Lithium ion secondary battery and a method for manufacturing same

Abstract

A lithium ion secondary battery includes a positive electrode, a negative electrode and a thin film solid electrolyte including lithium ion conductive inorganic substance. The thin film solid electrolyte has thickness of 20 μm or below and is formed directly on an electrode material or materials for the positive electrode and/or the negative electrode. The thin film solid electrolyte has lithium ion conductivity of 10 −5 Scm −1 or over and contains lithium ion conductive inorganic substance powder in an amount of 40 weight % or over in a polymer medium. The average particle diameter of the inorganic substance powder is 0.5 μm or below. According to a method for manufacturing the lithium ion secondary battery, the thin film solid electrolyte is formed by coating the lithium ion conductive inorganic substance directly on the electrode material or materials for the positive electrode and/or the negative electrode.

1 - 20 . (canceled) 
   
   
       21 . A method for manufacturing a lithium ion secondary battery having a thin film solid electrolyte comprising a lithium ion conductive inorganic substance comprising a step of preparing slurry comprising the lithium ion conductive inorganic substance, a step of forming the thin film solid electrolyte of 20 μm or below by the slurry directly on an undried electrode material or materials for a positive and/or negative electrode, wherein forming of the thin film solid electrolyte on the electrode material or materials is conducted before drying of the electrode material. 
   
   
       22 . A method for manufacturing a lithium ion secondary battery as defined in  claim 21  wherein the lithium ion conductive inorganic substance is selected from a group consisting of a lithium ion conductive crystal and a lithium ion conductive glass-ceramic. 
   
   
       23 . A method for manufacturing a lithium ion secondary battery as defined in  claim 21  wherein the lithium ion conductive inorganic substance is selected from a group consisting of a lithium ion conductive crystal of Li 1+x+y Al x Ti 2-x Si y P 3-y O 12  and a lithium ion conductive glass-ceramic comprising Li 1+x+y Al x Ti 2-x Si y P 3-y O 12  as a predominant crystal phase. 
   
   
       24 . A method for manufacturing a lithium ion secondary battery as defined in  claim 22  wherein the thin film solid electrolyte comprises the lithium ion conductive crystal or the lithium ion conductive glass-ceramic in an amount of 40 weight % or more. 
   
   
       25 . A method for manufacturing a lithium ion secondary battery as defined in  claim 23  wherein the thin film solid electrolyte comprises the lithium ion conductive crystal or the lithium ion conductive glass-ceramic in an amount of 40 weight % or more.