It can be charged separately. Airpods come with data ports such as USB-C or MicroUSB, so they can be charged directly by connecting to a charger, regardless of whether the headphones are in the charging bay.
< br >
The Airpods' case acts as a dedicated mobile power source for wireless Bluetooth headphones. When plugging in the data cable to charge, if there is a headset in the box, most devices will give priority to charging the headset, and then replenish the charge of the charging bin after the headset is fully charged; If there is no earphone in the charging bin, the charging bin will be charged separately at this time, disconnect the power, put the earphone into the charging bin, the earphone can be charged through the charging bin.