Electrochemical device and manufacturing method thereof

An electrochemical device having a separator between positive and negative electrodes, wherein:

• the positive electrode has:
• a first positive-electrode current collector;
• a second positive-electrode current collector;
• and
• a third positive-electrode current collector;
• each including a positive-electrode current collector main unit of rectangular sheet shape having an active material layer formed at least on one side, as well as a positive-electrode tab formed partly on a top side of the applicable positive-electrode current collector main unit;
• wherein the second positive-electrode current collector is electrically connected to the first positive-electrode current collector via each positive-electrode tab, and the positive-electrode current collector main unit of the second positive-electrode current collector is positioned in a manner facing the back side of the positive-electrode current collector main unit of the first positive-electrode current collector;
• wherein the third positive-electrode current collector is electrically connected to the first positive-electrode current collector via a bottom side thereof opposite to the top side of each positive-electrode current collector main unit along which the positive-electrode tab is formed, said bottom side having a connection part having a width which is the same as a width of each positive-electrode current collector main unit, and the positive-electrode current collector main unit of the third positive-electrode current collector is positioned in a manner facing the front side of the positive-electrode current collector main unit of the first positive-electrode current collector;
• the negative electrode has:
• a first negative-electrode current collector;
• and
• a second negative-electrode current collector;
• each including a negative-electrode current collector main unit of rectangular sheet shape having an active material layer formed on both sides, as well as a negative-electrode tab formed partly on a top side of the applicable negative-electrode current collector main unit;
• wherein the first negative-electrode current collector is positioned between the first positive-electrode current collector and second positive-electrode current collector;
• wherein the second negative-electrode current collector is positioned between the first positive-electrode current collector and third positive-electrode current collector and electrically connected to the first negative-electrode current collector solely via each negative-electrode tab;
• and
• the separator is constituted by:
• a first separator having a first sheet area covering the front side of the negative-electrode current collector main unit of the first negative-electrode current collector, a second sheet area covering the back side, and a connection part connecting the first sheet area and second sheet area;
• and
• a second separator having a first sheet area covering the front side of the negative-electrode current collector main unit of the second negative-electrode current collector, a second sheet area covering the back side, and a connection part connecting the first sheet area and second sheet area.