Schmeid Vanadium Redux Flow Battery

Overview

• Composed of two tanks storing vanadium analyte and catholyte.
• Pumps flow electrolytes through adjacent half-cells separated by an ion exchange membrane.
• Converts electrical energy to chemical energy and vice versa.
• Uses external power source (e.g., PV installations) for charging.

Charging Process

1. Electrolyte Flow:
   • Vanadium electrolytes flow through the cell stack.
   • Electrical energy is converted to chemical energy.
2. Molecular Reactions:
   • In the cathode half-cell:
     • Vanadium 4 (V4) is oxidized to Vanadium 5 (V5).
     • Produces an electron and a hydronium ion (H3O+).
   • The electron travels through the conductive electrode material.
   • The hydronium ion diffuses across the membrane to the anode half-cell.
3. Anode Reaction:
   • Electron reduces Vanadium 3 (V3) to Vanadium 2 (V2).
   • Hydronium ion balances charge.
4. Charged State:
   • Electrolytes exit half-cells as V2 and V5.

Discharging Process

1. Swapping to Discharge:
   • When the grid can't provide power, battery discharges.
2. Chemical Energy Conversion:
   • V5 and V2 ions carry chemical energy into the cell stack.
3. Molecular Reactions:
   • In the cell stack:
     • V2 is oxidized to V3, releasing an electron.
     • H3O+ crosses the membrane.
     • V5 is reduced by consuming an electron and H3O+.
4. Discharge State:
   • Electrolytes leave the cell as V3 and V4.

Advantages

• Scalability:
  • Power adjustable through cell size and number.
  • Energy defined by tank volume.
• Longevity:
  • No loss in power/capacity due to side reactions.
  • Superior lifetimes compared to conventional batteries.
  • Deep discharge does not affect battery health.
• Non-contamination:
  • All-vanadium setup eliminates cross-contamination issues.
• Safety and Ecology:
  • Low hazard potential with vanadium salts in dilute sulfuric acid.
  • Best possible ecological properties.
• Cost-Effectiveness:
  • Low production costs ensuring viability for renewable energy storage.