For many drivers of conventional vehicles, the thought of limited range and long charging times makes them shy away from electric vehicles.
Of course, if you really take the time to consider how many miles are driven each day, then one can easily see how an electric vehicle can fit into the average driver’s life. According to the Union of Concerned Scientists, for example, some 45 million American households could make the switch to electric vehicles without making any changes in their current driving habits. That’s 42% of the United States, yet just one percent of Americans own electric vehicles.
Still, many people can’t make the mental leap necessary to overcome range anxiety, but what if there was an electric vehicle that nearly eliminated it? The Tesla Model S 85 kWh has the best range of any electric vehicle, but still is less than most conventional vehicles. Last year, Tesla Motors applied for a patent that would increase its effective range far beyond even conventional vehicles. The range-extender, however, isn’t like the gasoline-powered generator, the range extender in a Chevy Volt or BMW i3, but a second battery. In addition to the the lithium-ion battery pack, the patent includes a second, metal-air battery pack.
There’s one caveat, however. The lithium-ion battery pack can be cycled a few hundred times before it’s performance begins to degrade, which means it has a good balance of range and lifespan. Metal-air batteries, however, have a very limited lifespan, that is, they can discharge one time, and one time only. Tesla hasn’t put one into production yet, but there is a demonstrator vehicle being tested in Montreal, Canada. Phinergy and Alcoa are testing an electric vehicle with both lithium-ion and aluminum-air battery packs.
The lithium-ion battery in this particular electric vehicle testbed is still the primary battery, with the aluminum-air battery functioning as a range extender in case of a long trip. Owners would need to keep the aluminum-air battery topped off with tap water to enable chemical reactions inside. Alcoa estimates that the aluminum-air battery pack would need to be changes once a year, or less. The only question is, “How much does this convenience cost?”
Image © Alcoa