Lithium-ion batteries: storage, lifespan, and recycling
We can no longer ignore it: lithium-ion will power a large part of our future. Applications with lithium-ion batteries are becoming increasingly numerous, just think of the booming market for electric vehicles, home batteries, and all sorts of other energy storage solutions.
As their composition is currently considered the most ideal, lithium-ion batteries will play an increasingly larger role in our future. So, it's time to get to know them better!
What is the difference between a lithium and lithium-ion battery?
Both lithium and lithium-ion batteries provide our electronic devices with portable energy. But what is actually the difference between the two? The fact that one battery includes the word 'ion' in its name and the other does not, already indicates a difference in the complex chemical composition, but for users, it essentially comes down to this: lithium-ion batteries are rechargeable and lithium batteries are not.
Lithium batteries have been on the market for half a century, and are known for having a large energy capacity, which allows them to last a long time. Moreover, they can be stored in an inactive state for a long time without losing their charge.
But despite those advantages, there was a need for a different type of battery. The biggest disadvantage of traditional lithium batteries is that they can only be used once. When they are depleted, they cannot be recharged. Therefore, in 1991, the lithium-ion battery was introduced, with a different composition and thus a number of modified properties.
Lithium-ion batteries have a secondary cell construction (unlike the primary cells of lithium batteries). Therefore, they often last shorter on a single use, but they can be frequently recharged. This makes lithium-ion batteries ideal for devices that use a lot of energy, and therefore require regular recharging, such as laptops, smartphones, and now increasingly various types of electric vehicles.
How is the safe storage of lithium-ion batteries managed?
Lithium-ion batteries sometimes need to be stored for a while, for example, when they are waiting to be transported. This requires a number of safety considerations.
If you need to store lithium-ion batteries yourself, here are some general rules you should follow:
- Store the cells in a dry, well-ventilated area, at the recommended temperature. This extends the shelf life of the batteries.
- Ensure that the battery contacts cannot cause short circuits. Cover them with tape or with the manufacturer's cover.
- Avoid strong vibrations.
- Ensure that the batteries are not exposed to extreme weather conditions or temperature fluctuations.
- Do not place heavy objects on boxes containing lithium-ion batteries.
- Store lithium-ion cells in containers designed for that purpose, such as the container types listed in the ADR.
- Do not store the cells near flammable, easily ignitable, or explosive materials.
- Do not store large quantities of batteries if it is not necessary.
- Keep damaged and new cells separated.
- Keep a fire extinguisher for lithium-ion batteries near the batteries.
- Consult the fire department for advice on fire prevention, to minimize the risks in your storage area.
Ensure that your environmental permit includes the storage of batteries.
What is the lifespan of lithium-ion batteries?
One of the biggest concerns of both distributors and users of lithium-ion batteries is: how long do they actually last? It's difficult to give a definitive answer, as the lifespan depends on many different factors, but averages can give us an idea.
In smaller devices, such as smartphones and laptops, signs of battery wear can often be seen quickly. Smartphone batteries may have reduced capacity after just one year.
On average, a battery in an electric car has a lifespan of about 8 years. Most manufacturers guarantee that the average capacity will not decrease by more than 20% over a period of 8 years, but they hope for a longer average lifespan of 10-12 years.
What can you do yourself to extend the lifespan of lithium-ion batteries?
- Avoid high temperatures. Prolonged exposure to heat shortens the battery life.
- Never fully charge the battery and ensure it doesn't completely discharge. Stay above 20% and below 90%. Fully charged (100%) and fully depleted (0%) states put more stress on the battery. Fortunately, a so-called buffer capacity is usually pre-programmed in the (internal) charger of the battery, which automatically prevents too much pressure on the battery.
- Avoid frequent fast charging. For electric vehicles, there are increasingly more fast-charging stations. This is convenient for those who need to travel long distances and recharge on the go, but the high voltage puts more pressure on the battery. Sometimes the manufacturer advises setting the charger to a maximum of 80% to use a smaller portion of the battery and make it last longer.
How are lithium-ion batteries recycled?
If you work with lithium-ion batteries and are concerned about sustainability, it's interesting to know how exactly they are recycled and which raw materials are recovered from them. Here it is also important to mention that lithium-ion batteries are actually one large family with various brothers and sisters, aunts and uncles, and lithium being the common factor, but the other components of the batteries can completely differ in quantity and even in kind and type.
For instance, most lithium-ion batteries that come onto the market today contain much less cobalt than before, or even none at all. For a recycler, the exact composition and potential value largely determine the price they will charge the provider of the batteries that need to be recycled.
Depending on the company that recycles the batteries, the recycling process can look slightly different, but generally we distinguish three main steps.
Step 1: Dismantling the battery to reduce risks
After the collection of your large lithium-ion batteries, they first go through dismantling. A team of high-voltage experts prepares the battery by breaking it down into smaller components such as modules or cells. Then, they go to the recycler, who further splits them into smaller parts: casing, cathode, anode, electrolyte, separator, and binder. The components are deactivated to minimize the risks of reactions during the recycling process.
At this stage of 'mechanical processing', iron, copper foil, aluminum foil, the separator, and the coating materials are extracted, but further refinement is needed through pyro- and hydrometallurgy.
Step 2: Recovering Valuable Materials
The next step is where the real work happens. Here, valuable materials are extracted from the battery components through various treatments:
- Pyrometallurgy: The recycler extracts transition metals from the battery such as nickel, cobalt, and copper by melting the battery components at high temperatures. Lithium and aluminum remain in the slag. Further (costly) steps are required to recover lithium.
- Hydrometallurgy: The recycler recovers pure metals using a process involving chemical solvents.
Each recycling company has its own unique process. Some use both methods in combination with the mechanical processing from the first step, while others use just one. The approach they choose depends on the materials they wish to recover and what recycling efficiency they aim to achieve.
Often, one recycler does the first step and then sends the remaining materials to other recycling companies for further processing and decomposition.
Step 3: Purifying Materials
The materials from pyrometallurgical processing are separated fractions of iron, aluminum, or copper. However, when these materials emerge from the process, they are not in their 100% pure form, which is necessary for reuse. Therefore, a final step is required: purification. At this stage, materials are treated by specialized smelters who can refine all elements back to their purest form.
