Apparatus and method for cutting electrode sheet

A method for cutting an electrode sheet, the method compti sing a step (a) of continuously transferring the electrode sheet up to a cutting point via a measuring point by using a transfer unit, the electrode sheet having a plurality of notching grooves formed at a side surface thereof, wherein, when a front notching groove disposed at a front end among the notching grooves formed in the electrode sheet is passing through the cutting point, a rear notching groove disposed in a rear end of the front notching groove among the plurality of notching grooves is configured to pass through the measuring point;

• a step (b) of detecting the rear notching groove passing through the measuring point using a detection unit to generate a notching groove detection signal, and
• a step (c) of cutting entirely across the electrode sheet at the front notching groove as the front notching groove is passing through a cutting point, by using a cutting unit when a notching groove detection signal is generated, to manufacture a unit electrode,
• wherein the detection unit at the measuring point and the cutting unit at the cutting point are separated by a distance between the front notching groove and the rear notching groove of the electrode sheet or by a multiple of the distance between the front notching groove and the rear notching groove of the electrode sheet,
• wherein the cutting entirely across the electrode sheet generates a cut in the electrode sheet that includes the front notching groove,
• wherein the detection unit comprises a line sensor installed in a direction perpendicular to a transfer direction of the electrode sheet to detect the rear notching groove of the electrode sheet passing through the measuring point and thereby to generate the notching groove detection signal,
• wherein each notching groove of the plurality of notching grooves comprises first and second notching grooves respectively formed in both side surfaces of the electrode sheet to face each other,
• wherein the line sensor comprises first and second line sensors to respectivel detect the first and second notching grooves, each of the first and second line sensors positioned so that a first portion thereof overlaps the electrode sheet and a second portion thereof does not overlap the electrode sheet in a plan view,
• wherein each of the first and second line sensors comprises a plurality of light receiving elements arranged linearly along a length of the line sensor in single file,
• wherein an electrode tab is provided on one surface of the electrode sheet, in which the first notching groove is formed,
• wherein the step (B) further comprises a step of detecting whether the electrode tab is defective through a variation in transmittance of light, which occurs when the electrode tab passes over the first line sensor,
• wherein the line sensor generates the notching groove detection signal when any one of the first and second notching grooves is detected through the first and second line sensors.
• wherein, when both the first and second notching grooves are detected through the first and second line sensors, the line sensor generates the notching groove detection signal as a mean value of a time at which the first notching groove is detected and a time at which the second notching roove is detected, and
• wherein, when both of the first and second notching grooves are not detected through the first and second line sensors, the line sensor generates a notching groove defect signal.