Hydrogen Storage Alloy Exceeding Theoretical Capacity via Cyclic Pressure
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Solution Overview
Problem
Conventional hydrogen storage alloys are limited by their theoretical hydrogen storage capacity and cannot exceed this value, making it difficult to store additional hydrogen beyond the calculated maximum.
Innovation Solution
A method involving repeated hydrogenation and dehydrogenation steps with pressure adjustments, where the hydrogenation step increases pressure to a second value ten times greater than the first pressure value at which the alloy stores hydrogen up to its theoretical limit, and the dehydrogenation step decreases pressure back to the first value, using hydrogen storage alloys with particle sizes less than 10nm to enhance storage efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional hydrogen storage methods are used, then hydrogen storage capacity is limited to the theoretical value, but the patent aims to exceed this theoretical value
Solution Approach 1:
The patent applies periodic action by repeatedly cycling the hydrogen storage alloy between hydrogenation (absorbing hydrogen at high pressure) and dehydrogenation (releasing hydrogen at low pressure). This cyclic process allows the alloy to progressively exceed its theoretical hydrogen storage capacity through multiple cycles, transforming the storage capacity from a static theoretical limit to a dynamic exceedable value.
Solution Approach 2:
The patent utilizes parameter changes by varying pressure conditions between hydrogenation and dehydrogenation steps. During hydrogenation, pressure is increased to force hydrogen into the alloy beyond theoretical limits; during dehydrogenation, pressure is decreased to release hydrogen. These pressure parameter changes enable the system to achieve and maintain hydrogen storage levels exceeding the theoretical value.
2Quantity of substance
If high pressure is applied to store more hydrogen, then hydrogen storage capacity increases, but the equipment complexity and safety requirements increase
Solution Approach 1:
The periodic cycling between high-pressure hydrogenation and low-pressure dehydrogenation allows the system to achieve high hydrogen storage amounts only when needed, rather than maintaining constant high pressure. This reduces the overall complexity of pressure control systems and safety requirements compared to continuous high-pressure storage.
Solution Approach 2:
The patent extracts hydrogen from the alloy during dehydrogenation at low pressure, allowing the system to operate at high pressure only during brief hydrogenation periods. This extraction approach enables high storage capacity without requiring the entire system to operate continuously at high pressure, thereby reducing equipment complexity.
3Productivity
If particle size is reduced to enhance storage efficiency, then hydrogen storage ratio improves, but manufacturing precision requirements increase
Solution Approach 1:
The patent changes the particle size parameter to less than 10nm to dramatically improve hydrogen storage efficiency. The nanoscale particle size provides sufficient surface area and reaction sites for efficient hydrogen absorption and release, achieving high productivity without requiring extremely tight particle size distributions.
Solution Approach 2:
By reducing particle size to the nanoscale, the patent creates local quality improvements at the particle level. Each nanoparticle provides high surface-to-volume ratio and numerous active sites for hydrogen interaction, enhancing overall storage efficiency while the uniform nanoscale dimension can be achieved through standard nanomaterial synthesis methods.
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 method allows hydrogen storage alloys to exceed their theoretical hydrogen storage capacity, reducing the need for high pressures and shortening the storage time, with particulate alloys of 5nm or less enabling low-pressure hydrogen storage and stable hydrogen storage ratios.
Implementation Method 1
a hydrogenation step of hydrogenating a hydrogen storage alloy of Mg2Ni or Mg6Ni while increasing pressure in an atmosphere
Implementation Method 2
a dehydrogenation step of dehydrogenating the hydrogenated hydrogen storage alloy while decreasing the pressure in the atmosphere
Data Source
Figure 1
AI summary
A hydrogen storage method is provided which enables a hydrogen storage alloy to store hydrogen up to a maximum hydrogen storage amount thereof in excess of a generally known theoretical value. In a hydrogenation step, a hydrogen storage ratio calculated as an atomic weight ratio between hydrogen and the hydrogen storage alloy is obtained beforehand as a theoretical value, a pressure at which the hydrogen storage alloy stores hydrogen up to the theoretical value is set as a first pressure value, a pressure value ten or more times greater than the first pressure value is set as a second pressure value, and pressure is increased up to the second pressure value. In a dehydrogenation step, the pressure is decreased from the second pressure value to or below the first pressure value. The hydrogenation step and the dehydrogenation step are repeatedly executed.