Some people here have shared their ideas for 3D printed battery cell holders (e.g. NESE & @Winfly’s compression pack) and also there are people who print their enclosures. I thought why not combine the two.
This is my idea of a single 3D printed part which serves as an enclosure and houses a 10S3P battery, no spot welding required. It uses the NESE tabs to connect the cells and to provide the compression for the contacts.
The size of the part is a little under 200 x 200 mm and so could be printed with almost any 3D printer. This is also the reason why I chose 3P configuration. The outer dimensions of the part are roughly the same as an Ownboard enclosure which only holds a 2P battery.
Cells don’t need any soldering and can be swapped when needed. The part was designed 3D printing in mind and so it prints in one piece and doesn’t need supports.
This particular enclosure is designed to fit a Loaded Vanguard. I’ve yet to decide how to mount the part to the deck but I’m leaning towards to embed some inserts to the enclosure and bolt it down from the top of the deck.
The grooves behind some of the tabs are for routing BMS wires. Two larger grooves on the sides are needed to connect two 3P tabs together by soldering some large gauge wire between them.
I’m also thinking to make some kind of a lid to separate the BMS area from the cells. Something like this:
At the moment I’m not sure if and when I’m going to print and test this. Just thought to share my idea and maybe get some constructive criticism from you guys.
If I were to print it I would use Colorfabb XT (clear) which is the most durable filament I’ve ever used that is still very easy to print. I’m sure there are some forces from the battery compression and so the part has to be able to take it without cracking. I made sure there’s a lot of material around the cells in the design.
Thanks for the input. NESE tabs come with a compressive material, I was lazy and did not model that.
I share the worry about the cells in the middle section. This problem could be helped with some cross supports like in the pic below. Unfortunately adding more of those would block access to the lower cells.
I printed a test part to see how the supports look in real life and to get some idea if the tolerances are good. I don’t have the tabs so couldn’t test how they fit. However the part feels very rigid and I think this project could be very doable.
@mishrasubhransu I’m using a DIY CoreXY printer, quite similar to Hypercube. 0.6 mm nozzle on the E3D Volcano and 0.4 mm layer height. Larger nozzle also provides more strength in the part.
@Jasonkimberson I don’t think that would be a problem at least during normal operating conditions, except if PLA was used. Plus the NESE modules have been around for a while and they are 3D printed. Anyway the filament I’m using doesn’t like to print well under 240 degC (Colorfabb XT).
I do think that the outer surface of the part should be processed some way, maybe with XTC-3D?
@jaatis, very nice indeed. Bowing out is a big concern. Having that many cells will pose an issue. On my website (18650.lt) there is a blog section. I have a graph of a test and compression force is measured there and how it changes with elevating temperature. Look it up, it will be good in understanding forces involved. This was major headache when i was designing my modules, even 6 cells would bow out sides. My solution was in the lid design to keep it all uniform.
Maybe some m3 threaded rod with coupler in the middle so you can take it out and it does not get in a way when placing or replacing cells?