Patent ID: 8351183

Claim:
An electric double layer capacitor, comprising: positive and negative electrodes; positive and negative lead wires connected to the positive and negative electrodes, respectively; a separator positioned between the positive and negative electrodes to electrically insulate the positive and negative electrodes from each other; a housing accommodating the positive and negative electrodes and the separator; an electrolyte received in the housing; and positive and negative terminals connected to the positive and negative lead wires, respectively, wherein the separator is a non-woven fabric formed by means of a melt-blown process so that pores formed in the non-woven fabric have cross sections of polygonal shapes, and wherein the cross sections of the pores in the separator have a maximum width of 2 μm or less, and wherein a length-to-width ratio of unit fibers of the separator is at least 3, and an electrolyte permeability index of the separator is 1.3 to 3 times as great as an electrolyte permeability index of the electrodes, and wherein when a pressure of 5 kg/cm 2 is applied at a temperature of 20° C. to 200° C., a ratio of an increased length of the separator in comparison to an initial length of the separator is less than 10%, and a ratio of a decreased length of the separator entirely dried in comparison to a length of the separator in which the electrolyte is permeated is less than 1%.