The big end you're talking about is the positive electrode, which is difficult to solder. The heating time should not be too long, a few seconds maximum. If it is too long, it will damage the diaphragm inside. Battery cell. If damaged, the battery will be useless. Use an old-fashioned soldering method. For a great guide on soldering irons, you can check out Feike's tutorials. They all have photos and are very detailed!
A123 lithium iron phosphate battery welding problem
Introduction Welding of A123 lithium iron phosphate battery The big problem you mentioned is the positive electrode, which is difficult to weld. The heating time should not be too long, a few seconds maximum. If it is longer, it will damage the battery. inside the bat