CURRENT COLLECTOR AND PREPARATION METHOD THEREFOR, SECONDARY BATTERY, BATTERY MODULE, BATTERY PACK, AND POWER CONSUMING DEVICE

1 . A current collector, comprising:

a strength enhancement layer; and

a current collecting layer comprising a first foam metal layer that is stacked and bonded with the strength enhancement layer and a second foam metal layer that is provided on the side of the first foam metal layer away from the strength enhancement layer and is stacked with the first foam metal layer, the second foam metal layer having a porosity greater than that of the first foam metal layer.

2 . The current collector according to claim 1 , wherein

the strength enhancement layer is a sheet-like metal layer; or

the strength enhancement layer is of a mesh structure.

3 . The current collector according to claim 2 , wherein the sheet-like metal layer is provided with a through hole.

4 . The current collector according to claim 1 , wherein the current collecting layers are respectively provided on two sides of the strength enhancement layer, and the strength enhancement layer and the two current collecting layers are provided side by side in a thickness direction of the current collector, the strength enhancement layer being located between the two current collecting layers.

5 . The current collector according to claim 1 , wherein

the first foam metal layer has a porosity of 30% to 60%; and/or

the second foam metal layer has a porosity of 80% to 95%.

6 . The current collector according to claim 1 , wherein

the strength enhancement layer has a thickness of 1-12 μm; and/or

the first foam metal layer has a thickness of 20-100 μm; and/or

the second foam metal layer has a thickness of 20-200 μm.

7 . The current collector according to claim 1 , wherein

the current collecting layer is made of one of copper, nickel, titanium, aluminum, silver, a nickel alloy, a titanium alloy, a silver alloy, and an aluminum alloy.

8 . A preparation method for a current collector, the method comprising:

a bonding step comprising stacking a second alloy foil for forming a second foam metal layer, a first alloy foil for forming a first foam metal layer, and a strength enhancement layer in sequence, and bonding the second alloy foil, the first alloy foil and the strength enhancement layer to form an intermediate body; and

a foam forming step comprising placing the intermediate body in a corrosive solution to remove one or more elements from the first alloy foil and the second alloy foil such that the first alloy foil and the second alloy foil respectively form the first foam metal layer and the second foam metal layer, the second foam metal layer treated with the corrosive solution having a porosity greater than that of the first foam metal layer.

9 . The preparation method according to claim 8 , wherein the corrosive solution includes at least one of a dilute hydrochloric acid solution, an ammonium sulfate solution, an electrolytic solution obtained by mixing H 2 SO 4 and MnSO 4 , an acetic acid solution, a phosphoric acid solution, and a sulfuric acid solution.

10 . The preparation method according to claim 8 , wherein the first alloy foil, the second alloy foil and the strength enhancement layer are bonded by rolling.

11 . A secondary battery, comprising a current collector according to claim 1 .

12 . A battery module, comprising the secondary battery according to claim 11 .

13 . A battery pack, comprising the battery module according to claim 12 .

14 . A power consuming device, comprising the battery pack according to claim 13 .