(report producer/author: West China Securities Yu Nengfei )
1. Tesla first recommended 4680, new technology helps the battery break through the limit
1.1. The process has changed, and the battery performance has been greatly improved
Lithium-ion battery According to different packaging forms, the battery is divided into cylindrical batteries, square batteries and soft-pack batteries.
cylindrical batteries have the longest development time, the most mature technology, and their degree of standardization is relatively high; square batteries have a high popularity in China and simple production process; soft-pack batteries adopt superimposed manufacturing methods, which are thinner and smaller in volume than the other two types of batteries.
Tesla tried to make it more suitable for the needs of electric vehicles by increasing the size of cylindrical batteries.
Tesla released the "4680 battery" on "Tesla Battery Day" in September 2020, that is, a cylindrical battery with a diameter of 46mm and a height of 80mm.
Compared with 18650 and 21700 batteries, 4680 is larger in size and has higher energy density.
According to Tesla's introduction at the 2020 Super Battery Day, the energy of the 4680 battery cell has been increased by 5 times and the output power has been increased by 6 times. In combination with the new assembly process, the battery life of the electric vehicle can be increased by 54%, the battery price per kilowatt-hour is reduced by 56%, and the production cost is reduced by 69%. On the one hand, the design and production process of
4680 batteries are innovative. For example, the 4680 batteries released by Tesla mainly use the following important technologies:
1) Use poleless ears to establish a new standard for winding battery cells;
2) The negative electrode uses a silicon-based negative electrode to break through the energy density limit of existing lithium battery materials;
3) Use dry electrodes to establish a new standard for power batteries.
1.2. The unmistakable ear technology reduces the internal resistance of the battery, taking into account performance and safety
pole ear is a metal conductor derived from the positive and negative current collector of the battery. It is connected to the battery case (cylindrical/square) or to the external module structural parts (soft package). The current must flow through the pole ear to be connected to the external battery.
According to the number and area of the electrode ears, the electrode ears can be divided into single-pole ears, bipole ears, multi-pole ears and unpole ears (also known as full-pole ears). The 18650 or 21700 battery has a small size and mostly uses the single-pole ear method. The slender ears are not conducive to current conduction. When the battery is charged and discharged, it is very easy to cause excessive local heat at the connection between the electrode ears and the electrode ears, which becomes a key bottleneck affecting battery safety.
pole-inverted ear battery turns the entire positive/negative current collector into the pole ear.
is connected to the battery case or current collector through the full area of the current collector, which greatly reduces the internal resistance and heat generation of the battery, solves the heating problem of high-energy-density battery cells, and increases the peak charging and discharge power, helps break through the bottleneck of cylindrical batteries to make them bigger.
Infinite ear does not mean that there is no Infinite ear in the battery structure, on the contrary, many infinite ears are added to the positive or negative electrodes.
According to Tesla's patent, we can see that in the structure of the 4680 battery, there is a uniform electrode distributed on the positive electrode, and the negative electrode does not have an ear structure. The negative electrode is directly combined with the battery case, which is equivalent to the entire battery case becoming a whole negative electrode.
Tesla 4680 pole-less ear battery turns the entire current collector into the pole ear, and the conductive path no longer depends on the pole ear. The current transfers from horizontal transmission along the pole ear to vertical transmission of the current collector. The entire conductive length changes from 800-1000mm of the length of 1860 or 2170 copper foil to 80mm (battery height).
Traditional cylindrical batteries are all wound, divided into positive and negative electrode copper foil and aluminum foil diaphragm and superimposed and wound. In order to lead the electrode, a lead wire is welded at both ends of the copper foil and aluminum foil.
The traditional 1860 battery winding length is 800mm. Taking copper foil with better conductivity as an example, the length of the electrode conducts electricity from the copper foil is up to 800mm, which is equivalent to the current passing through the 800mm wire.
calculated that the resistance is about 20mΩ, and the 2170 battery is thicker and the winding length is about 1000mm, and the resistance is about 23mΩ. In order to ensure low resistance, such a long copper foil will have extremely high requirements for the thickness and consistency of the copper foil.
calculates the resistance of Tesla's poleless ear battery. After substituting the conductive length into the copper resistance calculation formula, the resistance suddenly drops to 2mΩ. According to the Ohm theorem calculation, the battery internal resistance consumption drops from 2 watts to 0.2 watts, which is directly reduced by an order of magnitude.
main advantages of Wujier design are as follows:
1) Improve security.
The last current of the traditional monopole ear will flow out on the monopole ear, so there will be a hot spot for the monopole ear, which is the extreme ear. However, the ink ear battery has no concentrated heat spots inside the battery, and the heat is evenly distributed inside, which will bring a great advantage in thermal management to the entire battery pack. In addition, Tesla's 4680 battery directly takes off the case to dissipate heat.
2) Reduce production costs.
Domestic large cylindrical battery research and development company BIC Battery mentioned that the use of Wuji Ear 4680 large cylindrical control requirements for all aspects of BMS will be much less, and the cost will also be reduced. The capacity of the 4680 electric equipment is 25Ah, while the original 18650 is 3Ah, which is more than 8 times the gap, which means that a battery pack originally required more than 8,000 18650, but now only 1,000 4680 knots.
3) Fast charging performance is improved.
html can charge the battery from 0 to 80% within 0 minutes, that is, a car with a range of 600 kilometers can be stopped at the charging station for 10-15 minutes, which can meet the range of 400-500 kilometers.1.3. The graphite negative electrode has reached the theoretical ceiling, and the silicon-based negative electrode may usher in spring
The current graphite negative electrode is very close to the theoretical capacity ceiling (372mAh/g), and silicon is currently the highest specific capacity among the negative electrode materials. However, the cost of silicon-based anode is currently too high (more than 3 times the normal graphite).
The current mainstream solution is to use silicon oxygen and silicon carbon and then use it after compounding graphite. The conventional models include 400, 407, 420, 450, 550, 650mAh/g, which is generally above 400Mah/g.
Compared with graphite negative electrode materials, silicon-based negative electrode materials have ultra-high theoretical specific capacity and low delitting potential. In the context of gradually increasing the energy density of lithium-ion batteries and the gradual maturity of battery manufacturers' mastery of high-nickel systems, upgrading graphite negative electrode systems to silicon-based negative electrode systems has become the main direction.
In recent years, the application of silicon-based negative electrode materials has gradually developed, and downstream automobile manufacturers represented by Tesla have equipped with power batteries made of silicon-based negative electrodes.
Currently, the two most commercialized silicon-based anode materials are carbon-coated silicon oxide and nano-silicon carbon.
As the continuous improvement of downstream customers' requirements for electric vehicle power batteries, there is a certain room for imagination in the growth of silicon carbon negative electrodes.
1.4. Dry electrode technology supports Wuji ears, the foundation for improving battery performance
The realization of the battery cell technology path depends on dry electrode technology. Dry electrode technology is a positive/negative electrode material pressing technology, which specifically mixes a small amount of fine powdered adhesive (PTFE) with the positive or negative electrode material, forms an electrode material tape through thin film deposition technology, and then calenders on the metal foil current collector to form the finished electrode - ultimately manifested as a substrate covering the electrode film. In the indefinite ear battery cell, Tesla replaces the function of the electrode ear with an electrode film substrate (partially).
is based on dry electrode technology. Its contribution to the winding battery cell is to basically absorb the advantages of the stacked battery cell.
takes the current development trend of the global electric vehicle industry as a reference. Dry electrode technology can be regarded as one of the top achievements of the power battery technology tree. A complete breakthrough in this technology will also mean the official implementation of the next generation of power battery - solid-state batteries.
2.4680 new technology brings equipment demand updates
2.1. Annealing is required before rolling, and the consistency requirements of the coating machine are higher
Before rolling, the white space needs to be heated and annealed. When rolling, the full-pole ear pole sheet has a white space on the pole sheet, and direct rolling cannot ensure that the pole sheet remains flat during rolling, so annealing treatment is required.After the return of
, the aluminum foil grains return to recrystallization, and from a typical rolled strip shape to an isoxial shape. The internal stress gradually eliminates, the plasticity of the aluminum foil increases, the texture becomes soft, and the resistance becomes lower. During the rolling process, the white space can be deformed together with the coating area, the warpage degree of the pole sheet is reduced, and there is no wrinkle in the white space.
full-pole ear plate is different from monopole ears and bipole ears when applied. The positive electrode needs to be left white while the negative electrode can achieve overall coating.
The part of the positive electrode part that has white space is a fish-scale all-pole ear, and the width of the white space is not fixed, so it will put higher requirements on the consistency of the coating machine.
At the same time, using the all-pole ear structure does not require gap coating to leave the pole ear position in the space, but can use continuous coating to improve the coating quality and efficiency.
adopts an all-pole ear structure, and the coating area and coating length of the positive electrode and negative electrode of the single-piece will increase significantly, so the continuous coating requirement of the coating machine is increased.
According to the comparison of the 4680 battery model designed by Lixiang Life with the 21700 and 18650 models, the 4680 battery monolithic positive electrode coating length reaches 627314.83mm, 5.8 times the coating distance of 21700, and the double-sided coating length of the negative electrode reaches 4319.7mm, which is 5 times the 21700 battery, that is, the 4680 positive electrode plate length is 21700, but the coating length is increased by 5.8 times, thus making the battery have a higher energy density.
Currently, the main players in my country's coating machine market are Yinghe Technology, Jiatuo Intelligent (a subsidiary of Putailai), and Haoneng Technology (a subsidiary of Keheng Co., Ltd.).
Yinghe, Jiatuo and Haoneng's main products can all achieve continuous coating, among which Yinghe's width is the largest, reaching 1600mm; Haoneng Technology's fastest coating speed is 120m·min; the current mainstream products have density accuracy of about 1.0%, and the gap is small.
2.2. The competitive landscape of the winding machine is expected to be redistributed. The extreme ear cutting welding process requires high
winding process is to wind small strips of the anode sheet and the diaphragm into a bare cell. The winding machine belongs to the core of the middle-section equipment for lithium battery cell manufacturing.
winding machine winds the die-cut pole sheet into a lithium-ion battery cell. During the winding process, tension control accuracy, deviation correction ability, winding efficiency, etc. are all keys that affect the quality of the battery product.
4680 The new technology of the battery will put higher requirements on the winder.
winder current major competitors are Pioneer Intelligence, Yinghe Technology, and Liyuanheng. Pioneer Intelligent has developed a cylindrical all-pole ear battery cell automatic winding machine and has been successfully launched, with a first-mover advantage. Yinghe Technology successfully launched the 18ppm large cylindrical winding machine in February this year.
4680 The battery is cut directly on the empty foil to form the electrode, which puts forward higher laser cutting technology, speed, accuracy and quality requirements for high-speed filmmaking equipment.
Haimuxing high-speed laser chip machine equipment is a high-quality equipment for the lithium battery ear cutting.
company disclosed in its prospectus that in December 2019, the company received the first order from Tesla, a new energy vehicle giant, with a total order amount of US$11.05 million, mainly high-speed laser chipmakers.
Currently, Haimuxing has two high-speed laser chips, vertical and horizontal, both of which have the functions of single-sided or double-sided slicing ears of lithium batteries, and can produce 8 pole pieces at the same time.
equipment all adopt a single-sided large plate and cantilever-type support structure; it can completely replace traditional hardware die-cutting equipment; it has high speed, good consistency of processing products, and low cost of use.
In view of the fact that Haimuxing Pole Ear Cutting Technology has been deeply recognized by Tesla, the company is expected to participate in the industrial chain in this Tesla 4680 battery production.
In addition to the electrode cutting, the welding volume of 4680 battery electrode ear welding also increases due to the increase in the number of electrode ears.
battery cell welding middle process generally includes electrode welding (including pre-welding), electrode tape spot welding, battery cell entry pre-welding, housing top cover seal welding, liquid injection port seal welding, etc. The rear process includes connection sheet welding when battery PACK modules, and explosion-proof valve welding on the cover plate behind the module.
Among them, the cylindrical battery has two positive and negative electrode fluids welded to the battery cell, the electrode fluid has two connecting pieces welded to the bottom and the shell, the welding of the two end covers and the welding of the liquid injection holes, and the welding process is increased compared with that of the cylindrical battery size is smaller than the square shell battery, electric vehicles with the same power need to be equipped with several times the number of cylindrical batteries than the square shell battery, and more welding equipment is needed for processing.
In addition, the increase in the number of pole ears requires higher accuracy, quality and consistency of welding, new requirements for the stability of welding machines, and higher requirements for welding and seal reliability.
pole ear welding is currently usually used for welding using lasers.
laser device has the advantages of small footprint, no air and noise pollution in laser welding, low power consumption, high electro-optical conversion rate, low equipment loss, and self-adjustment of welding speed, welding depth, welding width, etc. It adapts to welding of different materials and products, achieves precise welding, more reliable quality and cleaner appearance.
Currently, the main manufacturers of laser welding in my country are Lianying Laser, Dazu Laser and Everbright Laser.
At present, Lianying Laser has publicly stated that it has laid out 4680 battery welding technology and is in prototype assembly and debugging.
Lianying disclosed in the 2021 interim report that the prototype design of the cylindrical battery assembly line has been completed, and the target matching meets the automated assembly and production of cylindrical batteries such as 21700, 32131, 4680, and is currently in the prototype assembly and debugging.
2.3. The kneading and flattening process has created new demands, and the process direction of the battery shell is still different. Because the number of full-elbow ears is large, directly assembling will cause the ears to fold, resulting in unevenness after winding. Therefore, the kneading process needs to ensure that the electrodes are flat.
The traditional kneading method has a great impact on the quality of the entire product and will also reduce the product's pass rate and safety performance.
The current traditional method of full-pole ear kneading is mainly to directly contact the full-pole ear through the kneading machine, and then as the flat head rotates, the full-pole ear is close to the full-pole ear, and the rotation drives the full-pole ear to flatten at the end of the winding battery cell.
In this method of kneading, since the kneading head directly contacts and rubs with the all-pole ear, the soft all-pole ear part will often be crushed, and the crushed pieces will enter the positive or negative ends of the cylindrical lithium battery and cause a short circuit.
Therefore, the development of the new all-pole ear kneading machine is expected to receive attention from the market. At present, Yifei Laser (proposed IPO) and Ningbo Dingxin (non-listed company) have conducted targeted research and development on the all-pole ear kneading process.
4680 The battery size is much larger than the 21700 battery, and it has new requirements for the battery case, and its process ushers in new challenges.
First of all, although the winding technology used by 4680 is relatively mature, the 4680 battery reduces the battery cell while increasing its size. Each battery cell has to withstand a greater current during charging and discharging, and generates more heat. The volume energy density after grouping is slightly lower, which puts forward higher requirements for the heat dissipation of the battery case;
Secondly, it is still doubtful to use the method of sealing the battery case. If the sealing is carried out by welding, due to the problem of low welding accuracy, secondary recoating and drying may be required, resulting in a decline in battery performance.
Ningbo Jingda: It was disclosed in the 2021 semi-annual report that the stretching equipment of steel shell 4680 has also completed prototype production.
Secondly, aluminium square shell stretching equipment designed in multi-link and servo modes have been launched on the market in batches around the battery shell production equipment for core parts of new energy vehicles.
The new generation of round shell stretching equipment is a continuous production line with cup punching machines and cam machines, which can achieve a production efficiency of 1,000 pieces per minute. The research and development will be completed in the second half of the year.
Slake: Developed a fully automatic battery case automation production line, and this kind of equipment is still blank in the country.
This production line has functions such as molding, cleaning, inspection, and packaging. Its production process is different from the equipment used in the existing domestic market. The battery steel shells produced have better consistency, higher production line efficiency, fewer personnel, and relatively low cost.
At the same time, Slake is preparing to introduce its new DWI production line (DWI, Draw Wall Ironing, is a core process unique to the can production line, which is the process of thinning and stretching the shell), further improving production efficiency and production accuracy. If DWI is used to produce battery shells in the future, it is expected to enhance its core competitiveness.
It is worth noting that the size of the 4680 battery case is very similar to the shape of the 330ml can, and there are certain similarities in the production process. Slake, as a can production equipment provider, has interoperability in technology.
Yawei Co., Ltd.: a leading company in metal forming machine tools, with a leading market share in domestic bending machines and stamping machine tools.
Company currently launches small tonnage servo press products to achieve small batch shipments. The domestic market size of servo press products is about 30 billion yuan, with a domestic penetration rate of less than 5%, and the penetration rate of foreign countries such as Japan has reached 90%. The servo press can effectively produce 4680 battery case. With the increase in the 4680 battery in the future, it will be the company's potential growth point in the future.
Kodali: has laid out 4680 battery shell business.
is a domestic supply leader in power battery precision structural parts, and has the ability to produce various components from battery round shells, composite columns, cover plates and other components. On November 8, Colida stated in an investor question and answer that the company has the technical accumulation of 4680 batteries and the ability to produce precision structural parts of various cylindrical batteries.
Zhenyu Technology: engaged in the research, development, design and production of precision stage stamping molds and precision structural parts.
has rich R&D, production experience and capabilities in precision structural parts of power lithium batteries. Deeply bound to the company's structural parts business. CATL has accounted for more than 90% of the business since its establishment.
3. Lithium battery companies are accelerating their layout of 4680, and mass production may be coming soon. Once it was launched, it has attracted the attention of the entire industry.
Currently entering the game includes lithium battery nobles including Panasonic, LG, and Yiwei Lithium Energy, as well as new players who are trying to overtake on the curve like Bick Battery.
4680 is in the infancy of technology, and mature production technology still needs to be continuously developed.
BIKE Battery: The first domestic battery company to launch 4680 full-length ear large cylindrical battery.
Bick Battery revealed in March 2021 that it is cooperating with many domestic and overseas customers to develop the application of full-length ear large cylindrical batteries. The 4680 battery cell samples are expected to be mass-off within the year.
00 million Lithium Energy:
November 6, 2021 announced that it will invest 20GWh large cylindrical battery production line and auxiliary facilities for passenger vehicles. The total amount of the large cylindrical battery production line and auxiliary facilities project is approximately RMB 3.2 billion (including value-added tax). After completion and production, it is expected to form a 20GWh/year large cylindrical battery production capacity for passenger vehicles.
Company signed an agreement with StoreDot in April 2021, and the two parties cooperated in three stages on electric vehicle 4680 batteries, valid until December 31, 2024.
In the first phase, the two parties will jointly develop and test sample for evaluation by StoreDot, Yiwei Lithium Energy and potential partners of electric vehicles;
will be produced in small batches in the second phase;
will be established in the third phase, and the products produced will be used in electric vehicles.
Currently, Yiwei Lithium Energy has laid out two large numbers: 46800 and 46950, and will gradually promote large cylindrical batteries after 2023.
JAC Motors:
In February 2021,JAC Motors and CBAK Energy Technology signed a three-year joint product development strategic agreement. CBAK Energy Technology will provide customized solutions for power batteries and battery packs in accordance with JAC's technical requirements, and the two parties will also jointly develop 4680 lithium batteries and battery packs.
The two parties will set up a joint R&D team to design, test and enhance the adaptability of their new products in the electric vehicle field. In addition, JAC has also promised to prioritize the use of battery and battery pack systems jointly developed by both parties in the future.
Panasonic:
10 On October 26, Panasonic showed its new 4680 battery trial product created for Tesla for the first time. Kazuo Tadanobu, head of Panasonic's battery division, said the new battery has five times the capacity of the previous smaller models.The battery is developed based on Tesla's demand, which Panasonic plans to supply it to Tesla and will begin "trial production" of the new 4680 battery at a factory in Japan in March 2022.
LG New Energy:
In March 2021, it said that it had begun to build a pilot production line for Tesla 4680 batteries, and some production lines were renovated at its Ochang factory. The assembly and plating equipment have been installed and is expected to start operations within the year as early as this year.
Its goal is to complete the pilot production line construction earlier than Panasonic, and plans to produce a brand new 4680 battery for Tesla in 2023. For this reason, factories are being considered in the United States and Europe to supply Tesla factories.
Samsung SDI:
April 2021 Foreign media reported that Samsung SDI and Hyundai are jointly developing the next generation of cylindrical batteries with a capacity greater than 2170 but less than 4680. Samsung SDI executives said it will officially launch within the next two to three years.
4. Industry target
4680 generally has little impact on the equipment, but it puts forward higher requirements on the performance of the main process equipment.
We believe that equipment companies with technical reserves are expected to gain a first-mover advantage and are expected to obtain high-share orders.
targets: high-quality lithium battery equipment companies such as Pioneer Intelligence, Liyuanheng, Hangke Technology, Yinghe Technology, Haimuxing, Lianying Laser; Other targets: battery shell structural parts and equipment companies such as Slake, Ningbo Jingda, Yawei Co., Ltd., Kedali, etc.
pilot intelligence: whole line and stand-alone faucet, 4680 has rich technical reserves, such as a winding machine suitable for all-pole ear cylindrical batteries.
Liyuanheng: power lithium battery equipment business has developed rapidly, laser die-cutting equipment, coating machines and other products have been successfully launched, and have been recognized by customers, with 4680 related technical reserves.
Hangke Technology: rear-road equipment leader, large cylindrical all-in-one machine and post-processing system have been produced and has been used for customer verification. The company is bound to overseas major manufacturers such as LG, and is expected to occupy a large market share after the 4680 battery production line.
Yinghe Technology: winding machine and other equipment have leading performance, and have launched products such as large cylindrical winding machine. It has in-depth cooperation with LG, Guoxuan and Yiwei, and is expected to benefit from the 4680 battery capacity in the future.
Haimuxing: the leader of high-speed laser chip machine equipment, leading in the cutting technology of the Wuji ear, has been well verified in Tesla 4680 batteries.
Lianying Laser: laser welding equipment faucet, layout 4680 battery welding technology, has been in prototype assembly and debugging. As the quantity and quality requirements of 4680 batteries have been greatly improved and the welding process has changed, the company is expected to benefit fully.
5. Risk warning
4680 Battery technology progress is lower than expected: the demand for new devices is expected to decrease.
downstream prosperity is lower than expected: it is expected to lead to a decrease in demand for batteries such as 4680, which will affect downstream enterprise equipment investment.
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