What is piezoelectricity and how does it work

What is piezoelectricity

Piezoelectricity can be described as the electric charge that accumulates in certain solid materials when mechanical stress is applied to it. Solid materials which show the piezoelectric properties are crystals, certain ceramics, and biological matter such as bone, DNA, and various proteins. The word piezoelectricity means the electricity which results from pressure and latent heat. Piezoelectric energy generation is the generation of energy from ambient movement or vibration. It can be considered as a micro-scale process because the generated energy is very small. Piezoelectric materials are used to convert mechanical pressure into electric energy and it can be amplified for use. The piezoelectric effect is reversible process materials that exhibit the piezoelectric effect also exhibit the reverse piezoelectric effect. Ultrasonic sound waves are produced by the help of an inverse piezoelectric effect. Piezoelectricity means pressure electricity, the generation of electricity is done by applying pressure. Piezoelectricity can be observed if mechanical stress is applied to a solid by bending, twisting or squeezing.

Who discovered piezoelectricity

Piezoelectricity was discovered by Pierre curie and paul Jacques in 1880 both of them where French scientists. Generating an electric charge in a material when subjecting it to applied stress, and conversely generating a mechanical strain in response to an applied magnetic field.

what is a piezoelectric transducer

What causes piezoelectricity can piezoelectric materials generate electricity

The solid materials which exhibit piezoelectric properties include crystal, in crystals or in other solid materials the atoms are closely arranged and can move slightly. Piezoelectric crystals are electrically neutral, the electrical charge inside these crystals are balanced. So if we apply pressure to this crystal it would change the structure and it would result in changing the position of the atoms, which would affect the balance of positive and negative charge which would create a net electrical charge. This will occur for the whole crystal, thus the positive and negative charges appear on opposite outer faces of the crystal. When a voltage is applied to a piezoelectric crystal the atoms inside it will be subjected to electrical pressure. So in order to rebalance themselves, they have to move and that’s why when a voltage is applied piezoelectric crystal will deform.

How piezoelectricity works

During normal conditions, the charges in piezoelectric materials are balanced even if the material is not symmetrically arranged. Opposite charges cancel each other thus there won’t be any net charge in the crystal. If mechanical stress is applied to the crystal surface the charges won’t cancel each other and there will be a net positive or negative charge on the crystal. Then a voltage will be produced on the crystal surface and it is called piezoelectricity.

What is piezoelectricity used for

Piezoelectricity is used in many places some of them are production and detection of sound, piezoelectric inkjet printing, generation of high voltages, electronic frequency generation, microbalances, to drive an ultrasonic nozzle, and ultrafine focusing of optical assemblies. It can also be used for scanning probe microscopies, such as STM, AFM, MTA, and SNOM. It is also found in everyday uses such as acting as the ignition source for cigarette lighters and it is also used as the time reference source in quartz watches. Piezoelectricity has become an innovation motor. Piezoelectricity is for many technical applications, it is widely used in the field of information and communication, industrial automation, medical diagnostics, automation, and traffic control and in the defense industries.

How to do energy harvesting with piezoelectricity

We can make a small amount of energy by pressuring the piezoelectric crystal once, so if we do this to many piezoelectric crystals more than one time we could create a lot of energy. Piezoelectric roads are an example of this when a vehicle passes over a road the road deflects vertically and these vibrations are released as thermal energy which is being wasted, by using piezoelectric generators in the roads we can convert the vibrations caused by the vehicles into useful electricity. It is constructed by certain layers, the first layer is laid with fine gravel and sand content. After that an asphalt layer is laid to give a strong base for generators, piezoelectric generators are placed in quick-drying concrete all the generators are wired in series to get collective output. Electrical energy is stored and transferred and then it is charged into the battery on one side of the road and from there it is distributed. So we can generate energy by the piezoelectric materials, we can generate electricity from foot traffic, road traffic…

Power generating sidewalks charging pads under the crosswalk collect energy from vibrations, vibrations caused from gyms and workplace can be used to generate the energy, power generation can also be done by placing the crystals under the floor mats, tiles, and carpets. It can also be placed under the dance floor, so when people use the dance floor lot of voltage is generated.

What are the advantages of piezoelectricity

  • It is unaffected by external electromagnetic fields
  • Pollution-free and low maintenance
  • Easy replacement of the equipment can be done
  • It can be used at any remote place
  • The centralization of power is minimized
  • Cheap source of electricity generation
  • Generates a large amount of electricity
  • It does not require large space or operating system for generating electricity

What are the disadvantages of piezoelectricity

  • It cannot be used for truly static measurements
  • It can pick up stray voltages in connecting wires
  • Crystal would crack if overstressed
  • It would get affected by long use at high temperatures
  • It needs constant inspection
  • Maintenance is difficult

What are the applications of piezoelectricity

Piezoelectric devices are widely used in industrial and manufacturing units, it is also used in the automotive industry, it is also used in medical instruments and in information and telecommunication.