How to maximise battery life in wearable medical devices

Optimising power consumption is essential for expanding the wearable medical device market further. How can designers and manufacturers achieve this optimisation? Zac Amos, Features Editor at ReHack, further explores.

The necessity of improving wearable battery life

Medical wearables become more compact and lightweight yearly. Despite their diminishing size, users expect them to have more features and last longer between charges. Otherwise, these devices may not appeal to them. According to one recent survey, 23% of workers in the United Kingdom cite battery life as a barrier to adoption.

Compact batteries have a higher internal resistance than their larger counterparts, meaning they tend to have worse discharge capabilities, like a larger voltage drop between terminals. The consequences – accelerated component degradation and elevated energy loss – significantly shorten a device’s life span, lowering its perceived value.

Concurrently, wearables are becoming more power-hungry. Components like advanced sensors and edge artificial intelligence are resource-intensive. Power consumption optimisation is critical if industry professionals want the market to take advantage of the latest technology trends.

While many consider wearable medical devices necessary, most patients are wary of digitised testing and monitoring. Approximately 78% of people prefer in-person visits, highlighting the importance of making modern technologies more appealing. Industry professionals must maximise power savings and reduce energy loss for the market to expand.

How to maximise battery life in medical wearables

Several strategies exist for maximising discharge efficiency, battery capacity and storage life.

1. Strategic battery selection

Currently, lithium-ion batteries are largely considered standard. However, far more efficient alternatives exist. For example, a zinc-silver battery can maintain 91.45% capacity after 1,000 cycles and 72.9% capacity after 2,400 cycles. Other notable bonuses are its high discharge efficiency, long dry storage life and minimal self-discharge rate.

2. Low-power standby mode 

Wearable medical devices collect and transmit information in short bursts. Their batteries tend to degrade faster when they remain on while inactive. Inactivity is of particular concern during warehousing and shipping, where devices remain inactive for weeks or months at a time. A low-power mode suppresses current leakage, maximising available power during startup.

3. Recycled batteries 

Sometimes, recycled batteries are more efficient than their newly manufactured counterparts. For instance, a lithium nickel manganese cobalt oxide battery can maintain 70% capacity at 11,600 cycles, which is 53% better than a new commercial alternative. Moreover, its rate performance is 88.5% better than that of commercial powders. 

4. Low-power techniques  

Engineers should consider novel low-power techniques during the design phase. While standard strategies like signal compression are advantageous, power-hungry components and increasingly compact batteries necessitate advanced measures. Since data transmission is the most resource-intensive activity, power gating and compressive sensing are vital.

Considerations for reimagining battery design

Industry professionals tweaking device design to accommodate power management changes must consider how consumers will react. While disposable wearables are a cost-effective choice, reusability is a value-adding factor influencing people’s perception of their purchase’s worth.

Consumers view this technology as a non-necessity. According to one recent survey, although 52% of British people have owned a wearable device, just 35% actively use one – around 17% no longer own or use one.

If consumer buy-in stagnates, so will the market. Although experts predict venture capital investments in the wearable medical device market will increase by approximately 14% by 2027, positive growth is not guaranteed. Industry professionals must prioritise convenience, aesthetics and comfort when optimising power management.

The future of medical wearable batteries

A combination of low-power techniques, strategic battery selection and self-discharge prevention modes will help research and development teams build medical wearables that last longer and perform better. However, industry professionals should consider building on these measures to uncover novel optimisation methods to guide the future of component design.