Connecting structure and method between grid and electrode tab of secondary battery

1. A connecting method between a grid and an electrode tab of a secondary battery, comprising:

(a) fixing the grid with a jig;

(b) cutting the grid; and

(c) stacking the grid and the electrode tab and connecting the grid and the electrode tab by means of laser welding,

wherein the connecting method further comprises pre-welding the grid by means of ultrasonic welding before the step (a), and stacking the electrode tab on the grid and aligning a location of the electrode tab after the step (b),

wherein in the step (c), the laser welding forms a laser welding portion at a region where the grid and the electrode tab are stacked,

wherein the laser welding portion is formed to have a predetermined pattern repeatedly,

wherein the predetermined pattern is a vertically uneven wave form that has laterally linear welding portions and laterally linear non-welding portions respectively formed along lateral linear lines of an upper portion and a lower portion thereof, the welding portions at the upper portion of the pattern and the welding portions at the lower portion of the pattern are connected to each other by means of laser welding at different locations along a lateral direction so as to be connected with a linear slope from the linear line of the upper portion to the linear line of the lower portion and connected with a linear slope from the linear line of the lower portion to the linear line of the upper portion, and the laser welding portion of the predetermined pattern is continuously formed in one direction from a front point to a last point thereof,

wherein one end and the other end of the predetermined pattern are separated from each other, and

wherein the predetermined pattern is formed in a lateral parallel to a virtual horizontal line.