It’s been too long since I’ve done a “how cool is that?” expression of awe and wonder at a piece of ingenious creativity. You may recall that early automobiles were battery-powered — the origins of the electric car are deep and over a century old. One battery technology, courtesy of (you guessed it) Thomas Edison, was nickel-iron; Edison was a proponent of electric vehicles.
Stanford researchers have been working on improving the performance of Edison’s nickel-iron battery, contributing to the portfolio of battery technologies that can improve electricity storage, which is the Holy Grail of electricity technology. As described by Stanford News,
“The Edison battery is very durable, but it has a number of drawbacks,” said Hongjie Dai, professor of chemistry. “A typical battery can take hours to charge, and the rate of discharge is also very slow.”
Now, Dai and his colleagues have dramatically improved the performance of this century-old technology. The Stanford team has created an ultrafast nickel-iron battery that can be fully charged in about 2 minutes and discharged in less than 30 seconds. …
Carbon has long been used to enhance electrical conductivity in electrodes. To improve the Edison battery’s performance, the Stanford team used graphene – nanosized sheets of carbon that are only 1-atom thick – and multi-walled carbon nanotubes, each consisting of about 10 concentric graphene sheets rolled together. …
“Our battery probably won’t be able to power an electric car by itself because the energy density is not ideal,” Wang said. “But it could assist lithium-ion batteries by giving them a real power boost for faster acceleration and regenerative braking.”
This approach to energy storage, using strongly-coupled nanomaterials, has a lot of promise for battery researchers working to improve efficiency, density, and charge decay over time.
All claims of fast charging batteries are meaningless for uses other than the sorts of small electronics that use milliamps of electricity. For macroscopic uses such as transportation propulsion what is relevant in limiting charge times is circuit and grid capacities.
The first thing to remember about charging is the fundamental rule of electric current:
watts = volts * amps
A regular US household circuit is fused at a maximum of 120 volts and 15 amps. Its maximum power level is 1800 watts. It can deliver a maximum of 1.8 KW. The BEV people call this level 1 charging.
Lines used for major household appliances such as ovens and dryers are fused at 240 Volts and 30 Amps. This is Level 2 charging. A level 2 charger in your garage will set you back a couple of thousand dollars. It can deliver a maximum of 7.2 KW.
If your BEV holds a full charge of 24 KWh, it will not take less than 13 hrs 20 min to charge on a level 1 or less than 3hrs 20 min on a level 2.
One way of looking at this is to think of charging as a speed figure for the vehicle. I have seen claims of electricity use by BEVs of between 3 and 5 miles per KWh of charge. A level one charge fills the car up at between 5.4 mph and 9 mph. It’s faster than walking, but not a whole lot.
A level 2 charge can be between 21 and 36 mph. Car like speeds to be sure, but satisfactory only for in town driving.
It takes about 15 min to put 15 gal of regular in to my Honda which will take me 300 miles easily. That would be 1200 mph — supersonic. This is why BEVs are inferior and always will be.
BTW: The do not pollute less:
“Unclean at Any Speed: Electric cars don’t solve the automobile’s environmental problems”
By Ozzie Zehner, Posted 30 Jun 2013.
http://spectrum.ieee.org/energy/renewables/unclean-at-any-speed
Spectrum is a publication of the Institute of Electrical and Electronics Engineers, they are not beholden to the oil companies.