What is energy storage system architecture?

2025-06-16

The energy storage system architecture refers to the way in which each component is built into a complete energy storage system. To use an inappropriate analogy, for example, building a house is made up of bricks, floor slabs, stairs, windows, etc., but houses with different designs have different appearances, internal spaces, and usage functions, which means that different construction methods are used. Energy storage systems have four forms according to different architectures: string, centralized, distributed, and modular. Bonada will introduce them one by one below.

1. String energy storage

(1) String energy storage system structure

String energy storage adopts a modular design and consists of multiple smaller capacity energy storage units. Each energy storage unit is equipped with an independent battery management system (BMS) and power storage converter (PCS) that can be independently controlled and managed. This design makes the system highly flexible and scalable. Just like we can freely combine building blocks according to needs to build buildings of different shapes and sizes, string energy storage systems can also flexibly configure capacity according to actual needs, and can easily adapt to applications from small-scale household energy storage to large-scale industrial and commercial energy storage applications.

(2) Advantages of string energy storage

Advantage 1: High flexibility. It can flexibly configure and expand the system according to the actual power demand and site conditions. For example, in some small commercial places, the initial power load is small. As the business develops, the power demand increases. The string energy storage system can easily add energy storage units to achieve capacity expansion.

Advantage 2: High safety. Since each battery cluster controls the charge and discharge separately, the circulation phenomenon caused by the inconsistent discharge depth between different battery clusters is avoided, which effectively reduces the risk of battery overheating and fire. At the same time, the efficient thermal management system adopted can ensure good temperature uniformity between batteries, further extending the service life of the battery.

Advantage 3: Easy to transport and install. Its single cabinet is small in size and light in weight, which is convenient for transportation and on-site installation. It is particularly suitable for application scenarios with complex terrain or multi-point distribution. For example, in some distributed energy projects in mountainous or remote areas, string energy storage can easily cope with complex terrain conditions and achieve rapid installation and deployment.

(3) Application scenarios of string energy storage

String energy storage has a wide range of applications in many fields. On the industrial and commercial user side: it can help enterprises achieve peak load shifting and valley load shifting, and reduce electricity costs; in the field of shared energy storage: the flexibility and scalability of string energy storage enables it to better meet the needs of different users; in terms of new energy distribution and storage: string energy storage can effectively solve the intermittent and volatile problems of renewable energy generation and improve the grid's ability to absorb renewable energy.

2. Centralized energy storage

(1) Centralized energy storage system structure

Centralized energy storage usually adopts a container-type assembly method, with large capacity and volume for a single device. Its system structure is that Pack batteries are connected in series to form a battery cluster, and multiple battery clusters are connected in parallel on the DC side, and then merged into an energy storage inverter to convert into AC power, which is then connected to the grid after being stepped up by a transformer. This structure is like converging many small tributaries into a large river.

(2) Advantages and disadvantages of centralized energy storage

Advantages: The control logic is simple. Since the battery packs are directly connected in series to form a battery cluster, and then connected in parallel to a large PCS on the DC side, this structure makes the control system relatively simple and easy to manage and maintain. At the same time, the initial cost is low. Due to its simple structure and the ability to achieve large-scale procurement and centralized management, the cost of initial construction and operation and maintenance can be reduced.

Disadvantages: The barrel effect is obvious. All battery modules are connected in parallel. The overall life of the system depends on the battery module with the worst performance. There are inconsistencies in the discharge depth between different battery clusters, which leads to circulation, which in turn affects the charging and discharging efficiency and may cause safety risks. In addition, the operation and maintenance are complex. Once a failure occurs, professional personnel are usually required to be on-site for debugging and maintenance, which increases downtime and operation and maintenance costs.

3. Distributed energy storage

(1) Distributed energy storage structure

Distributed energy storage is to install energy storage systems in a decentralized manner at the power consumption end or the power grid side to balance the difference between energy supply and demand and improve the stability of the power grid.

(2) Characteristics of distributed energy storage

Distributed energy storage has significant flexibility and can be flexibly configured according to demand to increase or decrease energy storage capacity. It is sustainable and can achieve more efficient energy utilization by combining with renewable energy. With the ability to reduce grid pressure, distributed energy storage systems can support the grid during peak hours and reduce grid pressure, just like during peak traffic hours, numerous small roads can disperse traffic flow on the main roads. It can also improve the quality of electricity consumption and provide users with a more stable and reliable power supply by eliminating frequency deviations and reducing voltage fluctuations.

4. Modular energy storage

(1) Characteristics of modular energy storage

As the name suggests, modular energy storage adopts advanced modular design concepts to decompose the energy storage system into multiple standardized modules. These modules have a standardized structure that is easy to assemble and disassemble quickly. Each module contains components such as batteries, BMS, PCS, etc., just like a small energy storage system with independent functions. Users can flexibly select photovoltaic charging modules, grid-connected and off-grid switching modules, power frequency transformers and other components according to actual needs. This design enables the system to customize the structure of the system integrated cabinet, air ducts and communication protocols of BMS and EMS according to needs and the customer's own PACK, truly realizing personalized customization.

(2) Exploration of modular energy storage applications

Modular energy storage has broad application prospects in many fields. In the scenario of solar storage and charging, it can be combined with photovoltaic power generation and charging facilities to achieve efficient utilization and optimal configuration of energy. Modular energy storage also plays an important role in energy storage applications at the power grid and power station level. In the energy storage application of base stations, modular energy storage systems can provide stable power supply for base stations and solve the problem of power supply difficulties for base stations in remote areas.

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