Flexible Magnetic Sensor Array for Lithium Metal Battery Monitoring
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Solution Overview
Problem
Lithium metal batteries face catastrophic failure due to dendrite growth and high surface area morphology changes, leading to internal shorts and thermal runaway, necessitating a monitoring system to detect potential failure.
Innovation Solution
A battery system incorporating flexible 2D arrays of organic p-n junction magnetic field sensors with high magneto-resistance change, integrated into the electrochemical cell to monitor local magnetic flux changes and determine the state-of-health by comparing measured magnetic fields to reference values, enabling early detection of short-circuit currents and adaptive operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If lithium metal negative electrode is used to achieve high energy density, then specific energy is improved, but dendrite growth and internal shorts occur leading to cell failure
Solution Approach 1:
The magnetic sensor is integrated into the battery cell before operation to continuously monitor current distribution and detect dendrite formation at early stages, enabling preventive action before catastrophic failure occurs
Solution Approach 2:
A magnetic sensor acts as an intermediary monitoring device that indirectly detects dendrite formation and internal shorts by measuring local magnetic fields generated by current distribution, without directly interfering with the electrochemical reactions
2Quantity of substance
If high-capacity positive electrode materials are used to maximize capacity benefit, then specific capacity is improved, but reaction at lower voltage limits theoretical specific energy
Solution Approach 1:
The magnetic sensor provides real-time feedback on current distribution and local magnetic fields, enabling monitoring of electrochemical reactions and detection of deviations from optimal operation, allowing for adaptive control to maximize energy utilization
3Duration of action of moving object
If lithium metal surface is plated and stripped during cycling, then electrochemical function is maintained, but surface roughening and dendrite formation increase surface area
Solution Approach 1:
The magnetic sensor detects surface roughening and dendrite formation at early stages during cycling, enabling preliminary intervention before the morphology changes lead to internal shorts and cell failure
Solution Approach 2:
The invention replaces direct mechanical or visual inspection of surface morphology with magnetic field sensing, which indirectly detects surface changes through their effect on current distribution and local magnetic fields
4Measurement precision
If magnetic field sensors are integrated into the electrochemical cell for monitoring, then detection capability is improved, but device complexity increases
Solution Approach 1:
The magnetic sensor serves multiple functions: monitoring current distribution, detecting dendrite formation, identifying internal shorts, and assessing state-of-health, thereby reducing the need for multiple separate monitoring systems and offsetting the added complexity with multi-functionality
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 provides early and reliable detection of short-circuit currents, preventing catastrophic failure by controlling battery operation and extending cell life through accurate monitoring of current distributions and state-of-health assessment.
Implementation Method 1
flexible 2D arrays of organic p-n junction magnetic field sensors with high magneto-resistance change
Data Source
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AI summary
In accordance with one embodiment, a battery system includes an electrochemical cell, a flexible sensor assembly attached to the cell, the flexible sensor assembly including an array of spin valve magnetic field sensors exhibiting an organic magneto resistance effect, and a battery management system operably connected to the flexible array, the battery management system including a memory with program instructions stored therein, and a processor operably connected to the memory and to the array, the processor configured to execute the program instructions to identify local changes in magnetic flux using input from the array of magnetic field sensors.