Lithium-ion batteries: storage, life cycle and recycling
As their composition is currently considered the most ideal, lithium-ion batteries will play an increasingly important role in our future. It's time to get to know them a little better!
Find out in this article:
- What the difference is between lithium and lithium-ion batteries;
- How to store lithium-ion batteries safely;
- What their lifespan is; and
- How exactly they are recycled.
Both lithium and lithium-ion batteries supply our electrical appliances with portable energy. But what is essentially the difference between the two? The fact that one battery has the word "ion" in its name and the other does not, indicates a difference in its complex chemical composition, but for users it basically boils 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 to have a large energy capacity, which makes them long-lasting. Moreover, they can be stored for a long time in an inactive state without losing their charge.
But despite these advantages, there was a need for another type of battery. The main disadvantage of traditional lithium batteries is that we can only use them once. Once they are used, they cannot be recharged. Therefore, in 1991, the lithium-ion battery was introduced, with a different composition and therefore with a number of modified properties.
Lithium-ion batteries have a secondary cell construction (as opposed to the primary one of lithium batteries). As a result, they often do not last as long with single use, but they can be charged frequently. This makes lithium-ion batteries ideal for devices that use a lot of energy and therefore require regular charging, such as laptops, smartphones and now, increasingly, all kinds of electric vehicles.
Lithium-ion batteries sometimes need to be stored for a while, for example when they are waiting to be transported. This calls for a number of safety considerations.
Do you have to store lithium-ion batteries? Then here are some general rules you should follow:
- Store the cells in a dry, well-ventilated area at the recommended temperature. This will extend the batteries’ shelf life.
- Make sure that the contacts of the batteries cannot cause a short circuit. Cover them with tape or with covering provided by the manufacturer.
- Avoid strong vibrations.
- Ensure that the batteries are not exposed to extreme weather conditions and temperature fluctuations.
- Do not place heavy objects on boxes containing lithium-ion batteries.
- Store lithium-ion cells in designated containers, such as the container types listed in the ADR.
- Do not store the cells near flammable, highly flammable or explosive materials.
- Do not store large amounts of batteries if they are not needed.
- Keep damaged and new cells separate.
- Keep a fire extinguisher for lithium-ion batteries close to the batteries.
- Ask the fire brigade for fire prevention advice, to minimise risks in your storage space.
- Make sure that your environmental permit allows for the storage of batteries, and check with your insurance company.
One of the biggest concerns of both distributors and users of lithium-ion batteries is how long they actually last. It is difficult to give a definite answer, as lifespan depends on many different factors, but averages can give us an idea.
An average battery in an electric car has a service life of about 8 years. (Also read: ‘What is the lifespan of an electric car battery?’.) Most manufacturers guarantee that the average capacity will not decrease more than 20% over the 8-year period, but they hope for a longer average lifespan of 10-12 years.
In smaller devices, such as smartphones and laptops, you often see signs of battery wear earlier. Smartphone batteries can already have a reduced capacity after one year.
|Electric cars||8 - 12 years|
|Electric bus||10 - 15 years|
|Electric bike||4 - 6 years|
|Smartphone||2 - 4 years|
|Laptop||4 - 6 years|
What can you do to extend the life of lithium-ion batteries?
Avoid high temperatures. Long exposure to heat reduces battery life.
Never fully charge the battery and make sure it is not completely discharged. Do not go above 90% or below 20%. The fully charged (100%) and completely used (0%) states put more pressure on the battery. Fortunately, a so-called buffer capacity (link in Dutch) is usually pre-programmed into the (internal) battery charger, which automatically prevents excessive pressure on the battery.
Avoid frequent fast-charging. There are more and more fast-charging points for electric cars. This is useful for those who have to travel long distances and recharge on the way, but the high voltage puts more strain on the battery. There are more and more fast-charging points for electric cars. Sometimes the manufacturer recommends to set the charger to maximum 80%, in order to use a smaller part of the battery and make it last longer.
If you work with lithium-ion batteries and are concerned about sustainability, it is interesting to know exactly how 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 big family with different siblings, aunts and uncles, and lithium is the common factor, but the other battery components can differ completely in quantity and even in kind and type. For example, most lithium-ion batteries on the market today have much less cobalt than before, or no cobalt at all. For a recycling company, the exact content and the potential value also determine to a large extent the price it will ask from the supplier of the batteries to be recycled.
Depending on the company that recycles the batteries, the recycling process may look slightly different, but in general we can distinguish three main steps.
Step 1: Dismantling the battery to reduce risks
After collecting your large lithium-ion batteries, they first enter the dismantling process. A team of high-voltage experts prepares the battery by breaking it down into several smaller parts such as modules or cells. Then they go to the recycling company, which further breaks them down into smaller parts: housing, cathode, anode, electrolyte, separator and binder. The components are deactivated in order to minimise the risks of reactions during the recycling process.
At this stage of 'mechanical processing', iron, copper foil, aluminium foil, the separator and the coating materials are extracted, but further refinement is required through pyro- and hydrometallurgy.
Step 2: Recovering the valuable materials
The next step is where the real work happens. Here, the valuable materials are extracted from the battery components through various treatments:
Pyrometallurgy: The recycling company extracts the transition metals from the battery, such as nickel, cobalt and copper, by liquefying the battery components at a high temperature. Lithium and aluminium remain in the slag. Further (costly) steps are required to recover lithium.
Hydrometallurgy: The recycling company recovers pure metals through 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 only one. The approach they choose depends on the materials they wish to recover and the recycling efficiency they want to achieve.
Often one recycling company does the first step and the residual materials are sent on to other recycling companies for further processing and decomposition.
Step 3: Purifying materials
The materials from pyrometallurgical processing are separated fractions of iron, aluminium or copper. However, when they come out of the process, they are not in their 100% pure form, required for recycling. Therefore, a final step is needed: purification. At this stage, the materials are treated by specialised smelters, who can return all elements to their purest form.