Resin Current Collector Interface 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 delamination issues due to expansion and contraction of active material layers during charge-discharge cycles, leading to reduced cycle characteristics such as capacity retention rate.
Innovation Solution
A solid-state battery design incorporating a resin current collector with a conductive material and an intermediate layer where components from the active material and resin current collector are mixed, along with a Si-based active material, to enhance anchoring and prevent delamination, and a method of manufacturing involving pressing a stacked body at a temperature above the resin's softening point to form the intermediate layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a ceramic foil or metal foil is used as a current collector, then electrical conductivity is ensured, but the active material layer delaminates from the current collector due to expansion and contraction during charge-discharge cycles
Solution Approach 1:
An intermediate layer is introduced between the active material layer and the resin current collector. This intermediate layer acts as a mediator that maintains stable bonding during expansion and contraction of the active material, preventing delamination while allowing the resin current collector to flex. The intermediate layer absorbs mechanical stress and maintains electrical contact throughout charge-discharge cycles.
Solution Approach 2:
The current collector is designed as a composite structure consisting of a resin base material combined with a conductive material (such as carbon fiber or metal mesh). This composite structure provides both the flexibility needed to accommodate volume changes of the active material and sufficient electrical conductivity for battery operation. The resin component allows expansion/contraction while the conductive network maintains electron transport.
2Quantity of substance
If the active material layer is made thick to increase capacity, then energy storage is improved, but delamination occurs more easily during expansion and contraction
Solution Approach 1:
The intermediate layer provides a gradient transition zone that accommodates the mechanical stress generated by thick active material layers during expansion and contraction. This mediator layer distributes stress more evenly throughout the structure, preventing the delamination that would otherwise occur with thick active material layers.
3Strength
If a rigid current collector is used to maintain structural integrity, then mechanical strength is improved, but the active material layer cannot accommodate expansion and contraction
Solution Approach 1:
The resin current collector uses a flexible resin base material that can bend and deform to accommodate the expansion and contraction of the active material layer during charge-discharge cycles. This flexible structure maintains structural integrity while adapting to volume changes, unlike rigid current collectors that would crack or cause delamination.
Solution Approach 2:
The composite structure combines the flexibility of resin materials with the mechanical strength and electrical conductivity of conductive additives. This creates a current collector that is both strong enough to maintain structural integrity and flexible enough to accommodate active material volume changes during cycling.
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 effectively curbs delamination and improves cycle characteristics by maintaining the integrity of the active material layer with the resin current collector, enhancing charge-discharge performance and capacity retention.
Implementation Method 1
pressing a stacked body, in which a resin current collector including a thermoplastic resin and a conductive material and an active material layer including an active material are stacked, at a temperature equal to or higher than the softening temperature of the thermoplastic resin
Data Source
AI summary
A solid-state battery includes an electrode, and the electrode includes: a resin current collector including a resin and a conductive material; an active material layer including an active material; and an intermediate layer disposed between the active material layer and the resin current collector and in which at least one component included in the active material layer and at least one component included in the resin current collector are present in a mixed state.