With the continuous leap in the installation of renewable energy, its volatility and intermittency also bring about a certain impact on the grid. In this case, the role of energy storage is highlighted, and it is also attracting more and more attention in the industry. To better understand energy storage and develop energy storage battery technologies, we recommend:
First of all, we must clarify the basic concepts. The energy storage battery technology includes the energy storage battery body technology and the energy storage battery application technology, both of which are very important.
In a broad sense, energy storage is the use of some device or method to store energy and release it after energy is moved in the spatial dimension or released after being stuck in the time dimension. Based on this, it can be further subdivided into two categories: mobile energy storage, that is, energy supply for mobile devices, power batteries for electric vehicles, etc.; static energy storage, such as UPS power supplies, communication base station power supplies, industrial heat storage systems, and pumped storage power stations. In addition, the use of natural plant photosynthesis or artificial photosynthesis of new photochemical conversion materials, which converts light energy into biomass energy or chemical energy and stores and releases it, is also an important class of static energy storage methods.
According to the energy forms used, energy storage technology can be roughly divided into four categories; physical energy storage (pumped energy storage, compressed air energy storage, flywheel energy storage, superconducting energy storage), electrochemical energy storage (secondary (batteries, electrochemical supercapacitors), chemical energy storage (artificial clean energy such as hydrogen storage, carbon storage, and other chemical reaction energy storage), heat storage / cold storage (sensible heat storage, phase change energy storage, chemical reaction heat storage). Energy storage batteries belong to the category of electrochemical energy storage and are currently the most rapidly developing type of energy storage technology.
However, not all batteries can be called energy storage batteries. The system power is in the order of 1KW or more. The batteries used for electric vehicles and communication base stations can be called energy storage batteries; the system power is ≥1MW, which is used for energy storage power stations. The battery is called a power storage battery.
Energy storage battery application technologies mainly refer to BMS (Battery Management System), PCS (Battery Energy Storage System Energy Control Device), and EMS (Energy Management System). BMS is the link between the battery body and the application. The main object is the secondary battery. The purpose is to improve the utilization of the battery and prevent the battery from overcharging and overdischarging. The PCS is a system that is matched with the energy storage battery pack and is connected between the battery pack and the grid to store the grid electrical energy in the battery pack or to feed the battery pack energy back to the grid. EMS is a general term for modern grid dispatch automation systems, including computers, operating systems, EMS support systems, data acquisition and monitoring, automatic generation control and planning, and network application analysis.
Secondly, demand-oriented, according to the actual needs of different applications in the development of appropriate energy storage battery technology; low cost, long life, high security, easy recycling is the overall goal of energy storage battery technology development.
Energy storage can play an important role in many aspects, such as power grid peaking and frequency regulation, smooth renewable energy generation fluctuations, improved distribution quality and reliability, base station, community or home backup power, distributed micro-grid energy storage, electric vehicle VEG mode Energy supply system. The energy storage applications have different scenarios and technical requirements. No battery of any kind can meet the requirements of all scenarios. Therefore, demand-oriented, according to the actual needs of different applications in the development of appropriate energy storage battery technology.
The current high cost of energy storage technology and poor economic performance are common problems. The cost reduction of energy storage technology can be divided into four target phases. Current objective: To develop non-peaking energy storage battery technologies and markets, such as the electric vehicle power battery market, off-grid market and power FM market; short-term (5 - 10 years) target: the cost of electricity below the peak-valley price difference Medium-term (10-20 years) target: lower than the cost of thermal power peaking (and dispatch); long-term (20-30 years) target: lower than the cost of electricity for wind power generation during the same period.
Although the current business model of energy storage using peak-to-peak electricity price spreads has received considerable attention, this may be a false proposition. It is feasible in the short-term and it is not feasible in the long-term. The reason is that with the decline in the cost of energy storage technology, the peak-to-valley electricity price difference in the grid will become lower and lower. In the future, energy storage equipment may be included as an important supplement to the grid dispatch system only when the energy storage cost is lower than the thermal power peaking cost.
There is a potential crisis in existing types of energy storage batteries. Sodium-sulfur batteries and ceramic tubes have been damaged due to aging. Lead-acid (lead-carbon) batteries, lead concentrates were mined in about 15 years; low-cost, high-pollution recycling links. All vanadium flow batteries, the system efficiency is lower than 70% of the "ceiling"; toxic vanadium sulfate solution; diaphragm for the battery rate and electrolyte cycle life can not take into account; system complexity, operational reliability problems. Lithium-ion batteries: The current battery structure is difficult to handle and costs high; the battery has hidden safety problems and the application costs are high.
In summary, low-cost, long-life, high-security, and easy-to-recovery are the overall goals of energy storage battery technology development.
Third, we must attach great importance to the basic innovation research and the layout of intellectual property rights for large-scale electric energy storage battery technologies, and at the same time promote the commercial sharing of intellectual property rights for energy storage battery technologies.
With the application of energy storage scale, large-scale energy storage technology is the future development trend. The development of ultra-high-power safe energy storage battery technology with single-cell power ≥100 KW will be an important research direction. To solve the application problems as the core, we must use small batteries as the idea to make small batteries, and use bigger batteries as the idea to build larger batteries. We cannot use the structure of small batteries to make large-scale power storage batteries.
In addition, our current understanding of the application of energy storage technology and the nature of energy storage technology may still be preliminary and superficial. Power storage is a concept of system storage/discharge, and it is likely that a combination of multiple technical and economic models is needed, rather than being confined to the understanding of the charging and discharging behavior of a single battery cycle.
China’s foreign intellectual property rights are as high as 60%, and in terms of core technology, the dependence on foreign intellectual property in China has even reached more than 90%. In the process of strengthening basic science exploration and research and development of original innovation technologies, energy storage technology must strengthen the evaluation of intellectual property rights and evaluation of technology application prospects for the establishment and conclusion of energy storage projects.
For energy storage technologies that have matured or have entered demonstration applications in foreign countries, how can we break through the layout and blockade of related intellectual property rights? In this regard, it is proposed to establish an evaluation and trading platform for intellectual property rights in the energy storage industry to guide the orderly development of the energy storage technology industry chain; establish and improve the protection and commercial sharing mechanisms for intellectual property rights, strengthen the patent layout of core technical points, and actively guide industrial capital and risk The investment will enter the frontier technology development field and improve the independent innovation capability of the energy storage industry.
Finally, based on the energy storage (battery) technology level to develop the energy storage industry in a realistic manner, it is imperative to carry out large-scale megawatt-level demonstration applications under the premise of safety and reliability of energy storage battery technology.
In the power industry, safety is the primary consideration and the application of energy storage is no exception. The safety, reliability, and economics of energy storage battery technology are the prerequisites to determine whether it can be used on a large scale.
The difference and connection between energy storage battery body technology and energy storage battery application technology must be clearly defined. For most energy storage battery technologies, when the technology is used for demonstration applications above megawatt level, it is mainly to find out and solve technical problems and economic evaluation in the application process of energy storage systems, rather than the energy storage battery technology. The problem. In other words, under the premise of safe and reliable energy storage technology, a demonstration application above megawatt level should be carried out. The purpose of the demonstration application is to accumulate application data, develop application technologies, solve application problems, and evaluate application economics. If the demonstration project is progressing smoothly, its large-scale promotion will also be rolled out gradually, and the energy storage industry can develop healthily.