REGISTER | LOGIN
Breaking News
News & Analysis

Supercapbatteries, Thermoelectrics to Power Future Cars

Traditional auto power sources becoming obsolete
1/30/2015 00:01 AM EST
29 comments
NO RATINGS
1 saves
More Related Links
View Comments: Newest First | Oldest First | Threaded View
Page 1 / 3   >   >>
R_Colin_Johnson
User Rank
Author
Re: Another way - Flywheel and nonmaterial
R_Colin_Johnson   2/2/2015 1:53:00 PM
NO RATINGS
IJD: Thanks for sharing your deep knowledge of flywheels and how they are only economical for busses that start-stop alot. I can see the wisdom of your argument, and I guess others can too, because others too predict that busses will be first, they just never told me why before! Thanks for clearing that up.

IJD
User Rank
Author
Re: Another way - Flywheel and nonmaterial
IJD   2/2/2015 6:50:49 AM
NO RATINGS
With flywheels inside the wheels you might have a bit of a problem turning -- have you ever played with a gyroscope?


To avoid gyroscopic effect in cars they need to be mounted with their axis vertical -- and even then may need to be gimbal-mounted to avoid problems if the car tilts left/right or goes up/down a hill. Add this to the cost of vacuum-sealing, magnetic bearings, power transfer and the economics make little sense.

And the energy density of flywheels isn't as high as lithium batteries by the time you've made them out of expensive materials and built a strong (heavy!) enough case to keep all the bits in if they break.

The only real use -- and even then it's marginal because of the cost -- is in vehicles which do a *lot* of rapid start/stop driving like buses, because unlike batteries the cycle lifetime is pretty much infinite and they store a lot more energy than supercapacitors and can get it in and out quickly.

R_Colin_Johnson
User Rank
Author
Re: Another way - Flywheel and nonmaterial
R_Colin_Johnson   2/1/2015 2:25:51 PM
NO RATINGS
Les_Slater 2/1/2015 11:28:16 AM: The mechanical engineers of today are already designing new flywheel designs, with miniscule friction and less spin-up drag. They may someday be able to put them in the wheels themselves to drastically reduce operating cost of any vehicle switching to "green wheels"!

R_Colin_Johnson
User Rank
Author
Re: Another way - Flywheel and nonmaterial
R_Colin_Johnson   2/1/2015 2:20:52 PM
NO RATINGS
hm_:After thinking about it, I agree with both your points. First of all flywheels are definitely the greenest solution, and secondly they may be old-school to old-timers, but all the marketing department has to do is rename them something comtemporary like "green energy spinner" or something hip :)

Les_Slater
User Rank
Author
Re: Another way - Flywheel and nonmaterial
Les_Slater   2/1/2015 11:28:16 AM
NO RATINGS
_hm, as far as I can tell the flywheel is being considered as a higher energy density alternative to the battery, current technology is nowhere near approaching chemically stored energy such as in hydrocarbon fuels and their relatively close alternatives.

Not sure how nanotechnology might effect energy density. We can reduce required mass by increasing rotational velocity but still leaves the problem of coupling the energy to and from such a flywheel.

Lithium batteries are being used for all electric vehicles presently. Some examples of such have quite spectacular power at their disposal and some even quite usable range, but not both at the same time. It is possible that flywheel could provide a decent measure of both.

_hm
User Rank
Author
Re: Another way - Flywheel and nonmaterial
_hm   2/1/2015 9:30:01 AM
NO RATINGS
@R_Colin_Jhonson: Yes, I know it is so called old school. But in hindsight, there is nonesuch as old school!. Also, flywheel may be greenest of all. What I was suggesting is  that with new nano materials and other new technologies, this simple concept can again be revisited.

Les_Slater
User Rank
Author
Re: Thermal dynamics of internal combustion
Les_Slater   2/1/2015 5:35:53 AM
NO RATINGS
The crankshaft has many limitations and problems, the chief among them is the fixed geometric relationship between angular position of the crank and the linear position of the piston within the cylinder. This translates, within engine displacement and weight constraints, to a very large mismatch between combustion energy and shaft output energy, whether that be used directly for propulsion or storage of any sort.

R_Colin_Johnson
User Rank
Author
Re: Another way - Flywheel and nonmaterial
R_Colin_Johnson   2/1/2015 12:14:52 AM
NO RATINGS
_hm: Yes, there is a lot of talk about flywheels--that's an old school solution. My first job (while still in high school) was a paper bag factory for Purina Chow--did you know there is such a thing as Rat Chow? Anyway, I digress, every machine in that old factory had a flywheel on it that turned sometimes as much as an hour after it was shut down. A lot of energy can be stored in flywheels for stamp dies and such. Its a good solution for cars, but so old-school that people don't want to use them. Thanks for the blast from the past, even though its a good solution even today.

_hm
User Rank
Author
Another way - Flywheel and nonmaterial
_hm   1/31/2015 5:35:06 PM
NO RATINGS
I like to see some progress in electro-mechanical flywheel with nano-material to enhance the car range to 80mpg range.

R_Colin_Johnson
User Rank
Author
Re: Thermal dynamics of internal combustion
R_Colin_Johnson   1/31/2015 3:15:00 PM
NO RATINGS
Les_Slater: Yes you are right about the total lifetime energy savings. Also these thermoelectric materials are getting cheaper and cheaper and at the same time more and more efficient. It may soon be a no-brainer to recapture heat energy and turn it into electricity. With approximately one billion cars on the street to day and the two billion mark coming before the end of the decade, it may even contribute to cooling the planet or at least crowded metropolitan areas like New York City.

Page 1 / 3   >   >>
Like Us on Facebook
EE Times on Twitter
EE Times Twitter Feed