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.
History
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 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.[5] 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.[6] This confirmed early speculation published in 2019.[7]
Despite its name suggesting a relation to the T1 platform,[4] 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 2,800 lb (1,300 kg).[9]
^Cole, Craig (October 21, 2019). "An electric Hummer comeback? We discuss with an expert". Road/Show. CNet. Retrieved 25 September 2023. '[BT1] is significantly different from T1 ... They are designing it [BT1] from the ground up as an electric platform,' [Sam Fiorani] added, meaning it likely won't have a separate frame with steel rails, but neither will it be unibody, a construction method most frequently used with cars, where the structure is one integrated assembly. Instead, it could be 'a little of each.'
