BMS for Li-ion battery modules using active balancing circuit

2021 ELE Engineering Design Project (DX01)

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Faculty Lab Coordinator

David Xu

Topic Category

Consumer Products/Applications

Preamble

In modern energy system, the battery cells are packed together to form a module. Usually 12~18 cells are connected in series to form a module. The battery management system (BMS) for each module is connected to the cells to determine the status of each cell, including the state-of-charge (SOC), cell temperature, cell voltage as well as other parameters. BMS also measures the current of the module to determine the pack SOC. In case of non-balanced cells, active balancing circuit will move the energy from the cell with higher SOC to the others. The project is to design a BMS system with active balancing circuit for multi-cell Lithium-ion battery module including module protection.

Objective

The objective of this project is to design a BMS system for 12-cell lithium-ion battery module. The BMS system should be able to determine the status of each cell, balancing the cell and protect the cells from faults.

Partial Specifications

The requirements for the BMS are:
1) The model should integrate a 12-cell series connected pack at 50Ah.
2) Develop an algorithm to determine the SOC of pack.
3) Protect the module from over charging/discharging.
4) Balance the cell capacity using active balancing circuit.

Suggested Approach

1)) The group should study the model of Li-ion battery with 12 cells in series connection. The charging and discharging characteristic should be investigated.
2) The group should determine the active balancing circuit and choose one for the design
3) Build a model to determine the pack SOC from measured current and voltage information.
4) The group should investigate the protection scheme of Lithium-ion battery system

Group Responsibilities

Group should be responsible for finalize the design, project report and demo

Student A Responsibilities

Student A is responsible for the active balancing circuit.

Student B Responsibilities

Student B is responsible for the control of the balancing circuit

Student C Responsibilities

Student C design the protection circuit and protection scheme of the battery management system

Student D Responsibilities

Student D develop the algorithm of the SOC calculation from measured voltage and current.

Course Co-requisites

ELE754

To ALL EDP Students

Due to COVID-19 pandemic, in the event University is not open for in-class/in-lab activities during the Winter term, your EDP topic specifications, requirements, implementations, and assessment methods will be adjusted by your FLCs at their discretion.