All-solid-state Battery Negative Electrode Deformation Control
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Solution Overview
Problem
Current lithium batteries using non-graphitizable carbon and nonaqueous electrolyte solutions face safety concerns due to potential abnormal heat generation and ignition during short circuits, while all-solid-state batteries with solid electrolytes offer improved safety but require a method to prevent deformation of negative electrodes made with turbostratic carbon.
Innovation Solution
A production method involving coating turbostratic carbon with a solid electrolyte and pressure-molding to reduce deformation, using a carbonaceous material with specific density and structural properties, and optimizing the volume ratio and surface characteristics to enhance bonding between the carbon and electrolyte.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If nonaqueous electrolyte solutions containing combustible organic solvents are used in lithium batteries, then excellent input/output properties are achieved, but safety deteriorates due to abnormal heat generation and ignition risks during short circuits
Solution Approach 1:
The patent changes the physical state of the electrolyte from liquid to solid, replacing combustible organic electrolyte solutions with solid electrolytes. This fundamental parameter change eliminates the safety hazards of liquid electrolytes while maintaining ionic conductivity necessary for battery operation.
Solution Approach 2:
The invention utilizes the phase transition from liquid to solid state for the electrolyte. By employing solid electrolytes instead of liquid nonaqueous electrolyte solutions, the patent eliminates ignition risks while preserving the electrochemical functionality required for excellent input/output properties.
2Ease of manufacture
If turbostratic carbon and solid electrolyte are simply mixed for negative electrode production, then manufacturing simplicity is maintained, but electrode deformation occurs due to repulsion of turbostratic carbon after pressure molding
Solution Approach 1:
The patent applies preliminary action by coating turbostratic carbon particles with solid electrolyte before pressure molding. This pre-coating step prevents repulsion and deformation during subsequent pressure molding, ensuring electrode dimensional stability while maintaining manufacturing feasibility.
Solution Approach 2:
The solid electrolyte acts as an intermediary substance that coats the turbostratic carbon particles. This intermediary layer prevents direct repulsion between carbon particles during pressure molding, eliminating electrode deformation while preserving the simplicity of the manufacturing process.
3Volume of moving object
If graphite materials with large density are used for negative electrodes, then capacity per unit volume is improved, but cycle durability deteriorates due to crystal expansion and contraction damage from repeated lithium doping and de-doping
Solution Approach 1:
The patent changes the crystal structure parameter of the carbon material from ordered graphite to disordered turbostratic structure. This structural parameter change eliminates the expansion and contraction issues of graphite while maintaining high density and capacity per unit volume, thereby improving cycle durability.
Solution Approach 2:
The invention creates a composite structure by combining turbostratic carbon with solid electrolyte. This composite material approach maintains the high density benefits of carbon materials while the solid electrolyte coating prevents structural degradation, achieving both high capacity per unit volume and excellent cycle durability.
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 method suppresses deformation and peeling between the turbostratic carbon and solid electrolyte, maintaining excellent input/output properties and cycle durability of the all-solid-state battery.
Implementation Method 1
coating turbostratic carbon with a solid electrolyte and using the turbostratic carbon coated with the solid electrolyte has a reduced negative electrode deformation ratio
Data Source
AI summary
An object of the present invention is to provide a production method for suppressing the deformation of a negative electrode in the production of a negative electrode for an all-solid-state battery using turbostratic carbon and a solid electrolyte.The problem described above can be solved by a production method for a negative electrode for an all-solid-state battery comprising the steps of:(1) coating a carbonaceous material having a true density of from 1.30 g/cm3 to 2.10 g/cm3 determined by a butanol method with a solid electrolyte; and(2) pressure-molding the solid electrolyte-coated carbonaceous material.