mux said:There's been a few distinct changes over time, chemically:
- Pure LMO on the initial packs (e-bike chemistry, essentially), very forgiving on charging/discharging current but very bad cycle life
- Al-doped LMO still on gen1 packs, but late in the game (2013ish?), charges to 4100mV/cell now
- Retuned BMS on gen2, no apparent change in the actual battery chemistry, charges to 4130mV/cell
- NMC on gen3 (30kWh), charging to 4180mV/cell
- Higher nickel content NMC on gen4, Li-HV tricks to get a fair bit of extra capacity by charging further (4220-4224mV/cell)
- Then a set of massive BMS retunes to try to fix rapidgate, mostly by increasing charging speeds at subcritical temperatures
- Then a density increase through slightly thinner packaging/electrodes on gen5 (62kWh) and quite a significant change in the BMS again
Altogether we see about 8 distinctly behaving battery packs through the years. I started off by saying they didn't change things every year, but looking back at this list... yeah, on average every year *something* changed in some significant way.
Mux;
Is there a standardized method of determining the useable energy available as a result of these changes? "Standard" meaning Nissan's (standardized) SOC limits applied under standard testing protocols? From FLA/AGM/SLA(VRLA) background, energy was a amp-hour/voltage calc, but not sure that Li tech is that simple!