A secondary battery and a secondary battery array are disclosed. In one aspect, the secondary battery includes an electrode assembly and a battery case accommodating the electrode assembly. The battery also includes a plurality of lead terminals comprising a first pair of lead terminals having opposite polarities and outwardly extending from the electrode assembly to protrude from a first side of the battery case and a second pair of lead terminals having opposite polarities and outwardly extending from the electrode assembly to protrude from a second side of the battery case opposing the first side. The battery further includes a plurality of insulation members respectively extending along the first and second pairs of lead terminals to at least partially cover the lead terminals.