Super capacitor phone battery

[James Matheson]

Hi this should be easy to answer and worth billions to the right person
I need a super capacitor cellphone battery

Heres my video

Please tell me.who can and how much

 

[Alec_t]

A supercap would be totally unsuitable for powering a standard cell-phone, since (a) its voltage drops steadily as it discharges and (b) it has relatively high internal leakage current which severely limits its standby-time.

 

[James Matheson]

I am not asking how not to make it work, i am asking how to make it work,

 

[Alec_t]

I think you are going to be disappointed. If there were a practical, cost-effective solution, the phone manufacturers would be implementing it already.
There are only two approaches that I can see:
1) Build a boost converter that would cope with the cap's dropping Volts by running from the cell-phone's maximum voltage (Vmax) down to close to zero Volts while outputting a constant Vmax .... (challenging).
2) Re-design the cell-phone to run from that range of voltage ..... (impractical).

 

[BobK]

The voltage drop is not the problem, a boost converter takes care of that. The problem is that the energy density of supercapacitors is way lower than that of a lithium ion battery.

Bob

 

[Alec_t]

Good point.

 

[Doug3004]

Supercaps sound intriguing but the high ESR that they have prevents using them in most of the ways that other capacitors get used. Have any of you guys seen any in-circuit use of them yet?

The China ones aren't too expensive to play with {to blow up, that is }. As usual with cheap China parts, they may not exactly hit their advertised values, but in youtube videos they appear to have way more capacity than any electrolytic the same size.

I've not bought any however because I haven't run across any need for them. The main things I've heard of building is the vibrating bug bots/brush bots.

 

[davenn]

Have any of you guys seen any in-circuit use of them yet?

Super caps have been used in circuits for many, many years as short term back up for holding system memory settings during short term power failures/battery changes etc

 

[BobK]

Supercaps sound intriguing but the high ESR that they have prevents using them in most of the ways that other capacitors get used. Have any of you guys seen any in-circuit use of them yet?

This is true of some supercapacitor, but others have extremely low ESR and very fast charge and discharge rates. There are products out there that use supercapacitors to start a car, providing up to 200A for a few seconds.

Bob

 

[(*steve*)]

There are 4 basic problems to overcome:

1. First is the voltage (and the way it drops steadily during discharge) A boost converter, as stated earlier in this thread is a simple and effective solution.
2. The second problem is more tricky. Most supercaps have a very low maximum voltage (2.5V typically). If the boost converter can work to nearly 0V, then this is not a problem, but you must have charge control to ensure the cap doesn't get overcharged. If you have multiple caps in series to increase the voltage then you need to balance the voltages on the caps during charge and discharge. In addition you NEVER want a negative voltage on a capacitor of this type. This is technically more demanding, but it had been done in many ways. To achieve a maximum useful life, you want the method to be other than resistors across the capacitors! A series of what are essentially small DC-DC buck-boost circuits can do this in a highly efficient manner. Note that these same issues exist for batteries, however capacitors store more energy at lower voltages than batteries.
3. Total system weight and size. If weight and size are not an issue, then ignore this. However, batteries will be smaller and lighter for a given amount of stored energy.
4. Cost. If cost is no object, lucky you. Otherwise you will find that capacitors capable of the storage of the same amount of energy as a single battery will be far more expensive.

 

[BobK]

However, in labs, they have achieved density similar to lithium batteries using graphene supercapacitors. Somewhere in the next 5-15 years I expect to see supercaps start replacing batteries, just not yet.

Bob

 

[(*steve*)]

In 5 to 10 years will we also see some sort of improvement in battery technology too?

 

[ChosunOne]

(SNIPPED)

Cost. If cost is no object, lucky you. Otherwise you will find that capacitors capable of the storage of the same amount of energy as a single battery will be far more expensive.

I have to pick a nit here: The up-front cost of capacitors vs. batteries of equal energy storage is greater, but the cycle life of capacitors is orders of magnitude greater than any battery. I've seen typical promises of a million charge cycles, but we all know that plenty of capacitors have cycle lives longer than that. AFAIK, if treated well, capacitors are effectively immortal. So if you compare the cost of capacitors to the cost of all the batteries they will replace during their service lives, I believe the capacitors will turn out less expensive in the long run.

 

[Audioguru]

Graphene is used in Li-Po batteries today and it is an improvement over the old kind.

 

[hevans1944]

In 5 to 10 years will we also see some sort of improvement in battery technology too?

Possibly. But advances in chemistry can be a lot slower than advances in physics. When I finally realized that a supercapacitor is two high-valued capacitors connected in series, with the connection inaccessible to the outside world, it all made sense. Sure, you only get half the value of each capacitor, because they are connected in series, but half the value of a very large number is still a very large number. And this is ALL physics and geometry with almost no chemistry involved. So, yeah, I expect humongous improvements in energy storage density over the next five or ten years. Look at what has happened with chemical energy storage systems over the past one hundred years, explosives in particular, and compare that to improvements in battery storage systems over the same period of time. Virtually neck-in-neck IMO until the supercaps appeared on the scene.

The fact that nuclear weapons yield is measured in kilotons, or megatons, of TNT-equivalent explosive gives you some clue of what is possible with a really good understanding of physics. Heh. Atomic car batteries, anyone? Never requires a re-charge! Drive anywhere you like and never have to "flll 'er up" again! Put one of these puppies in your house to power up the "emergency power" inverter and never get another electric bill again! Build one big enough and you can use ion propulsion to do heavy lifting out of the Earth's gravity well. That should give NASA a badly needed boost into space without the mess of chemical rockets.

Oooh! Did I just hijack this thread about using supercapacitors to power cell phones?

 

[BobK]

I've seen typical promises of a million charge cycles,

Wow, at one charge per day, they will last 2739 years.

“Son, your great, great, ... , grandfather originally owned this supercapacitor.”

“But, dad, it’s only 2 megawatt hours, what good is that?

Bob

 

[NMNeil]

Check out the Youtube videos of Robert Murray Smith.
The jury is still out on whether it's a scam, but he has never asked for money and gives step by step instruction not only how to make his super capacitors but how to make the graphene.

 

[kellys_eye]

AFAIK, if treated well, capacitors are effectively immortal.

...and thereby lies the rub. Capacitors have been the most regular faulty component in many devices I've repaired over the years. The OEM would probably have sworn blind that they used 'quality parts' and the equipment would work 'for a lifetime'.

 

[davenn]

if treated well, capacitors are effectively immortal.

you cant be serious ?

Capacitors have been the most regular faulty component in many devices I've repaired over the years

yeah likewise .... one of the most unreliable components there is
and that come from 40 years of electronics servicing experience

 

[ChosunOne]

Guys, this is new information to me. I was going on my experience working with a large number quality PCBs that lasted for decades. The vast majority of the PCBs I replaced were for upgrades and new features, not because the boards malfunctioned. So my experience has been that electronic components in general are reliable, as long as they're not mistreated (Voltage surges/spikes, leaking water, overloading, shorting. etc)

Of the small number of boards that did malfunction, I never learned the actual specific causes--even in the 70's we Americans (specifically USA-ans) had developed a throw-away-and-replace rather than a fix-it economy for anything less expensive than a washer/dryer. So I was unaware of the most common PCB component failures.

I'm going to interpret this as capacitors being the least reliable in a category of very reliable components: Electronic components with no moving parts.

I'd like to hear your opinions on why capacitors are so relatively unreliable. Is it an inherent problem, or is it a matter of manufacturers chronically under-specing capacitors, i.e., not providing enough margin in the specs for anything that the cap might be subjected to? Or maybe not enough voltage regulation within the circuits? I'm having trouble believing that capacitors fail without some preventable cause.

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Getting back to the original question: At present, supercaps just aren't compact enough to use in cell phones. You might look into using supercaps for a portable cell phone charger.