if i put 2 LFP battery 12.8v 60 amp in series and the starting current for the truck reach 600 Amp what happens to the lithium battery?
More specific details about the battery is needed to determine its maximum surge capacity and continuous delivery rating. However since this battery system falls well short of 600A I do however expect a much shortened battery life, high risk of overheating and possibly fire. Best to check with a professional battery supplier if they have any experience as this is a solar forum. Typically you also still see LA used for starting generators next to a Lithium installation.
In fact, the older VICTRON pre-smart battery datasheet lists 600A 10 second discharge current for the 60ah batteries. However they also make it very clear you need to be using a BMS if you run them in series or parallel in case of cell over or under voltage, so be warned.
I’m not 100% sure the newer smart batteries have the same specs.