Sealed Mandrel PCM Battery Thermal Management
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Solution Overview
Problem
Existing phase change material (PCM) based battery thermal management systems face challenges in maximizing cooling potential while minimizing weight and manufacturing costs, due to the low thermal conductivity of PCMs and the need for expanded graphite matrices, which reduces latent heat and increases costs.
Innovation Solution
A sealed mandrel filled with phase change material is embedded within the battery core, utilizing high thermal conductivity materials and eliminating the need for an external cooling matrix, thereby maximizing specific heat and reducing weight and manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If expanded graphite matrix is used to immobilize PCM and increase thermal conductivity, then thermal conductivity is improved, but latent heat is reduced and manufacturing cost increases
Solution Approach 1:
The patent introduces a metal foam matrix as an intermediary material to immobilize the PCM. The metal foam provides a three-dimensional scaffold that holds the liquid PCM in place through capillary forces, enabling thermal conductivity enhancement without requiring expanded graphite. This resolves the contradiction by providing an alternative mediator that maintains both thermal performance and latent heat content.
Solution Approach 2:
The patent changes the material parameter from expanded graphite to metal foam, fundamentally altering the immobilization mechanism. The metal foam's porous structure and surface properties are optimized to provide sufficient capillary pressure to hold the PCM liquid while maintaining high thermal conductivity through the metallic framework, thereby preserving latent heat that would otherwise be diluted by graphite content requirements.
2Reliability
If expanded graphite matrix is used to immobilize PCM, then PCM leakage is reduced, but manufacturing cost increases
Solution Approach 1:
The metal foam matrix serves as an intermediary structure that physically contains the liquid PCM through its porous network. The capillary forces generated by the metal foam's surface tension properties prevent PCM leakage without requiring the addition of expensive expanded graphite materials, thereby reducing manufacturing costs while maintaining reliability.
3Temperature
If cooling material is added to achieve best cooling effect, then thermal management performance is improved, but weight increases and volume of active charge storing material is reduced
Solution Approach 1:
The patent creates a composite material system where metal foam and PCM are combined in a specific configuration. The metal foam provides structural support and thermal conductivity, while the PCM provides latent heat storage. This composite structure achieves optimal cooling performance with minimal material mass, preventing excessive weight gain and preserving volume for active charge storing materials.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances temperature uniformity and cooling efficiency within the battery cell, allowing for a lightweight, cost-effective PCM-based internal thermal management system that maintains high latent heat without the need for expanded graphite, thus improving battery performance and lifespan.
Implementation Method 1
a sealed element filled with at least one phase change material of a plurality of phase change materials
Implementation Method 2
PCMs are liquid materials which adds extra complexity to the BTM system... PCM methodologies have a higher latent heat and overall specific heat
Implementation Method 3
utilizing high thermal conductivity materials and eliminating the need for an external cooling matrix
Data Source
AI summary
A low temperature (e.g., lower than 0° C.) or a high temperature (e.g., higher than 50° C.) can degrade battery performance, especially within lithium ion (Li-ion) batteries, and even accelerate the capacity fading. To ensure a long term and safe operation of Li-ion batteries, the battery thermal management (BTM) system becomes a crucial part to control the temperature of each discrete battery or every battery within a battery pack. Within the prior art a phase change material (PCM) has been employed combined with a graphite matrix. However, the graphite lowers the latent heat of entire BTM system and increases the manufacturing cost. Embodiments of the invention provide sealed mandrels or elements which immobilize the PCM without impacting the latent heat of the entire BTM system and increasing manufacturing costs.