Vanadium battery is one of the excellent green environmental protection batteries with strong development momentum (it does not produce harmful substances during its manufacture, use and disposal). It has a special battery structure, which can be deeply discharged at high current density; fast charging; high specific energy The price is low; the application fields are very broad: such as backup power supply for buildings, airports, and program-controlled exchange stations; it can be used as a supporting energy storage device for clean power generation systems such as solar energy; it can provide electricity for submarines, ocean-going ships, and power grid peak regulation.
The cost of vanadium battery is similar to that of lead-acid battery, and it can also prepare megawatt battery pack, which can provide electricity with high power for a long time. Therefore, vanadium battery has the incomparable cost-effective advantage of lithium-ion battery and nickel-hydrogen battery in the field of large-scale energy storage. Vanadium batteries have simple production process, economical price and excellent electrical performance. Compared with fuel cells that are complex and expensive to manufacture, they are more competitive in terms of large-scale energy storage and application prospects of electric vehicle power sources.
Advantages of vanadium batteries
Compared with other chemical power sources, vanadium batteries have obvious advantages. The main advantages are as follows:
1. High power: By increasing the number of monolithic cells and the electrode area, the power of vanadium batteries can be increased. At present, the power of vanadium batteries in commercial demonstration operation in the United States has reached 6 MW.
2. Large capacity: By arbitrarily increasing the volume of the electrolyte, the power of the vanadium battery can be increased arbitrarily, up to more than GWh; by increasing the concentration of the electrolyte, the power of the vanadium battery can be doubled.
3. High efficiency: due to the high catalytic activity of the vanadium battery, and the positive and negative active materials are stored in the positive and negative electrolyte storage tanks respectively, the self-discharge consumption of the positive and negative active materials is avoided, and the charge and discharge energy of the vanadium battery is reduced. The conversion efficiency is as high as 75%, much higher than 45% of lead-acid batteries.
4. Long service life: Since the positive and negative active materials of vanadium batteries only exist in the positive and negative electrolytes, respectively, there is no phase change common to other batteries during charging and discharging, which can be deeply discharged without damaging the battery, and the battery has a long service life. . At present, the vanadium battery module with the longest running time in the commercial demonstration of VRB PowerSystems in Canada has been in normal operation for more than 9 years, with a charge-discharge cycle life of more than 18,000 times, much higher than the 1,000 times of stationary lead-acid batteries.
5. Fast response speed: The vanadium battery stack can be started instantly when it is full of electrolyte. It only takes 0.02 seconds to switch between the charge and discharge states during operation, and the response speed is 1 millisecond.
6. Instant charging: by changing the electrolyte, the vanadium battery can be charged instantly.
7. High safety: Vanadium batteries have no potential explosion or fire hazard, even if the positive and negative electrolytes are mixed, there is no danger, but the temperature of the electrolyte increases slightly.
8. Low cost: In addition to ion membranes, vanadium battery components are mostly cheap carbon materials and engineering plastics, which are rich in material sources and easy to recycle. No precious metals are needed as electrode catalysts, and the cost is low.
9. Vanadium battery has a large degree of freedom in site selection, can be fully automatic closed operation, no pollution, simple maintenance and low operating cost.
Practical application advantages
1. As the place where the reaction occurs, the stack is separated from the storage tank for storing the electrolyte, which fundamentally overcomes the self-discharge phenomenon of traditional batteries. The power only depends on the size of the stack, and the capacity only depends on the electrolyte storage and concentration. The design is very flexible; when the power is constant, to increase the energy storage capacity, it is only necessary to increase the volume of the electrolyte storage tank or increase the volume or concentration of the electrolyte. Yes, without changing the size of the stack; the purpose of "instant charging" can be achieved by replacing or adding the electrolyte in the state of charge. It can be used to build kilowatt-level to 100-megawatt energy storage power stations, with strong adaptability.
Second, the charging and discharging performance is good, high-power charging and discharging can be carried out, and floating charge and deep discharge can also be allowed. For lead-acid batteries, the larger the discharge current, the shorter the battery life; the deeper the discharge depth, the shorter the battery life. Even if the depth of discharge of vanadium battery reaches 100%, it will not affect the battery. Moreover, vanadium batteries are not prone to short circuits, which avoids safety issues such as explosions caused by short circuits.
3. The number of charging and discharging is extremely large, and the theoretical life is countless times. The charge-discharge time ratio is 1:1, while the lead-acid battery is 4:1. Moreover, the vanadium battery has a fast charging and discharging switching response speed of less than 20 milliseconds, which is very conducive to balanced power supply.
Fourth, the energy efficiency is high, the DC to DC energy efficiency can reach more than 80%, while the lead-acid battery is only about 60%. The state of each unit cell in the vanadium battery pack is basically the same, and the maintenance is simple and convenient.
5. The site selection has a large degree of freedom and occupies a small area. The system can be fully automatic closed operation, and there will be no acid mist and no acid corrosion. The electrolyte can be reused, no emissions, simple maintenance and low operating costs. It is a green energy storage technology. Therefore, for renewable energy generation, vanadium batteries are ideal substitutes for lead-acid batteries.