DESIGN AND CONSTRUCTION OF A PROTOTYPE BATTERY MANAGEMENT SYSTEM IN REFERRENCE TO ELECTRIC VEHICLES

ABSTRACT This project focuses on the Design and Construction of a Battery Management System (BMS) in reference to an Electric vehicle (EVs). A major challenge in EVs is the instability of lithium ion batteries due to overcharging, under charging, discharging, and temperature variations. These issues can lead to reduced battery life, performance inefficiencies, or even safety hazards such as thermal runaway. The BMS addresses these problems by continuously monitoring cell voltages, currents, and temperatures. Conventional systems often use passive balancing techniques or basic monitoring circuits that lack real-time responsiveness and scalability. While these systems provide fundamental protection, they fall short in handling dynamic EV loads and complex energy management. This project aims to overcome such limitations by designing an intelligent, and real-time responsive BMS optimized for electric vehicle applications. To achieve the project objectives, a DHT11 temperature sensor was used to continuously monitor ambient conditions, and a PIC microcontroller was programmed to adjust help monitor the voltage and current readings. The system is powered by a 12v Sealed Lead acid battery (SLA) and a real time data display using an LCD. Each design aspects were developed in line with the primary objectives. The method employed in this project involved the design and implementation of a microcontroller-based BMS capable of monitoring key battery parameters—voltage, current, temperature, and state of charge in real time. The system integrated voltage sensors, current sensor, and thermistors, all interfaced with a microcontroller unit programmed to execute protection algorithms. The objective was to ensure efficient battery health monitoring, fault detection, and active cell balancing. The system was tested under various load and charge/discharge conditions to evaluate its responsiveness and reliability. Testing involved subjecting the BMS to controlled use with available loads for. Data were collected on voltage consistency, temperature variation, and the accuracy of SOC estimation. The system's balancing mechanism was also evaluated by introducing cell imbalance and observing correction over time. Observations showed that the BMS maintained cell voltage within the safe range of ±0.05V across the pack, responded effectively to temperature thresholds by shutting off, and improved SOC accuracy through algorithmic filtering. The test results confirmed that the constructed BMS performed as intended, offering stable battery operation, accurate parameter monitoring, and efficient balancing. The system demonstrated reliability under varying electrical and thermal loads typical of EV applications. In conclusion, the designed BMS proves to be an effective solution for enhancing battery safety, longevity, and performance in electric vehicles. It successfully addressed key limitations of existing methods through real-time monitoring and control. It is recommended that future work focuses on integrating wireless communication for remote diagnostics and upgrading to a more powerful processing unit to handle faster response times in high-performance EVs