Modular and Reconfigurable Battery Energy Storage System

University of Kansas researchers have developed a battery energy storage system with an advanced circuit structure including both switches and power electronic converters. Lithium-ion battery energy storage systems (BESSs) have played a key role in enabling electrified transportation, smart and micro grids, adoption of renewable energy, and space systems. BESS operation requires high safety, reliability, and fault tolerance especially in safety-critical applications. However, conventional BESSs often struggle to meet this need. With a fixed, hard-wired connection between constituent cells or units, the failure of just one cell will disrupt the operation of the whole BESS and even damage the BESS in extreme cases of fire and explosion. Further, the fixed connection will make the BESS vulnerable to heterogeneity or imbalance among the constituent cells, compromising the overall performance. The KU BESS design aims to solve these issues.

Lithium-ion batteries have established themselves as a dominant energy storage technology in numerous applications across different industry sectors. Compared to other types of batteries, their merits are high energy density, low self-discharge characteristics, and lower maintenance requirements. Large-scale lithium-ion battery systems have found increasing use across many sectors and present high safety needs.

BESSs have been widely used in various applications, most notably including electrical vehicles, electric aircraft, renewable energy integration, smart grid, power tools, and portable electronic devices.

How It Works: This design aims to solve conventional BESS issues by introducing an advanced circuit structure incorporating battery cells with power electronic converters, and power switches that can change the connection configuration among the battery cells. It is capable of bypassing faulty cells without interrupting the operation of the entire system, while ensuring consistent voltage or power supply and maintaining a balanced use of the remaining cells. The resulting system is a reconfigurable, modular BESS.

Why It Is Better: Not only does the proposed design address the mentioned problems with the conventional BESSs, but it also unveils unique advantages further improving the performance of the BESS in terms of reliability and safety.