Samsung SDI said it will invest a combined 25 trillion won (about $16.3 billion) in its plants in Ulsan and Cheonan to build out next-generation battery production, dividing the work so that one site invents the technology and the other scales it.

In a regulatory filing, the company said it would put about 16 trillion won ($10.5 billion) into the Ulsan plant, as reported by Herald Economy, a day after announcing a 9 trillion won ($5.88 billion) investment in Cheonan. Both programs run through 2040.

Two Plants, Two Jobs

The split is the point. The Ulsan plant will host mass-production lines for all-solid-state batteries, lithium iron phosphate (LFP) batteries for energy storage systems and sodium batteries, developing it into a hub for next-generation battery manufacturing. The Cheonan plant, by contrast, will house a “mother line” for validating next-generation battery technologies along with research and development facilities, developing it into a global flagship, or mother, factory. Where Cheonan proves the technology and the process out, Ulsan is built to make it at volume.

Samsung SDI is targeting mass production of all-solid-state batteries — widely seen as a potential breakthrough over conventional lithium-ion cells — in the second half of 2027, and CEO Noh Tae-moon said the company aims to achieve the world’s first all-solid-state mass production at Ulsan. Both are ambitious targets rather than settled outcomes: all-solid-state timelines have slipped across the industry before. The company’s current pilot line, known as the S-Line, sits inside its research institute in Suwon, south of Seoul, and covers about 6,500 square meters (roughly 70,000 square feet). Cheonan, meanwhile, already runs a dry-electrode pilot line called DryEV, aimed at improving on the cost structure of conventional wet-process electrode manufacturing.

What “Next-Generation” Actually Means

Four technologies run through the plan, each solving a different problem. All-solid-state batteries replace the flammable liquid electrolyte in a conventional lithium-ion cell with a solid one; in principle that packs more energy into the same space and reduces fire risk, which is why they’re widely seen as the potential successor to today’s cells — but the solid interfaces are hard to manufacture at scale, which is exactly why mass production is still a target. LFP, or lithium iron phosphate, goes the other way: it accepts lower energy density in exchange for lower cost, longer life and better safety, which makes it well-suited to stationary energy-storage systems rather than range-sensitive electric vehicles.

Sodium batteries swap lithium for sodium, one of the most abundant and inexpensive elements on Earth, trading some energy density for cost and supply-chain security. And dry-electrode manufacturing — the focus of Cheonan’s DryEV pilot — makes a battery’s electrodes without the liquid solvents and the energy-hungry drying ovens that conventional “wet” processing requires, aiming to cut both cost and energy use. The chemistries map onto different markets: all-solid-state for EVs and even humanoid robots, LFP and sodium for the energy-storage systems whose demand is being driven up by AI data centers.

Part of a Record Group Push

The battery investments are one piece of a much larger Samsung program. The group said it would invest a total of 2,655 trillion won domestically over the next decade — its largest-ever domestic plan — with the bulk, some 2,030 trillion won, going to expand its semiconductor clusters at Pyeongtaek and Yongin in the greater Seoul area, and the remaining 625 trillion won spread across the Honam, Chungcheong and Yeongnam regions. Within that, Samsung Display plans to invest 67 trillion won in Asan, South Chungcheong Province, on next-generation smartphone and microdisplay production, while Samsung SDI’s Ulsan and Cheonan battery build-out anchors the group’s next-generation energy bet.

Frequently Asked Questions

How much is Samsung SDI investing in batteries?

Samsung SDI has announced a combined 25 trillion won (about $16.3 billion) investment across two Korean sites: roughly 16 trillion won in its Ulsan plant, disclosed in a regulatory filing, and 9 trillion won in its Cheonan plant, announced the day before. Both programs run through 2040. Ulsan is being developed as a mass-production base for next-generation batteries, while Cheonan becomes a research-and-development “mother factory” for validating new battery technologies.

When will Samsung SDI mass-produce solid-state batteries?

Samsung SDI is targeting the second half of 2027 for mass production of all-solid-state batteries, and its CEO has said the company aims to be the first in the world to reach mass production, at its Ulsan plant. These are company targets rather than guarantees; all-solid-state batteries are widely regarded as a potential breakthrough but have proven difficult to commercialize, and timelines across the industry have moved before.

What is an all-solid-state battery?

An all-solid-state battery replaces the liquid electrolyte used in a conventional lithium-ion cell with a solid material. Because the liquid electrolyte is flammable, using a solid one can improve safety, and the design can in principle store more energy in the same volume, which is why all-solid-state cells are seen as a potential successor to today’s lithium-ion batteries. The main obstacle is manufacturing: producing reliable solid interfaces at large scale is difficult, which is why the technology is still moving toward mass production rather than already there.

What is a dry-electrode battery?

Dry-electrode manufacturing is a way of making a battery’s electrodes without the liquid solvents and energy-intensive drying step that conventional “wet” electrode processing requires. By skipping those stages, it aims to lower both production cost and energy consumption. Samsung SDI runs a dry-electrode pilot line called DryEV at its Cheonan plant, part of the next-generation manufacturing work that site is being built to validate before the processes are scaled up for mass production elsewhere.