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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.

The Thermal Ejecta Shielding System comprises strategically layered materials that fasten to the top of a Li-ion cylindrical battery pack casing. It can protect individual battery cells in a battery pack by shielding them from a neighboring cell’s hot thermal ejecta during a TR event while providing primary functions of connecting, insulating, grounding, and distributing power. In laboratory testing, this technology improved the resistance to TR collateral damage of a PPR battery pack by overcoming two primary drawbacks of its design. Modern Li-ion cylindrical battery cell packs comprise a nickel bus plate that aligns with and connects the positive buttons along the battery tops to distribute power. Insulating G10 composite layers sandwich the bus plate atop the cells, however, these are rendered vulnerable to burn-through during a TR event due to their thinness, and they can allow escaping thermal ejecta to penetrate the button cavities of neighboring battery cells within the battery pack. Additionally, the nickel and composite bussing layering is prone to separation, or "tenting", when subjected to extreme heat, as it relies solely on an adhesive bond to prevent delamination. The hot ejecta spray stemming from a battery cell undergoing a TR event can weaken this adhesive bond. These issues can lead to adjacent battery cell damage resulting in their reduced performance, zero-voltage, or susceptibility to a larger TR event. The Thermal Ejecta Shielding System for Li-ion Battery Packs was developed from a multi-pronged strategy to improve upon the drawbacks by introducing these novel components and accompanying features: • Capture Plate Cell “Chimney” - Redirects ablative ejecta away from adjacent cells and creates a volume for liquid “sealer” protection; • Adhesively Backed Mica Cell Donut - Provides an insulative layer to protect the positive bus plate from creating a short circuit to the negative cell can during TR; • Adhesive Transfer Tape - Provides an adhesive layer for a more uniform/reproducible bond between the nickel bussing, mica, the G10/FR4 insulating layer, and the aluminum layers; • Continuous Mica Cell Cover Sheet - Replaces individually installed mica covers (upper layer of G10/FR4) with a single sheet of perforated mica; • Rupture Sheet Cover Plate - Introduces a thin aluminum fastener plate above the Continuous Mica Cell Cover Sheet to prevent delamination of bussing sandwich layers; • Narrowed Bus Plate Tab - Introduces a narrowed tab to allow for unrestricted header expansion and severing/separation during TR; • Steel Ring - Protects cell from spin groove ruptures and redirects ablative ejecta away from adjacent cells; and • Liquid Cell Covers - Introduces a high temperature liquid “sealer” to fill the void between cell button and mica cover to prevent ejecta burn-through from compromising the seal.