G. Johnson, B.E. Hayden, C.E. Lee, D. Laughman, R. Noble, L. Turner, O. Clarke, P. Casey
Keywords: solid state batteries, thin film, IoT
Summary:Applying its heritage of patented materials invention, Ilika has developed thin-film, solid-state, Li-ion batteries to meet the specific demands of applications in the IoT space. As IoT devices become utilized across a wider range of applications, the ability to fit low maintenance, long life devices by removing the need for cabling or changing batteries regularly becomes essential. Such autonomous sensing devices need to transmit data whilst being self-sufficient for power and requiring no external wired power source. Creating perpetual beacons using energy harvesting technologies such as vibration, thermal, solar to power the beacon typically requires energy storage as a buffer based on the variability of the energy source. This energy buffer, which may be a battery, a super-capacitor or a Li capacitor, has to meet a number of requirements based on the application such as: charge retention; temperature resilience; form factor; lifetime; safety; power requirement (for example to support peak current demanded when transmitting wirelessly over BLE or LORA); sufficient capacity to cope with energy source variability. This ability to be perpetual offers a wide range of opportunities beyond the maintenance benefits. It also enables beacons to be put in difficult to reach places for industrial applications such as down-hole mining; in locations that may not be able to be reached once a building or factory has been built; or in physically remote locations that have no power supply such as found in farming locations. The concept of autonomous sensing device is extendable to applications in agriculture (for the monitoring of light levels, soil content to optimise plant growth, or herd and valuable equipment movement tracking for security purposes), automotive (infotainment, sensors), medical (using in vitro or implantable sensors to improve patient experience by remote monitoring without need to visit place of care). In addition, industry trends in the 5-10 years period show a drive towards miniaturisation of these devices, for example in the area of dust computing for medical implants. Ilika’s advanced electrode and electrolyte materials make them lighter and safer, plus faster to charge and with longer charge retention than lithium ion solutions today. Ilika’s Stereax™ batteries use patented materials and processes, enabling superior energy density per footprint, up to 40% improvement on current solid state solutions and performance to over 100°C, 30°C higher than existing products. The low temperature process allows for the battery to be deposited on the back on the CMOS chip or some other substrate. Ilika is looking to explore the integration of its batteries on chips, for example for the development of millimetre-size devices.