They are still relatively simple. A battery management system for the lithium cells. The same technology as on any lithium cell powered device where the voltage of individual cells is monitored so that they can't either run down completely to zero and charge too high. This couples via CAN bus in the case of CHAdeMO charge ports and for AC charging and via the pilot connector for CCS charging ports A three phase AC motor (normally 400V). Not too dissimilar to that in a train. Some kind of speed regulation and regenerative braking (again the same technology as a train can be used). A dirty great lithium battery pack. A three phase inverter for providing three phase AC for the motor. An AC on board charger (can be either single or three phase) with rectifier to convert to DC for the battery. A heat pump for the heater/air con Some kind of cooling for the battery, inverter and motor - normally liquid cooled with conventional antifreeze. The rest of the technology is appearing on ICE cars anyway (safety systems, infotainment, autonomous driving, suspension, friction braking, steering) What Tesla do is remarkably like Apple. They package it up really well and pump the price up. Case in point. The VW iD3 will be cheaper than the model 3 with a similar range, charging speed and arguably better build quality (VW for all their faults do know how to put a car together).