Multi-Section Battery Charging for Lithium Dendrite Prevention
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Solution Overview
Problem
Conventional secondary battery charging methods, such as CC-CV charging, result in prolonged charging times and rapid battery deterioration due to overpotential and lithium dendrite formation, especially when high C-rates are used to increase charging speed, leading to inconsistent degradation rates and reduced lifespan.
Innovation Solution
A method involving multiple charging sections with specific C-rate ratios and cutoff voltages is employed, where CC-CV charging is performed in each section with gradually decreasing C-rates, maintaining a consistent negative electrode potential flatness and preventing lithium dendrite growth by setting C1:C2:C3 ratios between 3.8:2.8:0.8 to 4.2:3.2:1.2 and cutoff voltages between n-0.25 and n, ensuring the potential difference within 0.1V.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If high C-rate is used in CC charging section to increase charging speed, then charging time is reduced, but lithium dendrites are formed and battery deterioration progresses rapidly
Solution Approach 1:
The charging process is divided into multiple CC charging sections with different C-rates (first CC section at high C-rate, second CC section at lower C-rate, third CC section at even lower C-rate). This segmentation allows the battery to be charged quickly initially while preventing lithium dendrite formation in later stages when the battery is more susceptible to damage.
Solution Approach 2:
The C-rate is dynamically adjusted based on the charging state. The system transitions from high C-rate to lower C-rates as charging progresses, optimizing both charging speed and battery safety by matching the charging rate to the battery's real-time conditions.
2Reliability
If low C-rate (0.5C or less) is used in CC charging section, then battery deterioration is reduced, but charging time increases significantly
Solution Approach 1:
The charging process is divided into multiple CC charging sections with different C-rates (first CC section at high C-rate, second CC section at lower C-rate, third CC section at even lower C-rate). This segmentation allows the battery to be charged quickly initially while preventing lithium dendrite formation in later stages when the battery is more susceptible to damage.
Solution Approach 2:
The C-rate is dynamically adjusted based on the charging state. The system transitions from high C-rate to lower C-rates as charging progresses, optimizing both charging speed and battery safety by matching the charging rate to the battery's real-time conditions.
3Productivity
If stepwise C-rate change is applied during charging, then charging speed is improved, but negative electrode potential flatness becomes inconsistent and degradation rate varies by section
Solution Approach 1:
Each CC charging section is assigned a specific C-rate optimized for that charging stage. The first CC section uses high C-rate when the battery can tolerate it, while subsequent sections use progressively lower C-rates to maintain potential flatness as charging progresses and the battery becomes more sensitive to high rates.
Solution Approach 2:
The charging process is divided into multiple CC charging sections with different C-rates (first CC section at high C-rate, second CC section at lower C-rate, third CC section at even lower C-rate). This segmentation allows the battery to be charged quickly initially while preventing lithium dendrite formation in later stages when the battery is more susceptible to damage.
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
This approach significantly improves battery lifespan by maintaining consistent negative electrode potential flatness and preventing lithium dendrite formation, resulting in higher initial charging capacity and reduced degradation over cycles, while achieving faster charging without excessive heat generation or rapid deterioration.
Implementation Method 1
Such a secondary battery can be recharged and be used continually after discharging
Implementation Method 2
the graphite-based negative electrode is charged by a unique lithium insertion mechanism
Implementation Method 3
the amount of heat generated by the secondary battery increases
Data Source
AI summary
A method of charging a secondary battery, including first, second and third charging sections in which a CC-charging performed as first, second, and third Crate (C1, C2, C3), respectively, is supplied until the voltage of the secondary battery reaches a respective first, second and third charging cutoff voltage (V1), (V2), (V3) and a CV-charging is performed as the respective charging C-rate gradually decreases in response to reaching the respective charging cutoff voltage (V1), (V2), (V3), wherein the charging cutoff voltage satisfies the V1=n−(0.25˜0.15), V2 n−(0.2˜0.1), and V3=n (here, ‘n’ is an electric potential at the full charge of the secondary battery), and V1<V2<V3.