Abstract: A streamlined battery pack can contain at least two battery cells. A printed circuit board (PCB) of the battery pack can include a protection control module. The PCB can have castellations along its perimeter in which wires are soldered. The wires can include battery power wires and battery monitoring signal wires. The castellations are sized so that the egress wires can be soldered therein without substantially protruding from the outline of the PCB. The PCB has a surface area that is no greater than an end of the battery pack, and thereby need not exceed the outer diameter of the remainder of the battery pack. The PCB and the other battery pack components may be substantially enveloped in a polyimide material. The components of the battery pack, including the PCB can arranged, sized and configured, such that they do not create protuberances in the enveloping material.