Power banks have long become a "life-saving artifact" for modern people to travel, but many people have misunderstandings about their use: some people are used to plugging them in as backup power, some people leave them idle for a long time after they are fully charged, and some people even treat power banks as "permanent plug-in devices." Are these behaviors really safe? Will long-term plugging in damage the power bank? This article will analyze the plug-in risks of power banks based on the principle of lithium batteries and provide a scientific maintenance guide.
I. The core of power banks: the two sides of lithium batteries
Power banks generally use lithium-ion batteries or lithium polymer batteries, and their characteristics determine the taboos of use:
a. Fear of overcharging and over-discharging: long-term storage with full or empty power will accelerate aging.
b. High temperature is an invisible killer: continuous plugging in may cause internal circuits to heat up.
c. Self-discharge is inevitable: even if not used, 1%-5% of the power will be naturally lost every month.
Key conclusion: The original intention of the power bank design was "mobile power supply" rather than a long-term plug-in device.
II. Four major risks of always plugging in
1. Overcharge protection is not absolutely reliable
- Original power bank: Most of them have overcharge protection and automatically cut off the power after full charge.
- Poor quality power bank: The circuit design is simple, and it may continue to "trickle charge", causing the battery to overvoltage and bulge.
- Laboratory data: A third-party test showed that among 10 low-priced power banks, 3 continued to charge with a micro-current after being fully charged, and the battery temperature increased by 8°C-12°C.
2. High-voltage static accelerated aging
- Maintaining 100% power for a long time will aggravate the decomposition of the electrolyte, and the capacity decay rate is 3-5 times that of 50% power storage (data source: Battery University).
3. Circuit components continue to heat up
- Even if charging is stopped, the buck/boost module of the power bank in the plugged-in state may still work, causing component aging or even short circuit.
4. Safety hazards
- Long-term plugging in + high temperature environment (such as in a car with direct sunlight) may cause thermal runaway, and in extreme cases, cause combustion.
III. Scientific use guide: balance convenience and safety
✅ Correct approach
a. Charge as you use and power off in time
- Unplug the power bank when it is charged to 80%-90% to avoid long-term full charge.
- If you need to plug in for a long time (such as emergency standby), choose a smart power bank that supports automatic power off function (such as Anker PowerCore Reserve).
b. Activate the battery regularly
- Use it at least once a month to complete a 20%-80% charge and discharge cycle to prevent battery "passivation".
c. Keep half the power before storage
- When not in use for a long time, charge it to 50%-60% and then turn it off and store it away from high temperature and humid environment.
❌ Avoid behavior
- Treat the power bank as a "permanent plug-in device" (such as plugging it into the socket as a fixed charger for mobile phones).
- Long-term idleness (more than 3 months) in a fully charged state.
- Use while charging (charging the power bank and powering the mobile phone at the same time), which will increase the circuit load.
IV. Ultimate advice: safety is more important than convenience
The essence of a power bank is an "energy carrier" rather than an "energy storage device". For safety and life, please follow the following principles:
a. Do not overcharge: unplug the battery when it is fully charged, and avoid long-term plugging.
b. Do not store it at high temperatures: keep it away from heat sources and avoid storing it in the car in summer.
c. Do not be greedy for cheapness: choose well-known brands and refuse products without any warranty.
Remember: The battery health of a power bank directly affects safety. If you find that the battery life is sharply reduced, abnormal heating or deformation of the appearance is found, please replace it immediately!
