Lighting up electronics redesign

The ENLIGHTENED project is an R&D collaboration between twelve companies and research organisations, funded by the EU Horizon Europe program. The focus is on increasing the potential of photovoltaic (PV) technology for low-power, low-light applications - combining energy harvesting and flexible, printed electronics to meet the power and energy requirements of small electronics across diverse application segments, while pushing the boundaries of sustainability in electronics design and production. ONiO is proud to be part of this partnership, contributing with our unique ultra-low-power technology platform for managing energy harvesting and full control of wireless electronic systems.

In the following, we will briefly discuss two of the key areas within ENLIGHTENED - energy harvesting and flexible electronic circuits - and how their combination can stimulate the emergence of a brand new class of better, more sustainable electronics.

Energy harvesting

We live immersed in ambient energy. Such energy exists in multiple forms and is essentially free: yes, it’s here for grabs! So, why are all our small electronic gadgets built around batteries instead of tapping into all this free energy? 

Truth be told, from a glance, batteries are relatively cheap and in many ways convenient. But if we stop a little to think about a product’s whole lifecycle, we stumble upon low battery (inevitably at the least convenient occasions!), multiple battery changes, drawers full of used batteries leaking nasty metals that most certainly end up in landfills… And, all of a sudden, costs start piling up and convenience slips away.

But is there any better way? Back to that whole free ambient energy! With a little ingenuity, it is possible to craft devices to harvest energy from sunlight or artificial lighting, radio frequency waves, motion or thermal gradients, and use such energy to power electronics. The good news is that talented scientists and engineers have already crafted many such neat energy harvesting devices. The amounts of energy obtained aren’t huge, but, if used wisely, are more than enough to keep small electronic gadgets, like the ones typically powered by coin cells or alkaline batteries, up and running. This is where a combination of optimised energy harvesting devices and ultra-efficient power electronics becomes handy!

Here, we are not going to enter into details about other forms of energy harvesting, but rather focus on the one starring in ENLIGHTED: light, and in particular low-intensity light, like typically found in indoor environments.

There are diverse PV technologies that can be used to harvest light and, in particular, a number of emerging technologies focused on efficiently harvesting indoor light, such as dye sensitised solar cells (DSSC), perovskite-based or organic photovoltaic (OPV) cells. In a previous article, we provided an overview of key concepts, technologies and market players. The ENLIGHTENED project focuses on OPV technology provided by the project leader, Epishine. Epishine’s OPV modules are already best-in-class, providing high-efficiency, flexibility, seamless integration and low cost. Notably, OPV technology shows the lowest environmental impacts among competing alternatives. A large part of the project is dedicated to improving OPV technology (materials, design, integration and production) with a view towards mass-scale real-world applications within IoT and small electronics.

Flexible printed electronics

Electronic boards, so-called printed circuit boards or simply PCBs, are the backbone of any mainstream electronic device. Despite obvious improvements that span across the whole electronics industry, the foundational aspects of PCBs have remained stable over several decades. This means that the backbone of present day electronics is still very much rigid PCBs, based on subtractive production techniques using etched copper and stiff fiber glass composite substrate, commonly known as FR4. These can be produced in a cheap way in high-throughput automated industrial lines. However, traditional PCBs are bound to some serious limitations.

First, the rigidity of FR4 means limited design flexibility: form factor and design of devices must be done around a stiff PCB board, and make room for one or more batteries (plus a battery hatch for changes). This is obviously very limiting when you think of wearables, smart clothing, biomedical sensors and the like. But also across other product categories like sensors, trackers or smart labels to be deployed, for instance, in industrial IoT or the automotive sector - where new form factors, size, thinness and flexibility can be game changers.

Second, PCB production typically accounts for as much as 35% of the total environmental footprint of an IoT device, due to energy-intensive subtractive processes that use many chemicals and generate waste. Hence, if we want to make electronics more sustainable, then this must be one of the pressure points.

The approach in the ENLIGHTENED project is to move into flexible or hybrid (rigid-flex) electronics, where circuits are printed on flexible polymeric substrates, such as PET, using conductive inks based on copper or silver. Hence, we move away from subtractive production processes, which are inherently wasteful, into more sustainable additive/printed techniques, while enabling thinner, lighter and flexible electronic system backbones. This will free developers for new form factors and new product typologies. The ENLIGHTENED consortium includes two companies specialised in printed electronics, Tracxon and Flexoo, which are driving the development of new flex-board designs and respective manufacturing processes based on ink printing and SMD (surface mount device) component assembly.

A flexible power module made for sustainable IoT products

Part of the ENLIGHTENED consortium has been focused on developing a flex-board module for powering IoT devices. Energy is harvested by Epishine’s OPV cells and stored in small SMD or pouch supercapacitors or rechargeable batteries. ONiO.zero provides system control and advanced energy management. The consortium has been testing different electronic designs, substrates and conductive inks to optimise the module. This module is intended as a power unit adaptable to diverse IoT or small electronic devices. The module can be connected to application-specific flex-boards or conventional PCBs for end product deployment. The size of the PV cell and of the energy storage element can be tuned to serve the requirements of different use cases.

In conclusion, batteries and conventional PCBs have been solid contributors to the boom of wireless electronics and IoT devices. Yet, this legacy is proving restrictive as the industry explores new avenues in terms of design and product typologies, while facing increased pressure for sustainable alternatives. The ENLIGHTENED project intends to unchain developers from the legacy of batteries and rigid PCBs. The course is set: self-powered, flexible and sustainable electronics made possible!