<p>Fast charging is crucial to the proliferation of electric vehicles.
Fast charging is limited by lithium plating, which is the deposition of lithium
metal on the anode surface instead of intercalation of lithium into the anode. Lithium
plating causes capacity fade, increases cell resistance, and presents safety
issues. A fast charging strategy was implemented using a battery management
system (BMS) that avoided lithium plating by predicting the anode impedance. Commercial
pouch cells modified with a reference electrode were cycled with and without
the BMS. Cells cycled with the BMS avoided lithium plating but experienced
significant degradation at the cathode. Cells cycled without the BMS underwent
extensive lithium plating at the anode. Capacity loss was differentiated into
irreversible and irretrievable capacity to understand electrode-based
degradation mechanisms. Post-mortem analysis on harvested electrodes showed
that the BMS cycled cells exhibited minimal anode degradation and had a
two-times higher capacity loss on the cathode. The cells cycled without the BMS
had extensive anode degradation caused by lithium plating and a seven-times
higher capacity loss on the anode. </p>
<p> </p>
<p>Understanding and preventing the aging mechanisms of lithium-ion
batteries is necessary to prolong battery life. Traditional full cell measurements
are limited because they cannot differentiate between degradation processes
that occur separately on anode and cathode. A reference electrode was inserted
into commercial cylindrical lithium-ion cells to deconvolute the anode and
cathode performance from the overall cell performance. Two configurations of
the reference electrode placement inside the cell were tested to find a
location that was stable and had minimal interference on the full cell
performance. The reference electrode inside the mandrel of the cylindrical cell
had stable potential measurements for 80 cycles and at different C-rates and
had minimal impact on the full cell performance.<b></b></p>
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/14496039 |
| Date | 06 May 2021 |
| Creators | Amy M Bohinsky (10710579) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY 4.0 |
| Relation | https://figshare.com/articles/thesis/Operando_Degradation_Diagnostics_and_Fast_Charging_Analytics_in_Lithium-Ion_Batteries/14496039 |
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