Method for producing all solid-state battery, and all solid-state battery

Abstract

It is suppressed that an active material particle enters into or penetrates through a solid electrolyte layer when an active material layer and the solid electrolyte layer are pressed and that short circuits between a cathode and an anode occur. A method for producing an all solid-state battery includes: a first step of stacking an active material layer over at least one surface of a solid electrolyte layer to constitute a stack; and a second step of pressing the stack to constitute a compact, wherein in the first step, the active material layer contains a secondary particle of an active material, and in the second step, the secondary particle is crushed to primary particles by said pressing, the secondary particle being present in an interfacial portion between the active material layer and the solid electrolyte layer.

What is claimed is: 
     
         1 . A method for producing an all solid-state battery, the method comprising:
 a first step of stacking an active material layer over at least one surface of a solid electrolyte layer to constitute a stack; and   a second step of pressing the stack to constitute a compact,   wherein in the first step, the active material layer contains a secondary particle of an active material, and   in the second step, the secondary particle is crushed to primary particles by said pressing, the secondary particle being present in an interfacial portion between the active material layer and the solid electrolyte layer.   
     
     
         2 . The method according to  claim 1 , wherein
 the relation of 0<(X/Y)≤0.1 is satisfied wherein X is a diameter of the primary particle (μm) and Y is a thickness of the solid electrolyte layer (μm).   
     
     
         3 . The method according to  claim 1 , wherein
 in the first step, a first active material layer is stacked over one surface of the solid electrolyte layer, and a second active material layer is stacked over another surface of the solid electrolyte layer to constitute the stack, the first active material layer having an opposing part that is opposite to the second active material layer across the solid electrolyte layer, and an extending part that extends beyond the opposing part in a width direction, the first active material layer containing a secondary particle of a first active material, and   in the second step, the secondary particle of the first active material is crushed by said pressing, the secondary particle of the first active material being present on an interfacial portion between the opposing part of the first active material layer and the solid electrolyte layer.   
     
     
         4 . The method according to  claim 3 , wherein
 in the first step, the second active material layer has an opposing part that is opposite to the first active material layer across the solid electrolyte layer, and contains a secondary particle of a second active material, and   in the second step, the secondary particle of the second active material is crushed by said pressing, the secondary particle of the second active material being present on an interfacial portion between the opposing part of the second active material layer and the solid electrolyte layer.   
     
     
         5 . The method according to  claim 1 , wherein
 in the first step, the stack has unevenness over a surface of the active material layer, the unevenness being caused by the secondary particle, and   in the second step, the secondary particle is crushed to the primary particles by said pressing to reduce the unevenness over the surface of the active material layer in the interfacial portion between the active material layer and the solid electrolyte layer, the secondary particle being present in the interfacial portion.   
     
     
         6 . An all solid-state battery comprising:
 a solid electrolyte layer;   a first active material layer that is provided for one surface of the solid electrolyte layer; and   a second active material layer that is provided for another surface of the solid electrolyte layer,   wherein the first active material layer has an opposing part that is opposite to the second active material layer across the solid electrolyte layer, and an extending part that extends beyond the opposing part in a width direction,   when a cross section of the first active material layer is observed, it is observed that a first active material that is included in the opposing part is constituted of a primary particle, and   the relation of 0<(X 1 /Y)≤0.1 is satisfied wherein X 1  is a diameter of the primary particle of the first active material (μm) and Y is a thickness of the solid electrolyte layer (μm).   
     
     
         7 . The all solid-state battery according to  claim 6 , wherein
 when the cross section of the first active material layer is observed, a number of secondary particles of the first active material which are included in the extending part per unit area is larger than a number of the secondary particles of the first active material which are included in the opposing part per unit area.   
     
     
         8 . The all solid-state battery according to  claim 6 , wherein
 the second active material layer has an opposing part that is opposite to the first active material layer across the solid electrolyte layer,   when a cross section of the second active material layer is observed, a second active material that is included in the opposing part is constituted of the primary particle, and   the relation of 0<(X 2 /Y)≤0.1 is satisfied wherein X 2  is a diameter of the primary particle of the second active material (μm) and Y is the thickness of the solid electrolyte layer.