This project presents the design and implementation of an Automotive Battery Management System (BMS) for Electric Vehicle (EV) applications using Embedded C. The system performs real-time monitoring, protection, and diagnostics of lithium-ion battery packs to ensure battery safety, reliability, and performance.
The Battery Management System continuously monitors battery parameters such as voltage and temperature, estimates the State of Charge (SOC), performs passive cell balancing, detects fault conditions, and simulates CAN communication for automotive applications.
- To monitor individual battery cell voltages in real time
- To monitor battery temperature for thermal protection
- To implement over-voltage and under-voltage protection
- To estimate battery State of Charge (SOC)
- To perform passive cell balancing
- To simulate automotive CAN communication
- To improve battery safety and operational efficiency
- Real-time battery voltage monitoring
- Temperature monitoring and thermal protection
- Over-voltage protection
- Under-voltage protection
- Over-temperature protection
- Passive cell balancing
- SOC estimation
- CAN communication simulation
- Fault detection and diagnostics
- Modular embedded software architecture
+----------------------+
| Battery Pack |
+----------------------+
|
v
+----------------------+
| Voltage Sensors |
+----------------------+
|
v
+----------------------+
| ADC Interface |
+----------------------+
|
v
+----------------------+
| Microcontroller |
| Embedded C Logic |
+----------------------+
| | |
| | |
v v v
SOC Fault Cell
Estimation Detect Balancing
|
v
+----------------------+
| CAN Communication |
+----------------------+
The Battery Management System continuously measures the voltage of each lithium-ion cell using ADC channels. The measured values are compared against predefined safe operating limits.
| Condition | Action |
|---|---|
| Voltage > 4.2V | Over-voltage fault generated |
| Voltage < 3.0V | Under-voltage fault generated |
Voltage monitoring helps prevent battery damage caused by overcharging or deep discharge.
Battery temperature is continuously monitored to ensure safe operation. Thermal protection is essential because excessive temperature can reduce battery life and create safety hazards.
| Temperature Range | Status |
|---|---|
| Below 45°C | Safe |
| 45°C – 60°C | Warning |
| Above 60°C | Critical |
If the temperature exceeds the maximum limit, the BMS generates an over-temperature fault condition.
In lithium-ion battery packs, cells may charge and discharge unevenly over time. Cell balancing equalizes cell voltages to improve battery life and performance.
This project uses passive cell balancing, where higher-voltage cells are discharged through balancing resistors until all cells reach similar voltage levels.
Balancing activates when the voltage difference between cells exceeds the balancing threshold.
State of Charge (SOC) represents the remaining battery capacity in percentage form.
The BMS estimates SOC using average battery voltage measurements. SOC estimation helps determine the available battery energy and improves battery utilization.
The system detects various abnormal battery conditions including:
- Over-voltage
- Under-voltage
- Over-temperature
- Voltage imbalance
When faults are detected, warning messages are generated for protection and diagnostics.
The Battery Management System simulates CAN communication used in automotive networks. The BMS transmits important battery information such as:
- Battery voltage
- Current
- Temperature
- Fault status
- SOC information
CAN communication enables interaction between the battery system and other vehicle control units.
| Technology | Purpose |
|---|---|
| Embedded C | Software development |
| GCC Compiler | Code compilation |
| Visual Studio Code | Development environment |
| ADC Simulation | Sensor data acquisition |
| CAN Protocol | Automotive communication |
- Visual Studio Code
- GCC Compiler / MinGW
- C/C++ Extension
- Code Runner Extension
Automotive_BMS/
│
├── main.c
├── bms.c
├── bms.h
├── adc.c
├── adc.h
├── can.c
├── can.h
├── Makefile
└── README.md
gcc main.c bms.c adc.c can.c -o bms.exebms.exe./bms========== BMS START ==========
Cell 1 Voltage = 4.10 V
Cell 2 Voltage = 4.18 V
Cell 3 Voltage = 4.05 V
Cell 4 Voltage = 4.20 V
Temperature = 35.50 C
Balancing Activated
Discharging Cell 4
Battery SOC = 95.21 %
========== CAN DATA ==========
Voltage : 16.53 V
Current : 12.50 A
Temperature : 35.50 C
Fault : 0
==============================
========== BMS END ==========
- STM32 / TI Microcontroller
- Lithium-Ion Battery Cells
- Voltage Divider Circuit
- Temperature Sensor
- CAN Transceiver
- MOSFET Balancing Circuit
- Current Sensor
- Electric Vehicles (EV)
- Hybrid Electric Vehicles (HEV)
- Battery Energy Storage Systems
- Solar Battery Systems
- UPS Systems
- Industrial Battery Monitoring
- Real CAN bus hardware integration
- Current sensing implementation
- Coulomb counting SOC estimation
- State of Health (SOH) estimation
- FreeRTOS support
- LCD/OLED display integration
- Wireless BMS implementation
- Cloud and IoT battery monitoring
- AI-based battery analytics
This project demonstrates practical understanding of:
- Embedded C programming
- Automotive embedded systems
- Battery Management Systems (BMS)
- ADC interfacing
- CAN communication
- Fault detection algorithms
- Battery safety mechanisms
- Embedded software architecture
The Automotive Battery Management System project successfully demonstrates the implementation of essential battery monitoring and protection functionalities required in modern Electric Vehicles. The system improves battery safety, enhances operational reliability, and provides a strong foundation for advanced automotive battery management applications.
Ashish Yadav NIT Jamshedpur Project – Automotive Embedded Systems