Steel Case Secondary Battery Structural Integrity
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Solution Overview
Problem
Existing secondary batteries face challenges in terms of structural integrity and heat propagation due to the use of aluminum cases, which can lead to reduced strength and increased heat transfer between cells, potentially causing rapid deterioration and safety issues.
Innovation Solution
A secondary battery design featuring a steel case with specific geometrical and material properties, including stainless steel or carbon steel construction, and strategically placed side terminals to improve structural rigidity and reduce heat propagation by using a material with lower thermal conductivity than aluminum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If aluminum cases are used in secondary batteries, then the battery structure is lighter and easier to manufacture, but the structural integrity and strength are reduced
Solution Approach 1:
The patent changes the material parameter from aluminum to steel, fundamentally altering the physical properties of the case to achieve higher strength and lower thermal conductivity, directly resolving the contradiction between structural integrity and material weight
Solution Approach 2:
The patent employs composite construction by combining steel case material with plastic insulating layers and sealing components, creating a multi-material structure that leverages the high strength of steel while managing weight and thermal properties through material composition
2Temperature
If aluminum cases are used in secondary batteries, then manufacturing is simpler and cost-effective, but heat propagation between cells increases
Solution Approach 1:
The patent introduces plastic insulating layers and sealing components as intermediary elements between the steel case and battery cells, creating thermal barriers that reduce heat propagation while the steel case itself serves as a low thermal conductivity structural element
Solution Approach 2:
The patent changes the thermal conductivity parameter by selecting steel material with inherently lower thermal conductivity compared to aluminum, and further modifies the thermal profile by incorporating insulating plastic layers, thereby reducing heat propagation between cells
3Strength
If steel case is used instead of aluminum, then structural strength and heat resistance improve, but the weight of the battery increases
Solution Approach 1:
The patent accepts the weight penalty of steel material in exchange for achieving superior strength and thermal resistance parameters, fundamentally changing the material selection criteria to prioritize mechanical and thermal properties over weight considerations
Solution Approach 2:
The patent uses composite construction with steel case and plastic insulating components to optimize the weight-strength ratio, where the plastic elements provide necessary structural support and insulation while adding minimal weight, thereby mitigating the overall weight increase from using steel
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 steel case design enhances the structural integrity and reduces heat propagation between cells, thereby improving the battery's strength and cooling efficiency while maintaining efficient charge/discharge operations.
Implementation Method 1
reduce heat propagation by using a material with lower thermal conductivity than aluminum
Data Source
AI summary
A secondary battery includes: an electrode assembly; a case made of steel, in which openings are provided at opposite sides and in which the electrode assembly is arranged; a side terminal electrically connected to an electrode tab of the electrode assembly; and a cap plate made of steel, through which the side terminal passes and which is coupled to an opening of the openings.