Graphitic Heat Spreader for Battery Thermal Management
Solution Overview
Problem
Existing battery cooling systems face challenges in effectively managing heat during high-demand conditions in electric vehicles, leading to overheating and thermal runaway, which can result in battery damage or explosion, without increasing the weight, volume, or complexity of the thermal management system.
Innovation Solution
A cooling system utilizing a graphitic heat spreader element with high thermal conductivity, coupled with a thermal interface material and a cooling mechanism, such as a heat sink or heat pipe, to efficiently dissipate heat from battery cells, thereby maintaining safe operating temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional air cooling is used, then the system is simple and lightweight, but it cannot meet cooling requirements under high discharge rates
Solution Approach 1:
The patent introduces a phase change material as an intermediary between the battery and the cooling system. This PCM absorbs heat directly from the battery through phase transition (solid to liquid), acting as a thermal buffer that enhances cooling effectiveness without requiring complex active cooling components. The PCM layer mediates the heat transfer process, allowing passive cooling to meet high discharge rate requirements.
2Reliability
If liquid cooling system is implemented, then cooling efficiency is improved, but sealing and fluid pumping accessories increase system complexity
Solution Approach 1:
The phase change material provides self-regulating cooling without requiring external pumps or complex control systems. As the battery generates heat, the PCM automatically absorbs it through phase transition, and when cooling is needed, it releases the stored cooling capacity. This self-service mechanism eliminates the need for fluid pumping accessories and complex sealing systems while maintaining high cooling efficiency.
3Temperature
If coolant velocity or cooling structure size is increased, then average temperature and temperature uniformity improve, but pack volume and weight increase
Solution Approach 1:
The patent changes the thermal management approach from active fluid cooling to passive phase change cooling. By utilizing the phase transition parameter of the PCM material, the system achieves effective heat absorption and temperature uniformity without increasing coolant velocity or cooling structure size. This parameter change allows the cooling system to maintain compact dimensions and low weight while improving temperature distribution.
4Reliability
If phase change material cooling is used, then cooling performance is improved, but costs increase preventing widespread use
Solution Approach 1:
The patent selects phase change materials with transition temperatures optimized for battery operating conditions, balancing performance and cost. By carefully choosing PCM types and concentrations, the system achieves effective cooling performance while controlling material costs. The approach also simplifies the overall system architecture, reducing costs associated with pumps, seals, and complex control systems, thereby making the solution economically viable for widespread adoption.
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
The system effectively reduces the risk of overheating and thermal runaway by rapidly transporting heat away from battery cells, enhancing safety and extending battery life without adding significant weight or complexity to the thermal management system.
Implementation Method 1
a graphitic heat spreader element (member) configured to be in thermal communication with the battery cells... and configured to transport heat generated by the battery cell(s) through the heat spreader element
Data Source
AI summary
Provided is a cooling system for a battery module or pack comprising one or a plurality of battery cells, the system comprising a graphitic heat spreader element configured to be in thermal communication with the battery cells; and a cooling mechanism or device in thermal communication with the graphitic heat spreader element and configured to transport heat generated from the battery cells through the graphitic heat spreader element to the cooling mechanism or device when the battery cell is discharged. The graphitic heat spreader element may comprise a graphitic film selected from a flexible graphite sheet or an artificial graphite film obtained from carbonization and graphitization of a carbon precursor film.