Method for producing secondary battery having negative electrode with different surface roughnesses

A method for producing a secondary battery that is a non-aqueous electrolyte secondary battery including a flat wound electrode body in which a positive electrode plate and a negative electrode plate are wound with a separator interposed therebetween,

• the negative electrode plate including a negative electrode core made of a copper foil or a copper alloy foil and a negative electrode active material mixture layer on each surface of the negative electrode core,
• the negative electrode core having a first surface and a second surface opposite the first surface, wherein a surface roughness of the first surface is less than a surface roughness of the second surface,
• the negative electrode core having a mixture layer-formed region where the negative electrode active material mixture layer is formed on each surface, and a negative electrode core-exposed portion where the negative electrode active material mixture layer is formed on neither of the surfaces,
• the negative electrode core-exposed portion being wound at one end portion of the wound electrode body in a winding axis direction,
• a current collector being connected by welding to an outer surface of the wound negative electrode core-exposed portion,
• the method comprising:
• a step of forming the wound negative electrode core-exposed portion at one end portion in the winding axis direction to prepare the wound electrode body such that an outer surface of the wound negative electrode core-exposed portion consists of the first surface, and an inner surface of the wound negative electrode core-exposed portion consists of the second surface;
• a step of placing the current collector on the outer surface of the wound negative electrode core-exposed portion and resistance-welding the current collector to the wound negative electrode core-exposed portion;
• and
• a step of enclosing the wound electrode body in a prismatic outer case comprising a prismatic outer body and a sealing plate,
• wherein the outer surface of the negative electrode core-exposed portion has a ten-point mean roughness Rz of 0.5 μm to 0.3 μm, and
• wherein a value obtained by subtracting the ten-point mean roughness Rz of the outer surface from a ten-point mean roughness Rz of the inner surface of the wound negative electrode core-exposed portion is 0.6 μm or more.