Wound Battery Current Collector Coating for Energy Density
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Solution Overview
Problem
Conventional wound foil battery structures achieve improved safety but at the cost of lower energy density due to increased volumes of non-contributing current collectors at the outer periphery.
Innovation Solution
A battery design where the current collector exposed surfaces are coated with electrode active material layers, reducing the volume of non-contributing components and enhancing energy density while maintaining safety through strategic placement and insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the thickness of foil or separator is reduced to improve energy density, then energy density increases, but safety against nail penetration is lowered
Solution Approach 1:
The battery structure is segmented into functional zones: the outer peripheral region contains current collectors without active material for safety, while the inner region contains active material for energy storage. This segmentation allows thin foils to be used in the energy-dense inner region while maintaining safety in the protective outer region.
Solution Approach 2:
Different regions of the battery are assigned different functional qualities: the outer peripheral current collectors provide safety protection without active material, while the inner current collectors provide energy storage with active material. This local differentiation resolves the contradiction between overall safety and energy density.
2Reliability
If current collectors without active material are arranged at the outer periphery to improve safety, then safety against nail penetration is improved, but the volume of non-contributing current collectors increases, lowering energy density
Solution Approach 1:
The current collector in the outer peripheral region continues to serve a useful function by providing safety protection and structural integrity, even though it does not contain active material. This transforms what would be wasted material into a functional safety component, maintaining energy density while ensuring safety.
Solution Approach 2:
The outer peripheral current collector performs multiple functions: it provides mechanical strength, prevents nail penetration, and serves as a current collection path, even without active material. This multi-functionality justifies its presence without active material, as it contributes to overall battery safety and performance.
3Quantity of substance
If the proportion of non-contributing members is decreased to improve energy density, then energy density increases, but safety is compromised
Solution Approach 1:
The outer peripheral current collector serves itself by providing safety protection without requiring active material. It independently fulfills the safety function through its structural presence and electrical conductivity, eliminating the need for additional safety components that would reduce energy density.
Data Source
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AI summary
Provided is a battery in which a positive electrode and a negative electrode, to which electrode composite materials are seamlessly applied, are wound and accommodated in an exterior member, the battery having a part where foil exposed surfaces of the positive electrode and the negative electrode face each other with an insulator therebetween, the foil exposed surfaces being formed at one-side application parts on an outer side of the winding of the respective electrodes.