NOVELTY - The material has a negative electrode (22) including tin, iron, cobalt, carbon and titanium, bismuth, tantalum, nickel, copper, zinc, gallium, indium, tungsten and molybdenum as a constituent element. The constituent element includes silver, phosphorus, antimony, aluminum, vanadium, chromium and niobium. A peak is obtained by an X-ray diffraction. A battery cover (14), a safety valve mechanism (15) and a thermal-sensitive resistive element (16) are crimped with an opening edge part of a battery tin (11) through a gasket (17).    USE - Negative electrode active material for a secondary battery i.e. lithium ion secondary battery, utilized for an electric tool e.g. electrically-driven drill and electric saw, an electric vehicle i.e. hybrid vehicle, and an electric power storage system (all claimed) i.e. home-use battery system. Can also be used for a portable electronic device such as video camera, digital still camera, mobile telephone, notebook, personal computer, cordless telephone apparatus, headphone stereo cassette tape recorder, portable radio, portable TV and portable information terminal i.e. personal digital assistant (PDA), an electric appliance i.e. electric shaver, a storage apparatus such as backup power supply and memory card, a medical electronic device such as pacemaker and hearing aid, and a home appliance, and a cylindrical-shaped secondary battery, coin-shaped secondary battery and a laminate-film type secondary battery.    ADVANTAGE - The battery cover, the safety valve mechanism and the thermal-sensitive resistive element are crimped with the opening edge part of the battery tin through the gasket, so that outstanding effect and charge-and-discharge state of the battery can be acquired, thus improving service life of the battery, and hence reducing battery swelling.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for the following:    (1) an electric tool    (2) an electric vehicle    (3) an electric power storage system.    DESCRIPTION OF DRAWING(S) - The drawing shows a sectional view of negative electrode active material.'(Drawing includes non-English language text)'    Battery tin (11)    Battery cover (14)    Safety valve mechanism (15)    Thermal-sensitive resistive element (16)    Gasket (17)    Negative electrode (22)