The most expensive part of an electric vehicle is the battery, and the most expensive part of the battery is the cells inside it. So the single most consequential decision an automaker makes about EVs is not styling or even range — it is whether to buy those cells from someone else or build them itself. GM's annual report answers that question directly.
In its Form 10-K for the year ended December 31, 2020, filed February 10, 2021, GM describes plans to "mass-produce battery cells for these and other future battery electric vehicles at Ultium Cells LLC," which the filing identifies as "an equally owned joint venture with LG." The document is on sec.gov; the filing was located through the EdgarBeast evidence index.
An "equally owned joint venture" is a specific structure, and the words matter. It means GM and its partner each put in capital, each share the risk, and neither fully controls the entity on its own. GM is not a customer buying cells at a price someone else sets; it is a co-owner of the factory that makes them. That is a far deeper commitment than a supply contract, and a far harder one to unwind.
Why take on that complexity? Control. If cell chemistry, cost and capacity are the levers that decide whether an EV is profitable, an automaker that merely buys cells has handed those levers to a supplier. By co-owning the cell plant, GM gets a seat at the table on cost-down roadmaps, chemistry choices, and how much capacity gets built and when. "Ultium" is the brand for the cells, the packs and the platform — and the JV is the industrial machine underneath the brand.
The trade-off is real. A joint venture means shared decision-making, shared profits, and capital that GM must put up alongside its partner's. It is slower to change course than a purchase order, and it ties two companies together for years. The filing's careful phrasing — "equally owned" — is exactly the kind of structural detail that decides who actually controls the most strategic asset in the business.
For a reader, Ultium is a case study in the make-or-buy question every automaker now faces. GM's 2020 10-K shows it choosing to make, through a 50/50 partnership that spreads the cost and the risk. Whether that bet pays off depends on execution no filing can guarantee — but the structure itself tells you GM decided that owning the cell was worth owning the complexity.