The 2021 Kia Niro Plug-in Hybrid has an 8.9 kWh battery. Kia used a lithium-ion polymer battery pack of that energy capacity across the 2021 Niro PHEV trim range.
The battery is much larger than the 1.56 kWh pack in the conventional 2021 Niro Hybrid. That extra capacity is what allows the plug-in model to accept energy from an external charger and travel on electricity for shorter trips before the gasoline engine becomes necessary. The PHEV combines the battery system with a 1.6-liter gasoline engine and a six-speed dual-clutch transmission.
The 8.9 kWh figure is the battery’s stated energy capacity, not the same thing as usable energy in every operating situation. Automakers typically reserve part of a traction battery to protect longevity and maintain performance, so the amount available to the driver can differ from the headline pack size.
Another frequent source of confusion is the newer second-generation Niro Plug-in Hybrid. That later model adopted a larger 11.1 kWh battery, while the first-generation 2021 Niro PHEV retained the 8.9 kWh specification. Thus, 11.1 kWh is associated with a newer Niro, not the 2021 vehicle in this question.