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Charging Lithium-Ion Batteries: What Are the Risks?

Lithium-ion batteries are a popular choice for sites looking to improve efficiency and reduce operating costs. However, charging them comes with greater than usual risk. 

We’re so used to charging things that most of the time we don’t give it a second thought. Plug it in. Walk away. Come back when it’s fully charged and ready to go. Usually, this isn’t a problem. But with lithium-ion (Li-ion) batteries, you need to be a little bit more careful.

It’s no secret that these rechargeable batteries can explode or catch fire when damaged, but did you know that the same can also happen if they’re left to overcharge?

Coverage of e-scooter and e-bike fires started by Li-ion batteries highlight the growing threat the batteries pose to public safety. On site, your people and your premises are at risk.

“These figures underline the need, once again, for more education and communication about the dangers of lithium-ion batteries found in rechargeable items [...] When these batteries and chargers fail, they do so with ferocity and because the fires develop so rapidly, the situation can quickly become incredibly serious.” James Kelly, the CEO of British Metals Recycling Association (BMRA), ‘Government action urged as new figures show surge in lithium-ion battery fires

Understanding these risks is important if you’re considering investing in Li-ion technology to improve your operations. In this article, learn more about them and how to charge your Li-ion batteries in such a way as to keep your people and your operations safe.

Click to download your copy of our four-step risk assessment checklist for Li-ion batteries.

Lithium-ion battery charging: what are the risks?

Overcharging a Li-ion battery can lead to the formation of dendrites. Without getting too technical, these are tiny, tree-like structures built up from lithium metal. 

Dendrites are typically formed due to repeated charging and discharging of a battery, and overcharging has the same effect. The build-up of dendrites in Li-ion batteries is so dangerous because they can pierce the separator inside the cell, resulting in a chain reaction within the battery capable of triggering a fire or in extreme cases an explosion.

From here, the operational risks are clear, but it’s worth highlighting some additional risk factors to consider in the context of a battery that’s been left to charge:

Batteries left to charge aren’t always monitored. A fire might not be immediately noticed, making it a greater risk.

Batteries are often stored together when charging. A fire or explosion in one cell will damage other batteries around it, triggering a much more serious incident.

Read more: What Do I Need to Prevent a Lithium-Ion Fire?

How to charge a lithium-ion battery safely

There are several guidelines you can follow as best practice to charge your Li-ion batteries as safely and responsibly as possible, thereby minimising the risk of an incident.

  1. It’s crucial to use the correct charger for your device. The correct charger has been designed for safe use with your batteries. An incorrect charger could result in the battery charging in unpredictable ways and more easily overcharge. 

  2. Avoid leaving your device charging unattended. An unattended device has more of a chance of overcharging. If a fire does break out, your response time will be slower.

  3. Charge the batteries in specialist storage solutions. Specialist Li-ion storage solutions such as cabinets or other units are fire-rated and can often be built with power points as well as suppression systems capable of containing Li-ion fires, providing a safe, controlled environment in which to charge your batteries.

  4. Charge to 80%, not 100%. Charging to 100% battery power might seem like the standard way to operate, but not only will this increase the risk of overcharging, it will also wear out your battery more quickly. Instead, consider charging to 80% as standard. Yes, you will have to recharge your batteries slightly more often than if you fully charged them every time, but the risks are lower and a battery charged in this way will have a considerably longer lifespan (in some cases up to 10 years).

  5. Replace any damaged batteries immediately. A damaged Li-ion battery is a serious health and safety risk. They should be replaced immediately and under no circumstances should they be left to charge. 

  6. Always follow the manufacturer’s instructions. The user manual will outline exactly how to use, store, transport, and charge your battery safely.

Related read: Safely Storing Lithium-Ion Batteries: Why Do You Need Specialist Storage?

How to fix a lithium ion battery that won't charge

If your battery won’t charge, don’t try to fix it yourself. Tampering with a battery in any way could damage it, greatly increasing the risk of a fire. By interfering with it, you may also invalidate the terms of your insurance or any manufacturer’s warranties in place. 

Again, because if you take nothing else away from this resource, let it be this:

Do not charge a damaged Li-ion battery or a Li-ion battery that has been in any way compromised.

Check to see if your warranties cover faulty batteries, in which case they can be returned to the manufacturer and either professionally repaired or replaced.

If the battery is faulty and you have to dispose of it, do so responsibly, in line with correct disposal procedures for Li-ion batteries.

Have you left your Li-ion batteries on charge?

While Li-ion batteries are a popular choice for improving efficiency and reducing operating costs, the greater-than-usual risks that come with charging them make it crucial that you follow the correct safety procedures.

Using the correct charger for your device is a good start and will cost you nothing, as is ensuring your people are trained on charging best practices such as never to leave the batteries charging unattended. 

For larger operations (in scale or battery power), our specialist storage solutions with built in charging points will demonstrate your commitment to health and safety and responsible business practices. So even in the absence of consistent Li-ion regulations you’ll have taken the necessary precautions to ensure that your batteries are charged safely and your operations can benefit from all the advantages unlocked by modern Li-ion technology.

To download your copy of our four-step risk assessment checklist for lithium-ion batteries, click here.