SECONDARY BATTERY OF EXCELLENT PRODUCTIVITY AND SAFETY

摘要

PURPOSE: A secondary battery is provided to remarkably improve safety and electrolyte-injection performance by preventing foreign substances, which are generated during assembling process, flowing into a jelly-roll. CONSTITUTION: A secondary battery comprises a structure which a jelly-roll with a positive electrode/separator/negative electrode structure is mounted to a cylindrical battery case. A planar insulating unit(180c) mounted to the top of the jelly-roll comprises: an opening(181c) punched on the insulating unit for discharging gas; and micropores(182c) which allows liquid electrolyte to pass through and does not allow foreign substance with the size of 100 micron or more to pass through. The micropores are formed on whole sides of the insulating unit and spaced apart at constant intervals.