Batteries

Electricity is produced when the ends of a battery are connected by a conducting wire, triggering chemical reactions that release the energy stored in chemical bonds.

A dispute about the origin of twitching frog legs led to the invention of the first battery

Experiments by Luigi Galvani on exposed frog leg nerves showed activity when they were hung from iron railings and brass hooks, suggesting the existence of "animal electricity" that discharged when connected to metals. Alessandro Volta's voltaic pile, which stacked metals with an inorganic electrolyte, showed that electricity originates from chemical reactions.

The first lithium-ion battery was invented at ExxonMobil

Initially a side project that became a priority due to the 1973 oil crisis, the battery's flammability risks and manufacturing challenges, along with the waning crisis, led the company to shut down its battery program. Other researchers would gradually improve upon published prototype designs in the next decade.

Visualize the minerals used in a lithium-ion battery

The lithium cathode includes nickel to increase energy storage per unit volume, as well as cobalt and manganese as stabilizing agents. Anodes are composed entirely of graphite, with aluminum and copper composing the current collectors for the cathode and anode, respectively. The battery is enclosed in a steel casing.

Gradual chemical build-up reduces the effectiveness of rechargeable batteries

During charge cycles, small chemical deposits gradually form a film on the electrodes where they make contact with the electrolyte, trapping ions that would otherwise facilitate the flow of electricity. Mechanical degradation from electrode wear and electrical shorting from structural instability can also reduce battery capacity.

Battery life can be extended by avoiding heat and performing partial charges

Charging regularly in smaller amounts while keeping a battery between 30% and 80% helps maintain lower voltage levels, preventing long-term damage. Some devices continue to draw power when at 100%, which can cause tiny charge cycles and generate heat that degrades a battery's capacity.

Sony set the standard for cylinder-shaped batteries when it repurposed manufacturing equipment used to make rolls of magnetic recording tape.

Batteries range in size based on their purpose, cost, and manufacturability

Lead-acid batteries used in combustion vehicles are resilient to temperature extremes, low-cost, and provide high surge current, which is needed for initial ignition. Alkaline batteries, including AA, AAA, and B, have long shelf lives and supply the low, steady power required for electronics with minimal demand fluctuations.

Watch a tour of a battery manufacturing gigafactory

Inside Contemporary Amperex Technology Limited's facility, China's largest EV battery manufacturer uses slurry mixing, "jelly rolling," electrolyte injection, and other techniques and equipment to transform raw metals such as lithium and magnesium into approximately 2.2 million electrochemical cells daily.

Explore options for recycling batteries

Improper battery disposal can lead to fires and the leaching of harmful chemicals and toxic materials into local soil and water systems. Although many batteries contain metals that can be recycled with less energy than it takes to produce them, variability in regulations across municipalities and states can complicate efforts. (Some readers may experience a paywall.)