The fire hazard of lithium-ion batteries has influenced the development of more efficient and safer battery technology for energy storage systems (ESSs). A flowless zinc-bromine battery (FL-ZBB), one of the simplest versions of redox batteries, offers a possibility of a cost-effective and nonflammable ESS. However, toward the development of a practical battery, many critical issues should be addressed. In this contribution, we review the current FL-ZBB technologies and provide an assessment of them from a battery design perspective. The key cell design parameters and their influence on battery specifications are described. The challenges related to materials and cell structure are also discussed to motivate future research.