Active balancing circuit for Lithium-ion battery modules

2017 ELE Engineering Design Project (DX03)

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Faculty Lab Coordinator

David Xu

Topic Category

Power / Controls

Preamble

Active balancing for battery module is a leading technology in industry. which significantly improve the life of the battery cells. The integration of internal impedance measurement with the active balancing circuit can be used to determine the status of the battery cell, including SOC. The project is to design and implement a high efficiency active balancing circuit which is connected to the 12-cell lithium-ion battery module. The internal impedance of the battery cells are measured and displayed.

Objective

The objective of the project is to design an active balancing circuit for the 12-cell battery module. The impedance measurement of each cell is implemented in the active balancing control circuit.

Partial Specifications

The specification of the circuit is:
1) Maximum balancing current: 2A
2) The efficiency of the balancing circuit >80%
3) Internal impedance measurement: 5% accuracy

Suggested Approach

The group should study the exiting active balancing technology. The group is expected to propose a solution based on the survey results. In this project, three parts are included. 1) A battery measurement system to determine the balancing algorithm; 2) A DC/DC converter to extract one cell energy and dump to the other cells. 3) A switching matrix or other solution to connect the multiple cells to the DC/DC converter

Group Responsibilities

The group should be responsible for the project management, project demo and report.

Student A Responsibilities

Student A should design a battery measurement system and determine the balancing algorithm.

Student B Responsibilities

Student B should design a DC/DC converter or multiple DC/DC converter to extract one cell energy and dump to other cells.

Student C Responsibilities

Student C should design the switching matrix for the DC/DC converter to allow the energy from one cell to the others. The control of the DC/DC converter is the responsibility of the student. The topology finalized may use multiple DC/DC converters, the student C should be responsible for the controller of the DC/DC converters.

Course Co-requisites

ELE654