Battery technology is the key to EV Growth

In order for Electric Vehicles to enter the mainstream and compete equally with petroleum powered vehicles, battery technology must improve.

I consider the Nissan Leaf to be the one of the most important electric vehicles on the market today. Unlike the Prius or even the Volt, the Leaf is not a hybrid electric vehicle but a completely electric one. It is powered by an electric motor and energy is stored in the car's battery packs. The Leaf will not need to be "filled up" with petroleum, it needs to be plugged in to ensure that its rechargeable batteries have enough juice to keep the Leaf going.

The problem is that, while the cost of charging a car with electricity is very low compared to the cost of filling up a car with petroleum, the range of the Leaf is disconcertingly small. "Range anxiety" prevents many Leaf owners today from driving their vehicles beyond the normal commute. As a result it is more likely to be owned by people who already own petroleum powered cars that have greater range that they can use when needed. Nissan says that the Leaf's range is 160km but that is a very optimistic figure which does not take into account normal driving patterns: an "eco" mode ensures that acceleration is lower than it could be. In "normal" mode, and taking into account the need for air conditioning, heating, and music, the range of the Leaf is more likely to average out at 117km.

(Such normal driving patterns also lower the range of petroleum powered vehicles as well - it's just that we don't notice it too much because the car's range is still reasonably high).

After consulting the specs of my own comparable vehicle (A Mitsubishi Lancer) I have determined that modern cars need a range of around 600km. This would mean that, in order to properly compete, the Nissan Leaf's batteries would need to store 5.128205128 times more energy than it does currently.

And this is where the engineering challenges can be quantified.

The Automotive Energy Supply Corporation (AESC) is the company that builds the Battery Packs for the Nissan Leaf. Have a look at the specs on their product here.

From these specs we notice a number of things:
  1. The Nissan Leaf does not have one battery pack, but 48 individual packs located under the car's floor.
  2. According to the Leaf's specs, the total amount of energy stored in these 48 packs is 24 kilowatt hours (Kw/h).
  3. Therefore, each battery pack contains, on average, 500 W/h.
  4. Each individual battery pack weighs 3.8kg.
  5. Therefore, the energy density of each battery pack is 131.57 W/h per kilogram.
So in order for the Leaf to have a 600km range, each battery pack should store 2.56 Kw/h of energy, which means that the energy density of these battery packs must increase to approximately 675 Wh/kg (while assuming no increase in volume).

Of course battery technology is progressing in leaps and bounds - anyone who owns a mobile phone or laptop knows that storage capacity has improved considerably over the last five years. Nevertheless while the technology is moving forward, we need to remember that there is usually a lag between the technology being discovered and its ability to be mass produced at a reasonably low price.

I am quite confident that these technological and industrial goals can be met some time in the next 10-12 years.

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