Stanford researchers develop a new durable battery that can be pulled and stretched as TAFFY
Stanford researchers develop a new and durable battery that can be pulled and stretched like TAFFY without any reduction in power or efficiency
- Stanford Engineering scientists have developed a new elastic battery
- The battery can be thrown twice its resting length without power reduction
- The team believes it could be used in a wide range of portable health devices
Stanford Engineering researchers have developed a new flexible battery housed in plastic that can be stretched and folded in the same way as human bodies do.
The team believes that the new device could be useful in the growing market for portable computing devices such as exercise trackers and smart watches, providing a light energy source that can be adapted to a wide range of sizes and applications.
In conventional lithium-ion batteries, plastic particles, called polymers, are used to drive negative ions to the positive pole of the battery, creating energy for any device to which they are connected.
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Stanford researchers have developed a new and elastic battery (pictured above) that can be extracted twice its original length without interrupting its power supply
In lithium-ion batteries, these polymers take the form of gels housed in a rigid housing, a system that has proven flammable in the past.
Stanford’s team says its new battery has turned these polymers into a solid and elastic substance instead of a gel, which makes its battery more flexible and less flammable.
It is important to note that the capacity of the battery to deliver energy does not change depending on the way it is pulled or pressed.
The team extended the battery to twice its original length and did not find the corresponding energy loss.
“So far we have not had a source of energy that can stretch and bend the way our bodies do it, so we can design electronic devices that people can comfortably use,” chemical engineer Zhenan Bao saying Stanford Engineering Magazine.
The prototype version of the battery is about the size of a miniature and stores about half the energy of a conventional battery of the same size.
The researchers hope to continue developing the technology to be able to store even more ounces of energy per ounce and believe it could also be used with BodyNet, a flexible family of portable computing devices that is also being developed at Stanford.
BodyNet is an ambitious project that seeks to develop a full body skin sensor array to collect a wide range of biometric data.
The researchers say the battery is less flammable than traditional lithium-ion batteries, which use a polymer gel to transport negative ions to a positive pole, because the gel may leak
The battery is being developed with another Stanford research project in mind called BodyNet (pictured above), the network of portable sensors means adhering to a person’s skin and collecting a wide range of biometric data.
Last year, researchers showed a BodyNet prototype with metallic ink as an antenna embedded in an elastic tag that would adhere to a person’s skin and measure their pulse, body temperature, stress levels and a variety of other health indicators.
Stanford chemical engineering professor Zhenan Bao, who helped develop the technology, says it could eventually be used to help control patients struggling with a variety of health conditions, including sleep disorders and heart conditions.
“We believe that one day it will be possible to create a matrix of full-body skin sensors to collect physiological data without interfering with a person’s normal behavior,” Bao said.
HOW DOES PORTABLE TECHNOLOGY WORK?
Physical activity trackers such as Fitbits or smart watches monitor heart rate using a technique called photoplethysmography.
The tracker sends green light through the skin that is partially absorbed by the arteries.
As you exercise, these arteries expand as blood flow increases, which means that more green light is absorbed rather than reflected in the tracker.
The tracker calculates your heart rate by seeing how much light is reflected.
The amount of light that passes through the skin to the tracker can be affected by the amount of melanin in the skin and any tattoo.
One of the main measurement tools of portable sleep monitors is called actigraphy, which has been used in medical sleep tests for decades.
The actigraphy records the movement through a measuring device called an accelerometer.
The idea is that a certain amount of movement will be recorded as ‘awake’ and the periods of being still correspond to being ‘asleep’.
Sleep trackers with a heart rate tracking function can measure their variations in heart rate to assess sleep quality and other parameters.
Trackers that measure the body’s core temperature use this information to predict stress levels and fertility, for example.