Electronic devices and batteries - Lufthansa

What the official page says

Power banks are not classified as portable electronic devices. Power restriction: each power bank max 100 Wh or 2 g LC. Item limit: max 2 power banks per passenger. Charging power banks or using power banks is prohibited (approved medical devices exempt). Power banks must not be placed in overhead compartments; store under the front seat or in the seat pocket. For power banks between 100 Wh and 160 Wh, airline transport approval is required. Spare batteries table: up to 100 Wh / max 2 g LC - 20* items, carry-on YES, checked NO (*includes all battery types: non-spillable wet, dry cell, gel cell, lithium and power banks); >100 Wh up to 160 Wh - 2 items, approval required; >2 g up to 8 g LC - 2 items, medical devices only.