Friday night fun consisted of trying out solar cell tabbing. Most components for the solar cell has arrived and tonight when I finally got some “me time”, I wanted to test solar cell tabbing, It was the first time doing tabbing and it was quite straight forward. The solar panel for the Valify robot will consist of 3 groups with 40cells in each group (120 cells total). So tonight I Tried tabbing two rows and combined them with a BUS wire, making a total of 16 cells in serie.
The Solar cells I am using is 0.12W, 0.5V, 0.24A, 39x19mm from Aoshike. Over all they look good, but there are deviations.
So in order connect them in series you need to go from Top on the first cell to the bottom of next cell. The polarity is (Postive +) on the top and (negative -) at the bottom.
I started to do a couple of pairs tabbed together, Then adding a tabbing wire to bottom one pair and then adding it to “the first pair” and repeated this. The assembly with lot of cells I never touched more than adding the next pair. This because of the fragility of the cells.
The tabbing wire should always be a couple of millimeters shorter then two cells together + the space between the cells. This way a “short” can be avoided.
When doing the tabbing I am using a Dibotech soldering iron Pro 60 W with the ability to adjust the temperature. The temperature I had to regulate until the tabbing wire melted nicely, I was running at 370C. and with a very flat ironing tip.
Before soldering you need to flux the cells with a flux pen. The flux cleans the cells and also makes it easier for the tabbing wire to stick with the soldering to the cell. Also when soldering you should have a even flow movement on the hand and try to do the entire tabbing soldering at one stroke to avoid irregularities in soldering.
My soldering came out quite nicely, but for this first “test” I didn’t use any tools to get the cells aligned, So it looks like shit.
Tomorrow I will try my first test cells in direct sunlight (Hopefully there is some sun) and see how they can produce.
Next step here is to Design a alignment tool that I can 3D print and use to get the cells even and aligned. I think I will do that tomorrow, but I can’t print it because my printer is busy doing the first wheel to the robot.
Lets see how this continues, The tabbing was actually fun, a bit like a puzzle.