page_title: Toyota Prius
section_title: Batteries
hierarchical_section_title: Toyota Prius / Design and technology / Batteries
caption_attribution_description: English: High power Ni-MH Battery of Toyota NHW20 Prius 日本語: NHW20系トヨタ・プリウスの高出力ニッケル水素電池
context_page_description: The Toyota Prius is a full hybrid electric automobile developed and manufactured by Toyota since 1997. Initially offered as a 4-door sedan, it has been produced only as a 5-door liftback since 2003.
  In 2007, the United States Environmental Protection Agency and California Air Resources Board rated the Prius as among the cleanest vehicles sold in the United States, based on smog-forming emissions. The 2018 model year Prius Eco ranks as the second-most fuel efficient gasoline-powered car available in the US without plug-in capability, following the Hyundai Ioniq "Blue".
  The Prius first went on sale in Japan and other countries in 1997, and was available at all four Toyota Japan dealership chains, making it the first mass-produced hybrid vehicle. It was subsequently introduced worldwide in 2000. The Prius is sold in over 90 markets, with Japan and the United States being its largest markets. Global cumulative Prius liftback sales reached the milestone 1 million vehicle mark in May 2008, 2 million in September 2010, and passed the 3 million mark in June 2013.
context_section_description: There are two principal battery packs, the High Voltage (HV) battery, also known as the traction battery, and a 12 volt battery known as the Low Voltage (LV) battery. The traction battery of the first generation Prius update (2000 onwards) was a sealed 38-module nickel metal hydride (NiMH) battery pack providing 273.6 volt, 6.5 Ah capacity and weighing 53.3 kg (118 lb) and is supplied by Japan's Panasonic EV Energy Co. They are normally charged between 40–60% of maximum capacity to prolong battery life as well as allow headroom for regenerative braking. Each battery pack uses 10–15 kg (22–33 lb) of lanthanum, and each Prius electric motor contains 1 kg (2 lb) of neodymium; production of the car is described as "the biggest user of rare earths of any object in the world." The LV battery is essential to starting the car and providing initial power to the computer.
  The Second Generation Prius contains a 1.310 kWh battery, composed of 28 modules. Each battery module is made of 6 individual 1.2 V 6.5 Ah Prismatic NiMH cells in series forming a 7.2 V 6.5 Ah module with 46 Wh/kg energy density and 1.3 kW/kg output power density. Each module contains an integrated charge controller and relay. These modules are connected 28 in series to form a 201.6 V 6.5 Ah battery (traction battery), also known as the energy storage system. The computer-controlled charge controller and battery management computer systems keep this battery between 38% and 82% state of charge, with a tendency to keep the average state of charge around 60%. By shallow cycling the battery, only a small portion of its net available energy storage capacity is available for use (approximately 400 Wh) by the hybrid drive system, but the shallow computer-controlled cycling dramatically improves the cycle life, thermal management control, and net long term calendar life of the battery. Active cooling of this battery is achieved by a blower motor and air ducting, while passive thermal management was accomplished through the metal case design.
caption: Battery pack from the second generation Prius
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