A guide to different types of batteries in 2021 - What is all the Lithium-ion battery talk about

The vast consumption of fossil fuels and natural energy resources made it imperative to introduce a source of energy that was both sustainable and renewable. Other than solar, hydro, and wind energy, it led to many inventions that can help us live a little better and a little greener. One of those inventions is an electric vehicle or an EV. Naturally, they would take electricity from charging stations, which will, in turn, go into energy-storing devices, called "Battery". This little tit-bit of information is important because while the motor is responsible to get the wheels of your vehicle turning, these rechargeable batteries are responsible for power up the motor. 

Simply put, if the EV was a human body, the motor would be the brain that keeps you going, but the battery would be the heart and soul responsible to keep you alive. One of the most important factors that you need to consider when thinking about the battery for an EV is the battery capacity, which is expressed in terms of the kilowatt-hours or the kWh. The higher the number, the better returns it will give. All-electric cars have battery capacities between 6.0 kWh to 100kWh on average. 

It becomes very important to know what types of batteries are available to you, and how each of them contributes to your EV. Let’s get started: 

Lead Acid Batteries (1859)

Composition:

A lead-acid battery consists of a negative electrode made of spongy or porous lead. The lead is porous that allows the formation and dissolution of lead. The positive electrode consists of lead oxide. Both electrodes are immersed in an electrolytic solution of sulfuric acid and water. If the electrodes come into contact with each other through movement of the battery or through changes in the thickness of the electrodes, an electrically insulating, but chemically permeable membrane separates the two electrodes. This also ensures safety because the membrane also prevents electrical shorting through the electrolyte.

History

Lead Acid Batteries are of the cheapest and the most common battery vehicles available, especially for automobiles. They are known for their high value of load current. Invented in 1859 by Gaston Plante, it is a concentrated mixture of water and acid and is as much as 85% effective. Before Lithium-ion batteries were introduced, lead-acid batteries were what kept the world of electronics going (some of them still do). 150 years later, we still have no cost-effective alternatives for cars, wheelchairs, scooters, golf carts and UPS systems.

Advantages & Disadvantages

Some of the biggest advantages of these batteries are:

• Low in cost
• High specific power
• Capable of high discharge currents

But unfortunately, the disadvantages of Lead-acid batteries out-weight their advantages. This is also one of the reasons why newer batteries were introduced in the market, to reduce the following disadvantages:

• Low specific energy 
• Poor weight-to-energy ratio
• Slow charging 
• Corrosion, water-loss & internal short 
• Adverse environmental impact 

 Over the years, Lead-Acid batteries underwent many evolutions, such as follows:

1. Sealed Lead Acid: A misnomer term, because no acid battery can be fully sealed, these batteries have the ability to combine oxygen and hydrogen to prevent drying or heating. Sealed batteries also have a higher charging capacity and are extremely low maintenance. 
2. Starter Batteries: A Starter battery, as the name suggests, is designed to shock the engine with a sudden burst of momentary high-power load that lasts only for a second or two, giving it a jump-start. These batteries have low internal resistance, which is probably why they do not offer deep-cycling or continuous power. 
3. Deep-Cycle Batteries: These batteries are designed to provide continuous power. They are built for maximum capacity and a very high load capacity. 

It should be noted that most of the Lead-Acid batteries are used in the automobile industry for cars, trucks, bikes, etc, but rarely in the world of Electric Vehicles. 

Nickel-Based Batteries (1899s)

History

Limited in availability because of environmental restrictions, this battery type is limited in terms of its application and accessibility. Invented in 1899 by Waldemar Jungner, Nickel-Based Batteries are robust and super high-performing. It is expected that they will make up more than 10% of the vehicle industry by the year 2025, but are expected to work together with Lithium-ion because of its cost.

Advantages & Disadvantages

They offer the following advantages:

• Long shelf-life
• High power density 

But again, the downsides are manifold:

• High self-discharge 
• Poor efficiency with time
• Poor performance in cold weathers 

To combat all of these disadvantages of Lead and nickel batteries, Lithium-ion Batteries emerged into the picture.

Lithium-ion Batteries (1960s)

History

The first, and perhaps the most common type of battery is the Lithium-ion battery. Introduced in the 1960s by Jean Rouxel and Robert Schroeder, Lithium-ion batteries have had no looking back since. Most widely used in cell phones and laptops, Lithium-ions are the leading battery type for electric vehicles because of their high density and its minimal self-discharge when not in use. They also come in solid-state.

Composition:

Li-ion batteries consist of largely four main components: cathode, anode, electrolyte, and separator.

“Cathode” determines the capacity and voltage of a Li-ion battery. A Lithium-ion battery generates electricity through chemical reactions of lithium. This is why, of course, lithium is inserted into the battery and that space for lithium is called “cathode”.

”Anode” sends electrons through a wire. Just like the cathode, the anode substrate is also coated with active material. The anode’s active material performs the role of enabling electric current to flow through the external circuit while allowing reversible absorption/emission of lithium ions released from the cathode.

“Electrolyte” allows the movement of ions. It serves as the medium that enables the movement of only lithium ions between the cathode and anode.

”Separator”, the absolute barrier between cathode and anode. The separator functions as a physical barrier keeping the cathode and anode apart. It prevents the direct flow of electrons and carefully lets only the ions pass through the internal microscopic hole.

Advantages & Disadvantages

Lithium-ion batteries have many advantages as compared to nickel and lead-acid batteries, including:

• Low-maintenance
• Low self-discharge rate
• High energy density
• High cell-voltage
• Ready to go cells (no priming needed) 
• Variety of types to choose from

The invention of lithium-ion batteries is welcome progress in favour of the electric vehicle revolution in the world. Advanced research is being done to innovate technologies that optimize the functioning of lithium-ion batteries to their optimum efficacy so that is more cost-effective and fit for mass application.

Electric Vehicles have begun to use variations of the Lithium-ion battery as they continue to be experimented on in the labs. They can further be categorized into the following types: 

1. Lithium Cobalt Oxide (LiCoO2) — LCO: This battery is often used in digital devices. It has the ability to deliver high-current in hot or cold temperatures but is losing demand because of its relatively low life span and limited load capabilities. 
2. Lithium Manganese Oxide (LiMn2O4) — LMO: These batteries have an improved internal architecture which leads to decreased resistance and high thermal stability. However, they rely on cobalt, nickel, manganese, and/or aluminium for better results.
3. Lithium Nickel Manganese Cobalt Oxide (LiNiMnCoO2) — NMC: One of the most successful combinations, NMCs are also tailored to serve as energy cells or power cells. NMC is the go-to combination for EVs, with one of the only drawbacks being that Cobalt is both expensive and limited in supply. 
4. Lithium Iron Phosphate (LiFePO4) — LFP: LFP offers good performance with low resistance, and extremely tolerant as compared to the other lithium-ions. But because of its low energy capacity and flat voltage discharge, it is mainly used for energy storage. 
5. Lithium Nickel Cobalt Aluminium Oxide (LiNiCoAlO2) — NCA: Used by companies like Tesla and Panasonic, NCA offers high specific energy and a long life span. Needless to say, it offers great stability and high power stability. If you have NCA in your EVs, you have very little to worry about.
6. Lithium Titanate (Li2TiO3) — LTO: LTO charges fast and can maintain itself even in low temperatures. Thermal stability under high temperature is also better than other Li-ion systems. It is one of the safest batteries to use, but the high cost limits its applications. Currently, efforts are being made to lower its cost. 

Every day in the battery industry is taking us closer to a new breakthrough that can change the way we work. Ideas are being drawn for the lithium-ion battery by adopting to use it through single crystal cathode material. Gaining longer life and holding higher capacity is driven by the electric vehicle industry that is striving for 15-year battery life! And this is just the tip of the iceberg. 

With the advancement of technologies, batteries have become smarter enabling intelligent battery management system. Today lithium batteries are tech aided to the extent that the charging, heating, and over-heating of the cells are closely monitored and communicated to the user with built-in display in EV vehicles. No price for guessing then, Electric Vehicles equipped with smart lithium-ion batteries are going to bring in the future as much as in the blink of an eye. Until then, I hope that this article has helped you scratch the surface of what a battery means in the world of Electric Vehicles, and how you can navigate through it. 

Just Getting Started

Rahul Thakur