Near-future cars

How far away is mass marketing of electric vehicles?

Electric vehicles are being taken more seriously than ever before. And not just by environmentalists and electrical engineers. Some of the world’s biggest car companies are finally seeing the writing on the wall.

Is this a positive evolution? In my opinion, it certainly is. Even if the electricity is produced with coal-fired power stations without carbon capture, a plug-in hybrid car will still emit about 25 per cent less CO2 over its life cycle than a standard gasoline car [1]. Moreover, electricity generation is evolving towards an increasing share of carbon free renewables in its energy mix.

Yet in spite of this, the U.S. House Committee on Energy and Commerce is considering subsidizing the production of coal-to-liquid transport fuels. One has to wonder why, since that option results in approximately double the CO2 emissions compared to the coal-to-electricity option.

Does the current interest mean that mass production of electrical vehicles is on the horizon? Yes, but it is not likely to be tomorrow. First of all, the current hype is based more on promises and prospects than any hard facts and proven hardware. The inescapable truth is that there are still no true electrically powered standard cars available on the mass market. Secondly, what will be achieved in the market as a whole in the next few years depends largely on progress in battery technology, and more specifically, lithium-ion battery technology [2].

The Toyota Prius — good but not great

What about the Toyota Prius? I don’t think you can call the Prius an electric vehicle even with a generous definition of what qualifies as an electric car. It is a gasoline powered vehicle with an oversized battery and regenerative breaking to improve efficiency. Moreover, its environmental performance is overrated. George Monbiot even accused Toyota of greenwashing ('Greenwash Exposed – Toyota' on Celsias [3]). He points out that back in 1983, a standard Peugeot 205 managed to get 72 miles per gallon on highways. The Toyota Prius, on the other hand, does only 51 miles per gallon. George Monbiot’s conclusion is that efficiency improvements on cars in the past quarter century were merely used to improve performance, not to reduce fuel consumption.

Electric microcars for commuter traffic

The only fully electric powered vehicles available today are microcars like the Smart EV [4], the REVA-NXG [5] and the Tango [6]. These city cars are still expensive, built in small series, and not available in all countries. The two-seat Tango by Commuter Cars is an interesting concept. It has half the width of a standard car, allowing it to pass through traffic jams almost like a motor cycle. It can use either lead-acid batteries giving it a driving range of 40-80 miles, or the more expensive NiMH batteries that extend the range to 60-160 miles. The lead-acid batteries can charge to 80 per cent in just 10 minutes from a 200 amp charging station, with a full charge taking no more than 3 hours.

When will the first plug-in hybrids be released?

In the meantime we are still waiting on the first plug-in hybrids to arrive on the mass market. And we will probably still be waiting for three or more years. The first Tesla Roadsters are scheduled to hit the road in the first quarter of 2008, but this car is an exclusive and expensive sports car. GM has announced that the Chevrolet Volt and the Opel Flextrum will be available on the market around 2010.

The Chevrolet Volt [7] will have a single full charge electric-only driving range of 40 miles. A full charge will take 6.5 hours from a standard North American 120-volt, 20-Amp outlet. Unlike the Toyota Prius, it will be a series hybrid, meaning that its internal combustion engine is not directly connected to the wheels but is hooked to a generator that can resupply the batteries. This combustion motor increases the vehicle's driving range to 640 miles. The Chevrolet Volt is expected to cost $20,000 to $30,000.

Toyota and Ford are also working on an affordable plug-in hybrid vehicle, but have yet to announce a possible year of release.

It all depends on battery technology

The reason why the year of release for the plug-in vehicles appears so uncertain is that lithium-ion battery technology is not yet fully mature. Cost, cell life, and safety remain unresolved concerns.

Today, a small 12V Lithium-ion battery costs about $450/kWh or ten times the price of a traditional lead-acid battery. Moreover, the cost of the longer-life, more robust version suitable for use in electric vehicles rises to about $700/kWh, still more than double the $300 target.

The lifespan of even the most advanced types of lithium-ion batteries are only marginally acceptable for use in the automotive industry. The most recent lithium-ion battery packs are designed to last for about 10 years and 5,000 full-discharge cycles. That is quite an achievement but still not good enough.

The biggest concern in the development of lithium-ion batteries is safety. Lithium-ion batteries can catch on fire and even explode. John Voelcker in the IEEE Spectrum article 'Lithium Batteries Take to the Road' [2]: 'These catastrophes happen when a cell shorts out, gets hot, and starts an exothermic oxidizing reaction that kicks the temperature to hundreds of degrees Celsius in a fraction of a second. The heat then shorts out adjacent cells to produce a runaway thermal reaction that can be spectacular (…). And, unlike a gasoline fire, the conflagration can’t be smothered, because it gets oxygen from the cell’s intrinsic chemistry.'

There are several ways to avoid such catastrophic failures. The Tesla designers chose to link a large number of small battery cells in networks, to ensure that a problem in one cell cannot propagate into others. But this is an expensive option. A123 Systems [8] and some other start-ups are focusing on adapting the fundamental reactions in the cell itself to improve safety.

Going too fast for their own good?

The chief danger in the current electric vehicles hype is that pushed by climate change concerns and high fuel prices, car companies will be forced to go faster than safe progress allows. Controlling battery technology under laboratory conditions is one thing. Mass production and use in the car industry is quite another. Ideally, the new battery designs should be rigorously tested for at least half their lifespan before going into mass production and use. But that seems to be a luxury automotive industry battery developers can’t afford.

The risk of going too fast is that battery technology will be installed prematurely in mass market cars. One battery explosion causing fatalities is all it will take to generate enough bad publicity to set the entire electric vehicle industry back a decade or more.

These are indeed exciting and challenging times for battery and electric car developers. I’m very curious to see where the technology and market will be in three or four years.

References

[1] CEIC Working Paper 'For energy security and greenhouse gas reductions, plug-in hybrids a more sensible pathway than coal to liquids gasoline', by Paulina Jaramillo and Constantine Samaras

[2] Article 'Lithium Batteries Take to the Road' by John Voelcker on IEEE Spectrum

[3] Article 'Greenwash Exposed — Toyota' by George Monbiot on Celsias

[4] Article 'Hybrid Technologies to Produce Electric Smart Car', by Michael Graham Richard in Treehugger

[5] REVA Web site

[6] Commuter Cars Web site

[7] GM Chevrolet Web site for the Chevrolet Volt

[8] A123 Systems Web site