XI. In pairs retell the article using a figure and key words as a support ( or do it in writing).

Key words:

Verbs:oxidize, reduce, emit (electrons), (electrons) enter, dissolve, charge, discharge, bind ( bound), coat, extend.

Nouns:electrolyte, anode, cathode, lithium-ion, silicon-based material, separator, (surface) treatment, binder, lifetime, energy density, vehicle, voltage, energy density.

* More information about the physics and chemistry of electric batteries are available at http://www.youtube.com/watch?v=OtfKux9BUnE

Video ‘Electric Car Batteries of the Future’

Panel discussion ideas.

These extracts are taken from blogs and posts written by journalists, not by scientists, so the style is far from being academic. We suggest reading them for better understanding the challenges that the topic ‘Electric cars’ present.

Jason Jungreis http://www.intelligentutility.com/article/13/07/future-electric-vehicle :. also available at http://www.energycentral.com/enduse/electricvehicles/articles/2680/The-Future-of-Electric-Vehicles

http://www.caranddriver.com/features/whats-new-fast-forward-2020-the-myth-of-the-ev-future Against electric cars : What's New: Fast Forward 2020: The Myth of the EV Future

II. Work in teams of three. Each team member reads one extract and writes 5 comprehension questions for the other two students. Then work out answers together.

Student 1.

In the near future (in approximately 5 years), we may see the following advancements:

Batteries: Lithium batteries with silicon-based cathodes, which can absorb many lithium ions and therefore would provide the battery with dramatically more energy storage. Today, relatively common lithium chemistry can contain around 133 watt hours/kilogram (wh/kg). This is about enough energy to drive an EV half a mile. With silicon cathodes, the energy density would likely be around 400 wh/kg - three times better than today's common batteries. With a 400wh/kg battery, a 150 mile range battery pack will only weigh about 220 pounds.

In order to build silicon-based cathodes, it is likely that nano-sized silicon will be contained in porous ceramics or other materials that allow for sufficient surface area and yet keep the silicon from physically crushing itself as it expands when absorbing the lithium ions.. This means that even a small battery pack, such as that found in EVs, could provide adequate power to accelerate quickly, and allow a maximum amount of regenerated (braking) electricity to be put back into the battery.

Construction: More of the vehicle's components will be made from aluminum and high-strength steel construction. This will serve to lighten the vehicle, and low weight is the key to efficiency and performance. Vehicles basically use energy to accelerate, to push through the air, and to overcome friction.
Obviously, though, you don't want to make a car out of balsa wood, as it would not protect its passengers . Therefore, building a vehicle from strong but light components is critical. Here, there are numerous interesting developments in improved metal alloys, such as better aluminum and better steel, and improved construction techniques such as welding steel and aluminum together and employing powerful bonding agents, that will allow lighter and more rigid chassis, suspension elements, and body parts.

Student 2.

Looking ahead to the mid-future (in approximately 10 years), we may see the following advancements:

Batteries: Lithium sulfur, lithium salt-water, or possibly lithium air batteries. These batteries promise over 1000 wh/kg, which would enable 600 mile trips with a battery weighing around 350 pounds.

Charging: With improved batteries that accept electricity quickly, charging will take less time - if the charging station is up to the task of pumping all that electricity in quickly. It may be hoped that there will be a fast-charging standard of at least 100KW. Using such a charging station, for every minute that the EV is plugged in it can drive about 6 miles - this means that in an hour, the car would receive enough electricity to drive 360 miles.

Looking ahead to the longer-future (in approximately 15-20 years), we may see the following advancements:
1. Batteries: While it is still quite early to know what will be its ultimate uses, the wonder material of the 21st century appears to be graphene. It is a single sheet of carbon atoms, and it is being investigated for several electricity-based applications, as the basis for ultra-strong materials construction, even as a scaffold for growing organ tissue, and more. For purposes of storing electricity, graphene seems to be able to quickly absorb tremendous amounts of electrons, hold them without significant loss, and then release them just as quickly. In this way, graphene seems most like a superdupercapacitor. Capacitors generally differ from batteries in their ability to efficiently hold an electrical charge and then quickly release it: they have high power density, however they generally cannot hold as much energy as a battery and thus have lower energy density. But, at some point, the line between energy density and power density blurs, and so whether graphene might ultimately be seen as a battery or as a capacitor is irrelevant.

Student 3.

Date: 2016-03-03; view: 1396