| 摘要 |
PURPOSE:To prevent a rapid rise in temperature partially inside a battery even if a plurality of batteries are shorted externally in serial states, by composing separators of fine porous films which are formed of plural species of materials different in their melting points. CONSTITUTION:Separators 4 are composed by sticking fine porous films together which are formed of plural species of materials different in their melting points, that is, polypropylene and polyethylene. Even if a plurality of batteries are shorted externally in serial states, hence one part made of polyethylene low in its melting point is first dissolved and fine pores of the polyethylene are sealed to form an insulator so that a rise in temperature inside the battery can be suppressed. The other part made of polypropylene high in its melting point is not dissolved to function as an essential separator. |
