Toyota / Primearth EV Energy (Toyota-Panasonic JV)

Toyota Hybrid Gen4 NiMH

Nickel-metal hydride (NiMH) cells from Primearth EV Energy · 1.6 kWh total (0.8 kWh usable) · used in 4 model variants.

Toyota Hybrid Gen4 NiMH

Nickel-metal hydride (NiMH) · Primearth EV Energy · Compact pack under rear seat or trunk, air-cooled (cabin-fed)
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About the pack
Capacity
0.8 kWh
useable · 1.6 total
Service life
10 yr
150k mi typical
Warranty floor
see OEM warranty book

Pack overview

ChemistryNickel-metal hydride (NiMH)
Cell supplierPrimearth EV Energy
Cell formatPrismatic NiMH cells, modular pack
Voltage (nominal)244 V
CoolingAir (cabin-fed)
ArchitectureCompact pack under rear seat or trunk, air-cooled (cabin-fed)
Warranty10 yr / 150k mi

Known issues

Low
Highest-volume hybrid battery on the road. Real-world failure rates are very low through 150,000 miles. Many packs run past 200,000 miles with original cells.
Low
Failures cluster in extreme-heat climates (Phoenix, Las Vegas) and in vehicles with blocked rear-cabin air vents. Replacement cost has fallen significantly with aftermarket and refurbished options ($1,500-$3,000 typical).
Low
Inverter coolant pump on 2010-2015 Prius is the more common hybrid-related failure than the battery itself; ~$700 fix.
Low
NiMH chemistry tolerates partial-state-of-charge cycling far better than Li-ion. The trade-off is lower energy density and modest fuel-economy gains versus Gen5 Li-ion.

How this pack ages (industry context)

Industry fleet aggregates: 2.3% average annual capacity loss across 22,700 EVs / 21 models (Geotab, 2026), and 95% range retention at 5 years on average across 30,000+ vehicles (Recurrent, 2026).

OEM warranty floor on this pack: 10 yr / 150k mi.

Public per-pack degradation curves are not available for most models. Individual results vary materially with climate, charging behavior, and DC fast-charge frequency.

Vehicles using this pack

Battery-Related NHTSA Recalls

Recalls affecting battery, charging, electric propulsion, or thermal-event systems on vehicles using this pack. Recalls are deduplicated across model variants; affected vehicles are listed for each campaign.

19V491000 26/06/2019 HYBRID PROPULSION SYSTEM

Toyota Motor Engineering & Manufacturing (Toyota) is recalling certain 2018-2019 Prius C vehicles. The DC-DC converter may fail resulting in the auxiliary battery no longer receiving power from the converter, which may cause a loss of drive.

Consequence: A loss of drive increases the risk of crash.

Affects: Toyota Prius 2016-2022

20V369000 24/06/2020 HYBRID PROPULSION SYSTEM: INVERTER

Toyota Motor Engineering & Manufacturing (Toyota) is recalling certain 2013-2015 Prius and 2014-2017 Prius V vehicles not included in recall 18V-684. Excessive voltage in the Intelligent Power Module (IPM) within the inverter may cause the hybrid system to shut down, causing the vehicle to stall while being driven.

Consequence: An unexpected hybrid power system shut down may increase the risk of a crash.

Affects: Toyota Prius 2016-2022

21V734000 22/09/2021 ENGINE AND ENGINE COOLING:ENGINE:ENGINE CONTROL MODULE (ECU/ECM):SOFTWARE

Toyota Motor Engineering & Manufacturing (Toyota) is recalling certain 2022 Prius and Prius Prime vehicles. The Engine Control Unit (ECU) software may falsely detect an error and shut down the hybrid system, causing a loss of drive power.

Consequence: A loss of drive power increases the risk of a crash.

Affects: Toyota Prius 2016-2022

17V658000 18/10/2017 HYBRID PROPULSION SYSTEM: INVERTER

Toyota Motor Engineering & Manufacturing (Toyota) is recalling certain 2016 Prius vehicles. A capacitor within the hybrid system may not have been properly bolted to the inverter housing.

Consequence: If the capacitor was not properly secured, vibrations from driving the vehicle may damage the capacitor, shutting down the hybrid system, causing a loss of motive power and increasing the risk of a crash.

Affects: Toyota Prius 2016-2022

23V478000 12/07/2023 ELECTRICAL SYSTEM:PROPULSION SYSTEM:DC/DC CONVERTER

Toyota Motor Engineering & Manufacturing (Toyota) is recalling certain 2021-2022 RAV4 Prime and 2022 Lexus NX450h+ plug-in hybrid electric (PHEV) vehicles. The electric current rectifying module contained within the DC-DC converter may have been damaged during production, which can result in an electrical short-circuit.

Consequence: A short circuit can cause the DC-DC converter to overheat, increasing the risk of a vehicle fire.

Affects: Toyota RAV4 2019-2025

23V041000 02/02/2023 ELECTRICAL SYSTEM:PROPULSION SYSTEM:HYBRID MANAGEMENT:POWER CONTROL UNIT/MODULE (HPCU)

Toyota Motor Engineering & Manufacturing (Toyota) is recalling certain 2021 RAV4 Prime Plug-In Hybrid vehicles. During certain cold weather driving conditions, while driving in EV Mode, the hybrid vehicle control engine control unit (HEV ECU) software may cause the hybrid system to shut down if the accelerator is rapidly pressed to further accelerate the vehicle, resulting in a stall.

Consequence: An engine stall increases the risk of a crash.

Affects: Toyota RAV4 2019-2025

For TWD editorial coverage of major recall campaigns, see /recalls/.

Frequently Asked Questions

What chemistry is the Toyota Hybrid Gen4 NiMH?

The Toyota Hybrid Gen4 NiMH uses Nickel-metal hydride (NiMH) cells supplied by Primearth EV Energy. Cell format: Prismatic NiMH cells, modular pack. Pack architecture: Compact pack under rear seat or trunk, air-cooled (cabin-fed).

What is the warranty on this pack?

10 years or 150,000 miles. Specific terms vary by year and trim; check the manufacturer's warranty booklet for the exact vehicle.

How much does this pack degrade over time?

Industry-wide fleet aggregates show roughly 2.3% average annual capacity loss across 22,700 EVs (Geotab, 2026), with about 95% range retention at five years on average across Recurrent's 30,000+ vehicle fleet (2026). Public per-pack degradation curves are not available for most models. The Toyota Hybrid Gen4 NiMH battery warranty runs 10 years / 150,000 miles, which is the OEM-guaranteed minimum within that period. Individual results vary with climate, charging habits, and DC fast-charging frequency.

Which vehicles use the Toyota Hybrid Gen4 NiMH?

Toyota Prius 2016-2022 (4th gen (NiMH base, Li-ion AWD-e)); Toyota Camry 2018-2024 (Hybrid trim); Toyota RAV4 2019-2025 (Hybrid trim (RAV4 Prime PHEV uses different pack)); Toyota Highlander 2020-2025 (Hybrid trim).

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