LEGO has a mysterious new rechargeable battery, what can be the product? - RacingBrick
Batteries and Battery packs
BrickLink - Part 87513c02 : LEGO Electric 9V Battery Box Power Functions (Non-Rechargeable) with Red Bottom [Electric, Battery Box] - BrickLink Reference Catalog
Amazon.com: LEGO Power Functions AAA Battery Box 88000 : Toys & Games
LEGO Power Functions Rechargeable Battery Box 8878 - Walmart.com
AAA Battery Box Building Block Accessories Compatible for LEGO for Children - Walmart.com
Batteries and Battery packs
Build your LiPo rechargeable battery for Control+ and Powered Up hubs. - LEGO Technic, Mindstorms, Model Team and Scale Modeling - Eurobricks Forums
Power Function Rechargeable Battery 8878 - General LEGO Discussion - Eurobricks Forums
Rechargeable Battery Box 8878 -1 54599 Moc Building Blocks Cars Motor Toys Compatible With 84599 64227 58122 58123b Parts Toys - Blocks - AliExpress