Three-Dimensional Thermal Simulations of 18650 Lithium-Ion Batteries Cooled by Different Schemes under High Rate Discharging and External Shorting Conditions

Abstract

In this work, three-dimensional thermal simulations of single 18650 lithium-ion battery cell and 75 V lithium-ion battery pack composed of 21 18650 battery cells are performed based on a multi-scale multi-domain (MSMD) battery modeling approach. Different cooling approaches’ effects on 18650 lithium-ion battery and battery pack thermal management under fast discharging and external shorting conditions are investigated and compared. It is found that for the natural convection, forced air cooling, and/or mini-channel liquid cooling approaches, the temperature of battery cell easily exceeds 40 °C under 3C rate discharging condition. While under external shorting condition, the temperature of cell rises sharply and reaches the 80 °C in a short period of time, which can trigger thermal runaway and may even lead to catastrophic battery fire. On the other hand, when the cooling method is single-phase direct cooling with FC-72 as coolant or two-phase immersed cooling by HFE-7000, the cell temperature is effectively limited to a tolerable level under both high C rate discharging and external shorting conditions. In addition, two-phase immersed cooling scheme is found to lead to better temperature uniformity according to the 75 V battery pack simulations.

Enhancing battery cell safety and lifespan through strategic application of insulating and phase change materials utilizing critical thickness for enhanced heat transfer

“…The thermo-physical properties [20] of a LiFePO 4 battery cell include a specific heat capacity of around 1200 J kgK −1 , low thermal conductivity 3 W mK −1 , density of 2700 kg m −3 , and these thermo physical properties are essential for designing effective thermal management systems and ensuring the safe and efficient operation of LiFePO 4 battery cells, especially in applications such as electric vehicles and renewable energy storage.…”

“…This leads to n-type semi conduction in the graphitic negative electrode material and a shift from semiconducting to metallic character in the positive electrode material, collectively resulting in an increase in specific heat and thermal conductivity with open circuit voltage. Li, Yang, et al [20] explore battery thermal management through extensive simulations, evaluating different cooling strategies' effectiveness under high-rate discharging and external shorting conditions. Utilizing three-dimensional modelling, the research offers crucial insights into battery performance under extreme scenarios, facilitating the development of safer and more efficient battery systems.…”

Thermal Runaway Characteristics of LFP Batteries by Immersion Cooling

“…As shown in the schematic diagram (Figure ), a single battery may fall into thermal runaway (TR) due to unjustified battery construction, internal short circuit, or different abuses, such as electrical abuses (external short circuit/overcharge/overdischarge), thermal abuses, and mechanical abuses (collision/extrusion/penetration). , If there are no effective protective measures to be taken, the TR propagation process within large LIB modules will occur, eventually resulting in fire or even explosion of energy storage power stations. Researchers and an energy storage power station integrator have comprehensively studied the inducement of TR and thermal spray from the perspectives of the battery or system through experimental/simulated research, and then the corresponding strategies were proposed. − …”

Simulation Study on Stress-Strain and Deformation of Separator Under Battery Temperature Field

“…The difference between the actual and simulation values of the temperature and voltage of this established electrochemical-thermal model was within ±5%, confirming its high accuracy. Based on the MSMD battery modeling method, Li et al 12 performed a three-dimensional thermal simulation of a single battery and battery pack using a cylindrical type 18650 lithium-ion battery as the research object. They compared the effects of different cooling methods on the thermal management of the type 18650 lithium-ion batteries and battery packs.…”