Hybrid-Sealed Battery Lower Case for Weld Micropore Leakage
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Solution Overview
Problem
Conventional watertight battery cases face challenges with micropores in triple welded areas, leading to potential failure in meeting IPX7 standards due to defects in welding processes, and spot welding quality is difficult to maintain, especially in high-voltage battery steel cases.
Innovation Solution
A watertight battery lower case design that combines welding and adhesive joints, with structural adhesive applied to some joint layers and welding others, featuring adhesive storage grooves to ensure adequate adhesive coverage and compensate for welding defects, thereby enhancing watertightness and productivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If triple welding is used to join the bracket and reinforcing material to the battery case, then the joining strength is improved, but the risk of micropore formation and welding defects increases
Solution Approach 1:
The patent combines welding and adhesive bonding to create a composite joining system. The bracket is welded to the battery case for primary structural strength, while adhesive is applied to seal the joint and prevent micropore formation. This composite approach leverages the high strength of welding and the sealing capability of adhesive to simultaneously achieve both strength and watertightness.
Solution Approach 2:
The patent applies adhesive beforehand to the battery case or bracket before welding, creating a protective layer that compensates for potential welding defects. The adhesive acts as a cushioning seal that prevents micropore formation and ensures watertightness even if welding imperfections occur during the joining process.
2Strength
If the joining depth of welding is increased to improve bond strength, then the strength is improved, but the occurrence of micropores and pores increases
Solution Approach 1:
The patent uses a composite joining method where welding provides primary bond strength and adhesive provides secondary sealing. This allows the welding depth to be optimized for strength without excessive penetration that would cause pores, while the adhesive layer compensates to ensure complete sealing and watertightness.
3Productivity
If spot welding is used for joining, then the productivity is improved, but the welding quality uniformity deteriorates due to welding tip wear and environmental factors
Solution Approach 1:
The patent applies adhesive beforehand to create a consistent sealing layer that compensates for variations in spot welding quality. Even if welding tip wear or environmental factors cause slight variations in weld quality, the adhesive layer ensures uniform sealing and watertightness across all joints, maintaining quality uniformity while preserving the productivity benefits of spot welding.
4Reliability
If structural adhesive is applied to all joint layers to eliminate welding, then the welding defect rate is reduced, but the adhesive curing time increases and productivity decreases
Solution Approach 1:
The patent applies adhesive selectively to specific joint layers rather than all joint layers. The adhesive is applied to the battery case or bracket at locations where sealing is most critical, while welding handles the primary structural joining. This partial application reduces the total adhesive volume and curing time while still eliminating welding defects in the most critical areas.
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
This approach reduces welding defect rates and achieves higher productivity with shorter adhesive curing times, ensuring the battery case meets watertight standards by combining the strengths of welding and adhesive methods.
Implementation Method 1
a fixing part joining and fixing the main case part, the internal bracket part, and the sub-assembly part to one another, wherein the fixing part simultaneously includes a welded joint joined by welding and an adhesive joint joined by an adhesive
Implementation Method 2
the welded joint is formed by simultaneously passing through the main case part and the internal bracket part via the welding holes
Data Source
AI summary
A watertight battery lower case with higher productivity due to a shorter adhesive curing time and a lower welding defect rate by selectively applying a structural adhesive to some joint layers of the watertight battery case and welding the other joint layers to each other, and a manufacturing method thereof.