Battery Technology - May 2021 - 8

Accelerated
Degradation of
Li-Ion Batteries for
High-Rate Discharge Applications

T

he U.S. Army has been pursuing vehicle electrification to achieve enhanced combat effectiveness. The benefits include new capabilities that
require high-power pulse duty cycles. However,
as the vehicle platform size decreases, the Energy Storage System (ESS) pulse power discharge rates (>40 C-rate) to support system requirements can be
significantly greater than commercial ESS.
Results are reported of high-power pulse duty cycles on lithium-iron phosphate cells that show a dramatic loss in lifetime
8

performance. For two-second and three-second pulse duration
tests, the observed degradation is 22% and 32%, respectively. Although these cells were thermally managed in a convective
chamber at 10 °C, the 2-second pulse showed a 31 °C temperature rise and the 3-second pulse a 48 °C temperature rise.
The decreased lifetime is attributed to increased lithium loss
due to the increased temperature during pulse discharging. To
mitigate the thermally induced degradation, the use of different
thermal management systems and alternative cell design is discussed and recommended.
Battery Technology, May 2021

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Battery Technology - May 2021

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