Device for winding electrode assembly and method for controlling the same

The invention provides a device for winding an electrode assembly and a method for controlling the same. The device for winding an electrode assembly comprises a feeding reel for supplying one substrate from a negative plate, a positive plate and a separator plate; a winding center part which rotates to wind the substrate around the outer circumference of the winding center part, wherein the winding center part includes a long radius and a short radius; and a tension controller which is disposed on the substrate and moves from the feeding reel to the path of the winding center part. The tension controller conducts a linear reciprocating motion to compensate the tension difference generated by the shape of the winding center part, so that the substrate can be winded around the winding center part with a constant tension.