To provide a battery capable of improving capacity performance by increasing the capacity of a negative electrode.
A wound electrode element 20 wherein a strip-shaped positive electrode 21 and a negative electrode 22 are wound through a separator 23 is provided. The negative electrode 22 includes metal that can be alloyed or form a compound with carbon material or lithium as a negative electrode material capable of storing/desorbing lithium. On the negative electrode 22, lithium metal is deposited halfway through charging, and the capacity of the negative electrode 22 is expressed by the sum of capacitive component due to storing/ desorbing of lithium and capacitive component due to depositing/fusing of lithium metal. Namely, if the fully charged negative electrode 22 is subjected to differential scanning calorimetry under the condition that an electrolytic solution is removed, an endothermic peak due to fusion of lithium metal can be obtained. Thereby, the capacity of the negative electrode 22 can be increased, and the capacity performance of the battery is improved.
FUJITA SHIGERU
ADACHI MOMOE
AKASHI HIROYUKI
