Substantiated choice of energy harvesting and storage methods for different use cases: A wide range of hardware modules and techniques exist for energy harvesting and storage. Different energy harvesting methods have different efficiencies depending on the environment and context. Energy storage methods differ in terms of temperature range, charging speed, (self-)discharging rate, cost, form-factor and weight. IoBaLeT will evaluate and compare the combination of different harvesting and storage techniques for various use cases, as well as consider hybrid energy harvesting methods. The resulting lessons learnt can be applied as guidelines to integrate the most suitable energy-related components into IoT devices depending on the use case.
Sustainable environmentally friendly IoT devices: Batteries contain a wide range of dangerous chemicals. As the scale and extent of the battery powered IoT grows, so will its impact on our environment. Depleted batteries are discarded, impacting soil and water pollution and endangering people and wildlife alike. Moreover, malfunctioning batteries can leak or explode, posing a danger during operations to those around them. This is especially impactful for devices that operate in close vicinity of people and animals (e.g., wearables, in-body sensors, wildlife tracking). The battery-less vision of IoBaLeT will address these concerns, resulting in a more environmentally friendly and sustainable long-term IoT applications.
Maintenance-free deploy-and-forget devices: Batteries require frequent maintenance. Non-rechargeable batteries must be replaced as soon as they deplete. Depending on the use case this may be after weeks, months, or at best, a few years. But even rechargeable batteries slowly lose their capacity every time they are recharged, requiring replacement after several years as well. Capacitors have a much longer lifetime and are significantly less sensitive to extreme temperatures. An off-the-shelf capacitor can easily achieve a lifetime of 20 years at temperatures up to 50°C degrees, compared to about 500 recharge cycles at the same temperature for a rechargeable battery. As such, IoBaLeT will support a 20+ year device lifetime at a significantly reduced maintenance cost.
Massive-scale IoT deployments: The use of batteries, and the expensive maintenance they bring, are also a limiting factor in the scale at which IoT networks can be deployed. Current “large-scale” deployments are generally limited to at most a few dozens of devices. Among others, this is due to the high operational costs associated with maintenance. By removing batteries and reducing device maintenance, we expect a significant drop in capital and operational costs. This will result in the potential for truly massive-scale IoT deployments. Existing techniques for extremely energy-efficient communications, such as SWIPT, have only been demonstrated at a small scale. Within IoBaLeT, we aim to significantly improve the scalability of such techniques, to make them applicable to such massive-scale deployments.
Reliable and lossless bidirectional communication using battery-less devices: When changing a stable power supply based on batteries with unpredictable energy harvesting processes and small capacitors, the reliability of the device and applications will suffer. However, SWIPT, as well as hybrid energy harvesting, which combines different harvesting sources to obtain a more stable power supply is expected to significantly reduce the reliability gap between battery-powered and battery-less devices. Within IoBaLeT, we will study and further hone these techniques. Through cross-layer energy-awareness, the application and network protocols can more responsibly utilize the device’s limited energy reserves, leading to further increased predictability and reliability in performance.
Integrated hard- and software co-design: A challenge in product development lies in the uncertainties in the design process itself. Communication, hardware and code all affect factors such as optimal code distribution, feasibility, reliability and accuracy. For efficient development in such a complex design space, it needs to be narrowed down early in the process. Within IoBaLeT, we will define an integrated design flow based on industry standards such as the V-model. From a hardware and software co-design perspective, it will be supported by quantifying energy consumption of hardware, software and communication. This allows early assessment of constraints, requirements and trade-offs, facilitating the design of future battery-less hardware and software technology.