Had a very interesting day at work. Michael Apicella, a doctoral researcher in electrification, met with me to discuss the pros and cons of different battery options. Michael works in the Universities Future Vehicle Labs that develop hydrogen fuel cell cars. He is also a big fan if motorbikes. Considering various attributes:

• 350kg estimated total mass (including rider)
• 0-60 in 10 sec
• Using  a rear wheel 12kW (peak power 31kW) 273 DC Brushless Motor hub motor

The following spec was derived:

This spec uses Headway LifePO4 40152S 15Ah cells:

• Nominal Capacity: 15000mAh (0.5c)
• Nominal Voltage: 3.2V
• Max Charging Voltage: 3.65V ± 0.05V
• Cut Off Discharge Voltage: 2.0V
• Charging Method: CC/CV
• Max Charge Current: 3C (45A)
• Max Discharge Current (Continuous): 5C
• Max Pulse Discharge Current (30 seconds): 10C (150A)
• Recommended Discharge Current: 1C (15A)
• Cycle Life: 2000 Cycles 1C 80% DOD
• Self Discharge Rate (monthly): 2-3%
• Energy Density: 100 Wh/Kg
• Initial Internal Impedance: <6mΩ
• Storage Temperature: One Month -20°C – 45°C   Six Months -20°C – 35°C
• Operation Temperature: Charge 0-45°C Discharge -20°C – 60°C
• Diameter (mm): 40±1
• Height (mm): 152.5±0.5
• Weight: 480g

Michael also suggested that I think about the idea of using poach cells to save space and make packaging of the power unit more efficient.