ORGANIC/INORGANIC COMPOSITE SEPARATION FILM COATED WITH POROUS ACTIVE LAYER, AND ELECTROCHEMICAL ELEMENT WITH THE SAME

PROBLEM TO BE SOLVED: To provide an organic/inorganic composite separation film that prevents inorganic material particles in a porous active layer that a porous base material is coated with in a process of assembling an electrochemical element from being desorbed, and suppresses short-circuiting between a positive electrode and a negative electrode when the electrochemical element is overheated, and provide the electrochemical element with the same.SOLUTION: The organic/inorganic composite separation film includes (a) a polyolefin-based porous base material having many pores and (b) the porous active layer with which at least one surface of the porous base material is coated and which is formed of a mixture of many inorganic particles and a binder high polymer. The porous active layer has a peel force of 5 gf/cm or more, and the organic/inorganic composite separation film has a coefficient of thermal contraction of 50% or less in a machine direction (MD) or direction (TD) perpendicular thereto after being left one hour at 150°C.