New Ultium battery system underpins GM’s electric-vehicle future
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Mockup of future GM electric truck propulsion system and single Ultium pack, as shown to media and analysts March 4, 2020. (GM) 

New Ultium battery system underpins GM’s EV future

Coming 11-vehicle EV portfolio will be supported by just 19 EV propulsion combinations.

General Motors on March 4 gave media, investors and key dealers the first look at the electric-vehicle (EV) onslaught it is readying for production, along with related propulsion, battery and charging technologies. Staged at the company’s Technical Center in Warren, Mich., with engineers and designers as presenters, GM’s unprecedented vehicle and technology unveiling was the largest single aggregation of new EVs any OEM has yet revealed at one time.  

The company revealed 11 battery-electric EVs, including CUVs and SUVs for Chevrolet, Buick and Cadillac; a long-wheelbase Cadillac “flagship” sedan; a Hummer EV pickup and SUV to be sold under the GMC brand and a Cruise self-driving shuttle. All were shown in late-prototype form under a “no photography” mandate. It was a powerful underscore of GM’s wide-scope plan to industrialize its battery-electric vehicle future.    

GM CEO Mary Barra told the media audience, including SAE’s Automotive Engineering, that the company will launch 20 new EVs globally by 2023—part of a $20B investment in EV and automated-driving engineering and technology by 2025. She reiterated GM’s aim to sell 1 million EVs per year in the U.S. and China by 2025. 

“GM is capitalizing for a large bandwidth of EV products across our portfolio, and our future EV program will be profitable in its first generation,” Barra promised. The company’s new lithium battery system, known as “Ultium,” along with its new “BET” modular vehicle architecture and its global scale will drive profitability, she asserted. The Ultium battery enters production in 2021, in the new Hummer EV pickup and SUV.  

Mark Reuss, GM’s president, noted that GM’s global patent portfolio for electrified technologies now exceeds 3,000 patents. In transitioning the company to an all-EV lineup, he stressed the bill-of-material and assembly-process benefits with the following example: GM currently has 555 different IC-engine powertrain combinations in production. The 11-vehicle EV portfolio on display will be supported by just 19 EV propulsion combinations using GM’s battery modules, drive units (based on a single traction-motor family) and power electronics, he said. 

New battery chemistry, configuration
Ultium was the technical highlight of GM’s showcase of “every [hardware] element to realize an all-electric future," according to Barra. The battery system combines advanced new cell chemistries, ‘smart’ modules that automatically calibrate for either pouch- or cylindrical-type cells and advanced power control and thermal management. The new chemistry features LG Chem’s NCMA (nickel-cobalt-manganese-aluminum) cathode. The nickel-rich (up to 90%) chemistry requires 70% less cobalt than current-gen NCM (nickel-cobalt-manganese) cells, explained Andy Oury, GM’s lead architect and strategy manager for high-voltage battery packs.  

NCMA is more energy-dense than the incumbent NCM, making for lighter and less-expensive batteries, Oury noted (GM expects battery costs to be reduced to less than the longstanding industry target of $100 per kilowatt-hour “early in the product cycle,” claimed Barra). The new NMCA chemistry also offers enhanced cycling and thermal stability, deemed vital for EV durability and safety. Meanwhile, GM has zero-cobalt and zero-nickel anodes in development, said Doug Parks, executive VP of global product development, as the company strives to markedly reduce batteries’ reliance on precious and semi-precious elements. Oury added the GM has “an eye toward sourcing as much of the [battery] material as possible in North America.”

Ultium’s battery modules are designed to accommodate either pouch- or cylindrical-form-factor cells, depending on the supply base in each market, Oury said. The cells can be oriented vertically or stacked horizontally for six, eight, 10 or more modules per pack in most of the new GM EVs. For the extreme duty-cycles required in trucks, the packs also can be double-stacked, in sandwich fashion, in the vehicle’s underfloor area. The latter will be the configuration in the Hummer EV and full-size pickup trucks.

Parks said the Hummer EV and pickup battery packs will feature up to 26 battery modules – a total of 200 kWh of available energy and as much as 400 miles (644 km) of driving range. That compares with 100 kWh in Teslas’s Model S and 135 kWh claimed by Rivian to be available in its upcoming R1T and R1S electric truck and SUV. Reuss said the new batteries, in tandem with as many as three propulsion motors on a single platform, can provide a range between 235 hp and 1000 hp, depending on configuration. Front-, rear- and all-wheel-drive layouts will be possible with the new motor family.

Oury said that the Ultium packs have 57% fewer high-voltage connections versus the 2019 Chevrolet Bolt EV pack. Engineers here confirmed Barra’s assertion that GM and battery-development partner LG Chem are making good progress in reducing battery-cell costs to below $100 per kWh. Last year, battery prices averaged $156 per kWh, according to BloombergNEF. 

Charging ahead
GM also has developed new charging technology. Most of the coming EVs will operate on 400V architectures with a charge rating of 200 kW, while the trucks will be capable of DC fast-charging at 800V and 350 kW. The system will continue to use the industry-standard SAE J1772-based CCS “combo” connector, which Parks said is “fine for the near term, but amperage requirements are increasing so we’ll have to keep an eye on that.”

Just prior to the EV technology and vehicle reveal, the company announced it is launching a corporate-wide effort to install some 3,500 new Level 2 (240-volt) charging points at GM facilities in the U.S. and Canada starting late this year. Recharging experts at GM said studies have revealed that EV purchase consideration increases sixfold if the potential buyer has access to workplace charging. “This is another step down the path to making EV ownership easier for everyone, especially for our own employees,” said Reuss in a release. “Charging infrastructure is crucial to wider acceptance of EVs, and we’ll continue to do everything we can to improve it, both for our employees and for all our customers. We encourage other companies to do likewise.”

According to Reuss, GM also has created a dedicated high-voltage battery safety team that is integrated into all future vehicle programs. Working with the structures and propulsion-system development teams, the battery-safety team focuses on solutions for protecting the battery in a crash “much like we protect fuel systems,” he said.  

Reuss noted that GM has “played key roles in standards committees through organizations like SAE around battery safety,” and intends to remain an industry leader” through this process. 

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