Reference example (video) courtesy : UCL (University College London)
Thermal runaway is a potentially hazardous situation in which an escalation in temperature can result in fires or explosions, especially in lithium-ion batteries.
Laboratory simulations use advanced techniques, such as X-ray imaging and in-situ measurements, to study the intricate details of these phenomena.
Lab Simulations and analysis:
1. Controlled Environment:
An isolated chamber is used to control variables like temperature, pressure, and humidity during tests.
2. Inducing Conditions:
Methods employed can include external heating, overcharging, creating short circuits, or physically abusing the device.
3. X-ray Imaging:
-Real-time Insight: Using X-rays during the simulation allows researchers to view internal structural changes in the battery or device without disrupting the experiment.
-Electrode Behavior: X-rays can capture electrode deformations or fractures, which might lead to internal short circuits.
-Gas Evolution: Bubbles and gas pockets formed during thermal runaway can be visualized, giving insights into the decomposition processes.
4. In-situ Measurements:
-Continuous Monitoring: In-situ techniques may involve placing sensors directly inside the battery or device, providing continuous real-time data.
-Internal Temperature Gradients: While external sensors measure overall temperature, in-situ sensors can detect temperature variations within the device.
-Voltage and Current: Monitoring these parameters in real-time helps identify the onset and progression of thermal runaway.
-Electrochemical Analysis: In-situ electrochemical cells can be used to study the changes in battery chemistry during the test.
5. Measurement Tools:
Apart from X-ray tools and in-situ sensors, labs may use thermal cameras, pressure sensors, and other diagnostic tools.
6. Outcome Analysis:
After the test, researchers analyze the samples using microscopic analysis, chemical assays, X-ray imaging, and data from in-situ measurements.
Benefits of Advanced Techniques:
1. Detailed Insights: X-rays and in-situ measurements offer a granular view of the internal happenings during thermal runaway, which can be crucial for understanding the root causes.
2. Better Predictions: With real-time data, researchers can model and predict potential failure scenarios more accurately.
3. Improved Safety: By gaining a deeper understanding of failure mechanisms, manufacturers can design safer batteries and electronic devices.
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