Why does a smartphone battery swell: 6 main factors identified

A swollen battery is a pretty scary sight. However, when you notice a problem, it's important to cope with panic, understand why it happened, and take a number of important steps to save yourself and your damaged device.

Why does a battery swell

Let's explain how a battery works in simple terms. It has two main components: an anode and a cathode. The anode is usually made of graphite, and the cathode is made of lithium oxide. Between them is an electrolyte that conducts electricity. When your phone's battery is charged, lithium ions move from the cathode to the anode through the electrolyte. When the battery is discharged, the ions move back. This process is repeated over and over again.

Over time, or due to any number of factors, some lithium ions may begin to accumulate on the anode. This can cause the battery to expand in volume because lithium ions take up more space than they would normally use.

So what could have caused this

• Recharging the device. You are swinging, leaving your phone on charge all night? This can lead to excessive heat generation, damage to battery components, and internal short circuit;
• Overdischarge. If you use your phone every time until it is completely discharged and turns off, be prepared for the fact that its battery will soon swell;
• BMS board failure. The most advanced smartphone models are usually supplemented with a special chip for battery protection, which monitors and controls the charge-discharge process to ensure its safe operation;
• Physical damage. If the device falls or receives a strong impact, a crack may form either on the battery itself or on the gadget's case. In this case, the battery will swell – the heat released will “try to escape” outside;
• Using the device in inappropriate conditions. A modern person carries a phone with him always and everywhere to stay in touch 24/7 and keep up with the latest news. However, this is not always good: smartphones and laptops do not like to be in very hot and humid and very cold places. So do not try to take your phone with you to the bathhouse or for a walk in severe frost.

Manufacturing defects can also be the cause of battery swelling – here all the blame and responsibility lies with the device assembler.