Review—Thermal Safety Management in Li-Ion Batteries: Current Issues and Perspectives

Rengaswamy Srinivasan,Thomas P Barrera,Judith A Jeevarajan,Bliss G Carkhuff,Shriram Santhanagopalan,Plamen A Demirev

doi:10.1149/1945-7111/abc0a5

Abstract

Approaches for thermal management of lithium-ion (Li-ion) batteries do not always keep pace with advances in energy storage and power delivering capabilities. Root-cause analysis and empirical evidence indicate that thermal runaway (TR) in cells and cell-to-cell thermal propagation are due to adverse changes in physical and chemical characteristics internal to the cell. However, industry widely uses battery management systems (BMS) originally designed for aqueous-based batteries to manage Li-ion batteries. Even the “best” BMS that monitor both voltage and outside-surface temperature of each cell are not capable of preventing TR or TR propagation, because voltage and surface-mounted temperature sensors do not track fast-emerging adverse events inside a cell. Most BMS typically include a few thermistors mounted on select cells to monitor their surface temperature. Technology to track intra-cell changes that are TR precursors is becoming available. Simultaneously, the complex pathways resulting in cell-to-cell TR propagation are being successfully modelled and mapped. Innovative solutions to prevent TR and thermal propagation are being advanced. These include modern BMS for rapid monitoring the internal health of each individual cell and physical as well as chemical methods to reduce the deleterious effects of rapid cell-to-cell heat and material transport in case of TR.

Highlights

Two underlying phenomena contributing to Li-ion battery instability, which may decrease their thermal safety, are thermal runaway (TR) in an individual cell and cell-to-cell thermal propagation
Li-ion batteries rely on a battery management systems (BMS)
Most BMS designs for Li-ion batteries are fashioned after those used in the past in NiCd, nickel-metal hydride (NiMH), lead-acid and other aqueous batteries, where TR due to a vented, flammable electrolyte was not a risk

Summary

Introduction

Advances in materials properties to increase specific energy and power delivery capabilities of this technology promise to further expand its uses.[2,3] In parallel, it has been recognized that continued work is required to improve Li-ion battery safety during their entire life-cycle—from manufacturing through operation to resource recycling.[4–7] Two underlying phenomena contributing to Li-ion battery instability, which may decrease their thermal safety, are thermal runaway (TR) in an individual cell and cell-to-cell thermal propagation. Thermal safety can be improved through clearer understanding of the physicochemical properties of the Li-ion system, and the conditions necessary to maintain system stability These inherent instabilities can be traced to the complex components that constitute each Li-ion cell in a battery. Extensive efforts have been dedicated to obtain a better interpretation of thermal safety using a variety of mathematical and computational models These include elaborate deterministic models for the individual reactions that take place. Stability of different transition metal oxides and associated oxygen release have been studied separately, using mathematical models[22] and in experiments.[40] Combining these results with a CFD model at the cell-scale or higher[41] will enable concurrent evaluation of materials limitations alongside engineering constraints

Findings

Discussion

Conclusion