Charging modes demand more from the power grid while battery swapping is more grid-friendly.
The boost in power and widespread adoption of charging stations has created bottlenecks for the distribution network. The increased power and quantity of charging stations have added greater pressure to the distribution grid, resulting in a series of grid-related issues that have hindered the large-scale implementation of 800V supercharging. Firstly, research from State Grid Economic and Technological Research Institute shows that electric vehicle (EV) charging peaks coincide with residential electricity consumption peaks by as much as 85%. The power increase and expansion of charging stations will further intensify the strain on the grid during periods of high electricity demand. The grid incurs additional costs to meet the short-duration, high-amplitude electricity demands during peak periods, resulting in increased idle costs and decreased equipment utilization during low-demand periods. Secondly, the high instantaneous power output during charging can cause voltage fluctuations, affecting the quality of power supply. If severe, voltage fluctuations can lead to distribution safety accidents. Voltage fluctuations caused by 800V supercharging are more severe compared to regular charging stations, potentially compromising the safety of the distribution grid. Thirdly, according to the White Paper on EV User Charging Behavior in China 2022 published by the China Electric Vehicle Charging Infrastructure Promotion Alliance and Nenglian ZhiDian, around 66% of the charging stations in China are privately owned, with 75% of new charging stations coming from private sources. This uneven distribution of charging stations increases the difficulty of managing and regulating the grid.
Limited power capacity in residential areas makes it challenging to exceed the maximum number of EV charging spaces. Many residential areas lack sufficient power capacity due to inadequate planning. As a result, they cannot provide an adequate number of charging spaces while maintaining the residents' normal daily activities. This problem ultimately stems from the fact that residential areas have a finite distribution capacity. Typically, the ratio of parking spaces to charging stations is 3:1, meaning that only about 30% of parking spaces in residential areas can accommodate charging stations. Once the overall penetration rate of new energy vehicles exceeds 30% (monthly sales penetration rate has already exceeded 30%), the problem of daily charging demand will come under great pressure. New energy vehicle owners may need to use commercial charging stations after work, posing significant challenges to the future user experience of electric vehicles and potentially impacting the growth in the number of new energy vehicles. The shortage of charging spaces is fundamentally rooted in the residential areas themselves. The high cost and difficulties associated with retrofitting greatly impede the widespread adoption of charging stations.
Battery swapping enables controlled charging and relieves grid load while assisting in peak shaving and frequency regulation. The high pressure on the grid caused by charging stations largely stems from the disorderly charging behavior of users. In contrast, battery swapping allows for controlled charging times and balanced power consumption. Battery swapping stations can respond to grid dispatching, charging batteries during low-load periods (such as nighttime), and directly providing fully charged batteries to residents during peak demand periods. This not only alleviates the pressure on the grid but also assists in peak shaving. According to NIO's announcement, as of August 2022, out of the 1,067 battery swapping stations nationwide, 575 participated in off-peak charging, accounting for nearly 60% of the stations. The proportion of electricity consumed during off-peak periods increased from 12% to 20%, resulting in a transfer of 4.1 million kilowatt-hours of high-peak electricity consumption within 30 days. The transformation from disorderly and uncontrolled charging to orderly and controllable charging, avoiding peak electricity consumption periods for residents, greatly alleviates the pressure on the grid. NIO's battery swapping stations have also participated in peak shaving for the Zhejiang power grid, becoming the first automaker in China to be connected to the National Grid's virtual power plant. In recent years, electricity consumption has surged in many parts of the country. According to statistics from the National Power Dispatch and Control Center, the highest electricity consumption in the national grid in 2022 reached 1.29 billion kilowatts, a year-on-year increase of 6.3%. The China Electricity Council predicts that the peak electricity demand in 2023 may exceed 1.37 billion kilowatts, demonstrating an increasing trend in electricity demand during peak periods. In this context, battery swapping stations, as virtual power plants, will play an increasingly prominent role in assisting peak shaving and frequency regulation.
Battery swapping stations with energy storage capabilities can assist in frequency regulation and safeguard the safe operation of the power system. Battery swapping stations can participate in frequency regulation by connecting to the grid dispatching center when there is a deviation in grid frequency, ensuring the safe operation of the power system. Taking NIO as an example, based on the battery allocation at its stations, each battery swapping station has an energy storage capacity of 600-700 kilowatt-hours, with around 13 batteries per station. Two to three batteries are reserved for customer swapping, while the remaining 10-11 batteries can be discharged to the grid for 5-10 minutes during idle periods to assist in grid adjustment. In 2022, NIO's 15 battery swapping stations in Hefei helped the Power Dispatch and Control Center reduce the load by 1.4 megawatts within one minute, with an increase of only about 5 minutes to the charging time for each battery, which had minimal impact on the normal battery swapping service for users.