| abstract |
A porous thermoplastic resin film capable of functioning well as a separator of a cell is provided. The porous film is constituted with a thermoplastic resin and a filler, wherein XR defined by the following formula:is smaller than 5, where Y(mum), TGUR (sec/100 cc), and d (mum) represent the thickness, the gurley value, and the average pore diameter of said film, respectively. The porous film constructed as shown above can reduce the internal resistance of a cell when used as a separator of the cell. |