Thermal runaway (TR) initiation and propagation tests are essential for evaluating the safety of lithium-ion batteries (LIBs). However, differences among existing standards in application scenarios, test levels, initiation methods, boundary conditions, and acceptance criteria hinder direct comparison and cross-level transfer of safety evidence. This study reviews representative standards and experimental research concerning road vehicles, industrial batteries, stationary energy storage, and railway transportation. External heating, nail penetration, overcharge, built-in devices, and induction heating are compared in terms of target failures, energy input, structural disturbance, and source-term characterization. The analysis shows that TR initiation methods, together with cell chemistry, state of charge, capacity, and format, determine thermal, gaseous, and ejecta source terms. Cell spacing, electrical connections, thermal management, mechanical constraints, and enclosure ventilation and pressure relief further govern propagation pathways and system-level consequences. Accordingly, a multilevel evidence chain is proposed, encompassing target-failure definition, cell-level initiation-method qualification, module- or representative-propagation-unit validation, pack/system-level consequence assessment, and product-change review. A six-risk-domain equivalence-assessment method is also established to address source terms, topology, thermal pathways, protection, enclosure boundaries, and personnel exposure. The framework provides a traceable basis for interpreting cross-standard results, validating large-scale LIB systems hierarchically, and inheriting safety evidence following product changes.

Accurate prediction of external short-circuit (ESC) current is important for battery safety analysis and protection design, but conventional equivalent circuit models have difficulty reproducing the strongly nonlinear current evolution under ESC conditions. This study proposes a reaction-process-corrected second-order RC model for ESC current prediction, based on ESC experiments on a 37 Ah commercial NCM pouch cell at different initial SOCs. The ESC process is described by three successive stages: bottleneck control, concentration-difference control, and separator pore closure. To represent the transport-related resistance deviation during this process, an additional correction resistance R_x and a queued-charge descriptor Q are introduced into the equivalent circuit framework. A segmented closed-loop simulation strategy is then developed to update R_x and predict the ESC current. Using the 50% SOC case as an unseen validation case, the proposed model captures the main nonlinear characteristics of ESC current, including rapid initial decay, secondary rebound, and subsequent attenuation. The proposed framework improves the physical interpretability of equivalent-circuit-based ESC simulation while retaining engineering simplicity, providing a practical approach for safety-boundary assessment and protection-oriented battery system design.