Thermal swelling and dimension-changing properties of the LiB (Lithium-ion battery) cell during the cycle (charging/discharging) and aging are well-known LiB's intrinsic characteristics. These inherent properties are caused by expansion/contraction of electrode materials due to lithium-ion intercalation, irreversible reaction deposits changing/increasing the volume, and the cell internal pressure changes by decomposition and gas generation. The cell designer's fundamental phenomena should be fully understood and implicated in the cell design and manufacturing process. As the LiB energy density increases, the safety zone/concept of a cell model considering LiB's natural phenomena is getting diminished and minimized.This paper analyzed the effect of the thermal swelling and dimension-changing properties of LiB cell on cell safety and studied the cell safety mechanism related to the cell design, considering the thermal swelling and dimension-changing properties of LiB cell. We used the electrode alignment and overhang of the electrode assembly (the gaps between the end of the separator and the end of the anode, and between the end of the anode and end of the cathode). Some cell models increased their energy density by sacrificing their safety zone, minimizing the gaps among separator – anode - cathode.We analyzed the relationship between the electrode alignment and overhang of the electrode assembly and the battery safety. We measured the electrode alignment and gaps among separator-anode-cathode with the microscope measurement technology and applied the electrical, thermal, and mechanical trigger factors to the cell models.Experimental results identified that the status of the electrode alignment and gaps among separator-anode-cathode effect to the cell safety for all the tests of the electrical, thermal, and mechanical trigger factors. We develop and propose a cell safety mechanism from the relationship between the electrode alignment and gaps among separator-anode-cathode and the cell safety. Figure 1