Lithium-Ion Batteries: The Powerhouse of Electric Vehicles (PART I)

Lithium-ion batteries (LIBs) are the most popular energy storage device for powering electric vehicles (EVs) due to their high energy efficiency, lack of memory effect, long cycle life, high energy density, and high-power density. They are not only the potential for cleaner transportation but also result in broad shifts in geopolitical power, industrial dominance, and environmental protection.

Composition of Lithium-Ion Batteries

The cells in a lithium-ion battery are composed of several key minerals that are the science behind the phenomenal power source. Some minerals make up intricate parts within the cell to ensure the flow of electrical current, while others protect it from accidental damage.

The mineral content is based on the ‘average 2020 battery’, which refers to the weighted average of battery chemistries on the market in 2023. The cells in the average battery with a 60 kilowatt-hour (kWh) capacity contained roughly 185 kilograms of minerals.

Here is the breakdown of the mineral composition of an average 2020 battery.

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 Lithium-Ion Batteries

Lithium-ion batteries are superior due to their cost efficiency and energy storage capacity. Lithium is very reactive, and batteries made with it can hold high voltage and exceptional charge, making for an efficient, dense form of energy storage.

These batteries are expected to remain dominant in EVs for the foreseeable future thanks to costs and improvements in performance. They typically weigh around 454 kg, cost around R250 000 to manufacture and have enough power to run a typical home for a few days.

Each battery is a densely packed collection of hundreds, even thousands, of slightly mushy lithium-ion electrochemical cells, usually shaped like cylinders or pouches. Each cell consists of a positive cathode (which typically contains metal oxides made from nickel, manganese, and cobalt); a negative, graphite-¬based anode; and a liquid solution in the middle, called an electrolyte.

Lithium Iron Phosphate (LFP) batteries, a type of lithium-ion battery, have emerged as a favoured choice for car manufacturers in the realm of EV battery technology. Their safety enhanced thermal stability, longer lifespan, higher power density, and environmental friendliness have positioned them as a compelling alternative to nickel and cobalt-based chemistries.

Composition of Lithium Iron Phosphate Batteries

The basic structure of an LFP battery consists of four main components:

1. Cathode: Lithium iron phosphate (LiFePO4)
2. Anode: Graphite or other carbon-based materials
3. Electrolyte: Lithium salt dissolved in an organic solvent
4. Cell Container

The cathode is the battery’s positive electrode and impacts its performance. It determines aspects such as energy capacity, charging and discharging speed, and the risk of combustion. In LFP batteries, the cathode composition consists of three elements:

• Phosphate: 61%
• Iron: 35%
• Lithium: 4%

Superiority of Lithium Iron Phosphate Batteries (EV)

LFP batteries offer several compelling advantages:

1. Safety: LFP batteries are among the safest types of lithium-ion batteries, with a low risk of overheating and catching fire. They are less prone to thermal runaway and do not release oxygen if they catch fire, making them safer than other lithium-ion batteries.
2. Long Life Cycle: LFP batteries have a longer lifespan than other types of lithium-ion batteries due to their low degradation rate. They can be charged quickly without significant battery damage, leading to a longer lifespan. LFP batteries can also withstand a larger number of charge and discharge cycles, meaning they can last longer before needing to be replaced.
3. Cost-Effective: The materials used to produce LFP batteries are relatively cheap compared to other types of lithium-ion batteries. The main cathode materials used in LFP batteries are iron and phosphate, which are in relative abundance in contrast to other battery metals. This makes them a cost-effective option for a variety of energy storage applications.
4. Environmentally Sustainable: LFP batteries are environmentally sustainable because they are non-toxic and do not contain harmful heavy metals such as cobalt or nickel. The materials used in these batteries are easier to source ethically, which makes them a more sustainable option than other types of lithium-ion batteries.
5. High Voltage and Power Density: LFP batteries offer high voltage, power density, and a long life cycle. They generate less heat and offer increased safety.
6. Thermal Stability: LFP batteries are much more thermally stable, reducing the risk of battery fires.

Lithium-Ion Batteries: The Powerhouse of Electric Vehicles (Part II)

Lithium-Ion Batteries

Lithium-ion batteries are superior for several reasons:

1. High Energy Density: Lithium-ion batteries offer a higher energy density than other designs. This means they can store more energy in the same amount of space, making them an ideal choice for applications that require lightweight, compact energy storage, such as electric vehicles.
2. 2. No Memory Effect: Unlike some other types of rechargeable batteries, lithium-ion batteries do not have a memory effect. This means they do not need to be fully discharged before recharging, and partial discharge/recharge cycles do not cause the battery to ‘remember’ a lower capacity.
3. Low Maintenance: Lithium-ion batteries are comparatively low maintenance. They do not require scheduled cycling to maintain their battery life.
4. Versatility: The design of lithium-ion cells allows for customising the size and shape to suit specific needs. This makes them adaptable to different types of electric vehicles.
5. Scalability: These cells can be scaled up to meet the demands of large electric vehicles.
6. Long Cycle Life: Lithium-ion batteries have a long cycle life. This means they can go through many charge and discharge cycles before their capacity starts to degrade.
7. Fast Recharge Times: Lithium-ion batteries can be recharged quickly, making them more convenient for use in electric vehicles.

Comparison with Other Battery Types

When compared to other types of batteries, lithium-ion batteries stand out in several ways:

1. Nickel-Manganese-Cobalt (NMC) Batteries: NMC batteries have high energy density and allow for longer ranges in EVs. However, high nickel content can make the battery unstable.
2. Nickel-Cobalt-Aluminum (NCA) Batteries: NCA batteries share nickel-based advantages with NMC, including high energy density and specific power. However, NCA cathodes are relatively less safe than other Li-ion technologies, more expensive, and typically only used in high-performance EV models.

In conclusion, lithium-ion batteries offer a combination of high energy density, long cycle life, and fast recharge times that make them an ideal choice for electric vehicles. Their versatility and scalability also allow them to be used in a wide range of applications, from small electric cars to large commercial vehicles. The lithium-ion battery has revolutionised the electric vehicle industry by providing a reliable, efficient, and cost-effective solution for energy storage. As technology continues to advance, we can expect further improvements in the performance and cost-effectiveness of these batteries, paving the way for a more sustainable future.