Resin Current Collector Structure for Solid-State Battery Delamination
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Solution Overview
Problem
Conventional solid-state batteries with ceramic or metal foils as current collectors face issues with discharge capacity retention due to delamination of the active material layer during charge-discharge cycles, leading to reduced ion and electron conduction paths and lower capacity retention rates.
Innovation Solution
A solid-state battery design incorporating a resin current collector with a combination of spherical carbon material and fibrous carbon material, such as acetylene black and vapor-grown carbon fibers, which absorbs internal stress and maintains conduction paths even with expansion of the active material layer, thereby reducing discharge capacity loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a ceramic foil or metal foil is used as a current collector, then the structural strength is improved, but the active material layer delaminates during charge-discharge cycles causing capacity retention to deteriorate
Solution Approach 1:
The patent uses a composite current collector consisting of a ceramic foil base layer combined with a resin layer containing spherical carbon material and fibrous carbon material. This composite structure combines the strength of ceramic/metal with the stress-absorbing properties of the resin-carbon composite, preventing delamination while maintaining structural integrity during battery charge-discharge cycles
Solution Approach 2:
The patent changes the physical parameters of the current collector by introducing a resin layer with specific softening temperature (30-80°C) and controlling the content ratios of spherical carbon material (2-13 mass%) and fibrous carbon material (15-25 mass%). These parameter changes enable the current collector to absorb expansion stress while maintaining electrical conductivity
2Strength
If confining pressure is applied by a restraint jig to inhibit delamination, then the adhesion is improved, but the device complexity increases due to the need for a large restraint jig
Solution Approach 1:
The patent extracts the confining function from an external restraint jig and integrates it into the current collector itself through the resin layer. The resin layer with softening temperature of 30-80°C provides internal confining pressure to the active material layer during charge-discharge cycles, eliminating the need for complex external restraint devices
Solution Approach 2:
The current collector's resin layer performs the confining function autonomously based on its thermal properties. When the battery operates and temperature changes occur, the resin layer automatically adjusts its softening state to provide appropriate confining pressure, making the system self-regulating without external 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
The use of a resin current collector with integrated carbon materials effectively curbs the reduction in discharge capacity by maintaining conduction paths and enhancing stress absorption, resulting in improved capacity retention and reduced delamination.
Implementation Method 1
the resin current collector including a resin, a spherical carbon material, and a fibrous carbon material... which absorbs internal stress and maintains conduction paths
Implementation Method 2
the ion conduction path and the electron conduction path tend to be severed... maintaining conduction paths even with expansion of the active material layer
Data Source
AI summary
A solid-state battery includes an electrode. The electrode includes a resin current collector including a resin, a spherical carbon material, and a fibrous carbon material and an active material layer including an active material.