The architecture of flexible batteries allows them to stretch and conform to various shapes, in contrast to their rigid equivalents. They may be encountered in rechargeable and non-rechargeable forms, and users can even wrap them around items without worrying about their power storage capacity diminishing.

The components

A flexible battery, as opposed to a traditional hard battery, uses lightweight, bendable components. This frequently entails:

• Electrodes: These are constructed from conductive polymers or unique coatings applied to flexible carbon fiber or graphene substrates. Conductive polymers are plastics that allow for the flow of electricity while being bendable. Materials like graphene or metallic nanowires are deposited on flexible substrates like plastic films.

• Electrolytes: Similar to traditional batteries, but with modifications to maintain conductivity when flexed. The medium that allows ions to flow between electrodes is tweaked for flexibility. This can involve replacing liquid electrolytes with solid versions that can tolerate bending, or liquid electrolytes can be held within a flexible polymer matrix.

Where can these batteries be used?

Flexible batteries open doors for innovative applications that traditional batteries can't handle. The need for flexible batteries stems from the rise of new devices:

• Wearable electronics: Smartwatches, fitness trackers and even medical monitors require batteries that can move with our bodies. Rigid batteries can be uncomfortable, especially during exercise. Flexible batteries conform to the wrist, providing a more comfortable wearing experience. Many fitness tracker and smartwatch functions, like step counting, heart rate monitoring and basic notifications, don't require a lot of power. Current flexible batteries can potentially handle these tasks. However, for features requiring significant power, like GPS for long runs, current flexible batteries might struggle.
• Flexible displays: Imagine foldable phones or roll-up TVs — flexible batteries are key to powering these future gadgets as flexible power sources can bend along with the display. However, a foldable phone or roll-up TV with a small, flexible battery might have limited screen-on time. For extended usage, a larger battery could work but that might compromise the portability of the device.
• Medical devices: Imagine implantable medical devices that conform to a patient's body or bandages that deliver medication through built-in flexible batteries. For example, flexible batteries can power skin patches that monitor vital signs or deliver medication through microneedles. Flexible batteries can power tiny sensors that can be swallowed to monitor internal health conditions. Moreover, flexible electrodes paired with flexible batteries could be used for non-invasive brain activity monitoring.
• Integration with everyday objects: Flexible batteries could be embedded in clothing for heating or health monitoring purposes. For applications like maintaining a comfortable body temperature in cool weather, flexible batteries might be suitable. They could provide enough low-level heat. However, if the goal is to use clothing to generate substantial warmth, like for winter sports, most current flexible batteries wouldn't be powerful enough. They simply wouldn't be able to deliver the voltage and current needed for sustained high heat.
• Smarter clothes: Clothing embedded with flexible batteries could power health sensors or even light-up displays. Compared to heating elements, light-up displays typically use less power, especially if optimized with low-power LEDs. Therefore, smaller, simpler displays can run for extended periods on a single charge of a flexible battery. Similarly, many health sensors, like those measuring heart rate, temperature or blood oxygen, have relatively low power requirements. This aligns well with the current capabilities of flexible batteries.

How soon can users get them?

Flexible battery technology is a rapidly developing field. While they aren't commonplace yet, research is ongoing, and they are already being used in some niche applications. Limited commercially available options exist, but they're mostly for specific uses. Most electronics stores currently prioritize traditional lithium-ion or other established battery types due to their wider consumer base. As flexible battery technology becomes more mainstream, electronics stores might start carrying them alongside traditional batteries.

Flexible batteries are often being offered by specialized manufacturers. For example, these might be found powering things like RFID tags and smart cards. RFID tags are tiny labels with flexible batteries that are used for tracking inventory or managing access control. Therefore, online retailers are also more likely to cater to businesses.

[Find manufacturers and suppliers of flexible batteries on GlobalSpec]

How long do they last?

Currently, flexible batteries generally don't hold as much charge as traditional batteries. However, research is focused on improving their capacity and lifespan. As technology advances, flexible batteries with higher energy density could become a reality, making them more suitable for powering heated clothing. There might be a future where flexible batteries are combined with other technologies like supercapacitors for short bursts of high power, potentially making them more viable for significant clothing heat generation.

Flexible versus traditional batteries

Compared to traditional batteries, flexible batteries offer unique advantages:

• Conformability: They can bend and twist without breaking, perfect for wearable tech.
• Lightweight: Their flexible build makes them lighter than standard batteries.
• Form factor: They can be designed in various shapes and sizes to fit specific needs.

Conclusion

The increasing popularity of wearable tech and foldable devices is driving the demand for flexible power sources. As research progresses, flexible batteries are becoming more efficient and powerful, making them suitable for a broader range of applications. As research progresses, flexible batteries are becoming more efficient and powerful, making them suitable for a broader range of applications.