Vanadium batteries, also known as vanadium redox flow batteries, have seen a surge in popularity in June 2022, as the National Energy Administration issued a document seeking public opinion. This document aims to ensure the safety of energy storage power stations and proposes that medium and large-scale electrochemical energy storage power stations should not use ternary lithium batteries or sodium-sulfur batteries.
Which is better, vanadium batteries or lithium batteries?
1. Safety: The core reason why vanadium batteries have gained such popularity is their safety. From 2011 to April 2022, a total of 34 energy storage power station explosions occurred globally, of which 32 involved lithium batteries, and one each involved lead-acid batteries and sodium-sulfur batteries.
2. Cycle life: Lithium-ion batteries have a short cycle life, with lithium iron phosphate batteries for energy storage having a maximum cycle life of about 6,000 times, while vanadium batteries have a very long life, with a cycle life of 10,000 to 20,000 times;
3. Energy Density: Vanadium batteries have a low energy density, only 12~40Wh/kg, mainly limited by the solubility of vanadium ions and stack design. Lithium batteries, on the other hand, typically have an energy density of 80-300Wh/kg. Therefore, to achieve the same storage capacity, vanadium batteries would undoubtedly need to be much larger, 3-5 times the size of lithium batteries.
4. Energy aspect: Vanadium batteries require a pump to maintain the flow of electrolyte during operation, resulting in energy loss and lower energy conversion efficiency. The efficiency of vanadium battery systems is only 70%-75% of that of lithium batteries.
5. Operating Costs: Initial installation costs are high, twice that of lithium batteries, with total project investment costs ranging from 3.8 to 6.0 yuan/Wh. However, this can be reduced with economies of scale. If calculated over the entire lifespan, assuming a cycle life of 12,000 cycles, the cost of vanadium batteries is 0.72 yuan/kWh, lower than the 0.80 yuan/kWh cost of lithium battery energy storage. Since vanadium only undergoes a valence state change in the electrolyte, it can be almost completely recycled. Considering recycling, the total lifespan cost of vanadium batteries is only 0.48 yuan/kWh.
6. Energy Security: Lithium mines are mainly distributed in South America, Australia, and other countries and regions, with China accounting for only 7% of the reserves, posing an energy crisis. However, as of the end of 2021, China had the world's largest vanadium reserves, accounting for approximately 39%, and its production accounted for 68% of the global total.
Can vanadium batteries replace lithium batteries?
Vanadium batteries hold promise for partially replacing lithium batteries in the energy storage field. Vanadium batteries offer significant safety improvements and are easily scalable, while lithium batteries face greater risks during capacity expansion. Vanadium batteries exhibit extremely low capacity loss during charging and discharging, resulting in outstanding cost-effectiveness throughout their entire lifecycle, making them suitable for energy storage, particularly for large-scale energy storage in renewable energy sources such as photovoltaics and wind power. However, vanadium batteries also face a strong competitor in the energy storage sector: sodium-ion batteries, which are currently experiencing faster commercialization.
