Power banks are becoming popular and handy. They are useful devices for charging our cell phone batteries when we are on the road and away from power outlets, but improper use could lead to disasters.

In an interview conducted by Ming Pao, Dr. Denis Yu, Associate Professor, explained the details and workings of the lithium-ion battery inside a power bank. The actual available capacity of the power bank is in fact lower than that being displayed on the power bank because of the difference in voltage between the lithium-ion battery (3.7V) and USB system (5V). Keeping the battery capacity between 20% and 80% without overcharging the battery can extend its life. Whereas fast charging is not recommended as it will increase the temperature of the power bank and accelerate side reaction, causing the battery to degrade faster. Proper usage and storage of the power banks are also recommended to ensure safety. For example, it is essential to use specified transformers and cables to reduce chance of accidents.

Article links:
https://news.mingpao.com/pns/%E5%89%AF%E5%88%8A/article/20210413/s00005/1618251682338
https://news.mingpao.com/pns/%E5%89%AF%E5%88%8A/article/20210413/s00005/1618251683407
https://news.mingpao.com/pns/%E5%89%AF%E5%88%8A/article/20210413/s00005/1618251684485