| 摘要 |
PURPOSE: A lithium secondary battery equipped with a safety relief valve in a battery case and its preparation method are provided, to allow the gas generated inside a battery to be discharged rapidly at a certain critical pressure when the internal pressure of a battery is increased for preventing the explosion of a battery and improving the safety of a battery. CONSTITUTION: The method comprises the steps of accommodating an electrode assembly comprising a positive electrode plate(60), a negative electrode plate(70) and a separator(50) which layered in a battery case(20), and projecting the positive electrode terminal(30) and the negative electrode terminal(40) connected with the positive electrode plate and the negative electrode plate, respectively, to the outside of the case; heat welding the upper part and the one side part of the case, injecting an electrolyte solution into the case, and welding the other side part to prepare a lithium secondary battery; charging the lithium secondary battery and removing the gas generated; and forming a safety relief valve(10) in the welded part of the case. Preferably the safety relief valve is formed by notching, cutting or punching.
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