Ram-Dent Thermal Runaway Triggering Device

The Ram-Dent Thermal Runaway Triggering Device is capable of trig-gering mild short circuits that are similar to internal defects, and more extreme short circuits that are comparable to those initiated by an implanted internal short circuit device – all without having to modify the battery cell in any way. The device imparts a high velocity, low mass blunt impact onto a small surface area of a Li-ion battery cell can wall allowing a small hemispherical dent to form. This impact deforms and tears the internal separator of the battery cell, causing a short circuit, and induces thermal runaway. Several methods for initiating TR on demand currently exist, but they have characteristics and biases that make them more unfavorable for certain testing objectives. Heat-based insult in any form requires additional thermal energy to be applied to the battery cell, potentially distorting the signal-to-noise ratio in FTRC measurement, and increas-ing the severity of failure beyond what is intended. This methodology also requires time to heat the battery cell to critical temperature, and it potentially weakens the battery cell can wall causing abnormal kinetics and rupture. Mechanical insult methodologies, such as crush testing and nail penetration, have unique applications but rely on deformation of the battery cell itself which alters the flow characteristics of internal gases and the material integrity of the battery cell. This technology aims to solve these limitations by implementing a cost-effective method to create a natural short circuit failure in Li-ion batteries that does not alter nominal vent paths and energy yields, potentially yielding the most unbiased calorimeter tallies yet. The Ram-Dent Thermal Runaway Triggering Device is at a technology readiness level (TRL) 4 (component and/or breadboard validation in laboratory environment) and is now available for patent licensing. Please note that NASA does not manufacture products itself for commercial sale. Innovators at NASA Johnson Space Center have developed a device that projects a dome-ended nail at a Li-ion battery cell can wall to initiate a thermal runaway (TR) event by denting it. The dent and resulting internal stress wave tears the separator between the anode and cathode within the battery cell causing a short circuit that leads to TR and battery deflagration. Initiating TR in battery cells is an important part of Li-ion battery R&D to better understand the effects of TR, and to make related safety improvements. The novelty of this technology is that the separator is destroyed from the inside without perforating the battery cell can itself or adding thermal energy as a trigger mechanism. This approach results in a more accurate simulation of field-like short circuits and TR for Li-ion battery research and development compared to current state of the art (SoT). Additionally, this device could be used to enhance or supplant traditional testing methods such as those that implement heat-based TR initiation, or mechanical insult where the material integrity of a battery cell is compromised. The Ram-Dent Thermal Runaway Triggering Device was designed to be used in conjunction with NASA’s fractional thermal runaway calorimeters (FTRC) to obtain calorimetry measurements of TR events for fast Li-ion battery failure evaluation. However, this device could be modified to work with other calorimeters designed for the testing of a single Li-ion battery cell or battery-pack.