All-Solid-State Battery Structure for High-Pressure Interface Stability
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Solution Overview
Problem
Existing anodeless all solid state batteries face structural instability and reduced energy density due to high pressure application, leading to interface cracks and shorts between cathode and anode current collectors.
Innovation Solution
A novel battery structure with a solid electrolyte layer surrounding the cathode active material layer, an anode layer with a larger area than the cathode, and a spacer to stabilize the structure, along with a manufacturing method applying 400-800 MPa pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high pressure is applied to bond the battery layers, then interface bonding between layers is improved, but the battery structure becomes unstable and cracks occur
Solution Approach 1:
The solid electrolyte layer is designed with non-uniform thickness: a first thickness in the central region and a second thickness (greater than the first) at the peripheral region. This local variation in geometry allows the peripheral part to bear more pressure and prevent edge collapse, while the central region maintains proper bonding. This resolves the contradiction by distributing pressure locally according to structural needs.
Solution Approach 2:
A buffer layer is introduced between the solid electrolyte layer and the anode current collector. This buffer layer acts as a cushion that absorbs and distributes the high bonding pressure, preventing direct transmission of stress that would cause cathode active material layer collapse and interface cracks. The buffer layer is prepared in advance to mitigate the harmful effects of high pressure.
2Quantity of substance
If the anodeless structure is used to increase energy density, then capacity is improved, but structural stability deteriorates under high pressure
Solution Approach 1:
The solid electrolyte layer's peripheral region is designed with greater thickness to specifically address the structural instability at edges, while the central region maintains optimal thickness for ionic conductivity. This localized geometric optimization allows the anodeless structure to achieve high energy density while maintaining structural integrity under pressure.
Solution Approach 2:
The buffer layer serves as an intermediary element between the solid electrolyte layer and the anode current collector. It mediates the mechanical stress distribution, preventing direct contact and stress concentration that would lead to structural failure in the anodeless configuration, thereby enabling high energy density without sacrificing stability.
3Strength
If high pressure is applied during manufacturing, then layer bonding is improved, but interface cracks and shorts occur
Solution Approach 1:
The buffer layer is positioned in advance between the solid electrolyte layer and anode current collector to cushion the high bonding pressure. This prevents the pressure from directly causing interface cracks and shorts between the cathode current collector and anode current collector, while still achieving adequate layer bonding.
Solution Approach 2:
The solid electrolyte layer's increased peripheral thickness provides local structural reinforcement at the edges where cracks are most likely to occur during high-pressure bonding. This localized geometric modification prevents interface cracks and shorts specifically at vulnerable regions while maintaining overall bonding strength.
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
Enhances structural stability and energy density by preventing interface cracks and shorts, maintaining high capacity retention even after multiple charging cycles.
Implementation Method 1
the solid electrolyte layer (30) disposed on the cathode active material layer (20)
Implementation Method 2
an all solid state battery including a cathode current collector (10), a cathode active material layer (20)
Data Source
AI summary
An all solid state battery includes a cathode active material layer disposed in contact with a predetermined area of a cathode current collector, a solid electrolyte layer disposed on the cathode active material layer, and including a central part disposed on the cathode active material layer based on a stack direction of the all solid state battery, and a peripheral part extending from the central part and contacting the cathode current collector while surrounding side surfaces of the cathode active material layer, an anode layer disposed on the solid electrolyte layer and having an area greater than an area of the cathode active material layer but less than an area of the solid electrolyte layer, and a spacer disposed on the solid electrolyte layer and in contact with side surfaces of the anode layer.