Friday, February 04, 2011

Ultra Capacitors and Electric Cars


Maxwell Technology Inc.
New Ultra-Capacitor

How about an electric drill that can be fully charged in just 60 seconds instead of 60 minutes!! So who is promising that sort of hyper upgrade?

A company called Maxwell Technology, who have been recently in the news for their “Ultra Capacitors”, have announced yet another new breed of these super-duper capacitors.

Batteries v/s Capacitors

Batteries are chemical factories. When you put electricity into a battery it causes heat, gas, and major chemical changes in the elements of the battery. This chemical action has to be slowed down, because if it happened too quickly, it would essentially be an explosion. No doubt, you have read about laptop computer batteries going on fire? This can happen when the battery is either charged too quickly, or is discharged too quickly.

What all this means, is that batteries, because of the chemical, heat, and gas reactions;
(1)    Take time to charge up.
(2)    Have to be discharged at a slow controlled rate,
(3)    Wear out very quickly due to chemical reactions eating away at the metal electrodes.

In comparison, a capacitor has NO chemical reaction. Therefore, a capacitor does not generate gas, heat, or chemical erosion. Therefore, a capacitor will last a long - long time compared to any battery.

Additionally, a capacitor can be charged and discharge VERY quickly. This ability to rapidly take in and give out large amounts of electricity is very useful in the real world. The electric drill mentioned above for instance, could be plugged into a suitable high-speed charged and charged in one or two minutes. The torque power of the drill would also be much greater due to the high current ability of the capacitors.

Electric Cars and Ultra Capacitors

Now where untracapacitors would be really- really - really great would be in electric cars. However, up till now unltracapacitors have been WAY too bulky to be of practical use. In other words, they would need ALL the space in a car to give sufficient power for anything but a very shot journey.

But now Maxwell technology have announced the following:

"In a simplified comparison of how powerful and quick Maxwell's ultracaps are, a lead acid battery takes 10 hours to fully charge. A lithium ion battery will charge in about an hour."

"A Maxwell ultracapacitor will charge in half a second and contain 10 times or more energy per ounce than any battery option."

Let me get this straight, take a bog basic 12 volt car battery, the size is about 30cm x 23cm x 18cm and weighs in around 15Kgs. This battery gives roughly 40 Amp Hours of electrical capacity. Basically calculated, but in real life it doesn’t quite work the same, the battery is 12 Volts multiplied by 40 Amps gives you 480 Watts, and it can sustain that wattage for 1 hour.

Now if I read the Maxwell statement correctly, "10 times or more energy per ounce than any battery", they say that for the same 15Kgs weight of the above battery their ultra capacitors should give you a minimum of 4.8Kw for 1 hour, but more like some 7+Kw,  for 1 hour. Taking into account that a lead acid battery is about half as efficient as a lithium ion battery - and that their capacitor holds "10 times or more energy per ounce than any battery". Now if that is a completely true and honest statement - it is amazing!  How true it turns out to be in the real world - remains to be seen.

Electric Cars and Maxwell Ultra Capacitors

If the Maxwell statement can be fully and literally taken as completely true, then electric cars are in for one hell of a boost. Because for one tenth of the weight of the current lithium ion batteries, they can have the same energy. Additionally, these cars could be fully charged up in about the same time it takes to fill the gas tank.

Will we see the statement realised?

Will we ever see the Maxwell Capacitor statement fully realised??? Good question - even though I say so myself!

To date, all claims made for super batteries etc. have neither been seen or heard of - other than the copious “Hot Air” that has been pumped out by the company publicity spin doctors in looking for investors. Hence my own invention: "The Hot-Air Battery"

Is Maxwell technology any different?


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