**6. Conclusions**

The paper proposes a fast charging balancing circuit for LiFePO4 battery. The main concept is to give a fast voltage balancing strategy for each cell within a single battery string. In this study, a novel bi-directional forward converter is utilized and connected with the balancing bi-directional switches network to form a bi-directional battery balancing circuit.

The feature of the proposed scheme is to balance the maximum differential voltage between the odd-numbered battery and the even-numbered battery in the battery string directly. In order to verify the proposed structure, a fast battery charging circuit for a string with 8 pieces of cell (3.6 V/2.5 Ah for each cell) is implemented. In addition, the merit of this circuit can also avoid over charging situation during the balancing process.

Referred to the experimental and simulation results in previous section, a faster charging balancing circuit for a battery string is achieved. The advantage of this scheme also improves the precision of each cell after balancing procedure. The future research will keep improving the balancing algorithms for random cells in the battery string. Moreover, the proposed study can save more time during the balancing process. At present, industrial applications, electric vehicles batteries, and higher capacity batteries are always composed of many cells connected in series and parallel; therefore, the characteristics and aging phenomenon of each cell have to be concerned with care. In the near future, a battery managemen<sup>t</sup> system can be added for the proposed balancing circuit to obtain a high precision and faster battery equalizer for each cell.

**Author Contributions:** S.-T.W. and Y.-N.C. conceptualized and supervised the experiments of the research. S.-T.W. revised and modified the research data into paper format. Y.-N.C. provided the testing bench of the research. C.-Y.C. was in charge of software environment building up. Y.-T.C. was in charge of measurement, and data recording.

**Funding:** This research received no external funding.

**Conflicts of Interest:** The authors declare no conflict of interest.
