Beyond calculators: Sustainable solar for IoT devices

Beyond calculators: Sustainable solar for IoT devices

Interviews |
By Jean-Pierre Joosting

Our society relies on an ever-growing number of connected devices. Data collection and transmission surround the individual every second. All devices need energy, and a well-established technology is ready to be the sustainable alternative to primary batteries. In this short article, Robert Spiegler, Senior Product Manager at Panasonic Industry discusses solar as an alternative to batteries in IoT applications.

In our connected society, the usage of IoT devices increases rapidly every year. All devices share a common trait: they need electricity. So, billions of devices use primary batteries that need changing and recycling. The German Federal Office for Environment (Umwelt Bundesamt) states that in 2021 over 257.000 tons of used batteries were collected for recycling. That’s an increase of almost 13% compared to the previous year. But recycling primary batteries is very cost- and energy-consuming. Besides the ecological factor, also maintaining battery-powered devices is a cost factor. Primary batteries have to be replaced regularly, which is always time- and cost-intensive especially when the sensor systems are not easily accessible and reliable system availability is required. 
To reduce the usage of primary batteries, and therefore save energy, resources, and costs, Panasonic Industry has increased the Amorton (Amorphous Silicon Solar Cells) product range. Having over 20 years of experience with this technology, the company targets new fields of applications that can be powered through Amorton technology.

Almost everybody is familiar with a solar-powered calculator, watch or remote control. But Amorton has the potential for a much wider range of applications: even under weak light conditions or indoors, the amorphous solar cells harvest energy and can be used as a power source for many applications besides wristwatches or calculators.


Robert, how does Amorton work?

Compared with crystalline silicon cells, Panasonic Industry’s amorphous silicon solar cells, called Amorton, have a much higher absorption coefficient in the visible spectrum of 380nm to 740nm. Because of a thickness down to 180μm, and depending on the requirements, Amorton cells are available on two different substrates: flexible plastic film and glass. This enables us to design complex shapes and forms, even bent solar cells are possible.

Unlike the fabrication method used with crystalline silicon solar cells, multiple Amorton cells can be simultaneously connected in a series, so it is possible to create cells with a variety of voltages. The result is that our amorphous silicon solar cells are suitable for energy harvesting in low light conditions (starting from a few lux) or artificial light such as LED lighting or fluorescent lamps. At the same time, Amorton cells are thin, shock-resistant, lightweight and can be flexible. To achieve the most efficient solution, it is also possible to cluster different types of Amorton cells.


What fields of industries already benefit from the Amorton technology?

Harvesting energy from artificial light sources indoors or under tough conditions outdoors opens a wide variety of applications, that directly benefit from the maintenances-free and long-lasting technology: combined with secondary batteries, hybrid or supercapacitors as energy storage, communication devices, sensors, wireless nodes, security devices, electronic shelf labels, wearables, remote controllers or tracking systems can be powered. So, depending on the light conditions and the demand for energy, Amorton can be the solution as a sustainable source of power.


What advantages do you see in using an Amorton-powered device?

The upside of using solar-powered IoT devices is quadruple: sustainable, cost-effective, secure and system availability.

Obviously, a solar-powered device does not rely on primary batteries. So, running it prevents the usage of batteries and produces less waste. But I also have to mention that thin film cells only require very little silicon in the low-energy production process.

The second benefit is that a solar-powered device operates without downtime, given sufficient exposure to a light source. When manually changing the batteries on a device, this device does not run and often needs to be set up or adjusted. Also, changing batteries is labor-intensive, especially when we think about devices that are operating remotely or in places that are difficult to access. This is time-consuming and increases the running costs of this device.

But besides the ecological and economical upsides of utilizing amorphous solar cells, security is not to be forgotten. Obtaining, for example, the sensory inputs of a security device are crucial. And the availability of a solar-powered system or device is not interrupted due to an empty battery.


Where do you see the potential for the Amorton technology?

The potential of this technology is extremely wide. It can be as simple as a LED night light, where amorphous solar cells harvest the energy during the daytime and provide the power for a LED that illuminates a room or staircase at night.

Because of the low weight and flexibility in shape, the design of wristwatches or any other wearable is not compromised by integrating our amorphous solar cells. It is extremely exciting to work with the engineers and designers of our customers to achieve elegant and sustainable solutions.

One last, great example where the Amorton technology shows its potential is the monitoring of farm animals. Via a cattle tracker the activity and essential health information of every animal are conducted and can be analyzed by the farmer. Effective adjustments of feed or early information about possible health issues lead to increased well-being of the life-stock and overall to more productive farming.

Robert Spiegler has 10 years of experience in product management and application engineering. His previous responsibilities as new Business Development Manager at the European Central Laboratory paved the way for new business opportunities and products. He is now head of product management for the Solution Products Business at Panasonic Industry Europe.


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