TECCPO 20V MAX 4.0 Ah Lithium Ion Large Capacity Battery-Pack, Rechargeable Replacement Battery, for All 20V TECCPO/POPOMAN Cordless Power Tools - - Amazon.com
Lithium Ion Battery Pack - 3.7V 6600mAh : ID 353 : $24.50 : Adafruit Industries, Unique & fun DIY electronics and kits
Cell to Pack - Battery Design
Cable connecting systems and accessories | BBC Cellpack GmbH