The trunk space in the IONIQ is optimized for cargo capacity, but depending on the version of the IONIQ you have, one, or both, of the ‘wings’ may be blocked off. The wings are the sections that extend to the left and/or right behind the rear wheel wells in the IONIQ trunk.
Trunk cargo space in the Hybrid is listed at 26.5 cubic feet, but is slightly less in the plug-in hybrid and ELECTRIC models at 23 cubic feet.
The Hybrid and plugin up until about September / October 2017 outside the US / Canada had a 12v lead acid battery in the boot / trunk. Since then it has had a 12v liPo battery in the main traction battery and a recharge button next to the fuel flap release in event of a flat 12v battery [src] – it’s unclear if this affects the cargo area at all.
Both Wings Full
The IONIQ Electric uses the trunk wings as a place to store parts of the traction battery, so trunk cargo space in the IONIQ EV is less than in the Hybrid and PHEV models.
Right Wing Full
This photo from Hyundai USA’s website of the IONIQ Hybrid shows the right wing blocked off and the left wing open/available for cargo.
IONIQ Plug-in vehicles without the optional subwoofer also have this configuration:
Left Wing Full
The WeatherTech website provides a photo that shows the IONIQ trunk with either nothing on the left and right, or the optional subwoofer on the left. However, there is no indication as to whether it is the IONIQ hybrid, or plug-in model, and no reports from the wild of IONIQ owners confirms this configuration.
Neither Wing Used
Just from comparing the photos above, it’s clear that the right side of the trunk space changes a little bit – some appear to have more of a blocked off space, while other IONIQs have a smaller hard plastic cover that appears to be an access panel – perhaps for the 12V supply battery on the earlier production models.
However, other than the image from the WeatherTech website asking if your IONIQ has the optional subwoofer, there is no indication that any IONIQs have the right wing space unused – it is either partially blocked off for the 12V batter, or completely blocked off for the EV traction battery.