Tesla's 4680 battery is difficult to mass produce!

On September 7, according to Electrek, Tesla encountered problems in increasing the mass production of its 4680 batteries , especially in terms of dry coating technology.

It is reported that the dry coating technology of the battery pack can eliminate most of the manufacturing steps, thereby reducing the cost of battery production. However, sources said that small-batch production of 4680 batteries can be achieved, but in large-scale production, the yield rate will have problems due to this technology.

4680 battery was launched two years ago

Two years ago, Musk revealed at Tesla's "Battery Day" that the company would launch a groundbreaking new battery unit to increase driving range and reduce production costs to support the mass production of pure electric products such as the Cybertruck pickup truck.

This is Tesla's 4680 cylindrical battery, which is planned to be mass-produced by the end of 2022.

At that time, the 4680 battery claimed that it could increase the range of electric vehicles by 54% and significantly reduce battery costs with its new designs such as tab-free and silicon-based negative electrodes, combined with CTC technology. This series of strong performance indicators attracted close attention from around the world.

Now, 4680 batteries have indeed been mass-produced, but only on a small scale. Model Y equipped with 4680 batteries has been delivered to users in the United States.

However, some users have found that the battery life of models equipped with 4680 batteries has not only not improved but has decreased...

Where does the problem occur?

Dry coating technology is difficult to break through

Some media stated that after interviewing 12 battery experts, they learned that because the "dry coating" process in battery cell production has been delayed in large-scale mass production, Tesla's 4680 battery cells have been in the small-scale production stage since they were put into production this year. As a result, only a small number of Tesla models can be delivered with 4680 batteries.

The reason is that a key to mass production of 4680 batteries is the dry-coating process. However, Tesla has encountered many challenges in promoting mass production of this process.

Stan Whittingham, co-inventor of lithium-ion batteries and one of the 2019 Nobel Prize winners, also told foreign media, “I think he (Musk) will eventually solve this problem, but not as fast as he planned because the process still needs some time to test.”

It is understood that when applying electrodes using traditional wet processes, battery manufacturers mix the materials with toxic binder solvents. Once the coating is completed, the electrodes are dried in large ovens, and the toxic solvents that evaporate during the process are recovered, processed and recycled, which increases costs.

In the dry coating process, the electrodes are applied using different adhesives and almost no liquid, so they do not need to be dried. This means it is cheaper, faster and less damaging to the environment.

Tesla has said that the process has helped Tesla reduce costs by one-third and cut factory floor space and energy consumption to one-tenth of the wet process.

But the reality is that the power batteries used in electric vehicles are larger and thinner, so it is difficult to mass-produce them using dry coating processes while ensuring quality.

"They can produce in small batches, but once they increase production they will encounter too many problems," commented an expert close to Tesla.

In addition, in addition to the difficulty in breaking through the dry coating technology, it is reported that industry problems such as silicon-based negative electrodes are also restricting the large-scale production of 4680 batteries.

The lack of technology may be one of the factors that prevent models equipped with 4680 batteries from improving their endurance...

Partially achieved

Although it is not possible to mass-produce at present, with the experience of small-scale production and after continuing to overcome difficulties, there is still a great possibility that the 4680 battery can be mass-produced. It just takes time.

Tesla is enjoying other improvements coming from 4680 battery technology.

For example, the number of welding points of Tesla batteries has been reduced from 17,600 to 1,660. Sources said that using older technology, Tesla needs about 4,400 cells to form a battery pack to power the Model Y, and 17,600 points need to be welded. The 4680 battery pack only needs 830 cells, which saves costs significantly.

The simpler design also means fewer connectors and other components, allowing Tesla to further save on labor costs and machine time.

Another source of efficiency is a stronger casing for the larger batteries. Tesla can now use adhesives to bond the cells into a rigid honeycomb battery pack, which is then attached directly to the Model Y's internal body structure.

Sources say this eliminates the intermediary step of bundling cells into larger modules, which are then installed in traditional battery packs…