If I have a 10 A load with 10 V. If I connect 5 identical cells of 10 V each with 1 ohm internal resistance in parallel, then, their Thevenin equivalent will be 10 V in series with 0.2 ohm internal resistance.
The I^2*R losses is
- 5 cells * 2^2 A * 1 ohm = 20 W
Whereas, if I use one cell of 10 V with 1 ohm internal resistance, then,
- 10^2 A * 1 ohm = 100 W
A huge difference!
But if I connect five identical cells in series where each cell is 2 V and each with an internal impedance of 1 ohm, the heat losses would be:
5 cells * 2^2 A * 1 ohm = 20 W
But it's Thevenin equivalent would be
10 V with 5 ohm resistance
The heat losses would be
10^2 * 5 ohm = 500 W
If the above is correct, does this mean parallel connection is preferred because it gives more reliability due to redundancy and it has less heat stress on the cells?