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Batteries are the beating heart of tomorrow’s medical devices

Medical device technology is advancing rapidly. Patients and healthcare professionals alike seeking better quality of life and more convenient and efficient health management are driving demand for innovation. These next generation devices can now be enabled by rapidly improving low-power electronics, better sensors, more efficient mechatronics, flexible software, and increasingly ubiquitous communications technologies.

How are medical devices evolving?

The medical device sector is one of the most innovative in the world, second only to the digital communications sector as measured by number of patent applications. In 2021, there were more than 15,300 applications for medical technology patents, according to MedTech Europe’s analysis of the European Patent Office’s Patent Index. The Facts and Figures report also suggests that medical technology products have a short lifecycle of just 18 - 24 months before being upgraded, which further highlights the sector’s innovativeness.

Smartwatches deliver data at your fingertips
Smartwatches now increasingly provide health-monitoring functions, such as pulse-rate and blood oxygen monitoring. Some can even add single-lead ECGs and temperature sensing, with ambitions to eventually measure blood pressure from variations in blood flow.

More convenience with smartphones
Smartphones are just one device that has created a platform for innovation, as well as brought more convenience to health management. For example, ultrasounds can be performed at home rather than in a hospital. A specialist can use a handheld wand for sensing and a mobile phone to display the results. Diabetics are also benefiting from continuous monitoring of their glucose levels, using a discreet sensor applied to the skin and a mobile phone for data analysis and presentation.

There are many other medical-device technologies already available, such as electronic thermometers, hearing aids, pain relief systems, insulin pumps, medical alert systems, and pill dispensers. Over the next five to 10 years, we can expect development of more complex wearable health monitors, smart inhalers that track medication usage, smart pills that sense and report the environment within the body, and more sophisticated telehealth solutions to bring medical diagnostics and health consultations into the home.

How to power medical devices

But, all these innovations need powering. And as medical devices are expected to become more complex, they will demand more onboard signal-processing, machine-learning and general computing power, as well as more sophisticated mechatronic systems.

This means we will need higher-performance batteries to drive them. We also need batteries that have assurances of product traceability, that have been manufactured to high quality standards, and meet the strict safety requirements set by regulators worldwide.

At ÂÜÀòÓ°ÊÓ, we have an enviable history in battery innovation, first developing mercury-free technology for silver-oxide batteries in 2005. We have since continued to develop a range of mercury-free silver-oxide batteries for medical devices. They are designed to deliver the required high performance, including:
- high energy storage density
- the ability to produce short pulses of high currents when needed, for example, to drive mechatronic devices.

The SR927R batterys

Our SR927R silver-oxide battery, which has a nominal voltage of 1.55V and energy storage capacity of 45mAh, has some useful characteristics that medical device designers can harness. It is part of a family of batteries that offer higher energy densities than many other cells in the same form factor. They can also deliver higher currents at times of peak demand and sustain their output voltages at more useful levels for longer than standard parts in an equivalent form factor.

Let’s take a closer look at their performance:

Graph 1 shows that, at a constant current of 50mA, our SR927R battery maintains an output voltage of at least 1V for more of its discharge curve, therefore delivering more energy, in a more useful way than the standard variant can.

Graph 2 also demonstrates this advantage, by showing how the battery’s output voltage changes over time when driving a standard load.

What benefit does this performance have for end users?
The SR972R battery can maintain an output voltage close to the Open Circuit Voltage (OCV) of 1.55V for approximately 240 hours – this would enable a device requiring a 1.55V supply to operate autonomously for at least ten days without user involvement. Therefore, using the SR927R battery to power more advanced electronics that could function at voltages of less than 1.55V would result in even greater end-user convenience.

The SR44R battery

Our SR44R cells also have a 1.55V nominal voltage, but offer an energy storage capacity of 150mAh (three times higher than the SR927R battery). Their maximum discharge current into a standard load of 4.7kΩ is 120mA, which can be maintained for up to 100ms at an output voltage greater than 1.2V. This pulse discharge current is almost three times higher than that sustained by standard SR44 cells!

Graph 4 highlights that the SR44R batteries can also deliver more of the stored energy at useful operating voltages compared to standard parts.

Powering the future

With increasing demand for more advanced healthcare, the necessity for more sophisticated medical devices is rising. These devices will need to include enhanced sensing and analysis capabilities as well as communicate with cloud-based analysis services and healthcare providers. Powering all these functionalities will require batteries that have been specially designed for medical devices, and that's where we can help. For further details visit