In this paper, large-scale energy storage system(ESS) is taken as the research object to conduct study of business models on the participation of ESS in electricity spot market with liberalization. First, based on the typical market clearing mechanism at home and abroad, the clearing method, clearing calculation process and so on in day-ahead market and real-time balance market are analyzed, and a joint clearing mechanism suitable for large-scale ESS to participate in the spot market is proposed, including bidding method, billing method and clearing method, etc. Then, in order to fully explore the market value and other added value of large-scale ESS, to enhance cluster effect and to solve the problem of idle ESS capacity, business models suitable for large-scale ESS to participate in the spot market are proposed, including independent (single investment entity, single service model), alliance (diversified investment entities, single service model), and shared (diversified investment entities, diversified service models) models. The game relationship in the market transaction chain is analyzed, of which the electric energy value, the ancillary service value, and other added value are quantified. On this basis, a bilevel clearing model paradigm for ESS to participate in the spot joint market of different business models is constructed based on the master-slave game. In the upper-level model, large-scale ESS is the leader to participate in market competition with the goal of maximizing profits, while the dispatching and trading center in the lower-level model are followers to jointly clear the market with the goal of maximizing social welfare. Finally, the validity and feasibility of the proposed business models are verified by taking typical transaction scenarios as examples based on the improved IEEE30 node system.
