Anx2k
Solar Enthusiast
I've been working on a 3D printed battery bracket for EVE 280-320AH prismatic cells - I had originally been using some of the Chinese ones that I had sourced on Alibaba, but the more I worked with them the less happy I was with them, so decided to give it a shot with my handy Bambu X1C. I originally printed them with PLA, but then switched it up to PETG, although either should work fine so you can pick whichever you're more comfortable with. In terms of material costs, depending on how much you pay, each bracket ends up being about $1 of material - which was about what I was getting the Chinese ABS brackets for (in quantity), but that doesn't include shipping, which makes these considerably cheaper. That $1 price assumes you're paying around $16 for a 1kg spool, and I've been looking to do a larger Alibaba PETG order, so if you were printing a bunch I could easily see that being 1/2 that (keep in mind this is just raw material costs, not time, etc. Each one takes about 1.5 hours to print with my tuned X1C profile, and it takes a total of 16x of these to do a 24v pack or 32x for a 48v pack.
Now, why I did I end up redesigning this? It really came down to some ways I felt like the ABS design could be improved - the first area was how they interlocked. On the ABS one, they had little nubs that clicked together, but I had these break before, which makes the bracket useless. For my design, I replaced this with a 2mm x 16mm stainless steel dowel (100x cost about $7 on Amazon), and it uses one on each corner to lock them together. There's 8mm inserted on each side, so they really hold things together well. It's a loose friction fit, as when it's assembled it's meant to be held together with fiber reinforced strapping tape (as was the original bracket).
Next, the ABS design had one end plate, and a different middle plate - while not a big deal, it was a pain when you ran out of ends but still had middles - so with my design, there's only a single one, and they just connect either back to back or front to front. This also is advantageous on the 3D printing side, as I didn't want to use any support material, and this way everything works and the overhangs (for cutouts) are small enough to just bridge.
While the ABS one did somewhat lock horizontally together, it was kind of poor (in my experience), and also made the overall pack size slightly larger for no real reason. One mine, I have alternating cutouts on all corners, top and bottom, so that each bracket locks in with the one next to it with two contact points - one going into the neighboring part, one going in from the neighboring part. This makes a much stronger side connection than I had before.
The ABS used fiber reinforced strapping tape to hold it together once assembled, and I actually quite like this so I stole that design element.
I go around the pack twice so the tape locks to itself, and do this at the top and bottom. It's not really meant to hold the pack together, but more just to ensure it doesn't fall apart. You'd still want to have it either resting on something or mechanically constrained in some manner.
Finally, there was really no rhyme or reason I could figure out for how they put some of their supports or bracket spots, and most of the things I build are using 80/20, so this is designed to work with their 15 series extrusion. This means that it will 'lock' into the channel in the extrusion, both helping to really keep packs together - on both the bottom and the top. On the top I added extra blocking and thicker ones so that it makes extra contact with the enclosure, since this is on the top and between the cell posts, and obviously you wouldn't want the 80/20 to get anywhere near the posts. The bracket works fine without 80/20 though, so don't think you need to use it - it just has features that are nice is you do.
Anyway, here's some photos to get an idea of how it all looks, and I'm just waiting on it being approved on the 3D printing side for the posted STL file, and I'll post that when they do. You should be able to print it with pretty much any 3D printer, as long as you have a print area large enough for it - but most of the normal 3D printers around do (not the mini's).
Now, why I did I end up redesigning this? It really came down to some ways I felt like the ABS design could be improved - the first area was how they interlocked. On the ABS one, they had little nubs that clicked together, but I had these break before, which makes the bracket useless. For my design, I replaced this with a 2mm x 16mm stainless steel dowel (100x cost about $7 on Amazon), and it uses one on each corner to lock them together. There's 8mm inserted on each side, so they really hold things together well. It's a loose friction fit, as when it's assembled it's meant to be held together with fiber reinforced strapping tape (as was the original bracket).
Next, the ABS design had one end plate, and a different middle plate - while not a big deal, it was a pain when you ran out of ends but still had middles - so with my design, there's only a single one, and they just connect either back to back or front to front. This also is advantageous on the 3D printing side, as I didn't want to use any support material, and this way everything works and the overhangs (for cutouts) are small enough to just bridge.
While the ABS one did somewhat lock horizontally together, it was kind of poor (in my experience), and also made the overall pack size slightly larger for no real reason. One mine, I have alternating cutouts on all corners, top and bottom, so that each bracket locks in with the one next to it with two contact points - one going into the neighboring part, one going in from the neighboring part. This makes a much stronger side connection than I had before.
The ABS used fiber reinforced strapping tape to hold it together once assembled, and I actually quite like this so I stole that design element.
I go around the pack twice so the tape locks to itself, and do this at the top and bottom. It's not really meant to hold the pack together, but more just to ensure it doesn't fall apart. You'd still want to have it either resting on something or mechanically constrained in some manner.Finally, there was really no rhyme or reason I could figure out for how they put some of their supports or bracket spots, and most of the things I build are using 80/20, so this is designed to work with their 15 series extrusion. This means that it will 'lock' into the channel in the extrusion, both helping to really keep packs together - on both the bottom and the top. On the top I added extra blocking and thicker ones so that it makes extra contact with the enclosure, since this is on the top and between the cell posts, and obviously you wouldn't want the 80/20 to get anywhere near the posts. The bracket works fine without 80/20 though, so don't think you need to use it - it just has features that are nice is you do.
Anyway, here's some photos to get an idea of how it all looks, and I'm just waiting on it being approved on the 3D printing side for the posted STL file, and I'll post that when they do. You should be able to print it with pretty much any 3D printer, as long as you have a print area large enough for it - but most of the normal 3D printers around do (not the mini's).
