While it may be best known for making consumer electronics and household appliances, LG also boasts a formidable legacy in industrial manufacturing dating back almost to its creation in the middle of last century. That experience has been distilled into the development of a new breed of solar cell that ups the ante on harvesting sun power.
The model detailed in one of the company’s latest filings is about standard as they come with the exception of the electrodes attached on the bottom to carry the generated electricity to the grid, which are made up of two distinct layers. The main highlight is the reflective upper part that connects to the photoelectric surface:
The specific implementation represented in 422a is an alloy of native metals applied in a thickness of 50 to to 300 nanometers depending on the configuration. And the adhesive that fixes the electrodes to the cell is in turn a layer of titanium or tungsten at least 20 times as thin, a ratio that allows for transparency.
That enables light that doesn’t get immediately absorbed into the solar cell to be reflected back into the photoelectric conversion unit – which in this particular case is made out of standard crystalline silicon – from the electrode. This increases the efficiency of the power generation process, one of the biggest hurdles standing in the way of solar power from displacing more economic traditional sources.
The diagram compares how configurations with adhesive thickness ranging from 10 to 200 nanometers match up against a control cell (Comparative Example 1) that doesn’t have anything separating the electrode from the silicon. That the reflectiveness decreases as the amount of sealant grows suggests any products LG will base on the patent will be on the thinner end.
Capturing unused light is not the only benefit of the company’s approach, however: the adhesive’s coefficient of thermal expansion – the rate at which its size changes with temperature – is between that of the photoelectric unit on top and the electrode below. That acts to reduce the difference between the layers, thereby making the whole better in dealing with the heat of the warm, sunny places where solar panels are typically placed.