Behind the largest flow battery on grid-what’s the development trend of vanadium batteries

On October 30, 2022, the world’s largest flow battery peak shaving power station with the largest power and capacity finished on grid in Dalian, Liaoning, China. This is a milestone in the field of liquid flow battery. Under the background of dual carbon, all vanadium flow battery is quietly rising in the large-scale electricity storage application scenario.

A lot of capital is added to the layout of all vanadium flow battery

The data shows that by the end of 2021, the cumulative installed capacity of power storage projects that have been put into operation around the world is 209.4GW. The cumulative installed capacity of new energy storage projects is 25.4GW, which is second only to pumped storage projects, with a year-on-year growth of 67.7%. Among them, lithium-ion batteries occupy an absolute dominant position with a market share of more than 90%.

But this pattern is changing. In June this year, the China Energy Administration issued a document: the medium and large electrochemical energy storage power stations should not use ternary lithium batteries, sodium sulfur batteries, and should not use power batteries for cascade utilization.

On the other hand, the explosion of the energy storage market on the new energy side, the continued hot sales of new energy vehicles, the imbalance between supply and demand in the global industrial chain, the serious shortage of lithium battery capacity and other multiple factors combined to make the price of lithium carbonate, the raw material of lithium batteries, rise again and again.

On October 26, the average price of battery grade lithium carbonate rose above 550000 RMB/ton, setting a new record. Due to the potential safety hazards of lithium batteries and the rising prices of raw materials, many capitals have increased their deployment of all vanadium flow batteries as another technical route in the field of electrochemical energy storage.

Long term energy storage is the key reason why the market values all vanadium flow battery

Under the background that renewable energy gradually occupies the dominant position in power generation, how to stabilize the power balance between the power generation end and the power receiving end of the power system, and establish a highly reliable and flexible security mechanism, long term energy storage with charging and discharging time exceeding 4 hours is the preferred solution.

In the technical route of long-term energy storage, the advantages of liquid flow battery as one of the important trends are obvious. In the past few years, the technical route mainly focuses on all vanadium liquid flow battery. Long term energy storage is also the key reason why the market values all vanadium flow battery. 

In recent months, A-share vanadium battery concept stocks have continued to be hot, and Pangang Group Vanadium Titanium, WTECL and other listed companies have increased their layout or cross-border entry into the field of all vanadium liquid battery industry through different ways, such as renaming, regular increase of capital raising, investment and construction of new capacity, purchase of vanadium mineral resources, signing of strategic cooperation agreements, etc.

In September 2022, LB Group, a leader in titanium dioxide in China, said that it was currently conducting vanadium battery technology research and development. In the future, the company will actively promote the industrialization of vanadium battery materials according to the vanadium battery market.

Pangang Group Steel Vanadium was also renamed “Pangang Group Vanadium Titanium” in September. A fixed increase plan of 2.28 billion RMB has also been put forward. The proposed investment includes upgrading and reconstruction of vanadium pentoxide, industrial preparation and application research and development of vanadium battery electrolyte, and other projects involving the upstream and downstream of the vanadium battery industry chain.

In the next five years, all vanadium flow battery will usher in a round of explosion

On September 20, 2022, the first GWh all vanadium liquid flow energy storage power station in China – 250MW/1000MWh all vanadium liquid flow battery energy storage supporting 1GW marketable photovoltaic project in Chabuchar County, Xinjiang, China was started, and it is planned to be on grid by the end of 2023.

In the same month, the vanadium flow battery energy storage system also ushered in the first GWh level centralized procurement. CNNP recently announced the largest centralized procurement of energy storage system this year, with a total procurement scale of 5.5GWh, including 1GWh all vanadium flow battery energy storage system.

On October 30, the 100 trillion level liquid flow battery energy storage and peak shaving power station in Dalian, China, was connected to the grid for power generation. This power station is the first large-scale chemical energy storage demonstration project approved by the China Energy Administration, which applies all vanadium liquid flow battery energy storage technologies.

In March 2022, China released the implementation plan for the development of new energy storage, which clearly proposed that the 100 megawatt liquid flow battery technology should be included in one of the key directions for tackling new energy storage core technology and equipment. It can be predicted that in the next 5 years, all vanadium flow battery will usher in a round of explosion.

How good are vanadium flow batteries

All vanadium redox flow battery is a kind of redox battery with vanadium as the active material and circulating liquid. It is characterized by the use of the same element vanadium in the positive and negative electrode redox pair. The electrolyte is renewable in the long-term operation process, effectively avoiding the problem of difficult recovery of battery capacity caused by cross contamination.

On the premise of ensuring the safety of energy storage, the current energy storage technology paths that are expected to be developed and applied on a large scale include all vanadium flow battery, lithium iron phosphate battery and sodium ion battery.

However, vanadium battery is significantly superior to lithium iron phosphate battery and sodium ion battery in terms of safety, capacity expansion, cycle life and full life cycle cost.

Low risk

As the electrolyte matrix of vanadium battery adopts aqueous solution, there is no solid phase reaction during use, so there is no risk of fire, explosion, etc; Moreover, overcharge and overdischarge will only cause electrolysis of water, and safe use can be ensured by timely discharging the generated hydrogen;

The capacity of batteries in other technical routes decreases during storage due to self discharge, while the active substances of positive and negative electrodes of vanadium batteries can be stored in their respective electrolyte tanks, which can avoid self discharge consumption of positive and negative active substances.

Simple capacity expansion

Vanadium battery can be easily applied for modular management. Power and capacity can be designed separately. By connecting multiple groups of energy storage units in parallel to the bus, a larger scale energy storage system can be built, so capacity expansion is simple. Compared with lithium iron phosphate battery, it will not increase additional safety risks in the case of large capacity.

Long service life

At present, the cycle life of commercial vanadium battery can reach more than 16000 times, which is much higher than that of commercial lithium iron phosphate battery for 6000 times. The corresponding service life is more than 20 years, and the reliability has also been verified by examples.

For example, the vanadium battery module with the longest running time in the commercial demonstration of VRB Power Systems in Canada has been in normal operation for more than 9 years, and its charging and discharging cycle life has exceeded 18000 times.

Due to the long cycle life of vanadium battery, the kilowatt hour cost in the whole life cycle is about 0.42~0.53 RMB/kWh, which is lower than 0.56~0.75 RMB/kWh of lithium battery.

Problems to be solved in the commercialization of vanadium batteries in China

Cost

First of all, the initial construction cost of vanadium battery is too high, which leads to weak investment motivation of companies. The data shows that the initial investment cost of vanadium battery energy storage project is about 4-5 RMB/Wh, which is higher than 1.5-2 RMB/Wh of lithium battery project.

As a result, most vanadium battery projects are demonstration projects promoted by local governments, and only a few are self built projects by companies. In the future, the government still needs to promote the development of an effective price compensation mechanism and long term energy storage industry policy.

Development efforts

In China, although vanadium ore reserves are rich, as China’s main vanadium production comes from vanadium slag in the process of vanadium titanium magnetite steelmaking, if the development effort is less than expected, the large-scale application of vanadium batteries will drive up the vanadium price and further raise the cost of electrolyte.

Therefore, allowing the corresponding steel companies to expand their production capacity to increase the sources of vanadium resources, or introducing policies to support the development of vanadium resources, and increasing the development of vanadium resources in China should become the focus of future policies.

Technology

At present, the development of vanadium battery industry chain is still at an early stage. There are few companies with vanadium battery technology, and the industry development still breaks through technical barriers.

For example, the energy density of all vanadium flow battery is low, only 12-40Wh/kg, which is lower than 80-300Wh/kg of lithium battery. Vanadium battery needs a pump to maintain the flow of electrolyte, so its loss is large. The energy conversion efficiency is 70-75%, which is 90% lower than that of lithium battery.

All vanadium redox flow battery has strict requirements on environmental temperature. Once the working environment is higher than 45 ℃, sediment will be precipitated in the positive solution to block the flow passage, which will eventually affect the work or even scrap. However, as long as the electrolyte reacts, it is exothermic and easily exceeds the limit temperature.

The ion exchange membrane is used to separate the positive and negative electrodes of the liquid flow battery to prevent cross contamination caused by the mixing of positive and negative electrolyte.

However, there are still some unsolved problems in this technology, which makes cross contamination of positive and negative electrolyte and corrosion of positive electrode materials occur from time to time. In many cases, the maintenance of all vanadium liquid flow battery requires regular manual operation by professionals.

Based on the current shortcomings of all vanadium flow battery, many efforts and attempts are bound to be made in the large-scale application of vanadium battery in the energy storage industry in the future.