GM has revealed that the recently launched Hummer EV will be the first vehicle in production with the company’s latest Ultium battery architecture. GM claims that the 24-module battery pack and three-motor drive system will provide the truck with best-in-class power output.
According to GMC, the batteries are unique because of their large-format, pouch-style cells, which can be stacked vertically or horizontally inside the battery pack. In the Hummer, two layers of vertical cell modules are used to produce a combined 24-module pack offering a GM-estimated range of 350+ miles. The pack’s low mounting position in the chassis, made possible by the cell architecture, also contributes to a low center of gravity, which should improve vehicle stability both on and off road, while also allowing for short front and rear overhangs.
The batteries use a nickel, cobalt, manganese, aluminum (NCMA) chemistry, which the company says has one of the highest nickel and lowest cobalt content of any large-format pouch cell; 70% less cobalt is used than GM’s previous generation of EVs. The Hummer will also be the first vehicle in GM’s line-up to feature its wireless battery management system.
The truck’s three electric drive motors yield a combined GM-estimated 1,000bhp, and when multiplied through the front and rear drive unit gear ratios, provide an estimated 11,500 lb-ft of torque at the wheels.
The single-motor front drive unit will have a 13.3:1 fixed-gear ratio and an electronic lockable differential, capable of delivering up to 100% of the motor torque to one wheel, in case traction is lost on the opposite wheel. All four wheels can be fully synchronized for true e4WD propulsion.
Two rear motors, contained in a single drive unit, independently power the rear wheels through a fixed gear ratio of 10.5:1, with the capability of varying torque output to each wheel. Motor output can also be synchronized to simulate a locking differential.
The vehicle will also be able to take advantage of 350kW DC fast chargers and the battery pack can be switched from its native 400V to 800V for charging. A disconnect unit and mechanical system within the pack enables the battery to switch from parallel to series connections, aiding fast charging.
GMC notes that the charging system is also designed to support legacy 400V charging infrastructure, without the need for a converter box or other accessories.