Electrical devices containing a conductive polymer element having a fractured surface

Claim 1

A circuit protection device which has a resistance at 23° C. of less than 1 ohm and which comprises (1) a laminar conductive polymer element which (a) is composed of a composition which exhibits PTC behavior and which comprises (i) a crystalline polymeric component and (ii), dispersed in the polymeric component, electrically conductive particles in an amount such that the composition has a resistivity at 23° C. of less than 10 ohm-cm, and (b) has a first principal face, a second principal face parallel to the first face, and at least one transverse face which extends from the first principal face to the second principal face and consists essentially of a fractured surface, and (c) is less than 0.1 inch thick; (2) a first metal foil electrode which has (i) an inner face which contacts the first principal face of the conductive polymer element, and (ii) an outer face; (3) a second metal foil electrode which has (i) an inner face which contacts the second principal face of the conductive polymer element, and (ii) an outer face; (4) an additional metal foil conductive member which (a) has (i) an inner face which contacts the second principal face of the conductive polymer element and (ii) an outer face, and (b) is spaced apart from the second electrode; the conductive polymer element, the first electrode and the additional conductive member defining an aperture which runs between the first electrode and the additional conductive member, through the conductive polymer element; and (5) a transverse conductive member which (a) is composed of metal, (b) lies within the aperture, and (c) is physically and electrically connected to the first electrode and the additional conductive member.