Carmakers Are Branding Their Own EV Batteries. CATL's Manufacturing Moat Is Why the Market Splits.

A Li Auto i6 buyer in late July picked a battery brand from a two-supplier list that would not have existed a year earlier. The same car ships with either Sunwoda or CATL cells, and Li Auto added a two-year extended warranty on the Sunwoda pack to nudge buyers toward the newer supplier. More than half of the buyers still chose the CATL pack, according to 36Kr reporting.

That split purchase is the early evidence of a wave of carmaker-brand batteries rolling through China's EV market this summer. Xiaomi, Li Auto, NIO, and the Huawei-affiliated smart-car alliance have all launched or are about to launch batteries that carry the carmaker's own brand rather than the cell supplier's. The launch announcements pitch a carmaker-versus-CATL contest. The structure underneath is different: carmakers are reaching for the 30 percent of an EV's cost that the battery represents, and CATL's decade of high-volume manufacturing has built a moat the newcomers cannot replicate on a launch schedule.

The shift is visible in the spec sheets. Xiaomi's Longjia battery, formally launched on July 30, is rated for 2,000 charge cycles and a 500-joule bottom-impact standard chosen to survive rough roads and curb strikes. Li Auto's branded pack targets 75 percent battery health after 8 years or 160,000 kilometers. NIO has a 15-year cycle-life R&D program in motion. Huawei's smart-car alliance, sold under the Harmony Intelligent Mobility Alliance umbrella, markets a "Giant Whale" pack whose main pitch is thermal protection across the full temperature range.

These are not rebadged cells. Carmakers are defining the chemistry, the pack architecture, and the supplier audit chain down to the second tier. Industry sources told 36Kr the model is called "penetrating management" in Chinese industry shorthand: the automaker sets the technical and performance bar from cell to pack, partially shapes cell material choices, supervises core suppliers and production runs, and even sits in on interviews for core positions at the battery factory. The goal is supply-chain control and margin capture, not just branding.

The reason this matters is the cost share. A battery pack is roughly 30 percent of an EV's bill of materials, the single largest line item. Whoever controls that line controls the most important input price, the most important warranty exposure, and the most important safety recall surface. Carmakers are no longer willing to leave that line to a single supplier when the cells themselves are largely a commodity, and when the moat is concentrated in process rather than chemistry.

The moat is process. Industry engineers told 36Kr that CATL's competitive advantage is not a chemistry lead; it is the cell-to-cell consistency that comes from running the same production lines at scale for a decade. The shorthand one engineer used: "In China, the only cell maker that does not grade by tier is CATL, because all of their cells are the same." Same voltage curve, same internal resistance, same dimensions, batch after batch.

The physical consequence of inconsistency shows up in the battery management system, the BMS that runs every pack. Most BMS designs use passive balancing, which can only shed excess charge as heat. A pack designed for 100 kilowatt-hours of usable energy that contains one cell capable of holding only 98 will get clamped to 98, because the cheaper, more common BMS strategy cannot redistribute the gap. Active balancing can fill the valley, but it costs roughly ten times as much as the passive version, and at consumer-EV price points it is rare outside commercial fleets.

Cell mismatch is not just a range penalty. A pack degraded to 30 percent of its original capacity is still in service in many vehicles, and packs running on mismatched cells are more prone to overcharge and overdischarge at the weak cell, which raises fire risk. The failure mode applies across lithium chemistries, including the more thermally stable lithium iron phosphate, or LFP, packs that dominate China's entry-level market.

Carmakers believe they have an edge on the application layer. The BMS is software, and the carmaker knows the rest of the car, the thermal loop, the drive profile, the charging curve, in a way the cell supplier does not. Several industry sources told 36Kr that carmaker-tuned BMS algorithms may end up more efficient than the cell supplier's own, because the carmaker sees more of the system. Whether that holds depends on data scale and on the engineers writing the model.

The CATL counter-move is already running. 36Kr observed consumer-facing ads at airports, high-speed rail stations, and shopping malls that read, in Chinese, "When choosing an electric car, look at the battery; choose CATL." It is a slogan rather than a price cut, and it is aimed at the buyer who has not yet noticed that the battery on the options sheet now has a carmaker logo on it.

The market has already voted on coexistence, at least for now. The Li Auto i6 evidence is the clearest data point: same car, same warranty, two suppliers, and the majority of buyers still pick the incumbent. Xiaomi's Longjia launch and the wave of branded packs behind it will test whether that preference softens, or whether CATL's production consistency is the kind of moat that survives a decade of vertical-integration pressure. The next data point is the August sales cycle for the i6 and the first Longjia-equipped Xiaomi vehicles.