If you have replaced the battery before, and after that, the symbol of unknown parts appears on the battery icon, then you can try to plug and unplug the battery again. This is likely to solve the problem, because sometimes poor battery contact will lead to this problem.
2. Clear the battery data
If repositioning the battery does not solve the problem, you can try to clear the battery data. On the battery usage page, you can see the detailed information and usage of battery data. Resetting battery usage will clear all recorded battery data, thus solving the problem.