At present, there are two important architectures for lithium-ion battery pack bMS products, a centralized management system and a distributed management system. The aggregation type has lower cost, but the wiring harness is more complicated and has to correspond to the battery cells one by one. If it is connected incorrectly, there will be a risk of battery short-circuit and fire. The distributed wiring harness is relatively simple, but the cell management unit (CSC) still has to maintain a one-to-one correspondence with the battery cell (by setting the soft address or hard address on the CSC to deal with), which brings additional processing and maintenance Workload. And another point to note is that if you want to realize the active equalization function, the bMS of these two architectures need additional connections to complete the energy transfer. Not only that, but another problem that has to be dealt with is the switch matrix, which is how energy flows from the entire battery pack into any single cell. The method currently in use is through relays, which is simple to implement, but also brings problems with life and reliability. Because the relay is a mechanical and electronic component, there is a life limit and the risk of adhesion when switching. Another treatment method is to use electronic switches, MOSFETs, but it will increase the cost and complexity of the circuit.

From the point of view of function realization, all functions of bMS have no insurmountable technical threshold, but from the point of view of actual use, the difficulty of bMS products lies in the complicated wiring harness, one-to-one correspondence, and low high current active balance. Cost realization. Neither the aggregate management system nor the distributed management system can handle these problems well.

A start-up company proposed a third architecture, a building block architecture, which cleanly handled the bMS problem.

The system consists of three parts: UM (single module), controller and bus (2-wire system). The battery packs are divided into one or more groups according to the number of cells. Each battery cell is equipped with a UM module, which is a standard module without any soft and hard address settings. The module has 4 ports, 2 inputs and 2 outputs. The input is connected to the positive and negative poles of the battery, and the output is connected to each group of buses; the bus is a 2-wire system, which can transmit data and energy, and the active balance current can reach 10A; The controller is connected so that a system is formed. Just like building blocks, multiple systems can be connected through the CAN bus to build a larger-scale (100-string level) battery pack energy management system, and the building block architecture gets its name. The modules and buses that make up the system are all standard components, and only the controller will have corresponding settings based on the size of the system.

At first glance, this architecture is similar to the distributed architecture, and its UM is similar to the distributed CSC function; but its UM is more concise and flexible than CSC, without any address settings, that is to say, any 2 UMs Both can be replaced with each other, the processing and maintenance efficiency will be much higher, and the requirements for the operators are not so high. The bus has only two wires, but it unifies data transmission and energy transmission, and solves the problems of wiring harness and matrix switch. This third architecture of bMS has the potential to become the final architecture of bMS products.