Thermal Interface Member with Resistive Layer for Battery Temperature Control
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Solution Overview
Problem
Rechargeable batteries in electric vehicles face performance and lifespan issues due to exposure to varying temperatures, necessitating effective temperature control to avoid extreme conditions.
Innovation Solution
A thermal interface member with a compliant electrically insulating and thermally conductive substrate, featuring an electrically conductive layer and an electrically resistive layer with a positive resistance temperature coefficient, is used to regulate temperature by sandwiching it between a cooling plate and battery cells, ensuring efficient heat transfer and maintaining the battery cells within an acceptable operating range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a thermal interface member uses a compliant electrically insulating and thermally conductive substrate with conductive and resistive layers to regulate temperature, then the temperature control effectiveness and battery performance are improved, but the device structure and manufacturing complexity increase
Solution Approach 1:
The patent combines multiple functions into a single integrated thermal interface member: thermal conduction (substrate), electrical conduction (conductive layer), electrical resistance/heating (resistive layer), and electrical insulation (substrate and cover layer). This merging of functions resolves the contradiction by achieving effective temperature control through a unified structure rather than separate components, thereby improving temperature regulation while managing device complexity through functional integration.
Solution Approach 2:
The thermal interface member employs composite material structures: a substrate made of electrically insulating and thermally conductive material, combined with conductive and resistive layers. This composite approach enables simultaneous achievement of thermal conduction, electrical insulation, and controlled heating/resistance functions, resolving the contradiction by using material composition to deliver multiple thermal management functions in one component.
2Manufacturing precision
If the thermal interface member includes multiple layers (conductive layer, resistive layer, cover layer) for effective temperature regulation, then the temperature control precision is improved, but the manufacturing process complexity increases
Solution Approach 1:
The thermal interface member is segmented into distinct functional layers: substrate, conductive layer, resistive layer, and cover layer. Each layer performs a specific function (thermal conduction, electrical conduction, heating/resistance, and protection/insulation). This segmentation enables precise temperature control through controlled heat generation and distribution, while the layered structure allows for modular manufacturing processes where each layer can be applied separately through coating, lamination, or deposition techniques.
Solution Approach 2:
The conductive and resistive layers are selectively applied to specific regions of the substrate where temperature regulation is needed. The resistive layer with positive temperature coefficient provides localized heating control, while the conductive layer ensures electrical connectivity. This local application of functional layers achieves precise temperature control at critical battery interfaces without unnecessarily complicating the entire manufacturing process.
3Reliability
If the resistive layer has a positive resistance temperature coefficient to increase resistance with temperature, then the temperature regulation reliability is improved, but the material selection and design complexity increase
Solution Approach 1:
The resistive layer with positive temperature coefficient provides inherent thermal feedback control: as temperature increases, resistance increases, which automatically reduces current flow and heat generation. This self-regulating feedback mechanism improves temperature control reliability by preventing overheating without requiring external control systems, while the material property itself serves as the feedback sensor and actuator, simplifying the overall control design.
Solution Approach 2:
The resistive material's positive temperature coefficient enables self-service temperature regulation: the material automatically adjusts its electrical resistance based on its own temperature, providing self-regulating heating control. This eliminates the need for external temperature sensors, control electronics, or active regulation mechanisms, thereby improving reliability through autonomous operation while managing design complexity by utilizing inherent material properties.
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 solution effectively regulates the temperature of battery cells, enhancing their performance and lifespan by maintaining them within an optimal range, thereby improving the overall efficiency and reliability of electric vehicle batteries.
Implementation Method 1
an electrically resistive layer disposed on the first surface of the substrate... The electrically resistive layer may be in electrical contact with the first and second electrodes of the conductive layer and may comprise a resistive material having a positive resistance temperature coefficient and a resistance that increases with an increase in temperature
Implementation Method 2
a resistive material having a positive resistance temperature coefficient and a resistance that increases with an increase in temperature
Implementation Method 3
The substrate may comprise a compliant electrically insulating and thermally conductive material, which may comprise a polymeric matrix phase and a dispersed phase of thermally conductive particles
Data Source
AI summary
A thermal interface member may comprise a substrate having a first surface and an opposite second surface, an electrically conductive layer disposed on the first surface of the substrate, and an electrically resistive layer disposed on the first surface of the substrate. The substrate may comprise a compliant electrically insulating and thermally conductive material including a polymeric matrix phase and a dispersed phase of thermally conductive particles. The conductive layer may be patterned into a first electrode and a second electrode spaced apart from the first electrode on the first surface of the substrate. The resistive layer may be in electrical contact with the first and second electrodes of the conductive layer and may comprise a resistive material having a positive resistance temperature coefficient and a resistance that increases with an increase in temperature.