Metallic foil substrate and packaging technique for thin film solar cells and modules
OwnerBulent M. Basol, Mustafa Pinarbasiinventors
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Abstract
Methods of forming thin film solar cells with a metallic substrate are described, as well as solar cells and solar cells strings. The front surface of the metallic substrate is polished to form a polished front surface so that the average roughness of the polished front surface is less than 50 nm. The back surface of the metallic substrate is roughened to form a rough back surface so that the average roughness of the conditioned back surface is more than 500 nm. A Group IBIIIAVIA compound absorber layer is formed over the polished front surface.
Claims41
A method of forming a thin film solar cell, the method comprising:
- providing a metallic substrate such that a finished front surface of the metallic substrate has an average roughness of less than 50 nm and a conditioned back surface that has an average roughness of more than 200 nm;
- and
- forming a solar cell absorber layer over the finished front surface.
A method of manufacturing a solar module, comprising:
- forming a string of solar cells, wherein the string of solar cells include at least two solar cells, and each solar cell includes a light receiving stack with an exposed top surface and a conductive substrate having a rough back surface and a finished front surface over which the light receiving stack is formed, wherein the light receiving stack includes a Group IBIIIAVIA absorber layer, and wherein the average roughness of the rough back surface is more than 500 nm and the average roughness of the finished front surface is less 50 nm;
- bonding a back packaging layer to the rough back surfaces of the conductive substrates and a front packaging layer to the exposed top surfaces of the light receiving stacks of the solar cells respectively.
A method of attaching a contact lead to the back side of a solar cell structure, comprising
- laser treating a predetermined area of the back side of the solar cell structure forming a treated back surface area;
- and
- attaching the contact lead to the treated back surface area.
A solar cell, comprising:
- a conductive substrate having a front surface and a back surface including roughness, wherein the average roughness of the back surface is more than 500 nm and the average roughness of the front surface is less than 50 nm;
- and
- a Group IBIIIAVIA absorber layer formed over the front surface.
A solar cell module, comprising:
- a string of solar cells including at least two solar cells, wherein each solar cell includes a light receiving stack with an exposed top surface and a conductive substrate having a rough back surface and a finished front surface over which the light receiving stack is formed, wherein the light receiving stack includes a Group IBIIIAVIA absorber layer, and wherein the average roughness of the rough back surface is more than 500 nm and the average roughness of the finished front surface is less than 50 nm;
- a back packaging layer bonded to the rough back surfaces of the conductive substrates;
- and
- a front surface packaging layer bonded to the exposed top surfaces of the light receiving stacks.
Dependencies are inferred from the claim text.