A positive electrode plate includes a positive electrode current collector, a positive electrode film layer arranged on at least one surface of the positive electrode current collector, and a conductive undercoat layer positioned between the positive electrode current collector and the positive electrode film layer. The positive electrode film layer includes a positive electrode active material including an inner core and a shell coating the inner core. The shell includes a first coating layer coating the inner core, a second coating layer coating the first coating layer, and a third coating layer coating the second coating layer. The conductive undercoat layer includes a polymer, an aqueous binder, and a conductive agent.