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This is a very interesting question. According to the statistics of Energy Storage Application Branch of China Industrial Association of Power Sources, the cumulative installed capacity of chemical energy storage in China ranked second in 2017, reaching 385.0 MW, of which lithium-ion battery installed the largest, reaching 60%.

Don't rush to give answers to the questions raised in the opening section, and listen to what the professionals say.

Not long ago, Mr.Peng, general manager of Shanghai New Energy (Hefei) storage Tech. Co., Ltd., said in an interview with ESCN （China Energy Storage Network）that there are basically no real energy storage batteries in the market, and none of the major power battery manufacturers have Invest in a dedicated energy storage cell production line.

If the statement from Mr.Peng is correct, then this means that the China's 231 MW lithium battery energy storage project is not a dedicated lithium battery for energy storage. What lithium batteries are used in these projects?

The author consulted a number of industry insiders, the answer is the power lithium battery. Then the problem is, the power lithium battery can be used in energy storage projects. Is this the God's truth of best choice or have no alternative to choice? What are the differences between power lithium batteries and energy storage lithium batteries?

From the application scenario, power lithium batteries are mainly used in electric vehicles, electric bicycles and other power tools, while energy storage lithium batteries are mainly used in peak-adjusting frequency-frequency auxiliary services, renewable energy grid-connected and micro-grid.

Battery performance requirements vary depending on the application scenario. First of all, as a mobile power source, the power lithium battery has as high a requirement as possible for the volume (and mass) energy density under the premise of safety, in order to achieve a longer lasting endurance. At the same time, users also hope that electric vehicles can be safely and quickly charged. Therefore, power lithium batteries have high requirements for energy density and power density, just because safety-type batteries with 1C charge and discharge capacity are widely used for safety reasons.

Most energy storage devices do not need to be moved, so energy storage lithium batteries do not have direct requirements for energy density. As for the power density, different energy storage scenarios have different requirements.

The Leader of Energy Storage Technology Research Group of INSTITUTE OF ELECTRICAL ENGINEERING,CHINESE ACADEMY OF SCIENCESE,Mr.Chen has pointed that, for power peaking, off-grid PV energy storage or user-side peak-to-valley difference energy storage scenarios, generally need The energy storage battery is continuously charged or continuously discharged for more than two hours, so it is suitable for a capacity type battery with a charge and discharge rate of ≤0.5C; for energy storage scenarios where power frequency modulation or smooth renewable energy fluctuations are required, the energy storage battery needs to be in the second to the minute. The stage time is fast charging and discharging, so it is suitable for the application of ≥2C power battery; while in some applications that need to bear the frequency modulation and peak shaving, the energy battery will be more suitable. Of course, the power can also be used in this scenario. The type is used in conjunction with a capacity type battery.

Secondly, compared with power lithium batteries, energy storage lithium batteries have higher requirements for calendar life. The life of new energy vehicles is generally 5-8 years, and the life of energy storage projects is generally expected to be more than 10 years. The life cycle of the power lithium battery is 1000-2000 times, and the life cycle of the energy storage lithium battery is generally required to be more than 3500 times, and it is hoped that a new type of operation and maintenance technology can be developed to achieve an ultra-long calendar energy storage life.

Third, in terms of cost, power lithium batteries are facing competition from traditional fuel power sources, and energy storage lithium batteries need to face the cost competition of traditional peaking and frequency modulation technology. In addition, the scale of energy storage power plants is basically above the megawatt level or even 100 megawatts. Therefore, the cost of energy storage lithium batteries is lower than that of power lithium batteries, and the safety is also required.

It can be seen that there are many differences between power lithium batteries and energy storage lithium batteries. With the gradual release of the energy storage market, the domestic special energy storage lithium battery production line has not officially started. The underlying reason behind this may still be that the demand for the energy storage market is not stimulated enough, so the battery manufacturers' people and property are all concentrated on the power battery. In addition, research and development of energy storage battery technology for different energy storage application scenarios is not enough, and there is still a certain distance from industrialization.

Of course, the market demand for energy storage and market supply may be “first chicken or egg first” in many cases. This is because the supply of cost-effective energy storage lithium batteries is not enough, or because the demand is not Wang can not pull the supply of cost-effective energy storage lithium battery?

There are a thousand Hamlets in a thousand people's eyes. However, Mr. Huang, vice chairman of CATL, publicly opposed the use of power batteries, especially backward power battery capacity, in energy storage projects.

He publicly stated, "Many people say that excess power battery capacity can be used for energy storage. Actually there is a big misunderstanding here." "Energy storage batteries are more demanding than power batteries, and backward power battery capacity may gradually be Eliminate."

Therefore, we believe that on the eve of the outbreak of the energy storage market, facing the difference between energy storage batteries and power batteries, it is a wise choice to lay out the development and production of energy storage batteries in advance.

Source:ESCN

Link:http://www.escn.com.cn/news/show-696707.html