1. Basic properties and characteristics of Li-ion batteries
1.8. Degradation and aging
- Natural aging - the battery loses capacity spontaneously after a few years and fails without drawing power.
- Tunneling of electrons through SEI into the electrolyte.
- The electrons react with the electrolyte and form additional layers SEI → SEI increases and the electrolyte is gradually consumed.
- This process is significantly accelerated when the battery is used and current is drawn.
- Li+ passing through the electrolyte → entrains solvent molecules → reacts with tunneling electrons → SEI layer grows → electrolyte and lithium are consumed → battery destruction.
Christoph R. Birkl, Matthew R. Roberts, Euan McTurk, Peter G. Bruce,
David A. Howey: Degradation diagnostics for lithium ion cells, Journal
of Power Sources 2017, Elsevier