Battery Module Weld Joint Microstructure for Shock Resistance
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Solution Overview
Problem
Existing battery modules are vulnerable to external shocks and have weakened connection points due to surface defects from welding, leading to potential leakage and mechanical failure.
Innovation Solution
A battery module design with a welding joint portion featuring a bonding region and a surface region with distinct microstructures, where the surface region has a finer structure and different thermal history to minimize surface defects and improve mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If welding is used to join housing members to form a sealed internal accommodating space, then the housing achieves structural integrity and sealing, but the connection portion becomes vulnerable to external shocks and develops surface defects that reduce mechanical properties
Solution Approach 1:
The patent applies surface treatment (such as shot peening, laser peening, or surface coating) to change the physical and mechanical parameters of the welding surface. This treatment modifies surface hardness, residual stress distribution, and microstructure to enhance resistance to external shocks and prevent defect propagation, thereby resolving the contradiction between achieving structural integrity through welding and maintaining reliability under external shock conditions.
2Strength
If surface defects are removed by physical working of welded portions, then mechanical properties are improved, but manufacturing complexity and time increase
Solution Approach 1:
The patent incorporates surface treatment as a preliminary action immediately following the welding process. By applying surface treatment (such as peening or coating) while the weld is still fresh and accessible, the method removes surface defects and enhances mechanical properties without requiring complex subsequent processing steps, thus maintaining ease of manufacture while improving strength.
3Productivity
If surface defects below a certain level are allowed and defect degree is managed, then manufacturing time is reduced, but mechanical properties and sealing reliability deteriorate
Solution Approach 1:
The patent applies surface treatment to change the parameters of the welding surface, transforming the state of surface defects from harmful to controlled. By modifying surface hardness, residual stress, and microstructure through treatments like shot peening or laser peening, the method allows for faster manufacturing while maintaining or even enhancing mechanical strength and sealing reliability, thus resolving the contradiction between productivity and strength.
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 design enhances the module's resistance to external shocks, reduces the risk of leakage, and improves both mechanical strength and aesthetic finish by minimizing surface defects and impurity-induced deterioration.
Implementation Method 1
the bonding region and the surface region have different microstructures due to different thermal histories
Implementation Method 2
a bonding region in which the first base material and the second base material are melt-bonded
Data Source
AI summary
Provided is a battery module including a housing having an internal accommodating space and a plurality of battery cells located in the internal accommodating space, wherein the housing includes a welding joint portion in which a first base material of a first alloy and a second base material of a second alloy are welded, the welding joint portion includes a bonding region in which the first base material and the second base material are melt-bonded and a surface region covering the bonding region, and the bonding region and the surface region have different microstructures.