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0 pointsmagicalhippo3mo ago0 comments

There was some research[1] that strongly suggested that varied use makes them last much longer than the steady use that most battery tests do. That is, bursts of high-current draw followed by moderate draw etc vs the constant current load typically used when evaluating battery performance. From the paper:

Specifically, for the same average current and voltage window, varying the dynamic discharge profile led to an increase of up to 38% in equivalent full cycles at end of life.

This was unexpected, hence explains why they fared better than predicted.

[1]: https://www.nature.com/articles/s41560-024-01675-8 Dynamic cycling enhances battery lifetime (open access)

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LordDragonfang3mo ago

Huh, unexpected is right. Bursts of heavy usage being better for longevity than steady usage goes against pretty much all conventional engineering wisdom.

abdullahkhalids3mo ago

Without knowing anything about it, I would posit that degradation accelerates the longer the battery is kept above some threshold temperature.

So, a heavy-burst+low results in a sudden high temperature then settling into a lower temperature. Steady flow keeps it at moderate temperature (above threshold) for a long time.

magicalhippoOP3mo ago

The paper notes there are multiple degradation mechanisms at play, and they are influenced by different factors, such as age, cycles, depth of discharge, state of charge at rest and so on. Hence the non-trivial response to more realistic discharge curves.

However they also note more material studies are needed to understand these mechanisms better.

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