“Something is wrong with my laptop, it’s expanding and the case is beginning to break apart,” said a caller on the phone.
I immediately knew we were dealing with a potentially dangerous lithium-ion battery failure. Now, don’t get me wrong, lithium ion batteries are extremely safe. That said, in the rare event a lithium-ion or lithium-ion polymer battery fails, they have the potential to become extremely dangerous.
Thankfully, lithium-ion batteries and the devices which use them are engineered with consumer safety in mind. For example, batteries and devices have thermal overload protections built-in. Additionally, protections within the integrated circuitry is designed to prevent over-charging or discharging too fast.
Most consumers will never experience a problem with a lithium-ion battery.
Lithium-ion Battery Tradeoff: Reactivity vs High-Charge
To reap the benefits of lithium-ion chemistry batteries, there’s a trade-off.
Alas, lithium (Li) is a highly reactive and flammable element. When exposed to air and moisture from water, it becomes potentially explosive.
However, it’s highly attractive in batteries because of its low atomic mass and ability to hold a high charge. Thus, lithium sports a high power-to-weight ratio. It’s this high power-to-weight ratio that provides us with portable, lightweight consumer electronics.
Afterall, what would we do without our iPhones and laptops?
Lithium-Ion Battery Overcharge
Once presented with the laptop, I identified the battery as a lithium cobalt oxide (LiCoO2) polymer. Thankfully, I was able to remove the battery safely. This specific chemistry is great for energy storage.
In fact, it’s the same chemistry used in the Boeing 787 Dreamliner batteries. As you might recall, the 787 Dreamliner had some early teething issues with their large, industrial size lithium-ion batteries. A Japan Airlines flight followed by an ANA flight had batteries go into thermal runaway. A worldwide grounding of the Boeing 787 followed until safety improvements were made to the battery.
As to the laptop battery, all four cells within the battery were swollen and bulging. The exterior battery casing was structurally compromised. Aside from bulging, thankfully the cells did not vent (rupture) and the battery never reached a state of thermal runaway.
In this case, the battery protections designed to prevent overcharging failed and well, the battery overcharged. Overcharging causes lithium to build-up on the anode and an oxidizing agent on the cathode. This causes instability and a thermal reaction creates heat. Next, the heat causes the gasses inside the battery to expand and the battery begins to expand and swell.
If this reaction continued, there’s the possibility it may have resulted in a thermal runaway. In thermal runaway, the battery cell would vent with an explosive release of the trapped gasses. It’s likely the excessive heat would setoff a chain-reaction sending the other battery cells into thermal runaway.
Swollen lithium-ion batteries are fully of highly pressurized toxic gases and must be treated with care. Safely dispose of the batteries at a lithium-ion battery recycling center. DO NOT toss the battery in the trash, as you’re putting others, including sanitation workers, at risk of injury if the battery vents and explodes.
Now, if a lithium-ion-polymer battery short-circuits or is overcharged, the battery will get hot fast and that’s where problems develop. In fact, overheating may result in an explosion if thermal runaway occurs.
Finally, if you experience a failed lithium-ion battery, protect the battery terminals and keep the battery dry and cool until you’re able to dispose of it safely at a lithium-ion battery recycling center.