  This paper presents a novel modular, reconfigurable battery energy storage
system. The proposed design is characterized by a tight integration of
reconfigurable power switches and DC/DC converters. This characteristic enables
isolation of faulty cells from the system and allows fine power control for
individual cells toward optimal system-level performance. An optimal power
management approach is developed to extensively exploit the merits of the
proposed design. Based on receding-horizon convex optimization, this approach
aims to minimize the total power losses in charging/discharging while
allocating the power in line with each cell's condition to achieve
state-of-charge (SoC) and temperature balancing. By appropriate design, the
approach manages to regulate the power of a cell across its full SoC range and
guarantees the feasibility of the optimization problem. We perform extensive
simulations and further develop a lab-scale prototype to validate the proposed
system design and power management approach.
