For decades, we’ve focused on making technology faster and more capable. Now, as we power through the 21st century, we are realising our future lies in micropower.
You have been using miniaturised power sources for decades, and it’s likely you haven’t even given it a second thought.
Our chief small source of power for much of the 20th century was the humble alkaline battery we put in TV remotes, Sony Walkmans, and just about every wireless device in our lives. Then, as devices requiring much more energy for a longer amount of time began to trickle into the consumer market – particularly the early generations of mobile phones and laptops – a row of AA and AAA batteries simply weren’t going to cut it anymore.
That’s why the lithium-ion rechargeable battery that we’ve all come to know (and loathe, in some cases) came onto the market in 1991, with Sony’s mobile phones leading the charge.
Now, 25 years since the first commercial lithium-ion battery, the technology is found in devices you likely use on a daily basis –whether it’s a smartphone, laptop, smartwatch or even an electric vehicle or e-cigarette – but this power is far from everlasting.
Last year, industry experts expressed their concerns with regard to mining lithium, asking whether we were nearing “peak lithium”, with supplies expected to dwindle from here on in.
A US Geological Survey report released last year suggests we wouldn’t run out of lithium for another 365 years, but lithium-ion power sources also rely on a chemical compound formed using cobalt, which comes with its own ethical issues. Both Amnesty International and Afrewatch are calling on multinational companies using lithium-ion batteries in their products to investigate whether the cobalt they’re using is extracted under hazardous conditions or using child labour, and to be more transparent about their suppliers.
All of these factors have driven industry and researchers to explore not only alternatives to lithium-ion batteries as a method of energy storage, but also technology that can use a battery’s stored energy much more efficiently.
More than Moore
For more than 50 years, the amount of energy needed to power the internal microprocessor of all of our devices has been guided by an industry standard referred to as Moore’s Law.
Named after an observation made by Intel co-founder Gordon E Moore in 1965, Moore’s Law foresaw that the processing capabilities of semiconductors and chips would double in capacity every two years, thus enabling years of shrinking computer components.
However, thanks to the latest in technological progress, the smallest chip manufactured today measures 14 nanometres across. By following Moore’s Law, this would decrease in size to between two to three nanometres within a matter of years. By this point, the chip would be completely unreliable in terms of performance and energy capacity and so, earlier this year, Moore’s Law effectively became a retired standard as the semiconductor industry rather unanimously agreed to discontinue the model in favour of ‘More than Moore’.
This is now encouraging chip manufacturers and energy experts to look beyond making chips smaller and, rather, look to making the current generation more efficient and powerful.
To quote Aidan Quinn, head of materials and devices at the Tyndall National Institute in University College Cork: “If the 20th century was all about speed and performance, the 21st century is all about lower power and mobility.”
Smart cities need smart power
Of the 38.5bn connected devices that it is estimated will be surrounding us in less than five years’ time, many of these will be minute sensors used as data harvesters for multiple sectors, particularly as the concept of smart cities is further developed.
As the director of IBM Research Ireland, Dr Eleni Pratsini, explained in conversation with Siliconrepublic.com, the sensor-ridden cities of the future will be able to provide much more accurate live information on traffic flows, pollution and public transport to city planners. You can already see innovations like this in action in places such as Singapore, with its stunning and powerful ‘supertrees’ acting as giant, bio-harvesting data generators.
Just as we dismissed the idea that mobile phones should rely on replaceable alkaline batteries, the same goes for using inefficient lithium-ion or direct power supply devices for these smart city sensors. Yet the question still remains of how to make these various miniature connected devices more energy efficient.
The answer, of course, is magic. At least, that’s the affectionate nickname given to integrated magnetics by those working with this cutting-edge technology.
The magic chip
As far as commercial manufacturing is concerned, the ‘holy grail’ is a microprocessor that is not only powerful and energy efficient, but requires the least amount of physical space within a device as possible. In smartphones, for instance, every single millimetre within them has been painstakingly designed by a company’s engineers to try and cram as much hardware as possible into a thin and attractive shell.
Every action that a phone undertakes – be it lighting up the display, launching the camera, or running a game – requires a different voltage, all within a power management chip (or PMIC, as it’s commonly called) that contains a number of semiconductor power switches turning each of these processes on and off. Within these, you then have a multitude of minute components that take up valuable real estate, including a magnetic component used to store energy in the output of a power supply.
With this in mind, Prof Cian Ó Mathúna, head of strategic programmes at Tyndall, has been working on what might be a perfect representation of the shift towards ‘more than Moore’ using integrated magnetics.
A white paper on this research is to be published in April, and it poses the question: what if we could remove those magnetics from the circuit board, or those discrete components, and strip away a lot of excess silicon?
Essentially, Ó Mathúna and his team want to take all of the power management and place it on top of the system on chip, otherwise known as ‘power supply on chip’ (PwrSoC). The challenge, then, is making magnetics small enough that you can fit a number of them on top of a microprocessor chip.
A typical magnetic-core inductor involves a wire coiled around a ferromagnetic material, which Ó Mathúna describes as “a bulky component”. Air-core inductors, which can be empty at the core, are less so, but having a magnetic core can increase the inductance of a coil up to a factor of 10. And so, Ó Mathúna has found a compromise for an integrated magnetic solution based on research carried out over the last 20 years.
“An alternative way of doing it is if I could borrow some of the disk-head industry’s thin-film magnetic core processing that it’s been using for 30 years in huge volume production,” he said. “I could borrow those magnetic materials to make myself a very small footprint inductor and it would have much better performance than the air-core device.”
Using this, he would hope to make the magnetics for the inductors in those power supplies disappear onto the silicon that is the microprocessor.
Having already held a number of discussions with major manufacturers, Ó Mathúna said that it’s likely that the first product featuring ‘magic’ will be on the market in the next two to three years.
It’s a natural progression for battery technology in an age where immensely powerful products are drastically slimmed down.
“Battery tech has not kept pace with consumer’s needs,” said Ó Mathúna. “In terms of efficiency and form factor, what’s driving consumer devices is ‘thinner is better’. Integrated magnetics takes a large number of the large, bulky, passive components off, so you are able to make a thinner, lighter device, and that’s important for things like wearables.”
The next step for his team, and those working on integrated magnetics in general, will be to investigate other available materials such as glass, which was recently demonstrated as a storage medium capable of holding data for billions of years. And if that sounds too much like science-fiction, consider then that micropower may one day be found within the human body itself.
From the smartphone to the human heart
When fantasists and futurists envision a future where humans become half-human, half-machine (cyborgs, if you will) the question of how to power such possibilities is rarely raised. Yet in labs across the world – and in one particular institute in Cork – there are teams that are, in fact, creating electronics powered by the human body.
MANpower is a system developed by Dr Alan Mathewson, head of circuits and systems at Tyndall’s Micro & Nano Systems Centre, which aims to turn naturally-occurring activities in the human body into a means of generating electricity for a pacemaker, all within a tiny capsule.
Using the power of vibrations at 25Hz created by the beating of the heart, a 2cm tube can power the pacemaker indefinitely, for as long as the person has a functioning heartbeat.
“When we first started the project, we thought we were going to get a [demonstration device] out of it but now we’re comfortable there will be [a usable one], and it will all fit in the titanium tube,” said Mathewson.
This technology can also be used alongside other common medical devices such as stents, which are small mesh tubes used to treat the narrowing, or stenosis, of blood vessels. In some cases, these vessels can narrow again even after treatment with a stent, which is known as restenosis.
Currently, patients with stents and medical staff can’t rightly tell if pain is being caused by an issue with the stent or a plaque build-up. However, using a sensor to detect plaque, powered by MANpower technology, a medical team would be able to determine what is causing an issue with the patient.
“We built [a sensor] which would enable us to detect restenosis in blood flow, but that [flow] would be the power supply,” explained Mathewson. “So you have to have flow to drive the sensor when it was actuated.”
Power harvesting post-silicon
It’s certainly no walk in the park for Mathewson and the other researchers working on this technology, as even choosing the right material to make the energy harvester has had its complications.
“One of the challenges of making an energy harvester is that most of the materials that you make are brittle and very stiff,” he said, referring to silicon, in particular. That’s why the MANpower harvester uses the much more flexible – but less powerful – polymer, which includes the vibrational cantilever, the element that generates energy through vibrations.
The next step, Mathewson said, is to boost the technology’s performance using alternative materials, specifically referencing scandium-doped aluminium nitride, a material that will give you much better performance at the same thickness as polymer.
Nanorobots and personalised medicine
Yet this is not where micropower in the body ends. There are other solutions that will likely lead to a future of advanced personalised medicine, or even nanorobots inserted into the bloodstream, harvesting energy from the ebb and flow of blood within an artery.
“The good thing about an electronic device in the blood flow is it leads to things like personalised medicine, so you could build sensors into the blood flow and test the effectiveness of drugs, or you could actually tailor drugs to a specific person,” said Mathewson.
Incredibly, like Ó Mathúna, Mathewson said that the technology he, his team and many other researchers are developing is not exclusively for distant future generations. Rather, it’s one that we could encounter within the next decade or two, as the number of people researching micropower has increased substantially in the last few years alone.
Indeed, by the time this technology has reached the point where it’s affordable and mass-produced, the divide between human and machine may have become increasingly blurred as sensors placed throughout the human body will see us living as giant batteries for the micropower generation.
Electromagnetic coil image via Shutterstock
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