What is a Lithium-Ion Battery?

The electric car has been around since the early days of the automobile and was even ahead of gasoline cars at the turn of the 20th century. At that time, 38% of the American car fleet was electric.

What slowed down its progress was the discovery of oil and its large-scale extraction through drilling. Additionally, industry players like Henry Ford focused on mass-producing internal combustion engine vehicles. Another factor was the limitations of old lead-acid batteries, which had a maximum range of around 100 kilometers. It was the introduction of the lithium-ion battery in the mid-1960s that revitalized the popularity of electric cars.

But how does a lithium-ion battery work? What are its advantages and disadvantages, and why has it recently gained so much momentum in the market? Here are some explanations.

The earliest concepts of electric vehicles powered by lithium-ion batteries date back to 1967 when AMC (American Motors Corporation) unveiled an electric concept called the Amitron. This small urban vehicle offered a range of 241 kilometers with a lithium-nickel-fluoride battery that had a capacity of 22.5 kilowatt-hours.

Over the years, automakers and independent companies introduced marginal electric vehicles to the market, sold in small quantities, mainly as technological showcases. Examples include the Jet Electrica 007, a converted Dodge Omni, and the Chrysler TEVan, an electric Caravan. The GM EV1 in the 1990s marked the first serious attempt to lease a viable electric car to the general public.

However, the high cost of lithium supply deterred automakers from pursuing electric vehicles. It was much simpler and cheaper for the industry to prioritize internal combustion engines.

It was the electronics market in the early 2000s that improved lithium’s accessibility. By obtaining smaller quantities of the metal for compact devices, the electronics industry was able to absorb supply costs and create economies of scale, making lithium more accessible and affordable.

Tesla: The First to Use Lithium-Ion

Tesla became the first automaker to use lithium-ion batteries to power a production car with the Roadster in 2008. The Tesla Roadster prototypes, dating back to 2004, used a series of lithium-ion batteries (a total of 69) sourced from laptop computers.

By 2010, battery manufacturers were already responding to this new trend and producing large-format lithium-ion batteries for powering vehicles. This allowed Nissan to launch its first LEAF in 2010, followed by the Mitsubishi i-MiEV in 2011. Today, lithium-ion batteries power nearly all electric vehicles.

How Does a Lithium-Ion Battery Work and What Are Its Applications?

The lithium-ion battery gets its name from the lithium ions that reside and circulate inside the electrolyte, a vital component for the battery’s operation.

As of now, all electric vehicle batteries on the market use a liquid electrolyte. This conductive liquid facilitates the movement of lithium ions carrying electrical charge.

During the recharging process, electricity flows through the cathode. The cathode’s chemical composition reacts to this charge, allowing it to release an electron. This electron then charges a lithium ion floating in the electrolyte like a balloon in the air. The chemical properties of the electrolyte protect the ion and can even introduce additives such as vinylene carbonate, enhancing its conductivity.

When we say a battery is fully charged, it means all the lithium ions inside the electrolyte have been charged with electricity. When the battery is used, these ions come into contact with the anode and transfer their electricity. This energy transfer process forms the basis of a battery’s power capacity.

What is a Solid-State Battery?

It is important to note that the electronics market has already begun using solid-state electrolytes, eliminating the need for a conductive liquid in a battery. This technology is also being considered for automotive applications due to its high energy density and endurance. However, its current high costs are hindering its development.

Knowing all of this, we realize that the amount of lithium inside a battery is not very high. In fact, it accounts for only about 7% of the materials used in its construction. The cathode and anode represent the majority of the metals in a lithium-ion battery.

What is Battery Degradation?

Battery degradation refers to its reduced ability to hold a charge or take longer to reach full charge. It is directly related to the wear and tear on the cathode. Depending on its composition, the cathode becomes less capable of releasing electrons to charge the ions in the electrolyte as it ages. As a result, the battery’s performance decreases.

To address this, battery manufacturers manipulate the chemistry of their batteries to improve their energy density (the ability to produce a certain amount of energy per unit weight), endurance, and reduce costs. This explains the variety of lithium-ion battery models available on the market.

For example, the cathode and anode of an NCA (nickel-cobalt-aluminum) lithium-ion battery are composed of nickel, cobalt, and aluminum, while an NCM (nickel-cobalt-manganese) battery is composed of nickel, cobalt, and manganese.

What are the Advantages and Disadvantages of Lithium-Ion Batteries?

The clear advantage of lithium-ion batteries over old lead-acid or nickel-metal hydride (NiMH) batteries is their ability to store more electricity, deliver it over a longer period, and withstand more charge cycles.

The extensive use of nickel in the cathode has significantly improved efficiency and energy density. Currently, the energy density of lithium-ion batteries ranges from 150 to 325 watt-hours (Wh) per kilogram, with an endurance of 500 to 1,500 charge cycles.

However, nickel is not without its drawbacks. It is expensive, costing around $350 per kilowatt-hour. Its extraction is also environmentally polluting.

To address these issues, some automakers have replaced nickel with iron, resulting in the lithium-iron-phosphate (LFP) battery composition. Although its energy density is lower at 120 watt-hours per kilogram, its costs are significantly lower, around $260 per kilowatt-hour. Additionally, LFP batteries have shown greater endurance than nickel-based lithium-ion batteries, exceeding 2,000 charge cycles.

Lithium-ion batteries with liquid electrolytes remain sensitive to high temperatures, and instabilities within the liquid electrolyte can lead to fires. Therefore, significant investments are being made in solid-state electrolyte technology to enhance the safety of lithium-ion batteries.