The integration of renewable energy sources into power systems necessitates the effective utilization of flexible resources such as energy storage systems and electric vehicles. These resources are vital for maintaining grid stability and reliability by balancing supply and demand and mitigating the variability of renewable energy. This paper addresses the challenge of accurately modeling and aggregating the regulation characteristics of flexible resources. We propose a novel de-translation approximation method that ensures compliance with the non-simultaneous charging and discharging constraint for each individual resource, a problem not adequately addressed in previous studies. By utilizing the inner approximation method based on homothet polytopes, we achieve an efficient aggregation of high-dimensional optimization problems. Numerical experiments validate the feasibility and effectiveness of the proposed method, demonstrating its potential to enhance the operational flexibility and reliability of power systems with high renewable energy penetration. This study contributes to the broader goal of achieving a sustainable energy transition through advanced modeling and aggregation techniques.