Sodium-ion batteries now have a product launch and a delivery clock. CATL unveiled TENER Sodium in Munich on June 22, calling it a real-world validated sodium-ion energy storage system. The company says China deliveries begin in September, cumulative shipments should reach 1 GWh by the end of 2026 , and global deliveries start in June 2027. That changes the story again. CATL's 60 GWh HyperStrong agreement and 40 GWh Fujian expansion plan already gave sodium-ion scale. TENER Sodium adds a system architecture, export timeline, and project-design case. Storage buyers can now judge sodium-ion against customer deliveries, modular deployment, hard-carbon cost declines, hybrid lithium-sodium projects, and field performance instead of treating it as a conference-stage product. That changes how this technology should be understood in 2026. The question is not whether sodium-ion can replace lithium-ion everywhere. It cannot. The real question is where it can be cheaper, safer, easier to source, and good enough to win. Grid storage is where that answer is getting clearer by the month. AI-generated image The sodium-ion story now revolves less around theory and more around deployment volume. June 26 Update CATL has now unveiled TENER Sodium, a modular sodium-ion BESS platform rated at more than 30 MWh per unit. The company says China deliveries begin in September, cumulative shipments should reach 1 GWh by year-end 2026, and international deliveries are scheduled for June 2027. What Changed Since This Article First Ran When we first refreshed this explainer, the most important sodium-ion milestones were commercial: CATL had pushed Naxtra into mass production, Changan had put the chemistry into the Nevo A06 passenger EV, and BYD had shown sodium-ion was advancing on cycle life. Those were important proof points. The new development is scale. CATL's late-April agreement with HyperStrong covers 60 GWh over three years , which is large enough to change industry assumptions all by itself. Reuters called it CATL's first major sodium-ion energy storage deal. That matters because energy storage, not passenger EVs, is where sodium-ion can expand fastest without fighting head-on against nickel-rich lithium packs on energy density. Then came the U.S. side of the story. ESS, best known for iron flow systems, signed a letter of intent with Alsym to add 8.5 GWh of sodium-ion battery cells and modules to its own portfolio. That deal is smaller than CATL's, but strategically it may be even more revealing. It shows U.S. developers do not necessarily want one chemistry for every project. They want a menu. September Is the New Test The latest CATL timeline gives sodium-ion a near-term commercial checkpoint. The company expects initial energy storage deliveries in China in September, 1 GWh of cumulative shipments by year-end, and international deliveries beginning in June 2027. That is a different kind of proof than a product launch. By late 2026, integrators should be able to compare delivery reliability, installed cost, low-temperature performance, and early cycling behavior against LFP systems in real projects. By mid-2027, overseas buyers should know whether the same platform can clear certification, logistics, warranty, and bankability hurdles outside China. China's signal CATL and HyperStrong turned sodium-ion into a utility-scale procurement conversation. U.S. signal ESS and Alsym showed sodium-ion is also becoming a portfolio product for Western storage providers. Delivery signal CATL's September target moves sodium-ion from order-book story to customer-delivery test. Export signal TENER Sodium gives global buyers a June 2027 delivery marker. How Sodium-Ion Cells Work, and Why That Still Matters The electrochemistry has not changed. Sodium ions still shuttle between cathode and anode through an electrolyte, just as lithium ions do in lithium-ion cells. The catch is still the same too: sodium ions are larger and heavier, which makes it harder to match lithium-ion on gravimetric energy density. What has changed is the industry's willingness to work around that tradeoff. For stationary storage, being heavier is not a deal-breaker. Being cheap, safe, and easy to manufacture often matters more. Sodium-ion also keeps a structural manufacturing advantage because it can use aluminum current collectors and can be adapted to existing lithium battery production lines with less retooling than an entirely new chemistry would require. Key Differences from Lithium-Ion • Charge carrier: Sodium ions instead of lithium ions • Typical anode: Hard carbon instead of graphite • Current collectors: Aluminum can be used more broadly, trimming cost • Best fit: Cost-sensitive storage, cold-weather mobility, and frequent-cycling applications • Main weakness: Lower energy density in weight-sensitive vehicles CATL Has Moved the Conversation to Grid Storage At ESIE 2026 in Beijing, CATL unveiled a dedicated sodium-ion product for energy storage rather than treating the chemistry as a passenger-EV curiosity. The company said the new large-format cell is a 300+ Ah platform with around 160 Wh/kg energy density, 97% system energy conversion efficiency , and more than 15,000 cycles to 80% capacity retention. The detail that stood out most was not only the spec sheet. CATL built the product around the same enclosure dimensions as its 587 Ah lithium storage cell. That lowers switching friction for integrators, installers, and system designers. Utilities do not want a chemistry revolution that forces a full balance-of-system redesign if they can avoid it. Then the HyperStrong order arrived. Sixty gigawatt-hours is large enough to suggest CATL believes it has solved production, yield, and supply-chain problems well enough to promise big deliveries, not just conference demos. TENER Sodium turns that confidence into a system product. CATL says each modular unit delivers more than 30 MWh of rated capacity, weighs about 42 tonnes , and can be arranged so only 34 units are needed for a 1 GWh site. The system supports 1, 2, 4, 6, and 8 hour configurations, uses dedicated voltage regulation for sodium-ion's wider voltage range, and shares the same physical footprint as CATL's LFP storage platform. The May 9 capacity filing made that promise more concrete. CATL's Fuding Shidai subsidiary plans a 5 billion yuan, roughly $735 million buildout that would add 40 GWh of annual sodium-ion power-battery capacity. CATL now also cites a planned 160 GWh sodium-ion production base in Jining, Shandong. If those plans hold, sodium-ion is no longer waiting on a single factory to prove it can scale. Recent CATL sodium-ion signal Why it matters 300+ Ah storage cell launched at ESIE 2026 Shows a product designed specifically for BESS, not adapted from EV messaging 160 Wh/kg, 15,000+ cycles, -40 C to 70 C range Good enough on density, very strong on life and operating window 60 GWh HyperStrong deal The strongest proof yet that utilities and integrators will buy sodium-ion at industrial scale 40 GWh Fujian capacity expansion plan Connects the order book to a dedicated production ramp, with 24 months of new factory work planned September 2026 storage-system delivery target Creates a near-term field test for cost, reliability, integration, and customer acceptance TENER Sodium modular BESS Adds a 30 MWh-class unit, flexible durations, and LFP-platform compatibility June 2027 global deliveries Moves sodium-ion bankability from China-only delivery story to export-market test Why Utilities Like the Tradeoff In a stationary storage project, a battery does not need to power a sedan for 400 highway miles. It needs to cycle a lot, avoid fires, run through temperature swings, and land at a price that pencils out against lithium iron phosphate. Sodium-ion can be a strong answer there because weight barely matters while safety and materials sourcing matter a lot. This is also where sodium-ion's raw materials story keeps getting stronger. The chemistr