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To save everyone the hassle of filling out the "get the report" form: https://7802750.fs1.hubspotusercontent-na1.net/hubfs/7802750/White%20Papers%20and%20Guide

To save everyone the hassle of filling out the "get the report" form: https://7802750.fs1.hubspotusercontent-na1.net/hubfs/7802750/White%20Papers%20and%20Guides/Batteries/Lumafield%20Battery%20Report.pdf https://7802750.fs1.hubspotusercontent-na1.net/hubfs/7802750...

nom 1y ago
thank you
gertlex 1y ago
FWIW I found the report's summary (a few days ago when this was also discussed) essential for clarifying for me what the linked "article" was talking about regarding "anode overhang" and "edge alignment". To summarize it myself, the battery is cylindrically wrapped sheets of anode/cathode material, and you want the top edge to have a straight line consistently having the anode layers (|) sticking out beyond the cathode layers () edit: Welp, the unicode I illustrated with got stripped out; so trying again with pipes anode cathode a a c c | | | |||||| The pics with red and blue dots didn't immediately make this obvious to me, but made sense once I understood the "overhang" meaning.
- MBCook 1y ago
  So the big danger here is an internal short being far more likely?
  - gertlex 1y ago
    That was my general sense. And that "nominal" is really easy to identify visually with a (relatively slow) scan. I'd guess that means it's a clear quality control thing you (i.e. battery pack makers who are buying the cells) can expect the better manufacturers to do, and pay a slight premium for.
  - dpedu 1y ago
    I seem to recall this being a factor in the Samsung Galaxy Note 7 battery fire debacle. The article linked below has an xray image where you can see the anode/cathode overhanging and then being shorted by subsequent damage. https://www.theguardian.com/technology/2017/jan/23/samsung-blames-faulty-batteries-for-causing-galaxy-note-7-fires#img-2 https://www.theguardian.com/technology/2017/jan/23/samsung-b...
- stavros 1y ago
  Is this what's shown in the photo here? https://imgz.org/i55rjGiq/ https://imgz.org/i55rjGiq/
  - gertlex 1y ago
    Yep! where the green arrow is pointing is what I was ascii-lustrating

nom 1y ago

thank you

gertlex 1y ago

FWIW I found the report's summary (a few days ago when this was also discussed) essential for clarifying for me what the linked "article" was talking about regarding "anode overhang" and "edge alignment". To summarize it myself, the battery is cylindrically wrapped sheets of anode/cathode material, and you want the top edge to have a straight line consistently having the anode layers (|) sticking out beyond the cathode layers () edit: Welp, the unicode I illustrated with got stripped out; so trying again with pipes anode cathode a a c c | | | |||||| The pics with red and blue dots didn't immediately make this obvious to me, but made sense once I understood the "overhang" meaning.

MBCook 1y ago
So the big danger here is an internal short being far more likely?
- gertlex 1y ago
  That was my general sense. And that "nominal" is really easy to identify visually with a (relatively slow) scan. I'd guess that means it's a clear quality control thing you (i.e. battery pack makers who are buying the cells) can expect the better manufacturers to do, and pay a slight premium for.
- dpedu 1y ago
  I seem to recall this being a factor in the Samsung Galaxy Note 7 battery fire debacle. The article linked below has an xray image where you can see the anode/cathode overhanging and then being shorted by subsequent damage. https://www.theguardian.com/technology/2017/jan/23/samsung-blames-faulty-batteries-for-causing-galaxy-note-7-fires#img-2 https://www.theguardian.com/technology/2017/jan/23/samsung-b...
stavros 1y ago
Is this what's shown in the photo here? https://imgz.org/i55rjGiq/ https://imgz.org/i55rjGiq/
- gertlex 1y ago
  Yep! where the green arrow is pointing is what I was ascii-lustrating