I. Digital Password: The Naming Logic of 18650
The sequence of numbers 18650 is like the identification number of a battery. Each digit has a specific meaning:
The first two 18: indicate that the diameter of the battery is 18 millimeters.
The two middle digits "65": indicate that the battery length is 65 millimeters.
"Zero at the end": Indicates that it is a cylindrical battery.
This naming convention originated from early industrial standards, similar to the Type-A/B/C classification of USB interfaces, making it convenient and quick to identify battery specifications.
II. Structure Unveiled: The Precise Design of a Tiny Body
When the outer casing of the 18650 battery is removed, you will find a sophisticated "sandwich" structure hidden inside:
Steel casing: 0.25mm thick armor to prevent electrolyte leakage
Spiral electrode sheet: The positive and negative electrodes are tightly wound like a Swiss roll, and when unfolded, they can reach 1.5 meters in length.
Intelligent protection board: The built-in "fuse" will automatically cut off the circuit when overcharging occurs.
Ceramic diaphragm: A 20-micron thick safety barrier that can withstand temperatures up to 150℃
III. The "Battery Pioneer" Everywhere
From pockets to space, the 18650 battery can be found everywhere:
Power tools: The instantaneous power of an electric drill is equivalent to that of 10 AA batteries.
Laptop: 6 batteries connected in parallel can support 8 hours of work.
Emergency power supply: 10 cells connected in series can power the camping lamp for 3 days.
New energy vehicles: The early models of Tesla used over 7,000 18650 batteries.
Spacecraft equipment: The backup power system of the International Space Station also uses it.
