While the two hybrid models are nearly identical, the battery-electric Ioniq has an enclosed nose for better aerodynamics.
The plug-in comes with an upgraded electric motor making 60 hp, compared to 43 in the hybrid. It uses the same 1.6-liter Atkinson-cycle four-cylinder, but Hyundai has to yet to divulge if the total system power in the plug-in is higher than the 139 horsepower figure for the hybrid. Using an 8.9 kWh battery, the plug-in is said to offer 50 km of electric range. The larger, heavier Ford Fusion Energi plug-in uses as 7.6 kWh battery and is rated at 32 km of electric range. On a loose estimate we'd guess the Ioniq plug-in will be rated around 40 km of electric driving.
As for the electric Ioniq, Hyundai is only giving us the numbers: 28 kWh battery, 118 horsepower, 103-mph top speed. Range is a quoted 250, but again we're not sure what cycle that's on. The 110-hp, 30 kWh Nissan leaf manages 172 km on the EPA sticker, so we expect similar (possibly lower) numbers from the Hyundai.
We still don't know when any version of the Ioniq will go on sale in the United States, but with confirmation that the related Kia Niro is still 11 months away we don't expect the Hyundai to be in showrooms before the end of the year.