I have a Lithium Ion Polymer battery (EEMB LP963450) and I am trying to determine how many cells are in it, and something is not making sense with my math.
Here's the formula I am using:
Determine the number of cells in a Lithium Battery:
- Battery Voltage Rating / Nominal Voltage Rating = # of cells in series
- Battery Capacity / Nominal Capacity = # of cells in parallel
- number of cells in series X # of cells in parallel = # of cells total
Here are the battery specs (at least what I have found):
- Battery Voltage Rating = 3.7 V (uncertain)
- Nominal Voltage Rating = 3.7 V
- Battery Capacity = 1800 mAh (uncertain)
- Nominal Capacity = 1800 mAh
Based on the numbers above, here's my math:
- 3.7 / 3.7 = 1
- 1800 / 1800 = 1
- 1 X 1 = 1 cell
About this point, you may be bored and asking, "yeah, so, what's the problem?" (if you think I have this correct)
So here's the problem.
With only one cell, this single-cell battery has 6.67WH ((mAh)*(V)/1000 = (Wh)) which is considerably over the 2.7WH per Lithium Ion cell for unlimited travel allowed on airplanes.
But this is a small battery so I am thinking I have something incorrect.
Maybe the Battery Voltage Rating and Capacity are not correct?
Maybe I'm plugging the numbers in wrong or not converting something I should be?
So my question is,
How do you determine how many cells are in a Lithium battery?
I've found this FedEx document too but all they do is mention you have '6 cells' and don't say how they got that number.
Dear Phil, Thanks for your inquiry. This is Donna from EEMB, glad to work with you.
For the model LP963450( 3.7V/1800mAh), it is a single cell, and your following understanding is correct.
For the battery pack, it is consisting of the cells connected in series or in parallel. If the battery stacked in series, the voltage rating will be added multiply. If the battery satcked in parallel, the capacity will be added in multiply. The following example is for your ref.
1) model LP963450-2S ( 7.4V/ 1800mAh), 2 cells in series, the voltage was added
2)model LP963450-3P ( 3.7V/ 5400mAh), 3cells in parallel, the capacity was added
3)2LP963450-3 (7.4V/5400mAh), the battery stacked with 3 cells in parallel , and then 2 battery pack in series , totally 6 cells
Hope it is clear. Any problems, please let me know. Have a nice day.
A great article on Lithium-polymer batteries: The Basics of Lithium-Polymer Batteries