Integrated Ni-Fe Battery-Electrolyser for Efficient Hydrogen Storage

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Solution Overview

Problem

Current solutions for grid-scale electricity storage from renewable sources face challenges such as low energy efficiency, high costs, and limited operational time due to varying renewable electricity supply, particularly for diurnal and seasonal scales.

Innovation Solution

An integrated battery-electrolyser system using nanostructured NiOOH and reduced Fe electrodes, which operates as a highly efficient energy storage and conversion device, allowing for hydrogen production beyond the battery's charge time, and utilizing thermal insulation to manage heat and extend operational time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If an integrated battery-electrolyser system is used, then energy efficiency is improved (≥81%), but device complexity increases

Engineering Contradiction:
Improveenergy efficiencyVSAvoiddevice complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent combines a battery and electrolyser into a single integrated device where the battery electrodes (Ni-Fe) serve dual functions: energy storage during charging and catalysis for hydrogen evolution during electrolysis. This merging eliminates the need for separate battery and electrolyser systems, reducing overall device complexity while achieving high energy efficiency through the synergistic use of electrode materials.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The Ni-Fe battery electrodes perform multiple functions: they store electrical energy as a battery and simultaneously catalyze hydrogen and oxygen evolution reactions during electrolysis. This multi-functionality allows the same components to serve different purposes at different operational stages, improving energy efficiency without proportionally increasing device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Loss of energy

If thermal insulation is applied to retain heat, then hydrogen production efficiency is improved, but temperature control becomes more difficult

Engineering Contradiction:
Improvehydrogen production efficiencyVSAvoidtemperature control
Core Design Contradiction:
Loss of energyVSTemperature

Solution Approach 1:

The system incorporates thermal management that monitors temperature and adjusts thermal insulation accordingly. During electrolysis, heat generated by the system is retained through insulation to improve hydrogen production efficiency, while temperature sensors and control mechanisms prevent overheating by adjusting insulation or activating cooling when necessary.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts thermal parameters by applying thermal insulation during electrolysis operations to retain beneficial heat, while implementing cooling mechanisms when temperature exceeds optimal ranges. This parameter adjustment allows the system to maximize hydrogen production efficiency while maintaining safe and effective temperature control.

Inventive Principle:
Principle #35Parameter changes

3Duration of action of moving object

If the battery operates beyond full charge to produce hydrogen, then operational time is extended, but energy efficiency decreases due to overcharging

Engineering Contradiction:
Improveoperational timeVSAvoidenergy efficiency
Core Design Contradiction:
Duration of action of moving objectVSLoss of energy

Solution Approach 1:

The system dynamically switches between battery charging mode and electrolysis mode based on real-time operational needs. When the battery reaches full charge, the system automatically transitions to using the charged electrodes for hydrogen evolution catalysis, extending operational time without the energy losses associated with continuous overcharging.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The integrated system maintains continuous useful action by seamlessly transitioning from battery charging to hydrogen production. The electrodes continuously serve their primary function of energy storage, and when fully charged, immediately begin catalyzing hydrogen evolution, ensuring no idle time and maintaining high overall energy efficiency throughout extended operational periods.

Inventive Principle:
Principle #20Continuity of useful action

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 system achieves an overall energy efficiency of ≥81% for hydrogen production, providing a robust, flexible, and cost-effective solution for both diurnal and seasonal electricity storage, with the ability to switch seamlessly between energy storage and hydrogen production.

Implementation Method 1

an electrochemical cell, in particular a Ni-Fe battery, is charged with electrical energy from an external electrical energy source

Methodology Applied
Scientific EffectElectrochemical reactions: Redox Reactions

Implementation Method 2

The charged battery electrodes consisting of nanostructured NiOOH and reduced Fe act as efficient oxygen and hydrogen evolution catalysts respectively, generating hydrogen when the battery is full

Methodology Applied
Scientific EffectElectrochemical catalysis: Catalysis

Implementation Method 3

thermal insulation and management is applied to reduce the heat loss to the environment

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 4

the heat dissipated in overpotentials of the battery is directly used in the generation of hydrogen

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP3289626B1Hybrid battery and electrolyser
Publication Date: 2019.08.28 TECH UNIV DELFT
  • EP3289626B1 patent drawingFigure 1A
  • EP3289626B1 patent drawingFigure 1B
  • EP3289626B1 patent drawingFigure 1C~1D

AI summary

The invention provides a method of storing varying or intermittent electrical energy and one or more of hydrogen (H2) and oxygen (O2) with an energy apparatus, the method comprising: providing the first cell aqueous liquid, the second cell aqueous liquid, and electrical power from an external power source to the functional unit thereby providing an electrically charged functional battery unit and one or more of hydrogen (H2) and oxygen (O2) stored in said storage system, wherein during at least part of a charging time the functional unit is charged at a potential difference between the first cell electrode and the second cell electrode of more than 1.37 V.