Battery Degradation and Performance

Impact of Check-up Cycles on Calendar Aging Cells with silicon–graphite anodes and Ni-rich layered-oxide cathodes are a key next-generation high-energy Li-ion architecture, but their calendar-aging response differs from conventional commercial cells, motivating updated design and operating strategies for lifetime and safety.In Si-graphite/Ni-rich Li-ion cells, check-up frequency strongly influences calendar aging. 15-day check-ups caused 2× more capacity loss than 90-day check-ups after 200 days of storage. Storage charging method (open-circuit, daily charge, float) had minimal impact on capacity fade, check-up frequency dominates. Calendar and cycle aging are coupled, not linearly additive. Diagnostics Differential Voltage Analysis) indicate dominant modes are LLI Si-anode LAM. More frequent check-ups delayed CID Current Interrupt Device) activation, likely due to pressure relief during cycling and cool-down.

Capacity fade over time of cells with different check-up frequencies and cells aged with cycle test

Evolution of different ageing modes with time. (a) LLI, (b) LAM in silicon, (c) LAM in anode, (d) LAM in graphite and (e) LAM in cathode.

Minimize and standardize check-up intervals, and always report them. Otherwise, you may be measuring check-up–induced degradation rather than true calendar aging. Source: Laresgoiti, I., Yi, H., Koster, D., Karimi, F., Yang, J., Schulte, D., & Figgemeier, E. 2024. Calendar ageing of commercial 18650 cells with nickel-rich cathode and graphite-silicon anode: Influence of check-up. Journal of Energy Storage, 98, 112918.

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