Solid-State Battery Laminate Voids for Crack and Short Prevention
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Solution Overview
Problem
All-solid-state secondary batteries face issues with electrode peeling and short circuits due to expansion and contraction during charging and discharging, which existing technologies fail to adequately address.
Innovation Solution
The battery design includes a laminate structure with voids in specific regions surrounded by electrode layers and electrolyte, allowing for stress relief through the formation of voids that contact the electrode active material layers, preventing cracks and short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness and area of the current collector portions joined to external terminals are increased to prevent peeling, then adhesion between current collector and external terminal is improved, but the battery structure becomes more complex and manufacturing difficulty increases
Solution Approach 1:
An adhesive layer is introduced as an intermediary substance between the current collector and the external terminal. This adhesive layer specifically bonds to both surfaces, creating a reliable connection without requiring increased thickness or area of the current collector itself. The adhesive acts as a mediator that transfers mechanical stress and electrical current between the dissimilar materials.
Solution Approach 2:
The invention changes the chemical and physical parameters of the interface between current collector and external terminal by applying a coating layer with specific adhesive properties. This coating layer has optimized bond strength, flexibility, and electrical conductivity parameters that enable reliable joining without geometric modifications to the current collector.
2Object-affected harmful factors
If the battery uses a solid electrolyte to eliminate flammable electrolytic solution, then safety is improved, but the electrode layers are more prone to peeling and cracking during expansion and contraction
Solution Approach 1:
A buffer layer is introduced beforehand between the electrode layer and the solid electrolyte layer to cushion the mechanical stress generated during charging and discharging. This buffer layer absorbs expansion and contraction forces, preventing them from transmitting to the solid electrolyte and causing cracks. The cushioning effect protects the brittle solid electrolyte from mechanical failure during cycling.
Solution Approach 2:
The buffer layer is designed as a flexible thin film that can deform elastically during electrode expansion and contraction. This flexible layer accommodates volume changes of the electrode material while maintaining continuous contact and preventing delamination. The thin film structure allows it to flex without breaking, providing ongoing mechanical protection throughout the battery's cycle life.
3Reliability
If voids are formed in the laminate to relieve stress from electrode expansion and contraction, then crack prevention is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The invention introduces a porous or void-containing layer within the laminate structure that can absorb and distribute mechanical stress. These voids act as stress relief zones that prevent crack propagation through the solid electrolyte and electrode layers. The porous structure provides multiple small voids distributed throughout the layer, creating a network of stress relief pathways that accommodate electrode expansion and contraction without concentrating stress at single points.
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 design effectively suppresses cracks and short circuits by alleviating stress from electrode expansion and contraction, enhancing the battery's durability and safety.
Implementation Method 1
a void is formed in at least one region of a region surrounded by the positive electrode layer and the first surface, a region surrounded by the positive electrode layer, the solid electrolyte layer, and the first surface, a region surrounded by the negative electrode layer and the second surface, and a region surrounded by the negative electrode layer, the solid electrolyte layer, and the second surface
Data Source
AI summary
An all-solid-state secondary battery includes a laminate wherein a positive electrode layer containing a positive electrode active material and a negative electrode layer containing a negative electrode active material are laminated with a solid electrolyte layer therebetween, and a positive electrode external terminal attached to the positive layer on a first surface of the laminate and a negative electrode external terminal attached to the negative layer on a second surface. The positive layer extends from the first surface to the second, the negative layer extends from the second surface to the first. In the laminate, a void is formed in at least one region of a region surrounded by the positive layer and first surface, a region surrounded by the positive layer, solid layer, and first surface, a region surrounded by the negative layer and second surface, and a region surrounded by the negative layer, solid layer, and second surface.