Link: FAQ: The mounting position of the LFP cells

“Batteries must be kept upright. They are very dependent on orientation.” 

This statement is not correct,  TS cells can be laid on their sides, I have confirmed this with ThunderSky several times  and I have used them on their sides in several of the EV conversions I have done with no ill effects. 

ThunderSky does warn though that if the cells are over charged the vent can open and if they are on their sides the electrolyte can leak damaging the cell.  If you use a good BMS you should never overcharge the cells so this shouldn’t be a problem.