A lithium-ion battery is a type of rechargeable battery that uses compounds containing the metal lithium in its cathode electrode and is charged and discharged by utilizing lithium-ion transfer. Due to its features such as compact size, lightweight, and a long lifespan, it is widely used in various fields, including familiar consumer electronics such as smartphones and laptop computers, as well as electric vehicles and both residential and industrial energy storage systems.

To use lithium-ion batteries safely, it is essential to thoroughly understand their principles and proper usage. In this article, we will explain the characteristics of lithium-ion batteries and how they generate electricity.

What Is a Lithium-Ion Battery

First, let's briefly explain the types of batteries. Batteries can be categorized based on their mechanisms and applications into two main groups: chemical batteries, which generate electricity through chemical reactions, and physical batteries, which convert physical energy--such as heat or light--into electricity. Each of these groups is further divided into more specific categories.

Chemical batteries are classified into three types: primary batteries, which are single-use; secondary batteries, which are rechargeable and can be used repeatedly; and fuel cells, which continuously produce electricity through chemical reactions. Lithium-ion batteries fall under the category of secondary batteries within chemical batteries.

Physical batteries are classified into three types as well: solar cells, which convert sunlight directly into electrical energy; thermoelectric batteries, which generate electricity by using heat energy in high-temperature environments; and nuclear batteries, which produce electricity using energy generated from the decay of radioactive materials.

Lithium-ion batteries use compounds containing the metal lithium in their electrodes, and are charged and discharged by the transfer of ions between the positive and negative electrodes. Since lithium is an extremely light and small element, batteries can be made compact and lightweight even when containing a large number of lithium atoms.

Thanks to their compact size and excellent durability, lithium-ion batteries are used in consumer electronics such as smartphones and laptop computers. In addition, their ability to store large amounts of electricity makes them widely used in electric vehicles and infrastructure systems.

Advantages of Lithium-Ion Batteries

Before lithium-ion batteries became mainstream, lead-acid batteries were widely used for various applications. So why have lithium-ion batteries gained such attention? It's because they offer numerous advantages over the lead-acid batteries that had previously dominated the market.

•  High energy density allows for the production of compact, lightweight batteries with large capacity
•  Rechargeable with excellent fast-charging performance
•  Minimal "memory effect," a phenomenon in which battery capacity decreases when recharged without being fully discharged, leading to a longer lifespan
•  Made from materials with low environmental impact
  

As explained above, the features of lithium-ion batteries are well-suited to the demands of modern electrical and electronic devices, which continue to become smaller and lighter.

While lead-acid batteries are inexpensive, they have drawbacks such as being heavy and bulky, having long charging times, and a shorter lifespan. Because they contain lead and sulfuric acid, there are also concerns about environmental impact and recycling issues. Given their ability to overcome these issues, the market demand for lithium-ion batteries is expected to continue growing.

History of Lithium-Ion Battery Development

The development of lithium-ion batteries--now essential for mobile devices and electric vehicles (EVs)--began in the 1950s.

Progress in technology over the years have made lithium-ion batteries a major benefit to humanity. The achievements of the researchers who received the Nobel Prize laid the foundation for today's technology-driven society.

How Lithium-Ion Batteries Work

Lithium-ion batteries consist of a positive electrode, a negative electrode, a separator between the two electrodes, and an electrolyte.

The positive electrode uses a metal compound containing lithium, while the negative electrode can store lithium. During charging, lithium ions move from the positive electrode to the negative electrode through the electrolyte and are stored there.

When the lithium ions stored in the negative electrode move back to the positive electrode, an electric current is generated.

Characteristics of Lithium-Ion Batteries

Lithium-ion batteries are rechargeable, lightweight, have high energy density, and offer a long lifespan. However, they are relatively expensive and require careful handling to ensure safety.

Let's Use Lithium-Ion Batteries Safety

While lithium-ion batteries offer many advantages, they also carry a risk of ignition due to overcharging or physical damage such as impact from dropping, making proper handling essential.

Figaro provides information on gas sensors that can detect gases internally generated by lithium-ion battery degradation or external stress on batteries, as well as on safety measures that make use of these gas sensors.

For more details, please refer to the Figaro Journal article: "Early Detection of Lithium-Ion Battery Abnormalities! Safety Measures Using Gas Sensors."