Composite Solid-State Electrolyte for Battery Interface Contact
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Solution Overview
Problem
Sulfide solid-state electrolytes in batteries face issues of poor interfacial contact with electrodes due to high hardness and brittleness, leading to increased resistance and risks of short circuits, especially under pressure changes during charge-discharge cycling.
Innovation Solution
Incorporating an organic polymer electrolyte layer on both sides of the sulfide electrolyte layer, with specific thickness and resistance ratios, to enhance interfacial infiltration and reduce ion transmission resistance without compromising energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sulfide electrolyte layer is compacted under high pressure to reduce porosity and improve ionic conductivity, then ion transmission resistance is reduced, but interfacial contact with electrodes deteriorates due to increased hardness and brittleness
Solution Approach 1:
The patent employs a composite solid-state electrolyte structure consisting of a sulfide electrolyte layer combined with polymer electrolyte layers. The sulfide layer provides high ionic conductivity when compacted, while the polymer layers provide flexibility and good interfacial contact with electrodes, resolving the contradiction between reduced ion transmission resistance and maintained interfacial contact strength.
Solution Approach 2:
Different regions of the solid-state electrolyte are given different properties: the sulfide electrolyte layer is compacted to achieve low ion transmission resistance in the bulk, while the polymer electrolyte layers maintain softness and flexibility at the interfaces with electrodes. This local differentiation of material properties allows simultaneous optimization of both ion transmission and interfacial contact.
2Reliability
If polymer electrolyte layer thickness is increased to improve interfacial infiltration and reduce resistance, then safety performance improves, but energy density is reduced
Solution Approach 1:
The patent optimizes the thickness parameter of the polymer electrolyte layer to a specific range (5-50 μm) that balances safety performance and energy density. By precisely controlling this parameter, the polymer layer provides sufficient interfacial infiltration and safety improvement while minimizing the impact on overall battery energy density.
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 solution improves cycling performance and safety by ensuring balanced interfacial contact, reducing lithium dendrite growth and short circuits, while maintaining high energy density.
Implementation Method 1
Compared with inorganic materials, an organic polymer has some better mechanical properties (such as viscoelasticity and flexibility)
Implementation Method 2
the sulfide solid-state electrolyte has advantages of room temperature conductivity comparable to that of a liquid electrolyte
Data Source
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AI summary
The present application provides a solid-state battery, a battery module, a battery pack, and a related device thereof. On a sulfide electrolyte layer and at least one polymer electrolyte layer provided on the surface of the sulfide electrolyte layer, a solid electrolyte satisfies the following conditions: the thickness of the sulfide electrolyte layer is greater than or equal to the thickness of the polymer electrolyte layer on one side and greater than or equal to 84.2-80.2w. According to the polymer electrolyte layer having the proper thickness in the present application, an interface infiltration effect between the current sulfide electrolyte layer and an electrode can be improved, the overall energy density of the battery cannot be seriously reduced, application defects of a sulfide electrolyte in the solid-state battery are overcome to a great extent, and the cycle performance and the safety performance of the solid-state battery are improved.