Innovators at NASA Johnson Space Center have developed a method to measure the total and fractional heat response of large format Li-ion cells (cells with capacities greater than 100Ah) when driven into thermal runaway conditions. The new hardware can handle up to 40 times the energy yield of a small format iteration. By understanding the thermal runaway behavior of larger Li-ion cells, engineers can gain insight to improve the design of both the cell and battery level. This in turn helps prevent cell-to-cell propagation during a cell explosion, reducing both consequence of failure as well as the likelihood of loss of hardware or mission.
The Large Format Thermal Runaway Calorimeter (L-FTRC) implements a novel basket capture system designed to facilitate the direct capture and temperature measurement of a completely ejected electrode winding a common occurrence in a thermal runaway event for cells of this size. The L-FTRC also makes use of new strain relief techniques for all associated instrumentation, improving measurement reliability. The system provides a gas collection system capable of capturing the expelled gases in a manner that provides the means to analyze the overall volume of expelled gases, as well as flowrate, temperature, and chemical composition.
This design enables a novel overall capability. Large format Li-ion battery manufacturers can now benefit from testing their batteries for aerospace, automotive, military, and other heavy-duty commercial applications using this technology.