Point Back Contact Silicon Photovoltaic Solar Cells with Electroplated Aluminum Electrodes

Description

Solar energy is becoming relevant for global electricity production. Electrons are collected from silicon wafers through metal grid lines, typically made of silver, which convert transfer energy to the power transmission grid. Silver is highly conductive and has very low resistivity, making it an optimal material for this purpose. Limited silver reserves drive up the cost of this material. Researchers are looking for an inexpensive, earth-abundant material to replace silver. Copper has been examined because of its extremely low resistivity, but has detrimental performance issues when it comes into contact with silicon. Expensive boundary layers are required to overcome these issues. Researchers have also examined aluminum. This material is inexpensive and does not have detrimental reactions with silicon, but has historically necessitated a prohibitively expensive manufacturing process. Advancements to the manufacturing process have made aluminum a viable choice, but efficiency could still be improved.

Researchers at ASU have discovered a way to use aluminum electroplating to employ point contact for the electrode which significantly improves the efficiency of the solar cells. Aluminum is an abundant, inexpensive material. It remains stable when applied to silicon, eliminating the expensive coatings needed when copper is used. Electroplating aluminum onto the front end of solar panel grid lines cell can be done at low temperatures, making the manufacturing process less expensive. The backside of the grid lines are made of screen-printed aluminum, allowing point contact for the backside electrode. Point contact increases the power conversion efficiency. The cost of silicon solar modules is expected to be reduced by 10%; savings will increase as dwindling reserves further drive up the cost of silver.

Potential Applications

  • Solar Energy
  • Silicon Solar Cells
  • Light Emitting Diodes
  • Integrated Circuits

Benefits and Advantages

  • Lower Costs – Cost of producing solar cells is reduced by a projected 10% while maintaining efficiency above an estimated 15%.
  • Large Scale - Enables terawatt-scale deployment of wafer-silicon solar cells at an affordable price.
  • Manufacturability - Requires a simpler cell fabrication process because neither a barrier layer nor a protective layer is needed.
  • Longevity - Increased resistance to oxidation/moisture increases the lifetime of panels and lessen requirements for air and moisture tightness for modules, further reducing cost.
  • Versatility - Panels are better suited for deployment in humid climates.
  • Retrofit - Process can be applied to existing solar cell production facilities.

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Case ID:
M14-245P
Published:
06-17-2015
Last Updated:
06-06-2018

Inventor(s):

Meng Tao

Patent Information

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