Stepped Composite Battery Pole for Reliable Current Collector Welding
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Solution Overview
Problem
The use of single metal poles in battery cells, such as copper and aluminum, leads to welding difficulties and high costs due to differences in melting points, resulting in cracking during laser welding.
Innovation Solution
A conductive structure with a first-metal post and a second-metal layer, where the second-metal layer wraps the first end and extends toward the second end, featuring a second step portion for welding to a current collector, and a concave-convex fitting interface for enhanced bonding, allowing for a smaller diameter and thinner thickness while maintaining bonding strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a composite pole with thick copper layer and large diameter is used to ensure welding effect and bonding force, then welding reliability and bonding strength are improved, but manufacturing costs increase
Solution Approach 1:
The patent applies local quality by creating a step portion only at the welding location (end surface of the copper layer) rather than uniformly thickening the entire pole. The step portion provides localized welding surface area improvement without increasing the overall pole diameter or copper layer thickness, thus maintaining cost-effectiveness while ensuring reliable welding between the copper layer and terminal pressing block.
Solution Approach 2:
The patent transitions from a two-dimensional uniform cross-section to a three-dimensional stepped structure. By adding the step portion that extends radially outward from the end surface, the welding surface area is increased in the radial dimension without increasing the axial length or overall diameter of the pole, effectively solving the welding reliability issue without proportional cost increase.
2Strength
If a composite pole with thick copper layer and large diameter is used to ensure bonding force between aluminum and copper layers, then bonding strength is improved, but manufacturing costs increase
Solution Approach 1:
The patent applies preliminary action by forming the step portion on the copper layer before the aluminum layer is applied. This pre-formed step structure provides an optimized bonding interface for the subsequent aluminum layer, ensuring strong bonding without requiring excessive copper thickness. The step portion creates mechanical interlocking that enhances bonding strength while controlling material usage and cost.
3Ease of manufacture
If single metal poles are used to reduce costs and weight, then manufacturing cost and weight are reduced, but welding reliability deteriorates due to melting point differences
Solution Approach 1:
The patent uses composite materials by combining copper and aluminum layers in a composite pole structure. The copper layer provides excellent welding performance with the aluminum terminal pressing block, while the aluminum layer reduces overall weight and cost compared to a pure copper pole. The step portion on the copper layer further enhances the welding interface, ensuring reliable bonding between the dissimilar metals.
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 design reduces manufacturing costs by enabling a smaller diameter and thinner second-metal layer while ensuring reliable welding and bonding strength, thus improving the conductive structure's overcurrent capability and reducing the risk of corrosion and detachment.
Implementation Method 1
Different metal layers are bonded together by friction welding or stamping
Implementation Method 2
when the pure copper pole and the terminal pressing block are welded by laser
Data Source
AI summary
A conductive structure, a cover plate assembly, and a battery cell are provided. The conductive structure includes a metal post and a metal layer. The metal post includes a first end and a second end opposite to each other. The first end is formed with a first step portion. The metal layer is bonded to a surface of the metal post. The metal layer wraps the first end and extends toward the second end. The metal layer is formed with a second step portion matching the first step portion. The second step portion is configured to be welded to a current collector.