Secondary battery

A secondary battery comprising:

• a battery case;
• and
• a plurality of electrode assemblies housed in the battery case, wherein:
• each of the plurality of electrode assemblies includes a stack structure in which a positive electrode sheet and a negative electrode sheet are stacked with a separator interposed therebetween;
• the positive electrode sheet includes:
• a first positive electrode tab protruding from a stacked region in which the positive electrode sheet and the negative electrode sheet are stacked with the separator interposed therebetween, and
• a second positive electrode tab protruding from the stacked region at a position different from where the first positive electrode tab protrudes:
• the negative electrode sheet includes:
• a first negative electrode tab protruding from the stacked region at a position different from where the first positive electrode tab and the second positive electrode tab protrude;
• and
• a second negative electrode tab protruding from the stacked region at a position different from where the first positive electrode tab, the second positive electrode tab, and the first negative electrode tab protrude;
• and
• the plurality of electrode assemblies are arranged in the battery case in a predetermined orderly arrangement;
• positive electrode sheets of adjacent two of the electrode assemblies are electrically connected to each other by joining one of the first and second positive electrode tabs of the adjacent two of the electrode assemblies to another one;
• and
• negative electrode sheets of the adjacent two of the electrode assemblies are electrically connected to each other by joining one of the first and the second negative electrode tabs of the adjacent two of the electrode assemblies to another one.