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​© 2020 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works., For lithium-ion batteries, active balancing can bring advantages compared to passive balancing in terms of lifetime and available capacity. Most known balancing techniques suffer from a low efficiency or high complexity and cost. This paper proposes a new technical solution based on a non-isolated DC/DC converter and a low-speed switching matrix to overcome efficiency and power limitations of present balancing methods. The proposed circuit allows balancing current paths which are not possible with previous methods and results in balancing efficiencies of over 90%. The performance comparison is based on batch numerical simulations using calculated and measured efficiency values. The simulation results are compared to the approved active balancing method cell-to-cell and to passive balancing. A study case with eight randomly distributed battery cells shows an improvement in overall balancing efficiency of up to 47.4% and a reduction in balancing time of up to 36.9%. The available capacity increases from 97.2% in a passively balanced system to 99.7% for the new method. A hardware prototype was set up to demonstrate the working principle and to verify the numerical simulations.

​© 2020 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works., For lithium-ion batteries, active balancing can bring advantages compared to passive balancing in terms of lifetime and available capacity. Most known balancing techniques suffer from a low efficiency or high complexity and cost. This paper proposes a new technical solution based on a non-isolated DC/DC converter and a low-speed switching matrix to overcome efficiency and power limitations of present balancing methods. The proposed circuit allows balancing current paths which are not possible with previous methods and results in balancing efficiencies of over 90%. The performance comparison is based on batch numerical simulations using calculated and measured efficiency values. The simulation results are compared to the approved active balancing method cell-to-cell and to passive balancing. A study case with eight randomly distributed battery cells shows an improvement in overall balancing efficiency of up to 47.4% and a reduction in balancing time of up to 36.9%. The available capacity increases from 97.2% in a passively balanced system to 99.7% for the new method. A hardware prototype was set up to demonstrate the working principle and to verify the numerical simulations.