去年年底，一篇发表于国际顶级能源类期刊《Journal of Power Sources》的学术论文引起了业内关注，该论文首次采用了真实商业化的全极耳大圆柱电池，验证了12分钟超级快充的可能性，全面展示了开发成熟的全极耳大圆柱电池的巨大潜力。值得一提的是，这篇文章采用的电芯来自中国制造商，在国内率先发布4680电芯的比克电池。
"The king of the industry", "the best solution of medium and high-end electric vehicles in the next 5-10 years", "may be the ultimate technical direction of power batteries"... For large cylindrical batteries, the industry is generous in praise. Tesla CEO Musk said that all future electric vehicles of Tesla will use 4680 large cylindrical batteries. He said ambitiously that the company's future goal is to expand the 4680 battery capacity to 1000 GWh per year.
"Rapid Leap Forward" of Large Cylindrical Battery
At present, many automobile manufacturers around the world have announced that the large cylindrical battery with innovative lug design will be used in future generations of automobiles. BMW Group said that it plans to use 46mm standard diameter large cylindrical battery in "new generation" vehicles from 2025. Weilai, Porsche, Jianghuai, Dongfeng Landu, Junfeng and other complete vehicle manufacturers also said that their vehicles will carry 4680 large cylindrical batteries, and Daimler, Volkswagen, Xiaopeng, FAW, etc. are also considering using them.
In terms of battery manufacturers, domestic Ningde Times, Yiwei Lithium Energy, Bike Battery, Vision Power, foreign Panasonic, LG New Energy, Samsung SDI, etc. have confirmed that prototype development of 4680 cylindrical battery is under way. Industry research institutions pointed out that in the next few years, it is expected that more automobile enterprises and battery manufacturers around the world will follow the trend of 4680 battery structure innovation, which may become a turning point for large-scale application of cylindrical power batteries.
At the beginning of the new year, the big cylindrical battery circuit has opened the "super burning mode", and many players have repeatedly "lit their swords". On January 28, the Changzhou production base project of Bike battery, with a total investment of 13 billion yuan, was signed to build a large cylindrical battery production line and an international research and development center, with a total capacity of 30GWh after completion. According to the plan, Bike will expand its battery capacity of 80GWh at home and abroad in the future. Recently, Tesla announced that it plans to invest an additional $3.6 billion in Nevada, the United States, to expand its existing super factory, which includes the production of 4680 large cylindrical batteries, and the planned annual capacity of 100GWh.
In addition, according to media reports, General Motors hopes to shift from soft battery to round battery in future electric vehicles. So far, General Motors has been using the soft battery made by LG New Energy. "General Motors is likely to use the 4680 large cylindrical battery pioneered by Tesla in the future," the media commented.
In the future, the installed capacity of large cylindrical batteries is expected to increase as the yield of large cylindrical batteries increases and the cost decreases. Bike battery predicts that the large cylindrical battery will occupy an absolute leading position in the medium and high-end automobile market from 2025 to 2035. Fan Wenguang, Vice-President of Bike Battery, pointed out that the current power battery market is divided into three parts: square shell, soft bag and cylinder. The performance advantages in all aspects determine that the large cylinder power battery is the best solution for medium and high-end electric vehicles in the next 5-10 years.
According to the research report of Everbright Securities, under the background of high sales volume of Tesla and the continuous maturity of 4680 technology, it is expected that the global installed capacity of 4680 batteries will reach 264 GWh in 2025, and the penetration rate in the global installed capacity of power batteries and cylindrical batteries will reach 22% and 68% respectively.
Super "hexagon player"
Technically, the large cylindrical battery can be called "hexagonal player", and its performance is the most balanced in all aspects.
At present, cylindrical battery has the highest safety among several mainstream forms, which is mainly due to the structural characteristics of its monomer and battery package, the smallest monomer and effective risk dispersion; Separate enclosure protection and independent pressure relief device, multiple guarantees; The cells are arranged in honeycomb shape, and the gap ensures sufficient heat exchange area between the monomer and the outside; More importantly, the center-symmetric circular structure can effectively restrain the expansion of the internal electrode during the whole life cycle, so that no deformation occurs outside the core.
"The high safety of the big cylinder makes it the best carrier for carrying both high energy and super fast charging." An industry analyst pointed out. The large cylindrical battery can further improve the fast charging performance while ensuring safety and sufficient range, and help the use experience of electric vehicles to be comparable to that of fuel vehicles.
At the end of last year, an academic paper published in Journal of Power Sources, a top international energy journal, attracted the attention of the industry. The paper first adopted a real commercial full-pole ear large cylindrical battery, which verified the possibility of 12-minute ultra-fast charging, and fully demonstrated the huge potential of developing mature full-pole ear large cylindrical battery. It is worth mentioning that the cell used in this article is from a Chinese manufacturer, which is the first to release the 4680 cell battery in China.
Through simulation calculation and experimental verification, this paper explores the optimal charging time and thermal management strategy of the battery cell under several conditions, so that the battery can be charged from 10% to 80% in 11 minutes and 53 seconds at 20 ° C under the premise of no lithium precipitation of the battery cell; Under the environment of minus 20 ° C, the fast charging time of 10% - 80% can be optimized to the level of 15 minutes and 58 seconds. These findings provide the industry with the prospect of fast charging performance of large cylindrical batteries: it takes less than 12 minutes to change from 10% state of charge to 80% state of charge.
To explore, the essence of fast charging performance is still the energy density of the system, because shorter charging time and higher energy density can be said to be the relationship between fish and bear's paw, and the improvement of fast charging performance is bound to challenge the energy density. The high safety upper limit of the large cylindrical core allows it to support chemical systems with higher energy density. For example, high-nickel ternary anode, silicon-carbon anode, etc., these are systems that are difficult to realize application on square and soft package and other parallel electrode structure cores.
In terms of cost, the advantages of large cylindrical battery are also very obvious. For example, the manufacturing cost of Tesla 4680 cylindrical cell is about 17% lower than that of 2170 cylindrical cell, and the production speed can be increased by up to 7 times. Musk hopes to reduce the cost of 4680 to US $70/kWh in the future. It is estimated that its battery production cost will decrease by about half compared with the current domestic power battery production cost in China.
Different from Tesla's all-pole ear technology
Although the large cylindrical battery has excellent performance and broad application prospects, there are not many enterprises with mature technology in the world at present, and Bike battery is one of the best. It is understood that since the first all-pole ear large cylindrical battery was released in China at the beginning of 2021, BIK has continued to take the lead in the research and development of large cylindrical battery technology and the promotion of marketization. By analogy with Tesla's concept of non-polar ear, after years of exploration, Bike battery has formed a unique all-polar ear technology route.
Through the optimization design of structural parts and the cooperation of production equipment and tooling fixtures, Bike all-pole ear technology has realized a process solution that is more efficient than the traditional cylindrical cell. According to the test, the internal resistance of the cell with full-pole lug is reduced by more than 70% compared with the traditional single-pole lug cell of the same system. This means that the extremely high power input (charging) and output (discharging) are widely recognized by international customers.
With the structural advantages of the large cylinder, Bike has greatly improved the energy density of the battery by carrying advanced technologies such as high nickel positive electrode, silicon negative electrode, and silicon-doped lithium supplement, providing the vehicle with a range of more than 800 kilometers. At present, the nickel content of the positive pole of Bike cylindrical battery has been increased from Ni50 to Ni90, and the capacity continues to increase. At the same time, Bike silicon oxide materials have also developed from the first generation of silicon to the third generation of silicon, increasing the first efficiency from 77% to 86%, basically matching the efficiency of the positive electrode, and using advanced lithium supplement technology, the utilization rate of the positive electrode has gradually improved.
It is reported that there are mainly 46 series, 3x series and 26 series of BIK cylinders. Among them, 46 series of cores have been delivered in batches, and their performance meets expectations. At present, the energy density of the cell is between 280Wh/kg and 330Wh/kg. The 26 series is mainly made of 26105 aluminum shell cells, which are currently in the B-type stage, and can be applied to the whole vehicle for more than 700km. It is expected to be mass produced in 2024, when the energy density will reach 290Wh/kg. The 3x system is in the middle of the two. It is a new platform developed by Bike to further optimize performance, cost, system design and other factors.
With the support of all-pole ear technology, advanced chemical system and battery design capability, the large cylindrical product that will be produced in mass production by Bicke can realize the fast charging of electric power from 10% to 50% in 5 minutes, which is equivalent to 200-300Km range, and from 10% to 80% in 12 minutes, which is equivalent to 520 km range. At the same time, it supports the super fast charging demand of more than 4C charging rate in application scenarios such as high-speed service stations, It is almost the same as the current fueling experience of fuel vehicles. This data has also been verified by experimental data in the above-mentioned academic papers.
In terms of the safety that consumers attach great importance to, through the structural design, the BIK large cylindrical battery can realize the directional pressure relief of the cell, ensure that when the single cell is out of control, it will not spread to the surrounding cells to produce a chain reaction, and ensure the thermal safety of the whole package level, so as to achieve zero thermal diffusion at the vehicle level, and ensure the overall safety of the battery package and the consistent quality of the whole life cycle of the battery.
In the future, large cylindrical batteries will definitely show their skills. Canalys, a market research institute, predicts that the global sales of electric vehicles will exceed 20 million in 2025, and the corresponding demand for power batteries will exceed 1600 GWh. The industry speculates that by 2025, the large cylindrical cell will account for at least 30% of the global power battery market share, which will exceed the global power battery total demand in 2021.
It is not hard to imagine that the spring of the large cylindrical battery is coming, which will also boost the development of the global new energy vehicle industry to a higher stage!