Almost year ago I bought Electrolux PUREi9. Now they multiplicated. (It had some early software issues but now I'm really happy with it) : r/homeautomation
Synergy Digital Vacuum Cleaner Battery, Compatible with Electrolux Pure i9 Vacuum Cleaner, (Li-ion, 7.2V, 2000mAh) Ultra High Capacity, Replacement for AEG OSBP72LI Battery - Walmart.com
Electrolux Pure i9.2 6DGM Robot Vacuum Specifications - Epey UK
2000mAh Electrolux OSBP72LI25 Battery for 900277484 PI91-5SGM 900277264 Pure i9 900277252 ERV7200DB ERV5210IW RX9-2-4STN 9002772 - AliExpress