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Traditional fire testing methods often require large samples, open flames, or complicated setups to study combustion. This technology introduces a compact, precise method using a Microscale Fire Calorimeter (MFC) that mimics realistic fire conditions with unprecedented control. When a solid material is thermally decomposed (pyrolyzed), it emits gaseous byproducts. These gases are then premixed with oxygen and combusted in the MFC’s reaction zone at high temperatures, without a visible flame. The MFC system precisely regulates oxygen availability, simulating different fire stages such as over-ventilated (oxygen-rich) and under-ventilated (oxygen-poor) conditions. This allows researchers to analyze how combustion chemistry changes as fires become more intense or oxygen-deprived. The system captures and quantifies the resulting gases and soot, enabling evaluation of environmental pollutants and toxic species produced during each combustion phase. This approach supports safer, smaller-scale laboratory testing while providing valuable data for applications such as material development, regulatory compliance, and forensic analysis. It bridges the gap between benchtop research and real-world fire scenarios.

Among the enhancements reflected in the Next Generation Li-ion Calorimeter is a rigidly wired system that allows direct mounting of thermocouples into key component locations to better capture thermal signature data during testing and improve thermocouple reliability. The ejecta mating chambers have also been modified for better thermal containment and easier system disassembly. Additionally, the system facilitates an easier access, user-friendly Destructive Physical Analysis (DPA) process between uses, and reflects durability improvements in the face of repetitive heat cycling. A clean-sheet redesign was undertaken to create a configurable insula-tion case with an interchangeable “window” section, tailored to the ex-perimental environment. For NASA’s Energy Systems Test Area (ESTA) evaluation, a window with the original foam is installed to maintain ther-mal insulation performance. In contrast, for synchrotron experiments, this section is replaced with an aluminum window that eliminates foam-related X-ray scattering. This modification has substantially improved X-ray radiography resolution, enabling clearer imaging of fine internal battery features during thermal runaway events. Moreover, the insulation case was designed to provide system fire-proofing for both the chamber and pouch cell testing case configurations. Lastly, a control switchbox is also being developed to work with the latest generation calorimeter. It allows users to remotely operate the TR trigger mechanism from a control room, automatically terminate power in a prescribed amount of time to prevent a fire caused by overheating, and provides lit indicators to inform the user of ready or fault states.

Thermal runaway analysis provides unique insights into TR by allowing researchers to tally the total thermal energy release, plus the energy fractions liberated by venting, and energy that conducts through a cell casing – such as that of a 4Ah Amprius cell, or a 10Ah SVolt cell – both for which the ABCC was originally designed to accommodate. This unique data is important in understanding Li-ion battery thermal design and analysis which may ultimately lead to safer Li-ion batteries with increased resistance to TR. The ABCC is designed to work in tandem with the FTRC when coupled together for TR testing: The battery test subject is first sandwiched between the two chamber halves, or diaphragms, and then secured with fasteners. The ABCC – which in different embodiments may have varying outlet diameters depending on battery sizing – is then coupled to the FTRC bore assembly using unique adapters and the aforemen-tioned pin system. A threaded port is centered on both diaphragms to accommodate one of several TR trigger mechanisms, such as a 400-watt heating element or a nail penetrator with a 9mm insertion depth. With the main hardware assembled, the user can leverage the ABCC’s configurability into deciding to either rely solely on external instrumen-tation within the bore and baffle assembly (external of the ABCC), or to utilize the ABCC’s already tapped sensor ports to install thermocouples in a variety of different geometric layouts to provide better resolution of thermal measurements. Wiring can be run through the “battery cell connector support” to its multi-pin circular connector. After initiating TR in the battery cell, the FTRC will absorb the ejecta and gases expelled by ABCC for analysis. The Adaptive Battery Cell Chamber is at TRL 6 (system/subsystem model or prototype demonstrated in a relevant environment), and it is now available for licensing. Please note that NASA does not manufacture products itself for commercial sale.