Register to reply 
LiIon Battery Efficiency 
Share this thread: 
#1
Mar114, 06:37 AM

P: 9

Hi,
I am trying to figure out how LiIon batteries operate in regards to efficiency. I understand they have rated voltage and current etc. and to operate them at these parameters if possible. However, i'm wondering is it simply the current that has effect on their efficiency. By Efficiency I mean the amount of energy leaving the battery that get transferred to the appliance divided by the amount of energy leaving the battery. Is the energy dissipated in the battery solely due to heat dissipation? If it's operated below rated voltage what effect does this have? I also understand that LiIon operate better at higher temperatures, but does this not just mean that they operate at a higher voltage at these temperatures but aren't actually more "efficient"? Thanks for any help, trying to get my head around this! 


#2
Mar114, 07:21 AM

Mentor
P: 11,888




#3
Mar114, 07:36 AM

P: 9

Is there anyway of quantifying battery losses beyond P=[itex]I^{2}[/itex]*R? Thanks! 


#4
Mar114, 07:47 AM

Mentor
P: 11,888

LiIon Battery Efficiency
You can approximate the battery as a perfect power supply with an additional resistor in series. A larger current will lead to a larger voltage drop at this (virtual) resistor, so the output voltage goes down.
Battery loss is then given by I^{2}R = I(UU_{0}) with the zero load voltage U_{0}. 


Register to reply 
Related Discussions  
Mylar to increase efficiency of solar battery charger?  General Engineering  1  
Comparing Carnot efficiency to Stirling efficiency  Introductory Physics Homework  1  
PV Diagram Problem (ideal efficiency vs actual efficiency)  Introductory Physics Homework  2  
Battery efficiency and internal energy  Introductory Physics Homework  0  
Isentropic efficiency vs polytropic efficiency of a gas turbine  Aerospace Engineering  6 