Patent ID: 7382224

Claim:
An over-current protection device, comprising: two metal foils; and a positive temperature coefficient (PTC) material layer sandwiched between the two metal foils, exhibiting a resistivity below 0.1 Ω-cm, and comprising: a plurality of crystalline polymers, wherein at least one of the crystalline polymer exhibits a melting point below 115° C.; and a non-oxide electrically conductive ceramic powder consisting essentially of the particle size from 0.1 μm to 10 μm and having a resistivity below 500 μΩ-cm, and dispersed in the crystalline polymers; wherein the initial resistance of the over-current protection device is below 20 mΩ, the area of the PTC material layer is below 30 mm 2 , and the over-current protection device exhibits a surface temperature below 100° C. under the trip state of over-current protection.