Current collector, negative pole piece, secondary battery and electric device

The invention relates to the field of secondary batteries, in particular to a current collector, a negative pole piece, a secondary battery and an electric device. The current collector comprises the iron-nickel alloy substrate layer and the copper layer arranged on at least one side of the iron-nickel alloy substrate layer, the bonding force between the current collector and an active substance can be improved, meanwhile, the mechanical strength of the current collector is guaranteed, and therefore the cycle performance of the corresponding battery is improved.