BMW i3 battery modules are high performance and widely available. The 94Ah Samsung SDI (NCM 111) cells are 2kg each, 173 x 125 (+ terminals) x 45mm. They hold 350Wh and can deliver 409A.
30 cells would give 111V, 10.5 kWh and weigh a mere 60kg. Perfect!
Unfortunately, BMW modules cannot be split 🤨. This informative video shows the amazing production process, which involves a whole lot of glue and some seriously impressive laser welding.
Oh well, back to the drawing board…