Question on Tesla Battery Cell Charging Currents

[Skiddins]

I have read up a little on the battery packs, 6 groups of 74 cells in each moddule, and 16 modules in series etc, but does anyone know what current is being put into each 18650 battery cell when the car is plugged into a Supercharger station?

I'm just interested in how hard each lithium cell is being pushed with regard to the Amperage being put in.

Thanks

 

[scaesare]

Current is the same for all components in a series circuit, so each group of 74 parallel connected cells is seeing the whatever current the supercharger is outputting, which has a max of around 330A,

Each of the 74 cells draws 1/74 (minor cell variation not included) of that current, so round numbers at max power is about 4.5A per cell.

 

[Skiddins]

Interesting, I thought the current would be a lot higher than that.

 

[scaesare]

The cells are assumed to be in the 3.3-3.4Ah range. So the fact that they are seeing a charge current of ~1.5C makes sense when you consider the superchargers are rated at ~1.5x the power of the pack (for an 85KWh pack and a 120-135KW supercharger), once you consider losses...

 

[Skiddins]

It's interesting as in my hobby we use the LiPo 'pouch' type cells in 2s configuration (7.4V) and recently people have been charging at high current rates to gain performance (the warmer the cell the lower it's internal resistance, so the greater the current it can supply), of course this is negated in a Tesla by the use of far higher voltage.
People have been charging our 2s lipo packs at 40-50Amps

 

[Johan]

Different chemistry all together - like comparing apples to oranges. Also, the Tesla car is working hard to keep temperature down during supercharging, to avoid degradation.