What are the differences between energy storage PCS and a photovoltaic inverter?

I. Different Core Positioning

The core task of a PV inverter is "DC to AC conversion". The electricity generated by PV panels is DC, which cannot be directly connected to household circuits or the power grid. The inverter acts like a "converter", precisely converting the DC power into AC power that meets grid standards. This AC power is then either directly supplied to the load or fully connected to the grid. The entire process is "one-way transmission": PV panel → inverter → grid/load.

The core task of a power storage PCS is "two-way conversion + energy management". It not only converts the DC power from the battery to AC power (discharging), like an inverter, but also converts excess AC power from the grid or PV panels back to DC power (charging and storing in the battery). It's equivalent to a "two-way converter + intelligent dispatcher", deciding whether to "store", "discharge", or "shut down" based on grid demand and battery status. For example, it charges when grid electricity prices are low and discharges when prices are high, achieving peak shaving and valley filling.

II. Different Working Principles

PV inverters only have one working path: "DC → AC". The key technology is "MPPT (Maximum Power Point Tracking)". Just like finding the "optimal operating state" for photovoltaic  panels, real-time tracking of the maximum solar power output allows the PV panels to generate more electricity, which is then efficiently converted into AC power for grid connection, eliminating the need to consider "electricity storage".

Energy storage PCS (Power Conversion System) has two paths: "AC → DC" (charging) and "DC → AC" (discharging). The core is "bidirectional conversion control" and "battery collaboration". During charging, excess AC power from the grid/PV system is converted into DC power that the battery can store. During discharging, the DC power from the battery is converted back into AC power for use. Simultaneously, it works with the Battery Management System (BMS) to monitor battery voltage and temperature, preventing overcharging and over-discharging and ensuring safety.

III. Different Application Scenarios

PV inverters are needed wherever there are PV panels, such as centralized PV power plants, distributed residential PV systems, and PV greenhouses. The core is to "make PV electricity usable and connect to the grid".

Energy storage PCS must be used in conjunction with energy storage batteries, such as in residential energy storage systems, commercial and industrial energy storage power stations, grid-side energy storage projects, and energy storage for new energy vehicle charging piles. The core function is to "solve the problems of unstable new energy power generation and peak-valley differences in electricity consumption". For example, if photovoltaic power generation is high during the day and low at night, the PCS can store the excess electricity generated during the day and release it at night, avoiding waste.

IV. Different Key Parameters

When selecting a photovoltaic inverter, focus on "conversion efficiency" (how much is wasted during power conversion), "MPPT (number of MPPT channels)" (how many photovoltaic panels can be connected simultaneously), and "grid compatibility" (whether it can match the local power grid).

When selecting an energy storage PCS, focus on "bidirectional conversion efficiency" (total losses during charging and discharging), "charge-discharge rate" (battery charging and discharging speed), "battery compatibility" (whether it can be adapted to different brands of lithium batteries), and "response speed" (whether it can quickly charge and discharge when the grid needs it).

Simply put, a photovoltaic inverter is a "converter at the generation end", only responsible for "converting electricity to the grid"; an energy storage PCS is an "energy storage dispatcher", responsible for "storing, discharging, and regulating electricity". The two are not substitutes, but complements. In new energy systems, photovoltaic inverters solve the problem of "power generation", while energy storage PCS solves the problem of "energy storage and power consumption optimization". Only by using them together can the stable and efficient utilization of new energy be achieved.