Fiber Bragg Grating Gas Detection for Early Battery Thermal Runaway
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Solution Overview
Problem
Current thermal runaway detection systems in batteries often fail to detect the onset of thermal runaway in its early stages, leading to irreversible conditions and hazardous events due to reliance on temperature and pressure sensors, which provide alerts too late and can result in false alarms or missed detection.
Innovation Solution
A system utilizing a light source emitting a spectrum of wavelengths and optical fibers with filtering mechanisms, such as fiber Bragg gratings, to detect gases like ethylene carbonate, diethyl carbonate, and dimethyl carbonate released during battery decay, enabling early detection of thermal runaway through spectral signature analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If temperature and pressure sensors are used for thermal runaway detection, then the system structure is simple, but the detection timing is too late and reliability is poor
Solution Approach 1:
The patent replaces traditional mechanical/physical sensors (temperature and pressure sensors) with an optical detection system using fiber Bragg gratings and light sources. This substitution enables detection of gas composition changes through spectral analysis, providing earlier and more reliable detection of thermal runaway onset by identifying characteristic gases before temperature and pressure changes become significant.
Solution Approach 2:
The patent introduces fiber Bragg gratings as intermediary elements that interact with characteristic gases released during battery decay. These gratings modulate light based on gas presence, enabling indirect detection of thermal runaway conditions through optical signal changes rather than direct temperature or pressure measurement.
2Measurement precision
If temperature and pressure sensors are used, then device complexity is low, but detection precision is insufficient for early stage thermal runaway
Solution Approach 1:
The patent replaces imprecise temperature and pressure sensing with optical spectroscopy-based detection. By analyzing the spectral signatures of gases interacting with fiber Bragg gratings, the system achieves high measurement precision for early-stage thermal runaway detection, identifying characteristic gases before they cause significant temperature or pressure changes.
Solution Approach 2:
The patent changes the detection parameter from temperature and pressure to optical spectral characteristics. By monitoring changes in light transmission through fiber Bragg gratings caused by gas absorption spectra, the system achieves superior detection precision for early thermal runaway events.
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 accurate and early detection of thermal runaway, allowing for mitigating actions before the condition becomes irreversible, reducing the risk of battery pack explosions and improving safety.
Implementation Method 1
the sensing fiber may comprise a filtering mechanism configured to reflect a portion of the spectrum of wavelengths of the light. In some embodiments, the filtering mechanism may be a fiber Bragg grating configured to reflect a reflected wavelength of the spectrum of wavelengths
Implementation Method 2
the sensing fiber may be optically coupled to a photodiode at the second end. In some embodiments, the gas may be detected based at least in part on an intensity of the light received at the photodiode
Implementation Method 3
the gas may impede a transmittance of the light within the transmitted spectrum of wavelengths according to a spectral signature
Data Source
AI summary
An example system, method, and computer program product for detecting thermal runaway in a battery cell is provided. The example system includes a light source configured to emit light across a spectrum of wavelengths toward a sensing fiber having a first end and a second end. The sensing fiber may be positioned to receive the light emitted by the light source at the first end. The sensing fiber may further contain a filtering mechanism configured to reflect a portion of the spectrum of wavelengths of the light. In addition, the sensing fiber may be optically coupled to a photodiode at the second end, such that a portion of the light is reflected as the light travels through the sensing fiber. The gas may be detected based at least in part on an intensity of the light received at the photodiode indicating the onset of thermal runaway.