Lithium-ion batteries can be dangerous when not stored correctly, so it’s important to understand the risks involved and what correct storage looks like.

A shelved battery is not necessarily a safe battery. In particular, lithium-ion cells can catch fire or even explode if they’re damaged or exposed to high temperatures during storage.

“As well as the increasing danger of fire in residential properties, AXA is also alerting commercial businesses, such as shopping centres, retailers and e-bike and scooter storage and repair facilities, about the risks posed by these batteries,” writes the insurer.

Where official government guidance is still lacking, businesses should listen to what other relevant bodies are saying, in this instance to ensure their operations are protected and the terms of their insurance valid. In other words, how you store your batteries really matters.

But you’re in a busy workplace: there’s no shortage of things that could damage them. How can you safely store your batteries in these conditions, where a simple mishap could set them off? In this week’s article, discover the dangers surrounding lithium-ion battery storage and how to store your batteries correctly to keep your operations and your people safe.

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The dangers of storing lithium-ion batteries

Just as it’s easy to overlook the risks that come with charging lithium-ion (Li-ion) batteries, users often fail to consider the potential dangers that come with trying to store them safely.

Li-ion batteries contain flammable electrolytes that can ignite if the battery is damaged or exposed to extreme temperatures. Because of the substances involved, Li-ion fires burn very hot, very rapidly. Fires of this kind are notoriously difficult to extinguish and pose a real threat to your people — not to mention your ability to continue day-to-day operations.

“Fires involving lithium batteries are the fastest growing fire risk in London.” London Fire Brigade, ‘Lithium Batteries’

At time of writing, guidance around the safe use of Li-ion batteries is inconsistent at best, putting the responsibility for the safe use of these batteries firmly in your court. To protect your people and keep your operations running, you will want to take several precautions.

Key considerations when storing lithium-ion batteries

“Businesses must ensure they have put in place reasonable precautions,” AXA explains, which include having “reviewed and updated existing fire risk assessments and purchased specific fire extinguishers designed for use on fires involving lithium batteries.”

These are excellent places to start, but there are several other considerations you might want to make when looking at how to store your batteries safely and responsibly.

Storing Li-ion batteries fully charged

If you read our recent article on the risks surrounding charging Li-ion batteries, you’ll know you shouldn’t really be fully charging your batteries anyway if you want to maximise their lifespan.

With this in mind, it’s advisable to store lithium-ion batteries at around 50-80% charge. As well as the gradual stress (and reduction in performance) that you’ll subject your batteries to if you repeatedly fully charge them and leave them in storage, doing so puts you at risk.

An overcharged battery is more likely to overheat and catch fire compared to a battery that has been charged at, say, 50% or 80% of its capacity. The last thing you want is a fire or explosion in your battery store, so this is something to consider.

Li-ion battery storage and temperature

Heat is one of the main triggers of thermal runaway — the term used to describe the reaction inside an Li-on battery that leads to fire or an explosion. Often, this comes about as a result of physical damage or overcharging (see above) but simply exposing the battery to too great a temperature can have the same effect — especially if it’s left to sit and sweat.

To prevent this, it’s important to store lithium-ion batteries in a cool, dry place.

Can lithium-ion batteries be stored in the cold?

The opposite temperature extreme is also risky. Cold temperatures (below 0 degrees) can compromise the battery's components, so you’ll want to avoid this, too.

If you’re currently storing your batteries in a warehouse, for example, you’ll want to make alternative arrangements for the winter before the mercury drops and colder weather sets in.

All things considered, a temperature-controlled environment is best for your batteries — not too hot, not too cold, with the control and the visibility you need to keep them just right.

Storing Li-ion batteries with other metals/materials

Because Li-ion batteries are so reactive, storing them in close proximity to other metals or conductive materials is not advised. This can lead to short circuits and the potentially dangerous situations we’ve already referenced numerous times above.

If stored near to other combustible materials, ensure a separation of 2.5m minimum.

Given these storage requirements, a specialist storage solution designed specifically for storing Li-ion batteries is going to provide your people with the best protection. What do these solutions look like and how should you choose the right ones for your operations?

Specialist storage solutions for Li-ion batteries

From cabinet-sized units to walk-in rooms, Li-ion storage solutions come in a wide range of types.

To store your batteries as safely as possible, it’s important to match your batteries with the appropriate energy storage and safety requirements. Generally speaking, the bigger the battery, the bigger the risk, so understanding your batteries’ needs is time well spent.

By way of an example, our Lithium-Ion Battery Storage cabinet offers the following:

Engineered from fully seam-welded steel for maximum protection.
In the event of an incident, a hazardous gas extraction system clears the air.
A suppression system kicks in to help control and contain the spread of fire.
Separate battery trays are used for discrete suppression.
Every unit is fire-rated to at least 90 minutes of protection, amongst the highest rating commercially available, so you can be confident that the explosion and the resulting fire is contained while thermal detection systems alert you to the incident.

To find out more about identifying the right storage solutions for your Li-ion batteries, check out our dedicated article on the subject.

Storing your lithium-ion batteries safely

As reported incidents of fires started by Li-ion batteries continue to grow, even smaller businesses with limited use of these battery types should strongly consider, and at the very least review, how they’re storing them when they’re not in use. For their part, large, multi-site operations can trip up on the fact that these battery types aren’t yet properly regulated.

AXA is just one example of an external body expecting businesses themselves to take responsibility for the Li-ion batteries they’re using and the risks they pose. How are you storing your Li-ion batteries, and could you be storing them more safely?