Multilayer Battery Casing with Barrier and Conformal Coating
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Solution Overview
Problem
Conventional packaging structures for solid-state batteries fail to adequately protect the batteries from environmental elements due to permeability issues and poor adhesion, especially as energy density requirements increase, leading to potential oxidation and degradation of battery components.
Innovation Solution
A protective casing with a barrier layer and conformal coating that limits permeation of gases and water vapor, combined with a cap adhered to the conformal coating, providing enhanced sealing and adhesion to prevent exposure to the external environment, while allowing for expansion and contraction of the battery cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional polymer packaging structures are used, then the battery can be protected from environmental exposure, but the packaging thickness becomes insufficient to provide desired impermeability as energy density requirements increase
Solution Approach 1:
The patent employs a composite packaging structure consisting of multiple layers: a polymer substrate layer, an aluminum oxide barrier layer deposited on the substrate, and a conformal coating layer. This composite structure achieves superior impermeability to gases and moisture while maintaining reduced thickness compared to conventional single-material packaging, directly resolving the contradiction between reliability and volume.
2Volume of stationary object
If polymer packaging layers are made thinner to reduce volume, then energy density improves, but tubular channels form allowing environmental gases and vapor to penetrate the packaging
Solution Approach 1:
The aluminum oxide barrier layer serves as an intermediary between the polymer substrate and the external environment. This intermediate layer prevents the formation of tubular channels that would otherwise allow gas penetration, while enabling the polymer layer to remain thin. The conformal coating provides an additional intermediary layer that seals surface defects, maintaining sealing integrity at reduced thickness.
3Ease of manufacture
If cap adhesion to underlying packaging structure is poor, then assembly is easier, but battery cells become exposed to external environment
Solution Approach 1:
The packaging structure exhibits local quality variations with different layers providing specialized functions: the polymer substrate provides mechanical support, the aluminum oxide layer provides barrier properties, and the conformal coating layer provides enhanced adhesion for the cap. This localized functional differentiation ensures both ease of assembly and reliable protection without compromise.
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 solution effectively prevents the permeation of oxygen, nitrogen, and carbon dioxide, reducing oxidation and degradation of battery components, thereby maintaining battery capacity and internal resistance, and ensuring reliable operation across various humidity levels and charge cycles.
Implementation Method 1
the barrier layer comprising (i) an oxygen permeability or nitrogen permeability that is less than 80 cm3*mm/(m2*day), (ii) a carbon dioxide permeability that is less than 1 cm3*mm/(m2*day), and (iii) a water permeability that is less than 4 g*mm/(m2*day)
Implementation Method 2
A conformal coating covers the barrier layer, the conformal coating having a viscosity that is less than about 100,000 Pa-s at about 150° C. A cap is adhered to the conformal coating
Data Source
AI summary
A battery comprises at least one battery cell on a support, the battery cell comprising (i) an electrolyte between a plurality of electrodes, and (ii) a top surface. A protective casing having a barrier layer contacts the top surface of the battery cell, the barrier layer comprising (i) an oxygen permeability or nitrogen permeability that is less than 80 cm3*mm/(m2*day), (ii) a carbon dioxide permeability that is less than 1 cm3*mm/(m2*day), and (iii) a water permeability that is less than 4 g*mm/(m2*day). A conformal coating covers the barrier layer, the conformal coating having a viscosity that is less than about 100,000 Pa-s at about 150° C. A cap is adhered to the conformal coating.