Solar cell and method of making same
First Claim
1. A solar cell comprising:
- a semiconductor substrate having a front surface, a rear surface, and a shallow p-n junction adjacent said front surface;
a first electrode affixed in mechanical and electrical contact with said rear surface;
an array of narrow, elongate, second electrodes affixed in mechanical and low resistance electrical contact with said front surface;
an anti-reflection coating overlying and bonded to said front surface in flanking relation to each of said second electrodes, said anti-reflection coating having a front surface facing away from said substrate; and
at least one third electrode formed from a paste or an epoxy resin composition that contains conductive metal particles, said third electrode being bonded to said front surface of said anti-reflection coating and extending across said array of second electrodes at an angle to each of said second electrodes, said third electrode being in direct electrical contact with each of said second electrodes and also being spaced from and out of contact with the front surface of said semiconductor substrate by portions of said anti-reflection coating.
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Accused Products
Abstract
An improved solar cell of the type including a semiconductor substrate having a shallow p-n junction adjacent its front surface, a rear electrode affixed in adherent mechanical and electrical contact with the rear surface of the semiconductor substrate, and a front generally grid-shaped electrode including an array of narrow, elongate, parallel fingers and at least one bus bar extending at right angles to the fingers in electrical contact therewith affixed in mechanically adherent and low resistance electrical contact with the front surface of the semiconductor substrate. The improvement includes the removal of the bus bar portion of the front grid-shaped electrode from intimate mechanical and electrical contact with the front surface of the semiconductor substrate. The improvement increases the open circuit voltage and efficiency of the solar cell, and allows the bus bar portion of the grid shaped electrode to be formed of materials different from the finger portions of that electrode thereby providing cost advantages and design flexibility without detriment to solar cell efficiency. A method of making the improved solar cell also is disclosed.
123 Citations
21 Claims
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1. A solar cell comprising:
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a semiconductor substrate having a front surface, a rear surface, and a shallow p-n junction adjacent said front surface; a first electrode affixed in mechanical and electrical contact with said rear surface; an array of narrow, elongate, second electrodes affixed in mechanical and low resistance electrical contact with said front surface; an anti-reflection coating overlying and bonded to said front surface in flanking relation to each of said second electrodes, said anti-reflection coating having a front surface facing away from said substrate; and at least one third electrode formed from a paste or an epoxy resin composition that contains conductive metal particles, said third electrode being bonded to said front surface of said anti-reflection coating and extending across said array of second electrodes at an angle to each of said second electrodes, said third electrode being in direct electrical contact with each of said second electrodes and also being spaced from and out of contact with the front surface of said semiconductor substrate by portions of said anti-reflection coating. - View Dependent Claims (2, 3, 4, 5)
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6. A method of making a solar cell, comprising:
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(a) providing a semiconductor substrate having a front surface, a rear surface, a shallow p-n junction adjacent said front surface, an anti-reflection coating overlying and bonded to said front surface, and a first electrode in mechanical and electrical contact with said rear surface; (b) forming an array of narrow, elongate, and mutually spaced second electrodes on said front surface of said semiconductor substrate such that each of said second electrodes is in mechanically adherent and low resistance electrical contact with said front surface of said semiconductor substrate and is flanked by said anti-reflection coating; and (c) affixing at least one elongate third electrode to said front surface of said anti-reflection coating and each of said second electrodes such that said at least one third electrode extends across said array of second electrodes and is displaced from said front surface of said semiconductor substrate by said anti-reflection coating, said third electrode being formed from a first paste or an epoxy resin that contains conductive metal particles. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14)
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15. A solar cell comprising:
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a silicon semiconductor substrate having a front surface, a rear surface, and a shallow p-n junction adjacent said front surface; an anti-reflection coating of silicon nitride on said front surface, said anti-reflection coating having a front surface facing away from said substrate; a first aluminum-coating electrode affixed in mechanical and electrical contact with said rear surface; an array of narrow, elongate, substantially parallel second electrodes extending through said anti-reflection coating and affixed in mechanical and low resistance electrical contact with said front surface of said substrate, said second electrodes comprising silver particles in a glass matrix; and at least one third electrode overlying said front surface of said anti-reflection coating and extending across said array of second electrodes in spaced and non-contacting relation with said front surface of said substrate, said at least one third electrode comprising silver particles dispersed in an epoxy matrix and being bonded to said anti-reflection coating and said second electrodes.
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16. A solar cell comprising:
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a semiconductor substrate having a front surface, a rear surface, and a shallow p-n junction adjacent said front surface; a first electrode affixed in mechanical and electrical contact with said rear surface; an array of narrow, elongate, second electrodes affixed in mechanical and low resistance electrical contact with said front surface; an anti-reflection coating overlying and bonded to said front surface in flanking relation to each of said second electrodes, said anti-reflection coating having a front surface facing away from said substrate; and at least one third electrode comprising conductive metal particles in a solid epoxy polymer material, said third electrode being bonded to said front surface of said anti-reflection coating and extending across said array of second electrodes at an angle to each of said second electrodes, said third electrode being in direct electrical contact with each of said second electrodes and also being spaced from and out of contact with the front surface of said semiconductor substrate by portions of said anti-reflection coating. - View Dependent Claims (17, 18, 19)
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20. A method of making a solar cell, comprising:
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(a) providing a semiconductor substrate having a front surface, a rear surface, a shallow p-n junction adjacent said front surface, an anti-reflection coating overlying and bonded to said front surface, and a first electrode in mechanical and electrical contact with said rear surface; (b) forming an array of narrow, elongate, and mutually spaced second electrodes on said front surface of said semiconductor substrate such that each of said second electrodes is in mechanically adherent and low resistance electrical contact with said front surface of said semiconductor substrate and is flanked by said anti-reflection coating; and (c) affixing at least one elongate third electrode to said front surface of said anti-reflection coating and each of said second electrodes such that said at least one third electrode extends across said array of second electrodes and is displaced from said front surface of said semiconductor substrate by said anti-reflection coating, said third electrode being affixed to said anti-reflection coating by selectively coating said anti-reflection coating and portions of said array of second electrodes with an epoxy material containing conductive metal particles in the desired pattern, and thereafter curing the epoxy material. - View Dependent Claims (21)
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Specification