Granulate Coating for Thermochemical Energy Storage Stability
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Solution Overview
Problem
Existing thermochemical energy storage materials in powder form have limited flowability and undergo significant particle size reduction during reaction cycles, leading to reduced storage capacity and impaired process control, while alternative forms like granules or pellets suffer from volume changes and disintegration.
Innovation Solution
A method involving a granulate with a reactive storage material coated with nanoparticles, where the granulate is heat-treated to form a thin, stable enveloping layer that maintains the granule's structure and allows unhindered access to reactants, preventing disintegration and maintaining storage density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If powder form storage materials are used, then storage capacity is high, but flowability is limited and particle size reduction occurs during cycles
Solution Approach 1:
A thin coating layer (1-20 μm) is applied to the surface of the granules, forming a flexible protective shell that prevents particle size reduction while maintaining flowability. The coating acts as a protective film that allows the granules to withstand reaction cycles without disintegrating into powder.
Solution Approach 2:
The storage material is formulated as a composite system combining the reactive core material (e.g., calcium oxide, metal oxides) with a coating layer material (e.g., aluminum oxide, silicon oxide, or organic binders). This composite structure provides both the chemical reactivity needed for energy storage and the mechanical stability required for good flowability.
2Ease of operation
If granules or pellets are used to improve flowability, then flowability improves, but volume change during reaction causes disintegration
Solution Approach 1:
The thin coating layer (1-20 μm) acts as a flexible shell that accommodates volume changes during thermochemical reactions. This shell prevents the granules from disintegrating despite the internal stress from expansion and contraction, maintaining both flowability and structural stability over multiple cycles.
Solution Approach 2:
The coating layer serves as a pre-applied protective cushion that absorbs and distributes the mechanical stress generated during volume changes. This beforehand cushioning prevents crack formation and disintegration, allowing the granules to maintain their integrity throughout the reaction cycles.
3Ease of operation
If additives are added to improve flowability, then flowability improves, but reactive portion is reduced and storage density decreases
Solution Approach 1:
Instead of mixing additives throughout the bulk material, a thin coating layer (1-20 μm) is applied only on the surface. This approach provides flowability improvement with minimal additive content, preserving the reactive portion and storage density while achieving the desired flow characteristics.
Solution Approach 2:
The additive or coating material is applied locally only on the surface of the granules rather than being distributed throughout the bulk. This local application provides flowability enhancement at the surface level while leaving the core reactive material intact and maximally concentrated.
4Stability of the object's composition
If tight encapsulation is used to maintain structure, then structural stability improves, but reactant access is blocked and efficiency reduces
Solution Approach 1:
A thin coating layer (1-20 μm) is applied to provide structural stability while remaining permeable to reactants. The thinness of this layer ensures it does not act as a barrier to mass transfer, allowing reactants to access the reactive core material efficiently while still providing protective functions.
Solution Approach 2:
The coating layer is designed with porous or permeable characteristics that allow reactant gases or liquids to pass through to the reactive core. This porous structure maintains structural stability while ensuring unimpeded reactant access, preserving reaction efficiency.
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 provides a stable energy storage material with improved flowability and higher volumetric storage density, ensuring the reactive component remains intact and efficient throughout multiple cycles without significant particle size reduction.
Implementation Method 1
the additive adhering to the surface of the granulate in the form of nanoparticles
Implementation Method 2
heat-treating the granulate nano-coated in this way, whereby a covering layer is formed
Data Source
AI summary
The present invention relates to a method for producing a material for thermochemical energy storage and to the material produced according to the invention.