Apple recently announced support for health features in its wearable devices that could impact billions of people. The Apple Watch now offers sleep apnea notifications, while AirPods Pro 2 provide the world’s first all-in-one hearing health experience with a clinical-grade, over-the-counter hearing aid.[1] A crucial component common to both of these wearable devices is the battery. These devices must function for extended periods, even when the wearer is asleep or in noisy environments, to provide the user experience and benefits needed.
This week’s New Tech Tuesday examines solid-state lithium micro-batteries and the impact they will have on the wearable market.
Solid-state lithium micro-battery technology is making significant advancements, particularly in applications for wearables, hearables, and small IoT devices. Unlike traditional lithium-ion batteries that use liquid or gel electrolytes, solid-state micro-batteries use a solid electrolyte, enhancing both safety and energy density. These batteries will offer longer lifespans and quicker charging times and are more resistant to thermal issues than conventional lithium-ion counterparts, making them suitable for compact, high-performance applications.
While solid-state lithium micro-batteries are promising, their commercial availability is still developing. Their small form factor, coupled with their durability and energy performance, is expected to support next-gen wearables once companies resolve manufacturing and cost challenges hindering broader adoption.
Nevertheless, several major companies are actively developing wearable devices with solid-state micro-batteries. Samsung, for instance, has been exploring solid-state battery technology for its Galaxy wearable lineup, including the Galaxy Watch and Galaxy Ring.[2], [3] Other companies, like TDK, are also making strides in solid-state battery solutions for wearables (Figure 1), with the potential to increase battery life up to 100 times compared to current technologies.[4]
Figure 1: This single cell of a solid-state battery was developed as a material for the next generation of CeraCharge™. (Source: TDK Corporation)
Solid-state micro-batteries have several advantages over traditional lithium iron phosphate (LFP) batteries. They can store more energy in a smaller volume, leading to more compact and powerful batteries for devices we regularly wear or have connected around the house. They can also reduce downtime by charging faster, while the solid electrolytes help minimize the risk of leakage, overheating, and thermal runaway, improving overall safety. Additionally, solid electrolytes reduce the battery’s degradation over time. Lastly, the nature of solid-state materials enables thinner and more adaptable batteries, facilitating greater innovation in wearable and flexible electronics.
When paired with the right devices, solid-state micro-batteries play a pivotal role in powering the future of wearables and other small sensing products. Mouser Electronics offers a comprehensive inventory of next-generation products from Vishay and TDK InvenSense that significantly enhance the performance of modern, compact devices and emerging wearable applications.
The Vishay VEMD8082 silicon PIN photodiode is a high-performance photodiode for wearable devices, especially in health monitoring. Its sensitivity to visible and near-infrared light makes it ideal for accurate biometric measurements like heart rate and SpO₂, while its slim profile allows for integration into tight spaces. The low dark current minimizes noise when no light is detected, and its rapid response time enables real-time monitoring. Additionally, its low power consumption extends battery life, making it suited for continuous monitoring tasks.
The TDK InvenSense EV_ICM-45605 evaluation board is a comprehensive development platform for the ICM-45605, a high-performance six-axis MEMS motion tracking sensor that integrates a three-axis accelerometer and a three-axis gyroscope. The platform is centered around a Microchip Technology, the SAMG55 MCU, facilitating rapid evaluation and development of sensor-based applications that include hearables, wearables, virtual reality (VR), and augmented reality (AR) glasses, among other cutting-edge applications.
Solid-state micro-batteries are still in an early stage of development, but they have the potential to provide performance and safety advantages that make them well-suited for modern, compact devices, especially next-generation wearable applications.
Sources
[1] https://www.apple.com/newsroom/2024/09/apple-introduces-groundbreaking-health-features/ [2] https://www.techradar.com/health-fitness/samsung-galaxy-watch-could-get-a-massive-battery-life-boost-thanks-to-solid-state-technology [3] https://www.prnewswire.com/news-releases/all-solid-state-battery-for-wearables-unveiled-by-semco-samsung-electro-mechanics-302265197.html [4] https://www.tdk.com/en/news_center/press/20240617_01.html
Rudy Ramos brings 35+ years of expertise in advanced electromechanical systems, robotics, pneumatics, vacuum systems, high voltage, semiconductor manufacturing, military hardware, and project management. Rudy has authored technical articles appearing in engineering websites and holds a BS in Technical Management and an MBA with a concentration in Project Management. Prior to Mouser, Rudy worked for National Semiconductor and Texas Instruments..