[Power Tools] Repair Hitachi Koki's battery with Makita! Demonstration of cell replacement!!

Makita and HiKOKI batteries that cannot be charged with Yahoo Auctions or Mercari.
Can you charge it lucky? I will repair the battery I bought with a little hope by replacing the cell.
Soldering to the cell is dangerous, so I welded it with my own spot welder.
The battery-powered welding machine is more powerful, but I decided to use a capacitor-type, considering the location of the battery.
There seems to be a knack for welding, and depending on the pressing condition and voltage, sparks may appear as at the beginning.
The battery is BL1430 for Makita and BSL1430 for Hitachi Koki.
Since it is a 14.4V lithium-ion battery, it contains eight 18650 cells.
※Precautions
Disassembling the battery or replacing the cell may pose a risk of fire.
Since it seems that there is a fire accident with a compatible battery, it is basically safest to use a genuine battery.