Nickel-Iron Battery with Carbon Negative Electrode for High Pulse Currents
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Nickel-iron accumulators are not suitable for providing high pulse currents due to their limited ability to handle high currents, and they have stability issues during overcharging, especially at high temperatures.
Innovation Solution
A cell assembly composed of two or more secondary electrochemical cells connected in parallel or series, featuring a carbon-based negative electrode with a high proportion of activated carbon or graphene for pseudocapacitive properties and nickel hydroxide-based positive electrodes, allowing for efficient storage of electrical charge and high pulse current delivery, along with a gas-tight housing to manage overcharging stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional nickel-iron accumulator design is used, then reliability and durability are improved, but the ability to deliver high pulse currents deteriorates
Solution Approach 1:
The negative electrode uses a composite material consisting of iron powder and carbon-based storage material (activated carbon or graphene). This composite structure combines the high capacity and reliability of iron with the high power density and pseudocapacitive properties of carbon, enabling the electrode to deliver both high pulse currents and maintain long-term stability.
Solution Approach 2:
The invention changes the compositional parameters of the negative electrode by incorporating carbon-based materials in specific proportions (5-50% by weight of activated carbon or graphene). This parameter modification transforms the electrode's electrochemical behavior, enabling pseudocapacitive charge storage mechanisms that support high current delivery while maintaining the underlying iron-based reliability.
2Device complexity
If traditional nickel-iron accumulator design is used, then simplicity of structure is improved, but stability during overcharging at high temperatures deteriorates
Solution Approach 1:
The carbon-based storage material in the negative electrode converts the harmful effect of overcharging (oxygen evolution and potential damage) into a beneficial process by consuming the evolved oxygen through oxidation reactions. This transforms the overcharging hazard into a self-regulating mechanism that protects the electrode structure and maintains stability even at high temperatures.
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 cell assembly can deliver high pulse currents quickly while maintaining higher capacity and stability during overcharging, especially at high temperatures, due to the carbon-based storage material's ability to consume oxygen and form an electrical double layer, enhancing the cell's durability and safety.
Implementation Method 1
a carbon-based storage material that enables the storage of electrical charge in the electrode by forming an electrical double layer (Helmholtz double layer)
Implementation Method 2
the equilibrium between the oxidized and the metallic form shifts during charging and discharging
Implementation Method 3
the carbon-based storage material in the negative electrode, which can contribute to the consumption of oxygen produced as a result of overcharging
Data Source
AI summary
A secondary electrochemical element is described, comprising a negative electrode, a positive electrode, a porous separator that separates the negative and positive electrodes, and an aqueous, alkaline electrolyte with which the electrodes and the separator are impregnated. The negative electrode has a current collector, a carbon-based storage material that enables the storage of electrical charge in the electrode by forming an electrical double layer (Helmholtz double layer), and iron in metallic and/or oxidized form. The positive electrode contains a current collector as well as nickel hydroxide and/or nickel oxyhydroxide. The carbon-based storage material is present in the negative electrode in a proportion of at least 5% by weight.