The manufacturer of 18650 lithium-ion battery cells matters a lot: The Lumafield Battery Quality Report
Posted by jpluimers on 2026/06/09
A very important report from September 2025 for users of 18650 lithium-ion battery cells: [Wayback/Archive] The Lumafield Battery Quality Report.
Summary:
… beneath the surface, a hidden world of quality control issues and dangerous counterfeits puts consumers and manufacturers at risk.
…
Our automated analysis focused on key indicators of cell safety and quality, including anode overhang (AOH) and edge alignment, two critical factors that directly impact battery performance and safety.
…
Flawed anq quality battery cells:
…
While most major original equipment manufacturer (OEM) batteries showed few major flaws, the rewrapped and low-cost batteries showed seven times greater deviation in anode overhang and much worse edge alignment in their internal wound layers.
…
It looks like you basically need to aim for cells of these manufacturers, ordered through reputable channels to lower the risk of counterfeits. This list is based on smallest anode overhang, extracted from the below graph I borrowed from the report page:
Grouped Ranking of Smallest Anode Overhang Measurement per 18650 Cell Small gap,
small deviation spreadLess small gap,
small deviation spread:Larger gap or large deviation spread
- Samsung
- Vapcell
- Murata
- Panasonic
- Efest
- Trustfire
- SOOCOOL
- Treasurecase
- Maxiaeon
- Benkia
From left to right and top to bottom, the situation gets worse.
I extracted that table from the graph on the report page:
Smallest Anode Overhang Measurement per 18650 Cell (mm)
Via: [Wayback/Archive] The Surprising Flaws in 18650 Lithium-Ion Batteries – YouTube
Related:
- [Wayback/Archive] Lumafield Battery Report.pdf
- [Wayback/Archive] October Fire Report
- [Wayback/Archive] Behind the Battery Report
--jeroen
The Wiert Corner - irregular stream of stuff 
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