13 banks consisting of 65 modules
Each module of the battery includes two electrolyte tanks (cathode/anode), eight cell stacks (aggregates of membrane electrode composites), pipes for circulating electrolytic solution between the tanks and stacks, and heat exchangers. Five modules form one bank, and each bank is equipped with a PV inverter that controls charge and discharge (Fig. 5).
The cell is divided into cathode and anode by an ion exchange membrane that permeates hydrogen ions only, and charging and discharging are done by the exchange of electrolyte (vanadium ions) and electrons between the cathode and anode.
Thirteen banks (65 modules) are housed in the building. The DC power output from the cell stack is converted to AC power of 6.9kV by 13 PV inverters, and the power is boosted to 66kV by a transformer and is transmitted to a 66kV bus bar (extra-high-voltage transmission line) in the substation.
The "Tank-5-E-Cathode" indication on the tank near the entrance denotes the "cathode tank for the E module in the 5th bank."