Sacrificial Anode for Sodium-Metal Halide Cell Corrosion
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Solution Overview
Problem
Current high-temperature sodium-metal halide electrochemical cells face reliability issues due to separator damage from thermal cycling, pressure differential, and vibrations, leading to electrochemical corrosion of the casing and potential short-circuiting of the entire battery.
Innovation Solution
Incorporating a sacrificial metal with a lower oxidation potential than the housing material within the anode compartment, along with a tubular ion-conducting separator and shim structures for improved thermal and electrical conduction, to prevent corrosion and enhance cell reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a metallic housing is used for the electrochemical cell, then structural strength and durability are improved, but electrochemical corrosion of the housing occurs leading to reduced reliability
Solution Approach 1:
A sacrificial anode component is introduced as an intermediary element between the corrosive electrolyte environment and the metallic housing. This component preferentially undergoes oxidation, protecting the housing from corrosion through galvanic protection, thereby maintaining both structural integrity and long-term reliability
Solution Approach 2:
The sacrificial anode is designed as a consumable component with lower oxidation potential than the housing material. It intentionally corrodes over time, sacrificing itself to protect the more valuable housing structure, extending the overall cell life while maintaining structural strength
2Reliability
If thermal and electrical conductance between the core and casing is enhanced to prevent corrosion, then housing corrosion is reduced, but device complexity increases due to additional design constraints
Solution Approach 1:
The metallic housing serves multiple functions simultaneously: it provides structural containment, acts as a heat sink for thermal management, and serves as an electrical current collector. The sacrificial anode integrates with these functions by being electrically connected to the housing while chemically protecting it, reducing overall device complexity through functional convergence
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 inhibits oxidation reactions on the housing surface by allowing the sacrificial metal to corrode instead, reducing the risk of cell breaches and improving the overall reliability and thermal management of the electrochemical cell.
Implementation Method 1
The component comprises a sacrificial metal that has an oxidation potential less than the oxidation potential of the housing material
Implementation Method 2
The component comprises a sacrificial metal that has an oxidation potential less than the oxidation potential of the housing material
Implementation Method 3
A tubular ion-conducting separator disposed in a volume defined by a housing
Implementation Method 4
providing effective thermal and electrical conductance between the core of the cell and the casing
Implementation Method 5
providing effective thermal and electrical conductance between the core of the cell and the casing
Data Source
AI summary
An electrochemical cell is presented. The cell includes a housing formed of a metallic material. A component is disposed within an anode compartment of the cell that contains an alkali metal. The component comprises a sacrificial metal that has an oxidation potential less than the oxidation potential of the housing material. An energy storage device including such an electrochemical cell is also provided.