Different types of BMS architectures: centralized, modular and distributed

At the moment when the new energy industry is booming, battery management system (BMS) is the core component of the battery system, and its architectural design plays a crucial role in the performance, safety and service life of the battery pack. Currently, BMS architectures are mainly divided into three types: centralized, modular and distributed. Each architecture has its own unique characteristics and applicable scenarios. The following will be discussed in detail.

Centralized BMS architecture

Definition and structure

A centralized BMS is to centralize all control and management functions in one main control unit, and usually one main control board monitors and manages the entire battery pack. The main control unit connects each battery cell through the acquisition line, collects voltage, temperature and other data, and performs balanced management and protection according to the preset control strategy.

Advantage 

• Simple structure and low cost: All functions are concentrated in one controller, the hardware design is simple, and the production cost is low. It is suitable for small and simple battery systems, such as power tools, smart homes, electric bicycles, etc.
• Easy to maintain and upgrade: only one main control unit is required, maintenance and upgrade is more convenient.
• Dataset, easy to analyze: All battery data is processed in one controller, making it easy to conduct unified analysis and decision-making.

Disadvantage

• Low reliability: The risk of single point failure is high. If the main control unit fails, the entire system may be shut down.
• Complex communication lines: There are many communication lines in centralized BMS, which are prone to interference and unstable signal transmission.
• Poor scalability: Not suitable for applications with large capacity or large-scale battery packs.

Distributed BMS architecture

Definition and structure

A distributed BMS distributes control and management functions into multiple controllers, each responsible for managing one or more battery cells. The main control unit is responsible for coordinating the operation of each slave control unit to form a distributed management architecture.

Advantage

• High reliability: Under a distributed structure, a controller failure will not affect the operation of the entire system, and the risk of single point failure is low. It is suitable for scenarios such as large electric vehicles, hybrid vehicles, fuel cell vehicles and large-scale energy storage systems that require high reliability requirements.
• Simple communication line: the communication load is distributed and has strong anti-interference ability.
• Good scalability: Suitable for large-capacity battery packs, the battery cells can be increased or decreased according to demand.

Disadvnatage

• Complex structure and high cost: Each battery cell requires independent monitoring and control modules, and the hardware and software design is complex and the cost is high.
• Maintenance and upgrade is difficult: In a distributed structure, the maintenance and upgrade of each controller requires higher technical support.
  Data is distributed and difficult to analyze: the data is distributed in multiple controllers, and a unified communication protocol and data processing algorithm are required.

Modular BMS architecture

Definition and structure

Modular BMS is a solution between centralized and distributed. It divides the battery pack into multiple modules, each with centralized management within, while modules with distributed architecture for communication and coordination.

Advantage

• High flexibility: The modular design can flexibly adjust the number and function of modules according to requirements, and is suitable for medium and large battery packs, especially scenarios where flexibility and scalability are required, such as hybrid vehicles, grid energy storage systems and smart grid applications.
• Strong scalability: supports the expansion of large-capacity battery packs while maintaining certain cost-effectiveness.
  Easy to maintain: Each module runs independently and can be handled separately during maintenance and upgrades without affecting the entire system.

Disadvantage

• The structure is relatively complex: modular BMS combines the characteristics of centralized and distributed, and the hardware and software design is relatively complex.
• Higher cost: Although the cost is lower than distributed BMS, it is still higher than centralized BMS.
  Communication coordination is difficult: communication and coordination between modules require efficient protocol support, otherwise it may affect system performance.

Comparison of three architectures

Summary and selection suggestions

When choosing a BMS architecture, users need to weigh the specific application scenarios and needs:

• Centralized BMS: Suitable for small, simple battery systems such as power tools, smart homes, electric bicycles and small energy storage systems, it is low-cost and easy to maintain.
• Distributed BMS: Suitable for large and complex battery systems, such as large electric vehicles, hybrid vehicles, fuel cell vehicles and large-scale energy storage systems, providing higher reliability and scalability, but with higher costs.
• Modular BMS: takes into account the advantages and disadvantages of centralized and distributed, and is suitable for medium and large battery packs that have a need for flexibility and scalability, such as hybrid vehicles, grid energy storage systems and smart grid applications.

In the future, with the continuous development of new energy technology, the architectural forms of BMS will also be more diversified to meet the needs of different scenarios.