Why Trust Techopedia

What Does Battery Mean?

A battery is an energy source consisting of one or more electrochemical cells and terminals on both ends called an anode (-) and a cathode (+). Electrochemical cells transform chemical energy into electrical energy. Inside the battery is an electrolyte, often consisting of soluble salts or acids, it serves as a conductive medium, allowing the electric charge to travel through the battery.


When a battery is disconnected, the charge at the positive and negative ends is equal, meaning there is no electric current. When connected to an outside resistance or device, the battery experiences an imbalance in charge that pushes electrons through the device's conductive material to the positive end of the battery. But while the electrons—or the negative charge—are what moves through the circuit, the electric current is measured following the positive charge's direction, which flows from the positive to the negative end inside the battery, and vice versa outside it.

Depending on its voltage and load, a single battery can power anything from a car's motor or a computer to a cellphone or a light bulb. When it comes to most electronic devices, working with the wrong voltage could result in your device not turning on or risk frying its electrical components, sometimes beyond repair.

The right voltage battery would be able to power a device without hindering its performance or harming its hardware. Also, depending on the device's consumption of energy and the battery's load, a single battery charge could last you anywhere from a few hours to multiple days.

Techopedia Explains Battery

Batteries come in all shapes and sizes to suit various needs. They range from miniature batteries used in wristwatches and hearing aids to several meters wide, serving as an emergency power resource or storing renewable energy from solar power plants and wind farms.

Benjamin Franklin coined the word "battery" to refer to linked capacitors in his experiments, but it was Alexandro Volta who developed the first "real" battery, in 1800. Since then the usefulness and ubiquity of these power cells has increased steadily.

Generally, batteries are classified as either primary or secondary batteries, according to the type of electrochemical cells they are made of.

Primary Batteries

Primary batteries, also known as nonchargeable batteries, are disposable batteries that can only be used once. That is because the chemical reactions that produce electricity in their electrochemical cells cannot be reversed. The materials that react together to produce electrical energy cannot go back to their original, pre-reaction state.

These batteries are often used in portable devices that do not require much energy, such as remote controls and children's toys. Disposable batteries are widely used because they are convenient, cheap, require little to no maintenance and are reliable in an emergency.

But not all disposable batteries are the same. The components of a battery's electrochemical cells play a significant role in its performance and applications. Zinc-carbon batteries are the most common type, thanks to their low cost and reliable performance. In comparison, batteries like alkaline batteries and mercuric-oxide batteries serve a more niche audience. They are more costly than their zinc-carbon counterpart, but are more stable and can function in extreme environments and weather conditions, and have an overall longer shelf-life.

Secondary Batteries

Secondary batteries are rechargeable batteries that can be used more than once but have a set life expectancy. Because of their durability and ability to provide larger amounts of energy, they are often used in larger devices such as laptops, tablets, and even cars. After a rechargeable battery exhausts its electrochemical energy, an external electric current can reverse the chemicals back into their original state, ready to repeat the cycle of electricity production all over again. Like electrical devices, when recharging secondary batteries, the charger needs to provide the right voltage for the battery. Too high of a voltage could drastically shorten the battery's lifespan, cause a fire, or ruin its electrochemical cells.

When it comes to the types of rechargeable batteries, they are divided according to their chemical composition and the state of the electrolyte into wet- and dry-cell batteries. Wet-cell batteries are the oldest type of rechargeable battery. They contain liquid electrolyte with two electrodes submerged into it, acting as the battery's anode and cathode. Wet-cell batteries are often used in demanding industries such as aviation, electric storage, cell phone towers, and electric utilities as they are affordable and durable in the right circumstances.

Dry-cell batteries are not entirely dry, despite the name. Their electrolyte consists of a paste with just enough moisture to allow electrons to travel through. These are the rechargeable type often used in portable electronics like phones and laptops as they are considered to be safer. Lithium-ion (Li-ion or LIB) batteries are the most commonly used type of rechargeable batteries. When optimized, their energy density can increase by 56.8%, giving them the highest power-to-weight ratio, allowing them to be compact while still providing energy efficiently. Recent studies also found that Li-ion batteries can be prevented from deteriorating by administering short, intermittent high-current pulses during its use.

Other types include nickel-metal hybrid (NiMH), nickel-zinc (NiZn), and nickel-cadmium (NiCd) cells. Similar to disposable batteries, they vary in capacity and durability. NiMH batteries are often favored over NiCd because of their higher battery capacity and lack of toxic metals. However, NiCd batteries are still widely used in medical equipment and power tools because of their longer lifespan.


Related Terms

Margaret Rouse

Margaret jest nagradzaną technical writerką, nauczycielką i wykładowczynią. Jest znana z tego, że potrafi w prostych słowach pzybliżyć złożone pojęcia techniczne słuchaczom ze świata biznesu. Od dwudziestu lat jej definicje pojęć z dziedziny IT są publikowane przez Que w encyklopedii terminów technologicznych, a także cytowane w artykułach ukazujących się w New York Times, w magazynie Time, USA Today, ZDNet, a także w magazynach PC i Discovery. Margaret dołączyła do zespołu Techopedii w roku 2011. Margaret lubi pomagać znaleźć wspólny język specjalistom ze świata biznesu i IT. W swojej pracy, jak sama mówi, buduje mosty między tymi dwiema domenami, w ten…