A sheet cutting and fusion apparatus including upper and lower cutters at uppermost and lowermost surfaces, respectively, of a plurality of overlapping sheets. The upper and lower cutters includes first and second cutting surfaces configured for contacting the lower cutter without any step when the upper cutter is moved vertically and the upper cutter without any step when the lower cutter is moved vertically, respectively; first and second fusion portions parallel to the first cutting surface and to the second cutting surface, respectively; first and second steps extending between the first cutting surface and first fusion portion and extending between the second cutting surface and second fusion portion, respectively; lower and upper surfaces configured to face one of the sheets, respectively; and first and second connection portions each having a curved corner connecting the lower surface and first fusion portion and connecting the upper surface and second fusion portion, respectively.

A sheet cutting and fusion apparatus including upper and lower cutters at uppermost and lowermost surfaces, respectively, of a plurality of overlapping sheets. The upper and lower cutters includes first and second cutting surfaces configured for contacting the lower cutter without any step when the upper cutter is moved vertically and the upper cutter without any step when the lower cutter is moved vertically, respectively; first and second fusion portions parallel to the first cutting surface and to the second cutting surface, respectively; first and second steps extending between the first cutting surface and first fusion portion and extending between the second cutting surface and second fusion portion, respectively; lower and upper surfaces configured to face one of the sheets, respectively; and first and second connection portions each having a curved corner connecting the lower surface and first fusion portion and connecting the upper surface and second fusion portion, respectively.

An electrode body of a secondary battery described herein includes: a core portion where electrode mixture layers of a plurality of electrode sheets are laminated; terminal connecting portions where respective current collector foil exposed portions are laminated, and a mixture layer non-facing portion where the electrode mixture layer faces the current collector foil exposed portion, the mixture layer non-facing portion being formed in a boundary between the terminal connecting portion and the core portion. In the secondary battery described herein, a short-circuit promoting portion having a predetermined depth (d) is formed in a separator provided between the electrode sheets in the mixture layer non-facing portion. Hereby, before a battery temperature rapidly increases to a high-temperature range due to occurrence of internal short-circuit between the electrode mixture layers, internal short-circuit is caused between the electrode mixture layer and the current collector foil exposed portion, so that charging can be stopped.

A lithium battery includes a wound core and tabs, in which the wound core is formed by stacking and winding an inner separator, a first electrode sheet, an outer separator, and a second electrode sheet, and the first electrode sheet and the second electrode sheet have opposite polarity; each of the inner separator and the outer separator has a clamping section, a first straight section and a tail laminating section; where, the first straight section is located in front of the first electrode sheet, the tail laminating section is a separator end, and the clamping section, the first straight section and the tail laminating section of the inner separator are respectively laminated with the clamping section, the first straight section and the tail laminating section of the outer separator; and the first straight section of the inner separator has a surface friction coefficient of 0.1-0.4.

This electrode plate for a secondary battery comprises a thin plate-shaped core formed from a metal foil and an active material layer formed on at least one surface of the core. A melted section of the metal foil forming the core is scattered at an end section of the electrode plate for a secondary battery so as to spread from the plate thickness range of the core to the end face of the active material layer, adheres thereto, and is solidified.

This electrode plate for a secondary battery comprises a thin plate-shaped core formed from a metal foil and an active material layer formed on at least one surface of the core. A melted section of the metal foil forming the core is scattered at an end section of the electrode plate for a secondary battery so as to spread from the plate thickness range of the core to the end face of the active material layer, adheres thereto, and is solidified.

A polyolefin microporous membrane is disclosed. The membrane includes a polyolefin resin having an MFR value of not greater than 2.0 g/10 min, and a crystal nucleating agent. The polyolefin microporous membrane has an air permeation resistance scaled to a thickness of 20 μm of from 100 to 500 sec/100 cc, a porosity of from 20% to 60%, and a mean flow pore size of not greater than 100 nm.

One aspect of the present invention provides a method of manufacturing a separator including: (a) obtaining a laminate by laminating a first porous support and a second porous support; (b) forming a functional layer by applying a composition including a binder and a solvent on both sides of the laminate and drying the composition; and (c) dividing the laminate into two separators along an interface formed by the lamination, and a separator manufactured using the method.

One aspect of the present invention provides a stretching apparatus for manufacturing a separator including a first stretching machine and a second stretching machine arranged in parallel with each other, in which the first stretching machine includes a plurality of first unit sections having different stretching ratios, and the second stretching machine includes a plurality of second unit sections having different stretching ratios, the overall stretching ratio by each of the first stretching machine and the second stretching machine is the same each other, and at least one stretching ratio of the first unit section and at least one stretching ratio of the second unit section are different from each other and a method of manufacturing a separator using the same.

One aspect of the present invention provides a stretching apparatus for manufacturing a separator including a first stretching machine and a second stretching machine arranged in parallel with each other, in which the first stretching machine includes a plurality of first unit sections having different stretching ratios, and the second stretching machine includes a plurality of second unit sections having different stretching ratios, the overall stretching ratio by each of the first stretching machine and the second stretching machine is the same each other, and at least one stretching ratio of the first unit section and at least one stretching ratio of the second unit section are different from each other and a method of manufacturing a separator using the same.