Copper Collector Plate with Current Concentrator for Battery Modules
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High-power battery packs face challenges in designing lightweight, mechanically and electrically reliable collector structures that can withstand significant physical stress and temperature variations, while also requiring cost-effective and efficient manufacturing, especially when using copper collector plates for high-current applications.
Innovation Solution
The use of copper collector plates with integrated current concentrators and fusible links, which facilitate reliable resistance welding by localizing current distribution and providing controlled fusing points, enhances the interconnection between cells and collector plates, improving the structural integrity and safety of battery modules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If copper collector plates are used for high-current applications, then electrical conductivity and power output are improved, but manufacturing complexity and welding reliability deteriorate due to copper's high reflectivity and low melting point
Solution Approach 1:
A flux composition is introduced as an intermediary substance between the copper collector plate and the welding electrode. The flux penetrates the oxide layer on copper, lowers the melting point at the weld interface, and enables reliable welding of copper to steel electrodes without compromising the high electrical conductivity of the copper collector plate
Solution Approach 2:
The welding process parameters are modified by introducing a chemical agent (flux) that changes the physical state and properties of the copper surface during welding. The flux composition (containing zinc chloride, ammonium chloride, and borax) alters the melting point and surface characteristics of copper, enabling successful welding that would otherwise be difficult due to copper's inherent properties
2Weight of moving object
If collector structure weight is reduced, then energy efficiency and performance are improved, but mechanical strength and reliability deteriorate under physical stress and vibration
Solution Approach 1:
The collector structure uses a composite approach by welding copper collector plates (providing electrical conductivity) to steel electrodes (providing mechanical strength). The flux-enabled welding process creates a reliable bond between these dissimilar materials, combining the advantages of both materials to achieve both weight reduction and mechanical reliability
3Productivity
If current distribution is concentrated at weld points, then welding efficiency is improved, but local overheating and current density issues worsen
Solution Approach 1:
The flux acts as a thermal intermediary that facilitates heat transfer and distribution at the weld interface. By lowering the melting point and improving thermal contact between the copper surface and welding electrode, the flux enables efficient current transfer without excessive local overheating, allowing concentrated current paths while managing thermal effects
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 enables the creation of high-power battery modules with improved reliability, safety, and reduced weight, while maintaining cost-effectiveness by ensuring consistent and precise welding of copper collector plates to steel cells, even in high-current environments, and integrating module-level fusing for enhanced fault tolerance.
Implementation Method 1
The current concentrators may act to localize resistance welding current when welding the collector plate to underlying cells
Implementation Method 2
application of resistance welding current causes fusing of the collector arm with the cell electrode proximate the current concentrator location
Implementation Method 3
The fusible links may be formed from the collector plate as a narrowing of a collector arm, providing a locally minimized current carrying capacity
Data Source
AI summary
A battery module is formed from a plurality of battery cells having top and bottom electrodes. Top and bottom collector plates overlay, and are electrically connected with, the battery cell top and bottom electrodes. The collector plates may be formed wholly or primarily from copper. Cell apertures may be formed within the collector plates overlying each cell, with collector arms extending into said apertures for connection with an underlying cell electrode. The collector arms may include a fusible link for each cell. A bridge collector plate may span subsets of cells, and include a module-level fusible link formed therein. A current concentrator, such as a dimple or depression, may be formed in a collector arm to facilitate resistance welding of the copper collector plates to underlying battery cells, which may include electrodes formed from steel or other material more resistive than the copper collector plates.