Thermoplastic Battery Lid with Conductive Coating for EMI Shielding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional battery pack housing assemblies in electric vehicles are heavy due to thick steel requirements for stiffness and durability, and they lack effective electromagnetic shielding to protect both the power cells and occupants from external influences.
Innovation Solution
A lightweight upper lid structure for battery housing made from a thermoplastic carrier coated with conductive paint or resinous material, providing electromagnetic shielding effectiveness of at least 50dB at RF frequencies between 1kHz and 1.5GHz, using conductive metal or metal-coated particles, and optionally combined with metal foils or fibers for enhanced stiffness and crash resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thick steel is used for the battery pack housing to ensure stiffness and durability, then the structural strength and durability are improved, but the weight of the housing assembly increases significantly
Solution Approach 1:
The patent employs composite materials consisting of a thermoplastic carrier combined with conductive paint containing metal or metal-coated particles. This composite structure provides both the mechanical properties needed for housing durability and the electromagnetic shielding capabilities, while significantly reducing weight compared to solid steel construction. The thermoplastic carrier provides structural integrity and the conductive coating layer provides both electromagnetic shielding and additional structural reinforcement.
Solution Approach 2:
The patent utilizes a thin thermoplastic carrier sheet that is formed into the housing shape and then coated with conductive material. This thin-film approach replaces thick steel plates, achieving the required structural strength through the combination of the thermoplastic carrier's inherent strength and the reinforcement provided by the conductive coating, while dramatically reducing overall weight.
2Ease of manufacture
If conventional non-conductive housing materials are used, then the manufacturing simplicity is maintained, but the electromagnetic shielding effectiveness is insufficient to protect power cells and occupants
Solution Approach 1:
The patent changes the electrical conductivity parameter of the housing material by applying a conductive coating to the thermoplastic carrier. The conductive paint containing metal or metal-coated particles transforms the non-conductive thermoplastic into an electromagnetically shielding material. This parameter change enables the housing to achieve at least 50dB electromagnetic shielding effectiveness across the 1kHz to 1.5GHz frequency range while maintaining the manufacturing advantages of thermoplastic materials.
3Weight of moving object
If lightweight materials are used for the upper lid, then the weight reduction is achieved, but the structural integrity and crash resistance may be compromised
Solution Approach 1:
The upper lid is constructed as a composite structure with a thermoplastic carrier providing the base structural framework and a conductive coating layer containing metal or metal-coated particles providing reinforcement. This composite construction achieves weight reduction compared to solid steel while maintaining crash resistance through the synergistic combination of the thermoplastic carrier's energy absorption capabilities and the conductive coating's structural reinforcement.
Solution Approach 2:
The conductive coating is applied to the outer surface of the thermoplastic carrier, providing localized reinforcement where it is most needed for both structural integrity and electromagnetic shielding. This local quality enhancement allows the bulk of the lid to remain lightweight thermoplastic while the coated surface provides the necessary strength and shielding 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 achieves significant weight reduction, improved electromagnetic shielding, and enhanced resistance to water, salt, and dirt, while maintaining structural integrity and safety by using a lightweight thermoplastic carrier with conductive coatings and optional reinforcement materials.
Implementation Method 1
the assembly of the thermoplastic carrier and of the coating has an electromagnetic shielding effectiveness of at least 50dB, preferably at least 60dB, at RF frequencies between 1kHz and 1.5GHz
Data Source
Figure 1~2
Figure 3
AI summary
A battery cover for the housing of a battery pack for a battery electric vehicle comprising at least a thermoplastic carrier shaped to form the covering lid characterized in that the outer surface of the covering lid not facing the battery pack is coated on the outer surface of the covering lid with a conductive paint comprising conductive metal or metal-coated particles and whereby the assembly of the thermoplastic carrier and of the coating has an electromagnetic shielding effectiveness of at least 50dB, preferably at least 60dB according to ASTM D4935-10.