The difference between a 7kW and 22kW EV charger is the rate at which they charge the battery. A 7kW charger will charge the battery at 7 kilowatts per hour, whilst a 22kW charger will charge the battery at 22 kilowatts per hour. The faster charge time of the 22kW charger is due to the higher power output.
If you are charging your vehicle with a 22kW charger, it will take approximately 3-4 hours to charge an electric car with a 22kW EV Charger. This time will vary depending on the size of the battery and the current state of charge.