Cadillac Lyriq: Inside GM’s Ultium Platform
The Cadillac Lyriq is one of the first vehicles to utilize GM’s Ultium platform, which will underpin all of its current and upcoming electric vehicles. After driving the Lyriq and being impressed, I decided to dig deeper into the details of its battery pack and the larger Ultium system. In an interview with Jerry Beemer, who leads GM’s EV Propulsion team, I learned everything there is to know about this innovative system down to the individual cells.
**Ultium Battery Cells**
The core of the Ultium platform is the Ultium battery cell, a 103Ah pouch utilizing a derivative of the nickel manganese cobalt (NMC) chemistry. This cell has a peak voltage of around 4.2V and a nominal voltage of around 3.6V. The upcoming Chevy Bolt will also be on the same platform but will use a lithium-iron-phosphate chemistry with different voltage parameters. GM’s Ultium system is defined not by the cell itself, but by key details such as the battery management system, pack construction, and communication between power electronics.
**Driving Voltage and Performance**
The Lyriq has 24 cells in each module, configured in an 8S 3P arrangement with a nominal module voltage of around 29V. This configuration allows for a 96S pack layout in the Lyriq. Lower voltage architecture has been a point of confidence for GM, and while higher drive voltages are a possibility, the automaker prioritizes driving down costs through volume production. Despite operating at 400V, the Hummer EV can provide a burst of 745 kW, showcasing the system’s power capabilities.
**Charging Capabilities**
The Lyriq can continuously charge at 190 kW from a station. GM is secretive about the voltage buffer of the Ultium cell for competitive reasons, but estimates suggest a peak charging voltage of around 393.6V. Regenerative braking allows the Lyriq to harvest up to 240 kW during braking. The potential for higher charge/discharge rates in a speculated Lyriq V performance version is exciting, as GM continues to explore the limits of its Ultium system.
**Future Innovation**
GM has not yet realized the full potential of its Ultium platform. As the automaker further delves into electrification, different configurations, beyond the 103Ah cell in an 8S 3P module, may be possible based on analytical and test data. This opens up possibilities for different cell formats like pouches, cylindrical cells, or prismatic cans in GM’s EV lineup. The future of electric vehicles is indeed an exciting time of innovation and potential growth.
In conclusion, GM’s Ultium platform and the Cadillac Lyriq showcase the automaker’s commitment to pushing the boundaries of electric vehicle technology. With a focus on efficiency, performance, and charging capabilities, GM is setting the stage for a new era of electrification in the automotive industry. The combination of innovative battery cells, module configurations, and optimized power delivery systems make the Ultium platform a promising foundation for GM’s electric vehicle lineup now and in the future.