Electric cars

Better profits for electric vehicles through engineering

Better profits for electric vehicles through engineering

General Motors’ Ultium platform has been making headlines lately, so let’s dive deeper into what exactly this “platform” is all about. Reduced is a shared modular battery system powering a family of related motor/drive units under the watchful eye and tight control of an Ultifi software operating system running on the latest electrical architecture from GM’s Vehicle Intelligence Platform.

Ultium is not a “skateboard” per se, like the vehicles that are planned to be supported will use very different suspensions and frames suitable for their very different use cases. But what Ultium is really about (listen up if you’re a shareholder) is GM’s roadmap for cost-effectively electrifying its fleet by sharing expensive hardware as much as possible: battery cells and monitoring system, the essential engine architecture and the operating system. . This makes the invisible electrified foundations scalable across the entire product portfolio. Namely: GM is considering some 19 battery and motor combinations. Compare that with today’s staggering portfolio of 550 combustion powertrain combinations.

The Ultium battery

Cell design: The use of laptop-style cylindrical battery cells allowed Tesla to quickly divide in the market, but the Ultium battery uses large pocket-style cells (23.0 x 4.0 x 0.4 inches) that pack energy more densely than cylinders. They weigh about 3 pounds each, contain 0.37 kWh of energy, can be arranged vertically or horizontally to suit space requirements, and are typically grouped in 24-cell modules. This design is also meant to facilitate reuse and recycling.

Chemistry: The nickel-manganese-cobalt-aluminum chemistry reduces cobalt usage by 70% compared to the Bolt EV’s NMC formula (both are lithium-ion). The aluminum also strengthens the electrodes and helps prevent lithium spikes from forming during rapid charging, which can short out a battery. This extends the useful life of the battery and reduces worries about frequent DC fast charging. Second-generation lithium-metal batteries using a silicon-based electrolyte are being developed with SolidEnergy. They’re not quite solid state, but they promise to double the energy density of NMCA batteries at 60% of the cost of first-generation cells. And they’ll be backward compatible so owners of first-generation Ultium products can upgrade, thanks to…

Wireless Battery Management: GM will be the first to monitor battery cells wirelessly using the Bluetooth-like 2.4 GHz spectrum, reducing the cost, weight, complexity, warranty issues and space required to solder all those wired connections. . It continuously monitors battery health, sharing information with the cloud to detect potential issues with certain battery lots, use cases, etc. storage room.

Capacity and Range: With each 24-cell Ultium battery module good for 8.9kWh, expect to see six-module packs rated for 50kWh usable capacity in the smallest and lightest vehicles, and the mighty six-pack 200 kWh (usable) range-topping in the GMC Hummer EV. GMC rates the latter at 329 miles (it exceeds the weight limit for EPA testing), but lighter vehicles with the larger pack should exceed 400 miles, while the Cadillac Lyriq’s 100kWh pack will provide over 300 miles.

Voltage and load: Most Ultium batteries will operate at 400 volts, capable of DC fast charging up to 250 kW. However, the Hummer EV’s two 400-volt packs can be virtually wired in series to emulate an 800-volt system. while chargingwhich allows 350kW chargers to add 100 miles in 10 minutes.

Cost: Clever design, NCMA chemistry and vertically integrated manufacturing have brought pack-level costs down to nearly $100/kWh, a tenth of that of the 2010 Chevy Volt. This is crucial to making Ultium products profitable.

The Ultium engine family

At launch, three oil-cooled axial-flow motors (the traditional barrel-shaped ones, not the new pancake-style) are envisioned: two permanent-magnet machines rated up to 241 and 342 hp, and an AC induction good for 83 horsepower. The latter will be paired with one of the former to provide high-efficiency all-wheel drive, as it creates no electromagnetic drag when “freewheeling” that a permanent magnet motor does. It appears that the metal plates that stack to form the stator are shared, with the more powerful motors getting longer, their windings getting more “turns” and their rotors possibly using more shared permanent magnets. All can be built using common tooling, and all motors will be unitized with gearbox and inverter. Additionally, GM will employ a control strategy that fine-tunes input power every 10 milliseconds, increasing efficiency to nearly 97 percent and providing more precise control during stability control interventions.

The first wave of Ultium products will combine these three motors into five drive units: two of the larger motors coupled together for rear-wheel-drive high performance, as well as single-motor applications for each of the other three motors. (Heavy and light applications are considered for the largest motor, which brings us to five units.) The table below shows our best estimate of which vehicles use which drive unit(s).

Ulfi operating system

We have entered the era of the software-defined vehicle, and Ultium electric vehicles will form the tip of GM’s spear in this regard. They will share a version of the electronic architecture of GM’s Vehicle Intelligence Platform introduced in 2019, which provides lightning-fast processing power and a robust, cyber-secure cloud connection that enables over-the-air updates, communication vehicle-to-everything and e-commerce. — basically, it makes vehicles behave like smartphones. The user interface will be through the Ultifi operating system. And because it’s Linux-based, it’s easy for third-party vendors to develop apps that, if approved by GM, can run on Ultifi.

Ultifi is designed to do two things for General Motors: build customer loyalty and generate a new revenue stream. This will come from streaming content subscriptions, concierge services, and the sale of permanent upgrades or the rental of temporary features over the useful life of a vehicle (much longer than that of a combustion). Here are a few that are being considered for possible future deployment:

  • Vehicle authorization using driver-facing camera and facial recognition software
  • Auto close windows/roof based on local weather forecast links
  • Planetarium app using GPS location to indicate nearby star constellations on infotainment screen(s)
  • Gesundheit mode, which closes the windows and activates air recirculation when the pollen count is high
  • Nearby traffic monitoring for icy/slippery spots, potholes, obstacles, etc.
  • Improved powertrain and suspension settings for use during track days

Will Wall Street finally show GM some respect if it makes a legitimate profit on its Ultium line of electric vehicles – and does it do so in the absence of all the excess EV credits supporting Tesla’s balance sheets? Probably not, but a company can dream.

Potential GM Ultium Engine Combinations
GM Ultium family of five power units
permanent magnet AC induction
Vehicle type Hi-Perf Dual Motor RWD Hi-Perf FWD or RWD Car/SUV RWD Car/SUV AT Car/SUV AWD Assistance Exit*
Extreme All-Wheel Drive Performance (GMC Hummer EV3) X X 1,000 hp, 1,200 lb-ft
AWD Performance/Work (Chevy Silverado EV, GMC Hummer EV2 & Sierra EV, Cadillac Celestiq) X X 510-664 hp, 780 lb-ft
RWD Work (Silverado EV Work Truck, Brightdrop Vans) X 340 hp, 325 lb-ft
RWD Luxury/Performance (Cadillac Lyriq & Symboliq) X 340 hp, 325 lb-ft
Mid-Luxe AWD (Cadillac Lyriq & Symboliq, Buick Electra) X X 400 hp, 400 lb-ft
Mid-Luxe TA (Buick Electra, Cadillac Optiq) X 340 hp, 325 lb-ft
Mainstream AWD (Chevy Equinox, Blazer, Buick Entry) X X 300 hp, 300 lb-ft
TA mainstream (Chevy Equinox, Bolt/Trailblazer) X 241 hp, 230 lb-ft
*Estimates; peak output influenced by battery matching, market segment, range goals, etc.