The holes for the 18650 cell holders were to small on the first PCB. So I modified the holes on the PCB and ordered version two from JLCPCB. The PCB gerber files are attached in the project resources.

After receiving the manufactured PCBs I can confirm that all measurements and holes in v0.2 are correct.

Here is a test-fit of the first three modules stacked together using the metal M3 standoffs. I've continued to populate and solder all ten PCBs. Here are some impressions:

For more safety during the assembly and testing no fuses are used in the modules. In the next step I will charge/balance all cells and connect them electrically.