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The E-GMP platform is the Hyundai Motor Group’s first vehicle architecture dedicated to electric vehicles. (Hyundai)

Hyundai details first EV-dedicated vehicle architecture

The E-GMP platform is engineered for bi-directional charging and high-level automated driving.

The Hyundai Motor Group on December 1 revealed E-GMP, its first vehicle architecture dedicated  for electric vehicles (EVs). The E-GMP platform is oriented around a rear-wheel-drive layout and is designed for both  modularity  and production  scale. The E-GMP architecture will be the foundation for future EVs for the Hyundai, Kia and Genesis brands. The Group  projects selling 1 million EVs by 2025, when it will have 11 dedicated EV models.

The E-GMP architecture enters the market in 2021 with Hyundai’s Ioniq 5, followed by a Kia crossover and “a series of other models.” Like most other contemporary  EV platforms,  Hyundai’s E-GMP takes advantage of electric motors’ generally smaller size to create a platform with a RWD base configuration. Compact motor size and no requirement for a conventional longitudinal driveshaft enable easy configuration for all-wheel-drive applications.  

The platform’s general proportions were oriented toward a long wheelbase and short front and rear overhangs.  The company said in a release that E-GMP will be able to span a wide range of vehicle sizes, while the flat floor – now expected of most dedicated EVs – maximizes passenger space and allows a variety of potential seating configurations.

“Today our front-wheel-driven Hyundai and Kia BEVs are already among the most efficient ones in their segments,” said Albert Biermann, president and head of the R&D division for Hyundai Motor Group, in a release. “With our rear-wheel driven based E-GMP, we are extending our technological leadership into segments where customers demand excellent driving dynamics and outstanding efficiency.”

Dual-voltage charging
The E-GMP architecture features a dual-voltage charging system, claimed by Hyundai to be a first. The system’s standard design is for 800 volts, a capacity envisioned for maximum charging speed and efficiency and already in use by Porsche. But in a nod to the likelihood that 800-V charging infrastructure will take time to mature, the E-GMP charging system can operate at 400 volts without any adapters or extra components, internally stepping up 400-V input to 800 V.

Moreover, the system offers bi-directional energy-flow capability: an E-GMP vehicle can use battery power to feed up to 3.5 kW into a home’s electrical system – or even  charge another EV’s battery pack. Hyundai said a fully-charged battery can power a moderate-sized home air-conditioning unit and a television for up to 24 hours. The bi-directional capability is unique, but not a world-first: Nissan has for some time offered the feature for its seminal Leaf.

More directly, the adaptable charging system can recharge the E-GMP-equipped vehicle’s battery pack to 80% in 18 minutes at today’s increasingly-available DC fast-charging rates of 350 kW, the company said, or accept enough charge for 26 miles (100 km) of driving in about five minutes – a figure chosen likely for its approximation of the time it takes to refuel an internal-combustion vehicle. Currently, most production EVs can DC fast-charge at a maximum of about 150 kW.

Range game
Hyundai did not state a specific battery-pack capacity for an E-GMP vehicle, saying for now only that the pouch-type lithium-ion cells make for a pack that is 10% more energy dense “compared to existing EV battery technology,” and “will be the most power-dense system that Hyundai Motor Group has ever created.”

The most that Hyundai said about vehicle range – and, by extension, battery-pack capacity: “A BEV based on E-GMP is capable of a maximum range of over 500 km [311 miles] with a fully charged battery, according to the Worldwide Harmonized Light-duty vehicle Procedure (WLTP).” The company did say, however, that although the pouch cell design is a mainstay, the battery-pack modules can be specified in different quantities depending on vehicle type.

The E-GMP architecture includes a technology that is gaining momentum: a power inverter using silicon-carbide (SiC) semiconductors. The significantly more-efficient switching frequencies available with SiC typically means smaller, lighter and higher-speed traction motors can be used. In the case of  E-GMP, Hyundai said speeds for its permanent-magnet traction motors can be up to 70% higher than current drive motors.

“This motor can enhance system efficiency by around 2-3%, which means the vehicle can be driven for approximately 5% longer on the same battery energy,” the company noted. The E-GMP traction motors are combined with the inverter and a transmission into an integrated component. Hyundai did not yet provide specifics about the integrated transmission, but given the higher-speed motor, presumably the transmission is a single-speed design.

Another unique aspect of modularization is in the axle itself. Hyundai calls it the Integrated Drive Axle (IDA), as it integrates the wheel bearings with the drive shaft. The company said E-GMP represents the world’s first mass production of such a design.

Two distinct EV platform strategies
E-GMP will feature a battery-pack structure made of  high-strength steel surrounded by hot-stamped steel components for additional protection and rigidity. It is likely that aluminum, high-strength steels and other weight- and strength-optimizing materials are blended throughout the E-GMP structure.

The E-GMP platform specifies an independent rear suspension with five links, Hyundai confirmed. Although it did not directly discuss the front suspension, it appears to be a conventional strut-type arrangement. Hyundai said the E-GMP platform will be directed to more mid-priced and premium models, while it will continue to produce smaller EVs adapted from existing IC-vehicle platforms.

“E-GMP is the culmination of years of research and development and brings together our most cutting-edge technologies. Our BEV lineup will evolve and be strengthened by this innovative new platform,” said Fayez Abdul Rahman, senior  VP of the Group’s Vehicle Architecture Development Center.

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