Do I need diverter to charge my car using excess generated power from solar panels?

The need for a separate Solar PV diverter depends mostly on your EVSE (car charger). Some chargers already come with the capability to intelligently divert any extra power from your solar panels by monitoring your grid connection or a combination of solar panel output and your house consumption. Smart EVSE still requires the installation by a licensed electrician, but the overall system is much simpler than the alternatives.

Car chargers, which do not support monitoring your electrical grid, may still allow controlling the charging by an external system, but complicates the overall setup and requires multiple modules to work together to achieve the goal.

Car chargers, which neither can monitor the grid and doesn't support external control of the charging current, may not work well even with a Solar PV diverter depending on the mode of operation of the Solar PV diverter and the design of the car charger.