Battery Module Thermistor Layout for Thermal Runaway Detection

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Solution Overview

Problem

Existing thermal runaway detection systems in electric vehicles are prone to false positives and are expensive, and may not reliably detect thermal runaway events in batteries with multiple sealed areas.

Innovation Solution

The implementation of thermistors attached to each battery module in an electric vehicle to measure air temperature changes, using negative and positive thermal coefficient thermistors, and a controller to determine temperature change rates, generating a signal when exceeding a threshold, with a polymer material securing the thermistors and snap-fit assembly for attachment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If pressure sensors and gas sensors are used to detect thermal runaway events, then thermal runaway detection capability is improved, but false positive rate increases and cost increases

Engineering Contradiction:

Improvethermal runaway detection capabilityVSAvoidfalse positive rate

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The system divides the battery monitoring into multiple independent temperature measurement points (multiple thermistors per battery module), each monitoring specific sealed areas. This segmentation allows the system to detect localized thermal events without triggering false alarms from ambient temperature variations, thereby improving detection reliability while reducing false positives.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces thermistors as intermediary temperature sensing elements that indirectly monitor thermal runaway conditions through air temperature changes in sealed areas, rather than directly sensing pressure or gas composition. This intermediary approach provides more stable and reliable detection with fewer false positives.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If pressure sensors and gas sensors are used to detect thermal runaway events, then thermal runaway detection capability is improved, but system cost increases

Engineering Contradiction:

Improvethermal runaway detection capabilityVSAvoidsystem cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The system replaces expensive pressure sensors and gas sensors with inexpensive thermistors that can be mass-produced at low cost. Multiple thermistors can be deployed per battery module without significantly increasing system cost, achieving reliable thermal runaway detection while maintaining cost-effectiveness.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The system changes the detection parameter from pressure/gas composition (requiring expensive specialized sensors) to temperature (measurable with inexpensive thermistors). This parameter substitution maintains detection capability while dramatically reducing system cost.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If multiple thermistors are attached to each battery module to improve detection reliability, then false positives are reduced, but device complexity increases

Engineering Contradiction:

Improvedetection reliabilityVSAvoidnumber of thermistors per battery module

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The system segments temperature monitoring into multiple discrete thermistor locations within each battery module, each monitoring specific sealed areas. This segmentation strategy improves detection reliability by capturing localized thermal events while keeping each individual sensor simple and the overall system manageable through modular architecture.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The thermistors serve multiple functions: they monitor temperature in sealed areas, detect thermal runaway events, and provide data for determining rates of temperature change. This multi-functionality reduces the need for separate sensing systems, thereby managing device complexity while maintaining high detection reliability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

Provides reliable and rapid detection of thermal runaway events, reducing false positives by using multiple thermistors and a controller to analyze temperature changes, ensuring quick occupant warnings.

Implementation Method 1

one or more thermistors attached to each battery module, each thermistor configured to measure a temperature of the air around the battery module to which the thermistor is attached

Methodology Applied

Scientific EffectThermal coefficient effect: Thermistor

Data Source

PatentUS20250349920A1Thermistor based thermal runaway detection system for electric vehicle

Publication Date: 2025.11.13 ATIEVA INC(US)

AI summary

An electric vehicle includes an electric motor configured for powering the electric vehicle; a battery system configured for supplying power to the electric motor, where the battery system includes a plurality of battery modules; one or more thermistors attached to each battery module, each thermistor configured to measure a temperature of the air around the battery module to which the thermistor is attached; and a controller configured to determine, based on temperatures measured by the one or more thermistors at different times, a rate of change of a temperature of the air around the battery module and configured to generate, in response to a determined rate of change that exceeds a threshold rate of change, a signal.