A battery is considered to be deeply discharged when its residual voltage drops below a certain level, the so-called "end-of-discharge voltage". This voltage is very individual for different cell chemistries (NMC, LFP, LTO): Lithium polymer batteries (3.3V) or NMC cells (2.5V to 3.0V) are considered to be particularly susceptible to internal structural damage, which affects all cell components from the anode to the cathode during deep discharge.

While the famous nickel-manganese-cobalt cells quickly show irreversible damage and loss of capacity during deep discharge, LFP cells (2.0V) are considered to be relatively resistant to material and cell damage that can occur during deep discharge.

A study on lithium titanate battery cells (LTO) from 2022 also confirms that LTO cells have a particularly high resistance to material changes during deep discharge. In the publication, deeply discharged cells showed surprisingly little loss of capacity over a period of 84 days after multiple deep discharges to 0 volts.

The following gases cause the famous "bloating" of the pouch cells: oxygen, hydrogen, carbon monoxide, carbon dioxide and occasionally methane.

The causes of deep discharge can be varied: from battery use to defects in the #battery management system to extremely low temperatures.

In contrast to small batteries (#cell phone, #laptop, #power bank), large, modern electric cars with their BMS are designed to reliably prevent deep discharge: automatic shutdowns, protective switches, charging windows and buffer emergency reserves ensure that electric cars practically never deeply discharge in everyday life.

Andreas Schmitz on the deep discharge of lithium cells:
   • 0V Lithium Zellen wiederbeleben: Dies...  

Mechanism of the entire overdischarge process and overdischarge-induced internal short circuit in lithium-ion batteries:
https://www.nature.com/articles/srep3...

"Li-Ion Battery Deep Discharge Degradation" by Petr Prochazka et.al.:
https://iopscience.iop.org/article/10...

Jonathon R Examining the Performance of Implantable-Grade Lithium-Ion Cells after Overdischarge and Thermally Accelerated Aging (2022):
https://www.mdpi.com/1996-1073/15/4/1405

Podcast episode with Dr. Kai-Philipp Kairies (Accure):
https://geladen.podigee.io/140-batter...

Battery Generation podcast episode with Prof. David Howey:
https://batterygeneration.podigee.io/...

In the Geladen podcast, Patrick Rosen and Daniel Messling and their guests scientifically examine the topics of #energy transition, #electromobility, #electric cars and #batteries. The podcast is produced by the Karlsruhe Institute of Technology (KIT).

Geladen mugs, shirts & caps: https://geladen-der-batteriepodcast.m...
Instagram:   / geladenpodcast  
All links: https://linktr.ee/geladen