| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve a problem that a discharge characteristic is reduced in a lithium-ion secondary battery in which a heat resistant porous film layer is formed on an electrode plate for the purpose of improving safety. <P>SOLUTION: This is the lithium ion secondary battery equipped with (a) a positive electrode composed of a complex lithium oxide, (b) a negative electrode composed of a material capable of electrochemically storing and releasing lithium, (c) a separator, (d) a nonaqueous electrolytic solution, and (e) a porous film formed on either one surface of the positive electrode and the negative electrode. This is the lithium ion secondary battery in which that porous film is composed of inorganic oxide particles and a binder, and on the surface side and the electrode side of the porous film (side contacted with positive electrode and negative electrode), particle diameters of the inorganic oxide particles constituting the porous film are respectively different, and the particle diameters of the inorganic oxide particles of the surface side of the porous film are larger than those of the inorganic oxide particles of the electrode side of the porous film. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
