Effects of hydrostatic pressure and modulus softening on electrode curvature and stress in a bilayer electrode plate

• Numerical solutions of curvature and DIS in a bilayer electrode plate are obtained.
• Modulus softening reduces DIS and makes electrode bend easy for potentiostatic.
• Electrodes reach a lock-up state or bend continuously for different charge process.
• Thicker or higher rigidity of current collector blocks Li-ion diffusion.
• Charge process for reduced bending is galvanostatic first potentiostatic followed.

The effects of hydrostatic pressure and modulus softening on electrode curvature and stress in a bilayer electrode plate are studied. It is found the hydrostatic pressure facilitates Li-ion diffusion. Modulus softening can weaken the stress assisted diffusion, promote the electrode to bend and reduce the stress. The electrode would nearly reach a lock-up state of deformation in the late charging process for potentiostatic charging, but the electrode bends continuously for galvanostatic charging. It is also found the electrode curvature firstly increases, and then reduces as current collector thickness increases, but decreases continuously by increasing the modulus of current collector. The thicker current collector and higher rigidity of current collector can block Li-ion diffusion for potentiostatic charging. Finally, the optimized charging procedure for reducing the bending deformation is galvanostatic first followed by potentiostatic, the current collector should be as thin and soft as possible when its own strength and role are satisfied.