Cylindrical Solid-State Electrode Assembly With Buffer Structures
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Solution Overview
Problem
Existing lithium ion batteries pose safety risks 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 risks increase due to fire or explosion possibilities
Solution Approach 1:
The patent changes the physical state of the electrolyte from liquid to solid by using a solid electrolyte layer instead of flammable organic liquid electrolytes. This parameter change eliminates the fire and explosion risks associated with liquid electrolytes while maintaining the ionic conductivity necessary for high energy density battery operation.
Solution Approach 2:
The patent employs a composite structure consisting of a solid electrolyte layer combined with positive and negative electrode layers. This composite material approach creates an all-solid-state battery system that integrates the benefits of solid electrolytes (safety) with electrode materials (energy density) to achieve both safety and high energy density simultaneously.
2Reliability
If solid electrolyte layers are used to eliminate flammable electrolytes, then safety is improved, but manufacturing complexity increases due to precise thickness requirements and buffer structures
Solution Approach 1:
The patent segments the battery structure into distinct functional layers: solid electrolyte layers, positive electrode layers, and negative electrode layers. This segmentation allows each layer to be optimized independently for its specific function while simplifying the overall manufacturing process through modular assembly of pre-fabricated layers.
Solution Approach 2:
The patent incorporates buffer structures adjacent to the electrode layers that compensate for thickness variations and volume changes before they affect the overall battery performance. These buffer structures are designed in advance to absorb dimensional discrepancies, reducing the need for extremely tight manufacturing tolerances and simplifying the manufacturing process.
3Manufacturing precision
If buffer structures are added to manage thickness differences, then manufacturing tolerance is relaxed, but device complexity increases
Solution Approach 1:
The buffer structures serve multiple functions simultaneously: they compensate for thickness variations, provide mechanical support, facilitate assembly, and accommodate volume changes during battery operation. This multi-functionality reduces the need for additional separate components, thereby maintaining manufacturing precision while minimizing the increase in device complexity.
Data Source
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.