Hard Soldered Electrical Contact for EV Battery
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Solution Overview
Problem
High transition resistance in electrical connections of electric vehicle batteries due to large and rigid conductors, leading to increased electrical losses and heat buildup, necessitates a solution to reduce contact resistance while maintaining a strong and even connection.
Innovation Solution
An electrical contact with a recessed soldering body made of hard solder is pressed into the contact surface, protruding beyond it to ensure a full-surface contact and alignment, allowing for low transition resistance and a mechanically robust connection by filling the recess completely, preventing solder flow and ensuring uniform distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If large and rigid conductors are used for high current connections, then the mechanical strength and current carrying capacity are improved, but the transition resistance increases and electrical losses increase
Solution Approach 1:
The patent introduces a soldering body made of hard solder as an intermediary material between the contact surface and the mating contact. This soldering body fills the gap and creates a metallurgical bond, improving the electrical contact quality without requiring larger conductors. The soldering body acts as a mediator that enables low transition resistance while maintaining the original conductor dimensions.
Solution Approach 2:
The patent changes the physical state of the soldering material from solid to liquid and back to solid through controlled heating and cooling. The soldering body is heated above its melting point to become liquid, allowing it to flow and fill the recess completely, then cooled to solidify and create a strong electrical and mechanical connection. This phase change enables complete gap filling and optimal contact.
2Loss of energy
If high contact pressure is applied to reduce transition resistance, then the electrical contact quality is improved, but the mechanical deformation and surface damage increase
Solution Approach 1:
The patent utilizes the phase change of the soldering material from solid to liquid and back. By heating the soldering body above its melting point, it becomes liquid and flows into the recess under reduced pressure. Upon cooling, it solidifies and creates a strong bond without requiring excessive contact pressure that would damage the surfaces.
Solution Approach 2:
The patent employs a composite structure consisting of the contact surface, the soldering body made of hard solder material, and the mating contact. This composite approach combines the advantages of different materials: the contact surface provides structural support, the hard solder material provides low transition resistance and strong bonding, and the mating contact provides electrical connectivity. This composite structure achieves low transition resistance without excessive contact pressure.
3Loss of energy
If the contact surface area is increased to reduce transition resistance, then the electrical performance is improved, but the device size and complexity increase
Solution Approach 1:
The soldering body acts as an intermediary that enhances the effective contact area through metallurgical bonding without increasing the physical footprint of the contact assembly. The liquid solder flows into the recess and creates extensive bonding interfaces at the microscopic level, achieving low transition resistance within the existing geometric constraints.
Solution Approach 2:
The soldering body is nested within the recess of the contact surface, utilizing the available space efficiently. The recess is designed to accommodate the soldering body in its liquid state, which then solidifies to create a strong electrical connection. This nested arrangement achieves enhanced electrical performance without adding external dimensions to the device.
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 achieves a low transition resistance and a strong, uniform electrical connection with reduced heat buildup and manufacturing variability, ensuring efficient energy transfer and high-quality assembly.
Implementation Method 1
The soldering body is formed of a hard solder material and is pressed into the recess. The soldering body protrudes out from the recess beyond the contact surface.
Implementation Method 2
An electrical contact for forming a materially bonded, electrically conductive connection to a mating contact comprises a contact surface and a soldering body.
Data Source
AI summary
An electrical contact for forming a materially bonded, electrically conductive connection to a mating contact comprises a contact surface and a soldering body. The contact surface has a recess extending into the contact surface. The soldering body is formed of a hard solder material and is pressed into the recess. The soldering body protrudes out from the recess beyond the contact surface.