It is said that the electric vehicle battery copper foil manufacturers under the South Korean SK Group announced that it has developed a high extension copper foil for 4680 batteries -an extension rate may be 30%higher than other products.
On September 9, the BMW Group announced that in order to meet the needs of the "new generation" model for batteries, it will be the first to use large cylindrical batteries in the "new generation" model since 2025. The two partners can sign a battery production demand contract worth more than 10 billion euros. According to the agreement, the latter will start to supply BMW's large cylindrical batteries in 2025.
BMW's large cylindrical battery is a cylindrical battery with a diameter of 46 mm and a height of 95 or 120 mm, similar to Tesla's 4680 (46 mm diameter and 80 mm) cylindrical battery. Therefore, BMW's large cylindrical battery is also called "quasi 4680" battery.
Driven by Tesla, the electric vehicle industry set off a 4680 battery boom. More and more auto companies have switched from square batteries and soft -bag battery routes to tracking cylindrical battery technology routes.
According to predictions, it is expected to become the first year of mass production in 4680 batteries in 2023. The installation volume of 4680 battery was expected to exceed 20 Gavaco, and in 2024, it will exceed 100 Gavacan.
The batteries used by electric vehicles are divided into three types: square, cylindrical, and soft bags according to the shape and packaging form. The square and cylindrical batteries use metal hard shells. The soft bag battery uses aluminum -plastic composite film.
The earliest Tesla used the small cylindrical 1865 battery produced by Panasonic, Japan, that is, the battery diameter was 18 mm, the height was 65 mm, and the specifications were later expanded to 2170. The 4680 battery developed. Tesla believes that the diameter of 46 mm is the best diameter of economic and battery performance. In terms of height, flexible adjustments can be made according to the needs of the model.
From a structure, the biggest feature of the Tesla 4680 battery is the use of Wuji ear (also known as the pan pole ear) technology. The so -called pole ear is a metal conductive body led to the positive and negative pole from the cylindrical battery. The main component is aluminum and copper. It is the contact point for the battery to charge and discharge. In the lithium battery, the electrons move between the positive ears and the negative ears. The circulation path is proportional to the internal resistance, and the internal resistance is correlated with the internal loss of the battery. Therefore, Wuji ear design can shorten the electronic circulation path, reduce the internal resistance and heat production of battery, and bring higher output power and better fast charging performance.
From the perspective of the material system, the 4680 battery will be more adapted to new material systems such as high nickel ternary and silicon negative poles than square batteries. First, the disadvantage of cylindrical batteries is that the group efficiency is about 70%, and 80%lower than the square battery. If you want to achieve the same energy density as the square battery, you must use more efficient solutions. Using high nickel triple materials and silicon silicon must be used. The negative electrode system; second, the negative expansion coefficient of silicon negative poles has a higher expansion coefficient. The cylindrical battery is more uniform than the internal stress distribution of the square battery, which is not easy to cause internal materials to damage.
The advantages of cylindrical battery single height consistency make the 4680 battery more adaptable to 800 volt high voltage and solve the problem of fast charging of electric vehicles; because cylindrical batteries have better structural support than square and soft bag batteries, 4680 batteries will also promote promoting The industrial change of the "battery cell to the bottom disk" (CTC) technology.
Therefore, the 46 series large cylindrical battery is considered the development direction of the next generation of cylindrical batteries. Tesla announced in September 2020 that compared with the 2170 battery, the 4680 battery capacity can be increased by 5 times, the output power increases by 6 times, the cost per kilowatt -hour is reduced by 14%. Essence In terms of charging, it only takes 15 minutes to charge the power from 10%to 80%in the 400 volt high -voltage fast charge mode.
BMW said in September 2022 that the 46 series of large cylindrical battery forms and chemical systems (high nickel ternary and silicon negative material system) can increase battery life by 30%. It will be reduced by 30%at 80%.
There are also analysis that the 4680 battery also has the disadvantages that cannot be ignored: on the one hand, the 4680 battery and the CTC structure make the battery extremely poor maintenance and high maintenance cost; on the other hand As a result, some models equipped with 4680 batteries have poor protection on the side of the body.
At the same time, Wuji ear technology has also brought challenges in the 4680 battery production process. These difficulties are distributed in multiple links such as division, injection, flatness, and laser welding. Among them, the biggest problem is in the laser welding session -from the point welding of two polar ears to the omnipotent ear welding, the welding process and the amount of welding have increased, and the laser intensity and focal length are not easy to control. Internal may not be welded. This link will directly affect the yield of 4680 batteries.
Globally, many battery companies and automobile companies such as Tesla, Panasonic, LG, Samsung, Ningde, and other battery companies are densely deployed 46 series of large cylindrical batteries.
