Hybrid Electric Vehicles (HEVs) functions using a combination of electric power and fossil fuels like petrol or diesel. HEVs are operated with their dual power sources, which presents unique challenges and opportunities in terms of thermal management. Lithium-ion batteries on the other hand, are sensitive to operating temperature and performs best within a certain temperature range. Consequently, to guarantee the safe operation of HEVs, a Battery Thermal Management System (BTMS) is required. This paper presents an IoT-based thermal monitoring system for hybrid vehicle where the sensor data is uploaded to cloud and controlled by developing the code on Arduino IDE-Embedded C environment. This work uses DS18B20 and DHT11 temperature sensors and MQ-135 gas sensor which records the physical parameters and uploads it to the cloud. The NODE-MCU ESP8266 is the core component of this work, which reads sensor data and receives control signals from the Blynk IoT app for motor control. The ESP8266 then transmits this data back to the app for visualization. The developed code is dumped into the Arduino IDE environment which compares the sensor measured value with the threshold temperature and gas value stored already in the cloud for decision making. Proportional Integral Derivative (PID) controllers and fractional PID controllers are used for speed control of HEV-DC motors. The L298N, a dual H-bridge motor driver Integrated Circuit (IC) allows the module to control the speed of motors, which directly controls the speed of the vehicle. In addition to this, use of monitoring circuit in BTMS will monitor the key parameters of the battery like voltage, current, temperature during charging and discharging situation. The developed moule is found to be improved in the areas of flexibility, scalability, complexity and performance.