Electric Vehicle Battery Technology

Updated: Oct 18, 2020

Nickel Metal Hydride

Here at 1-Diagnostic we service a lot of Toyota Prius Generation 2 and Generation 3 models. The Rechargeable Electric battery modules of these models are the Nickel Metal Hydride (NiMH) battery type. NiMH batteries are advantageous for high-current-drain applications due to their low internal resistance making them an ideal battery choice for the first hybrid models.

Image 1: A single Toyota hybrid electric vehicle battery (6 cells)

A single Prius NiMH battery (pictured above) is made up of six individual NiMH cells, all of 1.2 Volts, which are combined in series, giving the battery a total voltage of 7.2 Volts. The Electric Battery in a Toyota Prius uses 28 of these individual batteries, thus overall producing a total voltage of 201.6 Volts (Image 2).

Image 2: A Toyota hybrid electric vehicle full NiMH battery pack (28 batteries)

Lithium Ion

Despite the widespread use of NiMH battery technology within Electric and Hybrid vehicles for the past 20 years, NiMH batteries now, for the most part, have been replaced by Lithium-ion batteries in new car releases. Companies such as TESLA use lithium-ion batteries to power their full-electric car models, whilst Toyota has been using Lithium ion battery technology in their Prius 4th generation Hybrid models, which were released in 2015.

Image 3: A Toyota hybrid electric vehicle full lithium-ion battery pack

Lithium ion batteries have a higher energy density, are more lightweight and have a higher voltage output than NiMH batteries. Therefore the battery can still achieve the same output voltage range as NiMH, whilst having the advantage of weight savings. Weight is an important factor in car design, the lighter a vehicle the more efficient it is. The Lithium ion Hybrid Prius battery pack has 207.2V, as opposed to the 201.6V of the NiMH version.

Other Future Technologies: Hydrogen Fuel Cells, Solar & Fluoride-Ion

Other technologies to power Hybrid and Electric vehicles are under constant development, with some of the most recent technologies to be used being Hydrogen Fuel Cells and Solar. Toyota have developed a hybrid plug in Prius, with a solar roof, enabling the electric battery to be topped up by the Sun’s rays whilst on the road.

Image 4: Solar roof on Prius

Toyota have also recently been reported to be working on a new type of battery technology, the fluoride ion battery. This would be used on their full electric car models in the future as an alternative to lithium-ion cells, which is the current battery of choice for most full electric vehicles. The fluoride ion technology is still in its early days however Toyota report it to have a range of up to 1000km, which Is further than the range provided by any current lithium ion battery technology.

Hydrogen fuel cells are another type of battery currently used to power full electric car models. Hydrogen cars are not as widespread and common on the roads as lithium ion powered cars, however they do exist, with some manufactures such as Toyota and Hyundai having Hydrogen powered models.



Image References

Image 1: Amazon 1-Diagnostic, (2020). Toyota Prius Hybrid Battery Cell - Replacement HYBRID Module Parts For Toyota Prius…[image] Available at:

Image 2: Ecomento de, (2017). Toyota will „bahnbrechende“ Batterie-Technologie exklusiv nutzen. [image] Available at:

Image 3: Lambert, F. (2015) Toyota unveils new tech for the Prius, will offer two choices of battery packs with higher energy density. [image] Available at:

Image 4: Toyota, (2017). Introducing the new 2017 Toyota Prius Plug-in. [image] Available at:

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