Transport Processes in a Li-ion Cell during an Internal Short-Circuit

Abstract

Internal short-circuit in a lithium-ion cell causes an abrupt increase in cell temperature and triggers subsequent thermal runaway. In this work, we present a detailed electrochemical-thermal model to investigate the physical behavior during an internal short-circuit. Simulations at wide range of heat transfer coefficients and short-circuit resistances are conducted to illustrate electrochemical and thermal behavior under a wide range of conditions. The Joule heating at the shorted region promotes electrochemical reactions nearby, causing in-plane non-uniformity of electrolyte and active material transport. Furthermore, it is found that diffusion in solid active materials plays a significant role at very high shorting currents (∼20 C), as electrochemical reactions rate are being controlled progressively more by availability of Li+ at the interface, due to limitations in diffusion through the active material with increasing discharge rates. This diffusion limitation causes a drop in available energy, and subsequently a decrease in cell equilibrium potential and the heat generation rate at the location of the short. On the other hand, rapid depletion of lithium concentration in the electrolyte and accumulation on the electrode surface results in highly non-uniform transport properties resulting in higher heat generation rates. Hence, the heating regime shifts from “local heating” to “global heating”. Based on the findings, important design parameters for battery safety are discussed.

Effect of High-Rate Cycle Aging and Over-Discharge on NCM811 (LiNi0.8Co0.1Mn0.1O2) Batteries

“…The increase in discharge temperature was attributed to the electrolyte and SEI decomposition [16,38]. After 120 cycles, the battery temperature was 40 • C. The battery was observed to exhibit severe thermal behavior once a new voltage plateau appeared; this was attributable to the generation and aggravation of micro-short circuits in the battery [14,40,41]. By the end of the 130th cycle, the temperature was increasing at a rate of 3.94 • C /min, and the voltage had dropped to 1 V. Additionally, the maximum temperature of the battery was 54.5 • C, but no dangerous thermal behavior was observed.…”

“…In addition, they found that the average strength of Li decreased by 13%, and that the half-peak width of Li distribution increased by 2%, suggesting the increased randomness of the lithium distribution, which reduced the utilization rate of active lithium. Kim [14] found that the large current near the short-circuit point generated a large amount of Joule heat, causing the temperature to rapidly increase. The voltage rapidly declined and slowly recovered, suggesting the occurrence of a recoverable micro short-circuit.…”

Risk evaluation of internal short circuit for lithium‐ion battery based on an active protection method

“…10,11 Also, the electrochemical-thermal coupled model is built to study the electrochemical and thermal behavior during an ISC process. 12 A structural design was produced to prevent thermal runaway propagation of cells with the aid of an electrochemical-thermal coupled model built by Tang. 13 More, electro-thermal coupled model is also widely used.…”

“…With the help of the electrochemical‐thermal coupled model, lithium‐ion transport and local overpotential can be calculated 10,11 . Also, the electrochemical‐thermal coupled model is built to study the electrochemical and thermal behavior during an ISC process 12 . A structural design was produced to prevent thermal runaway propagation of cells with the aid of an electrochemical‐thermal coupled model built by Tang 13 .…”

Simulation of Impedance Changes with Aging in Lithium Titanate-based Cells Using Physics-Based Dimensionless Modeling

“…16,17 These models have been mostly used in time-domain form for understanding battery performance, reliability, and safety. [18][19][20] However, use of these models requires tracking a large number of parameters related to phenomena such as electrochemical reaction rates, species conservation and charge conservation, in solid and electrolyte phase.…”