NOVELTY - The safety device (S) integrated with battery cover (10) comprises electric current breaker and gas emission mechanism on an electrically-conductive board (40). The battery cover is made of nickel series metal or iron-type metal having elasticity modulus higher than the elasticity modulus of safety valve (20) of safety device. The convex portions (14) formed in the power supply element sides of flanges (11) of battery cover are stuffed into the flange surfaces of safety valve.    USE - Battery cover-safety device integrated assembly for lithium ion secondary battery (claimed) used in electronic device, motor vehicle and construction machine.    ADVANTAGE - The convex portions formed in power supply element sides of flanges of battery cover are stuffed into flange surfaces of safety valve of safety device. Thus risk abnormality of battery can be eliminated appropriately, electric current interruption state can be reliably maintained after abnormality elimination and safety can be ensured. Vibration impact, change in resistance and amount of electric current generated when using battery in motor vehicle and construction machine can be reduced. The convex portions of battery cover can be stuffed into safety valve easily, the battery cover and safety device can be integrated strongly and positional shift of cover and safety device can be reduced, since battery cover is made of metal having elasticity modulus higher than that of safety valve in safety device. The safety device and battery cover are integrated with favorable manufacturing efficiency at single process and thus manufacturing process is reduced and productivity is improved.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for secondary battery.    DESCRIPTION OF DRAWING(S) - The drawing shows a cross-sectional view of the battery cover-safety device integrated assembly. (Drawing includes non-English language text)    Battery cover (10)    Flanges of battery cover (11)    Convex portions (14)    Safety valve (20)    Electrically-conductive board (40)    Safety device (S)