Stacked all-solid-state battery and method of manufacturing the same

1. A stacked all-solid-state battery comprising:

a plurality of all-solid-state batteries, each of the all-solid-state batteries including a cathode layer that has a cathode current collector and a cathode active material layer containing at least a cathode active material and formed on the cathode current collector, an anode layer that has an anode current collector and an anode active material layer containing at least an anode active material and formed on the anode current collector, and a solid electrolyte layer disposed between the cathode active material layer and the anode active material layer and containing a solid electrolyte having at least a lithium ion conductivity, wherein

the plurality of all-solid-state batteries are stacked,

the cathode current collectors and the anode current collectors of the plurality of all-solid-state batteries include a plurality of uneven portions, respectively, on surfaces perpendicular to a stacking direction of the plurality of all-solid-state batteries,

the plurality of all-solid-state batteries include two adjacent all-solid-state batteries, the two adjacent all-solid-state batteries being configured such that the cathode current collector of one of the two adjacent all-solid-state batteries is directly joined to the anode current collector of an other one of the two adjacent all-solid-state batteries,

a void is present at an interface between the cathode current collector of the one of the two adjacent all-solid-state batteries and the anode current collector of the other one of the two adjacent all-solid-state batteries,

the plurality of uneven portions of the cathode current collector of the one of the two adjacent all-solid-state batteries are at least partially engaged with the plurality of uneven portions of the anode current collector of the other one of the two adjacent all-solid-state batteries, and

an interfacial void at an end portion of the stacked all-solid-state battery in the stacking direction is smaller than an interfacial void at a central portion of the stacked all-solid-state battery in the stacking direction.

2. The stacked all-solid-state battery of claim 1 ,

wherein a surface of the cathode current collector of the one of the two adjacent all-solid-state batteries has an arithmetic average roughness of greater than or equal to 0.1 μm and less than or equal to 10 μm, the surface opposing another surface of the cathode current collector of the one of the two adjacent all-solid-state batteries, the another surface being adjacent to the cathode active material layer of the one of the two adjacent all-solid-state batteries.

3. The stacked all-solid-state battery of claim 1 ,

wherein a surface of the anode current collector of the other one of the two adjacent all-solid-state batteries has an arithmetic average roughness of greater than or equal to 0.1 μm and less than or equal to 10 μm, the surface opposing another surface of the anode current collector of the other one of the two adjacent all-solid-state batteries, the another surface being adjacent to the anode active material layer of the other one of the two adjacent all-solid-state batteries.

4. A method of manufacturing a stacked all-solid-state battery, the method comprising:

preparing a plurality of all-solid-state batteries, each of the all-solid-state batteries including a cathode layer that has a cathode current collector and a cathode active material layer containing at least a cathode active material and formed on the cathode current collector, an anode layer that has an anode current collector and an anode active material layer containing at least an anode active material and formed on the anode current collector, and a solid electrolyte layer disposed between the cathode active material layer and the anode active material layer and containing a solid electrolyte having at least a lithium ion conductivity; and

stacking the plurality of all-solid-state batteries,

wherein the cathode current collectors and the anode current collectors of the plurality of all-solid-state batteries include a plurality of uneven portions, respectively, on surfaces perpendicular to a stacking direction of the plurality of all-solid-state batteries,

wherein the plurality of all-solid-state batteries includes two adjacent all-solid-state batteries,

wherein in the stacking, the plurality of all-solid-state batteries are stacked such that the cathode current collector of one of the two adjacent all-solid-state batteries is directly joined to the anode current collector of an other one of the two adjacent all-solid-state batteries,

wherein a void is present at an interface between the cathode current collector of the one of the two adjacent all-solid-state batteries and the anode current collector of the other one of the two adjacent all-solid-state batteries,

wherein the plurality of uneven portions of the cathode current collector of the one of the two adjacent all-solid-state batteries are at least partially engaged with the plurality of uneven portions of the anode current collector of the other one of the two adjacent all-solid-state batteries, and

wherein an interfacial void at an end portion of the stacked all-solid-state battery in the stacking direction is smaller than an interfacial void at a central portion of the stacked all-solid-state battery in the stacking direction.