Battling with Batteries as IoT Technology Scales
April 10, 2023

The value proposition for batteries as “portable power” has made them a highly effective resource for decades, especially for use in electronic devices where wired power is not an option. While obviously convenient for legacy consumer products like television remotes and toys, batteries have also been useful in recent decades for connected endpoints like sensors and transmitters as our need for these IoT devices expands. Thanks to their size and portability, coin-cell batteries have been instrumental in the deployment of millions of sensors and transmitters into places where wired power can’t go.

Batteries are far from a power panacea for the exploding wireless electronics category however, as they introduce a variety of troubling downsides for product designers, including power delivery style, replacement-related challenges, and a shocking volume of waste. Though vast “trillion sensor networks” are projected as the next step for the IoT, device designers will struggle to meet this mark unless we move away from batteries and towards a more sustainable, scalable power solution. That’s exactly what WePower has achieved with our Gemns Energy Harvesting Generators (EHGs).

The Explosion in Small-Scale Wireless Device Production

Put simply, sensors and data transmitters are everywhere. Every modern car has dozens of sensors, every home has hundreds, and every building has potentially thousands. The patented WePower line of Gemns EHGs is designed to serve applications in each of these settings, along with countless other markets.

Driven “in response to rising automobiles and machine production,” and, “an inclination towards digitalization and process optimization” in the private and industrial sectors, the market for these small-scale devices has exploded in recent years to a size of $204.8 billion in 2022, per Precedence Research, with an expectation that it will grow beyond $500 billion within the next decade.

Essentially, as our world’s capacity to process and act on information improves, our infrastructure for gathering and transmitting information must keep up. Right now, it can’t, and batteries are one of the biggest reasons why.

Though their portability has long been invaluable, batteries bring a number of significant drawbacks. In order of escalating severity, those issues are with regard to power delivery, replacement-related challenges, and waste.

A Clash Between Power Supply and Demand

Batteries perform best when they can provide power in long, low, continuous levels. This contrasts with how wireless devices like sensors and transmitters prefer to consume power. These devices require short spikes of power when they execute their actions but otherwise can remain mostly dormant. This clash of styles between battery power supply and device power demand means devices don’t perform as well as they could, and batteries run out far faster than expected.

Replacement-Related Issues

Once batteries die, device owners need to replace them. That requires device designers to include user access into the device as part of their plans, as well as features to alert or remind owners when batteries need replacement. Many simple devices like sensors or transmitters forgo these features, leaving owners to remember for themselves when their batteries will die (which of course will be far sooner than they expect). This can have serious consequences.

To illustrate, consider your water leak detector if you have one (which you probably should). Often placed under sinks, washing machines, or toilets, or tucked away in dank, dark basements, these sensors play a vital role in the health of your home or facility and are meant to inform you whenever there’s an issue. Typically powered by batteries, water leak sensors become useless when their batteries die, leaving you vulnerable to costly leaks that can lead to mold or fungi, the ruin of documents, devices, or furniture, and even the breakdown of the building’s structural integrity.  Since the sensors typically transmit only when there is an alarm, the absence of an alarm is ambiguous, potentially signifying a dead battery or no leak.

Staggering Waste

While failure to replace batteries in a timely manner can be viewed as an individual problem, the successful replacement of batteries is a global one. Each year, Americans throw away more than 3 billion batteries, totaling 180,000 tons of hazardous waste, according to environmentalist groups. According to EnABLES, an EU-funded project whose mission is to “make batteries outlive the devices they power,” nearly 80 million batteries powering IoT devices will be discarded every day by 2025, if no alternatives arise. That number is even greater according to Mike Hayes, head of ICT for energy efficiency at the Tyndall National Institute in Ireland, who projects that, “in the trillion sensor world predicted for 2025, we are going to be throwing over 100 million batteries everyday into landfills” unless we find a longer-lifespan solution.

An Alternative Solution to Batteries

To meet IoT device deployment projections, reap the benefits of this sprawling connectivity, and capitalize on a massive market, we must find a way to sustainably power trillions of wireless endpoints. Simply designing batteries with longer lifespans is one option, although that will still end with dead batteries in landfills. Rechargeable batteries are another option, though this simply swaps maintenance for replacement; the owner still has to do something. In both of these cases, the issues of power delivery style and device design constraints go unaddressed. To truly address the trio of problems presented by batteries to wireless devices and their designers, we need to move onto a new method of power supply. Fortunately, the energy we need is already available all around us.

Kinetic Energy Harvesting

As solar panels, wind turbines, and hydroelectric dams prove, energy is available for us as long as we have the technology to capture it. At the small-scale device level, the sun, wind, or water require too much infrastructure to provide enough power at the low target costs and small sizes required, but we can rely on something else: motion.

Instead of sun, wind, or water, the patented WePower energy harvesting process involves electromagnetic induction wherein a kinetic force, like the push of a button or the roll of a wave, moves a small magnet through a metal coil. In adherence to Faraday’s Law, this action creates an electromagnetic charge, which is enough to power a data transmission. The more efficient the energy capture and conversion, the larger the charge. The larger the charge, the greater the range, reliability, and functionality of the data transmission.

WePower has designed our proprietary Gemns EHGs to harvest energy more efficiently and produce an energy output measuring in the millijoule range, which at least 40 times more than other kinetic energy harvesting technologies producing energy outputs in the microjoule range. Our higher energy output can enable greater RF range and reliability, larger packet sizes, longer message length, increased I/O capability, increased microcontroller functionality, and the possibility for bidirectional operation with computation at the edge.

Energy harvesting is not necessarily a new concept to the wireless device industry but innovations in electromagnetism, microelectronics, power conversion circuitry, and nano- and pico-power technology have only recently reached the point where kinetic energy harvesting components represent a viable alternative to battery power for small-scale IoT devices. Their reliance on their surroundings means they don’t need recharge or regular replacement, and their lifespans can last millions of activations. In fact, Gemns EHGs have been tested for up to 1 million actuation cycles of durability and can easily be adapted in design to suit application-specific requirements for packaging integration and energy requirements.

We have a long way to go before batteries are phased out from our IoT devices, but if we want to speed up deployment, we need to strip out the things holding back device performance, design, and sustainability. That means saying goodbye to energy from batteries and instead sourcing it from the devices’ own surroundings.

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