The quasi-biennial oscillation (QBO) is the strongest mode of variability in the tropical stratosphere and plays an important role in stratospheric dynamics and chemistry. The QBO is notably deficient in many climate models, including the Energy Exascale Earth System Model (E3SM) developed by the US Department of Energy. In this work, we utilize vertical grid refinement to reduce the lower stratospheric grid spacing from roughly 1 km to 500 m to facilitate more realistic synoptic wave activity in lower stratosphere in E3SM version 2. The refinement results in a simulated QBO with a reasonable amplitude and easterly-westerly transition, but still has a longer period than observed, slower easterly downward propagation speed, and shallower vertical depth. Similar refinement in the multi-scale modeling framework (MMF) configuration of E3SM yields similar improvements. By analyzing the forcing contributions from different wave types, we find that most of the QBO forcing still comes from parameterized gravity wave drag from convection. The improved QBO forcing contributions from resolved waves, especially equatorial Kelvin waves can be attributed to the grid refinement.