What Are Lithium Batteries?

Lithium batteries offer high energy and power density pound for pound, inch for inch. You’ll find them in virtually all portable consumer electronics and cordless tools, plus plug-in hybrids and electric cars.

A lithium battery uses a chemical reaction to store energy in its anode and cathode. During charging, lithium ions move from the positive current collector through the separator and meet up with their long-lost electrons on the negative side of the cell.

Types

There are several different types of lithium batteries. Each type is designed for a specific use and has unique advantages. For example, Lithium Iron Phosphate (LiFePO4) batteries offer high power density and long cycle life, which makes them an ideal choice for electric vehicles and solar energy storage. Lithium Manganese Oxide (LiMnO2) batteries are a good option for cordless power tools and hybrid and electric vehicles because they provide a balance between energy density and safety.

Lithium batteries are made up of anodes and cathodes that store electrical charge in the form of lithium ions. An insulating material separates the anode and the cathode to prevent short circuiting. The electrolyte is a non-aqueous solution of an organic solvent that contains lithium salts. Lithium batteries can be found in many different electronics, including cell phones, laptop computers, and cordless power tools. They also can be used for backup power for home and business applications.

There are several different types of lithium batteries, but it is important to select a battery with an intelligent Battery Management System (BMS) that optimizes the characteristics of the selected chemistry. A BMS can also ensure equal performance over time and the safe operation of the battery in any application.

Applications

Lithium batteries have a wide range of applications thanks to their high energy density, rechargeability and lithium battery long lifespan. They are used in electric vehicles, power tools, portable medical devices (pacemakers and hearing aids) and renewable energy storage systems to store energy from solar panels or wind turbines for use when new energy isn’t available.

A lithium battery’s specifications depend on its cathode and anode materials and its electrolyte. The positive electrode is made of a non-flammable metal such as aluminium or nickel. The negative electrode is usually made of graphite or a composite material. Both electrodes allow lithium ions to move in and out of their structures with a process called intercalation or deintercalation. This chemistry is well understood and is the basis of lithium-ion cell design.

During charging, the electric current lowers the chemical potential of the cell by removing lithium ions from the anode to the electrolyte. This process releases chemical energy as heat and transfers it through the external circuit.

A lithium battery can be damaged by improper charging or handling. When this occurs, it can short circuit or even catch fire. This is why all Li-ion cells are supplied with a safety cell management system to control critical operation parameters. Another risk is the formation of dendrites in an anode. These grow thicker over time and deplete the cyclable lithium inventory of a cell. They also increase the cell impedance, reducing cycling capacity and stability.

Safety

Lithium batteries supply power to many kinds of devices lithium battery from cell phones and laptops to scooters, smoke alarms and toys. But, in rare cases, lithium battery packs can overheat, catch fire or explode. This is usually due to a manufacturing problem or physical abuse.

The most common problems involve the electrodes, separator and electrolyte. The cathode and anode contribute to energy storage and release; the separator physically divides the electrodes to prevent internal short circuits; and the electrolyte carries ions, including Li+. The malfunction of any of these parts can negatively impact the battery’s safety [36].

Overheating is a major cause. The internal temperature of a lithium battery pack can rise to 130degC (265degF) or more. This can cause the cells to become thermally unstable, and the resulting fire can spread to neighboring cells in a chain reaction, releasing flaming gases into the air. The high temperatures of these fires can last for hours, and they can burn combustible materials like plastic and clothing.

Fortunately, most lithium battery packs are designed with several safety features to mitigate these hazards. These include a built-in PTC device that protects against overvoltage; a circuit interrupt device (CID) that opens the electrical path if an excessively high charge voltage raises the internal cell pressure to 10 Bar (150 psi); and a safety vent that allows a controlled release of gas when the cell temperature reaches 90degC (194degF).

Recycling

A lithium battery contains a significant amount of high-grade materials such as cobalt, iron and nickel. It’s important to recycle these batteries at their end of life. In fact, the Department of Energy estimates that battery recycling could grow 10-fold over the next decade.

However, traditional industrial battery recycling methods are inefficient and prone to environmental harm. For example, they usually involve mechanically shredding and smelting the battery’s components to strip them down to elemental metals. That involves using a lot of energy and creating secondary pollution such as sulfide and oxide emissions.

Yan Wang, a materials science professor at Worcester Polytechnic Institute who co-authored the new study, has been working on a more effective and environmentally benign approach to battery recycling. His method, which he calls direct recycling, avoids the need to separate the different battery parts into elemental metals. Instead, he uses low-energy plasma to refresh the cathode powder’s active material and directly regenerate it into a new battery.

In addition, it eliminates the need for other battery processing steps like smelting or dissolving, which consume a lot of energy and generate waste products such as sulfide fumes and acid. In the future, the process might reduce the need for mining metals from mineral ores and also cut carbon dioxide emissions. In the meantime, you can recycle your battery by contacting its manufacturer, the retailer where it was purchased or your state’s household hazardous waste program for direction on how to properly dispose of it.