A wave of announcements on in-house battery development is sweeping through the automotive industry.

On September 4, Xiaomi unveiled its Longjia battery, anchored by two strategic partners, CALB and Sunwoda Power, which will be installed across all Xiaomi Pengcheng series models; on September 7, Li Auto (NASDAQ: LI) announced that its self-developed batteries will gradually equip its entire vehicle lineup; on September 16, Leapmotor declared at its technology day that its battery cells have achieved 100% in-house development; and on September 17, at the XPeng G9L launch event, He Xiaopeng stated bluntly that starting this year, all batteries would be made in-house.

Combined with BYD, Geely, GAC, and Changan, which have long established their own battery development systems, as well as overseas developments such as BMW's sixth-generation battery set to enter mass production in China, the signals of transformation in the power battery sector have become increasingly clear.

This wave was once simplistically interpreted as carmakers building their own factories and abandoning battery suppliers, but the current situation shows that the degree of self-development varies enormously among automakers, forming a clear technological hierarchy.

Essentially, what carmakers are competing for is not manufacturing capacity, but the right to define battery underlying solutions, material standards, system integration, and vehicle-level integration.

In other words, this is the beginning of supply chain restructuring.

In the second half of the new energy era, competition is no longer about who can buy better battery cells, but about who can define better batteries.

Why pursue in-house development?

As the heart-level component of new energy vehicles, power batteries not only account for 30% to 40% of the total cost of a new energy vehicle, but also serve as the core variable defining vehicle differentiation at the technical level.

Batteries are a very critical part of the electric energy strategy, said Ma Donghui, co-founder, president, and chief engineer of Li Auto (NASDAQ: LI). Without making batteries, one cannot speak of a true electric energy strategy. He noted that the cost of self-development is not lower than outsourcing, but regaining battery dominance is a continuation of Li Auto's long-term strategy and will determine the company's future direction.

For Li Auto (NASDAQ: LI), self-development means not just mastering a core technology, but more importantly achieving a triple integration from production to service, from battery to vehicle systems, and from after-sales to user experience.

One clear indicator is that Li Auto (NASDAQ: LI) has made a public commitment to all users that battery health will remain no less than 75% within 8 years or 160,000 kilometers.

This is also one of the important reasons why many carmakers choose self-development.

For example, in Xiaomi's Longjia battery definition standards, beyond implementing penetrating quality control management, the company also provides lifetime protection against power battery spontaneous combustion for first non-commercial owners, embedding brand credibility directly into battery quality commitments.

BMW's sixth-generation battery management is equally stringent.

It is reported that for the sixth-generation power battery, BMW has established an independent dedicated quality control chain.

All battery packs must pass BMW's globally unified functional and safety verification before leaving the factory, with data synchronized to a digital twin platform to achieve full lifecycle quality traceability.

Recently, BMW's Shenyang production base powertrain plant officially launched trial production of its energy intelligent control system, marking the localization of all core links of BMW's sixth-generation power battery in China, covering the entire chain from research and development, battery cell manufacturing, battery pack assembly, to energy intelligent control system production.

The criticality of this system has already been validated with concrete numbers on Geely's Shen Dun Golden Brick battery.

Ren Xiangfei, chief engineering technology scientist of Geely Automobile Group, said in an interview that in 2025, Geely's self-developed and self-produced battery pack shipments reached 1.03 million units; in the first eight months of this year, shipments already reached 1.1 million units, and more importantly, battery safety recorded zero accidents.

This is rarely seen in the industry, because it involves not just battery technology itself, but the entire supply chain management and quality control system, which is also Geely's advantage.

From intelligent driving to intelligent cockpits, and further to electric drive and battery systems, the boundaries of carmakers' self-development are continuously extending upstream in the supply chain.

The deeper significance of supply chain control capability is about holding the core initiative in product definition, system validation, and quality control in one's own hands, breaking free from the constraints of standardized components.

Different paths, same direction

Under this wave of self-development, the concept of self-development differs among carmakers, and the degree of difference determines each company's supply chain bargaining power.

When He Xiaopeng said batteries would be made in-house, he was referring to the self-development and self-manufacturing of battery packs, covering core aspects such as BMS battery management systems, thermal management, structural design, and pack assembly, while battery cells would still be supplied by external vendors.

Xiaomi's Longjia battery self-development philosophy is that Xiaomi handles battery product definition, leads battery pack design and development, participates in battery cell material, formula, and process development, and implements full-process quality control; CALB and Sunwoda develop customized electrochemical systems and materials based on Xiaomi's definitions and manufacture specialized battery cells.

Li Auto (NASDAQ: LI) has also chosen self-development and self-manufacturing for battery packs, with battery cells developed in-house and manufactured through contract manufacturing.

Ma Donghui stated that battery packs are highly coupled with the vehicle's chassis system, drive system, and overall architecture design, and data integration needs to be carried and threaded through by the battery pack. For battery cells, the approach is to develop in-house chemical systems and structural designs while entrusting battery companies with manufacturing, leveraging both sides' strengths.

Leapmotor, meanwhile, has achieved 100% in-house development of battery cells.

Recently, Leapmotor's self-developed battery cell production line has gone into operation, using lithium iron phosphate and winding processes, with initial capacity sufficient to supply 500,000 to 600,000 vehicles.

For many years, Leapmotor had been independently developing BMS, battery packs, and CTC chassis integration technology, while the most core battery cells were supplied by external vendors such as CATL and CALB.

Now, this boundary has been breached upstream into battery cell manufacturing for the first time.

As Ma Donghui put it, self-development with self-manufacturing and self-development with contract manufacturing are not a simple binary opposition.

Ren Xiangfei also stated that Geely's socialized collaboration will not stop, nor will self-development and self-production.

Previously, SAIC, GAC, FAW, Dongfeng, and Changan all chose to establish joint ventures with CATL, taking another supply chain collaboration path.

Moreover, as vehicle competition intensifies, charging infrastructure is no longer a moat for a single brand.

Geely Holding and NIO announced on September 28 a comprehensive strategic cooperation in the charging and battery swap sector.

The two sides, using capital as a纽带, jointly invest in each other's charging and battery swap business entities, share charging and battery swap technologies and standards, and co-build a nationwide integrated charging and battery swap service network, attempting to create a new model of open collaboration and multi-party win-win in the automotive industry.

Different models correspond to different levels of control that carmakers want over battery technology, and also correspond to completely different capital investments, risks, and long-term returns.

Carmakers developing batteries in-house has never been a single-choice question of either full self-development or pure procurement.

And most importantly, these innovative technologies and AI application capabilities are systematic work that must be done solidly, while also truly solving the problems encountered, before they can be brought to market. The market cannot be turned into a testing ground, said Gan Jiayue, CEO of Geely Automobile Group. Everyone has always emphasized that there are no instant cars, and we say there can be no instant technologies either. We must truly solve problems from the underlying logic.