The world's largest lithium battery energy storage power station caught fire, a brief analysis of the safety of lithium batteries and vanadium redox flow batteries

The world's largest lithium battery energy storage power station caught fire, a brief analysis of the safety of lithium batteries and vanadium redox flow batteries

On May 15, a fire broke out at the Gateway 250MWh lithium battery energy storage power station in Otay Mesa, San Diego, California, USA. The energy storage project is located in an industrial park in the 600 block of Camino de la Fuente. So far, the fire has reignited twice and continued to burn for six days, and the fire has not yet been fully controlled.

Typically, buildings where lithium-ion batteries are installed are equipped with fire detection systems that spray chemicals onto the batteries to extinguish possible flames. But if this method fails, large amounts of water will be needed to control the flames and keep the battery cool. At the height of the fire, standpipes from the building's sprinkler system sprayed 350 gallons of water per minute.

At present, fire officials are still unable to accurately estimate how long the fire will last. In interviews with local media, fire officials said it may take several weeks to extinguish the fire. One reason battery storage fires are difficult to extinguish is because the materials used in lithium-ion batteries generate oxygen on their own. Although water-based fire extinguishing agents can cool an overheated battery, they will not completely extinguish the fire.

A brief analysis of the safety of vanadium redox flow batteries:

Compared with lithium-ion batteries, vanadium flow batteries are safer. The electrolyte of the vanadium redox flow battery is an acidic aqueous solution of vanadium ions. It operates at normal temperature and pressure, has no risk of thermal runaway, and is inherently safe. According to empirical results, under theoretical 100% SOC, even if the positive and negative electrolytes are directly mixed and the temperature rises from 32°C to 70°C, the vanadium redox flow battery system will not cause risks such as combustion or fire.

On the other hand, from the operating principle, the electrolyte of the flow battery is stored in a tank outside the battery stack. During charging and discharging, the positive and negative electrolytes will enter the battery stack from the circulation pump respectively, and an oxidation reaction will occur. After the reaction is completed, the electrolyte will be pumped back into the tank again, and the cycle will repeat until the reaction is complete. Since the electrochemical reaction and the entire charge and discharge process occur under water-based conditions, there is no risk of combustion and explosion, ensuring absolute safety.

Flow batteries will not produce harmful substances during operation and will not cause harm to people. Its electrolyte can be reused through recycling and processing, complying with environmental protection requirements.

In addition, according to the technical parameters of some flow batteries that have been put into use, their service life is as long as 25 years, and they can charge and discharge more than 25,000 times at 100% DOD (100% deep discharge).

In terms of usage scenarios, flow batteries are a technology that meets the needs of large-scale long-term energy storage. It is not only safe, but also has the advantages of flexible site selection and easy deployment. It is not affected by the geographical environment and can fully meet the multi-scenario needs of end users such as energy storage system integrators, wind and photovoltaic power stations, data centers, and 5G base stations.