What is a Swollen Battery?

Swollen batteries can be found in many devices that use lithium batteries, such as the electric vehicles. There’s also no single cause for a swollen battery. Some are due to manufacturing defects, others are caused by the age of the battery, and still other cases can be caused by misuse, such as not properly exercising the battery over time, or by using the wrong power charger.

In general, a swollen battery occurs when the battery’s cells are overcharged, as lithium-ion batteries “react unfavorably to overcharging”, according to Don Sadoway, Professor of Materials Chemistry at MIT. As Professor Sadoway explained to Electronics Weekly:

There are strict limits on how much current can be put through a lithium-ion cell. During normal charging, you never see metallic lithium, which is inherently unstable. But during overcharging, the lithium builds up faster than it can dissipate. The result is that metallic lithium plates up on the anode. At the same time, the cathode becomes an oxidizing agent and loses stability.

This reaction produces heat, which warms the gasses inside the battery, causing them to expand. Without any space for ventilation, the battery’s case expands with the gasses, distorting and warping its appearance into that swollen look.

Cell designers and manufacturers understand the possibility of this reaction, and design their batteries to withstand quite a bit of expansion. BMS (Battery Management System) built into the battery pack regulate the battery’s charge, and shut off the power if it detects charging levels beyond the battery’s limits. But these safeguards can occasionally fail because of the misuse of the battery, especially the wrong way of charging.

Eight Causes of Battery Swollen from Improper Charging

First: Too Long Charging Time

Statistic shows that 15% out of total swollen battery cases are caused by too long time charging. So please don’t leave your batteries plugged all the time or charge overnight; and it’s ideal to have a smart phone APP to alert you of the time when the battery is fully charged Power has developed the smart battery system with APP shown on your mobile phone, both for iOS and Android.

Second: Too High Charging Current

As explained by Professor Don Sadoway, “there are strict limits on how much current can be put through a lithium-ion cell.” Normally, with few exception of lithium batteries that are built for fast charge, say, some batteries made of LTO cells or Nanophosphate cells, the recommended charging current is 0.2C-0.5C. C represents the multiply of nominal capacity. So, it’s not a good idea to charge with fast charging station too often, because the too large charging current can damage your batteries in the long run.

Third: Use a Wrong or a Damaged Power Charger

Don’t buy cheap third-party knock-off chargers, and don’t use chargers that aren’t rated for the power of your device, even if the charging plugs are interchangeable. A wrong charger is dangerous for your batteries and may cause unfavorable consequences of battery bulge or even explosion. Please use the authorized charger from your battery supplier.

And when the charger is damaged or broken, please stop use it to charge your battery again and source a new replacement charger from your original battery supplier.

Fourth: Long-term Charging under High Temperature Environment

It is prohibited to charge under high temperature environment. If the battery feels hot, please keep it in a cool and ventilated place for cooling down. And charge the battery when the temperature turns to normal.

Fifth: Charge after the Batteries are Damaged

Please stop charging the battery when it is damaged, for instance, from unexpected traffic accidents or a careless drop external force.

Six: A Poor-Quality Battery

Last but not least, a poor quality battery is naturally the main source of a swollen battery. It’s utmost important to choose the good quality and reliable lithium battery supplier to keep safe, both for your electric vehicle and even for your life!

KOK Power Limited is your right choice-the professional and reliable lithium battery supplier!