| GM BT1 platform | |
| Production: | 2021–present |
| Layout: | Dual- & triple-motor, all-wheel-drive |
The GM BT1 platform, marketed under Ultium branding, is a dedicated electric vehicle architecture or platform developed by General Motors (GM). It underpins electric full-size pickup trucks and SUVs sold by GM, using battery and motor technology developed under its Ultium program; these are shared with third-generation GM electric vehicles on the BEV3 platform. BT1 is categorized as a skateboard platform.
In October 2019, GM made an agreement with the United Auto Workers (UAW) union to invest US$3 billion in Detroit/Hamtramck Assembly over the next four years, renaming it to "Factory Zero" and converting it to a factory for electric trucks and vans.[1] The UAW's copy of the agreement revealed the "centerpiece" of the investment was a program internally called "Project O" or BT1, which would develop and begin selling a low-volume pickup truck by 2021, aimed at the high end of the market.[2]
The same platform developed for that project, which resulted in the GMC Hummer EV,[3] also would be used for electric versions of full-size General Motors pickup trucks (Chevrolet Silverado / GMC Sierra) and SUVs (Chevrolet Tahoe / Suburban, GMC Yukon, and Cadillac Escalade).
The BT1 platform is designed for full-size trucks and SUVs which currently use a body-on-frame architecture, while unibody passenger cars and crossover utility vehicles will be based on BEV3; both platforms use Ultium batteries and motors.[4] However, Nichole Kraatz, the GM chief engineer for battery electric trucks, characterized BT1 as "not a unibody and ... not a body-on-frame", as the body has an integral floor, like a unibody, but rests on the battery structure, which also acts as a structural member.[5] This confirmed early speculation published in 2019.[6]
Despite its name suggesting a relation to the T1 platform,[7] BT1 shares no parts with the older internal combustion engine full-size pickup truck and SUV platform.[8]
As implemented for the GMC Hummer EV, BT1 has a stamped and welded steel battery case with 24 modules, totaling 246 kW-hr gross, of which 212 kW-hr are usable; the total weight of the battery alone is .[9]