Fit-To-Purpose Batteries. An Ecodesign-Based Approach to Power Portable Applications

Batteries have become an essential power source, due to their capability to deliver high energy densities in a portable manner. However, a close look into conventional portable battery life cycles reveals, that they still follow an obsolete linear model. They are manufactured at specific locations causing scarce material exhaustion, transported thousands of kilometres for its use and then disposed of, sometimes before even its complete depletion. Then, during portable batteries' end-of-life, only a small percentage are recycled, typically using energy intense processes, whereas the rest ends up incinerated or in landfills, generating greenhouse gas emissions and poisoning terrestrial and marine ecosystems. Furthermore, it is forecasted that the upcoming wave of power-hungry Internet-of-Things (IoT) sensing nodes will increase exponentially the portable battery demand in the near future. Thus, aggravating the environmental impact associated with electronic devices production and the generation of waste electrical and electronic equipment (WEEE). For portable batteries to stop contributing to environmental damage, and become an example for sustainable technological development, it is crucial to change the way the batteries value chain is approached.<br/>This work presents a rationale for ecodesign portable batteries by re-thinking their life-cycle under an environmentally conscious framework. Through careful device design and advocating for a ‘fit-to-purpose’ approach, the development of these batteries is paired with the application value chain, in such a manner that even the power source end-of-life is redefined according to the use-case scenario. In order to ground these ideas, several examples of these ecodesigned portable power sources will be presented.<br/>First, a paper-based battery in a lateral flow assay format intended to power portable diagnostic devices. These liquid activated batteries can be fabricated under the same procedures used in the rapid test industry and have shown the ability to power the most relevant features needed in portable medical devices, such as sensors, displays, wireless communications or heating.<br/>Secondly, a bio-based battery using laser induced graphene current collectors in a cardboard tape format for smart packaging. These batteries have the capability to power typical applications envisioned by the sector, such as digital displays and wireless trackers. As validated by normalized evaluation methods, these batteries are complaint with current paper and cardboard recycling processes.<br/>Finally, different approaches of biodegradable batteries for precision agriculture will be presented. These batteries made with organic materials can power sensing devices that measure parameters in soil and the environment and then send the data by Bluetooth communication. The capability to undergo biodegradation has been assessed experimentally using normalized tests as a way to minimize energy consumption at the end-of-life.<br/>Developed under this rationale, environmental sustainability has been placed as a core priority to guide the batteries' conception and materialization, from materials to end-of-life. Hence all materials used as electrodes, electrolytes, or structural components are abundant, non-toxic and renewable; selected to meet the specific end-of-life requirements and endow a safe and ethical manufacturability.