Original battery: 
Lipo (lithium polymère) 3.7V / 480mAh
-GJ451860	1.776Wh

Dimensions:  4,5mm x 17,25mm x 61mm 

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Dimention Max: 61*20*4,5mm.

Link to buy battery replacement:

4,5mm x 18mm x 60mm (451860): https://www.aliexpress.com/i/1005007218624706.html

4mm x 20mm x 60mm (402060): https://www.aliexpress.com/item/32916572795.html

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Tuto: https://www.youtube.com/watch?v=zXJ1l8M9nAI