Lithium-ion Simulation

[bkang003]

Hello guys,:wave:

I am thinking of putting ten same rated lithium cells in parallel. One of the concerns is that capacities will vary as I charge and discharge them. So, before the real experiment, I am considering using some simulation tool for this. I have already found that MATLAB simulink has a li-ion battery model and so does Synopsis SaberRD. Has anyone used them before for cell behavior simulation? Or does anyone have some other recommendations?

Thanks a lot!

 

[Battery Guy]

For lithium-ion cells, it does not matter because the state of charge is dependent upon the cell voltage, and the cell voltages will all be the same if they are in parallel. You could even put lithium-ion cells of different sizes in parallel (as long as they had the same chemistry, i.e. don't mix and match LFP with LCO cells) and they will all charge and discharge uniformly. As long as you are prudent with your charge and discharge rates, and the connections to the cells are good, you have nothing to worry about.

Note that this is not true for NiMH and NiCd cells, which should never be charged in parallel. But that is a different story.

Why, might I ask, do you want to put 10 18650 cells in parallel? That is a strange configuration for a flashlight.

Cheers,
BG

 

[bkang003]

I appreciated your reply, BG.

The idea is actually from my current research topic. It is for an energy storage system, 8S10P. This is just a small part of it. Since people can put cells in parallel, even if they have different capacities(assuming the same chemistry), is there a common model that is able to show or prove the way of doing this is correct?

Thanks.