Li-ion polymer

Hyundai Ioniq Hybrid / Kia Niro Hybrid 1.56 kWh Lithium-ion Polymer Battery

The Hyundai Ioniq Hybrid / Kia Niro Hybrid 1.56 kWh Lithium-ion Polymer Battery is the high voltage battery in the Hyundai Ioniq Hybrid (2017-2022), Kia Niro (Hybrid) (2017-2022).

At a Glance

Li-ion polymer chemistry
240 volts nominal

Specifications

Chemistry	Li-ion polymer
Nominal voltage	240 V
Capacity	6.5 Ah
Energy	1.56 kWh
Location	under the rear passenger seat
Weight	38.6 kg

Cars That Use It

Hyundai Ioniq Hybrid 2017-2022 AE; 32 kW motor, battery under rear seat Run the checklist
Kia Niro (Hybrid) 2017-2022 DE 1st gen; Kia spec 240V, 6.5 Ah, 1.56 kWh, 42 kW, 85 lb Run the checklist

What Goes Wrong

Reported failures, each from a source listed below, as of October 7, 2026.

Owner complaints NHTSA lists under the Hybrid Propulsion System component for the Hyundai Ioniq Hybrid, Kia Niro Hybrid, by model year: 2017: 2 · 2017: 7 · 2020: 1. These are all hybrid system complaints, owner reported and unverified, not only battery faults, as of 2026-10-07.

Symptoms

A keyword search of the 7 Hybrid Propulsion System complaints NHTSA lists for the 2017 Hyundai IONIQ HYBRID finds that 3 mention warning light, 4 mention stalling or shutting down (complaint text is owner-reported and unverified; as of 2026-10-07). (NHTSA complaints, 2017 Hyundai Ioniq+Hybrid, 2026-10-07)

Recalls

18V260000 2017 (Ioniq Hybrid) The hydraulic clutch actuator's inner oil seal may leak, letting oil collect in the cap area and possibly causing an electrical short.
18V704000 2017-2018 (Ioniq Hybrid) The main relay in the Power Relay Assembly may have poor connections between its contacts, raising electrical resistance.
22V459000 2017-2018 (Ioniq Hybrid) The Power Relay Assembly under the rear seat may overheat, on cars previously recalled under 18V-704.
18V666000 2017-2018 Kia Niro hybrid only: the main relay in the high voltage power relay assembly may have poor contact, raising electrical resistance.
22V836000 2017-2018 Kia Niro hybrid only: follow-up to 18V-666. The same main relay problem can overheat the area under the rear seats.

Check the exact car by VIN at nhtsa.gov/recalls.

Warranty

Hyundai's 2021 Warranty Coverage Guide lists lifetime battery coverage for the original owner of 2017-2019 Ioniq Hybrids (10 years/100,000 miles for later owners) and 10 years/100,000 miles for all owners from 2020 models, Hyundai's 2022 Owner's Handbook lists 10 years/100,000 miles, and Kia's 2017 and 2018 Niro Warranty and Consumer Information Manuals list the Hybrid Battery Pack under a 10-year/100,000-mile Hybrid System Warranty (10 years/150,000 miles for California-emission vehicles, excluding Pennsylvania and Washington); Niro 2019-2022 terms were not confirmed. (static.nhtsa.gov: INRD-PE21010-15928.pdf, 2026-10-07)

How battery warranties work.

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Sources

Last updated October 7, 2026. Failure and recall notes are as of that date. Spotted a mistake, or speaking for a maker? Report an error.

Hybrid Battery Test is independent. It is not affiliated with, sponsored by or endorsed by Hyundai, Kia. Names and part numbers are used only to identify the vehicle and the part.