Solar cell lead wire and production method therefor and solar cell using same

1. A solar cell lead wire, comprising:

a strip-shaped conductive material formed by rolling a wire with a circular cross section; and

upper and lower melt solder-plated layers comprising flat upper and lower surfaces, respectively, of the strip-shaped conductive material by supplying melt solder thereto.

2. The solar cell lead wire according to claim 1 , wherein the strip-shaped conductive material comprises a rectangular wire whose volume resistivity is not more than 50 μΩ·mm.

3. The solar cell lead wire according to claim 1 , wherein the strip-shaped conductive material comprises one of Cu, Al, Ag and Au.

4. The solar cell lead wire according to claim 1 , wherein the strip-shaped conductive material comprises one of a tough pitch Cu, a low oxygen Cu, an oxygen-free Cu, a phosphorous deoxidized Cu, and a high purity Cu whose purity is not less than 99.9999%.

5. The solar cell lead wire according to claim 1 , wherein the melt solder-plated layers comprise a Sn-based solder or a Sn-based solder alloy containing Sn as a first component, and not less than 0.1 mass % of at least one element selected from Pb, In, Bi, Sb, Ag, Zn, Ni, and Cu, as a second component.

6. A solar cell, comprising:

the solar cell lead wire according to claim 1 ; and

a semiconductor substrate comprising frontside and backside electrodes,

wherein the solar cell lead wire is soldered to the frontside and backside electrodes of the semiconductor substrate with the solder of the melt solder-plated layers.

7. The solar cell lead wire according to claim 1 , wherein the strip-shaped conductive material comprises the wire with the circular cross section.

8. The solar cell lead wire according to claim 1 , wherein said flat upper and lower surfaces of the upper and lower melt solder-plated layers respectively extend from an edge of the upper and lower melt solder-plated layers to another edge of the upper and lower melt solder-plated layers.

9. The solar cell lead wire according to claim 1 , wherein a thickness of the lower melt solder-plated layer is at least 5 μm at both ends.

10. The solar cell lead wire according to claim 1 , wherein a thickness at both ends of the lower melt solder-plated layer is specified in a predetermined range, and

wherein the lower surface thereof is depressed.

11. A production method for a solar cell lead wire, said method comprising:

rolling a wire with a circular cross section to thereby form a strip-shaped conductive material;

heating the strip-shaped conductive material in a continuous current heating furnace, a continuous heating furnace, or a batch-type heating equipment;

subsequently supplying melt solder to solder-plate the strip-shaped conductive material; and

sandwiching the plated strip-shaped conductive material between rolls to thereby form flat melt solder-plated layers.

12. The method according to claim 11 , wherein a thickness of one of the melt solder-plated layers, which is disposed on a lower surface of the strip-shaped conductive material, is at least 5 μm.