Project
| # | Title | Team Members | TA | Documents | Sponsor |
|---|---|---|---|---|---|
| 29 | EV Battery Thermal Fault Early Detection & Safety Module |
RJ Schneider Skyler Yoon Troy Edwards |
Wenjing Song | ||
| # Team Members - RJ Schneider (rs49) - Skyler Yoon (yy30) - Troy Edwards (troyre2) # Problem Lithium-ion batteries used in electric vehicles can experience abnormal heating due to internal faults, charging stress, or cooling failure. These thermal issues often begin with localized hot spots or an unusually fast increase in temperature before visible failure occurs. While vehicle battery management systems handle internal protection, there is a need for an external, lowvoltage monitoring and diagnostic module that can provide early warning and a hardware-level safety output for laboratory testing, validation, and educational demonstration environments. # Solution We propose a battery thermal fault monitoring module that detects early thermal fault indicators using multiple temperature sensors and simple decision logic. The system will use two independent detection paths: a microcontroller-based path for data logging and trend analysis, and a hardware comparator path for fast threshold-based fault detection. A custom PCB will integrate sensor interfaces, signal conditioning, control logic, and alert outputs. The system will be demonstrated using a low-voltage heating element to safely simulate abnormal battery heating behavior. # Solution Components ## Subsystem 1 (Thermal Sensing Front-End) Components: - 10k NTC Thermistors (x3) - 1% Precision Resistors (voltage divider networks) - MCP6002 Rail-to-Rail Op-Amp (or equivalent) Function: This subsystem converts temperature changes into analog voltage signals using thermistor voltage dividers. A simple active low-pass filter is implemented on the PCB to reduce noise from the heating element and power supply. Multiple sensors allow detection of uneven heating across the simulated battery surface. ## Subsystem 2 (Dual-Logic Decision Unit) Components: - ESP32-WROOM-32 Microcontroller - LM311 Voltage Comparator Function: The ESP32 samples temperature data using its ADC and calculates temperature rate-of-rise to generate early warning alerts. In parallel, the LM311 comparator directly monitors one sensor voltage and triggers a fault output when a fixed temperature threshold is exceeded. This provides a simple hardware backup path that does not rely on firmware execution. ## Subsystem 3 (Power Regulation and Safety Output) Components: - 5V to 3.3V LDO Regulator (e.g., AMS1117-3.3) - SPDT 5V Relay Module - Logic-Level MOSFET (IRLZ44N or equivalent) Function: This subsystem regulates input power for the PCB and provides output signaling. The relay represents a low-voltage safety cutoff output that simulates a charger-disable or contactor-enable signal. The MOSFET is used to control the heating element during demonstration and testing. # Criterion For Success 1. Hardware Fault Trigger: The comparator-based protection path must activate the relay output within 200 ms of exceeding a preset temperature threshold. 2. Early Warning Detection: The ESP32 must trigger a warning alert when the measured temperature rise exceeds a configured rate-of-rise threshold for at least 3 seconds. 3. Temperature Accuracy: PCB sensor readings must be within ±1.5°C of a calibrated reference thermometer. 4. Noise Reduction Performance: The PCB filtering stage must demonstrate reduced ADC signal noise compared to an unfiltered measurement when the heating element is active. 5. Fail-Safe Behavior: The relay output must default to an open (safe) state when system power is removed. |
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