All-solid-state battery and method of manufacturing all-solid-state battery

An all-solid-state battery, comprising:

• a negative electrode layer and a positive electrode layer laminated together with a solid electrolyte layer interposed therebetween, the positive electrode layer including a positive electrode active material layer and a positive electrode current collector layer, wherein
• a direction in which the negative electrode layer and the positive electrode layer are laminated is defined as a laminating direction, and one direction among directions orthogonal to the laminating direction is defined as a first direction,
• the positive electrode current collector layer includes a positive electrode current collector layer-main body and a positive electrode tab, the positive electrode current collector layer-main body overlapping with the positive electrode active material layer in the laminating direction, the positive electrode tab extending from the positive electrode current collector layer-main body toward one side in the first direction,
• the positive electrode current collector layer is constituted of a polycrystalline body,
• a first region defined in the positive electrode tab and including a boundary portion between the positive electrode tab and the positive electrode current collector layer-main body has an average grain size of the polycrystalline body that is larger than an average grain size of the polycrystalline body of the positive electrode current collector layer-main body, and
• the average grain size of the polycrystalline body in the first region is less than 3.0 μm.