All-solid battery bonding layer reduces interfacial resistance
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Solution Overview
Problem
The existing methods for manufacturing all-solid secondary batteries are not suitable for mass production due to difficulties in forming a close interface between electrode layers and the solid electrolyte layer, leading to challenges in achieving optimal battery performance and lifespan characteristics.
Innovation Solution
The introduction of a first bonding layer with a solid electrolyte having a lower Young's modulus than the solid electrolyte layer, interposed between the cathode and solid electrolyte layers, facilitates the formation of a close interface and improves battery performance by reducing interfacial resistance, using a roll press or hot press for compression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a solid electrolyte layer is directly stacked with electrode layers and pressed using a warm isostatic press, then a large-capacity all-solid secondary battery can be manufactured, but the formation of a close interface between electrode layers and the solid electrolyte layer is difficult and the method is not suitable for mass production
Solution Approach 1:
A bonding layer comprising a second solid electrolyte with lower viscosity is introduced between the first solid electrolyte layer and the electrode layers. This bonding layer acts as an intermediary that flows into the interface during pressing to form a close contact, resolving the contradiction between achieving large capacity and forming close interfaces.
Solution Approach 2:
The patent changes the viscosity parameter of the solid electrolyte by introducing a bonding layer with different viscosity characteristics. The second solid electrolyte in the bonding layer has lower viscosity compared to the first solid electrolyte, allowing it to flow and fill interface gaps during the pressing process, thereby achieving close interface formation while maintaining mass production suitability.
2Quantity of substance
If a warm isostatic press is used to compress stacked layers, then large-capacity batteries can be produced, but the method is complex and not suitable for mass production
Solution Approach 1:
The bonding layer serves as a mediator that enables simpler pressing methods to achieve the same interface quality as complex warm isostatic pressing. By introducing this intermediate layer with favorable flow characteristics, the patent simplifies the manufacturing process while maintaining high battery capacity.
3Ease of manufacture
If electrode layers are directly pressed with the solid electrolyte layer, then manufacturing steps are reduced, but the interface closeness and battery performance are compromised
Solution Approach 1:
The bonding layer comprising the second solid electrolyte acts as an intermediary that enhances interface closeness and battery performance while maintaining manufacturing simplicity. Its lower viscosity allows it to flow into interface gaps during pressing, ensuring good contact without adding significant process complexity.
Solution Approach 2:
The patent uses a composite structure with two different solid electrolytes - a first solid electrolyte for the main electrolyte layer and a second solid electrolyte with lower viscosity for the bonding layer. This composite material approach allows the bonding layer to provide the necessary flow and interface formation capabilities while the first solid electrolyte maintains the overall battery structure and performance.
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 enhances the rate properties and lifespan characteristics of the all-solid secondary battery while allowing for mass production, as demonstrated by improved discharge capacity and capacity retention ratios.
Implementation Method 1
the first bonding layer comprises a second solid electrolyte, and the second solid electrolyte has a Young's modulus which is less than a Young's modulus of the first solid electrolyte
Implementation Method 2
using a roll press or hot press for compression
Implementation Method 3
using a roll press or hot press for compression
Data Source
AI summary
An all-solid secondary battery includes an anode layer; a cathode layer; a solid electrolyte layer interposed between the anode layer and the cathode layer, and including a first solid electrolyte; and a first bonding layer disposed between the cathode layer and the solid electrolyte layer, and comprising a second solid electrolyte, wherein the anode layer includes an anode current collector and an anode active material layer disposed on the anode current collector, and the anode active material layer includes a binder and an anode active material, wherein the cathode layer includes a cathode current collector and a cathode active material layer disposed on the cathode current collector, and wherein the second solid electrolyte has a Young's modulus which is less than a Young's modulus of the first solid electrolyte.