In this video I'm going to show you how I build my batteries using LG Chem's prismatic
pouch cells.
I bought these cells from an Alibaba merchant called Victpower.
I cannot guarantee they are authentic LG Chem cells but I can tell you they are performing
to spec.
I decided I wanted to make the battery as compact as possible by getting the cells as
close together as possible but I didn't want them touching each other so they wouldn't
transfer heat to each other for thermal runaway situations.
So I came up with this idea to use double-sided foam tape.
I think it worked out well as it adds to the mechanical stability of the entire battery.
To be safe I insulated all of the positive terminals of all the cells while I worked on it
I wanted to connect all the tabs together on a printed circuit board but JLC PCB was
way too expensive.
So instead I created a circuit design in MS paint, made my own glass fiber reinforced
panels, and sent everything to be laser cut.
If you're like most people and don't have access to a laser cutter then you can do it
the arts and crafts way.
When I did my glass layup I laminated in the artwork that I printed out on a printer.
It didn't really bond very well to the resin and glass so i don't recommend it.
My plan is to install rivet nuts and here you can see me checking the drilled holes
for size.
A rivet nut is a kind of "captured" nut and it works very well with glass fiber reinforced
panels.
I have to say I really prefer the laser cutter to the Dremel method.
(cough cough)
To install rivet nuts is pretty simple.
You just need to drill the correct hole for the correct rivet nut size and in my case
I'm using a combination of m4 and m6 rivet nut.
And then of course you're going to need a rivet nut riveting tool.
I decided that since the anode is made out of nickel plated copper and the cathode is
made out of pure aluminum that I would use stainless steel rivet nuts.
Here's a close-up of the rivet nut being installed.
You can clearly see the bits of paper that didn't properly laminate to the resin.
Since the end circuit boards need to be an insulated material, I tried various different things.
There's a high amount of force when the rivet nut compresses and acrylic cracked and Lexan
just bent. This is a testament to just how strong glass fiber reinforced panels are.
The main reason I went with rivet nuts is that I needed a captured nut. You could use regular nuts and bolts but there's a high risk of shorting the battery terminals together
while trying to hold the nut on the back side of the circuit board.
Here's the finished product with the rivet nuts installed.
Once you slide all the tabs through the slots, you take the corresponding tabs and you fold one over the other to achieve a series configuration.
I then fabricated aluminum bus bars to sandwich the tabs to each other.
She looks a bit rough but i promise you with a laser cut panel it looks a hell of a lot
more like a finished product.
with this design you can add a nice healthy lug (ring terminal) on the positive and the negative outputs
And now for the BMS wiring
I like to both crimp and solder my lugs to ensure a very low ESR (equivalent series resistance) connection.
All the rivet nuts and cap screws are made from stainless steel.
Once all the BMS wiring is done the BMS is installed for a final test.
I chose to go with a solid aircraft aluminum case to demonstrate this product.
To ensure a waterproof connection half inch cable glands were utilized.
The inside was coated with three layers of glass fiber and resin to prevent short circuiting (to the case).
Well that's the end of video hopefully you got something out of it.
I guess I'm going to have to say what all the other youtubers say "please like, share, and subscribe.
It is my hope that if I can get monetized and make enough money
that I will practically give the scooters away just so that i can make more build videos.
Thanks for watching!!