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Final Packaging
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Various options exist for packaging the final cell-pack;
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simple tape (of various sorts)
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heat-shrink
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bespoke / custom made / purchased
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3D printed...
or a combination of some or all of them.
In my case it tends to depend upon various factors;
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the size and shape of the pack I'm creating
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the use the pack is being put to
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any additional components I wish to include with the pack
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the environmental protection the pack will require
I am lucky enough to have a fantastic 3D printer and to have spent many hours putting Sketchup to good use refining my design skills. I tend to favour 3D printing to create bespoke housings, brackets and other bits'n'bobs I require.
Example 1:
A 4P pack I designed and made to wirelessly charge my mobile phone.
The 4 cells are connected in parallel and each one has its own BMS.
Because the cell-'pack' resides, snugly, within a 3D printed box / enclosure, no additional protection is required.
The left-hand image shows the 4P battery holder. 4P - 4 sells in parallel.
There are THREE wires becaue the BMS units are of the split-port type; the thicker red/black are for the power o/p connections and the thinner blue cable is the charge -ve (charge +ve connects directly to the thicker red)
The right-hand images hows how the underside of the pack was designed to allow the BMS units to fit in-between the batteries and connect to a pair of common +ve / -ve 'rails'.
A 3S pack I intend to use to provide 10V - 12V for the scoot project.
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Example 2:
The pack will be tie-wrapped down and won't be able to move.
Apart form the BMS there are no additional components to mount or protect.
It should be in a relatively water-free environment.
Once assembled (with the BMS) it was wrapped in 3mm foam and heat-shrunk in both directions.
The 'end caps' I designed and made to finish the 20S4P packs I intend to put to use on the scoot project.
Example 3:
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This particular 'build' required both 3D plastics for the end caps and the CB housing and then heat-shrink to bind the finished pack together once protected by 3mm foam.
The ribs around the ends of the end-caps are to provide enough 'grip' for the heat-shrink to keep the pack together longitudinally.
This pack was designed to be modular - the idea being that it should be readily removable for charging and security and that it would function equally well as a single pack for an ICE to electric lawnmower project AND in a parallel configuration for the scoot project. In both cases, 'long and thin' seemed to fit my project design expectations... we'll see how things pan out...
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With a little more time being spent with the scoot and my decision to run with a mid-mount motor I may yet change the design due to length constraints and my hopes to keep the under-seat area free for a helmet (probably pie-in-the-sky by the time I get a charger on board as well.
This long'n'thin design does, however, suit the lawnmower project where it sits across the width of the mower just behind the motor...