Ok, thats solder 
yeah thats how i make them also, a big dab of solder on top of the wire bypass on the spring sanded flat 
But yours where so tidy & round i didnāt recognize it for what it was.
The Efest purple 26650 battery should easily supply what ever the driver is letting through, the only āhotterā battery i know of is the green Efest 26650, but that is only 0.3A more capable.