How Thin Film Batteries are Changing Device Design

Thin film batteries have brought significant changes to the device design process due to their uniquely thin shape. It seems like a simple conclusion: thinner batteries enable thinner devices.

The connection between device design and the volume taken up by the device’s power source is more complicated than simply yielding more volume for the device’s function. Approaching the design process while accounting for thin film batteries gives the designer more options in terms of the device’s size, shape, and even flexibility.


Historically, electronics have been very bulky for various reasons including durability, scalability, and the size of eletronic components. Another major reason, however, is the space taken up by the power source. In the past 15 years or so, the trend has been towards electronic devices that are thinner than those developed earlier because the components can be much smaller now. In many cases, devices can now fit in the user’s pocket, in their hand, or around their wrist. Decreasing thickness further to even thinner dimensions requires a thin film battery.

With technological developments that allow for a device’s power source to decrease dramatically in thickness, the power source can more effectively match the size of the technology that provides the device’s function. Thin film batteries can serve this purpose for many different devices; their utility for a multitude of modern technologies is well documented. Already, they power everything from medical technology to wearable devices.

A few examples that fit both of these categories are patient monitoring systems, emergency notification devices, and new drug delivery patches. Devices that are in the medical field and are wearables benefit from being thin because each can be worn directly on the body. For patient comfort, these devices should be as thin as reasonably possible, while maintaining their function, and thin film batteries enable all of these of the devices.

Traditional batteries cannot fit the requirements of these devices because they need the thickness and flexibility of a thin film form factor. A stack of thin film batteries can offer comparable function while adding more options in terms of versatility. They can fit in more specific areas within the device while still increasing the voltage.

The benefits that the thin film form factor provide have to be considered in contrast to the alternative for low space cost battery form factors, specifically coin cell batteries. They are readily available, inexpensive, small but rigid batteries that are commonly used in many small devices. While coin cells are a better design for some devices; the future of small devices will rely on the thin film form factor.

In addition to the technological trend of reducing device size, flexible electronics have been under commercial development for decades. The technology of flexible circuits, however, has not been able to realize its full potential due to the lack of a flexible battery to match it. More recent developments in flexible batteries have opened up a new set of options of potential devices. Even without flexible batteries to match them, flexible circuits have been used for in-vehicle electronics for cars and trucks and cell phones’ battery packs and screens.

Combining flexible circuitry with a flexible power source would allow a much greater range of possibilities, as a rigid power source has limited these options in the past. Combining flexible circuits with thin film batteries is an idea that people have already tried to capitalize on; there are several patents for this concept, including uses such as card reading for credit cards and temperature control for spacecraft.

The Internet of Things has brought a demand for thin and concealable battery power for small devices. Bluetooth low energy technology enables low power devices to add the feature of connectivity with electronic devices. An example that is present in the market is the disposable wireless thermometer, which transmits the temperature data to a location separate from the patch so the patient can be monitored easily.

Placing a coin cell, which has a thick, round, prism-shaped form factor, in devices that require precise use of space in order to maintain an acceptably small size is more difficult than finding room in the device for a flat plane. Additionally, if the device must be flexible, the coin cell presents the problem of having a portion of the device that is not flexible.

After assessing the direction that different types of devices are headed in, there will be a greater demand for electronic devices and products that have traditionally required no power to add small and convenient batteries. The thin film form factor aligns itself perfectly with the opportunities presented by the rise of the Internet of Things, and it will continue to push the boundaries of electronics as long as developers continue to seek smaller options for their power sources.


About the Author


Hi, I'm John, editor-in-chief of an Flexel Battery online magazine!

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