Ultium

Ultium is an electric vehicle battery and motor architecture developed by General Motors. It is planned to be deployed for battery electric vehicles from General Motors portfolio brands along with vehicles from Honda and Acura.

Ultium is characterized by a modular layout, using pouch cells that can be stacked horizontally or vertically, depending on the form factor appropriate for each vehicle. A common charging and battery management system, Ultium Drive inverters, and a common series of motors are used across vehicles/types. Ultium is used by GM's BEV3 and BT1 platforms.

History

General Motors revealed the Ultium battery and platform technologies during a week-long March 2020 event held at the General Motors Technical Center in Warren, Michigan; GM chairman and CEO Mary Barra called it "a multi-brand, multi-segment EV strategy with economies of scale that rival our full-size truck business with much less complexity and even more flexibility". The Ultium Drive branding was applied six months later in September 2020, referring to electric vehicle drivetrain components exclusive of the batteries, such as the traction motors and power electronics.

GM announced in June 2021 it would collaborate with Wabtec to provide Ultium battery modules for zero-emission heavy-haul locomotives, including the FLXDrive.

In 2022, the US Army selected GM Defense to demonstrate an electric military vehicle, using the GMC Hummer EV pickup. In September, GM Defense was chosen to build a heavy-duty pack to power electric military vehicles.

Design

Ultium Drive

Ultium vehicles are powered by a family of five interchangeable drive units and three electric traction motors, known collectively as "Ultium Drive".

Planned motors include:

* A front-drive permanent magnet motor
* A front-drive or rear-drive permanent magnet motor
* A all-wheel drive assist induction motor

The motors are suitable for front-wheel drive, rear-wheel drive and all-wheel drive configurations. For example, the GMC Hummer EV prototype shown in March 2020 has full-time all-wheel drive and is equipped with three motors, one driving the front axle and the other two driving the rear wheels. The two drive units provide reduction ratios of 13.3:1 and 10.5:1 for the front and rear wheels, respectively. The three traction motor types are oil-cooled and share a common stator design.

The drive units are single-speed reduction gearboxes with integrated drivetrain electronic control modules that accept one or more traction motors and provide power to the wheels. These modules, sometimes called power electronics, include the traction power inverter, onboard charging module, and accessory power module; drive unit integration of these modules results in a combined mass that is half that of the equivalent components of the Chevrolet Bolt EV.

Ultium battery

Ultium battery cells feature nickel-cobalt-manganese-aluminum (NCMA) chemistry, and will be manufactured by Ultium Cells LLC, a joint-venture of GM and LG Energy Solution. Battery materials will be supplied by LG Chem and POSCO Chemical (cathode active materials) and Livent (lithium hydroxide).

Each Ultium pouch cell measures approximately and weighs , capable of storing 0.37 kWh; the nominal voltage is 3.7 V and its energy capacity is 103 Ah. The gravimetric energy density of each cell is ; the corresponding volumetric energy density is . Its gravimetric power density is 952 W10s/kg. Pouches may be oriented horizontally or vertically, affording packaging flexibility. 24 cells are combined into a module, and from 6 to 24 modules (144 to 576 cells) are combined into a pack with a capacity ranging from 50 to 200 kWh. GM claims that they can survive repeated DC fast charging.

For the GMC Hummer EV, two 12-module battery packs are wired in series, creating two 400 V, 100 kWh batteries; these batteries are stacked and wired in parallel, yielding 200 kWh storage capacity. The stacks can be temporarily switched to be wired in series, allowing for DC fast charging at up to 800 V and 350 kW.

Ultium features a wireless battery management system or wBMS, the first such architecture from any automaker. The wBMS was developed in partnership with Analog Devices and contributes to reduced battery costs, as it requires 90% less wiring and reduces volume by 15%.

Cost

In 2010, the cost of the 16 kWh battery in the Chevrolet Volt was estimated at per kilowatt-hour. With Ultium, GM estimates the cost will be reduced by 90% to approximately $100/kWh. This also is a significant reduction compared to the 60 kWh battery in the Chevrolet Bolt EV, which was priced at approximately $262/kWh in 2017, although GM had negotiated a significantly lower price of $145/kWh from its supplier, LG Chem. Part of the cost reduction results from the novel chemistry, which has 70% less cobalt than the Bolt's battery. In addition, labor costs are reduced because the wiring in each battery pack has been reduced by 88% compared to the Bolt due to the wireless battery management system.

Production

At least four production facilities were planned as of 2021:

* Ultium Cells LLC – Lordstown, Ohio, USA (Opened Sept. 2022, 35GWh capacity)
* Ultium Cells LLC – Spring Hill, Tennessee, USA (Opening late 2023, 50GWh capacity)
* Ultium Cells LLC – Lansing, Michigan, USA (Opening late-2024, 50GWh capacity)
* Unknown location, unknown opening date. Possibly New Carlisle, Indiana, USA.

GM also opened an Ultium Center factory in October 2021 in Shanghai, which produces batteries and traction motors for EVs produced and sold in China. In 2022, the United States Department of Energy (DOE) provided a $2.5 billion loan to Ultium Cells to assist in the construction of the three announced plants in the US. It is the first loan from DOE to a battery cell producer under the DOE's Advanced Technology Vehicles Manufacturing program.

Vehicles using Ultium

;Current
* GMC Hummer EV (2021–present)
* BrightDrop Zevo 600 (2021–present)
* Cadillac Lyriq (2022–present)

File:2022 GMC Hummer EV front.jpg, 2022 GMC Hummer EV
File:2022 BrightDrop EV600.jpg, 2022 BrightDrop Zevo 600
File:Cadillac Lyriq 001.jpg, 2022 Cadillac Lyriq

;Planned
* BrightDrop Zevo 400 (2023)
* Buick Electra E5 (2023)
* Chevrolet Silverado EV (2023)
* Chevrolet Equinox EV (2023)
* Chevrolet Blazer EV (2023)
* Cadillac Celestiq (late 2023)
* Honda Prologue (2024)
* GMC Sierra EV (2024)

See also

* General Motors BEV3 platform

References

{{General Motors

Electric vehicle platforms
General Motors platforms