Power Play

LTA, BALLOONS, USA, CIVIL WAR, LOWE, GAS GENERATORS & COOLERS by public.resource.org, on Flickr
Image courtesy of the Smithsonian Institution.

Mobile device manufacturers have made some incredible innovations in the past few years. It is even more fantastic when you consider that they have been working behind a major roadblock for the past decade. While microprocessors, radio receivers and transmitters, hard drives, RAM, LCD screens and other mobile device components have been getting steadily smaller and at the same time dramatically improving their performance, once particular component has basically stagnated: the power source. Now the largest, heaviest, and often most expensive part of your mobile device is the battery, without a dramatic revolution in power technology mobile devices may been coming up on an innovation wall. But there may be hope.

Today, all mobile devices use a system of power storage to fuel the power needs of the device. traditionally, this comes in the form of batteries. The first of which, the Alkaline battery, wasn’t rechargeable so they had to be replaced periodically. The first popular cell phones, used NiCd batteries. These had the advantage of being rechargeable, but the total amount of power that could be stored was low and they had a tendency to rapidly drop off the amount of power they could provide over extended use. almost every modern mobile phone now uses a lithium-ion battery. these are more environmentally friendly than the NiCd and they could hold far more power and didn’t have the same power drop off over time. However, lithium-ion technology has basically stalled over the past decade. the only innovations on the horizon amount to faster charging times, rather than significant performance or size improvements. Even alternatives batteries don’t expect to gain much in terms of performance.

Many of the most intriguing possibilities for mobile devices is in the area of power generation as an alternative to power storage. Historically, even at the largest scale electrical power has always been generated by one of three means. The most common is the electrical generator which produces power from mechanically turning a magnetic field around an electrical circuit. This concept is the source of electricity from everything from hydro-electric damns, wind farms, nuclear power plants, and coal and oil burning plants. Currently, this type of power generation is far too bulk and heavy to fit inside a mobile device. More recently, photovoltaic or solar cells have been used to directly convert light into electrical power. For land-based power generation this has promise, but the surface area required and the inability to generate power at night or in cloud cover makes is unsuitable for mobile use except as a way to recharge. Finally, thermoelectric power, in a manner similar to photoelectric, directly converts changes in temperature to electrical power. This technology is currently only feasible for use in space vehicles. Mobile devices will need to innovate in other directions.

Many of the most intreaging possibilities for mobile devices is in the area of power generation as an alternative to power storage. Historically, even at the largest scale electricall power has always been generated by one of three means. The most common is the electrical generator which produces power from mechanically turning a magnetic field around an electrical circuit. This concept is the source of electricity from everything from hydro-electric damns, wind farms, nuclear power plants, and coal and oil burning plants. Curently, this type of power generation is far too bulk and heavy to fit inside a mobile device. More recently, photovoltaics or solar cells have been used to directly convert light into electrical power. For land-based power generation this has promice, but the surface area required and the inability to generate power at night or in cloud cover makes is unsuitable for mobile use except as a way to recharge. Finally, thermoelectric power, in a manenr similar to photoelectric, directectly converts changes in temperature to electrical power. This technology is currently only feasible for use in space vehicles.

Mobile devices will need to innovate in other directions.

Kinetic power or the power of movement has actually been around for hundreds of years, at least in mechanical form. Self-winding watches that use the movements of the wearer’s own were first invented in the 1700’s. Imagine if you could power your cell phone simply by walking around with it. recent research in Nanogenerators makes that at least a theoretical possibility. In this scenario, hundreds or thousands of tiny electrical generators would respond to changes in the direction of gravity or momentum by generating a small electrical current. While each nanogenerator’s output would be very, very small, added together they could generate relatively significant voltage.

Another alternative would see your own body become the actual power source for your cell phone. At the simplest level, this could turn you into the equivalent of the two-potato clock. More promising is the research by Max Donelan who believes it may be possible to capture biomechanical energy directly from the movement of your joints. A special strap around the knee was able to generate enough power to fuel 5 cell phones. Even more revolutionary would be to use biofuel cells which can actually extract electrical power from the sugar in your blood. While currently this is only intended for implanted devices, such as pacemakers, it is not outside the realm of possibility that it can be modified to work from skin contact or through contact with cyborg-like external implant.

Considering the basic nature of mobile phones, it’s a wonder more advances haven’t been made in harnessing the power of sound itself. Sound waves are not too much different from ocean waves, and both can be used to generate electrical energy, although with sound the output has always been much smaller. Sound powered telephones are actually nothing new, they’ve been in use in Navy ships and closed-circuit telephone systems, such as with road-side assistance or ski lift phones. However, recent scientific discoveries have the potential to allow a phone to generate power through the simple act of talking into it. theoretically, it could even leave the microphone on to power itself through ambient noise too.

Finally, is there really a need to put a power source into a mobile device anyway? Can’t we just beam the energy there over the air? Technically, wireless energy transfer as been possible for some time, but traditionally the possible modes of achieving it, through laser or microwaves or limited in range such as with near field technologies has been problematic for general purpose mobile devices. However, thinkers and scientists are dreaming up new ways to transfer power over the air. More problematic might be areas, such as inside an airplane where wireless energy may not be feasible.

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