Makita BL1813G Battery Issues: Damaged Cells, LGDAHA31865 Replacement & Soldering Options

I warmly welcome,
Actually, since I bought a screwdriver (HP457D), I had a problem with one battery (I bought it as an exhibition one, so the warranty was off). The battery, after being charged with the charger, was quickly discharged, and when I left it after charging, e.g. for a day, it did not work in the screwdriver at all. I decided to undress her and noticed. that there were leaks from the cells ... I don't know why, because I keep it at home all the time and it looked like new at the time of purchase. The charger (DC18WA) does not indicate a damaged battery, so I think it can be regenerated as much as possible and here are 2 questions:
1. LGDAHA31865 cells are inserted in the battery, unfortunately I could not find them for purchase. Can they be replaced with others? Can I use higher capacity cells, e.g. 2500mAh?
2. I know that it is recommended to weld the cells with a spot welding machine, but I do not have one and if I solder the cells trying to do it as quickly as possible, is there a chance that I will not damage them? What soldering temperature do you recommend?

Thank you in advance
Paul

Hello.
Let me answer question 2 by providing a link to the topic of stress-free soldering of Li-Ion cells and similar: https://www.elektroda.pl/rtvforum/topic3230863.html
greetings

Thank you - then I can handle the soldering. The only thing left is to replace the batteries. Has anyone experience with this battery? You can find videos in which, for example, people put 3000mAh batteries into a Bosch 1500mAh battery and it looks that the charger "accepts" them ...

I see that the willingness to share knowledge on this topic is negligible, so I decided to run a test.
At this point, I can confirm that inserting other cells (also 1850) with a higher capacity (I used 2000mAh found in Samsung's drawer) works properly and the screwdriver works, and the charger has no problems with "accepting" the new battery.
greetings,
Paul