Cell Swelling
Cell swelling is a phenomenon in li-ion batteries during its normal operation. Cell swelling solution enables the user to predict short-term and long-term mechanical effects on the li-ion batteries.
Swelling model – Short-term:
The short term/recoverable lithiation expansion is calculated as
where CLE1 is the Coefficient of Lithiation Expansion for short term/recoverable strain, SOC is the State of Charge of cell and initSOC is the initial SOC of the cell.
Short-term swelling is majorly dominated by recoverable strain and depends on SOC, temperature and charging rate. A short-term swelling solution is an extension of battery electro-thermal solution with a mechanical load case.
Swelling model – long-term:
The long term/unrecoverable lithiation expansion is calculated as
where CLE2 is the Coefficient of Lithiation Expansion for long term/unrecoverable strain.
Long-term swelling is dominated by unrecoverable strain and depends on time. Long term swelling is mechanical only load cases.
Swelling direction: Defines the direction of swelling strain.