Sep 11, 2019 Pageview：25
Vanadium flow batteries after 20 years of development, is a kind of more mature energy storage technology.Its application direction is primarily a new energy of electric field and grid MWh level large scale energy storage station.And mainly do mobile power supply lithium battery compared to their relationship like spoons and Turner, no alternative space to each other.All vanadium flow batteries main rival, is a large-scale energy storage technology such as hydraulic energy storage, compressed air energy storage, flow batteries, and other system.
Vanadium flow batteries relative there are three main advantages of lithium battery:
A, convenient scale.A system can do your home freezer so big, also can do your home village substation, power is enough you home one day to a year, think how to design how to design.
Second, long service life.You can also use half a century.
Three, security is good.In the face of lithium ion batteries taboo of large current and charge discharge without any pressure, and do not fire explosion.
Problem mainly is a:
The energy density is low.Don't try to use on your phone, the electric car also didn't what to expect.
Vanadium flow batteries after 20 years of development, is a kind of more mature energy storage technology.Its application direction is primarily a new energy of electric field and grid MWh level large scale energy storage station.And mainly do mobile power compared to lithium batteries, their relationship is like spoons and Turner, no alternative space to each other.All vanadium flow batteries's main rival, is a large-scale energy storage technology such as hydraulic energy storage, compressed air energy storage, flow batteries, and other system.
The mountains there is a village called litsun, mountain road far from electricity.A few years ago to get coverage, match the generator, but diesel is still very well.After the sun goes down, the yellow light has become a luxury.
Year end will come, with cold north wind, in the town dried electrician dog hi li riding a tricycle appeared on the winding mountain road, the car bucket pulled a few big shiny after the blackboard.
"Well, son of a bitch boss yellow crane with solar energy, owed $3.5, with his sister-in-law and ran away.We have no way, with photovoltaic panels on wages.I heard this thing call in the sun, not burning oil and water.I come back into two pieces, the children have a book to read in the evening, cui flower also got a needle and thread."
Lee dog hi of photovoltaic panels, however, like leonardo flashlights, night without the sun
Make up a story to illustrate the plight of the new energy industry.Lee dog problems hi, wind power engineers in the face of the same.
To some extent, our common grid, arguably the world's largest, the highest energy machine, and the magic is this machine must be kept in every moment of energy balance, the roar of pithead power plant steam turbine output, and the distance to the north China plain consumption down lights.This is a long walking a tightrope.There is no doubt that we have a plenty of control means to keep balance, but also be a natural and man-made, always miss example is the increase in the near 3 years power outages and 08 snow disaster in south China power grid.
New energy grid brings power engineers more headache problem: the weather.Users tend to demand is difficult enough, this is again a to see a miracle of god's face...This day not lead (╯ ￣ Д ￣) ╯ ┻ ━ ┻ 2012 jilin province to abandon the wind rate of 32%, which is a third of the electricity generated is lost in the wind.In addition to the cause of the local consumption ability is limited, for the problem of control is also a reason.The volatility of wind and photovoltaic (pv) in a short period of time is very serious, it is difficult to synchronous with power grid, commonly known as "waste electricity", if direct grid will lead to the entire power system instability.
Above the crux of the problem is that did not exist in our grid of an energy storage mechanism, like leonardo flashlight without batteries.If we can to achieve cast high low suck, jargon peak shaving, abandon the wind and control problems are solved.Currently, only to adapt to the demand by adjust the output of the generator.However, generating units are usually under the rated power at the highest efficiency, frequent change of output inevitably leads to lower efficiency.So for the existing power system, energy storage technology is also has the significance of energy conservation and emissions reduction.
Load sketch, pink curve for wind farm output, brown curve for electricity demand.Energy storage systems under the red area of energy absorption and release in green area.If there is no energy storage system, this part of the electric power is wasted.
At present more mature energy storage technology mainly include: hydraulic energy storage, compressed air energy storage, flow batteries, lead-acid batteries, flywheel energy storage, super capacitor, and so on.As shown, depending on the energy storage size, each technology has its different scope.
The scale of the power of energy storage and energy storage time, total vanadium flow batteries can be dozens of kW to dozens of MW of power, energy storage time for a few hours to a few days.
The energy efficiency of each energy storage system, the whole efficiency of vanadium flow battery (VRB) about 70-80%, and hydraulic energy storage (PHS), compressed air energy storage (CAES), slightly lower than lithium batteries and supercapacitors.
The development of the energy storage technology.The most mature technology today the lowest cost of energy storage technology is hydraulic energy storage (PHS), however, this technique is limited by geographical condition of wide application.All vanadium flow battery (VRB) mature poison below average.Relative to other technologies, flow batteries applicability is wide and its cost is moderate.At present the main application of peak shaving is wind power, photovoltaic electric field.The world has more than 20 kWh - level MWh flow battery business demonstration projects, dalian is one of the biggest melt the energy storage of longyuan wind power projects.
Dalian integrating branch energy storage is responsible for a whole vanadium flow batteries, white cylinder as the energy storage tank, the middle row of joint management of square pile by electricity.
When the size of the energy storage system to achieve a certain degree, can implement support for the power grid.Distributed in the grid energy storage station according to each link of each part of the input/output fluctuation in peak shaving, can smooth transmission load of the system, and minimize the possibility of overload, and increase the efficiency and quality of power supply;In off-grid system like islands, remote areas, and even parts of the city buildings, energy storage system and the combination of new energy can bring on clean energy solutions, reduce the wastage of the long-distance transmission.Future energy storage station would like your home village of substation are common.
Don't know much about the industry, dare not to use sovereignty.Flow cell as a kind of energy storage technology, largely dependent on the development of new energy industry, is one.In the face of the current situation of the drop in oil prices, many have horse photovoltaic, wind power project faces the challenge of cost, and a high-performance energy storage system can greatly improve the economic benefit of the electric field.With the expansion of energy storage systems, energy storage technology as a new control method is introduced into power system, have the opportunity to dramatically change the face of the power grid.Dalian this year won the second prize of national scientific and technological progress of professor zhang hm by physical and chemical, can reflect the policy from one side to the technology of porcelain.However, on the other hand, in this small profits in the industry of power equipment, and fluid flow battery, after all, unlike electronic equipment power supply,Power batteryIndustries have high added value products and the free market, it is difficult to separate a profit, its development more dependent on the policy.At present domestic do better unit is mainly and dalian dalian chemical energy storage, technology accumulation is deep.Recently some vanadium ore companies are doing related projects, comparative advantage of raw materials.
Second, the technology
Since 1985, when Margaret spellings kyllas - Kazacos demo success the first prototype, the development of vanadium flow batteries have more than 30 years.Vanadium flow batteries belong to stream flow batteries, the use of vanadium ion of sulfuric acid solution as a storage medium for electricity.As a transition metal vanadium valence state is very abundant (jing) rich (fen), 2, 3, 4, 5 valence ions have good solubility in water, and the colour is also very good.Vanadium ion between 2 and 5 price is 1.25 V potential difference, this gives the vanadium of themselves and their ability of the battery.
This goods structure, including most OF the other flow battery probably all that long, OF coolie have illustrated in your answer.
System consists of a pile, two energy storage tank, and matching of pump and pipeline.Electrolyte is energy storage jar at ordinary times, when charging and discharging pump pumping of pile reaction.Pile is the basic structure of a sandwich, followed by the positive set fluid, the anode carbon felt, diaphragm, the cathode carbon felt, anode fluid.Is the cathode electrolyte in the pore of carbon felt.Charge and discharge, the vanadium ion in the electrolyte on the surface of carbon felt the gain, and hydrogen ions through the ionic exchange membrane to maintain neutral.The sandwich can be arbitrary superposition to improve the electric voltage.
Practical application, the energy storage tank, electric reactor, flow pump, the BMS and inverter can be integrated in a container, automated operation, or standing on the great plains or wind farms in the village or a hellhole silently station in your area.
The characteristics of vanadium flow batteries brought the following advantages:
1. Convenient scale
For an energy storage system, the most important performance is power and power.Vanadium battery, in general, can withstand the power of and electrode is directly proportional to the area, and is directly proportional to the size of the pile.And how much power and electrolytic liquid is directly proportional to the product, and is directly proportional to the size of the storage tank.In other words, no matter how projects are proposed on the performance of energy storage system, siege lion students can easily add a pleasant accordingly design;Even met wonderful work to party a constantly changing, as well as the original plan on the simple increase or decrease of the energy storage tank and the number of pile to adjust.
Don't look down upon this, such advantages of lithium ion battery is very envy.Lithium ion battery energy storage material made the electrode coating on the surface set fluid, its process and performance is played by chemists to design good before, it is difficult to adjust according to the specific project.So, want to improve your power?Increasing the electrode area.Want to improve your energy?Increasing the electrode area.As a result, the lithium ion battery power is directly related to the density of engineering on this call coupling.The lion's shoes was very hate this kind of thing.
Architecture more important advantage of vanadium battery extensibility.A vanadium battery and can save electricity once a vanadium battery can save ten thousand KWH, structure and control method is essentially the same, but also because of the large scale cost reduced.Energy storage as long as the electrolyte stirring a stirring, mixing can ensure the consistency of the depth of the charge and discharge.And if you want to do a same size of lithium battery system, only a simple pile of cell number, at the same time need and its complex battery management system (BMS) to manage each section temperature and depth of charge (SOC) of battery, otherwise been put overheating will cause the battery charge scrap or even dangerous.A tesla MWh of level with thousands of pieces of batteries battery pack is very crazy, all by panasonic 18650 excellent consistency and powerful BMS didn't hold up.If do 100 times again on this foundation, the complexity of the system will greatly increase the cost.
2. Long service life
On the market of lithium ion battery life is about 1000-5000.Lithium ion battery energy storage principle of the main is lithium ion on the solid electrode embedding and embedded.Electrode materials in lithium ion repeatedly thrusting (mistakenly) under stress change, eventually lead to decline over time.Vanadium battery charging and discharging mechanism is, however, the change of the valence, this is a completely reversible process, the number of cycle test in the lab is ten thousand meter for the unit.Considering the system in other parts of life, can use half a century is completely can do it.In your home in the substation, it saves a lot of maintenance costs.
Even if compared with those of other flow battery technology of vanadium battery endurance is easing the bit in the house.Flow battery pile is between the cathode is separated by a layer of ion exchange membrane, avoid is the cathode electrolyte mixed cross contamination.Now, however, even the best performance of Nafion membrane can be tight, over time there will always be part of the ion penetration to the opposite.For asymmetric flow battery, the positive ions on the cathode can't participate in the electrode reaction, resulting in slow decline until eventually capacity down half of their original cost.For vanadium battery, however, is the cathode is negative electrolyte composition is the same, whatever you zha penetration, anyway I re-charge your charge back ╮ (╯ del ╰) ╭
Need long time storage, electricity in the heap is to prevent the negative electrolyte electrolyte can be emptying contact, therefore, the vanadium battery self-discharge rate is low, the storage time can be in a few hours to a few days.
3. The security
Above mentioned,Lithium battery packComplex battery management system is needed to prevent overcharge discharge and overheating, overcharge and large current will cause the electrode material failure scrapped, lithium battery expansion leakage analysis even short circuit.Carbon materials and carbonate in the battery electrolyte is flammable, such as leakage is easy to cause fire explosion.
However in vanadium battery using vanadium ion in aqueous solution is reversible chemical price change, performance does not depend on the electrode structure, so even if the abuse suffered by the current is also very acutely resistant (false).The same charge also will only lead to the electrolysis of water, as long as timely discharge pressure relief of hydrogen, there is no problem.As for a fire...Do you think aqueous solution will be on fire?╮ (╯ _ ╰) ╭
If there's any security concerns, it is the acidic electrolyte.Vanadium battery electrolyte containing relatively concentrated sulfuric acid (2-3 mol/L) to increase the solubility of pentavalent vanadium and water oxygen evolution potential, while pentavalent vanadium have certain toxicity.Yet comprehensive whole life cycle, environmental friendliness of vanadium battery relatively lead-acid battery still has a considerable advantage.
The armour is the soft rib.Vanadium battery weakness lies in its low energy density, only 15 to 40 wh/L, even worse than lead-acid batteries, lead to equipment volume weight big, difficult to applied to the mobile power supply.Molecular weight is bigger, vanadium salt itself in water solubility is also limited.The electrolyte on the market often use 1.5 2 mol/L vanadium solution, the current world record is 3 mol/L.Project is a master in hand trying to refresh this number, very ashamed, this tiny work was done at present.
After 30 years of development, the performance of vanadium battery has been close to the ceiling, academic circles are also trying to exploit other electrochemical system.Which are comparatively mature technology commercialization with sodium - much sulfur flow batteries, zinc - bromine half flow battery (zinc negative extremely metal electrode), drainage flow battery energy density of the record holder for zinc - iodine flow battery (any zinc - polyiodide, 167 wh/L), and organic system record holder in the energy density of lithium - sulfur semi-solid flow batteries (lithium - sulfursemi solid).The other system is not spread.
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