ON 3/8/21 I WAS DRIVING MY 2017 TOYOTA HIGHLAND APPROX. 13 MILES AWAY FROM MY HOME. I BEGAN TO SMELL SMOKE AS I WAS DRIVING AND THROUGH FURTHER INVESTIGATION I FOUND THE SMOKE TO BE COMING FROM THE CHARGING PORT AT THE BOTTOM OF THE MIDDLE ARM REST. THERE IS A FUNCTIONAL CAP ON THIS PORT TO KEEP DEBRIS FROM FALLING INTO IT. I DID NOT SEE ANY DEBRIS IN IT AT THE TIME OF THE INCIDENT. BUT WHILE CHECKING FOR THE SOURCE OF SMOKE I FELT HEAT COMING FROM THE PORT AND THEN IT MELTED TO THE FLOOR. ONCE THIS HAPPENED I PULLED OVER TURNED THE TRUCK OFF AND EXITED.