Samsung SDI has been making batteries since before most EV companies existed. Founded in 1970 as a cathode ray tube manufacturer and pivoting to lithium-ion cells in 1998, the South Korean firm now supplies cylindrical and prismatic batteries to BMW, Audi, Mercedes-Benz, Stellantis, and GM -- a client list that reads like a premium automotive industry directory. Revenue was KRW 13.27 trillion (roughly $9.3 billion) in fiscal 2025, down about 20 percent year-over-year as the global EV slowdown hit battery suppliers across the board. But the company's energy storage system (ESS) business hit record quarterly revenue in Q4 2025, driven by more than $1 billion in US grid storage contracts. And its all-solid-state battery program, targeting mass production in 2027, is the technology bet the company has staked its next decade on. AI-generated image Samsung SDI's all-solid-state battery architecture targets 700 Wh/L energy density. Credit: AI-generated $9.3B 2025 Revenue 1970 Founded 3.3% Global EV Battery Share (2024) 2027 ASSB Mass Production Target Five Decades of Energy Storage Samsung SDI's origin story is a study in industrial pivots. The company launched in 1963 as Samsung-Sanyo Parts (later Samsung-NEC), manufacturing vacuum tubes and, subsequently, cathode ray tubes for televisions and monitors. By 1999, it rebranded as Samsung SDI Co., Ltd. -- "SDI" standing for Samsung Display Interface -- and began the shift toward display panels and electronic components. The battery pivot came with the lithium-ion boom. Samsung SDI produced its first cylindrical lithium-ion cell in 1998 and scaled rapidly through the 2000s as consumer electronics demand for lightweight, high-energy batteries exploded. Phones, laptops, and power tools all ran on Li-ion cells, and Samsung SDI became one of the three dominant global suppliers alongside Japan's Panasonic and later China's CATL and BYD. The transition to electric vehicle batteries was a natural extension but required a different kind of manufacturing and product design. EV packs demand far more capacity and durability than consumer electronics cells, and the safety requirements are categorically higher. Samsung SDI entered EV supply agreements with BMW in 2015 and has since expanded to Audi (Volkswagen Group), Mercedes-Benz, Hyundai, Lucid Motors, and Stellantis. Its joint venture with Stellantis, StarPlus Energy, broke ground on a $2.5 billion battery plant in Kokomo, Indiana in 2023. A second joint venture, Synergy Cells with General Motors, is in the pipeline. Battery Cell Formats Samsung SDI is one of the few major suppliers producing batteries in all three commercial cell formats: cylindrical (including the 21700 and newer 46-series cells used by automotive OEMs), prismatic, and pouch. This format flexibility gives it options that single-format suppliers lack. Product Portfolio: From Consumer Electronics to Grid Storage Samsung SDI's business divides into two segments: Energy Solutions and Electronic Materials . Energy Solutions is the growth engine and accounts for approximately 93 percent of total revenue. Electronic Materials -- semiconductor process materials and display chemicals -- is a smaller but consistently profitable segment that contributed positively even in the difficult 2025 fiscal year. Automotive Batteries The core automotive product is the prismatic battery cell, used in modules that BMW integrates into vehicles including the iX, i4, and 5 Series plug-in hybrid. Samsung SDI's prismatic cells use a nickel-manganese-cobalt (NMC) cathode chemistry that offers high energy density at the cost of some long-term cycle stability compared to the iron-phosphate (LFP) chemistry preferred by Chinese suppliers for lower-cost applications. The premium OEM focus is a deliberate positioning choice: BMW, Mercedes, and Audi pay more for cells, and their customers have different expectations than buyers of mass-market vehicles. Samsung SDI branded its prismatic EV cell lineup as PrismStack in 2025, and its ASSB line as SolidStack . The branding signals an intent to compete on product identity as the battery market matures and OEMs treat cell sourcing as a strategic decision rather than a commodity purchase. Energy Storage Systems The ESS business has become Samsung SDI's bright spot. Grid-scale storage demand in the United States accelerated sharply in 2024 and 2025 as utilities scrambled to add storage capacity alongside solar and wind installations. Samsung SDI secured more than $1 billion in US ESS supply contracts in late 2025, including at least one LFP prismatic cell deal exceeding KRW 1.5 trillion ($1 billion). ESS now uses lithium iron phosphate chemistry -- a different and lower-cost chemistry than the NMC cells used in premium EVs -- because grid applications prioritize cycle life and safety over energy density. AI-generated image Grid-scale ESS deployments are Samsung SDI's fastest-growing segment. Credit: AI-generated Small Batteries: Power Tools, Wearables, Power Banks Samsung SDI's original consumer battery business remains active and profitable in high-margin segments like premium power tools (Milwaukee Tool, Makita), medical devices, and wearables. These batteries use cylindrical cell formats and benefit from decades of manufacturing efficiency. While this segment does not drive the growth narrative, it generates consistent free cash flow and provides manufacturing utilization floor during EV demand slumps. The Solid-State Bet: SolidStack and the 2027 Target All-solid-state batteries replace the liquid electrolyte in conventional lithium-ion cells with a solid ionic conductor. The theoretical benefits are significant: higher energy density (Samsung SDI has demonstrated 700 Wh/L in lab conditions, versus roughly 700-800 Wh/L for the best current liquid-electrolyte cells at the pack level), better thermal stability (no flammable liquid to ignite), and potentially longer cycle life. The practical challenges -- manufacturing at scale, achieving consistent ionic contact between solid electrodes and solid electrolyte, and managing mechanical stress during charge/discharge -- have kept ASSB cells out of commercial vehicles despite years of industry promises. Samsung SDI completed its pilot production line, called the S-Line, in 2023. At InterBattery 2026, the company unveiled a pouch-type ASSB specifically designed for physical AI and humanoid robot applications -- a market signal that ASSB won't be limited to passenger vehicles. The company has signed an MOU with Hyundai and Kia for robot battery supply and is in joint validation testing with BMW and Colorado-based Solid Power, which supplies sulfide-based solid electrolyte to Samsung SDI under a 2022 JV agreement. Battery Type Energy Density Chemistry Key Application Status PrismStack NMC ~700 Wh/L NMC Premium EVs In production LFP Prismatic ~400 Wh/L LFP Grid ESS In production 46-Series Cylindrical ~750 Wh/L NMC/NCA EVs, power tools In production SolidStack ASSB (prismatic) 700+ Wh/L Solid electrolyte Premium EVs (800+ km range) Pilot (mass prod. 2027) SolidStack ASSB (pouch) High power/compact Solid electrolyte Robots, wearables Development (H2 2027) The 2027 mass production target for SolidStack is the most ambitious commitment Samsung SDI has made. Competitors including Toyota, QuantumScape, and Panasonic are targeting similar timelines, but the industry has consistently pushed ASSB production dates back. Samsung SDI is investing KRW 1.42 trillion (roughly $1 billion) in R&D annually -- about 10.7 percent of revenue -- to hit that target. The R&D intensity is high even by battery industry standards. Manufacturing Footprint: Korea, US, Hungary, China Samsung SDI operates cell manufacturing plants across five countries. South Korea has two plants (Cheonan and Ulsan) that serve as the primary production base for automotive and consumer batteries. Hungary hosts a large automotive battery plant in Göd that supplies BMW and other European OEMs direct