Disposable alkaline batteries have quite an impressive shelf life. They can last for years without being used. But once you start using them, it is only a matter of time before they die. The same goes for every other type of battery. From NiCads to lithium-ion batteries, they all die at some point. Understanding why reveals one of the hidden truths behind energy storage.
If someone were to ask you whether or not a battery stores electricity, how would you respond? Most people would say ‘yes’. It is just something we’ve been led to believe in the absence of a better explanation. But guess what? It’s not true. Batteries do not store electricity; they store energy in the form of ions.
You could have a solar thermal system that provides heat and hot water to your home. That system could have a salt-based battery to store excess energy for use once the sun goes down. Yet that battery would not store electricity. It would store energy.
How Batteries Work
If all of this is confusing, you are not alone. But no worries, Pale Blue Earth, a Utah company that sells a revolutionary USB rechargeable battery, makes it clear by explaining how batteries work. According to the Pale Blue Earth team, a battery housing contains a few chemicals along with protons and electrons.
In the case of lithium-ion batteries, the chemical mixture within contains lithium. There are ions in that lithium. Charging a battery requires using electricity to push those ions from the positive side of the battery to the negative side. A fully charged battery has all of the ions located at the negative side – but no electricity.
Discharging works in the opposite direction. When the ions inside move through the chemical field back toward the positive side, a chemical reaction takes place. That reaction produces both heat and electricity. Electricity flows from the positive side of the battery into the device being powered.
Normal Battery Discharge
Most of a battery’s discharge is realized by powering some sort of device. The more ions move to the positive side of the battery, the more discharge occurs. A fully discharged battery would have all of its ions on the positive side.
There are three things to know in this regard. First, it’s rare for modern lithium-ion batteries to be fully discharged. Internal circuitry prevents that because it reduces battery life. Second, the process of moving ions from one side to the other gradually breaks down the chemical components inside.
Third, batteries can self-discharge over time. Even when not in use, ions naturally flow from the negative side to positive. The rate of discharge varies from one battery to the next. Different battery technologies also discharge at different rates.
Finally, we can conclude that batteries eventually die because the chemicals inside break down. Simply put, they wear out. They gradually decay with each reaction until ions moving through them no longer initiate the necessary reaction. And where there is no reaction, no electricity is generated.
There is no such thing as a battery that will never die. Everything in the natural world is subject to breakdown and decay. That includes the energy-producing materials inside a battery. As a side note, forget the myth that putting your batteries in the freezer will extend their lives. Any small extension you might realize will be insignificantly small.
Now you know why batteries eventually die. You also know that they do not store electricity. Pass the information on to your friends. They will be surprised by just how much you know about batteries.