Reasons for using flow batteries

Reasons for using flow batteries

If we use wind and solar power generation systems that need to be repeatedly turned on and off to operate the high-voltage transmission line network, we need highly reliable and well-designed batteries. As a 30-year-old battery technology, flow batteries are most suitable for such applications. (Note: Flow battery is a new electrochemical energy storage technology. It separates the positive and negative electrolytes and circulates a high-performance storage battery. According to different electrolytes, flow batteries can be divided into: full Vanadium flow batteries, zinc bromine flow batteries, sodium polysulfide/bromine flow batteries, zinc/nickel flow batteries, etc.) Flow batteries use two liquid electrolytes, which react when they are pumped through the galvanic stack , Can replace the solid-state electrodes currently used in conventional batteries. Essentially, the battery can be broken down into a stack of galvanic cells and two large liquid electrolyte pools. When the electrolyte flows through the porous membrane of each battery, and ions and electrons flow back and forth, a charge and discharge cycle occurs in the battery. Charging requires adding fresh liquid electrolyte to increase energy storage capacity. Therefore, in order to improve the charging time and charging efficiency, a slightly larger tank may be required. Such batteries have been used as backup power sources in factories and mobile phone towers.

Reasons for using flow batteries
flow batteries

Now, manufacturers are looking for venture capital to design and develop batteries for grid systems that will be most suitable for use with wind turbines and solar power generation systems. The U.S. Department of Energy (DOE) has allocated $31 million in Recovery Act funding to initiate five utility-level projects. (Transmission lines) The cost of system network storage applications is crucial. This is the advantage of flow batteries that can complete the work at the lowest cost and complexity. Research on energy storage technology shows that zinc-bromide batteries can currently store less than $450 per kilowatt hour (kw·h) of electrical energy during operation, which is 1/3 of lithium batteries and 3/4 of sodium-sulfur batteries.

Because of their inherent flow structure, these batteries are relatively safer and more cost-effective. In addition, with flow batteries, one megawatt hour (MW·h) of electrical energy can be stored in the electrolyte tank. In an article recently published by IEEE Spectrum, it was revealed that a zinc-bromide battery (ZBB) that can be transported on a trailer has demonstrated a storage capacity of close to 2.8 Mw·h. Such batteries, when connected to the utility grid, are most suitable for reducing peak loads. Flow battery technology is fully mature, but it still faces challenges in adapting to the scale of public utilities and doing complete system integration. The latter includes high-efficiency power electronics technology and rapid response control.