Simplergy#11 What a titanium and finnish ring taught me about microbatteries?
How a chance encounter with biohackers led me down a rabbit hole of microbatteries, wearable tech, and the art of miniaturized engineering
A few months ago, I started noticing something peculiar.
In meetups and conversations with biohackers (people deeply invested in optimizing their health) I kept spotting the same accessory: a shiny, metallic ring made from titanium. Sleek, minimal, and almost futuristic, this wasn’t just a fashion statement.
It was the Oura Ring.
Curious, I asked a few of them how it had changed their lives. Here’s what I heard:
Person #1:
“My sleep has improved drastically. I now know exactly when I’m reactive and when I’m calm. The app even shows my pulse graph it’s wild to see stress play out in real-time.”
Person #2:
“I love that it tracks everything from my steps to my breathing even while I sleep. It’s like wearing a lab on my finger. I can literally feel my body better now.”
That was my lightbulb moment.
We’ve entered a new era of wearables - devices that empower without distracting.
What powers these tiny devices?
Coming from a background in designing large-scale energy storage systems for commercial and industrial use, I was fascinated by the challenge of powering something this small. How do you fit sensing, computing, wireless communication, and power all into something the size of a wedding ring?
That curiosity led me into the world of microbatteries.
What Are Microbatteries?
Microbatteries are miniature energy storage devices designed for compact electronics where traditional batteries just won’t fit. They’re a key enabler of ultra-small devices like wearables, smart rings, implantables, and AR glasses.
Anatomy of the Oura Ring
The image below described the teardown of the oura ring with its critical components
Oura ring uses 3.7V, 21mAh battery that provides upto 8 days of power
source : https://www.ifixit.com/Teardown/Oura+Ring+2+Teardown/135207
After watching teardown video of the Oura Ring, I was blown away by its architecture. It’s a masterclass in compact engineering:
Biosensors: Infrared PPG for heart rate, NTC for temperature, accelerometer & gyroscope for movement and respiration
Power System: A tiny lithium-polymer battery (15–22 mAh depending on size), managed by a battery management system (BMS)
Wireless: Bluetooth Low Energy for syncing data
Microcontroller: A Nordic chip processes everything locally before syncing with the app
Shell: Durable titanium, water-resistant up to 100m
Designing Batteries for Consumer Wearables
It got me thinking: how would one even begin to design a battery for something like this?
Key factors to consider:
Form Factor: Thin-film or coin cell depending on space
Safety: Especially important for skin-contact or implantable devices
Weight: Needs to be light enough not to affect comfort
Chemistry: Lithium-polymer, solid-state, or zinc-air depending on use case
Rechargeability: Tradeoff between longevity and replaceability
Integration Complexity: Must fit tightly with sensors, PCBs, and housing
Size Constraints: Millimeter-scale is the new norm
Types of Microbatteries
Final Thoughts
From massive grid-scale batteries to micro-scale storage inside a ring, I’ve realized that energy systems are scaling in both directions. And the tiniest ones might just have the biggest impact on our health, daily habits, and even how we relate to our own bodies.
The Oura ring is just beginning of hacking the human body, as with the advancement in compute, chip innovation and human-interaction device, there’ll be major breakthrough in the hardware - software integrated devices in the coming decade promises a wave of breakthrough battery powered innovations
If you’re curious about the future of energy follow along. There’s a lot more to uncover in the layers of this beautifully complex world of new energy landscape!