Cool sounding project if you make a post about it please PM me, or link it here.
I was researching the excellent suggestion about laptop batteries having short life because of their high utilization strategy in mobile electronics, and battery university website backs this up. (https://batteryuniversity.com/learn/art ... _batteries
) It in fact show how much longer one could expect in various charging scenarios. right out of the gate, they say for every .1v that the cell is not charged under 4.2v it doubles the life, and not storing at high charge levels increase life a further 20%, those are freebies with no behavior change. going further, shallow cycling really increases life proportionally to depth of discharge, so where a 100-25 charging pattern might expect X cycles full life, 85-25 would have 2x cycles, and 75-45 would have 5x cycles. expanding capacity to 44kwh will allow very shallow discharges on a daily basis while allowing for 100%-25% 150+mile long trips occasionally. the temperature aspect of it also supports some kind of TMS as heat reduces life.
The only technical issues i can anticipate is that the 80kw acceleration will draw ~220amps from the pack, with 48 parallel cells each one will need to have a peak draw rate of 4.6 amps for at least a few seconds, that might be above what a laptop cell can provide, not that high drain and high capacity 18650 cells don't exist, but they are not $1/each.
Thinking on assembly, i think that using nickel strap material will be needed to connect the cells to the modules internal buss bar, 1mm thick copper might not spot weld easily to the cells, and will prevent any kind of service, whereas if we get 12.7x.25mm nickel strapping and make connections to the bus bar that way i can spot weld everything much more easily and then fold the bars flat to the pack afterwards, the only thing left after that is creating the copper to copper buss bar connections. I want the design to be manufacturerable in anyones basement or garage. maybe the cross bars could be nut and bolted in to maintain serviceability, also i would make the connections on the top of the pack now, to maintain access for cooling hardware on the back of the cells.
it would be great if someone could help test the modules in a car, while i am working to someday make a pack for my car, I commute a long way each day and my 2012 cannot be down. I might consider buying a 2011 leaf with a nearly dead pack, or crash damage etc as my test mule.