Tesla's so-called 4680 battery, often described as the company's heart, will be installed again in the Model Y, its main model, in a more powerful form.

In a January earnings release, Tesla said it had finally resolved the dry cathode process, which had been the biggest hurdle to mass production. It also said it has begun installing battery packs using the process in some Model Y vehicles. The 4680 battery, once dismissed due to production yield problems, has resurfaced.

The biggest stated rationale for the 4680 battery's return is technical completion. The 4680 battery is larger in volume than the existing 2170 battery, but adopting a dry electrode process was essential to maximise production efficiency.

Under existing wet battery manufacturing, battery materials must be mixed in liquid and coated, then dried in a huge oven the size of a soccer field. The process requires enormous energy and time. A fully dry manufacturing method can greatly reduce this complex process burden.

Tesla has already applied a dry process to anodes, but has relied on wet methods for cathodes, which are much more technically challenging. In the announcement, Tesla Vice President Bo Egleston (본 에글레스톤) said, "We succeeded in producing both cathodes and anodes with a dry process." Experts assess this as an innovative change that can cut manufacturing costs by up to 50 percent.

■ Tesla's choice: global trade war and tariff risks

Tesla's reason for bringing back its self-made 4680 battery despite having external battery suppliers such as CATL and LG Energy Solution is the increasingly complex international situation.

The U.S. government's Inflation Reduction Act and strong tariff policies on Chinese-made batteries are a major pressure on Tesla. It is hard to receive subsidy benefits if it relies on Chinese-made materials or batteries. Tesla is securing additional supply chains to respond to trade barriers and tariff risks. By putting batteries made at its Texas Gigafactory into the Model Y, it is calculating that it can build a "North America production fortress" that is not shaken by changes in the external environment.

■ Dry process… an 'intermediate gateway' to all-solid-state batteries

Many experts are focusing on the point that this success in the dry process does not simply stay with the current 4680 battery. All-solid-state batteries, with solid electrolytes, are very difficult to produce using existing wet processes due to material characteristics. There is an assessment that the dry process know-how Tesla secured this time could become a "cheat key" that allows Tesla to take the lead in the race to mass-produce all-solid-state batteries, which Samsung SDI and Toyota are seeking to lead.

The dry process allows thicker stacking of electrodes, which is theoretically advantageous for increasing energy density. This could in turn lead to improved driving range for the Model Y or better winter performance.

As Tesla speeds up its internalisation of batteries, its relationships with external partners are also being reset. As Tesla processes materials directly and internalises production, existing suppliers have been tasked with going beyond simple supply to joint development of next-generation technology or securing new customers.

The Model Y taking back in the 4680 battery cannot be seen as a simple part replacement. It should be seen as the result of Tesla's big strategy coming together: lowering manufacturing costs, breaking through tariff barriers and, above all, securing leadership in next-generation all-solid-state battery technology.

Now the market's interest is focused on what performance the Model Y made with the dry process will show on real roads. It remains to be seen whether a 4680 battery-based Model Y, with lower prices and improved performance, can raise Tesla's competitiveness by another step.

Making the dry electrode process work at scale, which is a major breakthrough in lithium battery production technology, was incredibly difficult. Congratulations to the @Tesla engineering, production and supply chain teams and our strategic partner suppliers for this excellent…