Nickel-Coated Contact Surface for Low-Resistance Conductor Joints
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current current-carrying contact elements in electric vehicles face challenges with high contact resistance due to oxidation, requiring time-consuming and costly preparatory measures to maintain consistent and long-term connections between aluminum and copper conductors.
Innovation Solution
A current-carrying contact element with nickel-coated contact protrusions that break and seal the oxide layer, minimizing preparatory steps and ensuring stable connections by structuring the contact surfaces with recesses to absorb oxide and maintain low resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wire brushes are used to clean the surface of aluminum or copper from oxide layers, then contact resistance is reduced, but the contacting process becomes time-consuming and costly
Solution Approach 1:
The contact element is pre-coated with nickel and structured with contact protrusions and collecting recesses during manufacturing. This preliminary preparation eliminates the need for time-consuming surface cleaning operations before each contacting process, while ensuring reliable electrical contact is achieved immediately upon connection.
Solution Approach 2:
The structured contact surface with collecting recesses automatically manages oxide layers during the contacting process. The recesses self-absorb and contain oxide debris generated during connection, eliminating the need for external cleaning operations and maintaining consistent contact quality over time.
2Reliability
If the contact surface is structured with collecting recesses, then oxide layers are absorbed and contact stability is improved, but the manufacturing complexity increases
Solution Approach 1:
The contact surface is segmented into distinct functional zones: contact protrusions for electrical connection and collecting recesses for oxide management. This segmentation allows each zone to perform its specific function optimally, improving contact stability while the regular pattern keeps manufacturing relatively simple.
Solution Approach 2:
The contact surface incorporates a porous-like structure with collecting recesses that can absorb and contain oxide layers. This structured topology provides oxide management capability similar to porous materials, improving long-term contact stability without requiring complex manufacturing processes.
3Reliability
If nickel is used to break the oxide layer on aluminum conductors, then metallic contact points are formed and contact resistance is reduced, but the hardness of nickel may cause mechanical stress
Solution Approach 1:
The nickel coating is applied locally only on the contact protrusions where electrical contact occurs, rather than uniformly across the entire contact element. This localized application provides the necessary hardness to break oxide layers at critical contact points while minimizing overall mechanical stress and material usage.
Solution Approach 2:
The contact surface is divided into contact protrusions and collecting recesses. The nickel coating is applied specifically to the protrusions that bear contact pressure, while the recesses remain uncoated to absorb oxide. This segmentation allows the hard nickel to perform its oxide-breaking function only where needed, reducing unnecessary mechanical stress.
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 nickel layer effectively breaks and seals the oxide layer, reducing contact resistance to less than 5 µΩ and ensuring long-term stability by minimizing oxidation and maintaining consistent electrical connections.
Implementation Method 1
The contact element has contact protrusions with a nickel layer that can break the oxide layer on the conductor to be contacted to form metallic contact points, since nickel is harder than the aluminum of the conductor
Implementation Method 2
The hard nickel in relation to the soft aluminum, which lies under the oxide layer, causes the softer aluminum to flow and this flow breaks up the oxide
Implementation Method 3
the nickel layer enables long-term stability, as nickel can surprisingly seal the bare mating contacts against oxygen and therefore no new oxide layers can grow
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The subject matter relates to a current-carrying contact element (100) having at least one contact surface (110, 110') for electrically contacting two opposing electrical conductors (1000, 1000') in a contact direction (200). The contact element (100) comprises a base body (102) having a structured contact surface (110), the structured contact surface (110) having a plurality of collecting recesses (120) for receiving oxide between a plurality of contact protrusions (104) projecting in the contact direction (200), each contact protrusion (104) having a contact point (106) for contacting the conductor (1000) at the contact point (106); a nickel layer applied to the structured contact surface (110), the nickel layer for hardening the contact protrusions (104) so that the coated contact protrusions (104) break an oxide layer (1100) on the conductor (1000) to be contacted upon connection to the conductor (1000) to expose a bare mating contact point, and the nickel layer for sealing the contact points (106) and the bare mating contact points against oxygen; and wherein the ratio of the width (b) at the base (103) of a contact protrusion (104) to the height (h) of the contact protrusion (104) is greater than or equal to 2 and less than or equal to 10.