The answer upstairs is 18650. The questioner should ask about the difference between 18505 and 26500. Let's take Fuant ER18505 and ER26500 as examples. These column batteries are non-rechargeable lithium batteries, and the voltages of both are the same. is 3.6V. The difference is that the volume is different. The first two numbers are the diameter and the last three numbers are the height. The larger the volume, the larger the capacity. is 4000 mAh and the capacity type ER26500 is 8500 mAh.
The 18500 lithium battery will expand after use.
Lithium battery expansion is commonly referred to as “bulge.”
There are two reasons. The first is the problem of battery manufacturing level, uneven electrode coating and production. the manufacturing is relatively crude. To put it simply, the quality of the lithium battery itself is notpretty good ; the second problem is overcharging and overdischarging during use. These two factors will cause a violent short circuit-like reaction inside the battery during use, generating a large amount of heat, which in turn will cause the electrolyte to decompose and vaporize, causing a swelling of the battery.
Based on the situation you described, it should be an overload problem.
If the battery is bulged, please stop using it. Continuing to use an inflated battery will significantly increase the risk of explosion.