Tuesday, 17 September 2013

Update on electric cars

On the argument that electric cars charged off the grid are just burning fossil fuels in a different way.

This is mainly aimed at the USA where the coal is just scraped of the surface as opposed to being mined. The Germans get their coal this way but started the push for renewable 2 decades before the USA knew it existed.

The conclusion: Even in the few states with the very dirtiest grids, driving a mile on grid electricity is barely worse than the most fuel-efficient non-hybrid car (roughly 34 mpg).

And in states with the cleanest grids, there's no combustion-engine vehicle that can match an electric car for low carbon emissions. Most recent research has come up with broadly similar conclusions.
To use the nation's reliance on dirty coal as an argument against electric cars is looking at the argument form the wrong side. Don’t blame the car, blame the grid. The only thing to be questioned is a dogged continued reliance on coal.

The next stage is to improve cars - the distance electric vehicle can travel in a single charge and the charging time.

Anything beyond 125 mile range was becoming challenging and the charging time anything less than 1.5 hours was also tough to design.

Things are getting better with the new Tesla – 300 miles on a single charge and a further r125 mile on a 20 minute recharge

The technology behind this is advanced lithium based and other fast charging high-density batteries coupled with super capacitors. Super capacitors can be charged faster which can charge the lithium batteries while the car is moving.

The final hurdle is the cost of the electric car

In smaller electric cars, installing solar PV arrays on rooftop is not bad idea.  We are quite keen to see how the World Solar Challenge going pans out, to be held in Australia on 6th of October 2013. The 7 day solar powered car race covers 3021 km cutting through the Australia from north to south. Some of the earlier winners of this race have reached average speeds of 100 kilometres per hour purely on solar electric power. For electric car designers watching this event closely may give some ideas on efficiency and design.

Panasonic is sourcing lithium ion batteries and solar PV cells to Tokai University team, which is participating in World Solar Challenge 2013. Panasonic says its HIT solar cells suffer less degradation of power output at high temperatures, delivering the industry's highest-level energy output per unit of area. The rechargeable batteries Panasonic is providing are the cylindrical 18650 type (18 mm in diameter x 65 mm in height) high-capacity lithium-ion battery cells which use the company's proprietary nickel-based positive electrode. The high-capacity and lightweight battery cells store excess power generated by the HIT solar cells so that the car is able to continue running.

The different vehicle technologies will dominate in different transport segments, and all have advantages and disadvantages. We must therefore assess both the vehicle and its environmental soundness in a cradle-to-grave perspective

Battery Tech
We are waiting for the day when batteries quadruple in their capacity to store energy.

There are some fundamentals about lithium that will never change. Though some say there's plenty of lithium on the planet with which to do what we want, it's not exactly easy to extract from resources and many of those resources are too small be money makers, thus may never be developed.

Once you've got your lithium it's an absolute pain to work with. As soon as your metal is open to the air it begins to oxidize. Immediately. Rapidly. So your battery electrochemistry or your manufacturing process has to deal with that instant oxidation problem. Extremely difficult to work with in a manufacturing sense translates into high productions costs. Battery cell makers combat productions costs with cheap labour. That's not a great solution.

Now there's another possibility just starting up in the development stage
Scientists from General Electric and Berkeley Lab are working on a flow battery prototype
And they're not alone. The Illinois Institute of Technology (ITT) and Argonne National Lab will share a $3.4 million award from U.S. Department of Energy's Advanced Research Projects Agency to develop a prototype of their "nanoelectrofuel" flow battery.

If you've never heard of a flow battery it's a type of fuel cell where dissolved electroactive elements in liquid electrolytes flow on either side of a membrane within a cell. A charged ion exchange takes place as the electrolytes pass each other on either side of that membrane to generate electric current. The chemical makeup of the electrolytes determines the voltage in each cell. Building a stack of cells, and adding each cell's voltage together, increases the voltage available for work. The cumulative area of the reactive portions of the cells, where the membrane is, determines the amount of electric current available. And the runtime of the flow battery is determined by volume of stored electrolytes. Electrolyte is held in tanks and pumped through the cells. In an electric car runtime means range and the bigger the tanks the farther the car will go, just like fuelling with petrol.

There's evidence that flow batteries could be an alternative to lithium.

We all know that the technology is expensive, and that many operators are waiting until more experience is available. But this must be broken. As long as nobody dares to get involved, no new and more efficient technologies can be developed, either

Watch this space

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