Areacapacity is the three-chamber battery area per capacity in cm 2 /kWh. The value of Areacapacity can be calculated using 𝐴𝑆𝑅 0.2 𝑂𝐶𝑉 * 0.8 𝑂𝐶𝑉 * 𝑛 * 1000 . Ithree is the current density of the three-chamber battery cycling system in A/cm 2 . The value of Ithree can be estimated using . The equation above shows that the BPM recovery sub-cell capital cost is proportional to the acid-base crossover rate and is inversely proportional to the discharge duration at rated power and to the square of the OCV.