Automatic battery equalizers require no sensing circuits, which reduces their cost, size, and complexity. However, among existing methods, additional resistors or diodes are used in the balancing paths to ensure safe operation, which degrades the conversion efficiency and balancing speed. To overcome this problem, this article proposes an equalizer architecture based on the half-bridge LLC converter. The inherent current limitation characteristic of the proposed equalizer improves the balancing speed. High conversion efficiency is achieved due to the soft-switching operations of the switches. The circuit topology and working modes are presented first, then the features of voltage equalization, inherent current limitation, and soft-switching conditions are analyzed in detail. Finally, the proposed equalizer is validated by simulation and experiment.