By 2030 the sales of electric vehicles (EV) are set to increase 6 to 30 folds compared to the levels of 2019 thereby leading to an increase of discarded EV batteries. This creates a challenge to sustainably handle the waste by repurpose and recycling the EV batteries. In this paper, a method to analyze the usage of EV batteries throughout their life cycle in light of their contributions to a circular economy is proposed. The study is divided into two stages which are modelled with mixed-integer linear optimization. Stage 1 considers the optimal charging strategy for an EV and stage 2 represents the second-life of the EV battery as stationary energy storage in a residential building. Six scenarios were created for both stages; stage 1 includes smart charging and/or Vehicle to Grid (V2G) and stage 2 adds demand side management and/or PV self-consumption maximization to stage 1. A sensitivity analysis is performed to assess the impact of electricity prices. The results are analysed to assess the operational lifetime and economic savings for an EV owner. The results show that using second-life batteries in a residentail building can extend the lifetime of an EV battery by 3-5 years while allowing savings above 23%.