Battery Module Relay Isolation for Thermal Runaway Detection

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Solution Overview

Problem

Conventional thermal runaway detection and mitigation systems for high voltage battery systems in electrified vehicles are not robust and costly, with physical fuses or busbar connections requiring replacement and manual service disconnects being expensive solutions.

Innovation Solution

A battery management system (BMS) with a relay connected between battery modules and control logic that detects voltage changes to prevent thermal propagation, including diagnostics to ensure relay functionality and operation during sleep mode and maintenance, without the need for a manual service disconnect.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a physical fuse or busbar connection is implemented between battery modules, then thermal propagation is mitigated, but the system requires replacement after malfunction and becomes less robust

Engineering Contradiction:

Improverobustness of thermal mitigation systemVSAvoidreplacement requirement after malfunction

Core Design Contradiction:

ReliabilityVSEase of repair

Solution Approach 1:

The patent replaces the mechanical physical fuse or busbar connection with an electronically controlled relay system. The relay is controlled by a microcontroller that monitors battery module temperatures and activates the relay to disconnect modules when thermal runaway is detected. This electronic control system eliminates the need for physical replacement components, improving robustness and ease of repair.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If conventional battery management techniques are used, then the system works for its intended purpose, but it lacks robustness and requires costly manual service disconnects

Engineering Contradiction:

Improverobustness of battery management systemVSAvoidcost and complexity of manual service disconnect

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a self-service battery management system where the microcontroller continuously monitors battery module temperatures and automatically activates the relay to disconnect modules when thermal runaway is detected. This eliminates the need for costly manual service disconnects while maintaining robust protection, as the system serves itself by autonomously detecting and responding to thermal events.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent employs a feedback mechanism where temperature sensors continuously monitor battery module temperatures and provide data to the microcontroller. The microcontroller processes this feedback and automatically activates the relay when thermal runaway conditions are detected. This closed-loop feedback system improves reliability by providing continuous monitoring and automatic response without requiring complex manual intervention systems.

Inventive Principle:

Principle #23Feedback

3Speed

If voltage change detection is used to detect thermal runaway, then detection speed is improved, but the system requires sophisticated control logic

Engineering Contradiction:

Improvedetection speed of thermal runawayVSAvoidcomplexity of control logic

Core Design Contradiction:

SpeedVSDevice complexity

Solution Approach 1:

The patent uses voltage change detection as a feedback mechanism to rapidly detect thermal runaway events. The microcontroller monitors voltage changes between battery modules and automatically activates the relay when abnormal voltage changes indicate thermal runaway. This feedback-based approach achieves fast detection while keeping the control logic relatively simple through automated threshold-based decision making.

Inventive Principle:

Principle #23Feedback

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The BMS effectively detects and mitigates thermal runaway events, providing robust and cost-effective protection for high voltage battery systems by quickly disconnecting modules and generating alarms, while avoiding the need for expensive manual service disconnects.

Implementation Method 1

detect the thermal runaway event of the high voltage battery system based on a change in the voltage over a period

Methodology Applied

Scientific EffectVoltage change detection: Electric Field

Implementation Method 2

open/close the relay in response to detecting the imminent thermal runaway event

Methodology Applied

Scientific EffectRelay switching: Relay

Data Source

PatentUS20240424903A1Thermal runway detection and mitigation systems and methods for battery systems of electrified vehicles

Publication Date: 2024.12.26 FCA US LLC

AI summary

Thermal runaway detection and mitigation techniques for high voltage battery systems of electrified vehicles include a relay connected between two battery modules of the high voltage battery system and control logic for the relay, the control logic being configured to determine a voltage between the two battery modules, detect the thermal runaway event of the high voltage battery system based on a change in the voltage over a period, and open/close the relay in response to detecting the imminent thermal runaway event, wherein the detection of the thermal runaway event and the responsive opening of the relay prevent or mitigate potential thermal propagation outside of the high voltage battery system.