region extending along the terminal portion on the fringe of the contact region and having a distance to the joint longer than the length of the first current passage.