BUTTON-TYPE SECONDARY BATTERY

The present invention relates to an electrode assembly, in which a first separator, a negative electrode, a second separator, and a positive electrode are wound in a state of stacked sequentially, wherein ends of the first separator and the second separator are disposed closer to a center than ends of the positive electrode and the negative electrode, the electrode assembly comprising: an electrolyte; and a can in which the electrode assembly and the electrolyte are embedded, wherein, in the electrode assembly, an expansion member is attached to at least one central end of the first separator or the second separator, and the expansion member is expanded by absorbing the electrolyte.In the present invention having the above-described configuration, when the expansion member absorbs the electrolyte so as to be expanded, and thus, an external impact or vibration is applied, the expansion member may discharge the electrolyte to attenuate impact energy and vibration energy.