Patent published on June 12, 2014

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Samsung and Penn State University are working on a new kind of battery that can charge itself with the movement of your body. The new kind of battery comprises of Graphene based electrodes that can generate electricity directly from external forces.

The importance of battery life cannot be stated enough. With a ton (metaphorically) of gadgets that every household owns, battery life can become quite a concern if it’s not good enough.

This is what led to the demise of smartwatch industry as a whole. These wearable gadgets are still considered a luxury accessory and their battery life is what pull people off the deal most of the time. Nobody wants another gadget that requires charging every other day.

In an attempt to solve the problem, researchers have tried several things like – using e-ink displays to reduce power consumption, making watches wirelessly chargeable to reduce the hassle of cables, and even utilizing body heat to power the watch.

All of these methods have their downside, e-ink displays have slow response time and they reduce user experience. Wireless charging still requires you to take the watch off. And the watch that runs on your body heat, as developed by the Matrix, offers limited functionality.

You might have heard of Piezoelectric sensors too, that can generate electricity from movements and external forces. Researchers also proposed to use these sensors to power small wearable gadgets so that they can be powered by basic movements of body.

So far, this was one of the best methods that could have helped in improving the battery life of these gadgets, but the only problem was finding an efficient way to harvest that energy. The piezoelectric sensors have relatively low energy output and when reduced in size, their efficiency becomes unfeasible to be used for powering a gadget.

Here’s the problem in Samsung’s and Penn State’s researchers’ own words.

An increase in the use of portable electronic devices has recently increased demand for a power source that may extend an operation lifespan of a battery or replace the battery. Energy harvesting from a mechanical source, such as movement of a human, has especially been on the spotlight as one of the methods that may meet this demand. In recent years, methods based on piezoelectric, electromagnetic, or ionic and variable electrostatic capacitance have been intensely studied as energy harvesting methods. Also, various studies on a flexible material or a ceramic material to be used as a material of a device for energy harvesting have been conducted.

However, low energy and power output due to low electrical and mechanical energy density of a material being used in an energy harvesting device has limited commercialization of a technology using the energy harvesting device, and thus studies from a perspective of various structures and materials to overcome the limitation have been conducted. Thus there remains a need for an improved energy harvesting device.

These limitations led researchers of Samsung and Penn State University to collaborate and develop an entire energy harvesting device or say an alternate to traditional batteries that utilizes Graphene and carbon nanotubes to do the job.

According to a recent patent filed jointly by both of the organizations, the device has a similar structure as of a normal battery, but, instead of using traditional electrodes, they have opted for using nanoporous electrodes made from 30% to 95% of carbonaceous materials (Graphene, carbon nanotubes, and aerogel).

Nanoporous electrodes have a surface area 10x to 100x bigger than that of a traditional electrode, thus giving it more area to harvest and store the generated electricity.

The electrodes are enclosed between electroactive polymers that generate electricity when an external force is applied; quite similar to piezoelectric generators except these polymers are not bigger than just few nanometres.

Here’s the cross sectional diagram of the device proposed in patent –

cell images

The patent also shows that these energy harvesting devices can also be stacked in series to form a bigger battery thus, increasing the overall power capacity.

Even though it’s not mentioned in the patent but, I think these devices will be embedded in smartwatch straps as straps are quite flexible and can easily bend/move.

Battery in smartwatch straps can be a game changer even if it is not new. This concept was earlier revealed at Computex 2014 as covered by Gizmodo. Now Samsung and Penn State University have found an actual way to make this method practical rather than just a theory.

Besides, Samsung shows its intention to unlock a smartphone with using its smartwatch that detects your biometric signals, such as heartbeats.

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