10S4P with Lithium ion battery; Question on the calculation

[marellasunny]

I am planning to use the Panasonic NCR-18650 cylindrical cells for a BEV (Battery Electrical Vehicle). As it would be easier to buy ready-made modules, I have found a supplier selling a Li-ion pack that delivers 417 Wh(or in other words 11.6 Ah) at 36 V (something like what this guy uses... http://www.electricbicycleworld.com/36V-11-6Ah-Lithium-Ion-Frame-Bottle-Mount-p/hx-bb-11.6ah-36v.htm ). Upon further inquiry, he says its a 10S4P i.e 10 in series and 4 "strings"(whatever that means) in parellel.

The Voltage and Energy density calculation part is where I get confused:

The panasonic datasheet says that each individual cell has 10.44 Wh of energy and supplies it at 3.6 V.
So,

10 cells in Series → 36 V and 10.44 Wh

IF I arrange these cells in 4 "parallel" rows, I get → 36 V and 41.76 Wh. But, the guy claims 10S4P supplies 417Wh. Where am I going wrong?

 

[montoyas7940]

10 cells in Series → 36 V and 10.44 Wh

Where am I going wrong?

You are keeping the same watt/hr value despite the increase in number of cells.

P=IE

 

[montoyas7940]

BTW I have an old tadpole recumbent trike I have thought about motorizing as well. I would enjoy watching your progress as you build.

 

[marellasunny]

BTW I have an old tadpole recumbent trike I have thought about motorizing as well. I would enjoy watching your progress as you build.

My build will be from time-to-time be posted in the Automotive engineering forums in Physics forums. I would love to document and share the information online but unfortunately my contract blocks me from doing so. Neverthess...you'll find me in the AE forum :).

Last question:

What is the difference between connecting the cells in a 10S4P format('TEN' 18650 cells in Series arranged in 4 columns connected in parallel) as compared to connecting the cells in a 40P (all 40 cells in parallel) ?

10S4P-pack gives me 36 V and 417 Wh and 11.6 Ah.

40P-pack on the other hand gives me 3.6 V and 417 Wh and 116 Ah. ( like this pack here...http://www.kreiselelectric.com/en/technology/battery-system/battery-pack/ )

My Brusa HSM1-10.18.13 motor has a specfication of 360 V - 400 V and max RMS current of 300A.

 

[montoyas7940]

Last question:

What is the difference between connecting the cells in a 10S4P format('TEN' 18650 cells in Series arranged in 4 columns connected in parallel) as compared to connecting the cells in a 40P (all 40 cells in parallel) ?

10S4P-pack gives me 36 V and 417 Wh and 11.6 Ah.

40P-pack on the other hand gives me 3.6 V and 417 Wh and 116 Ah. ( like this pack here...http://www.kreiselelectric.com/en/technology/battery-system/battery-pack/ )

My Brusa HSM1-10.18.13 motor has a specfication of 360 V - 400 V and max RMS current of 300A.

I'm not sure what you are asking regarding the difference. But the voltage and current you are considering can be very dangerous. You need an expert.