The Toyota Prius PHV utilizes Toyota’s first-generation lithium-ion drive battery. Due to Lithium-ion’s high energy density, compactness and light weight, these batteries are a good choice for electric vehicles and will be the preferred battery type in most electric and plug-in electric in the near future.
The 2010 Prius has one nickel metal hydride main battery pack that weighs 110 pounds. The battery pack contains 168 individual 1.2 V cells wired in series with a nominal voltage of 201.6 V DC. The 2010 Prius PHV has three lithium-ion battery packs, one main and two additional packs (pack one and pack two) with a combined weight of 330 pounds. Each battery pack contains 96 individual 3.6 V cells wired in series with a nominal voltage of 345.6 V DC.
When the PHV is fully charged the two additional battery packs supply power to the electric motor. Pack one and pack two operate in tandem with main battery pack but only one at a time on the individual circuit. When pack one’s battery’s charge is depleted, it will disconnect from the circuit and pack two will engage and supply electrical energy to the drive line. When pack two has depleted it will disconnect from the circuit and the vehicle will operate like a regular hybrid. Pack one and pack two will not reengage in tandem with the main battery pack until the vehicle is plugged in and charged.
The Prius PHV’s larger HV battery assembly requires additional cooling. The vehicle is equipped with three battery-cooling blowers, one for each of the three battery packs. Each battery pack also has an exclusive intake air duct. One cooling blower cools the DC/DC converter.
Like all Toyota hybrids, the lithium-ion batteries are built to last for the life of the vehicle. This first-generation lithium battery has undergone more than three years of coordinated field testing in Japan, North America and Europe in a wide variety of climatic environments and driving conditions.