We already wear technology, from Apple watches to devices that monitor our vitals for medical
reasons.
There are even researchers in Sweden developing an in-body intranet that can link all wearable
medical devices!
As more and more things become integrated into our bodies, batteries will have to follow.
Right now, batteries are rigid, meaning whatever you put them in -- like a cell phone -- has
to be rigid.
Then there’s that pesky issue where lithium-ion batteries in cellphones have a tendency to
explode when bent or punctured.
We’re going to need a different power solution before we can better integrate personal devices
around our flexible bodies, and we’re already seeing some early flexible battery technologies
in the making.
One recent development isn’t the battery elements but a binding agent for the elements.
But let’s back up for just a second.
All batteries are like little columns or bricks.
The internal elements are: the negatively charged anode, the positively charged cathode,
and some kind of the electrolyte that separates them.
Once the circuit is closed — say when a battery is put in a flashlight — electrons
can travel from the anode to the cathode, powering the light bulb along the way.
So back to this new thing…
A team of researchers have created a new kind of glue that can bind battery elements together
with hydrogels.
Hydrogels are water-based materials that aren’t dissimilar to the tissues that make up human
muscles and flesh.
The battery isn’t stretchy, but the casing is!
The new glue is made of super glue's main ingredient — cyanoacrylate — mixed with
an organic non-solvent that delays the fluid’s hardening.
This allows the adhesive to permeate porous materials before it sets, creating an instantaneous
and strong bond.
It’s an adhesive that can hold 2.2 pounds (1 kilogram) and stretch as much as 2,000
percent.
The glue tech is well suited to stretchable batteries, electronic skin, and even hydrogel-based
patches loaded with sensors.
But it’s not just this new glue that’s getting us closer to stretchy electronics!
A different team from the University of California Berkeley developed a battery that can stretch
and bend.
They took the elements of a battery and arranged them end to end along a helical spring or
flexible wire… basically a tiny slinky that experiences minimal stresses when it’s bent.
This is an ideal form for a bracelet, making these stretchy batteries a great option for
wearables that need to be in contact with the skin.
Another design sees a wire snaking along in a flexible polymer such that when it’s flexed
the wire stretches without decreasing the battery’s chemical power.
These batteries can be charged like any other battery, but the Berkeley team is looking
ahead at incorporating tiny solar cells, because the more devices we have the less practical
it will become to plug each one into the wall to recharge.
So, we have a stretchy case and we have stretchy battery elements, but this is all still in
the lab.
Stretchy batteries are years away, but, like, 5 years away, not decades!
Just think, someday stretchy batteries could let us bend a cell phone around our wrists
before we work out… or maybe bring back slap bracelets -- but way more technologically
awesome ones.
If you’re worried about plugging all these things in though -- maybe don’t?
Wireless charging might be on the way thanks to this new design.
Check it out here.
Let us know what tech you’re excited to have stretchy batteries for in the comments,
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