## 1 Introduction  
With the rapid development of renewable energy (RE), its uncontrollability and volatility have caused a series of problems to the grid [1; 2; 3; 4]. Cooperation with controllable resources to enhance the controllability of RE has become a consensus [5; 6; 7]. Although the construction of an energy storage station (ESS) for RE can effectively improve the controllability of RE [8], the investment cost of an ESS limits its large-scale promotion and application. The batteries of electric vehicles (EVs) can be regarded as a large number of cheap energy storage devices which provides a new idea to solve the problem of the high investment cost of conventional ESS. However, the mechanism of unified charge-discharge management for a large number of decentralized EVs is complex and difficult to implement [9]. The battery swapping pattern realizes geographical decoupling between batteries and EVs. As a result, the EV battery switch station (BSS) could achieve multiple benefits with the help of battery to grid (B2G) technology [10]. In addition to providing EV users with battery-swapping services, the BSScan also serve as an ESS or controllable load [11]. Therefore, the cooperation between RE and BSS is feasible and effective. The collaboration could not only benefit the power grid, but also promote the development of the RE industry and EV industry. In [12], an economic dispatch model of the microgrid including the RE and BSS is established, and the economy of microgrid operation is improved through the cooperative optimization of the RE and BSS. The uncertainty of RE generation and battery-swapping demand is further considered in [13]. A stochastic optimization model of the microgrid including the RE and BSS is established based on the chance-constrained programming. In [14], a multi-objective cooperative optimizing model of the BSS and RE is established by fully considering the randomness. By adjusting the charging and discharging power of the BSS in coordination with the RE, the load fluctuation and network loss is reduced effectively, and the planning penetration of the RE is improved as well. However, these studies need the grid company as a coordinating body to coordinate and control a variety of dispatchable resources. Because of this, these studies are based on the interests of grid companies, while the interests of RE and BSS are not fully considered. In the interest of the RE and BSS, the integrated mode of them was proposed [15; 16; 17; 18; 19]. If built together with a wind turbine (WT) and photovoltaic (PV) generation unit, the BSS can use the RE to charge electric vehicle batteries directly, which can not only cut the charging cost, but also reduce the carbon emissions of electric vehicles. Reference [15] established a collaborative operation pattern, in which the EV batteries are charged by wind and photovoltaic energy in the BSS. The results showed that the collaborative operation pattern can not only promote the local absorption of the RE, but also help to reduce the peak and valley difference of power load in the power system. An energy exchange model of the PV-based BSS was proposed considering the battery swapping service and power distribution in [16]. [PERSON] et al. further researched the charging strategy of the PV-based BSS considering the self-consumption of PV energy in [17]. References [18; 19] suggested that wind farms and BSS should be combined into a joint system and operate as an independent enterprise in the power system. With a unified coordinated control of wind farms and BSS, the whole benefit of the joint system is maximized. The simulation results showed that this operation mode can achieve a win-win situation for wind farms and BSS. However, there is a prerequisite for the above research, that is, RE and BSS belong to the same investment subject or they have the will to form a joint system. With the development of the electricity market reform in China, the investors in the electricity market are becoming more and more diversified and complicated.