Chinese sodium-ion battery matches Tesla on build quality, teardown finds
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- RWTH Aachen University researchers Christian Siebert and Moritz Schütte published an independent teardown of a sodium-ion cell from Hina — a Chinese Academy of Sciences spin-off whose commercial packs are rated around 165 Wh/kg — in Cell Reports Physical Science, finding cell-to-cell resistance varied by just 5.3% across 120 cells, on par with the best lithium cells on the market.
- Hina's cell uses a "tabless, double-aluminum current collector design" mirroring Tesla's 4680 architecture, making it the first commercially available sodium-ion battery to adopt the design.
- The teardown also flagged unexpectedly high and unevenly distributed copper in the cathode, which the researchers said "raises interesting questions about its role in performance and aging."
- The Hina cell still trails lithium-ion on energy density and cold-weather charging — researcher Schütte called low-temperature charging "a clear weakness" requiring thermal management, keeping sodium better suited to stationary storage and shorter-range or commercial vehicles.
- CATL is launching its Naxtra sodium-ion batteries in EVs in 2026, targeting ~175 Wh/kg and ~600 km of range with charging down to −30°C; in February, CATL and Changan unveiled the Changan Nevo A06, the world's first mass-produced sodium-ion EV.
Why it matters: The knock on sodium-ion has long been "promising chemistry stuck in not-quite-ready phase." This teardown shows Chinese manufacturing is already mature: 5.3% resistance variance across 120 cells is the kind of consistency that only comes from a mature production line. The remaining gaps — energy density and sub-zero charging — are engineering problems with clear roadmaps rather than fundamental barriers. If sodium closes the density gap the way LFP did, the cost math gets very hard for Western battery makers to ignore.
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