| The iteration of large-capacity batteries is a double-edged sword, which not only reduces costs and accelerates market development, but also brings potential safety hazards and technical problems. |
Text | Wang Fangyu
Edit | Su Jianxun
Despite the controversy in the industry, the capacity of lithium battery energy storage cells has become larger and larger in the past two years.
In 2020, the 280Ah (ampere-hour) battery products, which focus on long cycle life, were introduced to the energy storage market, quickly replacing the original specifications and becoming the mainstream of energy storage power station applications;
By the second half of 2023, although the mainstream in the market is still 280Ah, the head energy storage cell factory will once again lead the way, launching a 500Ah+ super-large battery, which will directly nearly double the cell capacity.
According to incomplete statistics of 36 carbon, up to now, EVE Lithium Energy, Xiongtao Co., Ltd., Haichen Energy Storage, Honeycomb Energy and other manufacturers have launched 500Ah+ energy storage super large cells. In particular, CATL, an industry leader with wind vane significance, has started the construction of a new production line of 530Ah energy storage cells in December last year.
However, since the industry launched the 300Ah+ large battery cell, the controversy surrounding the large battery cell has continued. Industry experts represented by Ouyang Minggao, an academician of the Chinese Academy of Sciences, pointed out the safety problems brought about by 300Ah+ energy storage large cells - the larger the battery, the higher the risk of thermal runaway accidents.
Nowadays, the capacity of energy storage cells has been increased to 500Ah+ again, which undoubtedly puts forward more stringent safety requirements for lithium battery energy storage body, process and fire safety.
Li Yanming, deputy secretary-general of the Energy Storage Leader Alliance, told 36 Carbon: "For the sake of safety and maturity, the real market application of large battery cells still needs to go through the test of the market, which still requires process and time." The temperature control system and BMS technology of matching cells need to be improved. "In short, the technology and application of ultra-large cells are still not fully mature.
When ultra-large cells encounter safety problems, can energy storage cells successfully enter the 500Ah+ era, and will the trend of increasing cell capacity continue?
01
Driven by the demand for cost reduction, energy storage cell factories have set off a capacity competition
The reason why the battery cell capacity is getting bigger and bigger, the biggest driving force for energy storage battery manufacturers is to reduce costs to seize the downstream market.
Large-capacity batteries are mainly used in large-scale energy storage scenarios on the grid side and power supply side, and cost reduction is still the core demand of downstream power station investors in the context of the general lack of economics in the domestic energy storage market segment. Large-capacity batteries have significant cost reduction advantages and can bring better price competitiveness to manufacturers.
Song Feng, founder of Vilion, told 36 Carbon: "Ultra-large capacity cells will reduce the number of clusters and reduce the cost of cluster management and other relative peripherals, so it has a good cost-reducing effect on large-scale storage projects." ”
Taking 300Ah+ cells as an example, most of the 300Ah+ energy storage cells still use the size of 280Ah cells from the same manufacturer (71173), so the energy density is higher in the same volume, thereby reducing the overall energy storage system cost and improving the project income. In the promotion of 300Ah+ battery cell products of energy storage battery manufacturers, cost reduction is also one of the most prominent selling points.
However, the cost reduction of the energy storage system through product and technological innovation is achieved through product and technological innovation, which is essentially different from the cost reduction of the price war.
In this context, the mass production of 300Ah+ cells has also become the embodiment of the product and technical competitiveness of lithium battery enterprises. The leading energy storage manufacturers have launched 300Ah+ cells, setting off a race to upgrade from 280Ah to 300Ah+. According to incomplete statistics of 36 carbon, more than 20 domestic battery manufacturers have launched energy storage cells with a capacity of 300Ah+.
The capacity of mainstream energy storage cells is getting larger and larger Image source: Visual China
Further achieving the battery cell capacity to 500Ah+ is a continuation of the product and technology competition of energy storage cell manufacturers. "At present, the market competition is too fierce, and energy storage battery manufacturers want to open up the gap with their opponents through differentiated products. An industry analyst said.
EVE is the first manufacturer in China to release 500Ah+ battery cells, and it released a 560Ah ultra-large capacity LF560K energy storage battery in October 2022. Another leading energy storage battery manufacturer, Haichen Energy Storage, released the long-term energy storage battery MIC 1130Ah in December last year, which increased the capacity to 1130Ah in a "leapfrogging" manner, which is four times the capacity of the 280Ah battery and the largest capacity energy storage cell that has been released so far.
For downstream customers, the core competitiveness behind ultra-large cells still lies in further cost reduction. As the cell capacity has become larger, the number of cells and components used in system integration is reduced, and the effect of 500Ah+ super large cells in reducing costs is also more prominent.
Compared with the 280Ah system products, EVE claims that the 560Ah large battery cell can reduce the cost of system integration applications by 10%, and Haichen Energy Storage claims that the 1130Ah super large battery cell can help the DC side energy storage system reduce the cost by 25%.
It is worth mentioning that with the increase of the capacity of energy storage cells, the corresponding technical difficulty and threshold have also increased accordingly - super-large cells are not proportional amplification of large cells, but involve a series of complex problems in materials, design and manufacturing. At present, there are dozens of energy storage cell factories in China, and there are only more than 20 manufacturers that have launched 300Ah+ cells, and only 5 or 6 have launched 500Ah+ cells.
Yi Ziqi, chief technology officer of Haichen Energy Storage, told 36 Carbon that the R&D cycle of Haichen's 1130Ah super-large battery cell is nearly two years, and it is a strategic product that can maintain market competitiveness in technology.
02
Large cells are a trend, but they pose new challenges to safety
On the one hand, the capacity of energy storage cells is getting bigger and bigger, but on the other hand, the controversy caused by large-capacity energy storage cells has also continued.
In May last year, Ouyang Minggao, an academician of the Chinese Academy of Sciences, pointed out at the CIBF2023 conference that 300Ah+ lithium iron phosphate energy storage cells are actually more dangerous in terms of intrinsic safety.
Ouyang Minggao said that the internal temperature of large-capacity batteries like 320Ah batteries can reach 700 to 900 degrees, which exceeds the temperature of lithium iron phosphate cathode decomposition (500 degrees). In addition, with the increase of SOC (state of charge of battery cells), the proportion of hydrogen produced by thermal runaway of large-capacity lithium iron phosphate batteries increases, and the explosion index is twice that of ternary batteries.
Wang Xujun, manager of production planning and material control of Times United New Energy, told 36 Carbon that the larger the battery cell, the more difficult it is to dissipate heat and ensure the consistency of the internal temperature of the battery cell, and the thermal runaway problem after the battery short circuit will be more prominent.
Jiang Xinyu, chairman of Zhiguang Energy Storage, also questioned the rapid increase in battery cell capacity at a public meeting last year. He said that in 2021, most manufacturers are still pushing samples of 280 battery cells. However, in 2023, the 2021 product is already outdated, and in the next two or three years or more, it may be questionable whether energy storage projects using 280 cells can find 280 cells to replace the battery compartment. He reminded practitioners, "When one technology is not stable, we will cross over to another technology, which will bring a mess to the industry." ”
At present, 280Ah battery cells are the mainstream of the market Image source: Visual China
Therefore, in the eyes of many industry insiders, the iteration of large-capacity batteries is a double-edged sword, which not only reduces costs and accelerates market development, but also brings potential safety hazards and technical problems. There is a view that CATL, as the leader of 280Ah large battery cells, launched 300Ah+ battery cell products late, mainly because of its safety concerns.
At present, 280Ah battery cells are still the mainstream of the market, but since the third quarter of last year, more and more 300Ah+ large battery cell projects have been put into project application and are accelerating their penetration. The world's leading energy storage system integrators, such as Sungrow and Powin, have purchased and applied 300Ah+ battery cells.
According to this, many people in the industry believe that 300Ah+ cells will be "the standard configuration of the next generation of energy storage large cells". (300Ah+ cells include 314Ah, 315Ah, and even 320Ah, although the numbers are slightly different, but the lower limit of capacity is the same, and the products are all similar.) ）
Gaogong energy storage analysis believes that in the future, who can quickly obtain the "safety key" of 300Ah+ energy storage cells will quickly become the leader in this track. However, at the same time, it is also pointed out that the safety of "300Ah+" large-capacity batteries is still a problem that other second- and third-tier brands urgently need to solve.
From another point of view, the continuous penetration of 300Ah+ battery cells is also forcing battery cell companies to accelerate safety upgrades, promoting the progress and improvement of battery heat dissipation and safety technology in the industry.
As for whether 500Ah+ batteries can continue to penetrate in the future, and even become mainstream, it is facing greater controversy and greater uncertainty.
Envision Power is the first enterprise in China to achieve large-scale mass production of 300Ah+ battery cells, and launched the first special battery cell for energy storage in 2019. Qian Zhenhua, chief engineer of energy storage products of Envision Energy, told 36 Carbon that the development of energy storage cells to larger capacity will be an inevitable trend in the future, and more companies will launch larger-capacity energy storage cells to help the industrial chain mature rapidly. Sun Wei, president of Trina Energy Storage, also said that in the future, the battery capacity will be further increased than the existing battery, and it may exceed 500Ah in other sizes.
However, the capacity of the battery cell is not infinite. Li Yanming said that with the increase of cell capacity, battery thermal management has become an important problem. If the battery cells do not withstand the test and feedback of sufficient quantity and time, and the excessive pursuit of large capacity and new technologies, the consistency of the battery will not be guaranteed, which will bring operational risks to the energy storage system.
At present, 500Ah+ ultra-large batteries have not yet achieved large-scale mass production and delivery, and it will take time to penetrate the market. It is reported that EVE's LF560K battery is expected to start global delivery in the second quarter of this year, and Haichen Energy Storage's 1130Ah battery cell is expected to start global delivery in December this year. The 530Ah battery cell production line of CATL also started construction in December last year.
And there is also uncertainty about the acceptance of 500Ah+ by downstream customers. Yi Ziqi said that at present, 280Ah and 314Ah are in a very balanced stage, from the perspective of the project, some projects that are willing to break through will choose 314Ah, and the more conservative will choose 280Ah and reject new products.
In the long run, it depends on who can maintain the lowest cost on the basis of high safety to determine how big the optimal solution is for the future cell capacity and which specification of the product can become the mainstream of the market. All this is yet to be answered by the market and time.
| The title image of this article comes from Visual China