All-solid-state batteries (ASSBs) emerge as a promising next-generation power battery technology due to their ability to eliminate flammable organic components in conventional liquid lithium-ion batteries via introducing solid electrolytes. This innovation significantly enhances the safety window of the battery and holds a potential to further increase the energy density of the battery when combined with high-energy electrode systems. Consequently, ASSBs are regarded as a major technological route for next-generation energy storage devices.While liquid lithium-ion batteries are developed for years, establishing a well-developed and multi-tiered testing and evaluation system (i.e., basic electrode material tests, interface behavior analysis, single-cell performance assessments, system integration/management for performance, lifespan, and safety evaluation), ASSBs differ significantly in their technological characteristics. These differences span ion transport mechanisms, interface properties, thermal stability, and environmental adaptability. Furthermore, the introduction of new materials, processes, and structures for ASSBs presents some challenges for the existing testing and evaluation systems.The existing solid-state battery technology is still in a phase of rapid development, and some technical issues and challenges for testing and evaluation are expected to emerge throughout this process. It is thus necessary to simultaneously advance new testing technologies such as in-situ detection, intelligent simulation, and data-driven approaches, alongside the establishment of conventional testing and evaluation systems. These advancements enable highly efficient testing and evaluation throughout the entire lifecycle of solid-state battery products, from design to application and post-decommissioning processing.In terms of in-situ detection, it is critical to develop real-time observation techniques with high temporal and spatial resolution to capture key dynamic processes such as interface evolution, lithium dendrite growth, and side reactions during battery operation. These techniques will provide multi-scale and multi-dimensional dynamic data. Intelligent simulation involves coupling multiphysics models (i.e., electrochemical-mechanical-thermal models) with high-performance computing to analyze and predict the battery performance and failure mechanisms under complex operating conditions. Data-driven technologies offer an innovative direction for testing and evaluation systems by leveraging big data analytics and machine learning algorithms. These technologies will enable precise predictions of unknown parameters and enhance the flexibility and adaptability of testing methods.With the integration of these emerging testing technologies, the development of ASSB technology will gain new momentum and drive breakthroughs in the field. To address the challenges for ASSBs, novel testing methodologies should be developed, including key material analysis, in-situ characterization, comprehensive battery performance evaluation, failure and hazard analysis, and simulation techniques. This review explores the fundamental technological differences between ASSBs and liquid lithium-ion batteries and systematically discusses the key ideas for establishing a testing and evaluation system tailored to ASSBs. The review also examines some key issues and technical challenges related to testing at the material, cell, and system levels. It proposes a framework for building a comprehensive testing and evaluation system specifically suited to the characteristics of ASSBs via analyzing the current state of testing technology development. The aim is to provide a theoretical foundation and practical guidance for the technological research and industrial application of all-solid-state batteries.Summary and prospectsThis review focuses on the status and challenges of testing and evaluation technologies for all-solid-state batteries (ASSBs). As ASSBs are considered as a promising alternative to conventional lithium-ion batteries due to their enhanced safety and potential for higher energy density, understanding and addressing the unique testing challenges they pose is critical. The review systematically represents the novel characteristics of ASSBs, particularly in terms of ion transport mechanisms, interfacial stability, thermal safety, and environmental adaptability. These characteristics significantly differ from those of liquid-based lithium-ion batteries, presenting new challenges in evaluating their performance, reliability and safety.The review also analyzes the limitations of existing testing and evaluation systems, which are primarily designed for liquid lithium-ion batteries, and highlights a need for new approaches to meet the specific demands of ASSBs. The discussion emphasizes the necessity of developing a comprehensive testing framework that spans all levels, from materials and interfaces to battery cells, systems, and even vehicles. This comprehensive approach is essential to properly assess ASSBs in terms of their performance, lifecycle, and safety under different environmental conditions.Furthermore, the review identifies some key challenges arising in the evolution of testing technologies, i.e., the need for more accurate in-situ analysis techniques, the integration of intelligent simulation tools, and the incorporation of data-driven approaches. To address these challenges, the review proposes directions for advancing testing methodologies, such as developing high-resolution, real-time in-situ observation tools to capture dynamic processes, utilizing multi-physics simulations to predict performance under complex conditions, and leveraging machine learning for data analysis and prediction of battery behavior. These advancements can integrate cutting-edge techniques into the testing and evaluation processes, facilitating the transition of ASSBs from laboratory research to commercial applications, and ultimately enabling the broader adoption of solid-state battery technology in various industries.