How A Battery Works

To understand how a battery functions, you'll need to first understand the basics of atoms and electricity. An atom consists of three components: proton, neutron, and electrons. Every atom shares the same desire to seek neutrality and stay that way. Every atom is unique in terms of component properties. As a result, they also have different preferences in bonding with other atoms—just like humans.

Some atoms want to shed their electrons; some want to gain electrons, while others want to stay neutral. When a certain atom bonds with another atom, it releases a free electron, which will travel freely along the surface of the conductor to find atoms that'll accept the electron. Those freely moving electrons are what we call electricity.

Components of a Battery

A battery is a device to create, maintain, and control the freely-moving electrons. There are three main components in a battery: anode, cathode, and electrolyte. The anode is a negatively charged metal with many excess electrons, ready to be released to achieve neutrality. The cathode is a positively charged metal that wants to collect free electrons to achieve neutrality.

The electrolyte has a lot of atoms with excess electrons and electron-starved atoms. Every atom and electron from the three components is stable in this state, but they're eyeing one another, itching to move. When one connects the cathode and anode to an electrical load and the circuit is closed, allowing the electrical current to flow.

The anode grabs free electrons from the electrolyte, but they also send electrons moving towards the electrical load. The cathode receives electrons after it went to the electrical load, but it also sends electrons to the electrolyte. Some atoms in the electrolyte capture free electrons released by the cathode, achieving neutrality and forming a different molecule. The cycle continues until all atoms in the electrolyte are neutral.

Real-World Example of a Battery

Odds are, you're probably reading this article using battery-powered electronics. Laptops, smartphones, and tablets are devices that heavily use batteries. Batteries are small enough to fit in those devices' form factors yet can still deliver 2-6 hours of battery life.

Renewable energy-based generators such as wind turbines and solar cells grew significantly over the past years. However, renewables have one massive disadvantage: inconsistency. Solar cells only generate electricity when sunny outside; to counteract this problem, an enormous battery grid is needed to store excess electricity to cover the renewables' downtime. The battery grid can also assist in lifting the electrical load during peak hours.

There is a big push towards electric cars due to the global climate change crisis. Gas-powered vehicles emit CO2 pollutants that heats the earth, while electric cars don't produce any pollutants. Electric cars use massive battery packs to power the electric motors driving the car. For example, the Tesla Model 3 uses hundreds of 18650-type lithium-ion batteries arranged in a specific configuration to achieve the 100kWh (kilo-Watt-hours) capacity and 380DC volts output.

History of the Battery

The earliest battery created dates back to the Late Roman era, 225AD to be exact. Archeologists discovered the Baghdad battery in Ctesiphon city (modern-day Baghdad, Iraq), the Parthian Empire's capital. The battery consists of a ceramic pot containing vinegar or grape juice with an iron bar sheathed in copper inserted in the pot's middle and resembles modern-day batteries with iron as the anode, copper as cathode, and vinegar or grape juice as electrolyte.

However, experts suggested that the Baghdad battery's creation is an accident rather than an entirely intentional invention. The Baghdad battery can only produce a minuscule electrical current, which is completely useless unless someone makes thousands of them connected in series and parallel. Furthermore, while the pot's insides resemble a battery, there's no exposed metal on the outside acting as a terminal to connect electricity.

Alessandro Volta invented the first battery in 1800 by stacking copper and zinc plates separated by saltwater-soaked paper disks. John Frederic Daniel perfected the design in 1836 by using a copper pot filled with sulfuric acid and a zinc tube in the center. The copper pot acts as the cathode, the sulfuric acid acts as an electrolyte, and the zinc tube acts as the anode.

Types of a Battery

The first practical battery invented by John Frederic Daniel used a liquid as the electrolyte. As a result, it's prone to leakage, which is exceedingly dangerous because the electrolyte is highly acidic. It's also impractical to carry around as the liquid may spill out of the battery. This type of battery is called the wet cell battery.

A German scientist named Carl Gassner developed the dry cell in 1886. This type of battery uses an electrolyte in paste form with enough moisture to allow electricity to flow. As a result, the dry cell battery is exceptionally portable. The dry cell battery continues to dominate the market even until now.

In the fourth quarter of 2020, Quantumscape Corp revealed the solid-state battery, a new type of battery that will deliver massive improvements compared to the existing lithium-ion battery. The real magic happens in the electrolyte. Quantumscape created a unique flexible solid ceramic electrolyte that prevents the forming of "dendrites" due to an imperfect lithium-ion diffusion in the anode. As a result, the solid-state battery has more energy density, a faster charging rate, and a broader operating temperature.