Shulou(Shulou.com)11/24 Report--

Tesla is proud of the 4680 battery, mass production has encountered a big problem! Even the Nobel laureate confirmed it.

Foreign media Reuters recently interviewed 12 battery experts and learned that because the "dry coating" process in cell production has been slow to put into large-scale mass production, Tesla's 4680 battery has been in small batch production since it was put into production this year, and only a small number of Tesla's models can be delivered with 4680 batteries.

And because the output is too small, the 4680 battery should have played a significant role in reducing the cost of the battery has also been a 50% discount.

With a number of new designs such as electrodeless ears and silicon-based negative electrodes, the 4680 battery attracted close attention around the world with a series of strong performance indicators when it was released in 2020. Tesla claims that with CTC technology, the battery life of electric vehicles can be increased by 54%, and battery costs can be greatly reduced.

Suddenly, this is simply an explosive technological breakthrough in the electric car industry, and it is the star of tomorrow.

But after nearly two years, the Model Y with 4680 batteries has been delivered to users in the United States, and it has been found that the battery life of these models has not improved but declined, and even the problem of mass production has not been solved yet.

So what are the problems encountered in the production of 4680 batteries? What technological innovations does it adopt, and what improvements can it bring to Tesla? Reuters answered these key questions after communicating with 12 experts who knew about Tesla 4680 battery technology.

Dry coating technology is difficult to break through. Mass production of 4680 batteries was blocked in September 2020, Tesla officially released the 4680 battery (battery cell) that attracted global attention at the Battery Day, and it was officially put into production this year, installed on the Model Y model produced by Tesla's Texas factory in the United States.

4680 cells displayed by ▲ Tesla

One of the keys to mass production of the battery is the dry coating process (dry-coating). However, experts revealed that Tesla encountered many challenges in promoting mass production of this process.

"I think he (Musk) will eventually solve this problem, but not as soon as he planned, because the process still takes some time to test," Stan Whittingham, co-inventor of lithium-ion batteries and one of the 2019 Nobel laureates, told foreign media.

When using a traditional wet process to apply the electrode, the battery manufacturer mixes the material with a toxic adhesive solvent. Once the coating is completed, the electrode dries in a large oven, and the toxic solvents evaporated in the process are recovered, treated and recycled, all of which increase costs.

Production process of ▲ dry electrode

The dry coating process is different, in which electrodes are coated with different adhesives and almost no liquid, so they do not need to be dried. This means it is cheaper, faster and does less damage to the environment.

Tesla has said the process helped Tesla reduce costs by 1/3 and reduce the plant's footprint and energy consumption to 1/10 of the wet process.

In theory, the process is really fragrant, but in reality it is quite bony.

In 2019, Tesla bought Maxwell for $235 million by selling shares. The latter developed dry electrode technology and dry coating process for its supercapacitors.

It is understood that Maxwell's dry electrode technology and dry coating process can not only improve the battery life of electric vehicles, but also greatly simplify the manufacturing process, reduce manufacturing costs by 10 to 20 percent, and increase battery energy density by at least 20 to 30 percent.

Introduction of ▲ Maxwell dry electrode Technology

However, the power batteries used in electric vehicles are larger and thinner, so it is difficult to use dry coating process to carry out mass production under the condition of guaranteed quality.

"they can do small batch production, but once they increase production, they will encounter a lot of problems, too many." An expert close to Tesla commented to Reuters.

Experts say that because the output is too small, the cost savings that the process should have brought cannot be achieved at all.

Battery experts say the cost of the current 4680-battery Model Y can only be reduced by $2, 000 to $3, 000 (about 13956 to 20934 yuan). This figure is only half of what Tesla announced at the 4680 battery press conference.

And the savings of more than US $2,000 are mainly due to the fact that the battery is bigger.

▲ 4680 battery

Tesla used to use 4400 2170 cells to power the Model Y, meaning workers need to weld 17600 points (four solder joints for each battery) to assemble a battery pack.

If it is 4680, only 830 cores are needed, each core has only two solder joints, and the number of solder joints is reduced to 1660, the cost is significantly reduced. And the simpler design also means fewer connectors and other components, which allows Tesla to further save labor costs and machine time.

If the dry coating process could be mass-produced, it would reduce the cost of the 4680 battery pack on Model Y by half the cost of $5000,500 (38379 yuan)-half that of the 2170 battery.

As early as February this year, foreign media autoevolution quoted a blogger as saying that the quality rate of 4680 batteries at Tesla's California factory is still very low, which may affect the quality of the battery.

The document pictures released by the blogger at that time showed that there were 14 machines in operation that day, and the comprehensive quality rate of 4680 batteries reached 92%. One of the machines needs to be used to train staff at the Texas factory, so the defective rate of the battery is 82%.

Pictures of files posted by ▲ bloggers

Production data also show that the factory produced only about 6250 cells that day. A Model Y needs about 830 cells, which means the factory's capacity at that time was only about 7 Model Ys.

At the Tesla shareholders' meeting in August, Musk still announced that he would mass-produce 4680 batteries by the end of 2022. However, from the analysis of experts, this goal is obviously difficult to achieve.

There are no surprises for the continuation of the 4680 version of Model Y, mainly due to a reduction in costs in April this year. According to foreign media Drive Tesla Canada reports, Tesla sent an email to his employees, which showed that the standard continued version of Model Y produced in Texas starts at $59990 (about 381000 yuan).

It should be noted that the Model Y made at the Texas factory mentioned in the email is Tesla's first model with 4680 batteries. According to the revelations, the new car is a dual-motor version, with a range of 279mph and an acceleration time of 5.0s at 60mph, with a top speed of 217km / h.

A YouTube blogger named Spoken Reviews also bought a 4680 version of Model Y and evaluated it.

After testing, bloggers speculated that the Texas-made Model Y all-drive version could reach 230mph at an average speed of 75mph.

Instructions posted by ▲ bloggers

Through the comparison of the key parameters of the Chinese, American and European Tesla entry version of Model Y, it can be found that the battery life and acceleration of the 4680 version of Model Y have no obvious bright spot, which is not very different from the traditional 2170 battery.

▲ China, US and Europe Tesla entry version Model Y parameters comparison (the middle is the 4680 version of Model Y)

Tesla officially explained that the decline in the performance of the Model Y all-drive version after using 4680 batteries is to allow more people to drive Tesla Model Y. However, netizens do not buy it, thinking that Tesla is not to affect the sales of other versions of Model Y, but also want to reduce costs, not only face, but also Li Zi.

It looks good to release 4680 batteries in 2020. Interestingly, at Tesla Battery Day in September 2020, Musk is full of confidence in the 4680 battery and plans to achieve mass production this year.

At the time, Musk said that the energy of the 4680 cell increased five times and the output power increased six times. Coupled with CTC (cell directly into the chassis) technology, the new battery can improve the battery life of electric vehicles by 54% as a whole.

According to this data, this means that the long-range version of the Model 3 NEDC can be increased from 668km to more than 1000 km.

In order to achieve this goal, Tesla innovated the structure and material of the cell-- adopting a larger shape (diameter 46mm, height 80mm), eliminating the polar ear inside, replacing the carbon-based negative electrode with silicon-based material, and further reducing the content of cobalt in the positive electrode.

What Tesla needs to do is not just to improve the performance of the battery. The above methods of improving structure, optimizing materials and assembly process also reduce the cost of the battery.

Coupled with the optimization of mineral mining and extraction processes, the improvement of cell manufacturing processes with automation equipment, and the development of battery recycling technology, Tesla also reduced the battery kilowatt-hour cost (that is, the price per kilowatt-hour) by 56 per cent.

▲ Tesla automatic cell production line

Of course, the new cell seemed beautiful at that time, but in fact, some of the technologies were still in the research stage, such as the silicon-based negative electrode is still a difficult problem in the industry. Therefore, the technology announced by Tesla this time is still far from mass production.

On this Battery Day, Musk also focused on the production of dry electrode technology.

In production, the electrode needs to be wet treated first, and then introduced into the dry electrode technology, the specific process is to press the powdered material into a film, and then dry electrode coating, the process of this process is also more complicated. Tesla had not yet achieved mass production at that time. But the advantage is that after adopting this technology, the difficulty of battery production and operation is also reduced by 10 times.

Production process of ▲ dry electrode

Musk also talked about the assembly of the 4680 battery at the time, saying that just as the structural fuel tank of the aircraft was in the wing, Tesla's battery would be installed directly into the chassis and become part of the vehicle chassis (CTC technology).

The first step of this technology is to use the advanced all-in-one stamping technology to make the car body, and then install the electric core into the middle of the vehicle. Tesla said that this assembly process can save 370 body parts and reduce body weight by 10% while keeping the capacity unchanged. At the same time, the battery is closer to the center of the body, which can better balance the body and improve stability.

▲ Tesla 4680 battery can be loaded directly into the chassis

Musk also said on Twitter a few days ago that a new generation of batteries is not expected to be mass produced until 2022, and that the cells will be mainly used in Semi trucks, Mars pick-up trucks and the new generation of Roadster sports cars. At the time, he did not disclose that the new cell would be used in Model Y, perhaps he was worried about the production capacity of the new cell at the time.

▲ Musk said at the time that mass production would not be available until 2022 or later.

Battery companies are following, and domestic players are one step ahead. It is understood that 4680 battery production lines from battery suppliers such as Panasonic, LG and Samsung are gradually being rolled out, and domestic battery manufacturers are also laying out in advance on the track for fear of being left behind.

In February this year, according to foreign media CleanTechnica, Panasonic is renovating plant equipment and will trial-produce 4680 batteries. Panasonic also said at the time that if the 4680 battery could be delivered, it would first supply Tesla. However, Panasonic may not be able to mass produce 4680 batteries until next year, and the production line is currently under construction.

Comparison between ▲ 4680 battery and previous battery

In June this year, LG also announced that it would invest 580 billion won (3.8 billion yuan) to build a 4680 battery production line, but it will also be put into production next year.

When the eyes of foreign media are only focused on overseas battery giants, they often ignore the fact that some Chinese companies have already come up with 4680 batteries.

And Chinese enterprises are probably the first to come up with 4680 batteries in China. On March 19, 2021, China International Battery Technology Exhibition (CIBF 2021) opened in Shenzhen. Bick batteries carried a variety of battery specifications, including 4680 batteries.

Three executives of ▲ Bick Battery unveiled at CIBF 2021 with a variety of batteries, including 4680 batteries.

Li Dan, vice president of Bick Battery, revealed in an interview that the 4 series (diameter 46mm cell products) are mainly customized products, and customers can jointly develop with Bic battery to determine the specific parameters of the battery, while a non-customized mass production version will be available by the end of 2022.

At the 2021 Shanghai Auto Show, Yiwei LiNeng also brought its 4680 battery to the booth.

Ji Yajuan, director of Yiwei Lithium Energy basic Materials and Technology Research Office, said in an interview that Yiwei Lithium Energy is equipped with 46800 and 46950 large cylindrical batteries. The company will gradually market large cylindrical batteries after 2023, and it is expected that the annual production capacity will reach 20G who will reach 40GWh in 2024 by 2023.

▲ Yiwei lithium energy 4680 battery exhibit

Also with 4680 battery exhibits at the Shanghai Auto Show also powerful god battery. However, the car could not find more information about the Lishen 4680 battery, just found the photos taken by other media at the scene.

In any case, three Chinese companies have taken part in large-scale exhibitions with 4680 finished batteries. Moreover, there may be more companies to join in the future.

Conclusion: the release of new technology is easy to mass production, but it is difficult to recall Tesla Battery Day in 2020. Musk took out the 4680 battery and won all kinds of applause with new technology that no other players had. And the eye-catching numbers on PPT remind viewers that the new battery is very powerful and revolutionary.

But two years have passed in the blink of an eye, the performance of the model with 4680 battery has not surprised people, people seem to gradually forget the existence of this battery, and Tesla is silently solving the problem of mass production, which is hard to avoid.

Seeing the current situation, one can clearly come to the conclusion that any new technology is easy to release and difficult to mass produce.

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