Cutting Supower Maxeon Solar Cells? - Mikes Inventions

mikesinventions.etsy.com I was asked if it was possible to cut Sunpower's Maxeon solar cells. Here's what I found out...
Voltage essentially stays the same, but it's only going to generate half the power, because they can only put out half the amps.

[@1kreature]

That was butchery!
Interesting video, but not a good way to cut the cells.
First off, the cells have 3 sets of contacts on each side with a intervoven set of copper traces connecting all the area to the two sides.
One half of these lines connect to the backside directly, and the other have tiny vias or doped regions through the cell to contact the opposite face.
I found the best and easiest cuts are to split the cell into 3. Due to the different areas you get on the top and bottom vs middle cut I found a approximately 42mm width on each side leaves you with a 41mm strip in middle. This offsets the corners so each strip produce same ammount of power.
To actually cut the cells, it is best to use a very sharp carbide tip and do the same as you would when cutting glass. That is, without too much pressure, score the cell along a steel ruler. This produces minimal ammounts of dust and if done right will not crack the cell except along the scoreline.
Once done a light bend will snap the cell along the score. The back copper will still be connecting the pieces so this has to be cut carefully with a scalpel or other tool.
Cutting through the pads can be done if one needs much smaller strips (for example to increase voltage further) but it is harder and will not leave equal sized areas.
I make small 4, 6 and 8 piece panels with this method and they seem very durable.
I bond the cells to glass using EVA film both between the glass and cells, and to bond a backing material.
Looking at the pattern of copper on the back of the cells, I experimented with making small pcb's that would allow attaching very small pieces of cells to them. The boards join up the strands along edges of cell pieces by peeling off some cell material on the edges, keeping the copper traces. This also worked and allowed me to create pcb's with 10 and 12 small solar cell pieces on the back for 5v supply. (On a 50x50mm square board.)
So, yes, Maxeon C60 cells are cuttable, trimmable and very diy-able!

[@68HC060]

A very valuable comment, thank you!

[@fireofenergy]

Thanks for the info. I'm trying to charge up the ole single nimh (probably a few in parallel) and 2v is two much, but 1.5 from normal solar cells seemed to not be enough, this the reason I'm interested in these cells. I figure 1 cut into 3 would be perfect...
And they do have that little extra voltage to them, don't they?

[@qualityparts2765]

have you worked with solar wafers that seem to have 4 quadrants at the back? would you know how to wire them

[@leveckfamily8841]

Can you try an abrasive wheel or a glass cutter? I would think if you used a blade on the back to lightly cut through the traces and then a glass cutter to score and snap it through the front face, with some practice, it might work.
Or the same technique with an abrasive wheel on a Dremel. Or maybe even a tile saw if you can lower the blade enough to just cut through the glass side. Tile saw HATE paper and would probably mess up the electrical traces on the bottom of the panel....

[@jordanpowell1792]

This is the correct solution...I've cut my own solar panels in the past with a dremel and cutting wheel (diamond grit is best but aluminum oxide works too).
I built a jig that allowed my dremel to function similar to a tiny table saw and gently fed the panels through so they were all the same size with a perfectly straight line.

[@christopherleveck6835]

@@jordanpowell1792 wish I had seen this before I reinvented the wheel so to speak. The important thing is that we all manage to cross the finish line. I wish we could all do it together sometimes though......
I am building several small solar only powered aircraft and one great big one.
The issue with the smaller drones is that I don't have the wing area to mount the full-size cells. Can I still need to make voltage so being able to split the cells which I am doing in 3 by the way makes it possible for me to get the voltage I need even though I lose the milliamps it's not that big a deal because it's a small motor after all.....
Well it would have been nice to get the information from me before I tried it it is nice to get the validation now that I'm done so I appreciate your response. Thank you.

[@bobhilder1469]

I have a friend that's a solar module fab engineer and he uses this video to teach people how NOT to cut solar cells.

[@williamfraser]

What method does your friend prefer?

[@bobhilder1469]

@@williamfraser My fried prefers to use "dicing saws". Conventionally, dicing saws are used, among other things, to cut silicon wafers. The SunPower/Maxeon solar cells are, in effect, single crystal silicon wafers with quite a bit of copper added on the back. I'm happy to expound if you'd like.

[@xsirfr1958]

Mike - Voltage is NOT power! As a figure of merit, you should measure both Voc and Isc.

[@Techmoody123]

It's like paper but i have glass type cell just broken it if I try like this

[@RandomSmith]

I guess you are getting the same voltage because you have the same number of inner cells, the cells are half the length rather than cutting the other orientation which would half the number of cells and probably just under half the voltage. Total power generated would be less because the current from half a cell would be less.

[@toxomanrod]

RandomSmith Would you say that cutting a cell in half keeps the voltage the same on the two pieces, but halves the current? So if I split one cell, I could have two 0.5V cells in series to make 1V at half the current (ideally)?

[@RandomSmith]

Nathan Martinez, making an educated guess - if you have one cell before a cut and two half cells after a cut, the total power would still be the same overall. So a 1 cell 0.5v panel cut in half across the panel would have two 0.5v cells and those in series would make 1v cell so the current would most likely be roughly half accounting for partial damage to the cell to keep the total power the same.

[@1kreature]

@@toxomanrod Yes.
The only limit to ammount of pieces and increase in voltage is the copper pattern on the back.
It is only practical to cut it in such a way as to keep the pattern intact as it is what is conducting the current out from the PN junction.
No matter how small the shard, it will still produce the same voltage, only less current.

[@philthayer4087]

Power will be same, current will be half.

[@bobhilder1469]

Because power is the product of voltage and current and voltage stays the same, power will be half if current is half.