Battery Tab Soldering Bridge for Low-Resistance Bonding
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Solution Overview
Problem
Existing battery pack technologies face challenges in maintaining effective electrical connections between electrode tabs and connection tabs due to differences in metal affinity with soldering materials, leading to inconsistent bonding strengths and increased electric resistance.
Innovation Solution
A battery pack design incorporating an electrode tab with a second metal material of poor affinity to the soldering material and a connection tab with a first metal material of high affinity, utilizing a soldering bridge formed by a soldering material that connects thermal bonding points across the electrode tab, ensuring strong and uniform bonding despite differences in metal affinity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a soldering material is used to bond electrode tab and connection tab, then bonding is achieved, but inconsistent bonding strength occurs due to different metal affinities
Solution Approach 1:
A nickel layer is introduced as an intermediary between the copper electrode tab and the soldering material. The nickel layer has high affinity with both copper and soldering material, serving as a mediator that ensures consistent and strong bonding. This resolves the contradiction by providing a uniform bonding interface that compensates for the varying affinities between different metal materials and the soldering material.
2Device complexity
If direct thermal bonding is applied to electrode tab and connection tab, then bonding process is simplified, but electric resistance increases due to poor metal affinity
Solution Approach 1:
The nickel layer is applied locally at the bonding interface between the electrode tab and connection tab, specifically where thermal bonding occurs. This localized application ensures high electrical conductivity at the critical bonding point without requiring the entire structure to be complex. The nickel layer's high affinity with both metals ensures low electric resistance at the interface while maintaining process simplicity.
3Reliability
If uniform bonding is achieved across conductive areas, then electrical connection is improved, but bonding process becomes more complex
Solution Approach 1:
The introduction of the nickel layer changes the material parameter at the bonding interface, creating a uniform bonding condition across the entire contact area. This parameter change (adding nickel) ensures consistent thermal and electrical properties throughout the bonding region, achieving uniform bonding without requiring complex multi-step processes or variable control mechanisms.
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 enhances bonding strength and reduces electric resistance by maintaining close contact between electrode and connection tabs, ensuring reliable charging and discharging paths through uniform thermal bonding across conductive areas.
Implementation Method 1
a soldering material bonding the electrode tab and the connection tab to each other, wherein the connection tab includes a first metal material and the electrode tab includes second metal material, the first metal material having an affinity to the soldering material that is different from an affinity of the second metal material to the soldering material
Implementation Method 2
the soldering material forms a soldering bridge that has two ends respectively corresponding to a first thermal bonding point and a second thermal bonding point to a portion of the connection tab exposed by the electrode tab
Data Source
AI summary
A battery pack includes a battery cell; an electrode tab extending from the battery cell in a first direction; a connection tab overlapping and bonded to the electrode tab; and a soldering material bonding the electrode tab to the connection tab, wherein the connection tab includes a first metal material and the electrode tab includes second metal material, the first metal material having an affinity to the soldering material that is different from an affinity of the second metal material to the soldering material, the soldering material forms a soldering bridge that has two ends respectively corresponding to first and second thermal bonding points to a portion of the connection tab exposed by the electrode tab, and the soldering bridge connects the first and second thermal bonding points to each other and extends across a portion of the electrode tab between the first and second thermal bonding points.