Detailed Explanation Of The Vanadium Redox Flow Battery Industry Chain
- Technical principle of vanadium redox flow battery
- The industrial chain of vanadium redox flow battery
- Future outlook
A flow battery is a battery technology in which active substances exist in a liquid electrolyte. The electrolyte is outside the stack and flows through the stack driven by a circulating pump to convert chemical energy into electrical energy.
Internationally, there are mainly four technical routes for flow batteries: vanadium flow batteries, zinc-bromine batteries, iron-chromium batteries, and sodium-bromine polysulfide batteries.
Among them, the current industrial chain construction and technology maturity of vanadium redox flow battery are relatively high. Different from the logic of lithium batteries in energy storage applications, flow batteries are mainly due to their scalability, which are used for long term energy storage, so in power systems there is a certain room for development.
Technical principle of vanadium redox flow battery
The vanadium flow battery is currently the most mature flow battery technology. The vanadium flow battery is the only battery with a single active material in the flow battery. It uses the change in the valence of vanadium ions to realize the conversion between electrical energy and chemical energy.
The vanadium redox flow battery system consists of a power unit (stack), an energy unit (electrolyte and electrolyte storage tank), an electrolyte delivery unit (pipelines, valves, pumps, sensors and other auxiliary components) and a battery management system. Among them, the stack is composed of ion exchange membranes, electrodes, bipolar plates, electrode frames, seals and other materials.
The vanadium redox flow battery uses vanadium ion solutions with different valence states as the active materials of the positive and negative electrodes, and stores them in the electrolyte storage tanks of the positive and negative electrodes respectively.
When charging and discharging, under the action of the pump, the electrolyte circulates through the positive and negative chambers of the battery from the electrolyte storage tank, and oxidation and reduction reactions occur on the electrode surface to realize the charging and discharging of the battery.
The industrial chain of vanadium redox flow battery
The main raw materials required for its upstream are vanadium-uranium ore, phosphorus-vanadium ore, stone coal-vanadium ore, and vanadium-iron-magnetite.
The upstream mainly involves the mining and smelting of vanadium resources. my country’s vanadium resources mainly exist in the form of vanadium-titanium magnetite and vanadium-containing stone coal. Among them, the grade of vanadium in stone coal mines is low and the pollution in the process of vanadium extraction is relatively serious.
The overall production cost is higher than that of steel slag. Most vanadium products come from vanadium-rich steel slag obtained from vanadium-titanium magnetite through iron and steel smelting.
China’s vanadium-titanium magnetite reserves are mainly distributed in Panzhihua, Sichuan, Xichang and Chengde, Hebei. Among them, the Sichuan Panxi region has proven vanadium-titanium magnetite reserves of more than 10 billion tons, which is the world’s largest vanadium resource and vanadium-based product production area. The proven reserves of vanadium-titanium magnetite in Chengde, Hebei are more than 8 billion tons.
Midstream manufacturing integration
Its energy unit includes electrolyte and storage tank. Its power unit includes ion-conducting membranes, bipolar plates, and electrodes. Its supporting systems include pump valves, pipelines, and battery management system.
At this stage, vanadium redox flow battery manufacturers have a relatively high degree of integration, and the industrial chain ecology has initially been established. Overall, the current vanadium redox flow battery energy storage is still in the early stage of commercial operation.
The industry leader Rongke Energy Storage was established in 2008. After decades of development, the company has the ability to develop the entire industry chain from front-end R&D to back-end project operation, and is deeply involved in all links of the vanadium redox flow battery industry chain.
Since the vanadium redox flow battery technology has not been finalized in the early stage, and the project volume is relatively small, the industry presents the characteristics of non-standardization and customization, and the industrial chain ecology is mainly dominated by integrated leading manufacturers.
The electrolyte is the core material in the vanadium redox flow battery, which directly affects the performance and cost of the energy unit. As a storage medium for electrical energy, the volume and concentration of the electrolyte determine the maximum energy that can be stored in the vanadium redox flow battery energy storage system.
In theory, 5.6 kg of vanadium pentoxide is required to store 1 kWh of electrical energy, but the actual utilization rate of the electrolyte is currently only about 70% can be achieved (that is, about 8kg of vanadium pentoxide is needed to store 1kWh of electric energy).
Therefore, improving the utilization rate of the electrolyte is an important way to reduce the cost of vanadium redox flow batteries. In addition, factors such as the purity of the electrolyte (generally more than 99.9%), stability, and applicable temperature range will also have a greater impact on the operating efficiency and life of the vanadium redox flow battery.
The ability to develop and prepare electrolytes is one of the most important core competitiveness of vanadium redox flow battery manufacturers. On the one hand, the electrolyte requires high control over impurities and valence states in the preparation process.
How to achieve high purity at low cost requires long-term process accumulation. Currently, the preparation methods of vanadium electrolyte mainly include physical dissolution method, chemical reduction method There are three types of methods and electrolytic methods, among which electrolytic methods are mainly used for large-scale preparation.
On the other hand, in order to improve the energy density, electrochemical activity and thermal stability of the electrolyte, it is usually necessary to add certain additives (including mixed acids, inorganic salts, organic substances and other systems) to the electrolyte. Deep research and development accumulation is required.
Therefore, on the whole, the development and preparation of vanadium redox flow battery electrolyte has relatively high barriers. At present, only a few enterprises in China, such as Dalian Rongke Energy Storage Group Co., Ltd. and Hegang, have mass production capacity.
The downstream of vanadium redox flow battery is mainly used in wind/solar/traditional power stations, power grid companies, and large-scale industries and commerce.
Considering that the initial investment cost of vanadium redox flow battery itself is relatively high, it is expected that the investment in vanadium redox flow battery energy storage projects will be mainly dominated by large power generation companies or power grid companies in the short term.
At present, large power groups such as Datang, State Power Investment Corporation, and China Guangdong Nuclear Power Group have launched the construction of 100 MWh-level vanadium redox flow battery energy storage projects. Huadian, State Grid Jiangsu, etc. are also trying demonstration projects.
After the verification of the previous projects, vanadium redox flow batteries are expected to become a type of energy storage form that large power groups will focus on in the future.
vanadium redox flow battery energy storage also has broad development space in large-scale industrial and commercial user-side scenarios. Whether it is from the perspective of ensuring power supply stability or reducing comprehensive electricity costs, industrial and commercial users have an urgent need to configure energy storage.
At the same time, compared with Chinese power generation side/grid side energy storage market whose profit model has not yet been fully established, the marketization degree of user side energy storage is relatively high, and vanadium redox flow batteries are expected to obtain Favored by some large industrial users.
For example, in 2022, Conch Green Energy, a subsidiary of Conch Group, and Dalian Borong jointly established Anhui Conch Ronghua Energy Storage Technology to carry out related businesses such as system integration of vanadium flow energy storage batteries, investment and construction of energy storage power stations, and electrolyte leasing.
In June 2022, Conch Ronghua issued a bidding announcement for “20MW/120MWh vanadium redox flow battery energy storage system equipment procurement and service”, and the application of vanadium redox flow battery energy storage on the side of large-scale industrial and commercial users continued to accelerate.