Electrical Characteristics Analysis of Bonded Cells for Shingled Modules.

Area of Science:

• Materials Science
• Photovoltaics
• Semiconductor Device Fabrication

Background:

• Shingled solar modules offer higher power than conventional ones by maximizing light-receiving area.
• Electrically conductive adhesive (ECA) is a promising alternative to traditional solder ribbons.
• Challenges include laser cutting damage and conductive paste contact issues.

Purpose of the Study:

• To investigate the fabrication of shingled crystalline silicon (c-Si) solar modules using ECA.
• To optimize laser cutting parameters for c-Si cells.
• To determine optimal ECA bonding conditions for maximum module efficiency.

Main Methods:

• Fabrication of 15.675 × 3.1 cm² c-Si cut cells using a nanosecond green laser.
• Optimization of laser cutting depth (approx. 46 μm, >25% wafer thickness).
• ECA bonding of cut cells with varying curing time and temperature.

Main Results:

• Optimal bonding conditions: 60s curing time at 150°C.
• Achieved highest cell efficiency of 20.27%.
• Efficiency increased by ~2.67% compared to conventional cells due to reduced busbar shadow loss.

Conclusions:

• Laser cutting requires sufficient depth (>25% wafer thickness) for effective cell fabrication.
• Optimized ECA bonding significantly enhances solar module efficiency.
• Eliminating busbars increases the active area, boosting overall module performance.