In-Depth Analysis of Photovoltaic (PV) Storage and Charging

Photovoltaic systems can be classified into grid-connected and standalone types. system. 

• Grid-connected systems consist of key components such as PV modules, support structures, cables, and grid-tie inverters. Their primary feature is feeding the generated electricity directly into the public grid.

• Standalone systems are based on these components but add energy storage batteries and charge/discharge controllers, enabling autonomous storage and utilization of electrical energy.

The fundamental difference between the two lies in the presence of energy storage devices.

During the energy conversion process:

1. The PV modules first convert solar energy into direct current (DC).
2. The inverter then transforms DC into alternating current (AC) that meets grid standards.

This energy conversion process is the core principle of photovoltaic power generation technology.

02 Energy storage system

Core role：

The core function of an energy storage system is to enable the temporal and spatial transfer of electrical energy, effectively addressing the mismatch between power generation and electricity consumption.

Technical analysis：

The working principle of an energy storage system can be vividly compared to a "giant power bank": it stores surplus electricity generated by photovoltaic systems in batteries and releases it during peak demand periods.

When photovoltaic generation exceeds immediate needs, the system switches to charging mode; when electricity demand increases or generation is insufficient, it switches to discharging mode, converting stored energy back into electrical power. This "low storage, high release" operation mode not only helps balance supply and demand (peak shaving and valley filling) but also allows participation in electricity market trading to profit from price differences between peak and off-peak periods.

Additionally, it can alleviate supply-demand conflicts on the user side, reduce investment in power generation equipment, improve utilization rates of electrical devices, and decrease transmission losses.

03 Charging system

Core role：

The core role of the charging system, as the terminal link of the integrated photovolatic, storage, and charging solution, is to achieve efficient distribution and intelligent scheduling of electrical energy.

Technical analysis：

Photovoltaic-storage type battery swap stations mainly operate based on the principles of grid-connected photovoltaic power systems. The solar energy converted by photovoltaic modules is stored in batteries via a photovoltaic charging controller and can also be transmitted to the grid through a grid-connected inverter. This allows part of the generated electricity to charge electric vehicles, while another part is inverted and fed into the grid. Additionally, the photovoltaic station can serve as a backup power source for highway service areas. When the system’s monitoring unit detects a grid failure and cannot supply power, it can quickly disconnect from the grid and immediately switch to inverter-based off-grid power supply. Once the grid issue is resolved, the system can revert to normal operation.