javascriptTO REWORK
Prior to testing cell capacity, we should qualify the cells according to their IR and voltage
- Voltage:
- V < 2.5V cells should not pass to next step (update: not true)
- Cells < 2.0V should go to recycling straight away
- We could later try to revive > 2.0V cells if considered profitable despite the risks
- “Li-ion cannot dip below 2V/cell for any length of time. Copper shunts form inside the cells that can lead to elevated self-discharge or a partial electrical short. (See BU-802b: Elevated Self-discharge) If recharged, the cells might become unstable, causing excessive heat or showing other anomalies. Li-ion batteries that have been under stress may function normally but are more sensitive to mechanical abuse.” (source : Battery University)
- Internal Resistance:
- IR > 90 mOhm is rejected (value depends on cell model)
- A lot of articles mention the “200% increase” criteria
Exact values TBD
How does the IR relate to its nominal value on an old cell ? @
Test old cells and read papers on the subject
📰 Review of scientific papers:
Our grading method: 1mΩ mismatch seems to be a good trade-off
⚠️ Neware accuracy: 0.05% on voltage and current ⇒ 0,071% on IR ⇒ fine
Reviving low voltage cells