Cellphone charging using piezoelectric crystal?

[Qwertyuiop23]

A project that I am carrying out for my Extended Essay (part of the International Baccalaureate Diploma), involves me using a piezoelectric crystal to generate power in order to charge an auxiliary battery which charges a cellphone battery (auxiliary battery an attempt to reduce wear on cellphone battery). The crystals I am using I have got from BBQ lighters. The trigger mechanisms in these lighters produces a spark that can jump roughly 2-3cm in air, and the electricity is generated from the piezoelectric crystal.

I would like to know whether using one of these would generate enough current to actually charge the cellphone battery? I have tried wiring four of these mechanisms together however, they do not produce a longer spark but rather just a more intense spark.

So I would like to know whether these trigger mechanisms will be enough to generate enough electricity to charge a cellphone battery. I think the voltage will be enough but I am not sure about the current side of the charging so if someone could also inform me of this it would be greatly appreciated!

Just a note these triggers will be pressed about 1-2 times per second.

The crystals I am using are meant for high energy single point release. So I would need to store the current released in a capacitor to store the charge and add a circuit to regulate current.

Is there a way to get a current that is being produced in a single-point release converted into a continuous output current?

If it would work I am a little unsure on how to go about wiring one of these circuits up and how simple it will be. Even a circuit diagram would be helpful!


Cheers
Lance

 

[Nigel Goodwin]

Sorry, a completely pointless idea - the amount of energy from a piezo is miniscule.

For a start try measuring it!.

 

[Qwertyuiop23]

Hence why use a capcitor/rechargeable battery to store that energy. And I have ten of them all wired together . . . ?

 

[Nigel Goodwin]

Hence why use a capcitor/rechargeable battery to store that energy. And I have ten of them all wired together . . . ?

Ten times nothing is still nothing - like I said, measure the output - feed it through a diode to a capacitor, with a multimeter across the capacitor to monitor the voltage increase (if any).

 

[audioguru]

In addition to the problems that the current from a piezo lighter is almost nothing and its duration is also almost nothing, the voltage is far too high to be of any use.

 

[crutschow]

One of the significant problems is that the spark is very high voltage and very low current. You would need some method to efficiently convert that to the low voltage and higher current needed to charge the battery. It would require storing the spark energy using a high voltage rectifier and capacitor. Then using some type of high voltage buck converter to generate the required charging voltage. That is not simple or cheap to do.

But as also noted, the energy from the spark is quite low and it's unlikely that you could charge the phone with any reasonable number of piezoelectric elements.

 

[ronv]

Not much there, but not nothing either.
They work better where the frequency is higher.
Power Walking | Popular Science

 

[antknee]

You can think of a piezo as a capacitor for testing purposes. In that case:

I=2ΠFCV

Ergo to increase the current you can chose a piezo with a higher resonant frequency, or you stack them to increase the capacitance.

I would like to know whether using one of these would generate enough current to actually charge the cellphone battery?

The answer is no.

 

[BobW]

What hasn't been mentioned is what will likely be an extremely high mechanical failure rate if you intend to actuate this things twice per second. They simply weren't designed for continuous use.

If you're determined to carry through with this, then I suggest that you look at piezo audio transducers to harvest power from ambient noise. I've seen a webpage where someone's done this and has managed to get meagre (but measurable) amounts of energy this way especially in very noisy locations. Can't remember the URL, but a google search may find it.

Edit: Found the link:
https://www.electro-tech-online.com/custompdfs/2010/07/6541379.pdf
Starts at the bottom of page 94.

 

[audioguru]

The article about the piezo buzzer used as a generator talks about powering a wearable device which might be a low current watch. A cell phone uses thousands or millions of times as much current.

Maybe a medium size windmill generator or solar panel will help extend the life of the charge of a cell phone battery.

 

[BobW]

Yes. I wasn't trying to imply that it was necessarily a practical solution, but the idea could be expanded to a large array of piezo transducers and harvest a bit more energy.

 

[audioguru]

It is impractical to use a large array of piezo transducers with their many wires all over the place and large size. To power a low current watch?

 

[ronv]

Module

What I found interesting about that article was that someone (ALD) actually makes a device to harvest such low power signals. What do you suppose the use is?

 

[walcellularllc]

I did not know this was possible

 

[ronv]

Fully integrated energy harvesting wireless sensors have been developed for the helicopter control rod, or pitch link. Piezoelectric materials bonded directly to the pitch link were used to harvest strain energy for operation during flight. This work demonstrated, for the first time, that an energy harvesting wireless sensor for rotating helicopter components could be operated indefinitely, using only the strain energy of operation for power.

 

[dknguyen]

Isn't that just an alternative to an alternator? It still requires energy the heli's primary powerplant.

 

[Nigel Goodwin]

Isn't that just an alternative to an alternator? It still requires energy the heli's primary powerplant.

Of course - but I suspect the amount of energy both taken and generated was small?.

 

[dknguyen]

I know that. I was more curious about whether it was lighter, more reliable, or more efficient than the alternator or hydraulics or whatever other method is normally used to siphon off engine power in order to power the control links.

 

[transistor495]

I'm wondering why you people are not thinking about a simple solar energy harvester instead? The charge required to run a quartz watch is pretty small and a small panel with a rechargeable button cell will make the watch run for many many years without any assistance. Think about the steps needed to do it by a piezoelectric electric technology.

Instead think about a way to increase the efficiency of a solar panel device. If we can achieve almost a whopping 80+% efficiency(currently only 40% max), then keeping the panel mounted cellphone inside the house with normal daylight conditions is enough for working it continuously.

I don't think piezoelectricity will emerge as an efficient AE idea in any future.

Paralleling hundreds/thousands of piezocrystals that mounted under the footpath sounds funny. Hammering a giant piezocrystal for hi.power generation is a joke.

 

[ronv]

Data Loggers

Found this. I suppose besides the slip rings it would still be hard to get power to the links. I think it is to monitor the health of the system. I suppose with a hammer that big you can get a few micro watts. Not going to replace Hoover dam that's for sure.