Fiber Bragg Grating Gas Sensing 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 hazardous conditions due to their reliance on temperature and pressure sensors, which provide alerts too late and can result in false alarms or propagation of overheating to adjacent cells.
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 signatures analyzed by a processor that may employ machine learning techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
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 false alarms occur
Solution Approach 1:
The patent replaces traditional mechanical 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 conditions before temperature and pressure changes become significant.
Solution Approach 2:
The system monitors changes in gas composition parameters (ethylene carbonate, diethyl carbonate, dimethyl carbonate) rather than waiting for temperature or pressure parameters to change. By detecting the spectral signatures of these gases at their source, the system identifies thermal runaway conditions at an earlier stage, reducing detection time and improving reliability.
2Measurement precision
If multiple sensing fibers with different filtering mechanisms are used, then gas detection accuracy is improved, but device complexity increases
Solution Approach 1:
The patent divides the detection system into multiple specialized sensing fibers, each equipped with filtering mechanisms tuned to detect specific gas components (ethylene carbonate, diethyl carbonate, dimethyl carbonate). This segmentation allows each fiber to focus on a particular spectral range, improving detection accuracy for individual gases while maintaining overall system manageability through modular architecture.
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 by identifying gas signatures indicative of battery decay.
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
a sensing fiber comprising a first end and a second end. In some embodiments, the sensing fiber may be positioned to receive the light emitted by the light source at the first end. Further, in some embodiments, the sensing fiber may be optically coupled to a photodiode at the second end. In addition, 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. In such an embodiment, the plurality of sensing fibers may be configured to identify the gas according to the spectral signature of the gas
Data Source
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AI summary
System (100, 200), method, and computer program product for detecting thermal runaway in a battery cell (208) is provided. The system (100, 200) includes a light source (114, 202) configured to emit light (112, 204, 206) across a spectrum of wavelengths toward a sensing fibre (104a-104d, 400) having a first end (102a-102d, 406) and a second end (418). The sensing fibre (104a-104d, 400) may be positioned to receive the light (112, 206) emitted by the light source (114, 202) at the first end (102a-102d). The sensing fiber (104a-104d) may further contain a filtering mechanism (406) configured to reflect a portion of the spectrum (408) of wavelengths of the light. In addition, the sensing fibre (104a-104d, 400) may be optically coupled to a photodiode (106a-106d) at the second end (418), such that a portion (412) the light is reflected as the light travels through the sensing fibre (104a-104d, 400). The gas (210) may be detected based at least in part on an intensity of the light received at the photodiode (106a-106d) indicating the onset of thermal runaway.