Ten measures to promote the development of energy storage batteries

Achieving carbon neutrality at the peak of carbon emissions is a task that China will strive for in the next 40 years. Achieving the double-carbon target must use large-scale renewable energy to generate electricity, and establish a new energy system with a new power system as the main body. Renewable energy is affected by seasons, time, weather, etc., and the fluctuation of power generation will inevitably cause instability; during the period when the power generation of renewable energy cannot be fully consumed, wind and light will be abandoned, and energy will be wasted.

Therefore, in the new power system, from the power generation side, the grid side to the user side, large-scale energy storage must be taken as an important component. This paper puts forward the following ten suggestions for the development of large-scale energy storage batteries in China.

Fully understand the advantages of large-scale energy storage batteries

The battery has high energy conversion efficiency (up to 95%), quick response, easy site selection, short construction period, suitable for various scales, and can complement each other with physical energy storage (up to 75% conversion efficiency), and It has the advantages that physical energy storage cannot replace. Under the goal of carbon neutrality at peak carbon, the importance and superiority of large-scale energy storage batteries will become increasingly prominent.

In addition to building a new type of power system that requires large-scale energy storage batteries, big data centers also require stable and reliable backup power. With the rapid development of large and very large data centers, the scale of their power consumption and backup power is also expanding. In order to save electricity costs, data centers have shown two major development trends: one is that super-large data centers are moving closer to hydroelectric power stations, and the other is that uninterruptible power supplies have shifted to self-built large-scale photovoltaic power stations with gigawatt-hour energy storage power stations, which means Large-scale energy storage batteries must be used, and there is no other way.

In the past 160 years since its birth, batteries have never encountered such high requirements for large scale, long life, and low cost. However, the existing batteries have been modified and adapted, and have performed well in use. In recent years, Advances in energy storage technologies lead to a significant reduction in costs, coupled with the gradual improvement of policies, energy storage has become profitable. Of course, since it is not “tailor-made”, it is inevitable that each has its own shortcomings, so we should pay close attention to improving and improving while giving full play to our advantages. At the same time, the future of developing dedicated new-scale energy storage batteries is limitless.

Performance of the energy storage battery should be properly sorted

The development of large-scale energy storage batteries should adhere to safety first and benefit fundamentally. If the energy storage power station is caught in a fire, everything will be empty. Large-scale energy storage is a commercial activity, which means that benefit is survival and is the foundation of an enterprise. The economic benefits of battery energy storage can be calculated from the YCC index, and the gross profit rate of the energy storage power station to cut peaks and fill valleys = YCC-1.

In order to make the YCC index greater than 1, the initial investment should be as low as possible, and materials with large resource reserves, low price and easy production must be used. At the same time, the energy conversion efficiency must be high, the cycle life must be long, and the charge and discharge depth must be deep. These are the main parameters related to efficiency. Among them, the cycle life and the depth of charge and discharge are contradictory, and the maximum value of the product of the two should be selected for the working conditions during operation. People who are doing basic research on batteries now pay more attention to publishing articles, and pay less attention to the limitation of cost on the application prospects of energy storage batteries, so they should pay attention.

As for specific energy, specific power, environmental friendliness, ease of use, geographical adaptability, etc., they take a back seat because of the characteristics of energy storage used in fixed places. In some occasions, the specific power of the battery is required to be high, which can be solved by the design and production process of this specific battery.

Research and development should pay equal attention to near and far

Historical experience shows that it takes about 20 years for a new battery to be proposed from the principle to a large number of applications. Now that technological advances are accelerating, that time may be shortened, but it’s still 10-15 years away. Therefore, the development of large-scale energy storage batteries must pay equal attention to the near and far fronts, and should not be neglected.

At present, in order to meet the urgent need of carbon peak, we can only select and transform the basically available varieties from the existing battery types. These available batteries are lead-carbon batteries, flow batteries, and lithium-ion batteries. They each have their own advantages and disadvantages. They need to be improved while using them to find the most suitable usage scenarios for each.

From the long-term perspective of carbon neutrality, it is necessary to develop safe, efficient, long-lived and cheap new energy storage batteries based on the characteristics of large-scale energy storage. This is an extremely difficult scientific project that must be planned as a whole and started immediately. Even if research and development starts now, it will only be around 2040 that new types of large-scale energy storage batteries with more comprehensive performance can be truly used.

Further prolong the life of high-safety lead-carbon batteries

Lead-carbon batteries add special conductive porous carbon to the negative electrode of the lead-acid battery, which solves the problem of the particle size of the negative-electrode active material, thus greatly extending the life of the battery, while maintaining high safety and the lowest price of the lead-acid battery. Advantages, it should be the battery of choice for current scale energy storage. In the past two years, a large number of newly built data centers in China basically use this kind of battery as backup power.

Relevant departments supervise the lead-carbon battery industry to eliminate pollution in production and promote the modernization of production equipment and processes, which has greatly promoted my country’s lead-carbon battery technology to enter the forefront of the world. At present, China has built dozens of small and medium-sized lead-carbon battery energy storage power stations, with a maximum capacity of 300 MWh. At the same time, it has also exported 75 MWh frequency modulation power stations to Germany, which have been operating normally for many years.

In 2021, a data center in Texas, the United States negotiated to purchase lead-carbon batteries from my country to build a 4 GWh energy storage power station to provide 24-hour power supply for the data center. Its scale is equivalent to a 1 million kilowatt pumped storage power station. Practice has proved that lead-carbon batteries are suitable for short-term frequency modulation, medium-time peak shaving and valley filling, long-term stable power supply, and are suitable for large, medium and small scales. The only disadvantage is that the low specific energy results in a large footprint.

The life of the lead-carbon battery has reached 5,000 times at 60% DOD. If the initial investment is 1200 yuan/kW, the energy conversion efficiency of the power station is 0.83 (=battery efficiency x PCS efficiency-air conditioning power consumption-line loss=0.90×0.955-0.02- 0.01), the incoming and outgoing electricity prices are 0.3 yuan/kWh and 1.0 yuan/kwh respectively, and the operating cost of the power station outputting 1 kwh is 0.04 yuan, and the calculated YCC is 1.45, that is, the gross profit margin of the energy storage power station is 45%. This does not include the 30% residual value income in the regeneration of waste batteries. It can be seen that its economic benefits are considerable.

At the same time, China’s waste lead-acid batteries have achieved 100% recycling and disposal, and lead is one of the metals with the highest recycling rate. The national major research plan should support a lead-carbon battery, double its cycle life, and develop technologies to reduce lead consumption, further reduce costs, and let lead-carbon batteries play a full role in China’s dual-carbon goals.

Step up support for the development of ferrochrome flow batteries

The biggest advantage of flow batteries is that they can store energy for a long time, and ferrochrome flow batteries are even cheaper. After 20 years of continuous support from the state, the all-vanadium redox flow battery is relatively mature and can be used in production. In the future, its technology will be improved, but it should be an enterprise behavior.

Vanadium, a rare metal, is mainly used in steelmaking. Nowadays, the development of all-vanadium liquid flow power stations is booming. The electrolyte of each kWh requires 8 kg of high-purity V2O5, and the total price is 1,500 yuan, which is 2-3 times higher than other battery cells; Double it. According to the estimated demand for station construction in the past two years, the demand for V2O5 will increase at a rate of 20%-30% per year, and the trend of high prices is difficult to change. Therefore, the weakness of high cost of all-vanadium redox flow batteries will continue to exist. Ferrochromium flow batteries have been neglected for many years and their development has been slow. We should step up support, accelerate its development, and let it have the opportunity to participate in the competition and accept the test of the market.

The scale of lithium-ion battery energy storage should be steadily expanded

Lithium-ion batteries have many advantages, the biggest advantage being high specific energy, but safety is still a big problem. Energy storage power stations in South Korea, the United States, and Australia have caught fire and exploded many times, among which South Korea has the most. On October 15th, a battery in an important data center in South Korea caught fire and lost power, causing the interruption of two major Internet services, paralyzing 32,000 servers, and severely affecting the fields of finance, transportation, and transportation.

The level of safety can be expressed by accident probability. Under the condition that other influencing factors remain unchanged, the accident probability of energy storage power station is proportional to its scale. Therefore, in order to ensure a very low accident probability, the construction scale of energy storage power stations should gradually expand with the improvement of the safety level of the power system, and should not be rushed.

The rapid development of China’s renewable energy power generation, coupled with policy support, has led to the construction of a large number of lithium-ion energy storage power stations, and the scale of each station is also good. At present, the apparent accident probability is far lower than that of South Korea. Except that South Korean batteries mostly use ternary cathodes, the main reason is that the actual utilization rate of my country’s power stations after passing the acceptance inspection is extremely low (no more than 10%). This creates a false impression that the security is not bad, and at the same time, it in turn encourages bold website building and blind expansion of scale. If one day these lithium-ion energy storage power stations are really in operation, the consequences will be unpredictable.

Lithium-ion battery storage is working to improve safety, but it will take time. The established power stations must be put into solid operation. After a long period of trials and tests, problems can be found and reliability improved, and experience can also be accumulated for gradual scale-up.

At present, the accident probability calculation of battery energy storage power plants is still blank. We can learn from the mature methods of nuclear power plants and establish a safety calculation system for battery energy storage power plants. In addition, in order to allow lithium-ion battery energy storage power stations to operate normally and to allow insurance companies to charge reasonable insurance premiums, separate safety insurance can be implemented for energy storage power stations in the power system.

Innovative research and development of special batteries for large-scale energy storage

In order to adapt to the increasing demand for renewable energy, the development of new high-safety and high-efficiency energy storage batteries must be listed as a major national project to seize the commanding heights of new energy storage battery technology and build a battery energy storage powerhouse.

First of all, we must vigorously promote the innovation and technical research of new principles, new systems, and new materials for energy storage batteries. Secondly, in the water system and organic electrolyte system of the battery, the water electrolyte system with high safety should be the main one. Thirdly, inorganic materials can have a higher potential when used as the positive electrode, and should continue to be developed and optimized. Attention should be paid to solving the problem of short lifespan caused by its hydration and dissolution in water.

At the same time, we should attach great importance to the innovation of organic electrode materials, take advantage of its insoluble in water, stable structure, large amount of elements such as carbon, hydrogen, oxygen, nitrogen and sulfur, and easy disposal of waste batteries, design new organic redox compounds, and develop cheap New process of organic synthesis.

Promote the development of various batteries in competition

The energy storage market is huge and the prospects are very broad. Batteries that can accommodate various technical routes have their own abilities. Therefore, it is necessary to create conditions for smooth development and an atmosphere of fair competition for them from various aspects such as policy and public opinion, and there is no need to favor one side.

The chemical substances are rich and colorful, the electrochemical reactions are changeable, and the battery system that can be developed is limitless. Only in the prosperity can it be brilliant. Under the active guidance of development, there will be a variety of general-purpose and characteristic new battery systems.

Don’t easily label old batteries as outdated. On the contrary, it is necessary to pay attention to the technological innovation of old batteries so that they can be effectively used.

Emerging sodium-ion batteries have certain advantages in terms of low temperature and cost, and can continue to be optimized to improve their safety and cycle life. Starting from small and medium-scale energy storage, try to replace lithium-ion batteries. Large-scale energy storage companies can also explore the use of the two batteries together, make full use of the advantages of the two to complement each other, and obtain real comparative data from them to promote subsequent development.

Improve the support mechanism for the whole process of research and development

Relevant departments should organize the cohesive development and one-stop service of the four stages of energy storage battery basic research, practical research, engineering development, and scale demonstration.

The low conversion rate of scientific research achievements is a problem that China has long wanted to solve but has not solved. The reason is that there is no support mechanism for practical research and engineering research, and there are few corresponding institutions between the national, provincial and municipal natural science foundations to support basic research and the national key R&D plan to support scale demonstrations. Especially in the aspect of selectively verifying and screening a large number of new systems and new materials constantly reported in the literature, so as to transform them into practical research on practical batteries, colleges and universities are reluctant to arrange graduate students to complete them because they feel that it is difficult to produce articles. Enterprises Because it feels that there are many uncertain factors and it is too far away from industrialization, it is reluctant to get involved, making it the weakest link that less people care about than engineering development.

To solve this problem, it is necessary for the government to take the lead, enterprises to take the lead, and venture funds to intervene to establish an effective industry-university-research-finance combination mechanism, and to attract specialized agencies that do not worry about funds to make up for and strengthen this weak link. The research institutes of large electric power companies must do their part, intervene in the research and development of new energy storage batteries as soon as possible, actively take over the transformation of innovative achievements in energy storage batteries, and take the lead in improving the maturity of technology. State-owned investment institutions should take the lead in changing concepts, implement risky venture capital, and vigorously support technological innovation and upgrading.

In addition, there is a shortage of talents in the battery industry at present. Poaching people with high salaries in the battery industry is an act of self-interest at the expense of others, which is harmful to the overall development of the industry. The education department should fully estimate and expand the training scale of talents at all levels related to batteries and power stations as soon as possible.

All kinds of battery pollution should be eliminated

Batteries have entered various fields and links of human activities, and will coexist with human beings forever, and the two must get along harmoniously.

Batteries store energy through oxidation-reduction reactions of chemical substances, and all batteries must use chemical substances. The toxicity of various chemical substances varies. If the control is not good, the whole process from raw material production to waste battery disposal may cause different degrees of environmental pollution. Therefore, it is not correct to think that lithium-ion batteries are green, because in addition to the highly toxic cobalt, there are also fluoride and organic substances that are harmful to the human body. However, it can be used in large quantities without polluting the environment. Similarly, it is wrong to say that lead-acid batteries are polluting, because the Ministry of Industry and Information Technology has taken the lead in promoting standardized production a few years ago, focusing on the control of lead-acid pollution to the environment. If we ignore the advancement of technology and management, and still stubbornly insist on the prejudice that lead-acid batteries pollute the environment, it will violate the ideological line of seeking truth from facts.

Pollution from all kinds of batteries must and can be eliminated. The chemicals of large-scale energy storage batteries are used and controlled in a centralized manner. Compared with other scattered small power sources, the pollution control should be done better, and it can be done better. The key lies in the government’s responsibility, continuous management and control, and no slack in the slightest. At the same time, enterprises must abide by the rules, conscientiously implement relevant policies, and must not take advantage of tricks.

Specifically, on the basis of the preliminary rectification of vanadium safety production in the past few years, we must do a good job in the production of new vanadium raw materials required for all-vanadium redox flow batteries, and at the same time pay attention to protecting the environment. Second, we must step up the disposal of waste lithium-ion batteries and green disposal, especially to prevent the solid waste calcium fluoride generated during disposal from landfilling and polluting groundwater. Third, it is necessary to try to implement battery producers to be responsible (or entrusted) to recycle and dispose of waste batteries, so that the responsibility for waste disposal is clear, the sweet and bitter all-inclusive is fair, and the source of materials is regenerated.

In short, large-scale energy storage batteries are an important event to achieve the goal of double carbon. It should be done short-term, with a long-term perspective, overall planning, and practical implementation.