Turning over the Nissan LEAF (to look inside)

It’s risky to closely examine any product which isn’t going to be available until at least 1 year into the future. The manufacturer may change some things before finalizing the product. Still Nissan has published enough information about the LEAF to give us room to examine the details and do some informed speculation. For an overview of this interesting new electric car take a look at the previous articles in this series: part 1: Nissan announces the LEAF, an affordable zero-emissions electric car, part 2: Range anxiety and the new Nissan LEAF EV, part 3: Technical specifications for the Nissan LEAF

Let’s start with the electric motor. Rather than “horsepower” they give ratings in kilowatts (80kW) and torque (280Nm). Horsepower calculations are arrived at differently for electric motors and internal combustion engines. There is a rule of thumb that 750 watts is equal to 1HP, meaning the LEAF’s electric motor is equivalent to 106 HP. However the real measure of importance is supposed to be the torque (force) the motor puts out. Unfortunately torque is not directly convertible to horsepower without knowing some other factoids about the car design.

Another factoid is that in an electric motor the torque is fully available the moment you touch the throttle, unlike a gas engine where the torque builds up over time. While electric motor torque can be fully available instantly, vehicle designers can designed the throttle response curve. Since Nissan intends this car to be a normal sedan they may have designed in a moderate acceleration curve rather than a real sporty one.

Now let’s turn to the battery pack. It’s a “laminated” battery pack using lithium ion manganese chemistry. The lithium ion manganese is one of the safer forms of lithium batteries, and has a number of benefits including a higher charge rate.

To understand what they mean by “laminated” we have to turn to a recent Motor Trend blog entry Driving the Future: Nissan’s All New Electric Vehicle. They show pictures of the battery cells, which are rectangular in shape. Battery cells come in either cylindrical or rectangular packages. Nissan representatives say these rectangular cells are more efficient space-wise packing battery capacity into the available space, and are easier to cool.

The rated capacity is 24 kilowatt-hours and that’s a lot of electricity. Kilowatt-hours are the electrical equivalent to gallons of gasoline, hence the more kilowatt-hours in the battery pack the longer the range. Note that Nissan claims a 100 mile range for the LEAF, and the Tesla Roadster (with a 53 kilowatt-hour battery pack) claims a 230 mile range. Of course the actual range a specific driver will get depends on their driving habits.

The rated power output is 90 kilowatts, or a bit more than the 80 kilowatt rating of the motor. By comparison a typical clothes washer requires 1 kilowatt (or less) to run, and the typical 100 watt lightbulb requires, well, 100 watts to run. The LEAF at maximum power output is the same as running 800 light-bulbs or 80 washing machines. That may seem like a lot of power (and it is) however if one were to convert the power in a gasoline burning car to electricity the power levels would be similar.

For more info:

How do you convert engine torque to horsepower?What Is Torque, What is HP?

Torque Versus Horsepower – More Than You Really Wanted to Know

Unit converter

Torque (wikipedia)

Horsepower (wikipedia)

Lithium-ion Battery (Wikipedia)

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About David Herron

David Herron is a writer and software engineer living in Silicon Valley. He primarily writes about electric vehicles, clean energy systems, climate change, peak oil and related issues. When not writing he indulges in software projects and is sometimes employed as a software engineer. David has written for sites like PlugInCars and TorqueNews, and worked for companies like Sun Microsystems and Yahoo.