I required a large battery module for my Ultimate Commuter E-bike Project. The process was to purchase the cells, design cell trays, battery case, cooling circuit, and wire everything up. I went with a similar design of battery shell to the Rad Rocket E-Bike. I found pre-constructed battery modules on Facebook marketplace for a good price containing LG 2170 Cells and I needed to construct a 60V nominal system that also had high capacity and a good continuous discharge rate. I will break down the Module Design into three components, the battery pack, the shell, and the accessories.

Battery

I knew I was going to build an electric motorcycle so I was shopping around on Facebook marketplace for lithium ion cells. I ended up finding this guy selling a 2170 Solar module that contained LG INR2170 M50LT Cells. I found the data sheet and found each cell had a capacity of 5ah. These were some energy dense cells but their discharge rates weren't as high as I would like them to be (Max discharge rate was 14Amps per cells). I still went ahead with this because I was getting 110 cells for $120 and these cells were manufactured in 2021. I could have almost been able to do 16s-7p but that would require 112 cells and I only had 110 on hand. I had to disassemble the Solar Module and reconstruct to my voltage specifications.

I purchased a 50A continuous BMS, the max continuous limit for my pack is 84A but I wanted to keep things on the safer side. I designed battery trays with holes for the main power output lines as well as balance leads, a section for the BMS, bolt pattern for a desktop fan, and Bus bar strip grooves. I separated the Cell trays into 2 parts for each side connected to each other with dovetail mounts then inserted the cells in my trays. In my CAD model I created an assembly for the battery pack alone before it would be inserted in to the assembly with the case along with everything else.

After inserting all 96 cells, It was time to spot weld everything together as well as hook up the BMS to the module. I had a bracket for the BMS to rest on, then it was time to route all of the balance leads through the channels I built into the battery trays. Post instillation of the BMS, I quickly designed a temperature controlled fan circuit with a N channel MOSFET, Potentiometer, and 10K NTC thermistor. I also ended up installing a voltage indicator to let me know what voltage my battery pack is at. After everything was installed, It was time to slip on the clear heat shrink over the module and shrink it all down with some HEAT. Below are images of the completed battery module.

Shell

Now that the module was completed, It was time to design and construct the battery case. I started off by  creating an assembly for the whole bike where I inserted parts and sub assemblies like the battery pack, controller case, bike master-part, controller, and the module shell. My main objective was to have the Battery Module fit clean and secured within the frame area. I made it so that there was 0.125in gap on either side to account for any high spots from welds on either side. 

I utilized a similar structure to my RAD ROCKET E-bike where the skeleton would be 3D Printed and the empty sidewalls would be an aluminum plate that is riveted into the shell. I designed an output port for the large XT-90 connector as well as a hole for the barrel jack port and a slot on the top cover for the voltage display line. I also designed a controller mounting system where I could clamp the controller to the battery module so that all the components are close together to reduce the length of large wires and any excess resistance. After all of this I was left with the design below.

It was time to 3D print, I created a new profile specifically for this battery case. I did 12% infill and an Adaptive Cubic infill pattern. The low infill percentage was due to the thickness of the shell already being 0.125in thick so having a high infill pattern wouldn't add much value compared to the increased material quantity.

After everything was printed I had to cut out the aluminum panels, two that were 6.125in x 17.75in, and the other two that were 3.25in x 17.75in. These panels allowed for an increase in structural rigidity as well as keeping print times and filament material down. I aligned the two shells together, inserted the panels on all 4 sides, then riveted them all down. 

Now that the shell was complete, I simply slid the battery pack into the shell, routed the power leads through, Plugged in the 2.5mm Barrel Jack charging port, and my battery module was completed.

ALL FINAL IMAGES ARE ATTACHED BELOW