The Hidden Details Behind Lithium-Ion Batteries


A technician ratchets down covers on a battery pack at the Smyrna Vehicle Assembly Plant. Nissan charges forward in electric vehicle leadership with the opening of the largest lithium-ion automotive battery plant in the U.S. on Friday, Nov. 16, 2012.

Lithium-ion batteries are behind almost all of our favorite gadgets and electronics. But how much do we know about them? Let’s get down to the details.

Electric vehicles, smart phones, laptops, even watches. Pretty much all of our portable favorites, which require some sort of power, depend on Lithium-ion (Li-ion) batteries.

Yet, we give very little thought to energy storage, unless it really becomes a nuisance. We happily pack all chargers and power banks, we equip our house with  power outlets and extensions, we take this as part of the deal and we carry on with our daily activities.

Our busy lives have evolved to a state, where delayed gratitude is something from the past. We need to know everything now and if possible yesterday- fast news, fast charge, fast food. This is also why we carry all the chargers and power banks, because we cannot really accept the thought that we will be disconnected from the world- something might happen and we would be the last to know.

But are we right?  Shouldn’t we actually stop for a second and try to understand what is behind this powerful and increasingly more essential invention?

As stated Serena Corr, Chair in Functional Materials and Professor in Chemical and Biological Engineering at the University of Sheffield, the process of charging and discharging of a battery is highly complex, often not fully understood. Perhaps this complexity of the problem is one of the reasons why the majority of the people around just ignore it. However, this particular aspect of power supply is what determines the prices of our technology and electric vehicles. It is also one of the most important features that need to be checked when buying something second hand- an electric vehicle or a gadget.

An article on the Telegraph, which inspired me to write this piece, refers to an unofficial talk with Dr Wolfgang Ziebart during the launch of the Jaguar i-Pace. He was asked about his opinion on a brilliant proposal that all second hand electric vehicles come with an independent report on battery life and condition. His response was apparently very positive, however, officially, Jaguar did not issue a statement on the matter, nor did they allow an expert from their team to comment. Basically, their answer came down to- you are responsible for how you charge and use your batteries. After the guarantee period is over, you are on your own.

So let’s talk about the not-so-common facts behind Li-ion batteries that manufacturers or sales representatives would rather not tell you. We will also look into some essential tips that can help prolonging battery life.

 1. The basic principle behind Li-ion batteries

Here on The GreenOptimistic we have covered this topic many times, so I will not go into too much detail now. However, I would like to just go over the basic principle. Li-ion batteries are the lightest of all rechargeable batteries. They have five essential components. An anode and cathode, which store lithium, an electrolyte, which enables the travel of the electrons, a separator and a current collector.

During battery charging, the cathode releases lithium ions, which reach the anode via the electrolyte and the separator. During discharge, these same ions move back from the anode to the cathode- a process, which generates an electrical flow.  Depending on the size, use and type of Li-ion battery, the number of these cycles could be sufficient to power a device or a vehicle for many years.

2. The influence of charge and recharge on battery life

I think I can safely say that we have all experienced the effect of this process in one way or another. If you are a driver of one of the early electric vehicles, you would know very well what I am talking about. Same goes for all of us, who make full use of their electronic devices throughout the day.

Technically what happens inside the battery is that with every charge-discharge cycle, the cathode degrades due to complex mechanical and chemical processes. This degradation is essentially change in volume, or rearrangements of atoms. In addition, the electrolyte could also experience modifications. The so called process of “coating”, during which certain reactions take place in the electrolyte, results in covering parts of the electrode. As a consequence, the ability of the battery to hold the charge decreases. And if this is not enough, simple factors, such as pressure and temperature, could further affect the battery life in one way or another.

3. Do the manufacturers of electric vehicles care?

OK, enough technicalities. Let’s put all this into context. Perhaps the most relevant example here would be the situation with electric vehicles, as these have the highest and fastest positive impact on the environment.

Unfortunately, here the availability of chemical elements plays a crucial role. Many issues have arisen in the past few years from ethical to environmental considerations related to mining and extraction. These of course has taken a big toll on prices.

But of course, car manufacturers have a direct interest to provide a solution to the problem and find alternative ways to prolong battery life. A lot is being said about replacing the cobalt (problematic chemical to extract) with nickel, in the cathodes. In addition, many tests are being conducted on modifying the electrolyte to reduce coating and degradation. Research is still ongoing, however, it is moving in the right direction.

4. Differences between Li-ion batteries in smart phones and vehicles.

For all of us, slightly disappointed by the somewhat questionable performance of the batteries in our smart phones, it is quite reasonable to be skeptical about batteries in electric vehicles.

However, there are some differences, which might tilt the scale in the positive direction a bit.

For starters, the way we use our smartphones is key. Temperature and pressure are not controlled, nor is the way and time we charge the devices. With vehicles, this process is a lot more controlled and there are additional services, provided by manufacturers, that can assist further- such as (a slightly pricey) cell management.

According to the experts, however, the news is good. In the coming decade we can expect a boost in battery capacity to up to five times the current state, and a mileage of an average electric vehicle of 430 miles on a single charge. No one is commenting on pricing, however.

5. Ways to prolong battery life

Many experts agree that experience is key. As users become more accommodated with technology, they will grasp the way of saving and protecting the batteries of their electric vehicles. If you think about it, this is also the case with fuel efficiency in regular cars- we learn how to control our vehicle so that it burns less fuel.

But here is a key tip coming from professor Corr. Charging to 100% is not ideal, as it puts huge pressure on the cathode. Apparently, 80% is the perfect level and if it is sufficient for the daily needs, it would extend battery life.  She hopes that as technology evolves, and more and more smart charging stations appear everywhere, batteries will be automatically limited to 80% charge. Corr also recommends that we do not fully discharge the battery.

Charge vehicle to 80% and do not discharge to 0%

6. The future

In the context of Black Friday, I guess this next comment of professor Corr becomes quite relevant. She believes that people should approach purchasing of electric vehicles in a slightly more need-driven approach. We should think of which vehicle could meet all our requirements in terms of daily commute, on 80% charge.

Efficiency is key, especially if we think of the benefits to both our wallets and the environment.

Images (c) 1. Nissan; 2. Miles Willis/Getty images

(Visited 533 times, 1 visits today)

Like and share

commentsubscribe
1

You may also like


These guys like us. Do you?


Comments

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.