A New Technique for Soldering Solar Cells

General, Solar / Tuesday, February 13th, 2024

As we refine SOCKEYE for the 2024 Solar Car Challenge, the solar panel subteam has been experimenting with new, potentially more effective soldering strategies.

The use of our sponsor, Maxeon Sunpower’s solar cells is vital to the team, as they produce the industry-leading super-efficient silicon cells that make up the heart of the car. Throughout the history of the team, their generous support has lead to the successful assembly of each year’s handmade array.

Each fragile solar cell is connected to six soldering joints, and a failure or short with just one could affect the performance of the whole panel. Because of this, it’s vital to improve our soldering methods to make them more consistent, durable, and effective.

Since the beginning of our panel production, the team has used tinned dogbone connectors between the Maxeon Sunpower cells.  With this system, jigs are used to hold the dogbones in place, which are later removed once soldering is complete. Although this is the most common method, it tends to be quite tedious, and due to the limited space on each contact, there is significant room for mistakes. In the past, we’ve had issues with cell overlap, shorts from the dogbones, and the most pressing issue: the potato-chip like cells can get caught on the rigs and crack. 

This year we’ve been testing and refining a new method involving Kapton tape (a tape with high heat resistance), and copper strips. Using the laser cutters, each strip of tape is cut to the size of the contacts on each cell. The Tape blocks any potential shorts, and a strip of copper tape is soldered on top, connecting all 6 points. With this method, the stress and difficulty of removing each row from the jigs is eliminated, and short circuits are much less likely.

Plenty of work remains for the subteam, as we plan out our modifications to the car. This work includes testing last year’s array, further implementation/refinement of our new methods, and training new members, but we are looking forward to taking it on- such is the joy of solar car.

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