Integrated method and system for manufacturing monolithic panels of crystalline solar cells
A method for fabricating a photovoltaic (PV) cell panel wherein all PV cells are formed simultaneously on a two-dimensional array of monocrystalline silicon mother wafers affixed to a susceptor is disclosed. Porous silicon separation layers are anodized in the surfaces of the mother wafers. The porous film is then smoothed to form a suitable surface for epitaxial film growth. An epitaxial reactor is used to grow n- and p-type films forming the PV cell structures. Contacts to the n- and p-layers are deposited, followed by gluing of a glass layer to the PV cell array. The porous silicon film is then separated by exfoliation in a peeling motion across all the cells attached together above, followed by attaching a strengthening layer on the PV cell array. The array of mother wafers may be reused multiple times, thereby reducing materials costs for the completed solar panels.
1. A solar panel fabrication method, comprising:
simultaneously thermally smoothing surfaces of porous silicon layers, said porous silicon layers being on the surfaces of a plurality of substrates, said plurality of substrates being attached to a susceptor;
simultaneously forming a photovoltaic (PV) cell on each substrate of said plurality of substrates, said PV cells being formed on said thermally smoothed surfaces; and
simultaneously forming electrical contacts on each of said PV cells.
2. The method of claim 1 , further comprising simultaneously forming said porous silicon layers on said plurality of substrates.
3. The method of claim 2 , wherein said simultaneously forming said porous silicon layers comprises anodization in a liquid electrolyte.
4. The method of claim 3 , wherein said substrates are attached to said susceptor during said simultaneously forming said porous silicon layers.
5. The method of claim 1 , wherein said simultaneously forming electrical contacts includes:
simultaneously forming a patterned contact precursor on each of said PV cells attached to said susceptor;
depositing a handling layer precursor on each of said PV cells attached to said susceptor, said handling layer precursor covering said patterned contact precursor; and
simultaneously heating said plurality of substrates attached to said susceptor to sinter said patterned contact precursor to said PV cells and to thermally convert said handling layer precursor into handling layers on said plurality of substrates, said handling layer not bridging neighboring ones of said PV cells.
6. The method of claim 1 , further comprising:
depositing a glue layer across all of said PV cells, said glue layer bridging neighboring ones of said PV cells;
thermally bonding said glue layer to said PV cells; and
exfoliating said PV cells from each of said plurality of substrates, said PV cells remaining attached to said glue layer.
7. The method of claim 6 , further comprising:
simultaneously texture etching said exfoliated surfaces of said PV cells; and
simultaneously depositing an anti-reflective coating on said texture etched exfoliated surfaces of said PV cells.
8. The method of claim 6 , further comprising, before said exfoliating, attaching a support layer to said glue layer.
9. The method of claim 6 , further comprising removing the remnants of said porous silicon layers from exfoliated surfaces of said PV cells.
10. The method of claim 1 , wherein said simultaneously forming electrical contacts includes screen printing.
11. The method of claim 1 , further comprising:
depositing a handling layer precursor on each of said PV cells attached to said susceptor; and
simultaneously heating all of said plurality of substrates attached to said susceptor to thermally convert said handling layer precursor into handling layers on all of said plurality of substrates, said handling layer not bridging neighboring ones of said PV cells.
12. The method of claim 1 , further comprising attaching metal stringers to said electrical contacts.
13. The method of claim 1 , wherein said simultaneously forming a photovoltaic (PV) cell on each substrate of said plurality of substrates includes chemical vapor deposition.
14. The method of claim 1 , wherein said PV cells include n-type and p-type silicon layers.
15. The method of claim 1 , wherein said simultaneously forming electrical contacts is a thin film process.
16. The method of claim 1 , wherein said simultaneously forming electrical contacts is a thick film process.
17. The method of claim 1 , wherein said porous silicon layers comprise a low porosity layer over a high porosity layer.
18. The method of claim 1 , wherein said porous silicon layers cover the entire top surfaces of said plurality of substrates attached to said susceptor.