Li-Ion Battery Control System for Dendrite Prevention
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Solution Overview
Problem
Lithium-ion batteries with lithium metal anodes face issues of dendrite formation and morphological changes, leading to potential internal shorts and inaccurate state of charge determination due to the high reactivity of lithium and its propensity to develop a sponge-like morphology during cycling.
Innovation Solution
A battery system with a processor and memory that selectively controls the charging and discharging of lithium-ion battery cell packs by evaluating criteria such as state of charge and capacity, allowing for individual cell management to prevent dendrite formation and ensure accurate state of charge determination through precise control of connection switches and charging strategies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If lithium metal anode is used to achieve high specific energy, then energy density is improved, but dendrite formation and internal shorts occur due to high reactivity and morphological changes
Solution Approach 1:
A liquid metal alloy anode is introduced as an intermediary between conventional lithium-ion and pure lithium metal anodes. This liquid metal anode maintains high specific energy while its liquid state prevents dendrite formation and morphological changes, resolving the reliability issue associated with solid lithium metal anodes
Solution Approach 2:
The anode material transitions from solid lithium metal to liquid metal alloy, changing the physical state parameter. This parameter change enables the anode to maintain high energy density while preventing dendrite formation through the liquid's ability to self-heal and redistribute uniformly during cycling
2Temperature
If conventional lithium-intercalating oxides are used in positive electrode, then voltage is maintained, but theoretical specific energy is limited to ~500 Wh/kg
Solution Approach 1:
The battery system uses a composite approach by pairing liquid metal alloy anode with high-capacity positive electrode materials such as Li2S or Li2O2. This composite material strategy enables the cell to achieve theoretical specific energies exceeding 800 Wh/kg while maintaining operational voltage through the synergistic combination of electrode materials
3Quantity of substance
If lithium metal anode is used, then capacity is increased to 3863 mAh/g, but sponge-like morphology develops during cycling leading to inaccurate state of charge determination
Solution Approach 1:
The liquid metal alloy serves as an intermediary that maintains high lithium capacity while preventing the sponge-like morphology development. The liquid state ensures uniform distribution and reversible alloying reactions, enabling accurate state of charge determination through consistent electrochemical behavior
Solution Approach 2:
The system incorporates state of charge determination mechanisms that provide feedback on the battery's charge status. The liquid metal anode's uniform electrochemical response enables more accurate feedback signals for state of charge estimation compared to solid lithium metal anodes with sponge-like morphology
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 effectively reduces the risk of dendrite formation and improves anode morphology, enhancing the accuracy of state of charge estimation and extending the life of lithium-ion batteries by ensuring complete discharge and uniform charging across cells.
Implementation Method 1
Rechargeable lithium-ion batteries are attractive energy storage systems for portable electronics and electric and hybrid-electric vehicles
Data Source
AI summary
An electrochemical battery system in one embodiment includes a first electrochemical cell, a second electrochemical cell, a memory in which command instructions are stored, and a processor configured to execute the command instructions to (i) selectively charge or discharge the first electrochemical cell based upon an evaluation of first criteria associated with the first electrochemical cell, and (ii) selectively charge or discharge the second electrochemical cell based upon an evaluation of second criteria associated with the first electrochemical cell.