Lithium Ion Batteries
Lithium-ion batteries are used in powering almost all the electronic gadgets around us, from our earbuds to laptops and mobile phones. Their usage is not limited to consumer electronics alone and these batteries are popular in electric vehicle industry as well. Since these are considered to be the most suitable energy storage devices for powering the electric vehicles, the demand for lithium ion batteries has been increasing tremendously in the last few years.
Today, various battery manufacturers and government organizations are undertaking research in making such batteries even more adaptable to electric vehicle industry.
Origination and Fundamentals of Lithium-Ion Batteries
A lithium-ion battery is a family of rechargeable battery types in which lithium ions move from the negative electrode to the positive electrode during discharge and back when charging.
Before Lithium-ion batteries became popular in 1990s, Lead Acid batteries were developed and used in 1800s. Then, Nickel-Cadmium and Nickel-Metal Hydride batteries came and got accepted due to their better performance.
However, there was still a need for a battery that could be easily recharged in a timely manner. In 1991, after a prolonged research around the world by different scientists, Li-ion batteries were finally invented. These batteries became popular within no time and now they are widely accepted in the market.
A lithium ion battery comprises one or more power generating blocks called cells. A battery has following main components: cathode (positive electrode), anode (negative electrode), electrolyte, separator, positive terminal (positive current collector) and negative terminal (negative current collector).
Anode and cathode store the lithium and the electrolyte carries positively charged lithium ions from the anode to the cathode and vice versa through the separator. The movement of the lithium ions creates free electrons in the anode which creates a charge at the positive terminal. The electrical current then flows from the current collector through a device being powered to the negative terminal. The separator blocks the flow of electrons inside the battery.
While the battery is discharging and providing an electric current, the anode releases lithium ions to the cathode, generating a flow of electrons from one side to the other. When plugging in the device, the opposite happens: Lithium ions are released by the cathode and received by the anode.
Factors responsible for popularity of Lithium-Ion batteries
Lithium-ion batteries initially got popular in consumer electronics industry because of their rechargeable quality. Today, they have become a standard for any device that needs a portable rechargeable battery. With their high energy density feature, they are revolutionizing the EV ecosystem as well.
Lithium ion-batteries can work under different conditions that include very low as well as very high temperature, high as well as low drain, and for shock and vibration tolerant environments.
Benefits of Lithium-Ion Batteries
Lithium-ion offers several benefits that make such batteries attractive in various devices.
1) High Power Density
First, Lithium-ion batteries are capable of packing huge amounts of power. They have one of the highest energy densities among different battery types, in the range of 100 – 200 Watt-hour / kg. For this reason, they function as high-power sources for renewable applications, such as electric vehicles
The following diagram (source: University of Washington) depicts specific energy density and volumetric energy density of various battery types -
2) Low self-discharge rates
Self-discharge decreases the shelf life of batteries. For any device that requires a constant source of energy, it is critical to have batteries that have low self-discharge rates, which is a measure of how quickly a cell will lose its energy while sitting on the shelf due to unwanted chemical actions within the cell.
Self-discharge rates vary with different battery types and temperature conditions. Lithium-ion batteries have self-discharge rates in the range of 1% to 3% per month. In comparison, other batteries such as Nickel-cadmium batteries have self-discharge rates in the range of 15% to 30% per month.
3) Low environmental impact and high recyclability
Lithium is non-toxic and completely recyclable. Once these batteries are used, it is easily returnable to the concerned industries where metal salts of lithium, cobalt, nickel and manganese are extracted. These extracted salts are reused in manufacturing various energy storage systems.
Lithium-ion batteries provide clean source of energy and easy to recycle. In comparison, lead acid and Nickel-Cadmium batteries are highly toxic and difficult to recycle.
4) Fast charging
Lithium-ion takes a maximum of one hour or less to charge. This is much faster as compared to lead acid batteries which takes more than 10 hours to charge. Even Ni-MH batteries take two to four hours for charging. With Lithium-ion battery, machines have lesser idle time. This is particularly important in the case of rental cabs and taxis where less downtime leads to more income for drivers.
5) Low maintenance
Lithium–ion batteries require relatively low maintenance as compared to other batteries to keep them operational. These batteries require no extra care to prolong their life as these are not associated with any memory effect.
The slow self-discharge rate in lithium-ion batteries allows a longer life span. For this reason, the average lifespan of a lithium-ion battery is more than eight years. This life span can be further extended with good maintenance and servicing. Lithium-on batteries give good performance for high-power applications and they have the capacity to deliver more current compared to other battery alternatives.
For all these reasons, the lithium-ion batteries have wide range of applications, including consumer electronics, industry applications, military, aerospace and grid energy. However, in the last decade, with increasing popularity of electrical vehicles, Lithium-ion batteries have become perfect alternative, given their high energy density and longer life span.
Lithium-ion batteries shaping the future of electrical vehicle industry
Lithium ion batteries have established themselves as an essential part of electric vehicles, given how these provide the best balance between the performance, cost, weight and size parameters. Today, the electric vehicles, especially the two wheelers, three wheelers and cars, are the biggest demand generator for lithium-ion batteries. According to a research by ResearchAndMarkets.com, the global lithium-ion battery market size is projected to grow from USD 41.1 billion in 2021 to USD 116.6 billion by 2030. Bloomberg NEF forecasts that demand for electric vehicles using lithium-ion battery technology will grow more than 10 fold between 2018 and 2030. The biggest contributor to this demand for lithium-ion battery is the increasing adoption of electric vehicles in the automotive industry.
With continuous research in this space, the price of lithium-ion technology is coming down. Also, more efficient batteries are getting developed that are allowing vehicles to have higher range. To improve battery features such as longevity and density, alternative materials are getting identified for cathodes. Cobalt or nickel based material are most popular and useful alternatives for cathode in electrical vehicles today.
Usage of lithium-based solid-state batteries is another area that is deeply researched by various public and private agencies nowadays. In such batteries, liquid electrolytes are replaced by solid-state electrolytes that provide a higher energy density and longer lifespan alternative. These are also safer than liquid electrolyte based batteries. However, the cost of solid-state batteries is a barrier to their adoption and more innovation is needed to adopt these fully for electrical vehicles.
As electric vehicles keep becoming the way of life for millions of consumers globally, the innovation in lithium-ion batteries will continue. This will keep pushing the boundaries, bringing newer, smaller and cheaper batteries and yet longer life and more power.