I am in charge of designing a 485 Vdc pack for use by my company. The application is not directly EV, but is for powering equipment in the back of a truck (it will replace a PTO driven system which is very wasteful). We have already tested a 40 Ah TS cell for use at our load currents (20,30,40 Amps). Now I need to see if we can do the same with 160 in series.
The duty cycle for this system is very low, would only be used in 30 - 90 second spurts at up to 40 amps with half an hour or more in between.
I want to ask you all what you think about this size pack, and whether it will be sustainable. ie: will we be pulling dead cells out of it left and right.
Before we go any further I want to say that I plan to use the on-board computer to sample the voltage across every cell, and the temp of the pack at many locations at a rate of 0.5Hz. Obviously current draw and over voltage / under voltage protection will be used. We also will be designing a simple analog pack balance checker for when the computer is not on.
One of the first questions that I am considering is how in the heck we're going to charge this thing. I am hoping for a little insight in this regard. Does disconnecting into strings of 16 and charging them individually sound like a reasonable idea?
Please let me know what concerns you would have with a pack this size, and how you would go about charging it.
btw- we're actually looking into CALB cells now, rather than TS.