PTC circuit protection device and manufacturing process for same
First Claim
1. An electrical device comprising:
- a PTC element including a polymer with electrically conductive particles dispersed therein, said PTC element having first and second surfaces;
a pair of conductive layers respectively contacting said first and second surfaces of said PTC element;
a pair of electrodes, each said electrode being comprised of a metal foam material having an inner surface extending through one of said conductive layers so that said inner surface is in direct physical contact with said PTC element, and an outer surface; and
,a portion of said outer surface of each said electrode projecting outwardly from each conductive layer, respectively, so as to be connectable to a source of electrical power, and when so connected, causing current to flow through said PTC element.
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Accused Products
Abstract
Electrical devices having a PTC element of a polymer having conductive particles dispersed therein. The PTC element is coated with a conductive layer and has electrodes with a plurality of voids affixed to opposing surfaces. The devices are made by dispersing conductive particles into a polymer to form a polymer PTC composition. The polymer PTC composition is melt-shaped to form a laminar shaped PTC element. First and second opposing surfaces of the PTC element are coated with a conductive layer. The electrodes, characterized by a plurality of voids and made of foam, are brought into contact with the coated surfaces of the PTC element, and heated while applying pressure to form a laminate. The laminate is then further shaped into a plurality of PTC electrical circuit protection devices.
101 Citations
24 Claims
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1. An electrical device comprising:
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a PTC element including a polymer with electrically conductive particles dispersed therein, said PTC element having first and second surfaces; a pair of conductive layers respectively contacting said first and second surfaces of said PTC element; a pair of electrodes, each said electrode being comprised of a metal foam material having an inner surface extending through one of said conductive layers so that said inner surface is in direct physical contact with said PTC element, and an outer surface; and
,a portion of said outer surface of each said electrode projecting outwardly from each conductive layer, respectively, so as to be connectable to a source of electrical power, and when so connected, causing current to flow through said PTC element. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 24)
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22. An electrical device comprising:
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a PTC element including a polymer with electrically conductive particles dispersed therein, said PTC element having first and second surfaces and a resistivity at 25°
C. of less than 5 ohm cm;a pair of conductive thick film ink layers respectively contacting said first and second surfaces of said PTC element; a pair of electrodes, each said electrode being comprised of a metal foam material having an inner surface in direct physical contact with said PTC element and an outer surface; a portion of said outer surface of each said electrode projecting outwardly from each conductive layer, respectively, so as to be connectable to a source of electrical power, and when so connected, causing current to flow through said PTC element; and
,said electrical device having an initial resistance at 25°
C. of less than 1.0 ohm.
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23. An electrical device comprising:
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a PTC element including a polymer with electrically conductive particles dispersed therein, said PTC element having first and second surfaces and a resistivity at 25°
C. of less than 5 ohm cm;a pair of conductive layers respectively contacting said first and second surfaces of said PTC element; a pair of electrodes respectively confronting said conductive layers, each said electrode being comprised of a metal foam having an inner surface extending into said PTC element through the adjacent conductive layer and an outer surface, said inner and outer surfaces being separated by a mid-zone, at least a portion of each mid-zone being filled by said conductive layers, respectively; and
,a portion of said outer surface of each electrode projecting outwardly from each conductive layer, respectively, so as to be exposed from said conductive layer and connectable to a source of electrical power, and when so connected, causing current to flow through said PTC element; and
,said electrical device having an initial resistance at 25°
C. of less than 1.0 ohm.
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Specification