The growing demand and new fields of application compel battery manufacturers to higher product quality. As the battery separator is the main safety element of a battery cell, defect-free separators are a prerequisite for safe lithium-ion batteries. Hence, typical production defects have to be reliably detected by 100-percent inspection methods. For that reason, this paper presents the design of a non-destructive inspection approach for battery separator quality testing. Based on a requirements analysis the most appropriate test method is selected. Subsequently, a detailed implementation concept is derived and proven within a real production scenario.