Solid Electrolyte Pore Radius and Confining Pressure Control
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Solution Overview
Problem
The occurrence of short circuits in lithium batteries due to dendrite growth is a significant challenge, particularly in solid-state lithium batteries, where the use of solid electrolytes complicates the suppression of dendrite growth mechanisms different from those in liquid electrolyte batteries.
Innovation Solution
A method for producing a solid-state lithium battery module that involves forming a solid electrolyte layer using a sulfide glass with a specific ion conductor composition and applying a confining pressure to ensure the average pore radius and filling ratio are within certain ranges, thereby preventing short circuits. The sulfide glass contains Li, P, and S elements, with a PS43− structure and specific proportions of LiI, and the confining pressure is adjusted to satisfy specific relationships with the pore radius or filling ratio to suppress dendrite growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a solid electrolyte layer is formed by pressing sulfide glass, then the battery structure is simplified and productivity is improved, but dendrite growth may cause short circuits
Solution Approach 1:
The invention changes the physical and chemical parameters of the solid electrolyte layer by controlling the average pore radius (R) and adjusting the confining pressure (P) according to the formula P≦-5900R+74. This parameter optimization prevents dendrite growth while maintaining high productivity in solid state lithium battery production.
Solution Approach 2:
The invention uses a composite solid electrolyte layer made from sulfide glass containing Li, P, and S elements with a specific PS43- structure. This composite material structure provides both the mechanical properties needed for productivity and the chemical properties needed to suppress dendrite growth and prevent short circuits.
2Reliability
If confining pressure is increased to suppress dendrite growth, then short circuit prevention is improved, but manufacturing complexity increases
Solution Approach 1:
The invention simplifies manufacturing by establishing a clear mathematical relationship (P≦-5900R+74) between confining pressure and average pore radius. This allows manufacturers to control dendrite suppression through a single parameter (either pressure or pore radius) without complex multi-parameter optimization, reducing manufacturing complexity while maintaining reliability.
3Reliability
If the solid electrolyte layer is made denser to prevent dendrite growth, then short circuit prevention is improved, but ion conductivity may decrease
Solution Approach 1:
The invention optimizes the balance between density and ion conductivity by controlling the average pore radius (R) and confining pressure (P) within specific relationships. This allows the solid electrolyte layer to achieve sufficient density for dendrite suppression while maintaining adequate ion conductivity for battery performance, resolving the contradiction between reliability and energy efficiency.
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
This approach effectively suppresses the occurrence of short circuits in solid-state lithium battery modules by controlling the pore size and filling ratio of the solid electrolyte layer, enhancing the coulomb efficiency and preventing dendrite growth, even with soft lithium metal as an active material.
Implementation Method 1
a restraining member to apply a confining pressure in a thickness direction of the solid state lithium battery... in the restraining step, the solid state lithium batteries are restrained such that when the confining pressure is designated as P (MPa), the relationship: P≦−5900R+74 is satisfied
Implementation Method 2
a solid electrolyte layer formed between the cathode active material layer and the anode active material layer... a pressing step of pressing a sulfide glass having an ion conductor containing a Li element, a P element and a S element
Data Source
AI summary
The invention provides a method of producing a solid state lithium battery module in which the occurrence of short circuit caused by dendrites is suppressed. The invention solves this problem by providing a method of producing a solid state lithium battery module, including steps of: a pressing step of pressing a sulfide glass having an ion conductor containing a Li element, a P element, and a S element, and forming a solid electrolyte layer; and a restraining step of restraining a solid state lithium battery including the solid electrolyte layer, using restraining member, wherein, in the pressing step, the solid electrolyte layer is formed such that the average pore radius obtained by a mercury intrusion method is R (μm), and in the restraining step, the solid state lithium battery is restrained such that when the confining pressure is designated as P(MPa), the relationship: P≦−5900R+74 is satisfied.