Browse
Log in / Register
Share
March 26, 2026 — LG Energy Solution is producing prototype versions of a hybrid battery that packages pouch-cell internals inside a prismatic-style metal housing, a project co-developed with General Motors. Early samples are now being assembled at the company's Ochang complex in Cheongju, South Korea. The concept, code-named PtoP (Pouch to Prismatic), lets LG preserve its sprawling pouch-cell manufacturing base while answering automaker demand for prismatic form factors. GM has not yet signed off on a production vehicle application, but the project signals a significant strategic shift for both companies.
In the EV battery trade, form factor is a strategic commitment, not a cosmetic detail. Cylindrical cells are wound into metal cans. Pouch cells are flat, flexible, and sealed in foil laminate. Prismatic cells are rectangular blocks in rigid aluminum or steel housings. Each shape dictates how cells are cooled, how packs are assembled, and how much structural support the vehicle itself must provide. LG Energy Solution built its business — and its factory network — around pouch cells, a bet it made in parallel with fellow Korean battery maker SK On.
That bet has started to look less safe. Automakers, especially in Europe and China, are increasingly specifying prismatic cells because they simplify pack design and cut assembly labor. Industry forecasts suggest prismatic formats now claim roughly half of global EV battery demand and will keep gaining share. For LG, that creates an uncomfortable equation: invest billions to build prismatic lines from scratch, or find a way to make its existing pouch factories competitive in a prismatic world.
The stakes extend beyond cars. LG's pouch cells also anchor its energy storage systems (ESS) business, where prismatic cells have separately gained ground because their rigid blocks stack efficiently in large stationary racks. A hybrid PtoP product could serve both automotive and ESS customers, spreading development costs across two markets and giving the company a single platform to defend its installed base.
The answer, so far, is PtoP. According to industry sources who spoke in late October 2025, LG Energy Solution launched the Pouch-to-Prismatic program in the second half of last year and began investing in dedicated tooling early this year. Prototypes are now running on standalone equipment at Ochang Energy Plant 1. The machinery was supplied by System R&D, an automation partner closely tied to LG Electronics' Production Engineering Research Institute.
The engineering is a study in packaging discipline. A conventional prismatic cell starts with an electrode-and-separator stack lowered into a metal can, after which electrolyte is injected. PtoP reverses the sequence. Fully finished pouch cells — already filled, sealed, and quality-checked — are grouped two, three, or four at a time inside a two-piece metal cassette. The upper shell covers the top, front, and rear of the package; the lower shell protects the bottom and both sides. Once the two halves are welded together, the cassette behaves like a prismatic cell but contains the internal architecture LG has refined across a decade of pouch production.
The hardest step is joining the cells electrically. Each pouch cell terminates in thin metal leads that must carry current out of the package. In a PtoP cell, the leads from multiple pouches are gathered and welded to a busbar, which becomes the external terminal. Do that in a conventional module and welding robots have plenty of room to maneuver. Do it inside a compact metal cassette and precision becomes unforgiving. LG is using laser welding for these joints, and weld consistency is shaping up to be one of the biggest determinants of prototype yield and long-term reliability.
Cost drives the whole exercise. LG operates pouch-cell plants in the United States, South Korea, Poland, and other markets; converting any of those sites to prismatic production would mean stripping out entire lines and replacing them. PtoP allows the company to keep conventional pouch lines running and bolt on a smaller downstream packaging operation instead. The company argues the approach keeps manufacturing costs competitive and, over time, can lower total cost of ownership (TCO) for automakers that adopt it.
GM is the logical first partner. The two companies jointly own Ultium Cells, which operates large pouch-cell plants in Ohio, Tennessee, and Michigan. If GM validates PtoP, those facilities can keep feeding cells into a prismatic-compatible product line without a major re-tooling. That is an appealing scenario for a carmaker that has tempered its EV capital-spending pace while trying to close the cost gap with Chinese competitors. Still, an industry official said LG Energy Solution and GM are reviewing various potential applications and have not settled on putting the battery in a particular vehicle program.
Structural safety is part of the conversation, too. LG's pouch cells were at the center of the 2021 Chevrolet Bolt recall, which federal investigators traced to torn anode tabs and folded separators that could lead to fires. A rigid metal cassette adds a layer of mechanical protection: better crush resistance during handling, more stable geometry inside the battery pack, and an additional barrier between the cell and the surrounding vehicle structure. It cannot eliminate the root causes of a defective pouch cell, but it changes the calculus around how much physical abuse a cell can survive.
The packaging advantages extend to the vehicle itself. Pouch cells sit comfortably in wide, flat battery trays, but they become awkward when engineers want to stand cells on edge or route cooling channels through tight spaces. Prismatic cells, with standardized rectangular profiles, make cell-to-pack (CTP) layouts straightforward and make cell-to-chassis (CTC) integration feasible, as cells can serve as structural members rather than cargo. Both approaches are expected to anchor next-generation EV platforms, and a prismatic-style product is becoming close to a prerequisite for suppliers seeking a role in those programs.
SK On is working the same problem from the same starting point. At InterBattery 2026 earlier this month, SK On unveiled what it calls an "Integrated Pouch Prismatic Cell," a name that captures the industry's new willingness to blur format lines. Broad competitive pressure is making the urgency visible: CATL and BYD already manufacture prismatic cells at enormous scale, with cost curves that LG and SK On would struggle to match. That is why neither Korean company wants to surrender the segment without first attempting to adapt its existing tooling.
A reality check: automotive battery programs run on long timelines. A prototype in hand today is unlikely to reach series production before roughly 2030, and neither LG Energy Solution nor GM is bound by a formal schedule. The PtoP project could evolve, stall, or be overtaken by events if economics shift and prismatic investment becomes cheaper than retrofitting pouch lines. What is clear is that LG Energy Solution no longer treats pouch and prismatic as separate religions.
For the industry, the broader lesson is that battery form factors are becoming less fixed. The old debate — cylindrical versus pouch versus prismatic — is giving way to a more practical question: which company can squeeze the most value out of the assets it already owns. LG Energy Solution's PtoP experiment is an attempt to answer that question without betting the entire factory on one format. GM, as the prospective first customer, is watching closely to see whether the hybrid approach actually delivers.
