Main Findings
The average battery temperature of the MFM/PCM-ATM (Microfiber Network/Phase Change Material Active Thermal Management) module is 2.27°C lower (at 11.25C discharge rate) and 3.83°C lower (at 20C discharge rate) than that of the aluminum-based ATM module, thereby extending the cycle life. At a 10% depth of discharge, the MFM/PCM-ATM module is expected to cycle 249 more times (at 11.25C) and 272 more times (at 20C) than the aluminum-based ATM module. In passive thermal management (PTM) mode, the temperature difference between the two modules further expands to 23.6°C (at 11.25C) and 17.6°C (at 20C), indicating that high discharge rates weaken the advantages of the MFM/PCM-PTM module. The aluminum module experiences higher temperature accumulation and faster aging due to its lower interfacial heat transfer coefficient and lack of latent heat capacity.
Core Conclusions
Outstanding Thermal Management Performance of MFM/PCM-ATM Module
The MFM/PCM-ATM module effectively enhances heat dissipation efficiency during high-rate cycling due to its higher interfacial heat transfer coefficient and latent heat capacity, resulting in an average battery temperature significantly lower than that of the aluminum-based module (2.27°C lower at 11.25C and 3.83°C lower at 20C).
Cycle Life Improvement from MFM/PCM Cooling
At a 10% depth of discharge, the cycle life of the MFM/PCM-ATM module is extended by 249 cycles (at 11.25C) and 272 cycles (at 20C) compared to the aluminum-based module. The fundamental reason is that the lower operating temperature delays aging mechanisms such as the thickening of the solid electrolyte interphase (SEI) layer and lithium inventory loss.
Cooling Failure Performance in Passive Thermal Management Mode
In the PTM mode without active cooling water, the MFM/PCM-PTM module still maintains a significant temperature advantage (23.6°C lower at 11.25C and 17.6°C lower at 20C). However, at high discharge rates, the PCM melts prematurely, depleting its latent heat, indicating that this module is more suitable for moderate-rate passive cooling scenarios.
Impact of Interfacial Heat Transfer and Material Properties
The interfacial heat transfer coefficient of the MFM/PCM module is over 7 times that of the aluminum module, thanks to the enhanced surface contact and fit provided by the microfiber structure. Combined with the latent heat capacity of the PCM, this module can conduct heat more efficiently, which is crucial in high-rate applications where Joule heating is significant.
Accelerating Effects of Temperature and Discharge Rate on Aging
Batteries within the aluminum module age faster due to higher temperatures, with aging rates during 11.25C and 20C discharges being 4.58% and 7.55% faster, respectively, than those of the MFM/PCM module. The aging model that couples temperature and rate effects indicates that even small temperature differences can significantly impact the state of health (SOH)—in PTM mode, over 13% capacity degradation occurs after just 5 cycles, highlighting the necessity of effective cooling for extending lifespan.
Research Methodology
Simulation Method
This study constructs a thermal-aging coupling model using COMSOL Multiphysics to simulate the performance of 12 cylindrical 602030 LFP batteries (diameter 60 mm, height 203 mm, rated capacity 40 Ah) in both aluminum and MFM/PCM modules. Both modules are analyzed under active thermal management (ATM, with cooling water flow) and passive thermal management (PTM, without cooling water) conditions. Given the significant differences in axial and radial thermal conductivity of high-power LFP batteries, a two-dimensional geometric model is employed to reduce computational costs.
Heat Transfer Model
Heat transfer follows the energy conservation equation: where is density, is specific heat capacity, is thermal conductivity, is temperature, and is the volumetric heat generation in the core region. Material properties are defined by region (battery components, aluminum module, MFM/PCM matrix).
Cycle Heat Generation Calculation
The heat generated during charging and discharging is calculated using the following formula: where charging current (3C), discharging current (11.25C) or 800 A (20C), internal resistance , (based on experimental data of a 38 Ah LFP battery at 45°C and 50% SOC), is the core volume. The reversible entropy effect has been included in the internal resistance term.
Material Parameters
The material parameters for the battery components (core, aluminum shell, heat-shrink packaging) are taken from the literature. The aluminum module uses bulk aluminum properties. The MFM/PCM module consists of 20% volume fraction copper microfiber network and 80% paraffin PCM. The equivalent parameters of the porous matrix are calculated using the volume averaging method, with thermal conductivity corrected by a geometric factor. The properties of the PCM (density, thermal conductivity, specific heat, latent heat) are defined separately for the solid and liquid phases, with the phase change process modeled using the Heaviside function.
Porous Medium Submodel
The porous medium assumes local thermal equilibrium, neglecting fluid flow and natural convection. The equivalent thermal conductivity is calculated as: where solid volume fraction , is the thermal conductivity of copper, is the thermal conductivity of paraffin, is the geometric factor. The equivalent heat capacity includes contributions from both solid and PCM.
Phase Change Material Submodel
The submodel for paraffin PCM defines parameters for both solid and liquid phases (melting point, latent heat, thermal conductivity, density, specific heat). The apparent heat capacity includes the effects of phase change latent heat: where is the equivalent specific heat capacity, is the melting latent heat, is the mass fraction. The phase change boundary uses a finer mesh to ensure convergence.
Boundary Conditions
The outer boundary is set to a constant temperature: environment at 60°C, cooling water at 42°C (simulating harsh naval conditions). The heat transfer coefficient is defined by Newton’s law of cooling, and the inner boundary of the cooling pipe calculates the heat transfer coefficient using the Dittus-Boelter correlation (flow rate of 1.5 gallons per minute, achieving 10,500 W m⁻² K⁻¹ at an inner diameter of 0.305 inches).
Contact Thermal Resistance
The interfacial heat transfer coefficient of the aluminum module is 170 W m⁻² K⁻¹ (including thermal conductive grease), while the MFM/PCM module has a heat transfer coefficient over 7 times higher due to fiber contact and preheating bonding processes. The modeling of interfacial thermal resistance allows for temperature discontinuities.
Cooling Water Temperature Rise
The total heat transfer is calculated by integrating the heat flux along the cooling pipe boundary, and the outlet water temperature rise is solved iteratively through energy balance (mass flow rate of 0.094 kg s⁻¹, water specific heat of 4180 J kg⁻¹ K⁻¹).
Aging Submodel
The capacity decay equation for LFP batteries from the literature is used: with parameters , , where Ah is the ampere-hour throughput, and is the average internal battery temperature (in Kelvin) over 5 cycles at steady state. The model adjusts the Ah throughput when scaling from a 2.2 Ah 26650 battery to a 40 Ah 602030 battery, using the average internal temperature of the core (as the surface temperature of large batteries is not representative).
Mesh Independence Verification
All module configurations undergo mesh independence analysis. The super coarse mesh (261,156–381,618 elements) of the ATM module shows a temperature difference of <0.002% compared to the regular mesh; in the PTM module, the MFM/PCM shows a deviation of 0.11% due to the complexity of phase change. Using a super coarse mesh saves computational time (taking only 41–58% of the time of the regular mesh).
Research Results
- • ATM Mode: The average battery temperature of the MFM/PCM-ATM module is 2.27°C lower than that of the aluminum module (at 11.25C) and 3.83°C lower (at 20C). Internal temperatures reach 14.4–49°C, exceeding 60°C during 20C discharge.
- • PTM Mode: Without cooling water, the MFM/PCM-PTM module exhibits better temperature rise control, with a temperature difference of 23.6°C (at 11.25C) and 17.6°C (at 20C). The PCM melts earlier during high-rate discharges.
- • Aging Prediction: At a 10% depth of discharge, the cycle life of the MFM/PCM-ATM module is longer by 249 cycles (at 11.25C) and 272 cycles (at 20C) compared to the aluminum module. After 100 cycles at 100% depth of discharge, the aging rate of the MFM/PCM module is slower by 4.58–7.55%.
- • Cooling Water Temperature Rise: The MFM/PCM module leads to a higher outlet water temperature rise due to better heat transfer (approximately 3°C at 20C), but the average temperature rise (1–1.7°C) remains within a safe range.
DOI
This public account content is a summary of the key points of the paper by a large language model, for reference only. If you are interested in the details of the research or review, please refer to the original literature (10.1016/j.jpowsour.2025.237363).
Related Articles
- • AM All-Solid-State Battery Paper: New Advances in Aluminum-Based Oxychloride Solid Electrolytes
- • Further Enhancing the Performance of Lithium Iron Phosphate: Thermally Conductive Phase Change Electrodes for In-Situ Thermal Management in Lithium-Ion Batteries
- • Modeling Temperature Characteristics of Lithium-Ion Batteries Considering State Dependence and Robust Estimation of Internal Temperature
- • Wide-Temperature High-Pressure Lithium-Ion Batteries: Low-Concentration Flame-Retardant PC-Based Electrolytes
- • AM Paper: Further Reducing Sodium Battery Costs, Sodium-Organic Batteries
- • Performance Improvement of O3-Type Layered Sodium-Ion Battery Cathode Material NFM
- • Fire-Resistant Quasi-Solid Fiber Lithium-Ion Batteries
- • Improving NFM High Voltage and Air Stability: Polymer-Assisted Yttrium Surface-Enriched Doped O3-Type Sodium-Ion Battery Cathodes
- • NFPP Improvement: Interface Engineering of Iron-Manganese-Based Mixed Phosphate Cathodes for High Energy Density and Ultra-Long Cycle Life Sodium-Ion Batteries
- • Defect Regulation of High-Entropy Oxides in Lithium-Ion Batteries: Metal Phosphorus-Induced Performance Enhancement
- • Early Warning System for Thermal Runaway in Large Capacity LFP Batteries
- • AFM Review: Progress in Core-Shell Structures and Gradient Concentration Sodium-Ion Battery Cathode Materials
- • CT Scanning and U-net Segmentation Comparative Analysis of NMC811 Batteries After Thermal Runaway Induced by Different Abuse Methods and Charging States
- • AM Sodium Battery NFM Cathode Paper: Charge Regulation and Anchoring Effects Achieving Stable High-Voltage Layered Metal Oxides in Sodium-Ion Batteries
- • Dry Coating Method for High Energy Density Batteries
- • Electro-Thermal-Mechanical Coupling Model: Predictions for Non-Uniform Behavior in Lithium-Ion Batteries
- • AFM Review: Electrode and Electrolyte Design Strategies for Fast-Charging Lithium-Ion Batteries
- • Impact of Granularity Averaging Method in P2D Model on Lithium-Ion Battery Behavior Predictions
- • AM Paper Proposes New Perspective on Hard Carbon Capacity: Low Potential Platform of Sodium-Ion Battery Hard Carbon Anodes Replacing Exponential Prediction Rules
- • In-Device Battery Failure Analysis