All-Solid-State Battery Electrode Filling for Expansion Control
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Solution Overview
Problem
Existing all-solid-state batteries face significant expansion due to the volume change of the negative electrode active material during charging and discharging, leading to cracking or peeling of the electrodes and deteriorating cycle characteristics.
Innovation Solution
The all-solid-state battery design involves laminating a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer in a specific order, with the filling rate of the negative electrode active material layer kept below 80%, and the positive and solid electrolyte layers having a filling rate of 85% or more, using materials like Si or Si alloys for the negative electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the filling rate of the negative electrode active material layer is increased to improve battery capacity, then the battery expands significantly during charging and discharging, causing cracking or peeling of electrodes and deteriorating cycle characteristics
Solution Approach 1:
The patent optimizes the filling rate parameter of the negative electrode active material layer, setting it to 80% or less. This parameter change allows the layer to accommodate volume expansion during charging and discharging, preventing electrode cracking and peeling while maintaining acceptable battery capacity.
2Quantity of substance
If the filling rate of the negative electrode active material layer is increased to improve energy density, then the structural integrity of the battery deteriorates due to expansion-induced cracking and peeling
Solution Approach 1:
The patent sets the filling rate of the negative electrode active material layer to 80% or less, creating sufficient void space to accommodate volume changes during electrochemical reactions. This prevents mechanical stress-induced cracking and peeling, thereby maintaining structural integrity while optimizing energy density.
Data Source
AI summary
An all-solid-state battery in which a positive electrode active material layer, a solid electrolyte layer, a negative electrode active material layer, and a negative electrode current collector are laminated in this order on at least one surface of a positive electrode current collector, wherein the negative electrode active material layer contains a negative electrode active material, and the filling rate of the negative electrode active material layer is less than 80%.