Solar cell panel
A solar cell panel includes a first solar cell and a second solar cell; and a plurality of leads connecting the first solar cell and the second solar cell. Each of the first solar cell and the second solar cell includes: a first electrode including a plurality of finger lines in a first direction and a plurality of first bus bars in a second direction crossing the first direction; and a second electrode including a plurality of second bus bars in the second direction. The plurality of leads have a diameter or width of 100 to 500 μm, and include 6 or more leads arranged at one surface side of the first or second solar cell. The plurality of leads are connected to the plurality of first bus bars of the first solar cell and the plurality of second bus bars of the second solar cell by a solder layer, respectively.
1. A solar cell panel comprising:
a plurality of solar cells comprising at least a first solar cell and a second solar cell; and
a plurality of leads to connect the first solar cell and the second solar cell,
wherein each of the first solar cell and the second solar cell comprises:
a semiconductor substrate;
a first passivation layer on a front surface of the semiconductor substrate;
a second passivation layer on a back surface of the semiconductor substrate;
a first conductivity type region on the first passivation layer at the front surface of the semiconductor substrate;
a second conductivity type region on the second passivation layer at the back surface of the semiconductor substrate;
a first electrode electrically connected to the first conductivity type region, the first electrode comprising a first metal electrode layer including a plurality of finger lines in a first direction and a plurality of first bus bars in a second direction crossing the first direction; and
a second electrode electrically connected to the second conductivity type region, the second electrode comprising a second metal electrode layer including a plurality of second bus bars in the second direction,
wherein the plurality of leads have a diameter or width of 100 to 500 μm, and comprise 6 or more leads arranged at one surface side of the first or second solar cell,
wherein each of the plurality of leads comprises a core layer having a circular, oval or round shape and a solder layer coated on the entire outer surface of the core layer,
wherein the plurality of leads are connected to the plurality of first bus bars of the first solar cell and the plurality of second bus bars of the second solar cell by the solder layer, respectively,
wherein the solder layer includes a portion adjacent to the first or second electrode, and
wherein a width of the portion gradually increases toward the first or second electrode.
2. The solar cell panel according to claim 1 , wherein the first conductivity type region includes a front surface field region having a conductivity type the same as that of the semiconductor substrate with a higher doping concentration than the semiconductor substrate, and
wherein the second conductivity type region includes an emitter region having a conductivity type opposite to that of the semiconductor substrate.
3. The solar cell panel according to claim 1 , wherein the portion of the solder layer has a concave shape with respect to an outside of the solar cell.
4. The solar cell panel according to claim 1 , wherein the plurality of first bus bars or the plurality of second bus bars include a pad portion having a width larger than a width of the solder layer, and
wherein the solder layer is formed only on a surface of the pad portion opposite to the semiconductor substrate, and is not formed on a side surface of the pad portion.
5. The solar cell panel according to claim 1 , wherein at least one of the first and second metal electrode layers includes a metal and a cross-linking resin.
6. The solar cell panel according to claim 5 , wherein an amount of the metal is greater than an amount of the cross-linking resin in the first or second metal electrode layer.
7. The solar cell panel according to claim 6 , wherein the metal is included by 80 to 95 parts by weight and the cross-linking resin is included by 5 to 20 parts by weight, with respect to 100 parts by weight of a sum of the metal and the cross-linking resin in the first or second metal electrode layer.
8. The solar cell panel according to claim 5 , wherein the first or second metal electrode layer does not include a glass frit.
9. The solar cell panel according to claim 5 , wherein the cross-linking resin includes at least one of a phenoxy-based resin, an epoxy-based resin, and a cellulose-based resin.
10. The solar cell panel according to claim 5 , wherein the metal includes first-shaped particles and second-shaped particles having different shapes from each other.
11. The solar cell panel according to claim 10 , wherein the first-shaped particles have a spherical shape and the second-shaped particles have a non-spherical shape, and
wherein an amount of the first-shaped particles is greater than an amount of the second-shaped particles.
12. The solar cell panel according to claim 10 , wherein at least a part of the second-shaped particles has a size greater than a thickness of the solder layer.
13. The solar cell panel according to claim 10 , wherein the first-shaped particles have a spherical shape having a diameter of 0.1 to 5 μm, and the second-shaped particles have a flake shape having a long width of 2 to 10 μm and a thickness of 0.2 to 5 μm.
14. The solar cell panel according to claim 5 , wherein the metal includes first particles and second particles having different sizes from each other.
15. The solar cell panel according to claim 1 , wherein a porosity of the first or second metal electrode layer is higher than a porosity of the solder layer.
16. The solar cell panel according to claim 1 , further comprising:
a barrier electrode portion positioned on the first or second metal electrode layer and having a metal amount greater than a metal amount of the first or second metal electrode layer.
17. The solar cell panel according to claim 16 , wherein at least one of the first and second electrodes includes a transparent electrode layer between the first or second conductivity type region and the first or second metal electrode layer,
wherein the barrier electrode portion is disposed on at least one of a first surface of the first or second metal electrode layer facing the transparent electrode layer, a second surface of the first or second metal electrode layer opposite to the first surface of the first or second metal electrode layer, and a side surface of the first or second metal electrode layer, and
wherein the barrier electrode portion has a shape of a layer or particles.
18. The solar cell panel according to claim 1 , wherein the semiconductor substrate has a crystalline structure, and
wherein at least one of the first and second conductivity type regions has an amorphous structure.
19. The solar cell panel according to claim 18 , wherein each of the first and second conductivity type regions includes amorphous silicon, and
wherein each of the first and second passivation layers includes an intrinsic amorphous silicon.
20. The solar cell panel according to claim 1 , wherein the solder layer includes an inflection point where a curvature varies at a side surface of the solder layer.