Multi-junction PV module
A photovoltaic device is provided which includes a plurality of junction layers. Each junction layer includes a plurality of photovoltaic cells electrically connected to one another. At least one of the junction layers is at least in part optically transmissive. The junction layers are arranged in a stack on top of each other.
1. A photovoltaic device comprising
a plurality of junction layers, each of said plurality of junction layers comprising a plurality of photovoltaic cells electrically connected to one another, wherein each of said plurality of junction layers includes its own substrate on which the plurality of photovoltaic cells is disposed;
at least one of said plurality of junction layers being at least in part optically transmissive; and
said plurality of junction layers arranged in a stack on top of each other, at least two of said substrates being separated from one another by a junction layer.
2. The photovoltaic device of claim 1 wherein each of said junction layers comprises at least one pair of electrical terminals for receiving photogenerated current.
3. The photovoltaic device of claim 1 wherein said junction layers are manufactured separately on separate substrates.
4. The photovoltaic device of claim 1 wherein said junction layers are laminated to each other.
5. The photovoltaic device of claim 1 wherein said junction layers are produced on a common substrate.
6. The photovoltaic device of claim 1 wherein said junction layers are electrically insulated from each other.
7. The photovoltaic device of claim 1 wherein said plurality of junction layers comprises at least first and second junction layers, the first junction layer being configured to absorb a first portion of incident light energy and transmit a second portion of the incident light energy to the second junction layer, the second junction layer being configured to absorb at least a portion of the second incident light energy.
8. The photovoltaic device of claim 7 wherein said first junction layer comprises photovoltaic cells with a characteristic bandgap that is larger than that of cells in said second junction layer.
9. The photovoltaic device of claim 1 wherein a number of said photovoltaic cells in at least two of the junction layers are chosen so that their respective output voltages are about equal.
10. The photovoltaic device of claim 1 wherein a number of said photovoltaic cells in at least two of the junction layers are chosen so that their respective output currents are about equal.
11. The photovoltaic device of claim 2 wherein at least two of the junction layers are electrically connected in parallel.
12. The photovoltaic device of claim 2 wherein at least two of the junction layers are electrically connected in series.
13. The photovoltaic device of claim 1 wherein the photovoltaic cells in at least one of the junction layers is based on CIGS alloys.
14. The photovoltaic device of claim 1 wherein the photovoltaic cells in at least one of the junction layers is based on CdTe alloys.
15. The photovoltaic device of claim 2 further comprising electrical leads connected to said electrical terminals.
16. The photovoltaic device of claim 1 wherein the photovoltaic cells in each junction layer are electrically connected to one another in series.