Lithium-Ion Battery Cycling With On-Demand Lithium Supplementation
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Solution Overview
Problem
Existing lithium ion batteries with third and fourth electrodes lack effective lithium supplementation methods, leading to irreversible capacity attenuation and potential safety hazards from lithium dendrite formation.
Innovation Solution
Implement a charging and discharging method that includes controlled discharge of third and fourth electrodes to supplement lithium, with adjustable current, time, and voltage conditions to maintain a high capacity retention rate, preventing lithium dendrite formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If lithium ion batteries use high voltage (4.2V or higher) to increase energy density, then energy density is improved, but battery safety deteriorates due to increased risk of decomposition and oxygen release
Solution Approach 1:
A coating layer comprising metal fluoride, metal oxide, or metal oxyfluoride is formed on the surface of the positive electrode active material particles. This coating layer acts as an intermediary barrier that prevents direct contact and harmful reactions between the high-voltage positive electrode and electrolyte, thereby enabling safe operation at 4.2V or higher while maintaining improved energy density
2Productivity
If batteries are charged at high rates to improve productivity, then charging speed is improved, but lithium plating occurs which reduces battery lifespan and causes safety issues
Solution Approach 1:
A silicon oxide layer is formed on the negative electrode before the charging process. This preliminary coating prevents lithium plating during high-rate charging by providing a protective interface that allows lithium ions to intercalate smoothly without forming metallic lithium deposits, thereby enabling fast charging while preserving battery lifespan
Solution Approach 2:
The silicon oxide layer serves as an intermediary between the negative electrode and lithium ions during charging. This intermediate layer facilitates smooth lithium ion insertion and prevents direct lithium plating on the copper current collector, enabling high-rate charging without compromising battery lifespan
3Device complexity
If conventional charging methods are used without pre-charging protocols, then charging process is simplified, but battery lifespan is reduced due to initial lithium plating and capacity loss
Solution Approach 1:
A pre-charging step at a first charge rate is performed before the main charging process. This preliminary charging action conditions the battery by establishing proper lithium distribution and preventing initial lithium plating, thereby extending battery lifespan without significantly increasing overall charging time or process complexity
Solution Approach 2:
The charging process is divided into multiple stages: a pre-charging step at lower rate followed by main charging at higher rate. This segmentation allows the battery to be properly conditioned first, preventing harmful lithium plating during the subsequent fast charging phase, thereby extending battery lifespan while maintaining reasonable charging speed
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 method achieves a capacity retention rate of at least 95% by timely lithium supplementation, reducing irreversible capacity loss and ensuring safety through controlled lithium dispersion.
Implementation Method 1
When a coating layer comprising metal fluoride, metal oxide, or metal oxyfluoride is formed on the surface of the positive electrode active material particles, the batteries can be operated at a high voltage of 4.2V or higher with improved energy density without decomposition or release of oxygen from the positive electrode
Implementation Method 2
When a silicon oxide layer is formed on the negative electrode, fast charging at a high charge rate of 10C or higher can be performed without lithium plating or loss of battery capacity
Data Source
AI summary
The present invention relates to charging and discharging methods of a lithium ion battery with a high capacity retention rate, which comprise the following steps: (1) when a number of turns is n, the negative and positive electrodes of the lithium ion battery are only charged; after the charging is finished, a third electrode and a fourth electrode are discharged with controlled current, wherein the controlled current is 0.05 - 10 A; (2) after standing for 1 hour, the fourth electrode is connected in parallel with the negative electrode of the lithium ion battery to perform the discharge with the positive electrode of the lithium ion battery; (3) common charge and discharge between the positive and negative electrodes of the lithium ion battery occur at the (n + 1) th and subsequent turns; (4) the common charge and discharge are continued until the next conditional number of turns, and steps (1) - (4) are repeated; and (5) when the number of cycles reaches the specified number of turns, the charging and discharging methods are finished; n is the conditional number of turns, which is selected from the next turn every time the discharge capacity is attenuated by 0.2 - 1%. The charging and discharging methods can release active lithium according to the self-demand of each battery cell or battery pack, so as to facilitate the capacity retention rate.