For more than a hundred years, scientists have been working on building ever better batteries. The big push right now is to improve battery technology enough that we can fully dispense with internal combustion engines. Meanwhile, scientists are also working on batteries to power advanced wearable devices. One team at UC San Diego has even figured out how to use the human body as a battery.
The research team previously made headlines by developing temporary tattoos that transform perspiration into electricity. Now they have a small wearable device that converts fingertip sweat into electricity. Best of all, you don’t have to do any work to generate power. Just stick the device to your finger, like a plastic bandage, and go about your day.
A Constant Source of Sweat
UC San Diego researchers say their new device works based on the knowledge that the fingers are a constant source of sweat. Even if you don’t feel wetness on your fingertips, they are still producing perspiration nearly every minute of the night and day. They produce perspiration even when you’re sitting still doing nothing, and even while you are sleeping.
How does the device turn sweat into electricity? It actually doesn’t. It utilizes some of the chemicals found in human sweat to facilitate a chemical reaction. That reaction is what generates the electricity. In essence, the UC San Diego wearable is similar in function to a lithium-ion battery’s chemical electrolyte.
How Batteries Work
Park City, Utah’s Pale Blue Earth says that the new wearable device perfectly illustrates how batteries work in a rather tangible way. For the record, Pale Blue Earth has developed a revolutionary USB rechargeable battery that can be charged 1,000+ times.
Their batteries work on the same principle as every other battery. Inside is a concoction of chemicals that includes lithium. To charge a battery, you connect it to a source of electricity. Electricity flows through the positive end of the battery, pushing lithium ions through an electrolyte and to the negative end. Discharging the battery reverses the process. As the ions flow through the electrolyte, they facilitate a chemical reaction that produces electricity.
What most people do not know is that batteries don’t store electricity. They store potential energy in the chemicals inside their cases. In a lithium-ion battery, the potential energy is in the lithium. Other types of batteries use different chemical concoctions. The one thing they all have in common is the chemical reaction that creates electricity during discharge.
The Body as a Battery
Getting back to the UC San Diego research, it is logical that the body could be used as a battery given that it produces so many different chemicals. But that’s not even the half of it. Think about this: your body is an endless source of chemicals that could be used to generate electricity. You don’t have to be plugged into a wall outlet to be recharged every day. You just live your life.
Let’s say the UC San Diego device can be scaled up enough to power your cell phone, for example. Say goodbye to plugging your phone into a charger every night. You just put a wearable on the tip of your finger and leave it at that. The mere act of picking up your phone and turning it on would transfer electricity from your wearable device to the phone battery.
It is going to be a long time before that’s possible. But in theory, it should work. By harnessing chemicals our bodies naturally produce, we can literally generate electricity on demand. It is pretty amazing. Take that, Energizer Bunny!