What's inside a battery?
Whether it’s your smartphone, e-bike, or grandma’s hearing aid – all batteries operate on the same basic principle. They consist of three main components:
- An energy-rich side (often made of graphite, like the material in pencils)
- An energy-poor side (containing rare metals such as cobalt, manganese, and nickel)
- A liquid layer in between that regulates the flow of energy
When you use a device, lithium ions move from one side of the battery to the other, while electrons travel externally to deliver energy – for example, to power a lamp.
How does a lithium-ion battery work?
Most modern devices use lithium-ion batteries. Lithium is lightweight and can store a lot of energy. During use, lithium atoms lose their electrons, which then provide electrical power. The remaining ions travel through the battery and settle on the opposite side. When charging, this process is reversed.
However, each time this cycle occurs, the internal structure of the battery changes. Barriers form that make it harder for ions to move freely. As a result, the battery’s capacity gradually decreases.
Temperature: the silent battery killer
Battery efficiency is highly dependent on temperature. The ideal operating temperature is around 45 degrees Celsius. In colder conditions (near freezing), battery capacity can drop by tens of percent. But excessive heat is also damaging – and that damage is irreversible.
Fortunately, modern batteries have built-in safety systems that prevent overheating and optimize charging. Still, wear and tear is inevitable.
How many times can you charge a battery?
Battery degradation starts from the very first charge. In the factory, a new battery is tested several times, which immediately reduces its maximum capacity to about 90% – even though your screen still shows “100%”.
On average, a lithium-ion battery can be charged around 500 times before significant capacity loss occurs. After that, it can still be used for another 500 cycles, but less efficiently. If you charge your phone daily, you’ll likely notice a decline in battery performance after about two years.
What can you do yourself?
While battery wear is unavoidable, you can extend its lifespan by following a few simple tips:
- Avoid extreme temperatures
- Don’t always charge to 100%, and avoid letting the battery drain completely
- Use original or certified chargers and cables to ensure proper voltage and current during each charging phase
- Charge your smartphone regularly – topping up is better than waiting until the battery is nearly empty
