<div>Batteries are widely applied to the energy storage and power supply in
portable electronics, transportation, power systems, communication
networks, etc. They are particularly demanded in the emerging
technologies of vehicle electrification and renewable energy integration
for a green and sustainable society. To meet various voltage, power, and
energy requirements in large-scale applications, multiple battery cells
have to be connected in series and/or parallel. While battery technology
has advanced significantly</div>


<div>in the past decade, existing battery management systems (BMSs) mainly
focus on state monitoring and control of battery systems packed in fixed
configurations. In fixed configurations, though, the battery system
performance is in principle limited by the weakest cells, which can
leave large parts severely underutilized. Allowing dynamic
reconfiguration of battery cells, on the other hand, allows individual
and flexible manipulation of the battery system at cell, module, and
pack levels, which may open up a new</div>


<div>paradigm for battery management. Following this trend, this paper
provides an overview of next-generation BMSs featuring dynamic
reconfiguration. Motivated by numerous potential benefits of
reconfigurable battery systems (RBSs), the hardware designs, management
principles, and optimization algorithms for RBSs are sequentially and
systematically discussed. Theoretical and practical challenges during
the design and implementation of RBSs are highlighted in the end to
stimulate future research and development.</div>