Torch-and-Grit Material Testing for Battery Thermal Runaway
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Solution Overview
Problem
Existing systems lack effective methods for testing material samples under simulated battery thermal runaway conditions, particularly for lithium-ion cells, which are crucial for ensuring safety, longevity, and performance of battery materials.
Innovation Solution
A system comprising a fixture, two mixers for forming abrasive particle and combustible gas mixtures, temperature sensors, and a programmable logic controller to control flow rates and exposure conditions, simulating thermal runaway by projecting abrasive particles and flames onto material samples.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If material samples are tested under simulated thermal runaway conditions using flame and abrasive particles, then the evaluation of thermal and mechanical resistance is improved, but the device complexity increases
Solution Approach 1:
The testing system is divided into separate functional modules: a fixture for holding the material sample, a first mixer for preparing abrasive particle mixture, a second mixer for preparing combustible gas mixture, temperature sensors for monitoring, and a programmable logic controller for coordination. This segmentation allows each component to be optimized independently while maintaining overall system reliability for comprehensive material evaluation.
2Speed
If compressed air is mixed with abrasive particles at high velocity through a constricted section, then the kinetic energy and projection speed increase, but the static pressure decreases
Solution Approach 1:
The system uses a mixer with a constricted middle section where compressed air is mixed with abrasive particles. According to the principle of mass continuity, the velocity of the compressed air increases as it passes through the constricted section, while its static pressure decreases in accord with Bernoulli's principle. This pneumatic mechanism enables high-speed projection of abrasive particles onto the material sample for mechanical resistance testing.
3Quantity of substance
If the velocity of compressed air is increased to pull in more abrasive particles, then the amount of abrasive particles projected increases, but the static pressure differential becomes more negative
Solution Approach 1:
The programmable logic controller monitors and adjusts the velocity of compressed air to control the negative pressure differential at the port, thereby regulating the amount of abrasive particles pulled in. By adjusting the velocity of the compressed air, the negative pressure differential and thus the amount of abrasive particles pulled in can be adjusted, enabling precise control of particle quantity while managing pressure conditions.
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 thorough evaluation of material samples' thermal and mechanical resistance to battery thermal runaway, providing reliable performance data for selecting materials resistant to such events.
Implementation Method 1
a first mixer having a first chamber and a first channel, the first chamber being configured to mix compressed air with abrasive particles to form a first mixture having a first predetermined ratio between the compressed air and the abrasive particles, the first channel being configured to project the first mixture at a predetermined spot of the material sample during the test
Implementation Method 2
the ignitor located adjacent to an outlet of or protruding into the second chamber and configured to controllably ignite the combustible mixture to create a flame
Implementation Method 3
a first temperature sensor configured to measure a surface temperature of a side of the material sample unexposed to the flame during the test
Data Source
AI summary
An apparatus for testing a sample includes a fixture releasably holding the sample during a test, a first mixer having a first chamber and a first channel, the first chamber mixing compressed air with abrasive particles to form a first mixture having a first predetermined mixing ratio, the first channel projecting the first mixture at a spot of the sample during the test, a second mixer having a second chamber, an ignitor and a second channel, the second chamber mixing an oxidizer and a fuel to form a combustible mixture with a second predetermined mixing ratio, the ignitor adjacent to an outlet of or protruding into the second chamber and controllably igniting the combustible mixture to create a flame, the second channel projecting the flame at the spot during the test, and a first temperature sensor measuring a surface temperature of an unexposed side of the sample during the test.