ORIGINAL: Fred Marks
You stand corrected. What happens, worst case, on 1 or 3 cell is readily translatable to 10S since the cell is run with no cooling. In the 10S case, the cells are enclosed in heat shrink, so inner cells receive no cooling.
Not entirely true...if the outer cells are being cooled then the inner cells will have conductive transfer between them toward the outer cells receiving the cooling. Spacing out the cells would actually make things worse as the heat transfer coefficient from the cell to air would be lower than from cell to cell.
Just because they see no "airflow" does not mean they are not being cooled.....this information is any heat transfer text.
To see some effect I did the following.....
I had packs seperated by 3/8" spacing (x2 5s 5300 packs, big sides facing each other, so basically the large flat sides of the cells).....flew a lot and measured the face temperature of the pack in this gap. The cells in this gap were only typically 1C higher than the cells fully exposed to the airflow (giving me confidence that boundry layer formation in the gap was not seriously affecting the airflow for cooling in this space).
Joined the packs together and flew a lot of flights again, after the flights opening the packs and measuring the face temperture. A whopping (get ready!) 3-5C increase over the exposed outer cell temperatures. So for a net change of 1-4C increase.