Electron Beam Spot Welding for High-Speed Consistent Joints
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Solution Overview
Problem
Current welding techniques, such as laser and electron beam welding, face challenges in producing consistent, high-quality welds at high speeds for joining large numbers of components in complex products like electric vehicle battery packs, particularly due to issues like 'humping' and material reflectivity, which limit their effectiveness in manufacturing.
Innovation Solution
The method involves forming a series of spot welds using electron beam welding, where each spot weld is allowed to solidify before subsequent welds are formed, using electromagnetic coils to rapidly position and focus the electron beam, reducing the time spent traversing between weld locations and mitigating the 'humping' effect, resulting in consistent and high-quality joints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If continuous electron beam welding is used to join components rapidly, then welding speed increases, but humping effect occurs causing inconsistent weld quality
Solution Approach 1:
The continuous weld path is segmented into discrete spot weld locations. The electron beam forms individual spot welds at predetermined locations rather than continuously melting along the path. This segmentation prevents the humping effect while maintaining high welding speed, as each spot weld is formed and solidifies independently before the beam moves to the next location.
Solution Approach 2:
The method prevents humping by using spot welding instead of continuous welding. By concentrating energy at discrete points and allowing complete solidification between spots, the process preemptively avoids the molten material displacement that causes humping in continuous welding, ensuring consistent weld quality from the outset.
2Manufacturing precision
If laser welding is used for high precision and controllability, then welding precision improves, but beam positioning and focusing speed are limited by mechanical movement
Solution Approach 1:
The patent replaces mechanical positioning systems with electromagnetic field-based electron beam control. Electromagnetic coils rapidly deflect and focus the electron beam to different spot locations without physical movement of lenses or mirrors, achieving both high positioning precision and fast beam repositioning speeds comparable to laser welding.
3Reliability
If electron beam welding is performed under vacuum to prevent scattering, then beam quality improves, but process complexity increases
Solution Approach 1:
Instead of maintaining high vacuum throughout the entire process, the method uses a partial vacuum or controlled atmosphere sufficient to prevent excessive electron scattering. This partial action approach maintains adequate beam quality while significantly reducing vacuum system complexity and cost compared to high-vacuum requirements.
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 significantly increases welding speed and consistency, enabling the rapid joining of thousands of components, such as those in electric vehicle battery packs, with improved electrical conductivity and reduced thermal influence, leading to enhanced performance and longevity of battery assemblies.
Implementation Method 1
forming, by electron beam welding, a spot weld which joins the primary component and the first secondary component
Implementation Method 2
forming a series of spot welds using electron beam welding
Implementation Method 3
using electromagnetic coils to rapidly position and focus the electron beam
Data Source
AI summary
A method of electron beam welding a plurality of secondary components to a primary component. The method comprises: (a) on a first weld path which defines a respective section of the primary component to be welded to a first secondary component, forming, by electron beam welding, a spot weld which joins the primary component and the first secondary component at a respective spot weld location on the first weld path; and (b) on a second weld path which defines a respective section of the primary component to be welded to a second secondary component, forming, by electron beam welding, a spot weld which joins together the primary component and the second secondary component at a respective spot weld location on the second weld path. Each of steps (a) and (b) is repeated at least once, in any order, so as to form, on each of the first and second weld paths, a respective set of contiguous spot welds arranged along the respective weld path. Each successive spot weld is formed while one or more of the previous spot welds is solidifying and only after any existing spot weld(s) with which it is contiguous has solidified.