Dry Positive Electrode Lamination for Safer Solid-State Batteries
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Solution Overview
Problem
Existing lithium-ion batteries pose safety risks due to the use of flammable organic electrolyte solutions, and there is a need for high-energy-density batteries with improved safety, particularly in automotive applications.
Innovation Solution
Development of an all-solid-state battery using olivine-based lithium compounds with small average particle diameters and a dry electrode manufacturing process that includes specific ratios and combinations of positive electrode active materials, conductive materials, and dry binders, allowing for flexible electrodes that can monitor state of charge based on voltage changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If flammable organic electrolyte solutions are used in lithium-ion batteries, then high energy density can be achieved, but safety risks increase due to fire or explosion hazards
Solution Approach 1:
The patent changes the physical state of the electrolyte from liquid to solid by replacing flammable organic electrolyte solutions with solid electrolytes. This parameter change eliminates the fire and explosion hazards associated with liquid electrolytes while maintaining the battery's energy storage capability, thus resolving the contradiction between energy density and safety
Solution Approach 2:
The patent uses composite materials by combining solid electrolyte materials with electrode materials to create an all-solid-state battery system. This composite approach allows the battery to achieve both high energy density and improved safety by integrating the beneficial properties of solid electrolytes (non-flammable, stable) with active electrode materials
2Use of energy by moving object
If small average particle diameter olivine-based lithium compounds are used, then energy density improves, but electrode flexibility deteriorates
Solution Approach 1:
The patent employs a dry binder material that forms a flexible matrix or shell around the small particle diameter olivine-based lithium compounds. This flexible binder network allows the electrode to maintain flexibility and bendability even when containing numerous small particles, thus resolving the contradiction between energy density (achieved through small particles) and flexibility
Solution Approach 2:
The patent creates a composite electrode structure combining olivine-based lithium compounds with small average particle diameter with a dry binder material. This composite approach allows the small particles to provide high energy density while the binder material provides flexibility, resolving the contradiction between these two properties
3Stability of the object's composition
If dry binder is ground at low temperature (≤10°C), then mixing uniformity improves, but manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-grinding the dry binder material at low temperature (≤10°C) before mixing it with the electrode active materials. This pre-treatment of the binder ensures optimal particle size and surface properties for subsequent uniform mixing, achieving composition stability while the process is integrated into the overall manufacturing workflow
Solution Approach 2:
The patent changes the temperature parameter during binder grinding to ≤10°C to achieve improved mixing uniformity. This parameter change affects the physical properties of the binder particles, enhancing their dispersibility and compatibility with other electrode materials, thus improving composition stability
Data Source
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AI summary
A dry electrode and a manufacturing method thereof are disclosed. The method includes providing a first positive electrode active material Lia1Fex1M1-x1PO4-b1, a second positive electrode active material Lia2NiX2Coy2Dz2O2-b2, a dry binder, and a dry conductive material; forming a first mixture by mixing a first portion of the first positive electrode active material, the second positive electrode active material, the dry conductive material, and the dry binder; forming a second mixture by mixing a second portion of the first positive electrode active material with the first mixture; forming a positive electrode active material layer by forming a film from the second mixture; and performing a lamination of the positive electrode active material layer on a positive electrode current collector.