Abstract: Lithium-ion battery energy storage power stations (LIB ESS) are characterized by high DC-link voltage and high short-circuit current characteristics. DC-side short-circuit faults may lead to severe consequences including thermal runaway, fire hazards, or even explosion incidents. Focusing on the most critical pole-to-pole short-circuit fault in the DC side of LIB ESS, this study employs actual engineering cases to calculate short-circuit current values at different inter-pole fault locations. Based on the analysis, a corresponding DC-side protection device selection methodology is proposed, with detailed elaboration on protection coordination mechanisms including selective tripping and cascading protection schemes. The research provides practical guidance for engineering design of DC-side protection in BESS applications, with significant implications for enhancing system safety and reliability in utility-scale energy storage systems.