All-Solid Battery Current Collector Surface Control for Stacking
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Solution Overview
Problem
Stacking all-solid secondary batteries results in short-circuiting and poor cycle characteristics due to surface irregularities of the negative electrode current collectors, which deteriorate battery performance.
Innovation Solution
The all-solid secondary battery design includes a first current collector with smooth and slightly protruded second current collectors, where the surface of one collector has protrusions less than 8 micrometers and the other has protrusions at a density of 0 to 1 per square centimeter, preventing surface irregularities from affecting adjacent batteries during stacking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple all-solid secondary batteries are stacked to improve energy density, then the energy density increases, but surface irregularities of the negative electrode current collectors cause short-circuiting and poor cycle characteristics
Solution Approach 1:
The patent applies local quality by creating asymmetric surface treatments on the two current collectors: one current collector has a smooth surface while the other has a slightly protruded surface with controlled irregularities (protrusions of 1-10 μm height at density of 0.1-1 per cm²). This local differentiation allows the batteries to be stacked without short-circuiting while maintaining good cycle characteristics, resolving the contradiction between energy density improvement through stacking and reliability maintenance.
2Reliability
If the negative electrode current collector surface is made smooth to prevent short-circuiting, then reliability improves, but adhesion between layers may deteriorate
Solution Approach 1:
The patent employs asymmetry by treating the two current collectors differently: one current collector is kept smooth for reliable stacking and short-circuit prevention, while the other current collector is given a slightly protruded surface with controlled micro-irregularities to enhance adhesion. This asymmetric approach allows each current collector to fulfill its specific functional requirement, resolving the contradiction between reliability and adhesion strength.
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 configuration allows for the reliable stacking of multiple all-solid secondary batteries without deteriorating battery characteristics, maintaining excellent cycle performance and preventing short-circuiting.
Implementation Method 1
a solid electrolyte is used as a medium for conducting lithium ions
Data Source
AI summary
An all-solid secondary battery, including: a first current collector; a pair of first active material layers disposed on opposite sides of the first current collector; a pair of solid electrolyte layers disposed on surfaces of the pair of first active material layers; a pair of second active material layers disposed on surfaces of the pair of solid electrolyte layers; and a pair of second current collectors disposed on surfaces of the pair of second active material layers, wherein a surface of one of the pair of second current collectors opposite to a surface of one of the pair of second active material layers does not comprise protrusions having a height of greater than about 8 micrometers.