Plastic Batteries Coming Soon?

Roland Piquepaille writes "Engineers at Brown University have built a prototype of a hybrid plastic battery that uses a conductive polymer. The system, which marries the power of a capacitor with the storage capacity of a battery, can store and deliver power efficiently. For example, during performance testing, 'it delivered more than 100 times the power of a standard alkaline battery.' Still, it's unlikely that such a device can appear on the market before several years."

Comments

Ouch

[CrazyJim1]

'it delivered more than 100 times the power of a standard alkaline battery.', slurred the engineer with the scortched tounge.

Five to ten years...

[MythoBeast]

Why is it that we keep hearing about this kind of advancement "to be available in five to ten years", and yet the storage capacity of batteries has been stagnated for at least that long?

Re:Five to ten years...

[jellomizer]

Batteries tend to improve linearly while electronics tend to improve exponentially. So this really makes batteries seem like they are stagnant. If batteris went at the same speed as electronics. A nuclear power-plant will be in a AAA Battery.

Re:Five to ten years...

[luder]

Well, unless I'm missing something here, if it delivers 100 times more power than an ordinary battery then it also increases it's life:

P = V*I
100P = V*I
I = 100 (P/V)

For example, most powerfull easy to find rechargeable AA batteries can deliver 2.5A, or 3W, at 1.2V.

P1 = 1.2 * 2.5
P1 = 3W

This battery can power a 3W, or 2.5A, device for an hour.

With an increase of 100 times more power we have:

P2 = 100 * P1
P2 = 100 * 3
P2 = 300W

The new battery could power the 3W device for 100 hours, instead of the 1 hour that the current battery can do, or a 300W device for a single hour.

Re:Five to ten years...

[flooey]

Well, unless I'm missing something here, if it delivers 100 times more power than an ordinary battery then it also increases it's life:

You're confusing power with energy (which is easy to do, considering your "power bill" is actually a bill for energy used, not power). What it's saying is that its peak power delivery is 100 times that of a normal battery, so at a given voltage, it can deliver 100 times the current of a standard battery. It could well be able to store the same amount of energy, though, which means that if you're running it at its improved full power it dies in 1/100 the time of a normal battery.

Re:Five to ten years...

[hernick]

Yes, you are missing something very important.

You've introduced three units in your calculations:
  * Power (P, in Watts W)
  * Voltage (V, in Volts V)
  * Current (I, in Amperes A)

However, these units only measure energy at a single point in time. But we're dealing with finite energy sources. We need to introduce another unit:
  * Time (T, in Hours h, or in Seconds s)

Let's take a new look at your formula, adding a variable for time:
  P * h = V * I * h

Now, let us consider a the same NiMH AA battery that you looked at earlier. To know how powerful that battery is, we need two know two things:
  * Its cell voltage: 1.2V
  * Its capacity rating: 2.5Ah (normally quoted in mAh / you'd see 2500mAh in the specs)
  * It's maximum power drain: 2.5A

These two numbers tell us that roughly, this AA battery can deliver its quoted voltage of 1.2V for one hour if the current drain is 2.5A.

P1 = 1.2V * 2.5A * 1h
P1 = 3W * 1h = 1.2V * 2.5Ah
P1 = 3Wh = 1.2V * 2.5Ah

This battery can power a device with a power draw of 3W (equivalent to a current draw of 2.5A at a voltage of 1.2V) for one hour. It has a capacity of 3Wh (equivalent to a capacity rating of 2.5Ah at a cell voltage of 1.2V).

Let's assume that these are the specs for our new battery:
  * Its cell voltage: 1.2V
  * Its capacity rating: 2.5Ah
  * It's maximum power drain: 250A

Now, this is where you get it wrong. What we're doing is increasing the power drain by 100, not increasing the capacity by 100.

P1 = 3W * 1h = 1.2V * 2.5A * 1h

P2 = 3W / 100 * 100 * 1h = 1.2V * 2.5A * 100 * 1h / 100
P2 = 3W * 1h = 1.2V * 250A * 0.01h
P2 = 3Wh = 1.2V * 250A * 36s
P2 = 3Wh = 1.2V * 2.5Ah

So, the new battery could power the 3W device for 1 hour, or a 300W device for 36 seconds.

Now, in reality, this new battery/capacitor hybrid is likely to have a far lower capacity rating (quoted in mAh on the box) than your typical NiMH AA cell. Also, the typical AA cell has a higher maximum power drain, which can be increased further by cooling the battery as you discharge it.

Also, in the real world, things don't work out quite as nicely as in these equations - there are power losses that vary based on a lot of factors. How fast is the battery discharged? How hot is it - and the more quickly you discharge it, the hotter it becomes, the less efficient it becomes. Is it a continuous discharge load or are we looking at spikes that give it time to cool down?

Anyway. This battery isn't quite the revolution your flawed calculations would indicate.

The engines canna take it no more!

[davidwr]

Kirk: More power Scotty!
Scotty: The engines, they canna take it no more, they'll blow for sure
ENERGIZER BUNNY INTERRUPTS: *clang* *clang* *clang*
Announcer: Compared to regular dilithium crystals engines powered by new Energizer Polymer crystals last twice as long.
ENERGIZER BUNNY: *clang* *clang* *clang*
[fade to black, Enterprise exploding in the background]

Average time-to-market?

[linkedlinked]

How long, on average, does it take for a new technology (especially battery related) to reach the market, after an announcement like this?

I ask, because I've been reading slashdot for over 4 years, and it seems like there's a healthy number of "revolutionary power supply" breakthroughs, or "batteries that will change your life (for cheap!)," and today, my new laptop still dies after an hour and a half.

I don't mean to be a cynic, but it really feels like these ideas never make it out of the lab.

Re:Average time-to-market?

[MtViewGuy]

I can understand your skepticism, but this breakthrough--along with MIT's research into using carbon nanotubes to build superior supercapacitor storage devices--could drastically change the world as we know it for two reasons:

1. It opens the door for a truly practical electric car, one that uses a far smaller battery pack (which means more passenger/cargo space and less battery "dead weight" to lug around) with very long range and recharge times about the same as one refilling the fuel tank in a passenger car.

2. It makes it possible for large-scale storage of electric power, meaning power generated by wind turbines and/or solar cell farms can be stored for future use when the wind speed is low and during the night.

Re:Average time-to-market?

[Orange Crush]

So then it would be just like a gas tank, right?

Gas tanks don't explode in the real world like they do on movies & tv. Gasoline needs to be in a fine mist to become explosive--a puddle of gasoline will only burn as quickly as it can breathe in oxygen. A capacitor on the other hand can release all of its stored energy instantly. A big enough cap to power a car would go off like a bomb.

Obviously they'll have safety circuitry to prevent that from happening in the event of a short . . . but I still haven't heard how they intend to make them safe in a car crash, when the capacitor itself might get ruptured or crushed.

summary is pretty bad, this is not a revolution

[arete]

The summary is pretty bad. If I'm reading the article right:

This is neat, but not a revolution, it's exactly the hybrid of a battery and a capacitor - it has some advantages of both.

This device has similar or less storage capacity than a battery, but can deliver its power much faster.
It has similar or less power delivery abilities than a capacitor, but twice the storage capacity.

In MANY devices, the real problem is that the batteries drain. This doesn't help that in the least bit. This will not make your electric car go farther. This only helps the situation with ultra-high-drain requirements, where a normal battery just wouldn't work.

CAPACITY, not power, is important...

[dpbsmith]

...for most of the things I care about. And this device only had double thecapacity of an an alkaline battery. Capacity is mAh. Power is watts.

An alkaline battery might have a capacity of (say) 2000 mAh, meaning that it could power a three-watt bulb for about an hour. This device, if it lives up to the claims, could do so for about two hours.

An alkaline battery couldn't power a 100-watt bulb at all, because it can't deliver more than a few amps. This device apparently _could_ power a 100-watt bulb... but only for about four minutes.

The ability to deliver power, that is to deliver energy in a short, intense burst, might be very useful for some applications. But it wouldn't let you recharge your laptop once a week or anything like that.

(There's another question I have. A battery hold an almost steady voltage for a long time, then declines fairly rapidly. Almost a square wave. This is one reason why it's hard to measure discharge state. Presumably these ultracapacitors have a smooth, exponential voltage decline, like radioactive decay. That probably means that you need tricky circuitry to exploit them... and there is probably always a significant amount of power in the device that you can't use, because the voltage has dropped too low).

Roland the Plogger again

[Animats]

Ah, Roland the Plogger again.

First, this isn't about a battery with a 100x higher energy density. That would be a major breakthrough. It's about one with a high peak power, for surge applications. That's a specialty item.

It's also been done. Flat batteries with high peak-power outputs were invented over 25 years ago at Polaroid, for the PolaPulse battery. One of those was in every Polaroid film pack for years. It could put out 15 amps for a brief period, providing plenty of power to run the camera mechanism. (Since, in that camera, the battery had to power the mechanism that squeezed the film between the development rollers, substantial power was required for about one second.) The battery chemistry wasn't rechargeable, although there's no reason a rechargeable chemistry couldn't have been put in that packaging.

PolaPulse batteries are still available, and turn up now and then when a flat battery with a high peak current is needed. One amusing use of PolaPulse batteries is StartMeUp, which is a pocket-sized unit with six PolaPulse batteries used to restart a car.

Several other manufacturers claim to make flat batteries, some of which are rechargeable. However, none of the manufacturers mentioned in that article actually seem to be shipping product.