Optical Pyrometer Thermal Event Detection in Battery Modules

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Solution Overview

Problem

Existing electric vehicles face challenges with battery overheating, leading to reduced range, durability, and safety issues due to the inability to effectively detect thermal events in battery modules until after a combustion event occurs, necessitating a more efficient early detection system.

Innovation Solution

A thermal event detection system utilizing an optical pyrometer within a battery module, combined with reflective surfaces to enhance infrared radiation detection and reduce absorption, allowing for early identification of overheating cells and initiation of mitigation measures such as active cooling or power reduction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional temperature detection methods are used in battery modules, then the system structure remains simple, but thermal events cannot be detected early enough (only after combustion occurs)

Engineering Contradiction:

Improvethermal event detection timingVSAvoiddetection system structure

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces traditional mechanical/physical temperature sensors with an optical detection system. The optical pyrometer detects thermal radiation (infrared) emitted by battery cells to determine temperature, substituting direct physical contact measurement with remote optical measurement, enabling earlier thermal event detection before combustion occurs.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces reflective surfaces as intermediaries within the battery module. These surfaces reflect infrared radiation from battery cells toward the optical pyrometer, enhancing the detection signal and enabling earlier and more reliable thermal event detection without requiring the detector to be in direct line-of-sight with all cells.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Duration of action of moving object

If heavy high voltage battery systems are used to achieve long range, then the battery capacity increases, but the vehicle weight increases and acceleration performance decreases

Engineering Contradiction:

Improveelectric vehicle rangeVSAvoidvehicle weight

Core Design Contradiction:

Duration of action of moving objectVSWeight of moving object

Solution Approach 1:

The patent implements preliminary thermal event detection using optical pyrometry to identify cells approaching dangerous temperatures before thermal runaway occurs. By detecting thermal events early in the progression (before combustion), the system can initiate mitigation measures such as isolating affected cells or activating cooling systems, preventing catastrophic failures that would reduce battery capacity and range over time.

Inventive Principle:

Principle #10Preliminary action

3Power

If battery cells operate at high power output to maximize performance, then the power delivery increases, but the temperature increases and battery longevity decreases

Engineering Contradiction:

Improvebattery power outputVSAvoidbattery longevity

Core Design Contradiction:

PowerVSDuration of action of stationary object

Solution Approach 1:

The patent implements a feedback control system using optical pyrometers to continuously monitor battery cell temperatures. The detected thermal radiation signals are processed to determine cell temperatures in real-time, and this information feeds back to the battery management system, which can adjust power output or activate cooling measures to maintain optimal operating temperatures, thereby extending battery longevity while preserving performance capability.

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

Enables early detection and prevention of thermal runaway, increasing battery longevity, efficiency, and vehicle range by allowing for timely intervention before overheating propagates across the battery module.

Implementation Method 1

an optical pyrometer arranged inside the module for detecting thermal runaway of one of the cells

Methodology Applied

Scientific EffectThermal radiation: Thermal Radiation

Implementation Method 2

reflective surfaces arranged at predetermined positions within a battery module

Methodology Applied

Scientific EffectReflection: Reflection

Data Source

PatentUS7939192B2Early detection of battery cell thermal event

Publication Date: 2011.05.10 TESLA INC

AI summary

A battery module for use in an electric vehicle is disclosed. The battery module includes a plurality of cells arranged in a predetermined pattern within the module. The battery module also includes an optical pyrometer arranged inside the module. The optical pyrometer is installed within the module after being tuned to detect a predetermined frequency or band of frequencies. The pyrometer will be used to detect an increase in short wave radiation density from one of the battery cells within the module wherein that battery cell has a temperature above a predetermined threshold. The optical pyrometer will be used to communicate an electric signal to a control system of the electric vehicle wherein that control system will implement a predetermined mitigation process to contain the thermal event of that one cell within the battery module.