Customizable Current Collector Surfaces for Bipolar Battery Assemblies
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Solution Overview
Problem
Lead acid batteries suffer from low energy density, poor cycling performance under high current rates, deep discharge, and high self-discharge rates due to the configuration and materials used in their current collector grids, which result in non-uniform current distribution and aging.
Innovation Solution
A customizable current collector assembly is developed using a conductive substrate with customized surface characteristics, where metal thin films and lead-tin alloy foils are applied using lamination or thermal spray techniques to create surfaces with specific properties for improved adhesion and electrochemical performance, allowing for uniform current distribution and enhanced cycle life in bipolar configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If lead alloy grids are used for supporting active material, then structural support is provided, but energy storage capacity is not contributed and energy density remains low
Solution Approach 1:
The patent changes the material parameters of the current collector from traditional lead alloy to aluminum or aluminum alloy, which fundamentally alters the weight-to-strength ratio and enables higher energy density while maintaining structural support functionality
Solution Approach 2:
The patent creates a composite structure by coating aluminum current collector with lead-tin alloy layers, combining the high strength-to-weight ratio of aluminum with the electrochemical activity of lead-tin alloy to achieve both structural support and energy storage capacity
2Ease of manufacture
If traditional current collector configuration is used, then manufacturing simplicity is maintained, but cycling performance deteriorates under high current rate or deep discharge conditions
Solution Approach 1:
The patent modifies the surface properties of the aluminum current collector through anodization to create a porous oxide layer, and applies specific lead-tin alloy coatings with controlled thickness and composition, transforming the surface parameters to enable better active material adhesion and electrochemical performance while maintaining manufacturing feasibility
Solution Approach 2:
The patent applies different treatments to different surfaces of the current collector: one surface receives anodization and coating for active material deposition, while the other surface may have different treatment for current collection, creating local quality differences that optimize both cycling performance and manufacturability
3Ease of manufacture
If conventional current collector surfaces are used, then manufacturing process is simple, but adhesion of active material layers is insufficient leading to poor electrochemical performance
Solution Approach 1:
The patent transforms the smooth aluminum surface into a porous anodized oxide layer, dramatically increasing surface area and providing anchoring sites for active material particles, thereby improving adhesion quality through controlled surface parameter modification
Solution Approach 2:
The patent introduces a lead-tin alloy coating layer as an intermediary between the aluminum current collector and the active material paste, creating a transition layer that enhances chemical bonding and mechanical adhesion while facilitating electrochemical reactions
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 provides a bipolar current collector assembly with low electrical resistance, improved adhesion of active material layers, and enhanced power performance, addressing the limitations of monopolar configurations by ensuring uniform current density and extended cycle life.
Implementation Method 1
Metal thin films can be deposited on the etched wafer surfaces
Implementation Method 2
A monocrystalline or polycrystalline substrate can be doped to achieve a desired level of conductivity
Implementation Method 3
Metal thin films can be deposited on etched silicon wafer surfaces to form one or more specified metal silicides
Implementation Method 4
Another thin layer of lead, tin, lead-alloy, or lead-tin alloy, for example, in the form of a thin foil, can be deposited on the metal surfaces
Implementation Method 5
The solution provides a bipolar current collector assembly with low electrical resistance
Data Source
AI summary
A conductive current collector with modified surfaces can be included as a portion of a bipolar battery assembly. The fabrication process can include deposition or formation of a thin film layer such as metal silicide on a surface of the current collector. Metal silicides can be created by co-sputtering or by annealing after deposition of one or more of a silicon or a metal layer. Additional layers can be provided, such as to facilitate adhesion of an active material to a current collector.