A battery pack includes a battery housing and electrochemical cells disposed in the battery housing in a stacked configuration. Elastic members are disposed between adjacent cells of a cell stack. Each elastic members is formed as a plate (e.g., a single-thickness sheet) having a curved or wavy contour when seen in cross-section, and is configured to serve as a compression spring that provides a predetermined compression force to adjacent cells while accommodating cell growth during use. The elastic members may include surface features such as strategically shaped and/or located protrusions that are configured to permit compliance and can be tuned to address the requirements of a specific application and permit application of varying stiffness characteristics across a surface of a cell.