“Searching for a pulse”: How CT can identify safety risks that electrochemistry misses

Glimpse’s work with the National Renewable Energy Laboratory (NREL) was just published! Led by Paul Gasper, the publication is entitled “Searching for a Pulse: Evaluating the Use of Rapid DC Pulses for Diagnosing Battery Health, State-of-Charge, and Safety” and was published in the Journal of the Electrochemical Society. You can read the paper here and view the scans on the Glimpse Portal here.

CT scan images highlighting safety risks identified in both cylindrical and prismatic cells. Reproduced from Figure 3 of Gasper et al.

The goal of this paper was to evaluate the effectiveness of electrochemical pulses to evaluate key battery metrics such as state-of-charge (SOC), state-of-health (SOH), and safety. The promise of this technique is that these rapid pulses could be an inexpensive way to probe battery behavior, especially for second-life applications. To test this technique, NREL acquired a variety of aged cells from cars and buses in use across the US and tested them via electrochemical pulses. Glimpse also CT scanned some of these cells to evaluate their safety and reliability.

The result is clear: While rapid electrochemical diagnostics can reliably predict SOC and capacity, they are wholly inadequate for identifying safety risks. See the below quote from the conclusion of the article:

...we show a complete failure to detect any potential safety and reliability issues that we identified via post-charge voltage relaxation analysis, physical inspection, and XCT scanning. These findings highlight the critical need for the development of fast and accurate methods for non-destructive safety and reliability diagnosis of battery systems.

CT scanning is the best technique to detect cell safety and reliability issues — both latent and already present — and Glimpse is pioneering high-throughput CT to enable battery quality at scale. Contact us to leverage high-throughput, high-quality CT scanning to evaluate cell quality.