Tesla's batteries are quite ordinary lithium-ion batteries of the NMC / C chemical system with electrolyte based on cyclic carbonate esters (with lithium hexafluorophosphate). The system also contains large amounts of coolant (Ethylene glycol) and refrigerant (Tetrafluoroethane). These definitely should not be opened, etc. (no lick and eat!). And after the end of its service - it should be properly disposed. These are not more harmful than common batteries, for example for a laptop, but also not safer.