Electrochemical device and manufacturing method thereof
Provide an electrochemical device offering a large capacity per current collector and a low internal resistance, which is also easy to assemble. Provided is a laminated sheet body 16 S by inserting a negative-electrode continuous body 11 BW between an adjacent pair of first current collectors 12 a, 12 a with their first current collector main units 12 a 1 connected together, and also between an adjacent pair of first current collectors 12 a , 12 a with their first tabs 12 a 2 connected together, with respect to a plurality of positive electrodes 11 A arranged in the width direction apart from each other, after which the negative-electrode continuous body of the laminated sheet body is cut to the unit width dimension of an element to obtain a plurality of laminated bodies 16.
1. 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.
2. An electrochemical device according to claim 1 , wherein the negative-electrode current collector main unit is formed over an area wider than the entire surface of the positive-electrode current collector main unit.
3. An electrochemical device according to claim 1 , wherein the positive electrode consists of the first positive-electrode current collector; the second positive-electrode current collector, and the third positive-electrode current collector, the negative electrode consists of the first negative-electrode current collector and the second negative-electrode current collector, and the separator consists of the first separator and the second separator.
4. An electrochemical device according to claim 1 , wherein the connection part of the first separator covers the bottom side of the first negative-electrode current collector, and the connection part of the second separator covers the bottom side of the second negative-electrode current collector.
5. An electrochemical device according to claim 1 , wherein a surface near the tab of the first positive-electrode current collector facing the top side of the first and second negative-electrode current collectors is covered by an insulation layer, and a surface near the tab of the second negative-electrode current collector facing the top side of the first positive-electrode current collectors is covered by an insulation layer.