Gas discharge valve of battery and battery

A battery gas discharge valve formed at a battery, comprising:

• a thin valve body to be opened to release gas from an inside to an outside of the battery when an internal pressure of the battery has reached a predetennined value or greater,
• wherein the valve body includes a substantially annular main notch for opening the valve body and an auxiliary notch provided in a region inside the main notch,
• the main notch and the auxiliary notch are coupled to each other at least at one location,
• at a coupling portion between the main notch and the auxiliary notch, a curvature R1 of an inner corner of a bottom portion of the main notch is equal to or less than 0.05, and a curvature R2 of an outer corner of the bottom portion of the main notch is equal to or greater than 0.05, and
• t2/t1≥0.16 is satisfied assuming that a thickness of the valve body at a portion thereof located in the opposite direction of the auxiliary notch when view ed from the coupling portion is t1 and a thickness of the valve body at a portion thereof located below the bottom portion of the main notch is t2.