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Featured New Study: Charging Lithium Ion Batteries at High Currents for the First Time is Good

Discussion in 'Prius, Hybrid, EV and Alt-Fuel News' started by drash, Aug 31, 2024 at 8:46 PM.

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  1. drash

    drash Senior Member

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    https://www.greencarcongress.com/2024/08/20240830-slac.html
    From the SLAC-Stanford Battery center, the very first charge for a Lithium Ion battery cell actually should be at a rather high currents which increased their average lifetime by 50%. Now I'm curious.

    Darn, now that made me read the original article:
    Researchers discover a surprising way to jump-start battery performance
    Typically battery manufacturers use a low energy charge to try and control the SEI layer build up. It's also a slow and costly way to do this. So they went brute force and attempted to use up a large initial supply of lithium during the batteries first charge by creating the SEI (Solid Electrolyte Interphase) with very high currents.

    I wasn't too keen on their analogy of comparing it to scooping out water from a bucket to keep it from spilling over. More than likely has something to do with getting the higher energy lithium ions to stick first in the SEI which prevents lower energy ones from clogging up the SEI and not migrating back to the positive electrode. Research isn't quite finished so I could be wrong. Lots of unknowns like how hot did the battery get, what was the cool down before discharging, and is this true for NMC, LiFePO4, NCA.

    Special note - I wouldn't try this at home. Sounds like someone might try and use charge mode for the first time when they drive their Prime from the dealer or visit a fast charger for their EV. It has to be the first charge, not your first charge.

    BTW this was funded by Toyota Research Institute.
     
    #1 drash, Aug 31, 2024 at 8:46 PM
    bwilson4web likes this.
  2. bwilson4web

    bwilson4web BMW i3 and Model 3

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    I knew about the initial charge/discharge cycle as part of the manufacturing. Just I find it strange no one else found this before. Given how much research has gone into LiON battery research, how this escaped notice seems "odd." From the abstract:

    Formation is a critical step in battery manufacturing. During this process, lithium inventory is consumed to form the solid electrolyte interphase (SEI), which in turn determines the battery lifetime. To tackle the vast parameter space and complexity of formation, we employ a data-driven workflow on 182 lithium-ion battery cells across 62 formation protocols. We identify two key parameters, formation charge current and temperature, that control battery longevity via distinct mechanisms. Surprisingly, high-formation charge current on the first cycle extends battery cycle life by an average of 50%. Unlike elevated formation temperature, which boosts battery performance by forming a robust SEI, the cycle life improvement for fast-formed cells arises from a shifted electrode-specific utilization after formation. Apart from the widely acknowledged role of formation in governing SEI properties, we demonstrate how formation protocols determine the stoichiometry range over which the positive and negative electrodes are cycled.

    upload_2024-8-31_22-2-42.png
    ​
    I suspect the 182 is just the size of the test cells. We don't know what chemistry and electrodes were used. Also, this would stress the separator. Shorting the separator, shorts the cell making it junk

    I need to read the paper:
    upload_2024-8-31_21-56-41.png

    Bob Wilson
     
    #2 bwilson4web, Aug 31, 2024 at 10:50 PM
    Last edited: Aug 31, 2024 at 11:07 PM
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