Here are the graphs of first charging and discharging runs. The battery was loaded with 500mA current sink during discharge and supplied from 13V (1Alimit) voltage source during charging.
During discharge the converter passes trough three modes. First is the constant output voltage. As the battery voltage drops, the battery current rises to the maximum limit. At that point the converter enters into maximum current regulation and the output voltage starts to fall. As the battery voltage reaches minimal value of 2.8V the maximum current starts to be lowered to avoid over discharge at that point the output voltage falls even lower and the test is stopped when the current falls below 10% of maximum value.