Hi,
Attached is an LTSpice file and pictures where I'm trying to simulate an
A123 LiFePo4 Battery (discharge only for now).
On the very left, there is the current controlled current source F1
mirroring the current through E1. By doing this it's charging C1 and
therefore showing the discharge status (0V full, 2.3V empty) of the
simulated Battery.
I1 is a constat current soure supplying 1A and generating the charge
dependent volltage of the Battery over R2 with the long equation on
the bottom.
The voltage controlled voltage source E1 finally generates the output
voltage of the battery.
R4 is only for simulating the empty battery by making it tristate.
I2 simulates the load.
The Equation is based on several discharge courves of LiFePo4s between
1C and 20C discharge rate. Not mentioned (for now) is the capacity loss
at high discharge rates. (Please tell me if i shall explain it more
detailled)
My final goal is a chargeable and dischargeable simulation of LiFePo4
Packs for small number of cycles (no cycle aging) and self set capacity
differences to engineer a balancer.
What do you think about my simulation? Whats improvable or which other
way could it be done.
King regards
--Daniel