Battery Case Joining Structure for Defect-Resistant Laser Welding
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Solution Overview
Problem
The production of large-sized battery cases with high mechanical strength is challenging due to welding defects caused by gaps between thin plate members during laser welding, leading to inefficient production and defective products.
Innovation Solution
A battery case kit comprising two members with thickened joining parts that increase the cross-sectional area at the joined portion, preventing material shortages during welding and potential defects, and ensuring high mechanical strength without interfering with the electrode body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If two thin plate battery case members are joined by laser welding to achieve a thinner battery case, then the battery case thickness is reduced, but welding defects occur due to gaps between facing portions
Solution Approach 1:
The thickened portion is formed in advance on the battery case member before welding, creating a material reserve that compensates for gaps that may occur during facing processing. This preliminary structural modification ensures sufficient material is available at the joining part for successful welding even when alignment imperfections occur.
Solution Approach 2:
The thickened portion is localized specifically at the joining part of the battery case member, increasing the cross-sectional area only where welding occurs. This localized modification provides additional material for welding without significantly increasing the overall thickness of the battery case, thus resolving the contradiction between thin case design and welding reliability.
2Strength
If two battery case members are joined by laser welding to achieve high mechanical strength, then mechanical strength at joined portion is improved, but production efficiency decreases due to frequent defective products
Solution Approach 1:
The thickened portion is prepared in advance during manufacturing of the battery case member, ensuring that sufficient material is available for welding before the joining process begins. This prevents welding defects such as holes in the joined portion, thereby reducing defective products and improving production efficiency while maintaining high mechanical strength.
3Weight of stationary object
If thin plate battery case members are used to reduce battery case thickness, then battery case weight is reduced, but gaps occur during facing processing leading to welding defects
Solution Approach 1:
The thickened portion acts as a cushion or buffer that compensates for imprecision in facing processing. By providing extra material at the joining part, it absorbs the negative effects of gaps that occur during alignment, ensuring successful welding without requiring extremely high facing processing precision, thus enabling the use of thin plates while maintaining manufacturing feasibility.
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 prevents welding defects and enhances mechanical strength at the joined portion, allowing for efficient production of thin battery cases with improved structural integrity and reduced material wastage.
Implementation Method 1
two battery case members that are made of thin plates are made to face each other to be joined by using laser welding
Data Source
AI summary
The present disclosure provides a battery case that is formed by joining two battery case members to each other to improve the mechanical strength at a joined portion of the members. The battery case disclosed herein is a hexahedral box-shaped battery case including two rectangular wide faces, three rectangular side walls that are present between the two wide faces, and an opening part. The battery case is characterized in that the joined portion is included along the circumference (three sides) of the battery case.