Photovoltaic module interconnect joints
Photovoltaic (PV) cells that can be interconnected with improved interconnect joints to form PV cell strings and PV modules. The improved interconnect joints comprise at least two types of adhesive bonding regions to maximize both electrical conductivity and mechanical strength of interconnect joints coupling terminals of PV cells. The disclosed approaches to PV cell interconnection provide greater manufacturing rates and higher quality PV cell strings and PV modules.
1. A photovoltaic (PV) device comprising:
a plurality of PV cells having two opposite peripheral edges with a first surface there between, each PV cell comprising:
a plurality of discrete contact pads on the first surface and extending along a first of the two peripheral edges;
a plurality of discrete electrically conductive bonding material regions, each in physical and electrical contact with one of the plurality of discrete contact pads on the first surface;
a plurality of discrete electrically non-conductive bonding material regions on the first surface and extending along the first peripheral edge in locations between the plurality of discrete contact pads, wherein each of the discrete electrically non-conductive bonding material regions is discontinuous with one another, and wherein ones of the plurality of discrete electrically non-conductive bonding material regions are not in contact with ones of the plurality of discrete electrically conductive bonding material regions, and wherein the plurality of PV cells are connected in a shingled arrangement such that the first peripheral edge of one of the plurality of PV cells overlaps a second peripheral edge of an adjacent PV cell to form an interconnect bond line comprising the plurality of discrete electrically conductive bonding material regions and the plurality of discrete electrically non-conductive bonding material regions.
2. The PV device of claim 1 , wherein the plurality of discrete electrically conductive bonding material regions are substantially aligned with the plurality of discrete electrically non-conductive bonding material regions.
3. The PV device of claim 1 , wherein the plurality of discrete electrically conductive bonding material regions are offset from the plurality of discrete electrically non-conductive bonding material regions.
4. The PV device of claim 1 , wherein each of the plurality of discrete electrically conductive bonding material regions alternate with each of the plurality of discrete electrically non-conductive bonding material regions such that bonding regions of the same type are not directly adjacent.
5. The PV device of claim 1 , wherein two or more of the plurality of discrete electrically conductive bonding material regions are directly adjacent.
6. The PV device of claim 1 , wherein two or more of the plurality of discrete electrically non-conductive bonding material regions are directly adjacent.
7. The PV device of claim 1 , wherein two or more of the plurality of discrete electrically conductive bonding material regions alternate with two or more of the plurality of discrete electrically non-conductive bonding material regions.
8. The PV device of claim 1 , wherein each of the discrete electrically conductive bonding material regions substantially entirely cover one of the plurality of discrete contact pads.
9. The PV device of claim 1 , wherein the electrically conductive bonding material regions comprise an electrically conductive adhesive including a resin and metallic particles.
10. The PV device of claim 9 , wherein the resin comprises a material selected from the group of epoxies, acrylates, silicones, imides, bismaleimides, their derivatives and copolymers thereof.
11. The PV device of claim 9 , wherein the metallic particles are selected from the group of silver, nickel, tin, zinc, copper, gold, aluminum, iron, titanium, palladium, platinum and alloys thereof.
12. The PV device of claim 1 , wherein the electrical resistance of the electrically conductive bonding material regions is less than 10 −2 ohms-cm.
13. The PV device of claim 1 , wherein the Young's modulus of the electrically non-conductive bonding material regions is greater than 5 MPA.
14. The PV device of claim 1 , wherein the electrically non-conductive bonding material regions comprise an adhesive material selected from the group containing: epoxies, silicones, vinyl acetates, polyolefins, polyimides, acrylates, polyurethanes, cyanoacrylates, phenolics, and their derivatives and any combination thereof.
15. The PV device of claim 1 , wherein the interconnect bond line has a thickness throughout its width greater than 10 μm.