The present invention relates to a secondary battery having improved output and safety. In one embodiment, disclosed is a secondary battery comprising: an electrode assembly comprising a first electrode, a second electrode and a separator; a case for accommodating the electrode assembly; and a cap assembly coupled to the upper part of the case, wherein the first electrode comprises a first current collector, a first active material layer in which the first active material layer is applied onto the first current collector, a first uncoated area on which a first active material is not applied, and a first electrode tab electrically connected to the first current collector, and the first electrode tab comprises a current collection tab, which is a part of the first current collector, and a lead tab attached to the first current collector.

An electrode assembly, a battery cell, a battery, and a method and device for manufacturing an electrode assembly are provided. In some embodiments, the electrode assembly includes a positive electrode plate and a negative electrode plate. The positive electrode plate and the negative electrode plate are wound or folded to form a bend region. The positive electrode plate includes a plurality of bend portions located in the bend region. Each bend portion includes a positive current collecting layer and a positive active material layer. The positive current collecting layer is coated with the positive active material layer on at least one surface in a thickness direction of the positive electrode plate. A barrier layer is disposed between the positive current collecting layer and the positive active material layer.

Method for pre-lithiating an anode, wherein the method comprises the steps of: packing an anode sheet with a lithium-comprising sheet as a jelly roll or stack in an electrolyte; transferring lithium ions to the anode sheet to obtain a pre-lithiated anode sheet by direct contact between the anode sheet and the lithium-comprising sheet or by discharging or charging the anode sheet towards the lithium-comprising sheet; and dividing the pre-lithiated anode sheet into a plurality of pre-lithiated anodes of a desired size and shape. The invention further relates to an electrochemical cell comprising an an-ode which is pre-lithiated by the method.

Method for pre-lithiating an anode, wherein the method comprises the steps of: packing an anode sheet with a lithium-comprising sheet as a jelly roll or stack in an electrolyte; transferring lithium ions to the anode sheet to obtain a pre-lithiated anode sheet by direct contact between the anode sheet and the lithium-comprising sheet or by discharging or charging the anode sheet towards the lithium-comprising sheet; and dividing the pre-lithiated anode sheet into a plurality of pre-lithiated anodes of a desired size and shape. The invention further relates to an electrochemical cell comprising an an-ode which is pre-lithiated by the method.

An energy storage device according to an aspect of the present invention includes: a negative electrode including a negative substrate made of pure aluminum or an aluminum alloy, a conductive layer directly or indirectly layered on the negative substrate and containing a conductive agent, and a negative active material layer containing a negative active material capable of occluding lithium ions at a potential of 0.05 V vs. Li/Li.sup.+ or lower; and a positive electrode opposed to the negative electrode and including a positive substrate and a positive active material layer directly or indirectly layered on the positive substrate, and the negative active material layer is layered on the negative substrate and the conductive layer so as to include a region in contact with the negative substrate and a region in contact with the conductive layer.

An energy storage device according to an aspect of the present invention includes: a negative electrode including a negative substrate made of pure aluminum or an aluminum alloy, a conductive layer directly or indirectly layered on the negative substrate and containing a conductive agent, and a negative active material layer containing a negative active material capable of occluding lithium ions at a potential of 0.05 V vs. Li/Li.sup.+ or lower; and a positive electrode opposed to the negative electrode and including a positive substrate and a positive active material layer directly or indirectly layered on the positive substrate, and the negative active material layer is layered on the negative substrate and the conductive layer so as to include a region in contact with the negative substrate and a region in contact with the conductive layer.

A cylindrical secondary battery includes: an electrode assembly including a positive electrode plate having a positive electrode multi-tab, a separator, and a negative electrode plate having a negative electrode multi-tab, the positive electrode plate, the separator, and the negative electrode plate being laminated and wound; a cylindrical can accommodating the electrode assembly; a cap plate coupled at an upper end of the cylindrical can and being electrically connected to the negative electrode multi-tab; and a positive electrode terminal protruding upwardly through the cap plate and being electrically connected to the positive electrode multi-tab.

A cylindrical secondary battery includes: an electrode assembly including a positive electrode plate having a positive electrode multi-tab, a separator, and a negative electrode plate having a negative electrode multi-tab, the positive electrode plate, the separator, and the negative electrode plate being laminated and wound; a cylindrical can accommodating the electrode assembly; a cap plate coupled at an upper end of the cylindrical can and being electrically connected to the negative electrode multi-tab; and a positive electrode terminal protruding upwardly through the cap plate and being electrically connected to the positive electrode multi-tab.

A secondary battery includes a laminate in which a positive electrode, a separator, and a negative electrode are stacked in stated order. When either or both of an affixing surface X of the positive electrode and the separator and an affixing surface Y of the negative electrode and the separator are defined as a surface Z and the length of a connecting side of a positive electrode tab connected to the positive electrode or a negative electrode tab connected to the negative electrode is defined as L, resistance A per unit area of a region P, at the surface Z, that has a rectangular shape having the connecting side and a line segment a distance 0.3L from the connecting side as one pair of opposite sides is larger than resistance B per unit area of a region Q other than the region P at the surface Z.

A secondary battery includes a laminate in which a positive electrode, a separator, and a negative electrode are stacked in stated order. When either or both of an affixing surface X of the positive electrode and the separator and an affixing surface Y of the negative electrode and the separator are defined as a surface Z and the length of a connecting side of a positive electrode tab connected to the positive electrode or a negative electrode tab connected to the negative electrode is defined as L, resistance A per unit area of a region P, at the surface Z, that has a rectangular shape having the connecting side and a line segment a distance 0.3L from the connecting side as one pair of opposite sides is larger than resistance B per unit area of a region Q other than the region P at the surface Z.