Cylindrical Solid-State Electrode Assembly With Edge Buffer Structures
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Solution Overview
Problem
Existing lithium ion batteries face safety concerns due to the use of flammable organic electrolytes, which can lead to fires or explosions in the event of a short-circuit, and there is a need for high-energy-density batteries suitable for automotive applications.
Innovation Solution
A cylindrically wound electrode assembly comprising a first solid electrolyte layer, a positive electrode layer, and a negative electrode layer, with specific buffer structures to manage thickness differences and an elastic pad to accommodate volume changes, housed in a cylindrical casing to enhance stability and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If flammable organic electrolytes are used in lithium ion batteries, then high energy density can be achieved, but safety deteriorates due to fire or explosion risks in the event of short-circuit
Solution Approach 1:
The patent changes the physical state of the electrolyte from liquid to solid, fundamentally altering the safety characteristics while maintaining energy density. The solid electrolyte layer replaces the flammable organic liquid electrolyte, eliminating fire and explosion risks while preserving the high energy density required for automotive applications
Solution Approach 2:
The patent employs a solid electrolyte that can be replaced or disposed of if degraded, ensuring safety without compromising long-term reliability. The solid electrolyte layer acts as a sacrificial safety component that prevents catastrophic failures
2Device complexity
If the width of the positive electrode active material layer is reduced to fit within the solid electrolyte layer width, then manufacturing complexity is reduced, but electrode performance may deteriorate
Solution Approach 1:
The patent resolves the width mismatch by extending the solid electrolyte layer beyond the electrode edges in the axial direction, creating an L-shaped configuration. This dimensional extension allows the electrode width to be smaller than the electrolyte width, simplifying manufacturing while maintaining full electrode performance through the buffer structure that prevents electrolyte exposure at edges
3Reliability
If buffer structures are added to accommodate width differences between electrode and electrolyte layers, then reliability is improved by preventing electrolyte exposure, but device complexity increases
Solution Approach 1:
The buffer structure is pre-formed as an integrated part of the solid electrolyte layer fabrication process, extending the electrolyte material beyond the electrode edges before assembly. This preliminary action prevents electrolyte exposure at electrode edges without requiring additional components or complex assembly steps
Solution Approach 2:
The buffer structure is merged with the solid electrolyte layer, forming a single continuous component rather than a separate additive part. This integration reduces device complexity by eliminating additional assembly steps while maintaining the protective function
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 reduces the risk of fire or explosion and maintains high energy density, providing improved stability and performance for automotive applications.
Implementation Method 1
As all-solid-state batteries do not use flammable organic dispersion mediums, the possibility of fire or explosion may be significantly reduced even in the event of a short-circuit
Implementation Method 2
an elastic pad between the electrode assembly and the cylindrical casing
Data Source
Figure 1~2
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AI summary
Example embodiments include electrode assemblies and all-solid-state batteries. The electrode assembly includes a first solid electrolyte layer, a positive electrode layer, a second solid electrolyte layer, and a negative electrode layer that are disposed along a radial direction of the electrode assembly. The positive electrode layer includes a positive electrode current collector, a first positive electrode active material layer on a first surface of the positive electrode current collector and in contact with the first solid electrolyte layer. A first width of the first positive electrode active material layer is less than a second width of the first solid electrolyte layer, a first buffer structure adjacent to a first side of the first positive electrode active material layer, and a second buffer structure adjacent to a second side of the first positive electrode active material layer.