Causes of Damage The 
laptop battery has been used for a long time, and it has often been insufficiently charged, and even shows that the battery has been damaged. The specific performance is that the internal resistance becomes large, and the voltage at both ends rises faster when charging. This is easily judged to be full by the charging control circuit, and the capacity is naturally reduced. Because the internal resistance of the battery is relatively large, the voltage drop during discharging is large and the speed is fast, so the system easily misunderstands that the voltage is insufficient and the power is insufficient. When it is found that the battery operating time is relatively short, appropriate measures should be taken. 
Refresh Program 
Brand laptops have battery refresh programs that we can use to repair the battery. For example: An IBM Thinkpad 390/262650 notebook computer, equipped with a nickel-metal hydride (Ni-Mh) battery, due to improper normal charge and discharge, resulting in shorter and shorter battery discharge time, leaving less than 5 minutes, if It is very inconvenient to carry a notebook computer out to work. What methods can be used to restore the battery discharge time? 
In view of the above situation, we can use the battery refresh program introduced by IBM to refresh the battery and restore the discharge time. The specific method is as follows: . 
(1) Using AC power to power laptops, first download IBM's refresh program for TP390/390e/390x laptop batteries. 
(2) Restart the computer, press F8 to enter the boot menu, and select the safe DOS mode. 
(3) Enter the directory where the file was just downloaded, execute the battery refresh program isbr0lww, exe, read the warning message, insert the floppy disk as required, and press the Enter key to perform the self-extracting operation. 
(4) Use this floppy disk to boot the computer. The screen appears Starting PC-DOS. . . Prompt information. 
(5) Unplug the AC power source according to the prompts and the program will automatically discharge the Ni-Mh battery. After the discharge is completed, the system will automatically shut down. 
(6) Since the battery temperature is high at this time, the battery should not be turned on immediately. After the battery is cooled for a while, plug in the AC power.
(7) Boot the computer with a floppy disk, this time Autoexec. The bat file will automatically run the refresh program and ask the user whether to proceed. After selecting yes, press Enter. 
(8) At this point, the refresh process begins to refresh the battery. The process is very fast. When you return to the DOS prompt A:>, the refresh is complete. 
(9) Turn off the computer and charge the battery until the indicator lamp turns green. 
(10) The above process is repeated 3 times to get the best results. 
In addition, many lithium battery failures are caused by the failure of a battery cell in the battery pack. This phenomenon cannot be avoided. Because the nature of the cells in each cell is not likely to be exactly the same, some of the cells will begin to deteriorate after a long period of time, destroying the overall (after series) discharge curve. Interested and capable readers can try to open the battery pack, with the help of a multimeter, you can quickly find the damaged cell (abnormal voltage). If conditions permit, replace qualified products according to the corresponding parameters of the cell.